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Nachschlagewerk zum Thema E-Zigaretten<br />
Zusammenfassung<br />
von Studien und weiteren Infor-<br />
mationen zum Thema<br />
E-Zigaretten<br />
durch die Facebook-Gruppe E-Rauchen – Wahrheiten<br />
https://www.facebook.com/pages/E-Rauchen-Wahrheiten/287019791334273<br />
- I -<br />
und
Inhaltsverzeichnis<br />
Nachschlagewerk zum Thema E-Zigaretten<br />
Deckblatt ...........................................................................................................................l<br />
Inhaltsverzeichnis ......................................................................................................... II<br />
1 Estimating the health consequences of replacing cigarettes with nicotine<br />
inhalers. ............................................................................................................. 1<br />
2 Saliva cotinine levels in users of electronic cigarettes ................................... 2<br />
3 ANALYSIS OF ELECTRONIC CIGARETTE ....................................................... 3<br />
4 Tests for the chronic toxicity of propylene glycol and triethylene glycol on<br />
monkeys and rats by vapor inhalation and oral administration. .................... 4<br />
5 Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction<br />
products: Results of an online survey of e-cigarette users. ........................... 5<br />
6 Preclinical safety evaluation of inhaled cyclosporine in propylene glycol. ... 6<br />
7 Non-clinical safety and pharmacokinetic evaluations of propylene glycol<br />
aerosol in Sprague-Dawley rats and Beagle dogs........................................... 7<br />
8 Variability among electronic cigarettes in the pressure drop, airflow rate,<br />
and aerosol production. ................................................................................... 8<br />
9 Short-term pulmonary effects of using an electronic cigarette impact on<br />
respiratory flow resistance, impedance, and exhaled nitric oxide. ................ 9<br />
10 Clinical laboratory assessment of the abuse liability of an electronic<br />
cigarette........................................................................................................... 10<br />
11 Clinical laboratory model for evaluating the acute effects of electronic<br />
cigarettes. ........................................................................................................ 11<br />
12 Commentary on Etter & Bullen (2011) ............................................................ 12<br />
13 Conventional and electronic cigarettes (e-cigarettes) have different<br />
smoking characteristics. ................................................................................ 13<br />
14 Electronic cigarettes as a smoking-cessation tool results from an online<br />
survey. ............................................................................................................. 14<br />
15 e-Cigarette awareness, use, and harm perceptions in US adults ................. 15<br />
16 Effect of an electronic nicotine delivery device e-Cigarette on smoking<br />
reduction and cessation a prospective 6-month pilot study......................... 16<br />
17 Interviews with vapers implications for future research with electronic<br />
cigarettes. ........................................................................................................ 17<br />
18 A clinical laboratory model for evaluating the acute effects of electronic<br />
cigarettes nicotine delivery profile and cardiovascular and subjective<br />
effects. ............................................................................................................. 18<br />
19 Electronic nicotine delivery devices ineffective nicotine delivery and<br />
craving suppression after acute administration. ........................................... 19<br />
20 Public Health Challenges of Electronic Cigarettes in South Korea. ............. 20<br />
21 Nicotine e-cigarette cartridges can be sold as tobacco products. ............... 21
Nachschlagewerk zum Thema E-Zigaretten<br />
22 Electronic cigarettes and thirdhand tobacco smoke two emerging health<br />
care challenges for the primary care provider............................................... 22<br />
23 FDA Electronic cigarettes may be risky. ........................................................ 23<br />
24 Mining data on usage of electronic nicotine delivery systems (ENDS) from<br />
YouTube videos .............................................................................................. 24<br />
25 Electronic cigarettes e-cigs views of aficionados and clinical public health<br />
perspectives .................................................................................................... 25<br />
26 Electronic nicotine delivery systems a research agenda.............................. 26<br />
27 Electronic cigarette users profile, utilization, satisfaction and perceived<br />
efficacy. ........................................................................................................... 27<br />
28 Electronic cigarettes a survey of users. ........................................................ 28<br />
29 Electronic cigarettes as a harm reduction strategy for tobacco control A<br />
step forward or a repeat of past mistakes ..................................................... 29<br />
30 Novel Nicotine. ................................................................................................ 30<br />
31 Electronic-cigarette smoking experience among adolescents ..................... 31<br />
32 Successful smoking cessation with electronic cigarettes in smokers with a<br />
documented history of recurring relapses a case series. ............................. 32<br />
33 Effect of an electronic nicotine delivery device e cigarette on desire to<br />
smoke and withdrawal, user preferences and nicotine delivery randomised<br />
cross-over trail. ............................................................................................... 33<br />
34 Electronic cigarettes as a method of tobacco control. ................................. 34<br />
35 WHO Study Group on Tobacco Product Regulation. .................................... 35<br />
36 WHO Study Group on Tobacco Product Regulation. (Abstrakt) ................... 36<br />
37 The effects of nicotine, denicotinized tobacco, and nicotine-containing<br />
tobacco on cigarette craving, withdrawal, and self-administration in male<br />
and female smokers. ....................................................................................... 37<br />
38 Tracking the rise in popularity of electronic nicotine delivery systems<br />
electronic cigarettes using search query surveillance. ................................ 38<br />
39 Electronic cigarettes as a harm reduction strategy for tobacco control a<br />
step forward or a repeat of past mistakes. .................................................... 39<br />
40 Chronic Idiopathic Neutrophilia in A Smoker, Relieved after Smoking<br />
Cessation with the Use of Electronic Cigarette. ............................................ 40<br />
41 Does e-cigarette consumption cause passive vaping................................... 41<br />
42 Artikel Greek study finds e-cigarettes no threat to heart. ............................. 42<br />
43 Nicotine itself is not addictive. ....................................................................... 43<br />
44 Cytotoxic FlavourArt about their opinion of Liquids with 9 mg ml nicotine. 44<br />
45 Acute impact of active and passive electronic cigarette smoking on serum<br />
cotinine and lung function. ............................................................................. 45<br />
46 VAPOR TEST RESULTS BY KOREA ELECTRONIC CIGARETTE<br />
ASSOCIATION. ................................................................................................ 46
Nachschlagewerk zum Thema E-Zigaretten<br />
47 Nicotine Molecular and physiological effects of nicotine in central nervous<br />
system . ........................................................................................................... 47<br />
48 Monoamine Oxidase Inhibitors Allow Locomotor and Rewarding Responses<br />
to Nicotine. ...................................................................................................... 48<br />
49 Uncoupling between noradrenergic and serotonergic neurons as a<br />
molecular basis of stable changes in behavior induced by repeated drugs<br />
of abuse. .......................................................................................................... 49<br />
50 Acute effects of using an electronic nicotine-delivery device (e-cigarette) on<br />
myocardial function comparison with the effects of regular cigarettes. ...... 50<br />
51 Metabolism and Disposition Kinetics of Nicotine.......................................... 51<br />
52 Electronic Cigarettes As a Smoking-Cessation Tool. ................................... 52<br />
53 Singapore-ENDS-study TobaccoControl-2012-050483.full. .......................... 53<br />
54 Adolescent Males Awareness of and Willingness to Try Electronic<br />
Cigarettes ........................................................................................................ 54<br />
55 Examination of exhaled vapor from e-cigarettes ........................................... 55<br />
56 Impact of an Electronic Cigarette on Smoking Reduction ............................ 56<br />
57 Press Release-Observation of electronic cigarette use in France ................ 57<br />
58 Electronic Nicotine Delivery Systems ............................................................ 58<br />
59 Acute effects of using an electronic nicotine-delivery divice ....................... 59<br />
60 Analysis of Components from “e-Juice XX HIGH 36mg/ml rated Nicotine... 60<br />
61 Levels of selected carcinogens and toxicants in vapour from electronic<br />
cigarettes......................................................................................................... 61<br />
62 Perceived efficacy of e-cigarettes versus nicotine........................................ 62
Nachschlagewerk zum Thema E-Zigaretten<br />
1 Estimating the health consequences of replacing<br />
cigarettes with nicotine inhalers.<br />
- 1 -
124<br />
RESEARCH PAPER<br />
Estimating the health consequences of replacing<br />
cigarettes with nicotine inhalers<br />
W Sumner II<br />
.............................................................................................................................<br />
.......................<br />
Correspondence to:<br />
Walton Sumner II,<br />
Department of Medicine,<br />
Division of General<br />
Medical Sciences, Box<br />
8005, 660 South Euclid<br />
Avenue, St Louis, MO<br />
63110, USA;<br />
wsumner@im.wustl.edu<br />
Received 17 January<br />
2002. Accepted<br />
6 February 2003<br />
.......................<br />
V arious<br />
Tobacco Control 2003;12:124–132<br />
Background: A fast acting, clean nicotine delivery system might substantially displace cigarettes. Public<br />
health consequences would depend on the subsequent prevalence of nicotine use, hazards of delivery<br />
systems, and intrinsic hazards of nicotine.<br />
Methods: A spreadsheet program, DEMANDS, estimates differences in expected mortality, adjusted<br />
for nicotine delivery system features and prevalence of nicotine use, by extending the data and methods<br />
of the SAMMEC 3 software from the US Centers for Disease Control and Prevention. The user estimates<br />
disease risks attributable to nicotine, other smoke components, and risk factors that coexist with<br />
smoking. The public health consequences of a widely used clean nicotine inhaler replacing cigarettes<br />
were compared to historical observations and public health goals, using four different risk attribution<br />
scenarios and nicotine use prevalence from 0–100%.<br />
Main outcome measures: Changes in years of potential life before age 85 (YPL85).<br />
Results: If nicotine accounts for less than a third of smokers’ excess risk of SAMMEC diseases, as it<br />
most likely does, then even with very widespread use of clean nicotine DEMANDS predicts public<br />
health gains, relative to current tobacco use. Public health benefits accruing from a widely used clean<br />
nicotine inhaler probably equal or exceed the benefits of achieving Healthy People 2010 goals.<br />
Conclusions: Clean nicotine inhalers might improve public health as much as any feasible tobacco<br />
control effort. Although the relevant risk estimates are somewhat uncertain, partial nicotine deregulation<br />
deserves consideration as part of a broad tobacco control policy.<br />
observations suggest that the health risks associated<br />
with cigarette smoking are infrequently caused by<br />
nicotine, the addictive ingredient. 12 Other components<br />
of smoke are likely contributors to smoking related disease.<br />
Cigarette smoke carries thousands of reactive chemicals,<br />
including many known toxins and carcinogens. 3 Tobacco control<br />
advocates often cite these as ample reason to quit<br />
smoking. In contrast, nicotine itself seems to be relatively<br />
safe. 1 Smoking cessation counsellors increasingly encourage<br />
long courses of nicotine to help injured smokers and special<br />
populations. 45 Certainly, nicotine replacement is safer than<br />
smoking.<br />
Potential reduced exposure products (PREPs) are nicotine<br />
delivery systems designed to expose users to fewer toxins than<br />
cigarettes do. Examples include smokeless tobacco, heated<br />
tobacco devices, and pharmaceutical nicotine replacement<br />
therapies. The Institute of Medicine report, Clearing the smoke:<br />
assessing the science base for tobacco harm reduction, described how<br />
little we know about the health consequences of PREPs in<br />
general. 2 The report suggested a broad, detailed research effort<br />
to improve our understanding of the consequences of chronic<br />
PREP use. These results would inform future PREP and<br />
tobacco regulation. However, the results of such research<br />
would not be available for many years. Furthermore, different<br />
PREP designs may have diverse health consequences.<br />
Meanwhile, pharmaceutical nicotine products receive much<br />
greater scrutiny from the US government than either the traditional<br />
or novel tobacco products they might displace. These<br />
clean nicotine products deliver pharmaceutical grade nicotine<br />
without exposing the user to any other known or suspected<br />
harmful chemicals. While tobacco companies introduce new<br />
tobacco products without review, pharmaceutical companies<br />
face significant regulatory obstacles at every step in the development<br />
of clean nicotine products. The discrepancy causes<br />
some authors to call for a “level playing field” in which regulators<br />
tolerate or even encourage some alternatives to<br />
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cigarettes. 5–10 Reversal of this historical accident requires<br />
increased regulation of tobacco products, reduced regulation<br />
of clean nicotine products, or both. Increased regulation of<br />
tobacco products is costly and controversial, and therefore will<br />
wax and wane with political and economic fortunes. Reduced<br />
regulation of clean nicotine could lead to the development of<br />
delivery systems designed to establish or maintain nicotine<br />
addiction. If people believe these products to be safer than<br />
cigarettes, then nicotine use may increase. Some smokers<br />
would switch nicotine sources rather than quit. 68 Some<br />
ex-smokers and never-smokers might become regular users,<br />
exposing these groups to the health hazards of nicotine. Injuries<br />
accruing to never-smokers and potential ex-smokers who<br />
use clean nicotine might offset illness avoided in smokers who<br />
switch to safer nicotine sources. The net public health consequences<br />
are uncertain. However, Kozlowski and colleagues 4<br />
offer as an example that habitual medicinal nicotine use<br />
might expose the user to a lifetime mortal risk of only 1 in<br />
10 000. If so, then public health would improve even if everyone<br />
used a clean nicotine product, as long as it displaced cigarettes.<br />
Although delivering nicotine without other smoke constituents<br />
should significantly reduce harms to current smokers,<br />
efforts to cleanse tobacco smoke at the point of use have failed<br />
to benefit public health. 11 The cigarette industry responded to<br />
health concerns by shifting to filtered, lower tar cigarettes<br />
between 1950 and 1970. 12 The US National Cancer Institute<br />
later attempted to develop a safe cigarette by removing harmful<br />
constituents from cigarette smoke, 13 but never developed a<br />
.............................................................<br />
Abbreviations: DEMANDS, Differences in Expected Mortality Adjusted<br />
for Nicotine Delivery Systems; PREP, potential reduced exposure<br />
products; SAMMEC, Smoking Attributable Morbidity, Mortality and<br />
Economic Costs; YPLG, years of potential life gained; YPLL, years of<br />
potential life lost
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Replacing cigarettes with nicotine inhalers 125<br />
viable product. The RJ Reynolds–Nabisco company tested two<br />
nearly smokeless heated tobacco devices, 14 and Philip Morris<br />
has developed a novel tobacco product to deliver low doses of<br />
nicotine. 2 No tobacco product has yet removed all offensive<br />
components of tobacco smoke.<br />
Existing nicotine replacement products have not displaced<br />
cigarettes in the market to supply chronic nicotine users. 15 The<br />
probability of long term use of currently available pure nicotine<br />
products is relatively low. 16 Polacrilex gum, transdermal patches,<br />
nasal spray, and shallow inhalers 17 produce much lower and<br />
slower peak arterial nicotine concentrations than cigarettes, and<br />
may have annoying side effects. A deeply inhaled nicotine powder<br />
or aerosol could supply nicotine to the arterial circulation as<br />
efficiently as a cigarette, but would maintain nicotine dependence<br />
rather than facilitate smoking cessation. A PREP delivering<br />
essentially pure nicotine by deep inhalation may be called a<br />
clean nicotine inhaler. One prototype for a clean nicotine inhaler<br />
has been developed, tested, and patented, but is not being produced<br />
commercially. 18 Other designs might reuse the powder<br />
inhaler devices that deliver corticosteroids to patients with<br />
chronic lung diseases. Legislative and regulatory constraints<br />
increase the time and expense of commercial development, or<br />
limit or prohibit marketing, as the history of the nicotine nasal<br />
inhaler demonstrates. 10<br />
Although some observers might welcome a competitive market<br />
to supply chronic nicotine users, 6 19–21 others have discouraged<br />
chronic nicotine use because of health risks. 22 23 The alternative<br />
is to continue vigorous efforts to reduce tobacco use, in<br />
the hope of achieving goals such as the Healthy People 2010<br />
target of 12% smoking prevalence among adults in the USA. 24<br />
Regulatory debates might benefit from understanding the likely<br />
public health consequences of displacing cigarettes with cleaner<br />
nicotine delivery systems. The US Centers for Disease Control<br />
and Prevention has contributed to tobacco policy debates with<br />
its series of SAMMEC (Smoking Attributable Morbidity,<br />
Mortality and Economic Costs) computer programs. 25–31<br />
This paper has two purposes. First, it introduces the<br />
DEMANDS program (Differences in Expected Mortality<br />
Adjusted for Nicotine Delivery Systems), a spreadsheet<br />
combining SAMMEC 3 data and methods with adjustable<br />
estimates of risk sources and exposures for the SAMMEC diseases.<br />
DEMANDS estimates the public health consequences of<br />
arbitrary combinations of cigarette smoking, with or without<br />
a competing PREP. Second, this paper contrasts the long term<br />
consequences of achieving the Healthy People 2010 goals with<br />
an alternative policy in which a clean, fast acting nicotine<br />
inhaler completely displaces tobacco cigarettes. Although this<br />
analysis highlights some questions about the safety of<br />
nicotine and acceptability of a nicotine inhaler, it also suggests<br />
that widespread use of clean nicotine inhalers could have tolerable<br />
public health consequences.<br />
METHODS<br />
Overview<br />
The DEMANDS program is an adaptation of SAMMEC 3.<br />
DEMANDS is limited to predicting changes in years of potential<br />
life lost before age 65 (YPLL65) and 85 (YPLL85) resulting<br />
from hypothetical shifts in the 1990 US’s population nicotine<br />
source and historical nicotine use. DEMANDS requires a user<br />
to make a number of assertions, including:<br />
(1) fraction of the population smoking cigarettes<br />
(2) fraction of the population using a PREP<br />
(3) PREP nicotine delivery<br />
(4) PREP smoke delivery<br />
(5) smoking harms attributable to nicotine, for each disease<br />
(6) smoking harms attributable to smoke, for each disease<br />
(7) smoking harms attributable to genes and environment,<br />
subsequently called correlates (of smoking), for each disease.<br />
From these data DEMANDS estimates relative risks for PREP<br />
users, then predicts the number of 1990 deaths that would<br />
have occurred in a given scenario.<br />
The current analysis explores the long term consequences<br />
of two tobacco control strategies. One strategy reaches the<br />
Healthy People 2010 goals for smoking. The second strategy<br />
would replace cigarettes with a clean nicotine delivery system.<br />
Each strategy is assumed to have established an equilibrium<br />
pattern of nicotine use after many years.<br />
DEMANDS software<br />
The DEMANDS program is a Microsoft Excel spreadsheet<br />
extending the mortality predictions of SAMMEC 3. DE-<br />
MANDS uses most of the data and methods of SAMMEC 3.<br />
SAMMEC 3 provides relative risk estimates for 27 tobacco<br />
related causes of death, adjusted for age, sex, and smoking<br />
status. SAMMEC 3 also provides data on the reported<br />
occurrence of deaths from these 27 tobacco related illnesses,<br />
and prevalence of smokers and ex-smokers in the USA in<br />
1990. From the prevalence of smoking, relative risks of death<br />
from diseases, and absolute numbers of deaths in each disease<br />
category, SAMMEC 3 estimates the number of deaths<br />
attributable to smoking. It then infers years of potential life<br />
lost (YPLL), economic losses, and smoking attributable<br />
mortality rates.<br />
DEMANDS predicts years of potential life gained or lost<br />
before ages 65 and 85 as a consequence of changes in safety<br />
and prevalence of nicotine use, using actual deaths in 1990 as<br />
a baseline.<br />
The key assumption in DEMANDS is that four distinguishable<br />
features of smoking and smokers cause tobacco related<br />
deaths. The first is nicotine, which is present in other nicotine<br />
delivery systems. The second is smoke, composed of thousands<br />
of gases and particulates. The third is carbon monoxide,<br />
distinguished from smoke because some PREPs deliver large<br />
quantities of this dangerous gas. The fourth is the collection of<br />
all correlates of smoking—for example, characteristics of<br />
smokers or ex-smokers that persist whether or not they<br />
smoke. Alcoholism, poverty, and psychiatric illness are examples<br />
of smoking correlates that could increase mortality from<br />
many diseases even if these patients never smoke. Many<br />
smokers who die of smoking related illnesses may have had<br />
concurrent problems that would have limited the benefits of<br />
smoking cessation. DEMANDS therefore requires the data<br />
described in the following sections.<br />
Nicotine use<br />
SAMMEC 3 defines nine populations of tobacco users. There<br />
are smokers and ex-smokers, males and females, aged 35–65<br />
years and over 65 years (2 × 2 × 2 = 8 combinations), and<br />
pregnant smokers. In place of SAMMEC 3’s description of the<br />
prevalence of smokers and ex-smokers, DEMANDS anticipates<br />
10 nicotine use categories. Dividing each category by sex,<br />
age, and pregnancy status yields 50 groups of nicotine users.<br />
DEMANDS requires a prevalence estimate for each of these<br />
groups. The nicotine use categories and their distinct<br />
collections of risks follow.<br />
Categories 1–4 reclassify SAMMEC 3 smokers.<br />
(1) Smokers smoke tobacco cigarettes. Smokers have the relative<br />
risks of current smokers. This category includes individuals<br />
using both a PREP and cigarettes.<br />
(2) Switchers stop using tobacco in favour of a PREP. Switchers<br />
share the correlate risks of smokers; nicotine, smoke, and carbon<br />
monoxide risks of the PREP, as applicable; and the smoke<br />
and carbon monoxide related risks of ex-smokers if the PREP<br />
does not deliver smoke or carbon monoxide.<br />
(3) Would-be smokers have used only the PREP, but would have<br />
used tobacco had the PREP been unavailable. Would-be<br />
smokers have the correlate risk of smokers, and the risks of<br />
the PREP.<br />
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126 Sumner<br />
(4) Prohibited smokers would have smoked cigarettes in 1990,<br />
but external events prevent them from ever using any nicotine<br />
product, including cigarettes. That is, some combination of<br />
taxation, education, social norms, sales restrictions, and<br />
smoking prohibitions could have prevented these people, who<br />
were smokers in 1990, from even experimenting with tobacco.<br />
They have only the correlate risks of smokers. Prohibited<br />
smokers (rather than ex-smokers) are required to model the<br />
long term reduction in smoking prevalence in the Healthy<br />
People 2010 scenario.<br />
Categories 5–8 reclassify SAMMEC 3 ex-smokers.<br />
(5) Ex-smokers stop using tobacco and do not use a PREP. They<br />
have the same relative risks as current ex-smokers.<br />
(6) Relapsers are ex-smokers who resume using nicotine when<br />
the PREP is available. Relapsers have the correlate risk of<br />
ex-smokers, the risks of the PREP, and the smoke and carbon<br />
monoxide related risks of ex-smokers if the PREP does not<br />
deliver smoke or carbon monoxide.<br />
(7) Would-be ex-smokers have used only the PREP, but would<br />
have used and quit tobacco had the PREP been unavailable.<br />
Would-be ex-smokers have the correlate risks of ex-smokers<br />
and the risks of the PREP.<br />
(8) Prohibited ex-smokers would have stopped using tobacco in<br />
1990, but external events prevent them from ever using any<br />
nicotine product. They have only the correlate risks of<br />
ex-smokers. In a long term Healthy People scenario, most current<br />
ex-smokers are reclassified as prohibited ex-smokers.<br />
Categories 9 and 10 reclassify SAMMEC 3 never-smokers.<br />
(9) New users would never use tobacco products, but do use a<br />
PREP. New PREP users experience the risks of the PREP.<br />
(10) Abstainers do not use any nicotine products, and have a<br />
relative risk of 1 for SAMMEC diseases.<br />
The current analysis assumes that achievement of Healthy<br />
People 2010 goals would include a reduction in smoking<br />
initiation, and therefore small numbers of ex-smokers in<br />
ensuing decades. The clean nicotine scenarios reclassify all<br />
smokers as would-be smokers or prohibited smokers; all exsmokers<br />
as would-be ex-smokers or prohibited ex-smokers, and all<br />
never-smokers as new users or abstainers. People like current<br />
smokers are assumed to use nicotine at lowest prevalence of<br />
use. People like current ex-smokers use nicotine if the prevalence<br />
is higher, and finally, current never-smokers use nicotine<br />
at the highest levels of use.<br />
Nicotine delivery system<br />
DEMANDS requires estimates of the nicotine, smoke, and<br />
carbon monoxide delivery of a new nicotine delivery system,<br />
as a multiple of what modern cigarettes deliver. In addition,<br />
because SAMMEC 3 simply lists absolute numbers of deaths<br />
from fires attributed to cigarettes, DEMANDS requires an<br />
estimate of the fire starting propensity of a new PREP, again as<br />
a multiple of the hazard posed by cigarettes. These variables<br />
would typically vary from zero (no nicotine source) to 100%<br />
(typical cigarettes in 1990) or more. For instance, one might<br />
guess that the Eclipse device delivers 90% of the nicotine, 10%<br />
of the smoke, 130% of the carbon monoxide, and have 20% of<br />
the fire starting propensity of a traditional cigarette. A clean<br />
nicotine inhaler would have 100% of the nicotine, and 0% of<br />
the smoke, carbon monoxide, and fire starting propensity of<br />
cigarettes.<br />
Relative risk fractions<br />
For each of 26 SAMMEC 3 diseases (excluding burns),<br />
DEMANDS requires estimates of the fraction of smokers’<br />
excess relative risk that is attributable to one of four general<br />
causes of illness: nicotine, carbon monoxide, smoke constituents<br />
other than nicotine and carbon monoxide, and smoking<br />
correlates. Attributing risks to smoking correlates reduces the<br />
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estimated benefits of switching nicotine source and smoking<br />
cessation relative to continued smoking. Attributing risks to<br />
nicotine increases the estimated mortality for ex-smokers and<br />
never-smokers who become PREP users, relative to exsmokers<br />
and never-smokers. Attributing risk to smoke and<br />
carbon monoxide increases the benefits of switching and<br />
smoking cessation, without adding risk for ex-smokers and<br />
never-smokers who become PREP users. Unlike some PREPs,<br />
a clean nicotine inhaler should not deliver carbon monoxide,<br />
therefore the current analysis will include carbon monoxide<br />
risks with smoke risks<br />
There is no direct evidence for these risk fraction estimates.<br />
Therefore, this analysis simply reports a range of possibilities<br />
relevant to regulation of a pulmonary inhaler delivering<br />
essentially pure nicotine. Four possibilities are considered.<br />
(1) 100% smoke (all excess relative risk is due to smoke or<br />
carbon monoxide)<br />
(2) 85% smoke, 10% correlates, 5% nicotine<br />
(3) 60% smoke, 30% correlates, 10% nicotine<br />
(4) 33% smoke, 33% correlates, 33% nicotine.<br />
An extreme scenario bounds the range of logical possibilities.<br />
Although inconsistent with available data, this boundary<br />
is useful for estimating other scenarios by rough interpolation.<br />
(5) Mathematical boundary: 100% nicotine.<br />
Predicted relative risks<br />
DEMANDS predicts the relative risk of a disease in a population<br />
as follows.<br />
(1) For each SAMMEC disease, multiply the estimated<br />
fraction of risk attributable to nicotine, smoke, or carbon<br />
monoxide with the fraction of that component delivered by<br />
the PREP.<br />
(2) Take the sum of these products and multiply by the excess<br />
risk (that is, the relative risk −1) of that disease in the relevant<br />
SAMMEC 3 population.<br />
(3) If the PREP does not deliver smoke and the PREP user<br />
stops smoking, then multiply the estimated fraction of risk<br />
attributable to smoke by the excess risk of the disease in<br />
ex-smokers, and add this value to the sum.<br />
(4) Add 1.<br />
For instance, consider a clean nicotine inhaler delivering<br />
100% of the nicotine, 0% of the smoke, and 0% of the carbon<br />
monoxide in a cigarette. Estimate that 10% of the excess risk<br />
of lung cancer is due to nicotine, 60% to carcinogens in smoke,<br />
0% from carbon monoxide, and 30% to correlates. SAMMEC 3<br />
estimates that 35–40 year old male smokers and ex-smokers<br />
have relative risks of 22.36 and 9.36, respectively, for developing<br />
lung cancer compared to never-smokers. In a smoker who<br />
switches to the clean nicotine inhaler, the relative risk of fatal<br />
lung cancer falls to:<br />
1 + ((1 × 0.1) nicotine +(0×0.6) smoke +(0×0) CO + 0.3 correlate)<br />
× (22.36 − 1) smoker excess risk + (0.6 × (9.36−1)) ex-smoker risk =<br />
14.56<br />
The decline in risk is modest because smoking correlates<br />
and nicotine exposure persist, and switchers continue to<br />
experience the risks of ex-smokers. For never-smokers who<br />
begin using a clean nicotine inhaler, lung cancer risk climbs<br />
from 1.0 to 1 + (1 × 0.1) × (22.36 − 1) = 3.136.<br />
Death multiplier<br />
The formula below predicts a multiple of deaths expected from<br />
a new pattern of use of a nicotine delivery system, relative to<br />
the 1990 experience with cigarette smoking:<br />
Multiple = (Sum for i=1 to 10(P i*RR i))/(P n +P s*RR s +P x*RR x)
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Replacing cigarettes with nicotine inhalers 127<br />
where Pi = expected prevalence of the i th DEMANDS class of<br />
nicotine users<br />
RRi = calculated relative risk of the i th DEMANDS class of<br />
nicotine users<br />
Pn = 1990 prevalence of never-smokers<br />
Ps = 1990 prevalence of smokers<br />
Px = 1990 prevalence of ex-smokers<br />
RRs = relative risk in smokers<br />
RRx = relative risk in ex-smokers<br />
Changes in YPLL<br />
Multiplying the number of deaths documented in 1990 by the<br />
multiplier calculated above yields the number of deaths in a<br />
given cohort. The change in deaths in that cohort is the difference<br />
between the 1990 observation and the prediction. If the<br />
change is positive (the death multiplier is less than 1), then<br />
DEMANDS subjects new survivors to general mortality risks<br />
in this and ensuing years. DEMANDS uses 1993 estimates of<br />
age and sex specific death rates to estimate these deaths.<br />
Finally, DEMANDS calculates the difference between observed<br />
total YPLL65 and YPLL85 in 1990 from the 27 SAMMEC diseases<br />
and total YPLL85 predicted after a change in nicotine<br />
use.<br />
Scenarios examined<br />
The four risk attribution scenarios were combined with steady<br />
state nicotine use scenarios. These steady state use scenarios<br />
model a constant pattern of nicotine use over many decades,<br />
rather than the fluctuating use of cigarettes seen during the<br />
1900s. Clean nicotine inhaler scenarios model use by 0–100%<br />
of adults, in 10% increments, with no cigarette use so that<br />
smokers and ex-smokers are non-existent. The four risk attribution<br />
scenarios also were compared to a steady state<br />
achievement of the Healthy People 2010 goal of 12% smoking<br />
prevalence, assuming a 5% prevalence of ex-smokers (again<br />
assuming a steady, long established pattern of smoking). The<br />
changes in years of potential life lost before age 65 and 85,<br />
relative to actual 1990 experience, were calculated as a<br />
function of the prevalence of clean nicotine inhaler use. The<br />
years of potential life gained or lost before age 85, relative to<br />
Healthy People 2010 goals, was calculated as a function of the<br />
prevalence of clean nicotine inhaler use.<br />
I will refer to reductions in years of potential life lost as<br />
“years of potential life gained” (YPLG) to avoid double negative<br />
phrases. A positive YPLG is a public health gain, meaning<br />
that a year of potential life lost in 1990 would not have been<br />
lost in the reported scenario. A negative YPLG is a public<br />
health loss, meaning that a year of life that was not lost in<br />
1990 is lost in the scenario.<br />
RESULTS<br />
Years of potential life gained or lost at steady state<br />
Figure 1 illustrates the years of potential life gained before age<br />
65 (YPLG 65) as a function of prevalence of use of a clean<br />
nicotine inhaler, for four different assumptions about risk<br />
attribution. If all excess risk were attributable to smoke rather<br />
than nicotine or correlates of smoking, then DEMANDS estimates<br />
that all levels of inhaler use yield about one million<br />
YPLG 65. Assigning a large amount of risk to nicotine causes<br />
net harms with high levels of nicotine use. For example, if two<br />
thirds of adults would use a clean nicotine inhaler, and nicotine,<br />
smoke, and correlates each accounted for one third of the<br />
excess risk of each SAMMEC disease, then there would be no<br />
public health benefit to adopting inhalers instead of maintaining<br />
1990 smoking patterns.<br />
Figure 2 provides the same data for YPLG 85. The prevalence<br />
of steady state nicotine inhaler use that is neutral for this<br />
measure of public health is about 76%, slightly higher than in<br />
fig 1.<br />
Figure 1 Changes in years of potential life before age 65 if<br />
nicotine inhalers displaced cigarettes, relative to the 1990 SAMMEC<br />
estimate of YPLL65. Interpolation between the 100% smoke line and<br />
the mathematical limit (hypothetical 100% of risk from nicotine)<br />
yields any risk attribution scenario with 0% of risk due to correlates.<br />
For example, at 100% prevalence of nicotine use, the vertical<br />
distance from the 100% smoke value to the baseline is about 30% of<br />
the distance from 100% smoke to the mathematical limit. This<br />
indicates that if 100% of the population uses a clean nicotine<br />
inhaler, if nicotine uniformly accounts for 30% of smoker’s excess<br />
risk, and if correlates of smoking are irrelevant, then the public<br />
health consequences are equivalent to the actual 1990 experience.<br />
Figure 2 Changes in years of potential life before age 85 if<br />
nicotine inhalers displaced cigarettes, relative to the 1990 SAMMEC<br />
estimate of YPLL85.<br />
Figure 3 again estimates YPLG 85 for different levels of<br />
clean nicotine inhaler use, but assumes steady state Healthy<br />
People 2010 goals as the baseline (12% cigarette smoking<br />
prevalence, with 5% ex-smoking). In each risk scenario,<br />
DEMANDS predictions for Healthy People goals in that risk<br />
scenario are subtracted from the clean nicotine inhaler<br />
predictions, so that 0 on the y axis always represents parity<br />
with Healthy People 2010. DEMANDS predictions for Healthy<br />
People scenarios (versus 1990) vary from 2–4 million YPLG.<br />
When compared to a Healthy People scenario, nicotine inhaler<br />
use can be quite prevalent and still yield public health benefits<br />
unless nicotine accounts for more than about one third of risk.<br />
However, if nicotine users experience less risk, then very<br />
widespread inhaler use looks preferable to Healthy People<br />
2010 goals.<br />
Causes of deaths<br />
Table 1 lists the numbers of deaths DEMANDS predicts for<br />
each SAMMEC disease, assuming 50% PREP prevalence and<br />
the four risk scenarios. The overwhelmingly important<br />
contributors to premature death are coronary artery disease,<br />
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128 Sumner<br />
Figure 3 Changes in years of potential life before age 85 if<br />
nicotine inhalers displaced cigarettes, relative to the DEMANDS<br />
estimate of YPLL85 after achieving Healthy People 2010 goals.<br />
respiratory tract cancer, and chronic obstructive pulmonary<br />
disease. Consequently, the most important risk attributions<br />
involve these three classifications. Other cardiovascular, infectious,<br />
malignant, and childhood diseases and burns contribute<br />
far fewer deaths.<br />
One can approximate mixed risk attribution models from<br />
table 1. For each SAMMEC disease, select the column that<br />
Table 1 Scenario descriptions<br />
most closely approximates expectations. For example, one<br />
might expect that pulmonary diseases are 100% attributable<br />
to smoke; that malignancies are 80% attributable to smoke,<br />
15% attributable to correlates, and 5% attributable to nicotine.<br />
The model estimates that 50% prevalence of clean nicotine use<br />
results in 57 000 YPLL85 from asthma, compared to 73 000 in<br />
1990, yielding a public health gain of 16 000 YPLG85 for mortality<br />
averted from this disease. Adding gains and losses<br />
calculated from the columns that best describe risk attribution<br />
for each disease yields an estimate of total change in YPLG85<br />
for 50% use of a clean nicotine inhaler in the specified risk<br />
attribution model, relative to the actual 1990 experience.<br />
DISCUSSION<br />
The DEMANDS program describes a process for extending<br />
SAMMEC methodology and data to estimate the public health<br />
consequences of a PREP competing with cigarettes in the<br />
marketplace. In the current analysis, DEMANDS was used to<br />
estimate the public health consequences of completely<br />
displacing cigarettes with a clean nicotine inhaler. Although<br />
the correct risk attribution is not known, nicotine probably<br />
accounts for much less than a third of smokers’ risk for most<br />
of the SAMMEC diseases. At this level of risk, displacement of<br />
tobacco products with clean nicotine delivery systems should<br />
yield public health benefits comparable or superior to the benefits<br />
of reaching and maintaining Healthy People 2010 goals in<br />
the USA, even if the prevalence of nicotine use in the USA rose<br />
Prevalence Actual 1990* 50% 50% 50% 50%<br />
Nicotine source Cigarettes Inhaler Inhaler Inhaler Inhaler<br />
Risk from smoke NA 100 85 60 33<br />
Risk from covariates NA 0 15 30 33<br />
Risk from nicotine NA 0 5 10 33<br />
Disease specific YPLL85 (’000s)<br />
ICD-9 Disease<br />
Tuberculosis<br />
10–12 Respiratory tuberculosis 22 15 16 18 20<br />
Cancers of:<br />
140–149 Lip, oral cavity, pharynx 146 26 52 78 119<br />
150 Oesophagus 164 39 65 91 128<br />
157 Pancreas 342 239 262 285 322<br />
161 Larynx 65 12 23 34 50<br />
162 Trachea, lung, bronchus 2315 339 765 1192 1866<br />
180 Cervix uteri 102 72 79 85 96<br />
188 Urinary bladder 104 58 67 76 90<br />
189 Kidney, other urinary 160 104 116 128 144<br />
Cardiovascular diseases<br />
390-398 Heart valve disease 79 63 67 70 76<br />
401-404 Hypertension 355 277 294 311 339<br />
410-414 Ischaemic heart disease 4700 3252 3561 3870 4350<br />
415-417 Pulmonary heart disease 155 121 128 136 148<br />
420-429 Other heart disease 1773 1359 1448 1536 1675<br />
430-438 Cerebrovascular disease 1136 757 843 929 1079<br />
440 Atherosclerosis 79 61 64 68 75<br />
441 Aortic aneurysm 175 82 101 121 149<br />
442-448 Other arterial disease 81 42 50 59 72<br />
Adult pulmonary diseases<br />
480-487 Pneumonia and influenza 491 339 371 403 451<br />
490-492 Bronchitis, emphysema 214 40 75 110 158<br />
493 Asthma 73 53 57 62 69<br />
496 Chronic airway obstruction, NOS 627 114 217 320 457<br />
Newborn and infant diseases<br />
765 Short gestation/low birth weight 341 298 310 336 350<br />
769 Respiratory distress syndrome 243 212 220 239 249<br />
770 Respiratory conditions of the newborn 252 220 228 248 258<br />
798 Sudden infant death syndrome 461 403 418 454 472<br />
Burns<br />
890-899 Burns 49 0 0 0 0<br />
Total YPLL85<br />
Scenario column sum 14702 8595 9901 11260 13263<br />
Healthy People 2000 steady state prediction* 11304 11810 12309 12429<br />
Healthy People 2010 steady state prediction* 10822 11399 11965 12106<br />
*Steady state scenarios assume a longstanding equilibrium in nicotine use, rather than a market fluctuating over a decade or two.<br />
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Replacing cigarettes with nicotine inhalers 129<br />
to two or three times the current prevalence of cigarette<br />
smoking. If nicotine accounts for 5% or less of cigarette smokers’<br />
risks, then a clean nicotine inhaler that displaces<br />
cigarettes results in much greater public health gains than<br />
Healthy People 2010 goals would produce, regardless of the<br />
prevalence of nicotine use. On average, eight nicotine users<br />
may be healthier than one smoker and seven non-smokers.<br />
For smokers and clinicians, the most attractive feature of a<br />
clean nicotine inhaler is that it could provide most of the benefits<br />
of smoking cessation to patients who are otherwise least<br />
likely to stop using deadly tobacco products. No other tobacco<br />
control policy offers this hope.<br />
This analysis makes several assumptions unfavourable to<br />
the clean nicotine inhaler. First, the prevalence of nicotine use<br />
among pregnant women is assumed to equal that in young<br />
women. The model therefore exaggerates the deleterious perinatal<br />
effects of nicotine because some pregnant women will<br />
abstain from nicotine as they do from cigarettes. Second,<br />
DEMANDS assumes no changes in overall death rates with<br />
widespread nicotine inhaler use. Deaths avoided at an early<br />
age are redistributed according to currently observed death<br />
rates. In reality, avoidance of early smoking induced deaths<br />
should shift the distribution of all deaths later into life, resulting<br />
in greater benefits. Third, DEMANDS does not quantify<br />
never-smokers’ mortality benefit from elimination of environmental<br />
tobacco smoke, which may total tens of thousands of<br />
YPLL85. This benefit would be larger in nicotine inhaler<br />
scenarios, which eliminate environmental smoke, than in the<br />
Healthy People 2010 scenario, which continues to expose some<br />
non-smokers to environmental smoke. The benefits of a clean<br />
nicotine inhaler that displaces cigarettes might be larger than<br />
this analysis predicts.<br />
In spite of the general finding that public health might<br />
benefit equally from achieving Healthy People 2010 goals as<br />
from widely used, clean, fast acting nicotine inhalers, nicotine<br />
remains a drug deserving of some government regulation.<br />
Deeply inhaled nicotine may addict users just as efficiently as<br />
cigarettes. The decision making errors of youths and rationalisations<br />
of adults will persist. 32 At the very least, consumers<br />
should know of nicotine’s potential immunosuppressive<br />
effects, 33 the possibility that nicotine is a gateway to drug and<br />
alcohol abuse, 34 35 and the high probability that nicotine<br />
permanently affects fetal brain development. 36–43 Publicising<br />
these risks should dissuade many potential users, especially<br />
during pregnancy. If nicotine inhalers displace cigarettes<br />
without increasing overall nicotine use, then DEMANDS consistently<br />
predicts greater public health gains than Healthy<br />
People 2010 achievements would deliver.<br />
Making the switch<br />
Although public health gains might be similar, the efforts<br />
required to achieve Healthy People 2010 goals may be quite<br />
different than those required to displace cigarettes with clean<br />
nicotine. Achieving Healthy People goals may require indefinite<br />
public investment in intense smoking cessation and prevention<br />
interventions, as advocated by the Centers for Disease<br />
Control report on best tobacco control practices. 44 Such efforts<br />
are difficult to initiate or maintain, as governments routinely<br />
divert funds from tobacco control. 45 46 If a novel, publicly<br />
funded tobacco control programme did dramatically reduce<br />
smoking it might also reduce tobacco tax revenues and<br />
become a net short term cost to the governments involved.<br />
Non-smoking voters seldom insist that their governments<br />
adhere to plans to spend tobacco tax revenue on tobacco control.<br />
These taxpayers may be even less likely to raise their own<br />
expenses to subsidise tobacco control. Furthermore, the<br />
formula for such dramatic success is elusive. It is not clear that<br />
the 2010 goal is achievable at all 47 48 or that all states or countries<br />
have the political will to achieve even the Healthy People<br />
2000 goal of 15% smoking prevalence. The Centers for Disease<br />
Control reports that only Utah achieved that goal, with 12.9%<br />
of adults reporting smoking. 49 Adult smoking was more common<br />
in California (17.8%), Minnesota (19.8%), Massachusetts<br />
(20.0%), and Oregon (20.8%), in spite of these states’ tobacco<br />
control programmes. In 2002, 16.9% of US high school seniors<br />
smoked cigarettes daily, slightly below the previous nadir of<br />
17.2% in 1992. 50 While this is a welcome improvement over the<br />
mid 1990s, it would be premature to conclude that Healthy<br />
People 2010 goals are within reach.<br />
In contrast, a tobacco control policy that includes a clean<br />
nicotine alternative to cigarettes requires legislative support,<br />
but less commitment of public resources and less innovation<br />
in tobacco control methods. The first policy step would be to<br />
allow the pharmaceutical industry to privately develop and<br />
market increasingly clean and fast acting nicotine delivery<br />
systems—for example, adapting an existing metred dose<br />
powder inhaler or adopting the design patented by Rose and<br />
colleagues. 18 Policies to encourage substitution of nicotine<br />
inhalers for cigarettes would reflect established principles of<br />
community level tobacco control policy, such as raising<br />
tobacco product prices, informing consumers of risks, counter<br />
advertising, restricting youth access and marketing, and limiting<br />
opportunities to smoke. 44 Taxation and product liability<br />
costs are already raising the price of cigarettes, and could create<br />
a significant price difference between cigarettes and less<br />
hazardous nicotine delivery systems. Governments should tax<br />
all nicotine delivery devices at rates that at least recover their<br />
regulatory and health costs. Governments would then tax<br />
safer nicotine products at a lower rate than hazardous tobacco<br />
products. 6 Legislation could shield the nicotine and tobacco<br />
industries from liability for the health effects of nicotine use,<br />
on the theory that even addicted individuals bear some<br />
responsibility to weigh the known risks against the perceived<br />
benefits of nicotine, 51 and in recognition of the historical futility<br />
of efforts to fully eradicate nicotine use. 52 However, the<br />
same legislation should recognise that corporations could best<br />
anticipate, control, and manipulate perceptions of the harms<br />
inherent in their nicotine delivery systems. Legislation<br />
holding companies accountable for these harms could<br />
maintain higher liability costs for cigarettes than for clean<br />
inhalers. Labels on all nicotine products should inform<br />
consumers of risks, including addiction, and enumerate the<br />
products’ chemical constituents. Product specific labels on<br />
cigarettes will list more chemicals and carry more warnings<br />
than the labels on clean nicotine inhalers.<br />
As a special form of counter-advertising, legislation could<br />
permit promotion of clean nicotine delivery systems as an<br />
alternative to cigarettes, perhaps with fewer constraints than<br />
we apply to tobacco products. As with tobacco pipes and cigarette<br />
packages, the nicotine industry could produce myriad<br />
variations in the appearance of inhalers, so that users could<br />
select inhaler designs based on image. These images might<br />
even replicate successful smoking themes, such as rugged<br />
individuality, suave character, and pleasure. Pharmaceutical<br />
companies would then promote the images and real advantages<br />
of a modern nicotine inhaler to potential users,<br />
beginning with current smokers. Obviously, the government<br />
should continue to prohibit sales of all nicotine delivery<br />
systems, including clean inhalers, to young people. The<br />
government should monitor nicotine promotion in general, as<br />
corporations will wish to overstate the benefits of clean nicotine<br />
products. Local ordinances that curtail public smoking<br />
already create settings where a nicotine inhaler could be the<br />
most satisfying alternative for current smokers. Lacking a<br />
burning tip and side stream smoke, an inhaler should present<br />
no risk to bystanders, and requires no restriction on public<br />
use. Employers could even abolish outdoor smoking areas and<br />
smoking breaks if addicted employees could inhale nicotine<br />
indoors. Thus, nicotine inhalers would offer a valuable health<br />
benefit to current smokers, and rational policies based on<br />
established tobacco control principles could promote nicotine<br />
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130 Sumner<br />
inhaler market share at the expense of cigarettes. These policies<br />
may be politically difficult to enact. Nevertheless, these<br />
policies require little public investment, might accelerate the<br />
contraction of the cigarette market, and should reduce or<br />
delay public health care costs to the extent that they promote<br />
inhaler use in place of cigarette smoking.<br />
Some undesirable public health scenarios might unfold if a<br />
clean nicotine inhaler did not succeed in replacing tobacco<br />
cigarettes. First, the inhaler could simply disappear from the<br />
market, leaving the prevalence of cigarette use and nicotine<br />
addiction unchanged or even increased. Second, the inhaler<br />
could recruit new users, but not replace enough cigarette<br />
smoking to offset harms to the new users. However, even this<br />
short term public health failure would create legislative<br />
opportunities to demand lower nicotine content in cigarettes<br />
while raising cigarette taxes aggressively. 653 Relatively satisfying<br />
inhalers could then supplant expensive and unsatisfying<br />
cigarettes and provide an alternative to black market cigarette<br />
purchases. 54<br />
Other potential nicotine hazards<br />
The net public health effect of allowing a clean, fast nicotine<br />
delivery system to compete with cigarettes is less certain than<br />
the obvious benefit of reducing all nicotine and tobacco use.<br />
Mathematical models would benefit from accurate estimates<br />
of risk attribution. The only certain approach to acquiring<br />
these data would require offering a palatable and inexpensive<br />
nicotine inhaler to a population of potential users (including<br />
never-smokers), then describing their experience. There may<br />
be no practical means of conducting a well controlled experiment<br />
of this sort.<br />
However, we might be able to develop estimates of nicotine<br />
risks from other data. For example, smokeless tobacco users’<br />
relative risks for 26 SAMMEC 3 disease categories (excluding<br />
burns) provide an initial estimate for the sum of the risk fractions<br />
attributable to nicotine and correlates. Smokeless<br />
tobacco users’ risks for many of these diseases may be<br />
available through analysis of existing data sets. Even slightly<br />
elevated risks of SAMMEC 3 diseases among smokeless<br />
tobacco users would deserve investigation before a policy shift<br />
that might increase use of nicotine in the general population.<br />
Cardiovascular disease is a particular concern. Exposing<br />
large segments of the population to increased risks of ischaemic<br />
heart disease could overwhelm other health gains. As<br />
shown in table 1, SAMMEC 3 counts more YPLL85 from<br />
cardiovascular diseases than from any other cause. Consequently,<br />
small changes in risks for cardiovascular disease,<br />
especially ischaemic heart disease, substantially change<br />
DEMANDS predictions. However, nicotine would need to<br />
account for 30% or more of smokers’ excess risk of cardiovascular<br />
diseases before DEMANDS would project a significant<br />
possibility of public health losses compared to 1990. This<br />
seems quite unlikely given the safety of nicotine replacement<br />
in the Lung Health Study, and among patients with<br />
established coronary artery disease. 55–59<br />
Although nicotine replacement therapy is generally free of<br />
serious adverse consequences, 60 nicotine might induce fatal<br />
diseases not anticipated by SAMMEC software. Nicotine<br />
causes a distinct acute toxicity syndrome typified by green<br />
tobacco sickness. 61 62 However, nicotine poisoning deaths are<br />
remarkably unlikely in tobacco harvesters, children ingesting<br />
nicotine or tobacco, 63 or adults attempting suicide with<br />
nicotine patches. 64 If nicotine use were to increase other substance<br />
abuse, then a clean nicotine inhaler could lead to<br />
increased deaths from alcohol and drug abuse. Current literature<br />
may not have explored complex pathways leading from<br />
nicotine use to human death. For instance, Heeschen and colleagues<br />
report that nicotine is angiogenic, 65 and might<br />
promote tumour growth, but even this hypothetical harm<br />
might be offset by accelerated wound healing. 66 Synergism<br />
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What this paper adds<br />
Pharmaceutical grade nicotine replacement products are<br />
far safer than tobacco products, while novel tobacco<br />
products have uncertain risk profiles. The SAMMEC 3<br />
(Smoking Attributable Morbidity, Mortality and Economic<br />
Costs) software from the US Centers for Disease Control<br />
and Prevention is a widely accepted model for estimating<br />
the number of deaths caused by cigarette smoking. However,<br />
SAMMEC 3 software cannot predict the health<br />
effects of a marketplace where cigarettes compete with, or<br />
are displaced by, potentially safer nicotine delivery<br />
systems.<br />
A new computer program, DEMANDS (Differences in<br />
Expected Mortality Adjusted for Nicotine Delivery Systems),<br />
extends SAMMEC methods to estimate the health<br />
consequences of a marketplace where cigarettes compete<br />
with another nicotine delivery system. Adjustable DE-<br />
MANDS inputs include the prevalence of smoking and<br />
other nicotine use, smoke and carbon monoxide delivery<br />
by the alternative system, and proportions of disease specific<br />
risks arising from nicotine, smoke, and carbon<br />
monoxide. For a wide range of plausible inputs,<br />
DEMANDS estimates that the health consequences of completely<br />
displacing cigarettes with a widely used, deeply<br />
inhaled, highly addictive, pharmaceutical grade nicotine<br />
inhaler are comparable or superior to reducing smoking<br />
prevalence to 12%. Public health advocates and pharmaceutical<br />
companies could adapt tobacco control techniques<br />
to encourage smokers to replace cigarettes with<br />
nicotine inhalers. Nicotine inhalers might improve public<br />
health regardless of the political or economic fortunes of<br />
other tobacco control initiatives.<br />
between nicotine and environmental risk factors other than<br />
cigarettes is conceivable. For example, chronic exposure to<br />
pure nicotine and polluted air might cause chronic obstructive<br />
lung disease.<br />
DEMANDS does not estimate morbidity from nicotine use.<br />
Nicotine might impair quality of life or productivity by altering<br />
growth and function of the nervous system, with consequences<br />
potentially including depression, anxiety or<br />
addiction. 8 These require further elaboration, separate analysis,<br />
and disclosure to smokers and other potential nicotine<br />
users.<br />
Although a number of animal studies suggest negative<br />
health consequences for nicotine consumption, 67–72 others<br />
seem to exonerate nicotine as a major cause of cardiopulmonary<br />
and other diseases. 73–75 Modestly immunosuppressive nicotine<br />
could reduce an animal’s resistance to infection by<br />
viruses, bacteria or mycobacteria. 33 The effects of nicotine on<br />
fetal development need further investigation. 76<br />
Limitations<br />
DEMANDS predicts consequences of nicotine use by extending<br />
the data and methods used in SAMMEC 3 software.<br />
DEMANDS therefore shares any inaccuracies present in<br />
SAMMEC 3 data or methods. SAMMEC 3 implicitly assumes<br />
that embedded relative risk data fairly represent smoking<br />
risks, and do not hide correlate risks. The relative risk data<br />
originate from the American Cancer Society Cancer Prevention<br />
Survey II, in which society volunteers chose families to<br />
follow for six years. 77 Smoking correlates such as mental<br />
illness and poverty might be scarce in this population, reducing<br />
the need to estimate correlate risk fractions. Recent analyses<br />
suggest that relative risks for the most important tobacco<br />
related illnesses do not require adjustment for several<br />
potential correlate risks, including education, occupation,<br />
race, alcohol consumption, various dietary factors, hyper-<br />
78 79<br />
tension, and diabetes.
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Replacing cigarettes with nicotine inhalers 131<br />
This report compares the consequences of steady state consumption<br />
of nicotine from one defined source, and therefore<br />
predicts the consequences of lifelong use of that source. The<br />
benefits of clean nicotine inhalers during a transitional period<br />
are more modest, because many users suffer from previous<br />
exposure to smoke. Likewise, in the year 2010, the immediate<br />
benefits of achieving Healthy People 2010 goals would be less<br />
dramatic than the benefits following decades of maintaining<br />
12% smoking prevalence. Similarly, a clean nicotine inhaler<br />
that partially displaces cigarettes would confer more modest<br />
public health benefits.<br />
Conclusion<br />
Prevention of tobacco use is historically difficult in spite of<br />
clear health hazards. Regulatory responses to the problem are<br />
tenuous and subject to reversal or delay as political and<br />
economic fortunes change. A lasting reduction in tobacco<br />
related illness might result from unleashing clean alternative<br />
nicotine delivery systems to compete directly with tobacco<br />
products. Even if used very broadly, clean inhaled nicotine<br />
might reduce public health problems as much as a very<br />
successful tobacco control programme. Additional research<br />
should attempt to quantify the health consequences of using<br />
pure nicotine. Meanwhile, clinical and marketing trials of<br />
clean nicotine inhalers are defensible in populations with a<br />
high burden of smoking related illness.<br />
ACKNOWLEDGEMENTS<br />
I would like to thank Gary Giovino and anonymous reviewers for<br />
patient and astute critiques that greatly improved this paper.<br />
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Estimating the health consequences of<br />
replacing cigarettes with nicotine inhalers<br />
W Sumner II<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
2 Saliva cotinine levels in users of electronic cigarettes
Eur Respir J 2011; 38: 1219–1236<br />
DOI: 10.1183/09031936.00066011<br />
CopyrightßERS 2011<br />
LETTERS<br />
Saliva cotinine levels in users of electronic cigarettes<br />
To the Editors:<br />
Electronic nicotine delivery systems (ENDS or electronic<br />
cigarettes) look like cigarettes but do not contain or burn<br />
tobacco. Instead, they comprise a battery-powered atomiser<br />
that produces a vapour for inhalation from cartridges containing<br />
humectants (propylene glycol or glycerol), flavours<br />
(e.g. tobacco, mint or fruit) and nicotine. Many smokers report<br />
using ENDS to quit smoking or to substitute for tobacco in<br />
smoke-free places [1, 2].<br />
ENDS do attenuate craving for tobacco, but appear to deliver<br />
little nicotine to the blood [3, 4]. Two studies have evaluated<br />
nicotine administration with different ENDS brands in ENDSnaïve<br />
smokers [3, 4]. In one study, 32 smokers completed two<br />
10-puff ‘‘vaping’’ bouts or smoked a cigarette [3]. In contrast to<br />
tobacco cigarettes, ENDS did not increase plasma nicotine<br />
reliably (plasma nicotine: 1.4 ng?mL -1 and 0.5 ng?mL -1 , respectively,<br />
for two ENDS brands). In the other study, smokers used<br />
ENDS with a 16-mg nicotine cartridge for 5 min, a nicotine<br />
inhaler for 20 min or their usual cigarette for 5 min [4]. Nicotine<br />
concentration in plasma, measured after 60 min, was 1.3 ng?mL -1<br />
for ENDS, 2.1 ng?mL -1 for inhalers and 13.4 ng?mL -1 for tobacco<br />
cigarettes, but one-third of participants showed no increase in<br />
blood nicotine while using the ENDS [4]. The time to maximum<br />
concentration of serum nicotine was shorter for ENDS (19.6 min)<br />
than for the nicotine inhaler (32.0 min), suggesting some absorption<br />
via the respiratory tract [4]. It is possible that serum nicotine<br />
levels would have been similar in ENDS and inhaler users, had<br />
ENDS users been allowed to use the devices for 20 min as for the<br />
inhaler.<br />
However, regular ENDS users may draw 120–175 puffs?day -1<br />
on average [1, 2], which is substantially more than the exposure<br />
levels used in these laboratory studies. To date, nicotine or<br />
cotinine (a metabolite of nicotine) have not been measured in<br />
experienced ENDS users. The assessment of whether ENDS actually<br />
deliver nicotine to users is crucial for regulation, for abuse<br />
liability assessment and to indicate whether ENDS have potential<br />
as smoking cessation aids. We therefore sought to measure<br />
cotinine in the saliva of experienced ENDS users contacted in<br />
real-life settings.<br />
Because ENDS are purchased mainly on the internet [1, 2], we<br />
posted a questionnaire in English and French on the smoking<br />
cessation website Stop-Tabac.ch between September 2010 and<br />
January 2011. We asked discussion forums and websites<br />
informing about ENDS or selling them to publish links to the<br />
survey (http://www.stop-tabac.ch/fr_hon/ECIG_EN). The online<br />
questionnaire covered ENDS use (current/past and duration),<br />
smoking status, age, sex and postal address. Current ENDS<br />
users were sent by mail a plastic vial, a consent form and an<br />
additional questionnaire on paper, which covered ENDS use<br />
(days per week), brand and model, whether their current ENDS<br />
contained nicotine, nicotine dosage, puffs?day -1 , refills?day -1 ,<br />
tobacco cigarettes per day (in smokers), quit date (in ex-smokers)<br />
and any tobacco, nicotine replacement therapy (NRT) and ENDS<br />
use in the previous 48 h. Participants were aged .18 yrs and the<br />
study was approved by the ethics committee of the Geneva<br />
University Hospitals (Geneva, Switzerland).<br />
Participants were instructed to collect the saliva samples no<br />
less than 30 min after eating or drinking, using the provided<br />
plastic vial which contained a small cotton roll similar to those<br />
used by dentists (Salivette; Sarstedt, Nümbrecht, Germany).<br />
They were asked to chew the cotton roll for 1 min then replace<br />
it in the vial and return it to us by mail. Upon receipt, vials<br />
were stored at -4uC for a few days and then shipped by express<br />
mail to ABS Laboratories (Welwyn Garden City, UK) for<br />
cotinine analysis by gas chromatography.<br />
We posted vials to the 196 current ENDS users and received 31<br />
vials back (a 16% response rate). The median age of the 31 participants<br />
was 41 yrs and most (65%) were males. The distribution<br />
of respondents by country was: USA (n518), France<br />
(n54), UK (n54), Switzerland (n53), Canada and Italy (n51<br />
each). Most participants (30 out of 31, 97%) were former<br />
smokers who had not smoked in the previous 48 h. There was<br />
one occasional smoker who was currently trying to quit and<br />
smoked one cigarette?day -1 . Former smokers had been abstinent<br />
for a median 4.2 months (25th and 75th percentiles:<br />
49 days and 10.5 months, range 20 days–2 yrs). No participant<br />
reported using NRT or smokeless tobacco in the 48 h prior to<br />
saliva collection.<br />
All participants but one used ENDS daily. Participants puffed<br />
a median of 200 times?day -1 on their ENDS (25th and 75th<br />
percentiles: 100 and 400 puffs?day -1 , range 50–1,000 puffs?day -1 ,<br />
mean¡SD 250¡205 puffs?day -1 ). The most used brands were<br />
Joye (n59, 29%) and Janty (n54, 13%), and the most used models,<br />
sold under different brand names, were Ego (n512, 39%) and 510<br />
(n57, 23%). On average, the concentration of nicotine in refill<br />
liquids was 18 mg?mL -1 , and participants used five refills or<br />
cartridges per day. At the time of saliva collection, participants<br />
had been using ENDS for a median of 94 days (25th and 75th<br />
percentiles: 45 days and 10 months, range 16 days–3 yrs).<br />
In the 30 ENDS users who, in the previous 48 h, had not used<br />
tobacco or NRT but had used ENDS, median cotinine level was<br />
322 ng?mL -1 (25th and 75th percentiles: 138 and 546 ng?mL -1 ,<br />
range 13–852 ng?mL -1 , mean¡SD 338¡227 ng?mL -1 ), and correlation<br />
between cotinine and puffs?day -1 on ENDS was r50.39<br />
(15% of variance explained, p50.034). The only smoker drew<br />
150 puffs?day -1 on his ENDS and had 141 ng?mL -1 cotinine. The<br />
only non-daily user used ENDS on 2 days?week -1 and had<br />
13 ng?mL -1 cotinine.<br />
We found substantial amounts of cotinine in the saliva of<br />
ENDS users. These results contrast with two laboratory reports<br />
EUROPEAN RESPIRATORY JOURNAL VOLUME 38 NUMBER 5 1219<br />
c
that concluded that ENDS did not reliably increase blood nicotine<br />
levels [3], or provided lower levels than nicotine inhalers or<br />
tobacco cigarettes [4]. The differences with our study may be<br />
explained by different durations of exposure, users’ experience<br />
with the devices, puffing characteristics, models used and the<br />
swallowing of nicotine. In our study, experienced users puffed<br />
intensively and had been using ENDS regularly for months,<br />
whereas the previous studies were conducted in ENDS-naïve<br />
users. Experience with the device is likely to have influenced<br />
blood nicotine/cotinine levels. The correlation between puff<br />
number and cotinine suggests that puffing topography is an<br />
important factor that should be controlled for in future studies.<br />
Furthermore, in our study, participants used some of the most<br />
popular brands and models identified in user surveys [1, 2],<br />
whereas those tested in previous studies may be less popular, and<br />
it is possible that the models used in this study delivered more<br />
nicotine than those previously tested. ENDS users may swallow<br />
some of the nicotine, thus removing it from the circulation and<br />
submitting it to first-pass metabolism in the liver. Thus, it may be<br />
difficult to compare studies that assess nicotine with those that<br />
assess cotinine, and it may also be difficult to compare cotinine<br />
levels in ENDS users, nicotine patch users and smokers.<br />
However, a substantial part of the nicotine in oral forms of NRT<br />
is also swallowed [5].<br />
Nevertheless, cotinine levels in ENDS users were similar to<br />
levels previously observed in smokers [6] and higher than<br />
levels previously found in NRT users [7, 8]. Cotinine levels are<br />
roughly similar when measured in blood or in saliva [6, 9, 10],<br />
so studies using cotinine in blood and in saliva can be<br />
compared. Participants had not smoked for o20 days and had<br />
not used NRT or smokeless tobacco for o48 h (about three<br />
times the half-life of cotinine in smokers) [10]. Thus, results are<br />
unlikely to be contaminated by other sources of nicotine. All<br />
participants but one were former smokers, suggesting that<br />
ENDS are used much like NRT, to assist quitting, with similar<br />
or even larger effects on nicotine exposure. In this light, it<br />
seems logical to apply the same evaluation requirements to<br />
ENDS as to NRT. Even though propylene glycol is authorised<br />
as an additive in foods and medications, the effects of<br />
repeatedly inhaling a vapour containing propylene glycol over<br />
long periods are unknown.<br />
We relied on a self-selected sample and on self-reports of use of<br />
ENDS, tobacco and NRT, with no objective verification. Thus,<br />
our results may have limited generalisability and should be<br />
interpreted with caution. Nevertheless, this study shows that<br />
large amounts of nicotine can be obtained from ENDS and this<br />
calls for confirmation in representative samples or with different<br />
methods. Finally, technology progresses rapidly, and our results<br />
may not apply to future ENDS models.<br />
We conclude that cotinine levels in ENDS users were similar to<br />
levels observed, in previous reports, in smokers and higher than<br />
levels usually observed in NRT users. This finding has important<br />
implications for ENDS use by smokers who want to quit, for<br />
future research, and for the regulation of these products.<br />
J-F. Etter* and C. Bullen #<br />
*Institute of Social and Preventive Medicine, Faculty of Medicine,<br />
University of Geneva, Geneva, Switzerland, and # Clinical Trials<br />
Research Unit, School of Population Health, University of<br />
Auckland, Auckland, New Zealand.<br />
Correspondence: J-F. Etter, Institute of Social and Preventive<br />
Medicine, University of Geneva, CMU, Case Postale, CH-1211<br />
Geneva 4, Switzerland. E-mail: Jean-Francois.Etter@unige.ch<br />
Support Statement: No external funding was received for this<br />
study.<br />
Statement of Interest: Statements of interest for both authors<br />
of this manuscript can be found at www.erj.ersjournals.com/<br />
site/misc/statements.xhtml<br />
Acknowledgements: V. Baujard (HON Foundation, Geneva,<br />
Switzerland; www.hon.ch) developed the software for data collection.<br />
REFERENCES<br />
1 Etter J-F. Electronic cigarettes: a survey of users. BMC Public Health<br />
2010; 10: 231.<br />
2 Etter J-F, Bullen C. Electronic cigarettes: users profile, utilization,<br />
satisfaction and perceived efficacy. Addiction 2011; [Epub ahead of<br />
print DOI: 10.1111/j.1360-0443.2011.03505.x].<br />
3 Vansickel AR, Cobb CO, Weaver MF, et al. A clinical laboratory<br />
model for evaluating the acute effects of electronic ‘‘cigarettes’’:<br />
nicotine delivery profile and cardiovascular and subjective effects.<br />
Cancer Epidemiol Biomarkers Prev 2010; 19: 1945–1953.<br />
4 Bullen C, McRobbie H, Thornley S, et al. Effect of an electronic<br />
nicotine delivery device (e cigarette) on desire to smoke and<br />
withdrawal, user preferences and nicotine delivery: randomised<br />
cross-over trial. Tobacco Control 2010; 19: 98–103.<br />
5 Benowitz NL, Jacob P 3rd, Savanapridi C. Determinants of<br />
nicotine intake while chewing nicotine polacrilex gum. Clin<br />
Pharmacol Ther 1987; 41: 467–473.<br />
6 Wall MA, Johnson J, Jacob P, et al. Cotinine in the serum, saliva,<br />
and urine of nonsmokers, passive smokers, and active smokers.<br />
Am J Public Health 1988; 78: 699–701.<br />
7 Benowitz NL, Zevin S, Jacob P 3rd. Sources of variability in<br />
nicotine and cotinine levels with use of nicotine nasal spray,<br />
transdermal nicotine, and cigarette smoking. Br J Clin Pharmacol<br />
1997; 43: 259–267.<br />
8 Gourlay SG, Benowitz NL, Forbes A, et al. Determinants of plasma<br />
concentrations of nicotine and cotinine during cigarette smoking<br />
and transdermal nicotine treatment. Eur J Clin Pharmacol 1997; 51:<br />
407–414.<br />
9 Jarvis MJ, Tunstall-Pedoe H, Feyerabend C, et al. Comparison of<br />
tests used to distinguish smokers from nonsmokers. Am J Public<br />
Health 1987; 77: 1435–1438.<br />
10 Machacek DA, Jiang NS. Quantification of cotinine in plasma and<br />
saliva by liquid chromatography. Clin Chem 1986; 32: 979–982.<br />
DOI: 10.1183/09031936.00066011<br />
1220 VOLUME 38 NUMBER 5 EUROPEAN RESPIRATORY JOURNAL
Nachschlagewerk zum Thema E-Zigaretten<br />
3 ANALYSIS OF ELECTRONIC CIGARETTE
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ANALYSIS OF ELECTRONIC CIGARETTE<br />
CARTRIDGES, REFILL SOLUTIONS, AND<br />
SMOKE FOR NICOTINE AND NICOTINE<br />
RELATED IMPURITIES<br />
Michael L. Trehy a , Wei Ye a , Michael E. Hadwiger a , Terry W.<br />
Moore a , James F. Allgire a , Jeffrey T. Woodruff a , Shafiq S. Ahadi a<br />
, John C. Black a & Benjamin J. Westenberger a<br />
a<br />
Food and Drug Administration, Division of Pharmaceutical Analysis,<br />
Saint Louis, Missouri, USA<br />
Version of record first published: 25 Aug 2011.<br />
To cite this article: Michael L. Trehy , Wei Ye , Michael E. Hadwiger , Terry W. Moore , James F.<br />
Allgire , Jeffrey T. Woodruff , Shafiq S. Ahadi , John C. Black & Benjamin J. Westenberger (2011):<br />
ANALYSIS OF ELECTRONIC CIGARETTE CARTRIDGES, REFILL SOLUTIONS, AND SMOKE FOR NICOTINE AND<br />
NICOTINE RELATED IMPURITIES, Journal of Liquid Chromatography & Related Technologies, 34:14,<br />
1442-1458<br />
To link to this article: http://dx.doi.org/10.1080/10826076.2011.572213<br />
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Journal of Liquid Chromatography & Related Technologies, 34:1442–1458, 2011<br />
ISSN: 1082-6076 print/1520-572X online<br />
DOI: 10.1080/10826076.2011.572213<br />
ANALYSIS OF ELECTRONIC CIGARETTE CARTRIDGES, REFILL<br />
SOLUTIONS, AND SMOKE FOR NICOTINE AND NICOTINE<br />
RELATED IMPURITIES<br />
Michael L. Trehy, Wei Ye, Michael E. Hadwiger, Terry W. Moore,<br />
James F. Allgire, Jeffrey T. Woodruff, Shafiq S. Ahadi, John C. Black, and<br />
Benjamin J. Westenberger<br />
Food and Drug Administration, Division of Pharmaceutical Analysis, Saint Louis,<br />
Missouri, USA<br />
& The objective of this study was to determine nicotine and the nicotine related impurities, that is,<br />
cotinine, myosmine, anatabine, anabasine, and b-nicotyrine, in electronic cigarette cartridges, the<br />
liquid used to fill the cartridges, and from smoke generated using the electronic cigarette devices. An<br />
HPLC method was validated for the determination. Samples of nicotine containing products were<br />
purchased via the internet from NJOY, Smoking Everywhere, CIXI, and Johnson Creek. Electronic<br />
cigarette devices were purchased from NJOY, Smoking Everywhere, and CIXI. The results from the<br />
testing found that (1) the nicotine content labeling was not accurate with some manufacturers, (2)<br />
nicotine is present in the ‘‘smoke’’ from electronic cigarettes, and (3) nicotine related impurities<br />
contents in cartridges and refills were found to vary by electronic cigarette manufacturer.<br />
Keywords anatabine, cigarette, cotinine, e-cigarette, nicotine, smokeless<br />
INTRODUCTION<br />
‘‘Electronic cigarettes’’ are a recent entry into the market place. [1] The<br />
marketing of electronic cigarettes as a healthier alternative to smoking<br />
traditional cigarettes has raised some concerns. [2–6] In addition to the<br />
claim to deliver nicotine, the electronic cigarette manufacturers also<br />
claim electronic cigarettes are able to deliver other products including<br />
pharmaceuticals. [7–9] Electronic cigarettes have been reported to have different<br />
smoking characteristics from conventional cigarettes [10] and to have<br />
The findings and conclusions in this article have not been formally disseminated by the Food and<br />
Drug Administration and should not be construed to represent any Agency determination or policy.<br />
This article is not subject to US copyright laws.<br />
Address correspondence to Michael L. Trehy, Food and Drug Administration, Division of Pharmaceutical<br />
Analysis, 1114 Market St, Saint Louis, MO 63101, USA. E-mail: Michael.Trehy@fda.hhs.gov
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ineffective nicotine delivery. [11] Samples of nicotine containing products<br />
were purchased via the internet from NJOY, Smoking Everywhere, CIXI,<br />
and Johnson Creek. Electronic cigarette devices were purchased from<br />
NJOY, Smoking Everywhere, and CIXI. As part of an assessment of electronic<br />
cigarettes, the nicotine and nicotine related impurities, that is, cotinine,<br />
myosmine, anatabine, anabasine, and b-nicotyrine, were determined<br />
in selected products and in the ‘‘smoke’’ that would be inhaled by a consumer.<br />
Sample extracts of the products were analyzed using a validated<br />
gradient HPLC method described in this paper. The ‘‘smoke’’ of the cigarettes<br />
was analyzed following a ‘‘puff’’ procedure developed to simulate the<br />
use of the electronic cigarettes. The results obtained when testing the<br />
‘‘smoke’’ from electronic cigarettes was compared with results obtained<br />
using the same methodology with a popular brand of cigarette.<br />
Gas chromatographic, [12] capillary electrophoresis, [13] and liquid chromatographic<br />
[14] methods have been used for the determination of nicotine.<br />
The United States Pharmacopeia (USP): Nicotine Transdermal<br />
System assay method was modified and initially used for the determination<br />
of nicotine and nicotine related impurities. [14] However, due to poor retention<br />
of cotinine and poor resolution between nicotine and anabasine by the<br />
USP method, an improved HPLC gradient method was developed. In this<br />
paper, we present the improved HPLC conditions and results obtained<br />
analyzing several brands of electronic cigarettes.<br />
EXPERIMENTAL<br />
Chemicals<br />
Analysis of Electronic Cigarette’s Cartridges 1443<br />
Nicotine bitartrate dihydrate lot G1C070 was purchased from USP and<br />
found to contain 7.59% water by Karl Fischer titration. Nicotine content was<br />
calculated based on the chemical formula and corrected for water content.<br />
Cotinine catalog lot #2-XAL-53-1, myosmine lot #1-JLI-26-1, anabasine lot<br />
#2-BHW-20-1, b-nicotyrine lot #1-WHH-126-2, and anatabine tartrate (2:3)<br />
lot #9-BHW-79-2 were purchased from Toronto Research Chemicals, Inc.<br />
All were listed at 98% purity. Anatabine content was calculated based on the<br />
chemical formula and corrected for purity. OmniSolv acetonitrile high purity<br />
solvent and ammonium hydroxide from EM Science were purchased from<br />
Fisher Scientific. Ammonium formate was purchased from Sigma-Aldrich.<br />
Figure 1 provides the structures for the analytes of interest in this study.<br />
Electronic Cigarette Devices and Cartridges<br />
Samples of electronic cigarette devices and cartridges were purchased<br />
via the internet. Numerous suppliers of these devices exist and can be
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1444 M. L. Trehy et al.<br />
FIGURE 1 Structure for targeted analytes in this study are provided below.<br />
found in many booths in malls in the United States. This study represents a<br />
random sampling of four of these suppliers of cartridges, refills, and<br />
electronic cigarette devices.<br />
Equipment<br />
Two LC systems were used for analysis of samples. A Shimadzu HPLC<br />
with SPD-M10Avp diode array detector, DGU-14A Degasser, LC-10ADvp<br />
Pump, CTO-10ASvp Column Oven, SIL-10ADvp Auto injector, FCV-10ALvp<br />
Flow Controller, and SCL-10Avp System Controller was used for method<br />
development and for gradient analysis. The data were collected and processed<br />
employing Shimadzu CLASS-VP software version 5.032.
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An Agilent-1100-1 HPLC system with a variable wavelength detector,<br />
degasser, quaternary pump, column thermostat, and auto sampler was used<br />
for isocratic analysis.<br />
Chromatographic Conditions<br />
Analysis of Electronic Cigarette’s Cartridges 1445<br />
A Phenomenex Gemini-NX 5 m C18 110A 15 cm 4.6 mm column was<br />
used with the column temperature at 35 C and a flow rate of 1.0 ml=min.<br />
The injection volume was 10 mL, and quantification was carried out at<br />
260 nm. UV spectra were collected over the wavelength range 200 nm to<br />
350 nm. Eluent A was prepared to contain 10% acetonitrile in 20 mM<br />
ammonium formate adjusted to pH 8.7 by addition of approximately<br />
1 mL of concentrated aqueous ammonia per 2 liters of eluent A. Eluent<br />
B consisted of 100% acetonitrile. The gradient program was a series of<br />
linear gradients from initial conditions of 100% Ato80% A and 20% B<br />
at 10 min, then to 10% A and 90% B at 20 min then to 100% A at 21 min<br />
with a total run time of 30 min.<br />
The Agilent-1100-1 HPLC system was used with a Supelco LC-18-DB<br />
25 cm 4.6 mm 5-micron column. The injection volume was 10 mL and<br />
quantification was carried out at 260 nm. Flow rate was set to 1.2 mL=min<br />
with a run time of 15 min using isocratic elution. The mobile phase was<br />
23% acetonitrile with 0.1% triethylamine in water. The pH was adjusted<br />
to 9.1 with phosphoric acid.<br />
Preparation of Standard Solutions<br />
Stock solutions of cotinine, anabasine, anatabine, myosmine, nicotine,<br />
and b-nicotyrine were prepared in 50% methanol in water. Through serial<br />
dilutions of the stock standard with 10% acetonitrile in water, working standards<br />
were prepared from approximately 0.001 mg=mL to approximately<br />
0.05 mg=mL. These standards were then analyzed by the HPLC procedure<br />
to determine the limit of detection (LOD) and limit of quantification<br />
(LOQ) following ICH guidelines. [15]<br />
Preparation of Cartridge Samples and Refill Solutions for<br />
Content Analysis<br />
NJOY and Smoking Everywhere cartridges contained a plug at one end<br />
of the cartridge. The plug was intended to be removed when the electronic<br />
cigarette device containing a heating element was inserted into the cartridge.<br />
Removal of the plug allowed access to the cartridge’s contents of<br />
a propylene glycol solution of nicotine adhering to a loose fibrous pad.
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1446 M. L. Trehy et al.<br />
The pad was easily removed with tweezers, unwound, and transferred to an<br />
Erlenmeyer flask along with the plug and cartridge itself. Fifty mL of methanol<br />
was added to the flask, and the flask was stoppered.<br />
The CIXI cartridge contained a plug with an opening that allowed air<br />
to be drawn through the cartridge and was not intended for removal.<br />
In this style of cartridge, there was a heating element embedded in the<br />
fibrous pad. Removal of the plug allowed access to the cartridge’s propylene<br />
glycol solution of nicotine adhering to the tightly wound fibrous<br />
pad. The pad could only be removed by breaking the wires running to<br />
the heating element. It could then be removed with tweezers, unwound,<br />
and transferred to an Erlenmeyer flask along with the plug and cartridge<br />
itself. Fifty mL of methanol was added to the flask and the flask was<br />
stoppered.<br />
The flasks were placed on a platform shaker and shaken for 90 min.<br />
The extract was transferred to 50 mL Erlenmeyer flasks for analysis.<br />
Extracts were clear and did not require filtration prior to analysis.<br />
Refill solutions from Johnson Creek were in individual vials. Analysis of<br />
refill solutions was made after dilution with mobile phase or 10% acetonitrile<br />
and ran by the HPLC procedure.<br />
Puff Analysis<br />
Fifty mL of extraction solution (10% acetonitrile in water) and a<br />
magnetic stirrer was added to a tall-form gas washing fritted cylinder bottle<br />
similar to Fisher catalog #03-040A with 150 mL cylinder and coarse frit.<br />
The trap was placed on top of a magnetic stirrer and mixed slowly<br />
throughout the trapping process. The electronic cigarette or standard cigarette<br />
was attached to the sparger via tubing in such a manner as to<br />
minimize the amount of tubing exposed to the air passing through the<br />
electronic cigarette to the sparger. The outlet from the gas washing bottle<br />
was connected via tubing to a Dräger manual air pump with a capacity of<br />
100 mL. At one minute intervals, a puff of 100 mL of air was drawn through<br />
the electronic cigarette through the sintered glass frit into the gas washing<br />
bottle containing the extraction solution. A total of 30 puffs were collected<br />
in this manner. The electronic cigarette was observed to stay lit for approximately<br />
2 sec after the 100 mL puff of air was initially actuated, and the air<br />
flow into the washing bottle stopped approximately 4 sec after the 100 mL<br />
puff of air was initiated. The electronic cigarette device contains an air flow<br />
sensor which is actuated by the puff of air. When actuated, the electronic<br />
cigarette LED light at the tip of the cigarette lights and the heating element<br />
is heated. The electronic cigarette was observed to light each time the air<br />
was drawn through the tube. An experiment set up to trap the ‘‘smoke’’
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Analysis of Electronic Cigarette’s Cartridges 1447<br />
from an electronic cigarette is shown in Figure 2a and is configured with<br />
two traps to confirm that tobacco related impurities were being confined<br />
to the first trap. Normal operation involved using only a single trap. An<br />
experiment to trap smoke from a traditional cigarette is shown for comparison<br />
in Figure 2b.<br />
FIGURE 2 (a) Photograph of experimental set up for electronic cigarette testing. (b) Photograph of<br />
experimental set up for traditional cigarette testing. (Color figure available online.)
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1448 M. L. Trehy et al.<br />
Method Validation<br />
Precision of the HPLC determinative step was evaluated by seven replicate<br />
injections of a standard and calculation of the average, standard deviation,<br />
and percent relative standard deviation for nicotine and each of the<br />
five nicotine related impurities selected for analysis. Limit of detection<br />
(LOD) and limit of quantitation (LOQ) were determined following ICH<br />
guidelines based on the standard deviation of the response and the<br />
slope. [15] Linearity was determined using serial dilutions of a mixed standard<br />
containing all six components. Percent recovery was determined by<br />
spiking diluted sample with the analytes and calculating the percent recovery<br />
after subtracting the areas due to the sample matrix.<br />
Sample Collection<br />
Samples of electronic cigarettes and devices were purchased over an<br />
approximately one year period via internet purchases. The initial survey<br />
obtained electronic cigarette devices, refill solutions, and cartridges from<br />
NJOY and Smoking Everywhere. The devices, refill solutions, and cartridges<br />
were similar in design and properties. A third supplier, Johnson Creek was<br />
sampled for cartridges and refill solutions. The Johnson Creek cartridges<br />
were similar in design to the first two sets of samples. The final set of samples<br />
including cartridges, refill solutions, and devices was collected from<br />
the CIXI and the design of the cartridges and electronic cigarette was<br />
different.<br />
RESULTS AND DISCUSSION<br />
HPLC Method Development and Optimization<br />
The objective of the method was to measure nicotine, cotinine, myosmine,<br />
anatabine, anabasine, and b-nicotyrine in electronic cigarette cartridges<br />
and from ‘‘smoke’’ generated using the electronic cigarette devices.<br />
Information from the internet provided an estimate for the concentration<br />
of nicotine likely to be present. No information was available regarding the<br />
likely concentrations of nicotine related impurities associated with the<br />
nicotine or in the electronic cigarette ‘‘smoke.’’<br />
Initial analysis followed a procedure similar to the USP method [14]<br />
employing a Supelco NO. 5-875 LC-18-DB 25 cm 4.6 mm 5-micron column<br />
with isocratic elution using 23% acetonitrile containing 0.1% triethylamine,<br />
a flow rate of 1.2 mL per minute, and a column temperature of<br />
35 C. Using these conditions, cotinine was poorly retained, and anabasine
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Analysis of Electronic Cigarette’s Cartridges 1449<br />
was not completely resolved from nicotine due to the broad peak observed<br />
for nicotine at the sample concentrations used for analysis.<br />
An alternative method was developed using gradient elution and a<br />
Phenomenex 1 Gemini-NX 5 mm C18 110A 15 cm 4.6 mm column to<br />
improve resolution. The LC conditions are listed in the Chromatographic<br />
Conditions section. Under these conditions all the components are resolved<br />
as shown in Figure 3 with a resolution greater than 4.0 and with peak asymmetry<br />
ranging from 1.12 to 1.32 for all the components. The pH of the eluent<br />
greatly impacted resolution. When the pH of eluent A is 8.7 all<br />
components listed were resolved while at a pH of 8.9 all the peaks were<br />
not resolved. This method was used for analysis of electronic cigarette cartridges<br />
and for the trapping solution obtained from the electronic<br />
cigarette smoke for CIXI and for the analysis of the smoke from a popular<br />
cigarette brand.<br />
The method was linear over the range of standards prepared and had a<br />
percent relative standard deviation of less than 1% for seven replicate injections<br />
of the highest standard tested for each of the analytes. Linearity as<br />
measured by the correlation coefficient was 1.000 for all the analytes tested.<br />
A comparison of the LOD and LOQ values using isocratic elution and the<br />
Supelco LC-18-DB column compared to the results obtained using gradient<br />
elution and the Phenomenex Gemini-NX 5 m C18 110A 15 cm 4.6 mm column<br />
are shown in Table 1. The limit of detection (LOD) and limit of quantitation<br />
(LOQ) were determined by calculating the standard error for the<br />
FIGURE 3 Chromatogram for nicotine and nicotine related impurities. Retention times; cotinine<br />
(5.94 min), anabasine (9.515 min), anatabine (10.155 min), myosmine (11.307 min), nicotine<br />
(13.557 min), and b-nicotyrine (17.717 min).
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1450 M. L. Trehy et al.<br />
TABLE 1 Comparison of LOD and LOQ Values for Isocratic Elution with a Supelco LC-18-DB 250 mm<br />
Column versus a Phenomenex Gemini-NX 5m C18 110A 15 cm 4.6 mm Column<br />
LOD, LOQ, Linearity, and %RSD for Isocratic HPLC Method w Supelco<br />
Range<br />
mg=mL Std<br />
LOD – LOQ mg=mL<br />
Tobacco Soln<br />
Recovery (%)<br />
at Max Range<br />
intercept and dividing by the slope of the line of best fit and then multiplying<br />
by 3.3 for the LOD and by 10 for the LOQ. [15] The percent recovery was<br />
determined by spiking a diluted sample at the high end of the concentration<br />
range used for the linearity determination.<br />
Design Differences in Electronic Cigarette Devices<br />
RSD (%) 7 inj<br />
at Max Range<br />
Cotinine 0.02–24.2 0.57–1.70 81.8 0.62<br />
Anabasine 0.02–22.8 6.10–18.50 67.8 3.37<br />
Anatabine 0.03–34.6 1.10–3.40 93.4 2.97<br />
Myosmine 0.01–10.3 1.10–3.30 95.9 1.23<br />
Nicotine 0.06–72.4 34.00–104.00 0.77<br />
b-Nicotyrine 0.01–9.3 0.30–0.96 100.8 1.70<br />
LOD, LOQ, Linearity, and RSD (%) for Gradient HPLC Method Phenomenex<br />
Range<br />
mg=ml Std<br />
LOD – LOQ mg=mL<br />
Tobacco Soln<br />
Recovery (%)<br />
at Max Range<br />
RSD (%) 7 inj<br />
at Max Range<br />
Cotinine 1.4–87.6 0.2–0.70 99.4 0.3<br />
Anabasine 1.2–76.5 0.4–1.30 100.2 0.3<br />
Anatabine 0.3–15.9 0.1–0.30 100.1 0.5<br />
Myosmine 0.6–35.4 0.1–0.30 99.4 0.3<br />
Nicotine 0.2–15.3 0.1–0.25 99.6 0.4<br />
b-Nicotyrine 0.6–36.3 0.1–0.40 100.4 0.3<br />
Samples of electronic cigarette devices and cartridges were obtained<br />
from NJOY, Smoking Everywhere, and CIXI. NJOY and Smoking Everywhere<br />
were indistinguishable in design. NJOY and Smoking Everywhere<br />
had used a rubber plug possibly made of silicone to seal the end of the cartridge<br />
prior to connecting to the electronic cigarette device. The plug<br />
absorbed a portion of the nicotine which likely was partially responsible<br />
for lower nicotine values than indicated on the internet. CIXI had a different<br />
cartridge design and electronic cigarette device from the other two<br />
manufacturers.<br />
All three electronic cigarette devices contain a rechargeable battery, a<br />
light emitting diode (LED), and an air flow sensor that is activated when<br />
the flow of air through the device exceeds a predetermined level. On activation,<br />
the LED light is turned on along with the heating element as shown<br />
in Figure 2a. The consumer can visually observe whether sufficient air is
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Analysis of Electronic Cigarette’s Cartridges 1451<br />
being drawn through the device to activate the heater. In the case of manufacturers<br />
NJOY and Smoking Everywhere, the heating element was part of<br />
the cigarette device and when the cartridge plug was removed and the cartridge<br />
attached to the electronic cigarette device, the heating element was<br />
placed in contact with the nicotine containing solution on a fiber mat. CIXI<br />
had placed the heating element inside the cartridge and electrical contact<br />
was made when the cartridge was connected to the device.<br />
The air flow necessary to actuate the flow sensor was determined by<br />
connecting the device to a vacuum and measuring the air flow with a<br />
Gilmont air flow meter. The minimum air flow to actuate the heating<br />
element and LED was determined to be 52 mL per second. In the puff<br />
analysis testing used in this study, a 100 mL puff was drawn through the<br />
device at 1 min intervals. The LED light was observed to stay lit for approximately<br />
2 sec and air flow had completely stopped after 4 sec. Typical<br />
conditions for testing cigarettes under FTC [12,16,17] conditions is 1 min puff<br />
interval, 2 sec puff duration, and 35 mL total puff volume. The flow rate for<br />
these conditions would not actuate the electronic cigarette device.<br />
In order to evaluate the nicotine delivery under greatly varying conditions,<br />
the amount of nicotine delivered was determined with no pause<br />
between puffs with and without battery attached to simulate performance<br />
with a dead battery and compared to the standard procedure used in this<br />
study which employed a 30 sec pause between puffs. The electronic cigarette’s<br />
nicotine delivery was greatly enhanced by reducing the pause<br />
between puffs and removing the battery greatly reduced nicotine delivery<br />
Figure 4. Nicotine delivery appeared to be greatly impacted by the temperature<br />
of the nicotine solution so that repeated heating in a short time<br />
FIGURE 4 Nicotine delivery is greatly impacted by time between puffs.
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1452 M. L. Trehy et al.<br />
interval enhanced nicotine release. Since most people who smoke take a<br />
pause of variable length, the actual amount of nicotine delivered is likely<br />
to be highly variable.<br />
Nicotine Content of Electronic Cigarette Cartridges<br />
Nicotine content labeling issues existed with all of the manufacturers<br />
tested. Results are summarized in Table 2. Methanol extracts of the cartridges<br />
were diluted with Milli-Q water and analyzed by HPLC following<br />
the modified USP procedure [14] and compared to the results employing<br />
the gradient procedure. NJOY and Smoking Everywhere have results which<br />
overlap dosage levels so that little differentiation exists. CIXI is completely<br />
inconsistent. Some cartridges labeled as containing nicotine, did not contain<br />
nicotine and some cartridges labeled as not containing nicotine, did<br />
contain nicotine. Further, when a particular flavor type from CIXI labeled<br />
as containing nicotine was analyzed, only one of the seven cartridges analyzed<br />
was found to contain nicotine.<br />
Nicotine Related Impurities in Cartridge Extracts<br />
The nicotine content and nicotine related impurities were determined<br />
in the cartridge extracts using the gradient elution method. Results are<br />
TABLE 2 Nicotine Label Content versus Nicotine Content Found for Cartridges from Three Different<br />
Manufacturers<br />
Smoking Everywhere NJOY CIXI<br />
Label mg<br />
Nicotine<br />
per Cartridge<br />
Actual mg<br />
Nicotine<br />
per Cartridge<br />
Label mg<br />
Nicotine<br />
per Cartridge<br />
Actual mg<br />
Nicotine<br />
per Cartridge<br />
Label mg<br />
Nicotine<br />
per Cartridge<br />
Actual mg<br />
Nicotine<br />
per Cartridge<br />
0 0.1 6 5.2 0 0.07<br />
0 0.0 12 5.3 0 12.90<br />
0 0.0 12 4.3 0 21.80<br />
0 0.1 12 4.8 16 0.09<br />
0 0.0 18 6.8 16 21.00<br />
6 1.0 16 13.00<br />
6 1.6 24 0.09<br />
6 2.7 24 13.20<br />
6 1.8 24 20.60<br />
11 5.2 24 15.10<br />
11 2.7<br />
11 4.4<br />
16 6.0<br />
16 4.2<br />
16 5.5
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TABLE 3 Results from CIXI for Nicotine and Nicotine Related Impurities in Cartridges Expressed as<br />
mg=Cartridge<br />
Nicotine, Flavor Cotinine Myosmine Anatabine Anabasine Nicotine b-Nicotyrine<br />
None, regular ND
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1454 M. L. Trehy et al.<br />
Nicotine Content of Refill Solutions<br />
Table 4 summarizes the results for nicotine content found on analyzing<br />
two manufacturers of electronic cigarette refill solutions. Johnson Creek<br />
consistently matched the label specification with the range 100.2% to<br />
110.8% of label value. However, CIXI did not consistently match the label<br />
claim. The nicotine content followed the flavor labeling so that all ‘‘regular<br />
flavor’’ refill solutions did not contain nicotine even though they were<br />
labeled to contain variable concentrations of nicotine. Of greatest concern<br />
was the high nicotine content in refill solutions labeled to contain no<br />
nicotine.<br />
Nicotine and Nicotine Related Impurities in Puff Trapping<br />
Solutions<br />
Electronic cigarettes were found to deliver nicotine at a consistent rate<br />
for a given cartridge and electronic cigarette device as shown in Figure 6<br />
when a constant puff pause interval of 1 min was used. However, cartridge<br />
contents vary significantly from one cartridge to another so that actual performance<br />
from one electronic cigarette cartridge combination to another is<br />
highly variable. This is especially true from one manufacturer to another.<br />
The variability within a single manufacturer and cartridge is similar to that<br />
observed when a popular cigarette was tested under the same conditions as<br />
shown in Table 5.<br />
Although, nicotine related impurities were not detected in the puffs<br />
above the LOQ for the electronic cigarettes, this is attributable to the lower<br />
nicotine delivery observed and not the absence of nicotine impurities in the<br />
TABLE 4 Nicotine Results for e-Cigarette Refills from Two Manufacturers<br />
CIXI Label mg<br />
Nicotine=mL<br />
(flavor)<br />
mg<br />
Nicotine=mL<br />
% of<br />
Label<br />
Johnson Creek Label<br />
mg Nicotine=mL<br />
(flavor)<br />
mg<br />
Nicotine=mL<br />
% of<br />
Label<br />
0 (Regular Flavor) 0 – 24 (Original Smoke RPG) 25.6 106.5<br />
24 (Regular Flavor) 0 0 24 (Tennessee Cured RPG) 25.4 106.0<br />
16 (Regular Flavor) 0 0 24 (Tennessee Cured PG) 25.4 105.9<br />
24 (Cialis) 13 54 18 (Tennessee Cured PG) 19.9 110.8<br />
0 (Cialis) 12 – 0 (Tennessee Cured PG) 0.0 –<br />
16 (Cialis) 13 81 24 (Simply Strawberry PG) 24.8 103.2<br />
24 (Marlboro Flavor) 14 58 18 (Simply Strawberry PG) 18.0 100.2<br />
0 (Rimonabant) 21 – 24 (Espresso PG) 24.9 103.6<br />
24 (Rimonabant) 20 83 18 (Espresso PG) 18.8 104.4<br />
16 (Rimonabant) 20 125 0 (Espresso PG) 0.0 –<br />
24 (Original PG) 24.6 102.5<br />
18 (Original PG) 18.9 105.2
Downloaded by [77.21.82.66] at 09:13 04 March 2013<br />
Analysis of Electronic Cigarette’s Cartridges 1455<br />
FIGURE 6 Nicotine release from an electronic cigarette versus the number of 100 mL puffs. (Color<br />
figure available online.)<br />
smoke. Note that at the nicotine levels observed, the corresponding amount<br />
of anatabine that would be present is below the method LOD. In the trapping<br />
solution for smoke from a traditional cigarette, anabasine was the<br />
nicotine related impurity present at the highest relative concentration at<br />
12% of the nicotine content. Results for nicotine related impurities are<br />
shown in Table 6. In Figure 7, chromatograms from the trapping solutions<br />
after thirty 100 mL puffs from (a) a popular traditional cigarette is compared<br />
to (b) an electronic cigarette using a cartridge labeled to contain<br />
24 mg of nicotine=cartridge. The impurity level as a percentage of the area<br />
for nicotine appears to be lower in the trapping solution from the electronic<br />
cigarette than in the trapping solution from a traditional cigarette.<br />
TABLE 5 Simulated Smoking Evaluation Results for Nicotine Delivery<br />
mg Nicotine=100 mL<br />
Puff Measured mg Nicotine=Cartridge Measured<br />
E-cigarette label value Smoking Everywhere<br />
11 mg=cartridge 10.6 4.77<br />
16 mg=cartridge 26.8, 34.9, 43.2 6.76<br />
E-cigarette NJOY<br />
6mg=cartridge 9.9 1.57<br />
12 mg=cartridge 15.7 5.15<br />
18 mg=cartridge 31.5 5.98<br />
E-cigarette CIXI<br />
16 mg=cartridge 14.4, 4.4, 6.6 21.0<br />
24 mg=cartridge 0 0<br />
24 mg=cartridge 2.1, 2.4, 0.6 13.2<br />
Traditional Cigarette<br />
Marlboro 193, 154, 152
Downloaded by [77.21.82.66] at 09:13 04 March 2013<br />
1456 M. L. Trehy et al.<br />
TABLE 6 Simulated Smoking Evaluation for Nicotine Related Impurities<br />
Nicotine, Flavor Cotinine Myosmine Anatabine Anabasine Nicotine b-Nicotyrine<br />
E-cigarette CIXI<br />
High ND ND ND ND 254 ND<br />
E-High ND ND
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Rimonabant and Amino-Tadalafil<br />
As previously reported, [9] CIXI markets several products containing<br />
additional active ingredients including rimonabant and amino-tadalafil.<br />
The Cialis E-Cartridges and E-Liquids were mislabeled as they contained<br />
amino-tadalafil not tadalafil, the reference listed drug in Cialis. The<br />
E-Cartridges contained 12 mg amino-tadalafil=cartridge; there was no label<br />
declaration. The E-Liquid contained 17 mg=mL in one sample and<br />
5mg=mL in another; there were no label declarations. The manufacturer’s<br />
website indicated there was 16 mg of tadalafil in the cartridge and<br />
20 mg=mL tadalafil in the E-Liquid.<br />
The Rimonabant E-Cartridges contained 3 mg rimonabant per<br />
cartridge, and two E-Liquids samples contained 3 mg=mL and 4 mg=mL<br />
rimonabant; there were no label declarations. The manufacturer’s website<br />
indicated there was 20 mg=mL rimonabant in the E-Liquid and 16 mg=<br />
cartridge in the E-Cartridges.<br />
Analysis of the puff trapping solutions from electronic cigarettes using<br />
cartridges containing rimonabant and amino-tadalafil did not detect either<br />
rimonabant or amino-tadalafil in the trapping solution. The results suggest<br />
that under our testing conditions transfer of rimonabant and aminotadalafil<br />
to the vapor phase is low.<br />
CONCLUSIONS<br />
The gradient elution method was developed to allow for separation of<br />
the nicotine related impurities and for their determination in cartridge<br />
extracts of the electronic cigarettes. Nicotine was shown to be delivered<br />
using electronic cigarette devices although the amount of nicotine delivered<br />
will be greatly impacted by the ‘‘smoking’’ habits of the consumer.<br />
Significant labeling issues were found to exist with products in the market<br />
place with respect to product labeling accuracy. Some products were found<br />
to contain high concentrations of nicotine when labeled not to contain<br />
nicotine.<br />
REFERENCES<br />
Analysis of Electronic Cigarette’s Cartridges 1457<br />
1. Lik, H. PCT Int. Appl. (2004), WO 2004080216 A1 20040923.<br />
2. Pauly, J.; Quiang, L.; Barry, M. B. Tobacco-Free Electronic Cigarettes and Cigars Deliver Nicotine<br />
and Generate Concern. Tob. Control 2007, 16, 357.<br />
3. Kuehn, B. M. FDA: Electronic Cigarettes May Be Risky. JAMA 2009, 302, 937.<br />
4. Wollscheid, K. A.; Kremzner, M. E. Electronic Cigarettes: Safety Concerns and Regulatory Issues.<br />
Am. J. Health-Syst. Pharm. 2009, 66, 1740–1742.<br />
5. Flouris, A. D.; Oikonomou, D. N. Electronic Cigarettes: Miracle or Menace? BMJ (Clinical Research<br />
ed.) 2010, 340, c311.
Downloaded by [77.21.82.66] at 09:13 04 March 2013<br />
1458 M. L. Trehy et al.<br />
6. Trtchounian, A.; Talbot, P. Electronic Nicotine Delivery Systems: Is There a Need for Regulation?<br />
Tob. Control. 2011, 20, 47–52.<br />
7. Jian, H. Electronic Cigarette Atomizing Solution Containing Tobacco Leaf Extract, Propanediol,<br />
Tobacco Essence and Nicotine. Faming Zhuanli Shenqing Gongkai Shuomingshu, CN 101461566 A<br />
20090624, 2009.<br />
8. Jian, H. Preparation of a Spray Solution Containing Chinese Medicinal Extracts for Electronic<br />
Cigarettes. Faming Zhuanli Shenqing Gongkai Shuomingshu, CN 101461565 A 20090624, 2009.<br />
9. Hadwiger, M. E.; Trehy, M. L.; Ye, W.; Moore, T.; Allgire, J.; Westenberger, B. J. Identification of<br />
Amino-Tadalafil and Rimonabant in Electronic Cigarette Products Using HPLC with Diode Array<br />
and Tandem Mass Spectrometric Detection. J. Chromatogr. A 2010, 1217, 7547–7555.<br />
10. Trtchounian, A.; Williams, M.; Talbot, P. Conventional and Electronic Cigarettes (E-Cigarettes)<br />
Have Different Smoking Properties. Nicotine Tob. Res. 2010, 12, 905–912.<br />
11. Eissenberg, T. Electronic Nicotine Delivery Devices: Ineffective Nicotine Delivery and Craving<br />
Suppression After Acute Administration. Tob. Control 2010, 19, 87–88.<br />
12. Watson, C. H.; Trommel, J. S.; Ashley, D. L. Solid-Phase Microextraction–Based Approach to<br />
Determine Free-Base Nicotine in Trapped Mainstream Cigarette Smoke. J. Agric. Food Chem. 2004,<br />
52, 7240–7245.<br />
13. Yang, S. S.; Smetena, I.; Goldsmith, A. I. Evaluation of Micellar Electrokinetic Capillary Chromatography<br />
for the Analysis of Selected Tobacco Alkaloids. J. Chromatog. A 1996, 746, 131–136.<br />
14. United States Pharmacopeia. USP32=NF27 Vol. 3, 2009; pp 3079–3081.<br />
15. ICH Q2B, Validation of Analytical Procedures: Methodology, 1996.<br />
16. Pankow, J. F.; Tavakoli, A. D.; Luo, W.; Isabelle, L. M. Percent Free-Base Nicotine in the Tobacco<br />
Smoke Particulate Matter of Selected Commercial and Reference Cigarettes. Chem. Res. Toxicol.<br />
2003, 16, 1014–1018.<br />
17. Rustemeier, K.; Piade, J. J. Determination of Nicotine in Mainstream and Sidestream Cigarette<br />
Smoke. In Analytical Determination of Nicotine and Related Compounds and Their Metabolites; Gorrod,<br />
J. W., Peyton, J. III, Eds.; Elsevier: Amsterdam, 1999, pp. 489–529.
Nachschlagewerk zum Thema E-Zigaretten<br />
4 Tests for the chronic toxicity of propylene glycol<br />
and triethylene glycol on monkeys and rats by<br />
vapor inhalation and oral administration.
http://jpet.aspetjournals.org/content/91/1/52.abstract 1/2<br />
HOME CURRENT ISSUE ARCHIVE FEEDBACK SUBSCRIPTIONS ALERTS HELP<br />
TESTS FOR THE CHRONIC TOXICITY OF<br />
PROPYLEXE GLYCOL AND TRIETHYLENE<br />
GLYCOL ON MONKEYS AND RATS BY VAPOR<br />
INHALATION AND ORAL ADMINISTRATION<br />
O. H. ROBERTSON, CLAYTON G. LOOSLI, THEODORE T. PUCK, HENRY WISE,<br />
HENRY M. LEMON and WILLIAM LESTER, JR.<br />
+ Author Affiliations<br />
Abstract<br />
With a view to determining the safety of employing the vapors of propylene glycol and<br />
triethylene glycol in atmospheres inhabited by human beings, monkeys and rats were<br />
exposed continuously to high concentrations of these vapors for periods of 12 to 18<br />
months. Equal numbers of control animals were maintained under physically similar<br />
conditions. Long term tests of the effects on ingesting triethylene glycol were also carried<br />
out. The doses administered represented 50 to 700 times the amount of glycol the animal<br />
could absorb by breathing air saturated with the glycol.<br />
Comparative observations on the growth rates, blood counts, urine examinations, kidney<br />
function tests, fertility and general condition of the test and control groups, exhibited no<br />
essential differences between them with the exception that the rats in the glycol<br />
atmospheres exhibited consistently higher weight gains. Some drying of the skin of the<br />
monkeys' faces occurred after several months continuous exposure to a heavy fog of<br />
triethylene glycol. However, when the vapor concentration was maintained just below<br />
saturation by means of the glycostat this effect did not occur.<br />
Examination at autopsy likewise failed to reveal any differences between the animals kept<br />
in glycolized air and those living in the ordinary room atmosphere. Extensive histological<br />
study of the lungs was made to ascertain whether the glycol had produced any<br />
generalized or local irritation. None was found. The kidneys, liver, spleen and bone marrow<br />
also were normal.<br />
The results of these experiments in conjunction with the absence of any observed ill<br />
effects in patients exposed to both triethylene glycol and propylene glycol vapors for<br />
months at a time, provide assurance that air containing these vapors in amounts up to the<br />
saturation point is completely harmless.<br />
Footnotes<br />
Received June 4, 1947.<br />
Articles citing this article<br />
Final Report on the Safety Assessment of Triethylene Glycol and PEG-4<br />
International Journal of Toxicology March 1, 2006 25:121-138<br />
Abstract Full Text Full Text (PDF)<br />
Ozone and Glycol Vapor Decontamination of Air in a Closed Room<br />
JDR September 1, 1974 53:1132-1137<br />
Abstract Full Text (PDF)<br />
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ISSN 1521-0103 (Online)
Nachschlagewerk zum Thema E-Zigaretten<br />
5 Electronic cigarettes (e-cigarettes) as potential<br />
tobacco harm reduction products: Results of an<br />
online survey of e-cigarette users.
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an<br />
online survey of e-cigarette users<br />
Karyn Heavner, PhD, MSPH (Corresponding author)<br />
University of Alberta, School of Public Health<br />
karynkh@aol.com<br />
James Dunworth, BA, PGCE<br />
E Cigarette Direct<br />
james.dunworth@ecigarettedirect.co.uk<br />
Paul Bergen, MSc, MLIS<br />
University of Alberta, School of Public Health<br />
pbergen1@gmail.com<br />
Catherine Nissen, BSc<br />
University of Alberta, School of Public Health<br />
cmnissen@gmail.com<br />
Carl V. Phillips, PhD, MPP<br />
University of Alberta, School of Public Health<br />
cvphilo@gmail.com<br />
1
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Abstract<br />
Electronic cigarettes (e-cigarettes), which surged in popularity in 2008, may be the most<br />
promising product for tobacco harm reduction yet. E-cigarettes deliver a nicotine vapor without<br />
the combustion products that are responsible for nearly all of smoking’s health effects. Other<br />
than anecdotal accounts, there is little information about who uses e-cigarettes, and whether<br />
people who switch from cigarettes to e-cigarettes experience changes in symptoms caused by<br />
smoking. This pilot online survey, conducted by a UK-based online e-cigarette merchant (E<br />
Cigarette Direct), investigated e-cigarette use for smoking cessation and changes in health status<br />
and smoking caused symptoms. A convenience sample (n=303) was enrolled by e-mail and<br />
links on various blogs and forums in May-June 2009. The data were analyzed by independent<br />
university researchers at the tobaccoharmreduction.org project.<br />
All respondents previously smoked and 91% had attempted to stop smoking before trying ecigarettes.<br />
Most respondents resided in the USA (72%) and 21% were in Europe. About half<br />
(55%) were 31-50, while 32% were >50 years old. Most (79%) of the respondents had been<br />
using e-cigarettes for
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Introduction<br />
Awareness and use of electronic cigarettes (e-cigarettes) has dramatically increased in the past<br />
two years. These devices, which are manufactured and sold by several different companies,<br />
deliver nicotine by vaporizing a gel composed of water, propylene glycol, flavorings, and<br />
nicotine [1]. E-cigarettes deliver nicotine without the products of combustion that are inhaled by<br />
smoking cigarettes. Therefore, the health risks are likely similar to those from smokeless<br />
tobacco, which has approximately 1% of the mortality risk of smoking [2]. There is likely some<br />
remaining risk due to the stimulant effects of nicotine. E-cigarettes are one category of noncombustion<br />
nicotine product (others being smokeless tobacco and pharmaceutical nicotine<br />
products) that are promising for tobacco harm reduction, the substitution of less harmful nicotine<br />
products for cigarettes [3,4].<br />
E-cigarettes are widely available in the United States and Europe and are also available online<br />
through many different distributors. E-cigarettes have been banned in some jurisdictions<br />
including Canada [5,6] and Victoria (Australia) [6] and are subject to the indoor “smoking” bans<br />
in others (e.g., [7]). Although there are legitimate concerns about quality control and product<br />
tampering, the importation/sale bans have been criticized by public health advocates because<br />
they do not merely address the products’ flaws, but eliminate a promising smoking cessation<br />
intervention, offering few realistic options for bringing the product back to market. There is a<br />
high likelihood that some people who switched from cigarettes to e-cigarettes but lose access to<br />
e-cigarettes will resume smoking.<br />
There are many testimonials and anecdotes on the internet about people switching from<br />
cigarettes to e-cigarettes but, to our knowledge, there have been no quantified data published.<br />
One online e-cigarette distributor based in the United Kingdom (E Cigarette Direct) conducted<br />
an online marketing survey of their e-cigarette users and made their data available to researchers<br />
at the University of Alberta School of Public Health for re-analysis. The objectives of this study<br />
were to describe e-cigarette users' patterns of cigarette and e-cigarette usage and smoking<br />
cessation attempts and to compare health status and smoking-attributable symptoms between<br />
people who completely switched from smoking to e-cigarettes, those who partially switched, and<br />
those who supplemented cigarette smoking with e-cigarette usage.<br />
Methods<br />
The study was initiated and conducted by E Cigarette Direct (ecigarettedirect.co.uk). A<br />
convenience sample was enrolled by sending an e-mail to their consumers and links to the survey<br />
were available on their website and on various blogs and online forums. Most of the survey<br />
respondents were directed to the survey from an e-cigarette forum. Participants completed an<br />
online survey in English on the SurveyMonkey website in May and June 2009. The survey was<br />
not anonymous as SurveyMonkey tracks respondents' IP addresses and E Cigarette Direct gave<br />
participants the option of providing their e-mail address to be entered in a raffle (as is common<br />
practice for marketing surveys). Duplicate IP and e-mail addresses were identified and then these<br />
variables were deleted (by JD) prior to sending the data to the University of Alberta research<br />
team (tobaccoharmreduction.org) for analysis. Secondary analysis of the anonymized version of<br />
the dataset was approved by the Health Research Ethics Board at the University of Alberta.<br />
3
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
The survey assessed respondents' use of cigarettes, e-cigarettes, smoking cessation (including use<br />
of pharmaceutical products and switching to e-cigarettes) and changes in smoking-caused<br />
symptoms since using e-cigarettes. The dataset included 304 observations, one of which was<br />
excluded from all analyses because only country of residence and comments were entered.<br />
There were two sets of two observations each which had the same IP address. There were no<br />
entries with the same e-mail address. In addition, there were 31 observations with no IP or email<br />
address.<br />
All analyses were conducted for the whole sample and for a subsample of the dataset that<br />
excluded potential duplicates. The subset excluded all observations without an IP or email<br />
address and the observation that was completed last in each of the two sets with the same IP<br />
address. The results section focuses on the analysis of the whole sample with differences<br />
between the whole sample and the subsample noted. The data were analyzed in SAS (version<br />
9.2, SAS Institute, Cary, North Carolina). Our analysis included frequencies of all variables. Our<br />
protocol specified conducting cross tabulations for switching behavior and health status and<br />
smoking symptoms. Tests of significance were not conducted as no specific hypothesis were<br />
tested and confidence limits are not presented because they tend to mislead most readers into<br />
thinking they represent the important source of error. Confidence intervals only convey<br />
information about random error, while the greatest potential sources of error in this and other<br />
surveys of self-reported health and behavior are non-random.<br />
Results<br />
The frequencies of all survey questions are listed in Table 1. Approximately half of the sample<br />
was between the ages of 31 and 50, one-third were more than 50 years old and none were under<br />
the age of 18. Nearly three-quarters resided in the US, followed by 17% from the UK. Most of<br />
the respondents had been using e-cigarettes for less than six months and all had smoked prior to<br />
using e-cigarettes. Most of the respondents had previously tried to stop smoking multiple times.<br />
The majority (86%) of respondents had tried pharmaceutical products to quit smoking, nearly<br />
two-thirds of whom indicated that these products did not help them to stop smoking. However,<br />
most of the sample was able to use e-cigarettes as a complete replacement for cigarettes.<br />
The majority of the respondents indicated that their general health, smoker’s cough, ability to<br />
exercise, sense of smell and sense of taste were better since starting to use e-cigarettes and none<br />
indicated that these were worse when responding to these five questions. However, one<br />
participant (whose data was excluded from the rest of the analysis because he/she only entered<br />
country of residence and comments) indicated in the comments that his/her health was generally<br />
worse since starting to use e-cigarettes but believed that this was due to a concurrent dramatic<br />
decrease in caffeine intake. There were only minor differences in the univariate results when<br />
possible duplicates were excluded. However, there were a few more substantial differences in<br />
the bivariate results in the smaller strata.<br />
On average, respondents who lived in Europe had used e-cigarettes for longer than respondents<br />
in the US, but were less likely to use e-cigarettes as a complete replacement for cigarettes (Table<br />
2). There was a positive relationship between the number of times participants had tried to stop<br />
smoking and using e-cigarettes as a complete replacement for cigarettes. Most (81%) of the<br />
4
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
respondents who indicated that pharmaceutical products did not help them stop smoking used ecigarettes<br />
as a complete replacement for cigarettes.<br />
Although the majority of respondents reported that their health and smoking-caused symptoms<br />
improved since using e-cigarettes, there were some notable trends in which groups were more<br />
likely to report improvements (Table 3). Respondents who had been using e-cigarettes for a<br />
longer period of time, who had completely replaced their cigarettes with e-cigarettes, or were<br />
younger were more likely to report improvements.<br />
Discussion<br />
This sample is mostly composed of people who tried to quit smoking and failed, but then<br />
succeeded in switching to e-cigarettes. This contradicts claims put forth by extremist nicotineabstinence<br />
proponents that e-cigarettes are appealing disproportionately to non-smokers and<br />
former smokers (supposedly as a result of marketing directed toward these groups, which also<br />
represents an unsubstantiated claim). There were only two respondents who indicated that they<br />
had quit permanently using pharmaceutical products and it is not known how long ago they quit<br />
or whether they would have resumed smoking if e-cigarettes were not available.<br />
Although few people responded that they use e-cigarettes in addition to cigarettes, there are a<br />
few noteworthy observations about this group of respondents. Some of these smokers may be<br />
supplementing their cigarette smoking with e-cigarette use in places where they are not allowed<br />
to smoke. It should be noted that this applies to no more than the 4% of the sample who<br />
indicated that they use e-cigarettes in addition to cigarettes. This is one of the main concerns that<br />
e-cigarettes opponents have voiced, though the objection to dedicated smokers seeking relief<br />
from time and place restrictions involves ethical claims that are seldom made and beyond the<br />
present scope [8]. It is not possible to determine whether the total nicotine intake increased for<br />
these respondents, as 75% had tried pharmaceutical quit smoking aids and it is possible that they<br />
replaced use of pharmaceutical nicotine products with e-cigarettes in places where they cannot<br />
smoke. The wording of these questions was rather imprecise (the exact wording of each question<br />
appears in Table 1) and may have resulted in misclassification and future surveys should attempt<br />
to quantify this by asking respondents to indicate the number of cigarettes that they smoked (per<br />
day) before using e-cigarettes and the number that they smoked after starting to use e-cigarettes,<br />
as well as when and where they smoke and use e-cigarettes. Approximately half of the few<br />
respondents who supplemented their cigarette use with e-cigarettes indicated that their general<br />
health was better since starting to use e-cigarettes. This could indicate misclassification (they<br />
actually reduced their smoking) or benefits of not suffering nicotine withdrawal symptoms in<br />
situations where they are not allowed to smoke.<br />
It is not surprising that none of the respondents indicated that their health got worse after they<br />
started using e-cigarettes, as this sample was very interested in, or in other words favourably<br />
disposed towards, e-cigarettes (given their participation in the e-cigarette forum and blogs). If<br />
people had started using e-cigarettes and their health got worse, they would likely have stopped<br />
using/purchasing e-cigarettes and therefore would not have been aware of the survey. Thus the<br />
results have to be seen as a proof of concept, but not an estimate of what portion of potential<br />
5
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
users receive the benefits. This study demonstrates that some e-cigarette users replace all or<br />
some of their cigarette use for e-cigarettes, and perceive health benefits subsequent to this<br />
behavioral change. E-cigarettes (like all other smoking cessation strategies) do not work for<br />
everyone, but this survey does demonstrate that e-cigarettes have enabled some people to quit<br />
smoking, including some people for whom other methods had proven ineffective. These health<br />
benefits will likely be reversed if the trend towards banning e-cigarettes continues and people<br />
who replaced e-cigarettes for cigarettes resume smoking.<br />
6
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 1: Preliminary results of the e-cigarette survey<br />
Whole sample Excluding possible<br />
(n=303) duplicates 1 (n=270)<br />
n % n %<br />
How old are you?<br />
18 – 30 39 13% 37 14%<br />
31 – 50 165 55% 148 55%<br />
>50 98 32% 84 31%<br />
Missing 1 1<br />
Please enter your country of residence:<br />
Europe 62 21% 43 16%<br />
USA 215 72% 206 77%<br />
Canada 8 3% 7 3%<br />
Australia/New Zealand 4 1% 4 1%<br />
Other 9 3% 7 3%<br />
Missing 5 -- 3<br />
Did you smoke before using the electronic cigarette?<br />
Yes 303 100% 270 100%<br />
No 0 0% 0 0%<br />
Missing 0 0<br />
How long have you been using electronic cigarettes?<br />
0 - 5 months 239 79% 210 78%<br />
6 - 12 months 54 18% 51 19%<br />
13 - 18 months 5 2% 5 2%<br />
19 - 24 months 1 0.3% 1 0.4%<br />
>24 months 3 1% 2 1%<br />
Missing 1 1<br />
Did you try to stop smoking before starting to use the<br />
electronic cigarette<br />
Yes 276 91% 248 92%<br />
No 26 9% 21 8%<br />
Missing 1 1<br />
If tried to stop smoking before starting to use the<br />
electronic cigarette:<br />
How many times did you try to stop smoking?<br />
1 - 3 times 95 35% 81 33%<br />
4 - 9 times 120 44% 113 46%<br />
>=10 times 58 21% 51 21%<br />
Missing 3 -- 3 --<br />
7
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 1: Preliminary results of the e-cigarette survey<br />
Whole sample Excluding possible<br />
(n=303) duplicates 1 (n=270)<br />
n % n %<br />
Did you ever try to use pharmaceutical products<br />
such as nicotine patches or nicotine gum to quit?<br />
Yes 236 86% 215 87%<br />
No 39 14% 32 13%<br />
Missing 1 -- 1 --<br />
If you ever tried to use pharmaceutical products<br />
such as nicotine patches or nicotine gum to quit?:<br />
Pharmaceutical Aids<br />
Helped me to stop smoking permanently. 2 1% 2 1%<br />
Helped me to stop smoking temporarily (
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 1: Preliminary results of the e-cigarette survey<br />
Whole sample Excluding possible<br />
(n=303) duplicates 1 (n=270)<br />
n % n %<br />
Worse 0 0% 0 0%<br />
Not applicable 26 -- 22 --<br />
Missing 10 -- 7 --<br />
How has your sense of smell changed since using the<br />
electronic cigarette?<br />
Better 235 80% 217 82%<br />
The same 58 20% 47 18%<br />
Worse 0 0% 0 0%<br />
Missing 10 -- 6 --<br />
How has your sense of taste changed since using the<br />
electronic cigarette?<br />
Better 216 73% 202 77%<br />
The same 78 27% 62 23%<br />
Worse 0 0% 0 0%<br />
Missing 9 -- 6 --<br />
1. Possible duplicates are all observations without IP address or e-mail address and 2 nd<br />
observation in each of 2 sets of observations with the same IP address.<br />
9
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of e-cigarette users (November 26, 2009): Heavner,<br />
Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 2: Use of electronic cigarettes (n=303)<br />
How long have you been using<br />
electronic cigarettes?(months)<br />
n 0-5 6-12 >12<br />
10<br />
Do you use the electronic cigarette:<br />
n In addition<br />
to cigarettes<br />
As a partial<br />
replacement<br />
for cigarettes<br />
How old are you?<br />
18 – 30 38 79% 21% 0% 38 5% 16% 79%<br />
31 – 50 165 80% 18% 2% 162 3% 18% 79%<br />
over 50 98 78% 17% 5% 95 6% 15% 79%<br />
Please enter your country of residence:<br />
Europe 62 69% 27% 3% 62 8% 26% 66%<br />
USA 214 81% 16% 2% 213 3% 13% 84%<br />
Canada 8 100% 0% 0% 8 12% 38% 50%<br />
Australia/New Zealand 4 50% 25% 25% 4 0% 0% 100%<br />
Other 9 89% 11% 0% 9 11% 33% 56%<br />
How long have you been using electronic<br />
cigarettes?<br />
0 - 5 months -- -- -- 234 4% 15% 81%<br />
6 - 12 months -- -- -- 54 6% 28% 67%<br />
>12 months -- -- -- 7 0% 0% 100%<br />
How many times did you try to stop smoking?<br />
0 times 26 88% 12% 0% 25 8% 20% 72%<br />
1 - 3 times 95 76% 20% 4% 93 3% 27% 70%<br />
4 - 9 times 119 80% 19% 1% 119 3% 14% 82%<br />
>=10 times 58 79% 16% 5% 57 7% 4% 89%<br />
Pharmaceutical aids<br />
Helped me to stop smoking permanently 2 100% 0% 0% 2 0% 0% 100%<br />
Helped me to stop smoking temporarily 46 72% 26% 2% 45 7% 24% 69%<br />
Helped me to reduce the amount I smoked,<br />
but did not help me to stop smoking<br />
38 87% 13% 0% 37 5% 14% 81%<br />
Did not help me to stop smoking 143 75% 20% 5% 142 3% 13% 84%<br />
As a complete<br />
replacement<br />
for cigarettes
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of e-cigarette users (November 26, 2009): Heavner,<br />
Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 2a: Use of electronic cigarettes, excluding potential duplicates (n=270)<br />
How long have you been using<br />
electronic cigarettes?(months)<br />
n 0-5 6-12 >12<br />
11<br />
Do you use the electronic cigarette:<br />
n In addition<br />
to cigarettes<br />
As a partial<br />
replacement<br />
for cigarettes<br />
How old are you?<br />
18 – 30 36 81% 19% 0% 36 6% 17% 78%<br />
31 – 50 148 78% 19% 3% 146 1% 18% 81%<br />
over 50 84 76% 19% 5% 82 4% 11% 85%<br />
Please enter your country of residence:<br />
Europe 43 58% 37% 5% 43 2% 28% 70%<br />
USA 168 82% 16% 2% 204 2% 13% 85%<br />
Canada 7 100% 0% 0% 7 14% 29% 57%<br />
Australia/New Zealand 4 50% 25% 25% 4 0% 0% 100%<br />
Other 7 86% 14% 0% 7 14% 14% 71%<br />
How long have you been using electronic<br />
cigarettes?<br />
0 - 5 months -- -- -- 207 2% 13% 85%<br />
6 - 12 months -- -- -- 51 4% 27% 69%<br />
>12 months -- -- -- 6 0% 0% 100%<br />
How many times did you try to stop smoking?<br />
0 times 21 86% 14% 0% 21 5% 19% 76%<br />
1 - 3 times 81 74% 21% 5% 80 2% 25% 72%<br />
4 - 9 times 112 79% 20% 1% 112 2% 14% 84%<br />
>=10 times 51 78% 18% 4% 50 4% 2% 94%<br />
Pharmaceutical aids<br />
Helped me to stop smoking permanently 2 100% 0% 0% 2 0% 0% 100%<br />
Helped me to stop smoking temporarily 39 72% 26% 3% 39 3% 28% 69%<br />
Helped me to reduce the amount I smoked,<br />
but did not help me to stop smoking<br />
34 85% 15% 0% 33 3% 12% 85%<br />
Did not help me to stop smoking 133 74% 21% 5% 132 2% 11% 87%<br />
As a complete<br />
replacement<br />
for cigarettes
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of e-cigarette users (November 26, 2009): Heavner,<br />
Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 3: Changes in health status and symptoms since using electronic cigarettes (n=303)<br />
Since starting to use<br />
the electronic<br />
cigarette, do you in<br />
general feel your<br />
health is:<br />
If you had a<br />
smoker's cough<br />
before using the<br />
electronic cigarette,<br />
is it now:<br />
12<br />
How has your ability<br />
to do exercise<br />
changed since using<br />
the electronic<br />
cigarette?<br />
How has your sense<br />
of smell changed<br />
since using the<br />
electronic cigarette?<br />
How has your sense<br />
of taste changed since<br />
using the electronic<br />
cigarette?<br />
n Better Same n Better Same n Better Same n Better Same n Better Same<br />
How old are you?<br />
18 – 30 38 97% 3% 30 100% 0% 35 94% 6% 48 89% 11% 38 87% 13%<br />
31 – 50 162 90% 10% 129 97% 3% 151 85% 15% 160 84% 16% 162 78% 22%<br />
over 50 94 88% 12% 72 97% 3% 80 79% 21% 94 70% 30% 93 60% 40%<br />
How long have you<br />
been using electronic<br />
cigarettes?<br />
0 - 5 months 233 89% 11% 182 97% 3% 210 81% 19% 232 79% 21% 232 72% 28%<br />
6 - 12 months 54 96% 4% 42 98% 2% 51 94% 6% 53 81% 19% 54 78% 22%<br />
>12 months 7 100% 0% 7 100% 0% 5 100% 0% 7 100% 0% 7 100% 0%<br />
Do you use the<br />
electronic cigarette:<br />
In addition to<br />
cigarettes<br />
As a partial<br />
replacement for<br />
cigarettes<br />
As a complete<br />
replacement for<br />
cigarettes<br />
11 55% 45% 9 78% 22% 9 56% 44% 12 42% 58% 12 25% 75%<br />
49 78% 22% 32 90% 9% 45 69% 31% 48 62% 38% 49 59% 41%<br />
234 95% 5% 190 99% 1% 212 89% 11% 232 86% 14% 232 79% 21%
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of e-cigarette users (November 26, 2009): Heavner,<br />
Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Table 3a: Changes in health status and symptoms since using electronic cigarettes, excluding potential duplicates (n=270)<br />
Since starting to use<br />
the electronic<br />
cigarette, do you in<br />
general feel your<br />
health is:<br />
If you had a<br />
smoker's cough<br />
before using the<br />
electronic cigarette,<br />
is it now:<br />
13<br />
How has your ability<br />
to do exercise<br />
changed since using<br />
the electronic<br />
cigarette?<br />
How has your sense<br />
of smell changed<br />
since using the<br />
electronic cigarette?<br />
How has your sense<br />
of taste changed since<br />
using the electronic<br />
cigarette?<br />
n Better Same n Better Same n Better Same n Better Same n Better Same<br />
How old are you?<br />
18 – 30 36 100% 0% 28 100% 0% 34 94% 6% 36 89% 11% 36 86% 14%<br />
31 – 50 147 93% 7% 119 97% 3% 136 89% 11% 145 86% 14% 146 82% 18%<br />
over 50 82 93% 7% 66 98% 2% 70 81% 19% 82 72% 28% 81 62% 38%<br />
How long have you<br />
been using electronic<br />
cigarettes?<br />
0 - 5 months 208 92% 8% 167 98% 2% 188 86% 14% 207 82% 18% 206 75% 25%<br />
6 - 12 months 51 98% 2% 40 98% 2% 48 94% 6% 50 82% 18% 51 78% 22%<br />
>12 months 6 100% 0% 6 100% 0% 4 100% 0% 6 100% 0% 6 100% 0%<br />
Do you use the<br />
electronic cigarette:<br />
In addition to<br />
cigarettes<br />
As a partial<br />
replacement for<br />
cigarettes<br />
As a complete<br />
replacement for<br />
cigarettes<br />
7 86% 14% 6 83% 17% 5 60% 40% 7 57% 43% 7 43% 57%<br />
41 80% 20% 29 93% 7% 38 71% 29% 40 62% 38% 41 59% 41%<br />
217 96% 4% 178 99% 1% 197 91% 9% 216 87% 13% 215 81% 19%
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
Acknowledgements and Competing Interests<br />
KH, PB, CN and CVP are interested in promoting tobacco harm reduction, and so our<br />
scientific selves have a relationship with our policy advocacy selves; the latter motivates our<br />
interest in this research. We periodically attempt to persuade corporations with marketing data to<br />
make that data available for scientific analysis and publishing; this project could help<br />
demonstrate the benefits of such actions. We have numerous contacts and constructive<br />
engagements with companies that make tobacco harm reduction products (which include<br />
smokeless tobacco companies and makers of e-cigarettes) and hope to receive funding from<br />
several of them in the future; it is not clear to us that any of them stands to benefit directly from<br />
this research because they generally have better data than the scientific community, but it is<br />
possible that we will report information that could be directly beneficial to one or more of them.<br />
CVP and his research group (which includes KH, PB and CN) are partially supported by an<br />
unrestricted (completely hands-off) grant to the University of Alberta School of Public Health<br />
from U.S. Smokeless Tobacco Company. The grantor is unaware of this study, and thus had no<br />
scientific input or other influence on it. JD owns 10% of E Cigarette Direct. CVP advises many<br />
organizations on tobacco harm reduction, some of which are corporations that could benefit from<br />
selling THR products, and is sometimes compensated for this work; he has consulted for U.S.<br />
Smokeless Tobacco Company in the context of product liability litigation. KH owns a small<br />
amount of stock in Johnson & Johnson.<br />
References<br />
1. Laugesen M. Safety Report on the Ruyan® e-cigarette Cartridge and Inhaled Aerosol. 10-<br />
30-2008. Christchurch, New Zealand, Health New Zealand Ltd.<br />
Ref Type: Report<br />
2. Phillips CV, Rabiu D, Rodu B: Calculating the comparative mortality risk from<br />
smokeless tobacco versus smoking. American Journal of Epidemiology 2006, 163: S189.<br />
3. Rodu B, Godshall WT: Tobacco harm reduction: an alternative cessation strategy for<br />
inveterate smokers. Harm Reduct J 2006, 3: 37.<br />
4. Phillips CV, Heavner K., Bergen P: Tobacco - the greatest untapped potential for harm<br />
reduction. In Harrm Reduction (forthcoming). 2010.<br />
5. Health Canada. Health Canada Advises Canadians Not to Use Electronic Cigarettes.<br />
http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/_2009/2009_53-eng.php . 3-27-<br />
2009. 11-16-2009.<br />
Ref Type: Electronic Citation<br />
14
Electronic cigarettes (e-cigarettes) as potential tobacco harm reduction products: Results of an online survey of ecigarette<br />
users (November 26, 2009): Heavner, Dunworth, Bergen, Nissen, Phillips<br />
Latest version available at: tobaccoharmreduction.org/wpapers/011.htm<br />
6. State Government of Victoria ADoHS. Victorian ban on battery-powered cigarette.<br />
http://hnb.dhs.vic.gov.au/web/pubaff/medrel.nsf/LinkView/3AA04FD559FB4ADACA257<br />
52F0079EB07?OpenDocument . 12-31-2008. 11-16-2009.<br />
Ref Type: Electronic Citation<br />
7. Kelton P. Suffolk Passes E-cigarette Ban. LongIslandPress.com . 8-18-2009.<br />
Ref Type: Newspaper<br />
8. Phillips CV. The affirmative ethical arguments for promoting a policy of tobacco<br />
harm reduction. 2009. 11-25-2009.<br />
Ref Type: Unpublished Work<br />
15
Nachschlagewerk zum Thema E-Zigaretten<br />
6 Preclinical safety evaluation of inhaled cyclo-<br />
sporine in propylene glycol.
http://www.ncbi.nlm.nih.gov/pubmed/18158714 1/2<br />
US National Library of Medicine<br />
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J Aerosol Med. 2007 Winter;20(4):417-28.<br />
Preclinical safety evaluation of inhaled cyclosporine in propylene glycol.<br />
Wang T, Noonberg S, Steigerwalt R, Lynch M, Kovelesky RA, Rodríguez CA, Sprugel K, Turner N.<br />
Novartis Pharmaceuticals, Safety Profiling and Assessment, Emeryville, California 94608, USA.<br />
tao.w ang@novartis.com<br />
Abstract<br />
Cyclosporine inhalation solution has the potential to improve outcomes following lung<br />
transplantation by delivering high concentrations of an immunosuppressant directly to the allograft<br />
while minimizing systemic drug exposure and associated toxicity. The objective of these studies<br />
was to evaluate the potential toxicity of aerosolized cyclosporine formulated in propylene glycol<br />
when given by inhalation route to rats and dogs for 28 days. Sprague-Dawley rats received total<br />
inhaled doses of 0 (air), 0 (vehicle, propylene glycol), 7.4, 24.3, and 53.9 mg cyclosporine/kg/day.<br />
In a separate study, beagle dogs were exposed to 0, 4.4, 7.7, and 9.7 mg cyclosporine/kg/day.<br />
Endpoints used to evaluate potential toxicity of inhaled cyclosporine were clinical observations,<br />
body weight, food consumption, respiratory functions, toxicokinetics, and clinical/anatomic<br />
pathology. Daily administration of aerosolized cyclosporine did not result in observable<br />
accumulation of cyclosporine in blood or lung tissue. Toxicokinetic analysis from the rat study<br />
showed that the exposure of cyclosporine was approximately 18 times higher in the lung tissue<br />
compared to the blood. Systemic effects were consistent with those known for cyclosporine. There<br />
was no unexpected systemic toxicity or clinically limiting local respiratory toxicity associated with<br />
inhalation exposure to cyclosporine inhalation solution at exposures up to 2.7 times the maximum<br />
human exposure in either rats or dogs. There were no respiratory or systemic effects of high doses<br />
of propylene glycol relative to air controls. These preclinical studies demonstrate the safety of<br />
aerosolized cyclosporine in propylene glycol and support its continued clinical investigation in<br />
patients undergoing allogeneic lung transplantation.<br />
PMID: 18158714 [PubMed - indexed for MEDLINE]<br />
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[J Aerosol cyclosporine Med Pulm in propylene Drug Deliv. glycol 2011]<br />
Non-clinical safety and<br />
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Nebulized cyclosporine for<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
7 Non-clinical safety and pharmacokinetic evalua-<br />
tions of propylene glycol aerosol in Sprague-<br />
Dawley rats and Beagle dogs.
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Toxicology. 2011 Sep 5;287(1-3):76-90. doi: 10.1016/j.tox.2011.05.015. Epub 2011 Jun 12.<br />
Non-clinical safety and pharmacokinetic evaluations of propylene glycol<br />
aerosol in Sprague-Dawley rats and Beagle dogs.<br />
Werley MS, McDonald P, Lilly P, Kirkpatrick D, Wallery J, Byron P, Venitz J.<br />
Altria Client Services, Inc., Center for Research and Technology, 601 East Jackson Street, Richmond, VA 23219-1434,<br />
USA. michael.s.w erley@altria.com<br />
Abstract<br />
Aerosolized propylene glycol (PG) was generated as log-normally distributed particulate clouds in<br />
different concentrations using a novel capillary aerosol generator (CAG) and evaluated in a battery<br />
of non-clinical studies intended to assess its potential inhalation and systemic toxicity in 2 species<br />
before ICH-compliant "first-time-in-man" studies. Exposures were nose-only in rats, and via face<br />
mask with oropharyngeal tube in dogs. The CAG-generated PG aerosol had a mass median<br />
aerodynamic diameter (MMAD) of 2.29μm, with a 1.56 geometric standard deviation (GSD) in the<br />
rat studies, and a MMAD of 1.34μm (1.45 GSD) in the dog studies, consistent with expected<br />
particle size exposures in man. International Congress on Harmonization (ICH) Guidelines were<br />
followed, which recommend preliminary non-clinical safety studies using the vehicle and device<br />
(CAG-PG) prior to the first human exposure including safety pharmacology, pharmacokinetic (PK)<br />
studies, single dose toxicity studies, and repeated dose toxicity studies in two species. In the rat,<br />
the only biologically relevant findings included clinical signs of ocular and nasal irritation indicated<br />
by minor bleeding around the eyes and nose, and minimal laryngeal squamous metaplasia. This<br />
finding is commonly observed in inhalation studies in the rat, and likely related to the unique<br />
sensitivity of the tissue, as well as the circuitous airflow pathway through the larynx which<br />
increases particle deposition. In the female Beagle dog, treatment-related decreases in hemoglobin,<br />
red blood cells and hematocrit were observed in the two highest exposure groups, equivalent to<br />
approximately 18 and 60mg/kg/day. In male dogs from the high dose group, similar small<br />
decreases, albeit, non-statistically significant decreases were observed in these hematological<br />
markers as well. PK studies in rats and dogs showed that the absorption of PG following pulmonary<br />
inhalation exposure occurs rapidly, and equilibrium between lung tissue and plasma is achieved<br />
quickly. With daily inhalations of PG aerosols, there is evidence of minor tissue accumulation of<br />
PG in each species. Inhalation exposure to CAG-generated PG aerosols achieved PG<br />
concentrations in the systemic circulation that were similar to those attained via the oral route.<br />
Systemic elimination of PG appears to be saturable, presumably via hepatic metabolism. PG<br />
elimination in the high dose groups for both species showed terminal plasma and lung<br />
concentration-time profiles suggesting a zero-order elimination process. There was no apparent<br />
tissue toxicity of the lung, liver and kidney in these studies. Under the conditions of these studies,<br />
the NOEL for the rat was determined to be 20mg/kg/day for the 28-day study. In the Beagle dog,<br />
the NOEL was approximately 6.05mg/kg/day for the 28-day study. Overall, these studies allowed us<br />
to conclude that PG aerosol generated with the capillary aerosol generator could be administered<br />
safely in man, with an adequate margin of safety needed to conduct "first-time-in-man" human<br />
exposure studies.<br />
Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.<br />
PMID: 21683116 [PubMed - indexed for MEDLINE]<br />
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Carcinogenesis Studies of Talc<br />
[Natl Toxicol Program Tech Rep Ser. 1993]<br />
NTP Toxicity Study Report on<br />
the atmospheric [Toxic Rep Ser. 2006]<br />
Preclinical safety evaluation of<br />
inhaled cyclosporine [J Aerosol inMed.<br />
2007]<br />
Review Triethylene glycol<br />
HO(CH2CH2O)3H. [J Appl Toxicol. 2007]<br />
Review Final report on the<br />
safety assessment [Int J Toxicol. of capsicum 2007]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
8 Variability among electronic cigarettes in the<br />
pressure drop, airflow rate, and aerosol produc-<br />
tion.
http://www.ncbi.nlm.nih.gov/pubmed/21994335 1/2<br />
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Nicotine Tob Res. 2011 Dec;13(12):1276-83. doi: 10.1093/ntr/ntr164. Epub 2011 Oct 12.<br />
Variability among electronic cigarettes in the pressure drop, airflow rate,<br />
and aerosol production.<br />
Williams M, Talbot P.<br />
Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA.<br />
Abstract<br />
INTRODUCTION: This study investigated the performance of electronic cigarettes (e-cigarettes),<br />
compared different models within a brand, compared identical copies of the same model within a<br />
brand, and examined performance using different protocols.<br />
METHODS: Airflow rate required to generate aerosol, pressure drop across e-cigarettes, and<br />
aerosol density were examined using three different protocols.<br />
PMID: 21994335 [PubMed - in process]<br />
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Search<br />
Citric acid aerosol as a potential<br />
smoking cessation aid. [Chest. 1987]<br />
Cigarette brand preference as a<br />
function of price [Tob among Control. smoking 2009]<br />
RESULTS: First 10 puff protocol: The airflow rate required to produce aerosol and aerosol density<br />
varied among brands, while pressure drop varied among brands and between the same model within<br />
Scope for regulation of cigarette<br />
smoke toxicity [N according Z Med J. to2005]<br />
a brand. Total air hole area correlated with pressure drop for some brands. Smoke-out protocol: E- Review Smoking behaviour and<br />
cigarettes within a brand generally performed similarly when puffed to exhaustion; however, there [Psychopharmacology compensation: a review (Berl). of the 1999]<br />
was considerable variation between brands in pressure drop, airflow rate required to produce Review Cigarettes with defective<br />
aerosol, and the total number of puffs produced. With this protocol, aerosol density varied<br />
filters marketed [Tob for Control. 40 years: 2002]<br />
significantly between puffs and gradually declined. CONSECUTIVE TRIAL PROTOCOL: Two copies<br />
of one model were subjected to 11 puffs in three consecutive trials with breaks between trials. One<br />
See reviews...<br />
copy performed similarly in each trial, while the second copy of the same model produced little<br />
aerosol during the third trial. The different performance properties of the two units were attributed to<br />
the atomizers.<br />
See all...<br />
CONCLUSION: There was significant variability between and within brands in the airflow rate Recent activity<br />
required to produce aerosol, pressure drop, length of time cartridges lasted, and production of<br />
Turn Off Clear<br />
aerosol. Variation in performance properties within brands suggests a need for better quality control Variability among electronic<br />
during e-cigarette manufacture.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
9 Short-term pulmonary effects of using an elec-<br />
tronic cigarette impact on respiratory flow re-<br />
sistance, impedance, and exhaled nitric oxide.
http://www.ncbi.nlm.nih.gov/pubmed/22194587 1/2<br />
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Chest. 2012 Jun;141(6):1400-6. doi: 10.1378/chest.11-2443. Epub 2011 Dec 22.<br />
Short-term pulmonary effects of using an electronic cigarette: impact on<br />
respiratory flow resistance, impedance, and exhaled nitric oxide.<br />
Vardavas CI, Anagnostopoulos N, Kougias M, Evangelopoulou V, Connolly GN, Behrakis PK.<br />
Center for Global Tobacco Control, Harvard School of Public Health, 677 Huntington Ave, Landmark, 3rd Floor E, Boston,<br />
MA 02115, USA. vardavas@hsph.harvard.edu<br />
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Abstract<br />
PubMed<br />
BACKGROUND: Debate exists over the scientific evidence for claims that electronic cigarettes (e-<br />
Short and long-term effects of<br />
cigarettes) have no health-related ramifications. This study aimed to assess whether using an e-<br />
cigarette [J Allergy smoking Clin Immunol. independently 2005]<br />
cigarette for 5 min has an impact on the pulmonary function tests and fraction of exhaled nitric<br />
oxide (Feno) of healthy adult smokers.<br />
Effect of smoking on exhaled<br />
nitric oxide and [Eur flow-independent<br />
Respir J. 2006]<br />
METHODS: Thirty healthy smokers (aged 19-56 years, 14 men) participated in this laboratory-<br />
[Airway inflammation and<br />
based experimental vs control group study. Ab lib use of an e-cigarette for 5 min with the cartridge<br />
[Zhonghua peripheral Jie He airway He Hu function Xi Za Zhi. in2009]<br />
included (experimental group, n = 30) or removed from the device (control group, n = 10) was<br />
assessed.<br />
Single breath N2-test and<br />
exhaled nitric oxide [Respir in Med. men. 2006]<br />
RESULTS: Using an e-cigarette for 5 min led to an immediate decrease in Feno within the<br />
experimental group by 2.14 ppb (P = .005) but not in the control group (P = .859). Total respiratory<br />
Acute pulmonary effects of<br />
sidestream secondhand [Xenobiotica. smoke 2012]<br />
impedance at 5 Hz in the experimental group was found to also increase by 0.033 kPa/(L/s) (P <<br />
.001), and flow respiratory resistance at 5 Hz, 10 Hz, and 20 Hz also statistically increased.<br />
See reviews...<br />
Regression analyses controlling for baseline measurements indicated a statistically significant<br />
See all...<br />
decrease in Feno and an increase in impedance by 0.04 kPa/(L/s) (P = .003), respiratory<br />
resistance at 5 Hz by 0.04 kPa/(L/s) (P = .003), at 10 Hz by 0.034 kPa/(L/s) (P = .008), at 20 Hz<br />
by 0.043 kPa/(L/s) (P = .007), and overall peripheral airway resistance (β, 0.042 kPa/[L/s]; P =<br />
Cited by 1 PubMed<br />
.024), after using an e-cigarette.<br />
Central article<br />
CONCLUSIONS: e-Cigarettes assessed in the context of this study were found to have immediate Chronic idiopathic neutrophilia in<br />
adverse physiologic effects after short-term use that are similar to some of the effects seen with [Clin a smoker, Med Insights relieved Case after Rep. smoking 2013]<br />
tobacco smoking; however, the long-term health effects of e-cigarette use are unknown but<br />
potentially adverse and worthy of further investigation.<br />
Comment in<br />
Electronic cigarettes: no such thing as a free lunch...Or puff. [Chest. 2012]<br />
PMID: 22194587 [PubMed - indexed for MEDLINE]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
10 Clinical laboratory assessment of the abuse lia-<br />
bility of an electronic cigarette.
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2012.03791.x/abstract 1/2<br />
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RESEARCH REPORT<br />
Clinical laboratory assessment of the abuse liability of an electronic<br />
cigarette<br />
Andrea R. Vansickel 1 , Michael F. Weaver 2 ,<br />
Thomas Eissenberg 3,*<br />
Article first published online: 8 MAY 2012<br />
DOI: 10.1111/j.1360-0443.2012.03791.x<br />
© 2012 The Authors, Addiction © 2012 Society<br />
for the Study of Addiction<br />
Additional Information (Show All)<br />
Abstract Article References Cited By<br />
Keywords:<br />
Abuse liability; abuse potential; electronic cigarettes; electronic nicotine delivery device; multiple choice<br />
procedure; nicotine; reinforcing effects; subjective effects<br />
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ABSTRACT<br />
Aims To provide an initial abuse liability assessment of an electronic cigarette (EC) in current tobacco cigarette smokers.<br />
Design The first of four within-subject sessions was an EC sampling session that involved six, 10-puff bouts (30 seconds inter-puff<br />
interval), each bout separated by 30 minutes. In the remaining three sessions participants made choices between 10 EC puffs and<br />
varying amounts of money, 10 EC puffs and a varying number of own brand cigarette (OB) puffs, or 10 OB puffs and varying amounts of<br />
money using the multiple-choice procedure (MCP). The MCP was completed six times at 30-minute intervals, and one choice was<br />
reinforced randomly at each trial.<br />
Setting Clinical laboratory.<br />
Participants Twenty current tobacco cigarette smokers.<br />
Measurements Sampling session outcome measures included plasma nicotine, cardiovascular response and subjective effects.<br />
Choice session outcome was the cross-over value on the MCP.<br />
Findings EC use resulted in significant nicotine delivery, tobacco abstinence symptom suppression and increased product acceptability<br />
ratings. On the MCP, participants chose to receive 10 EC puffs over an average of $1.06 or three OB puffs and chose 10 OB puffs over an<br />
average of $1.50 (P < 0.003).<br />
Conclusions Electronic cigarettes can deliver clinically significant amounts of nicotine and reduce cigarette abstinence symptoms and<br />
appear to have lower potential for abuse relative to traditional tobacco cigarettes, at least under certain laboratory conditions.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
11 Clinical laboratory model for evaluating the acute<br />
effects of electronic cigarettes.
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Cancer Epidemiol Biomarkers Prev. 2010 Aug;19(8):1945-53. doi: 10.1158/1055-9965.EPI-10-0288. Epub 2010 Jul 20.<br />
A clinical laboratory model for evaluating the acute effects of electronic<br />
"cigarettes": nicotine delivery profile and cardiovascular and subjective<br />
effects.<br />
Vansickel AR, Cobb CO, Weaver MF, Eissenberg TE.<br />
Virginia Commonw ealth University, Richmond, VA 23298, USA. teissenb@vcu.edu<br />
Abstract<br />
BACKGROUND: Electronic "cigarettes" are marketed to tobacco users as potential reduced<br />
exposure products (PREP), albeit with little information regarding electronic cigarette user toxicant<br />
exposure and effects. This information may be obtained by adapting clinical laboratory methods<br />
used to evaluate other PREPs for smokers.<br />
METHODS: Thirty-two smokers participated in four independent Latin-square ordered conditions<br />
that differed by product: own brand cigarette, "NPRO" electronic cigarettes (NPRO EC; 18 mg<br />
cartridge), "Hydro" electronic cigarettes (Hydro EC; 16 mg cartridge), or sham (unlit cigarette).<br />
Participants took 10 puffs at two separate times during each session. Plasma nicotine and carbon<br />
monoxide (CO) concentration, heart rate, and subjective effects were assessed.<br />
RESULTS: Own brand significantly increased plasma nicotine and CO concentration and heart rate<br />
within the first five minutes of administration whereas NPRO EC, Hydro EC, and sham smoking did<br />
not. Own brand, NPRO EC, and Hydro EC (but not sham) significantly decreased tobacco<br />
abstinence symptom ratings and increased product acceptability ratings. The magnitude of<br />
symptom suppression and increased acceptability was greater for own brand than for NPRO EC<br />
and Hydro EC.<br />
CONCLUSIONS: Under these acute testing conditions, neither of the electronic cigarettes exposed<br />
users to measurable levels of nicotine or CO, although both suppressed nicotine/tobacco<br />
abstinence symptom ratings.<br />
(c)2010 AACR.<br />
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Evaluating the acute effects of<br />
oral, non-combustible [Tob Control. potential 2010]<br />
Acute effects of Advance: a<br />
potential reduced [Tob exposure Control. 2002]<br />
IMPACT: This study illustrates how clinical laboratory methods can be used to understand the<br />
acute effects of these and other PREPs for tobacco users. The results and methods reported here<br />
Clinical laboratory assessment<br />
of the abuse liability [Addiction. of an 2012]<br />
will likely be relevant to the evaluation and empirically based regulation of electronic cigarettes and Review Smoking behaviour and<br />
similar products.<br />
[Psychopharmacology compensation: a review (Berl). of the 1999]<br />
Review Interventions to reduce<br />
[Cochrane harm from Database continued Syst tobacco Rev. 2007]<br />
Cited by 3 PubMed<br />
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Effect of an electronic nicotine<br />
delivery [BMC device Public (e-Cigarette) Health. 2011] on<br />
The scientific foundation for<br />
tobacco harm [Harm reduction, Reduct 2006- J. 2011]<br />
Electronic nicotine delivery<br />
systems: a research [Tob Control. agenda. 2011]<br />
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12 Commentary on Etter & Bullen (2011)
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 1/3<br />
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Commentary on Etter & Bullen (2011): Could E-cigs become the ultimate<br />
nicotine maintenance device?<br />
JONATHAN FOULDS 1 , SUSAN VELDHEER<br />
2<br />
Article first published online: 6 OCT 2011<br />
DOI: 10.1111/j.1360-0443.2011.03532.x<br />
© 2011 The Authors, Addiction © 2011 Society for<br />
the Study of Addiction<br />
Additional Information (Show All)<br />
Issue<br />
How to Cite Author Information Publication History<br />
Abstract Article References Cited By<br />
Addiction<br />
Keywords:<br />
Cessation; dependence; e-cigarette; electronic cigarette; nicotine; smoking<br />
Volume 106, Issue 11, pages<br />
2029–2030, November 2011<br />
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In this issue<br />
Advanced > Saved Searches ><br />
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Smoked tobacco products are the only legal products that kill half their consumers, and some of those around them, when used as<br />
Get PDF (77K)<br />
intended. More than 17 billion cigarettes are smoked world-wide every day, and that number continues to increase [1]. People smoke for<br />
the psychoactive and addictive effects of nicotine, but are killed by other toxins in the smoke [2,3].<br />
Almost 20 years ago in this journal, the following comment was made on ‘the ultimate nicotine replacement device’:<br />
If people have difficulty overcoming both nicotine dependence and long-term habit change, then surely the<br />
solution is to help them avoid most of the health risks with only a minimal alteration in their nicotine-seeking<br />
habits. This implies a nicotine replacement device which looks like a cigarette and delivers cigarette-like boli<br />
of nicotine, but does not deliver the tar and carbon monoxide which cause the vast majority of smoking-related<br />
disease . . . the development and promotion of such a product (and its eventual replacement of tobacco) could<br />
have massive beneficial public health implications lasting into the 21st century [4].<br />
Might electronic cigarettes (e-cigs) be the product that could replace regular cigarettes and prevent millions of premature deaths?<br />
Although e-cigs were perceived initially as something of a gimmick that was likely to be banned, their increasing popularity and resistance<br />
to regulatory efforts suggest that it is more likely they are here to stay.<br />
As e-cigs are sold largely via the internet, it is difficult to estimate total sales. Two US companies reported selling 735 000 e-cigs in just<br />
over a year [5], and among recent UK smokers 9% had used e-cigs and 3% were still using them [6]. In 2010, internet searches for e-cigs<br />
were several-hundred-fold greater than searches for medicinal nicotine therapy products [7]. E-cigs obviously look like a cigarette, and do<br />
not deliver tobacco tar or carbon monoxide, but questions remain about their nicotine delivery and regulatory status.<br />
Early laboratory studies of e-cigs found meager nicotine delivery [8,9]. However, Etter & Bullen [10] concluded that e-cigs are being used<br />
as aids to smoking cessation much as people use nicotine replacement medications. Preliminary results from a study in which<br />
experienced e-cig users were allowed to use their own (customized) e-cigs reported that they achieved cigarette-like increases in blood<br />
nicotine concentration (>10 ng/ml in 5 minutes) [11].<br />
This and other studies [10,12,13] suggest that some e-cigs are capable of cigarette-like nicotine delivery and so it is important that their<br />
potential to improve public health be given due consideration. Clearly, further research is necessary to clarify the best direction for e-cig<br />
regulation [14]. Electronic cigarettes are already banned in some countries (e.g. Brazil). Other countries have attempted to restrict their<br />
sale or importation (including the United States). Meanwhile, these same countries permit the sale of regular cigarettes, in the certainty<br />
that those real cigarettes will cause the premature death of about half of long-term users. Is banning the appropriate response to e-cigs<br />
while allowing toxic cigarettes to dominate the nicotine market?<br />
NOT REGISTERED ?<br />
FORGOTTEN PASSWORD ?<br />
INSTITUTIONAL LOGIN ><br />
E-cigs should be allowed to compete for the middle ground between highly toxic smoked tobacco products and smoking cessation<br />
medicines that have been demonstrated to be safe and effective for that purpose [15]. Thus e-cigs are currently competing for the smoke-<br />
free nicotine maintenance market, primarily against other smokeless tobacco products such as snuff, snus and dissolvable tobacco<br />
LOGIN<br />
Enter e-mail address<br />
Enter password<br />
REMEMBER ME
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 2/3<br />
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products [2,16,17]. How successful they are in competing in that market-place will depend upon whether manufacturers can mass-<br />
produce and market relatively low-cost, safe, reliable and user-friendly products with adequate nicotine delivery. They should be regulated<br />
to ensure that they do not deliver toxic chemicals unnecessary to their purpose (e.g. quality control measures should ensure no<br />
contaminants are in the liquid or vapor), and are as safe as technically possible (e.g. liquid should be in a child-proof container, and<br />
instructions for use should be clear and accurate) [18].<br />
Currently, the e-cig market is awash with numerous, sometimes low-quality products, and users need to navigate a personal and online<br />
learning curve to find a good product [13,18]. Improved quality-control, including assessment of nicotine delivery, will be necessary for<br />
smokers to be able to switch comfortably and confidently to e-cigs in large numbers.<br />
Tobacco regulation in the United States appears to be moving slowly towards the ‘reduced nicotine’ model [19]. This model would require<br />
cigarette manufacturers to reduce the nicotine content to the point where cigarettes are no longer addictive (current US legislation does<br />
not allow nicotine to be banned completely, but does allow any other chemical to be eliminated). E-cigs demonstrate the feasibility for a<br />
‘reduced toxin’ model, allowing nicotine to remain, but requiring manufacturers to eliminate delivery of the other toxic chemicals that harm<br />
health [3]. Whichever model prevails, it is unlikely to be successful if it does not provide smokers with an acceptable alternative nicotine<br />
product to switch to. E-cigs have the potential to become such a product.<br />
Declarations of interest<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
19<br />
Abstract PDF(188K) References Web of Science®<br />
Abstract Full Article (HTML) PDF(146K) References Web of Science®<br />
Abstract PDF(132K) References Web of Science® Times Cited: 31<br />
Jump to…<br />
Neither of the authors have any financial connections with the tobacco or electronic cigarette industries. Their salaries are paid by The<br />
Pennsylvania State University. J.F. has worked as a paid consultant for companies involved in the production of pharmaceutical products<br />
as aids to smoking cessation (e.g. Cypress Bioscience, GSK, Novartis, Pfizer) and as an expert witness in litigation against tobacco<br />
companies.<br />
References<br />
Jump to…<br />
Shafey O., Eriksen M., Ross H., Mackay J. The Tobacco Atlas, 3rd edn. Atlanta, GA: American Cancer Society; 2009.<br />
Royal College of Physicians (RCP). Harm reduction in nicotine addiction: helping people who can't quit. A report by the Tobacco<br />
Advisory Group of the Royal College of Physicians. London: RCP, 2007.<br />
Foulds J., Ghodse A. H. The role of nicotine in tobacco smoking: implications for tobacco control policy. J R Soc Health 1995; 115:<br />
225–30.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 6<br />
Foulds J. Nicotine replacement therapy does work: time to stop sitting on the fence. A reply . Addiction 1994; 89: 438–9.<br />
United States District Court for the District of Columbia. Smoking Everywhere, Inc., and Sottera, Inc. v. U.S. Food and Drug<br />
Administration et al. Memorandum Opinion by Judge Leon (p5) 2010 January 14. 2010; 09-771. Available at:<br />
http://ecf.dcd.uscourts.gov/cgi-bin/show_public_doc?2009cv0771-54 (accessed 14 July 2011; archived by Webcite at<br />
http://www.webcitation.org/61ieBo0gj).<br />
Dockrell M., Indu S. D., Lasjkari H. K., McNeill A. ‘It sounds like the replacement I need to help me stop smoking’: use and<br />
acceptability of ‘e-cigarettes’ among UK smokers. 12th annual meeting of the Society for Research on Nicotine and Tobacco<br />
Europe. Bath, UK; 2010. p.48. https://srnt.org/conferences/eu/eu_past/europdf/SRNTEu2010AbstractBook.pdf(accessed 14 July<br />
2011; archived by Webcite at http://www.webcitation.org/61ieJGTxx).<br />
Ayers J. W., Ribisl K. M., Brownstein J. S. Tracking the rise in popularity of electronic nicotine delivery systems (electronic<br />
cigarettes) using search query surveillance. Am J Prev Med 2011; 40: 448–53.<br />
CrossRef, PubMed, Web of Science® Times Cited: 4<br />
Bullen C., McRobbie H., Thornley S., Glover M., Lin R., Laugesen M. Effect of an electronic nicotine delivery device (e cigarette) on<br />
desire to smoke and withdrawal, user preferences and nicotine delivery: randomised cross-over trial. Tob Control 2010; 19:<br />
98–103.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 15<br />
Vansickel A. R., Cobb C. O., Weaver M. F., Eissenberg T. E. A clinical laboratory model for evaluating the acute effects of electronic<br />
‘cigarettes’: nicotine delivery profile and cardiovascular and subjective effects. Cancer Epidemiol Biomarkers Prev 2010; 19:<br />
1945–53.<br />
CrossRef, PubMed, Web of Science® Times Cited: 5<br />
Etter J. F., Bullen C. Electronic cigarettes: users profile, utilization, satisfaction and perceived efficacy. Addiction 2011; 106:<br />
2017–28.<br />
Vansickel A. R., Blank M., Cobb C., Kilgalen B., Austin J., Weaver M. et al. Clinical laboratory model for evaluating the effects of<br />
electronic ‘cigarettes’. February 2011; 17th Annual Meeting of the Society for Research on Nicotine and Tobacco. Toronto, Canada,<br />
2011.<br />
Foulds J., Veldheer S., Berg A. Electronic cigarettes (e-cigs): views of aficionados and clinical/public health perspectives . Int J Clin<br />
Pract 2011; 65: 1037–42.<br />
McQueen A., Tower S., Sumner W. Interviews with ‘Vapers’: implications for future research with electronic cigarettes. Nicotine Tob<br />
Res 2011; Epub ahead of print. doi:10.1093/ntr/ntr088.<br />
CrossRef, PubMed, Web of Science®<br />
Etter J. F., Bullen C., Flouris A. D., Laugesen M., Eissenberg T. Electronic nicotine delivery systems: a research agenda. Tob<br />
Control 2011; 20: 243–8.<br />
CrossRef, PubMed, Web of Science® Times Cited: 1<br />
Foulds J., Steinberg M. B., Williams J. M., Ziedonis D. M. Developments in pharmacotherapy for tobacco dependence: past,<br />
present and future. Drug Alcohol Rev 2006; 25: 59–71.<br />
Foulds J., Kozlowski L. Snus—what should the public-health response be? Lancet 2007; 369: 1976–8.<br />
CrossRef, PubMed, Web of Science® Times Cited: 16<br />
Ramstrom L. M., Foulds J. Role of snus in initiation and cessation of tobacco smoking in Sweden . Tob Control 2006; 15: 210–4.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 62<br />
Trtchounian A., Talbot P. Electronic nicotine delivery systems: is there a need for regulation? Tob Control 2011; 20: 47–52.<br />
CrossRef, PubMed, Web of Science® Times Cited: 1<br />
Hatsukami D. K., Perkins K. A., Lesage M. G., Ashley D. L., Henningfield J. E., Benowitz N. L. et al. Nicotine reduction revisited:
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 3/3<br />
science and future directions. Tob Control 2010; 19: e1–10.<br />
CrossRef, PubMed, Web of Science® Times Cited: 2<br />
More content like this<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
13 Conventional and electronic cigarettes (e-<br />
cigarettes) have different smoking characteris-<br />
tics.
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 1/3<br />
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Commentary on Etter & Bullen (2011): Could E-cigs become the ultimate<br />
nicotine maintenance device?<br />
JONATHAN FOULDS 1 , SUSAN VELDHEER<br />
2<br />
Article first published online: 6 OCT 2011<br />
DOI: 10.1111/j.1360-0443.2011.03532.x<br />
© 2011 The Authors, Addiction © 2011 Society for<br />
the Study of Addiction<br />
Additional Information (Show All)<br />
Issue<br />
How to Cite Author Information Publication History<br />
Abstract Article References Cited By<br />
Addiction<br />
Keywords:<br />
Cessation; dependence; e-cigarette; electronic cigarette; nicotine; smoking<br />
Volume 106, Issue 11, pages<br />
2029–2030, November 2011<br />
SEARCH<br />
In this issue<br />
Advanced > Saved Searches ><br />
ARTICLE TOOLS<br />
Get PDF (77K)<br />
Save to My Profile<br />
E-mail Link to this Article<br />
Export Citation for this Article<br />
Get Citation Alerts<br />
Request Permissions<br />
Share |<br />
Smoked tobacco products are the only legal products that kill half their consumers, and some of those around them, when used as<br />
Get PDF (77K)<br />
intended. More than 17 billion cigarettes are smoked world-wide every day, and that number continues to increase [1]. People smoke for<br />
the psychoactive and addictive effects of nicotine, but are killed by other toxins in the smoke [2,3].<br />
Almost 20 years ago in this journal, the following comment was made on ‘the ultimate nicotine replacement device’:<br />
If people have difficulty overcoming both nicotine dependence and long-term habit change, then surely the<br />
solution is to help them avoid most of the health risks with only a minimal alteration in their nicotine-seeking<br />
habits. This implies a nicotine replacement device which looks like a cigarette and delivers cigarette-like boli<br />
of nicotine, but does not deliver the tar and carbon monoxide which cause the vast majority of smoking-related<br />
disease . . . the development and promotion of such a product (and its eventual replacement of tobacco) could<br />
have massive beneficial public health implications lasting into the 21st century [4].<br />
Might electronic cigarettes (e-cigs) be the product that could replace regular cigarettes and prevent millions of premature deaths?<br />
Although e-cigs were perceived initially as something of a gimmick that was likely to be banned, their increasing popularity and resistance<br />
to regulatory efforts suggest that it is more likely they are here to stay.<br />
As e-cigs are sold largely via the internet, it is difficult to estimate total sales. Two US companies reported selling 735 000 e-cigs in just<br />
over a year [5], and among recent UK smokers 9% had used e-cigs and 3% were still using them [6]. In 2010, internet searches for e-cigs<br />
were several-hundred-fold greater than searches for medicinal nicotine therapy products [7]. E-cigs obviously look like a cigarette, and do<br />
not deliver tobacco tar or carbon monoxide, but questions remain about their nicotine delivery and regulatory status.<br />
Early laboratory studies of e-cigs found meager nicotine delivery [8,9]. However, Etter & Bullen [10] concluded that e-cigs are being used<br />
as aids to smoking cessation much as people use nicotine replacement medications. Preliminary results from a study in which<br />
experienced e-cig users were allowed to use their own (customized) e-cigs reported that they achieved cigarette-like increases in blood<br />
nicotine concentration (>10 ng/ml in 5 minutes) [11].<br />
This and other studies [10,12,13] suggest that some e-cigs are capable of cigarette-like nicotine delivery and so it is important that their<br />
potential to improve public health be given due consideration. Clearly, further research is necessary to clarify the best direction for e-cig<br />
regulation [14]. Electronic cigarettes are already banned in some countries (e.g. Brazil). Other countries have attempted to restrict their<br />
sale or importation (including the United States). Meanwhile, these same countries permit the sale of regular cigarettes, in the certainty<br />
that those real cigarettes will cause the premature death of about half of long-term users. Is banning the appropriate response to e-cigs<br />
while allowing toxic cigarettes to dominate the nicotine market?<br />
NOT REGISTERED ?<br />
FORGOTTEN PASSWORD ?<br />
INSTITUTIONAL LOGIN ><br />
E-cigs should be allowed to compete for the middle ground between highly toxic smoked tobacco products and smoking cessation<br />
medicines that have been demonstrated to be safe and effective for that purpose [15]. Thus e-cigs are currently competing for the smoke-<br />
free nicotine maintenance market, primarily against other smokeless tobacco products such as snuff, snus and dissolvable tobacco<br />
LOGIN<br />
Enter e-mail address<br />
Enter password<br />
REMEMBER ME
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 2/3<br />
Wiley Job Network<br />
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the Wiley Job Netw ork<br />
products [2,16,17]. How successful they are in competing in that market-place will depend upon whether manufacturers can mass-<br />
produce and market relatively low-cost, safe, reliable and user-friendly products with adequate nicotine delivery. They should be regulated<br />
to ensure that they do not deliver toxic chemicals unnecessary to their purpose (e.g. quality control measures should ensure no<br />
contaminants are in the liquid or vapor), and are as safe as technically possible (e.g. liquid should be in a child-proof container, and<br />
instructions for use should be clear and accurate) [18].<br />
Currently, the e-cig market is awash with numerous, sometimes low-quality products, and users need to navigate a personal and online<br />
learning curve to find a good product [13,18]. Improved quality-control, including assessment of nicotine delivery, will be necessary for<br />
smokers to be able to switch comfortably and confidently to e-cigs in large numbers.<br />
Tobacco regulation in the United States appears to be moving slowly towards the ‘reduced nicotine’ model [19]. This model would require<br />
cigarette manufacturers to reduce the nicotine content to the point where cigarettes are no longer addictive (current US legislation does<br />
not allow nicotine to be banned completely, but does allow any other chemical to be eliminated). E-cigs demonstrate the feasibility for a<br />
‘reduced toxin’ model, allowing nicotine to remain, but requiring manufacturers to eliminate delivery of the other toxic chemicals that harm<br />
health [3]. Whichever model prevails, it is unlikely to be successful if it does not provide smokers with an acceptable alternative nicotine<br />
product to switch to. E-cigs have the potential to become such a product.<br />
Declarations of interest<br />
1<br />
2<br />
3<br />
4<br />
5<br />
6<br />
7<br />
8<br />
9<br />
10<br />
11<br />
12<br />
13<br />
14<br />
15<br />
16<br />
17<br />
18<br />
19<br />
Abstract PDF(188K) References Web of Science®<br />
Abstract Full Article (HTML) PDF(146K) References Web of Science®<br />
Abstract PDF(132K) References Web of Science® Times Cited: 31<br />
Jump to…<br />
Neither of the authors have any financial connections with the tobacco or electronic cigarette industries. Their salaries are paid by The<br />
Pennsylvania State University. J.F. has worked as a paid consultant for companies involved in the production of pharmaceutical products<br />
as aids to smoking cessation (e.g. Cypress Bioscience, GSK, Novartis, Pfizer) and as an expert witness in litigation against tobacco<br />
companies.<br />
References<br />
Jump to…<br />
Shafey O., Eriksen M., Ross H., Mackay J. The Tobacco Atlas, 3rd edn. Atlanta, GA: American Cancer Society; 2009.<br />
Royal College of Physicians (RCP). Harm reduction in nicotine addiction: helping people who can't quit. A report by the Tobacco<br />
Advisory Group of the Royal College of Physicians. London: RCP, 2007.<br />
Foulds J., Ghodse A. H. The role of nicotine in tobacco smoking: implications for tobacco control policy. J R Soc Health 1995; 115:<br />
225–30.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 6<br />
Foulds J. Nicotine replacement therapy does work: time to stop sitting on the fence. A reply . Addiction 1994; 89: 438–9.<br />
United States District Court for the District of Columbia. Smoking Everywhere, Inc., and Sottera, Inc. v. U.S. Food and Drug<br />
Administration et al. Memorandum Opinion by Judge Leon (p5) 2010 January 14. 2010; 09-771. Available at:<br />
http://ecf.dcd.uscourts.gov/cgi-bin/show_public_doc?2009cv0771-54 (accessed 14 July 2011; archived by Webcite at<br />
http://www.webcitation.org/61ieBo0gj).<br />
Dockrell M., Indu S. D., Lasjkari H. K., McNeill A. ‘It sounds like the replacement I need to help me stop smoking’: use and<br />
acceptability of ‘e-cigarettes’ among UK smokers. 12th annual meeting of the Society for Research on Nicotine and Tobacco<br />
Europe. Bath, UK; 2010. p.48. https://srnt.org/conferences/eu/eu_past/europdf/SRNTEu2010AbstractBook.pdf(accessed 14 July<br />
2011; archived by Webcite at http://www.webcitation.org/61ieJGTxx).<br />
Ayers J. W., Ribisl K. M., Brownstein J. S. Tracking the rise in popularity of electronic nicotine delivery systems (electronic<br />
cigarettes) using search query surveillance. Am J Prev Med 2011; 40: 448–53.<br />
CrossRef, PubMed, Web of Science® Times Cited: 4<br />
Bullen C., McRobbie H., Thornley S., Glover M., Lin R., Laugesen M. Effect of an electronic nicotine delivery device (e cigarette) on<br />
desire to smoke and withdrawal, user preferences and nicotine delivery: randomised cross-over trial. Tob Control 2010; 19:<br />
98–103.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 15<br />
Vansickel A. R., Cobb C. O., Weaver M. F., Eissenberg T. E. A clinical laboratory model for evaluating the acute effects of electronic<br />
‘cigarettes’: nicotine delivery profile and cardiovascular and subjective effects. Cancer Epidemiol Biomarkers Prev 2010; 19:<br />
1945–53.<br />
CrossRef, PubMed, Web of Science® Times Cited: 5<br />
Etter J. F., Bullen C. Electronic cigarettes: users profile, utilization, satisfaction and perceived efficacy. Addiction 2011; 106:<br />
2017–28.<br />
Vansickel A. R., Blank M., Cobb C., Kilgalen B., Austin J., Weaver M. et al. Clinical laboratory model for evaluating the effects of<br />
electronic ‘cigarettes’. February 2011; 17th Annual Meeting of the Society for Research on Nicotine and Tobacco. Toronto, Canada,<br />
2011.<br />
Foulds J., Veldheer S., Berg A. Electronic cigarettes (e-cigs): views of aficionados and clinical/public health perspectives . Int J Clin<br />
Pract 2011; 65: 1037–42.<br />
McQueen A., Tower S., Sumner W. Interviews with ‘Vapers’: implications for future research with electronic cigarettes. Nicotine Tob<br />
Res 2011; Epub ahead of print. doi:10.1093/ntr/ntr088.<br />
CrossRef, PubMed, Web of Science®<br />
Etter J. F., Bullen C., Flouris A. D., Laugesen M., Eissenberg T. Electronic nicotine delivery systems: a research agenda. Tob<br />
Control 2011; 20: 243–8.<br />
CrossRef, PubMed, Web of Science® Times Cited: 1<br />
Foulds J., Steinberg M. B., Williams J. M., Ziedonis D. M. Developments in pharmacotherapy for tobacco dependence: past,<br />
present and future. Drug Alcohol Rev 2006; 25: 59–71.<br />
Foulds J., Kozlowski L. Snus—what should the public-health response be? Lancet 2007; 369: 1976–8.<br />
CrossRef, PubMed, Web of Science® Times Cited: 16<br />
Ramstrom L. M., Foulds J. Role of snus in initiation and cessation of tobacco smoking in Sweden . Tob Control 2006; 15: 210–4.<br />
CrossRef, PubMed, CAS, Web of Science® Times Cited: 62<br />
Trtchounian A., Talbot P. Electronic nicotine delivery systems: is there a need for regulation? Tob Control 2011; 20: 47–52.<br />
CrossRef, PubMed, Web of Science® Times Cited: 1<br />
Hatsukami D. K., Perkins K. A., Lesage M. G., Ashley D. L., Henningfield J. E., Benowitz N. L. et al. Nicotine reduction revisited:
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03532.x/full 3/3<br />
science and future directions. Tob Control 2010; 19: e1–10.<br />
CrossRef, PubMed, Web of Science® Times Cited: 2<br />
More content like this<br />
Find more content: like this article<br />
Find more content written by:<br />
JONATHAN FOULDS SUSAN VELDHEER All Authors<br />
ABOUT US HELP CONTACT US AGENTS ADVERTISERS MEDIA PRIVACY COOKIES TERMS & CONDITIONS SITE MAP<br />
Copyright © 1999–2013 John Wiley & Sons, Inc. All Rights Reserved.<br />
Get PDF (77K)
Nachschlagewerk zum Thema E-Zigaretten<br />
14 Electronic cigarettes as a smoking-cessation<br />
tool results from an online survey.
http://www.ncbi.nlm.nih.gov/pubmed/21406283 1/2<br />
US National Library of Medicine<br />
National Institutes of Health<br />
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Am J Prev Med. 2011 Apr;40(4):472-5. doi: 10.1016/j.amepre.2010.12.006.<br />
Electronic cigarettes as a smoking-cessation: tool results from an online<br />
survey.<br />
Siegel MB, Tanwar KL, Wood KS.<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Department of Community Health Sciences, Boston University School of Public Health, Boston, Massachusetts 02118,<br />
USA. mbsiegel@bu.edu<br />
Abstract<br />
BACKGROUND: Electronic cigarettes (e-cigarettes) are battery-powered devices that deliver<br />
nicotine without any combustion or smoke. These devices have generated much publicity among<br />
the smoking-cessation community and support from dedicated users; however, little is known about<br />
the efficacy of the device as a smoking-cessation tool.<br />
PURPOSE: This study aimed to examine the effectiveness of e-cigarettes for smoking cessation<br />
using a survey of smokers who had tried e-cigarettes.<br />
METHODS: Using as a sampling frame a cohort of all first-time purchasers of a particular brand of<br />
e-cigarettes during a 2-week period, a cross-sectional, online survey was conducted in 2010 to<br />
describe e-cigarette use patterns and their effectiveness as a smoking-cessation tool. There were<br />
222 respondents, with a survey response rate of 4.5%. The primary outcome variable was the point<br />
prevalence of smoking abstinence at 6 months after initial e-cigarette purchase.<br />
RESULTS: The primary finding was that the 6-month point prevalence of smoking abstinence<br />
among the e-cigarette users in the sample was 31.0% (95% CI=24.8%, 37.2%). A large percentage<br />
of respondents reported a reduction in the number of cigarettes they smoked (66.8%) and almost<br />
half reported abstinence from smoking for a period of time (48.8%). Those respondents using ecigarettes<br />
more than 20 times per day had a quit rate of 70.0%. Of respondents who were not<br />
smoking at 6 months, 34.3% were not using e-cigarettes or any nicotine-containing products at the<br />
time.<br />
CONCLUSIONS: Findings suggest that e-cigarettes may hold promise as a smoking-cessation<br />
method and that they are worthy of further study using more-rigorous research designs.<br />
Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights<br />
reserved.<br />
PMID: 21406283 [PubMed - indexed for MEDLINE]<br />
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Electronic cigarette: users<br />
profile, utilization, [Addiction. satisfaction 2011]<br />
Review The emerging<br />
phenomenon [Expert Rev of Respir electronic Med. 2012]<br />
Smoking cessation services in<br />
U.S. methadone [Psychiatr maintenance Serv. 2004]<br />
Electronic cigarettes: a survey of<br />
users.[BMC Public Health. 2010]<br />
Review A review of the efficacy<br />
of smoking-cessation [Clin Ther. 2008]<br />
Cited by 1 PubMed<br />
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15 e-Cigarette awareness, use, and harm percep-<br />
tions in US adults
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Am J Prev Med. 2011 Apr;40(4):472-5. doi: 10.1016/j.amepre.2010.12.006.<br />
Electronic cigarettes as a smoking-cessation: tool results from an online<br />
survey.<br />
Siegel MB, Tanwar KL, Wood KS.<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Department of Community Health Sciences, Boston University School of Public Health, Boston, Massachusetts 02118,<br />
USA. mbsiegel@bu.edu<br />
Abstract<br />
BACKGROUND: Electronic cigarettes (e-cigarettes) are battery-powered devices that deliver<br />
nicotine without any combustion or smoke. These devices have generated much publicity among<br />
the smoking-cessation community and support from dedicated users; however, little is known about<br />
the efficacy of the device as a smoking-cessation tool.<br />
PURPOSE: This study aimed to examine the effectiveness of e-cigarettes for smoking cessation<br />
using a survey of smokers who had tried e-cigarettes.<br />
METHODS: Using as a sampling frame a cohort of all first-time purchasers of a particular brand of<br />
e-cigarettes during a 2-week period, a cross-sectional, online survey was conducted in 2010 to<br />
describe e-cigarette use patterns and their effectiveness as a smoking-cessation tool. There were<br />
222 respondents, with a survey response rate of 4.5%. The primary outcome variable was the point<br />
prevalence of smoking abstinence at 6 months after initial e-cigarette purchase.<br />
RESULTS: The primary finding was that the 6-month point prevalence of smoking abstinence<br />
among the e-cigarette users in the sample was 31.0% (95% CI=24.8%, 37.2%). A large percentage<br />
of respondents reported a reduction in the number of cigarettes they smoked (66.8%) and almost<br />
half reported abstinence from smoking for a period of time (48.8%). Those respondents using ecigarettes<br />
more than 20 times per day had a quit rate of 70.0%. Of respondents who were not<br />
smoking at 6 months, 34.3% were not using e-cigarettes or any nicotine-containing products at the<br />
time.<br />
CONCLUSIONS: Findings suggest that e-cigarettes may hold promise as a smoking-cessation<br />
method and that they are worthy of further study using more-rigorous research designs.<br />
Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights<br />
reserved.<br />
PMID: 21406283 [PubMed - indexed for MEDLINE]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
16 Effect of an electronic nicotine delivery device e-<br />
Cigarette on smoking reduction and cessation a<br />
prospective 6-month pilot study.
http://www.ncbi.nlm.nih.gov/pubmed/21989407 1/2<br />
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BMC Public Health. 2011 Oct 11;11:786. doi: 10.1186/1471-2458-11-786.<br />
Effect of an electronic nicotine delivery device (e-Cigarette) on smoking<br />
reduction and cessation: a prospective 6-month pilot study.<br />
Polosa R, Caponnetto P, Morjaria JB, Papale G, Campagna D, Russo C.<br />
Centro per la Prevenzione e Cura del Tabagismo (CPCT), Azienda Ospedaliero-Universitaria Policlinico-Vittorio<br />
Emanuele, Università di Catania, Catania, Italy. polosa@unict.it<br />
Abstract<br />
BACKGROUND: Cigarette smoking is a tough addiction to break. Therefore, improved approaches<br />
to smoking cessation are necessary. The electronic-cigarette (e-Cigarette), a battery-powered<br />
electronic nicotine delivery device (ENDD) resembling a cigarette, may help smokers to remain<br />
abstinent during their quit attempt or to reduce cigarette consumption. Efficacy and safety of these<br />
devices in long-term smoking cessation and/or smoking reduction studies have never been<br />
investigated.<br />
PMID: 21989407 [PubMed - indexed for MEDLINE] PMCID: PMC3203079 Free PMC Article<br />
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METHODS: In this prospective proof-of-concept study we monitored possible modifications in<br />
smoking habits of 40 regular smokers (unwilling to quit) experimenting the 'Categoria' e-Cigarette<br />
with a focus on smoking reduction and smoking abstinence. Study participants were invited to<br />
attend a total of five study visits: at baseline, week-4, week-8, week-12 and week-24. Product use,<br />
number of cigarettes smoked, and exhaled carbon monoxide (eCO) levels were measured at each<br />
visit. Smoking reduction and abstinence rates were calculated. Adverse events and product<br />
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RESULTS: Sustained 50% reduction in the number of cig/day at week-24 was shown in<br />
PubMed<br />
13/40(32.5%) participants; their median of 25 cigs/day decreasing to 6 cigs/day (p < 0.001). Impact of an electronic cigarette<br />
Sustained 80% reduction was shown in 5/40(12.5%) participants; their median of 30 cigs/day [Int J on Environ smoking Res reduction Public Health. and 2013]<br />
decreasing to 3 cigs/day (p = 0.043). Sustained smoking abstinence at week-24 was observed in<br />
9/40(22.5%) participants, with 6/9 still using the e-Cigarette by the end of the study. Combined<br />
sustained 50% reduction and smoking abstinence was shown in 22/40 (55%) participants, with an<br />
Smoking cessation or reduction<br />
with nicotine [BMC Public replacement Health. 2009]<br />
overall 88% fall in cigs/day. Mouth (20.6%) and throat (32.4%) irritation, and dry cough (32.4%)<br />
were common, but diminished substantially by week-24. Overall, 2 to 3 cartridges/day were used<br />
Review [Smoking reduction and<br />
temporary abstinence: [J Mal Vasc. new 2003]<br />
throughout the study. Participants' perception and acceptance of the product was good.<br />
Effect of an electronic nicotine<br />
CONCLUSION: The use of e-Cigarette substantially decreased cigarette consumption without<br />
delivery device [Tob (e cigarette) Control. 2010] on<br />
causing significant side effects in smokers not intending to quit (http://ClinicalTrials.gov number Review A review of the efficacy<br />
NCT01195597).<br />
of smoking-cessation [Clin Ther. 2008]<br />
Cited by 1 PubMed<br />
Central article<br />
See reviews...<br />
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Successful smoking cessation<br />
with electronic [J Med cigarettes Case Rep. in 2011]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
17 Interviews with vapers implications for future re-<br />
search with electronic cigarettes.
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Nicotine Tob Res. 2011 Sep;13(9):860-7. doi: 10.1093/ntr/ntr088. Epub 2011 May 12.<br />
Interviews with "vapers": implications for future research with electronic<br />
cigarettes.<br />
McQueen A, Tower S, Sumner W.<br />
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Department of Medidicne School of Medicine, Washington University, St. Louis, MO 63108, USA.<br />
amcqueen@dom.w ustl.edu<br />
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Abstract<br />
PubMed<br />
INTRODUCTION: Awareness and use of electronic cigarettes (e-cigs) has increased dramatically.<br />
Electronic cigarettes (e-cigs):<br />
Electronic Nicotine Delivery Devices deliver an aerosol comprised usually of water, propylene glycol views of aficionados [Int J Clin and Pract. 2011]<br />
and/or glycerin, nicotine, and flavorings. Scant research exists to evaluate the efficacy and safety of<br />
Electronic cigarette: users<br />
such devices, and only one quantitative survey of European users (N = 81) has been published.<br />
profile, utilization, [Addiction. satisfaction 2011]<br />
This qualitative study explores e-cig users' ("vapers") experiences.<br />
Effect of an electronic nicotine<br />
METHODS: Participants attended a convention or club meeting in St. Louis, MO, and were<br />
delivery [BMC device Public (e-Cigarette) Health. 2011] on<br />
interviewed individually or in small groups. Qualitative methods were used to analyze interview data<br />
for both deductive and emergent themes to broad research questions.<br />
Review 'Cut down to quit' with<br />
nicotine [Health replacement Technol Assess. therapies 2008] in<br />
RESULTS: Even with a relatively small sample of formal participants (N = 15), there were pervasive<br />
Review Nicotine transdermal<br />
themes including the language and culture of vaping; social and informational support among vapers<br />
[Methods systems: Find Exp pharmaceutical Clin Pharmacol. and 2000]<br />
and their use of Internet resources (learning about e-cigs); the learning curve to using e-cigs and the<br />
numerous modifications ("mods") available for e-cigs and personal vaporizers; motives and<br />
See reviews...<br />
perceived benefits of using e-cigs versus cigarettes including cigarette-like enjoyment, cost,<br />
See all...<br />
restored sense of taste and smell, and improved breathing and exercise tolerance; rapidly reduced<br />
nicotine tolerance and dependence; and a strong interest in e-cig-related research and policy.<br />
Conclusions: The learning curve to using e-cigs has important implications for laboratory tests of<br />
Related information<br />
these devices with novice users. Similarly, the multiple e-cig options and the use of "mods" create<br />
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challenges for researchers and policy makers. Transdisciplinary research is urgently needed, and<br />
experienced "vapers" are very interested and willing research participants.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
18 A clinical laboratory model for evaluating the<br />
acute effects of electronic cigarettes nicotine de-<br />
livery profile and cardiovascular and subjective<br />
effects.
http://www.ncbi.nlm.nih.gov/pubmed/20647410 1/2<br />
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Cancer Epidemiol Biomarkers Prev. 2010 Aug;19(8):1945-53. doi: 10.1158/1055-9965.EPI-10-0288. Epub 2010 Jul 20.<br />
A clinical laboratory model for evaluating the acute effects of electronic<br />
"cigarettes": nicotine delivery profile and cardiovascular and subjective<br />
effects.<br />
Vansickel AR, Cobb CO, Weaver MF, Eissenberg TE.<br />
Virginia Commonw ealth University, Richmond, VA 23298, USA. teissenb@vcu.edu<br />
Abstract<br />
BACKGROUND: Electronic "cigarettes" are marketed to tobacco users as potential reduced<br />
exposure products (PREP), albeit with little information regarding electronic cigarette user toxicant<br />
exposure and effects. This information may be obtained by adapting clinical laboratory methods<br />
used to evaluate other PREPs for smokers.<br />
METHODS: Thirty-two smokers participated in four independent Latin-square ordered conditions<br />
that differed by product: own brand cigarette, "NPRO" electronic cigarettes (NPRO EC; 18 mg<br />
cartridge), "Hydro" electronic cigarettes (Hydro EC; 16 mg cartridge), or sham (unlit cigarette).<br />
Participants took 10 puffs at two separate times during each session. Plasma nicotine and carbon<br />
monoxide (CO) concentration, heart rate, and subjective effects were assessed.<br />
RESULTS: Own brand significantly increased plasma nicotine and CO concentration and heart rate<br />
within the first five minutes of administration whereas NPRO EC, Hydro EC, and sham smoking did<br />
not. Own brand, NPRO EC, and Hydro EC (but not sham) significantly decreased tobacco<br />
abstinence symptom ratings and increased product acceptability ratings. The magnitude of<br />
symptom suppression and increased acceptability was greater for own brand than for NPRO EC<br />
and Hydro EC.<br />
CONCLUSIONS: Under these acute testing conditions, neither of the electronic cigarettes exposed<br />
users to measurable levels of nicotine or CO, although both suppressed nicotine/tobacco<br />
abstinence symptom ratings.<br />
(c)2010 AACR.<br />
PubMed<br />
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oral, non-combustible [Tob Control. potential 2010]<br />
Acute effects of Advance: a<br />
potential reduced [Tob exposure Control. 2002]<br />
IMPACT: This study illustrates how clinical laboratory methods can be used to understand the<br />
acute effects of these and other PREPs for tobacco users. The results and methods reported here<br />
Clinical laboratory assessment<br />
of the abuse liability [Addiction. of an 2012]<br />
will likely be relevant to the evaluation and empirically based regulation of electronic cigarettes and Review Smoking behaviour and<br />
similar products.<br />
[Psychopharmacology compensation: a review (Berl). of the 1999]<br />
Review Interventions to reduce<br />
[Cochrane harm from Database continued Syst tobacco Rev. 2007]<br />
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delivery [BMC device Public (e-Cigarette) Health. 2011] on<br />
The scientific foundation for<br />
tobacco harm [Harm reduction, Reduct 2006- J. 2011]<br />
Electronic nicotine delivery<br />
systems: a research [Tob Control. agenda. 2011]<br />
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19 Electronic nicotine delivery devices ineffective<br />
nicotine delivery and craving suppression after<br />
acute administration.
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Tob Control. 2010 Feb;19(1):87-8. doi: 10.1136/tc.2009.033498.<br />
Electronic nicotine delivery devices: ineffective nicotine delivery and<br />
craving suppression after acute administration.<br />
Eissenberg T.<br />
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20 Public Health Challenges of Electronic Cigarettes<br />
in South Korea.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249262/ 1/5<br />
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Journal List > J Prev Med Public Health > v.44(6); Nov 2011 > PMC3249262<br />
J Prev Med Public Health. 2011 November; 44(6): 235–241.<br />
Published online 2011 November 14. doi: 10.3961/jpmph.2011.44.6.235<br />
Public Health Challenges of Electronic Cigarettes in South Korea<br />
Sungkyu Lee, 1 Heejin Kimm, 2 Ji Eun Yun, 2 and Sun Ha Jee 2<br />
Author information ► Article notes ► Copyright and License information ►<br />
Abstract<br />
PMCID: PMC3249262<br />
Electronic cigarettes (e-cigarrettes) were recently introduced and advertised as a smoking cession device in South<br />
Korea. As the social norm to quit smoking has gained hold in the country, the number of e-cigarette users is growing<br />
rapidly. This phenomenon should be urgently considered, because of the lack of research that has been conducted to<br />
examine the safety of e-cigarettes and its efficacy as a smoking cessation aid.<br />
This paper raises several public health concerns on e-cigarettes in South Korea. Uncertain regulations of the<br />
government on e-cigarettes are contributing to an increase of e-cigarette users and allowing the e-cigarette industry to<br />
circumvent existing regulations. The aggressive marketing activity of this industry is also a core factor that is<br />
responsible for the rapid increase of e-cigarette use, in particular among the youth. Following the enforcement of<br />
tobacco control, some cigarette smokers may be encouraged to purchase e-cigarettes in order to circumvent the<br />
regulations, even though the dual use of e-cigarette and cigarette may be more harmful.<br />
Go to:<br />
Until there is clear evidence of the e-cigarette's safety, it is recommended that the industry's marketing and promotional<br />
activities be banned and closely monitored, and public campaigns be initiated to educate the public regarding ecigarettes.<br />
Keywords: Electronic cigarettes, Electronic nicotine delivery systems, Tobacco<br />
INTRODUCTION<br />
Tobacco use is a leading cause of preventable illness and is responsible for more than 40 000 deaths annually in South<br />
Korea [1]. In the early 1980s, it was estimated that 8 out of 10 Korean men smoked cigarettes [2]. Additionally,<br />
cigarettes were commonly viewed as something to be enjoyed, similar to an individual's preference for a "favourite<br />
food," rather than as a harmful product. However, along with the rapid economic growth during the 1990s, concerns<br />
about tobacco use and its harmful effects on health have become hugely widespread throughout the country. This has<br />
resulted in a rapid decrease of the overall smoking rate, as shown in Table 1 [2]. Notably, the introduction of the "wellbeing"<br />
life trend in the early 2000s placed a high priority on achieving and maintaining one's health, which accelerated<br />
anti-smoking and tobacco control activities. Intensive efforts to reduce tobacco use have also been conducted by the<br />
government and public health professionals, leading to the implementation of strong and effective tobacco control<br />
policies and measures, such as tobacco tax increases, media campaigns, and ratification of Framework Convention on<br />
Tobacco Control [3]. As a result, the number of smokers who want to quit has significantly increased; according to the<br />
2010 National Actual Smoking Survey, approximately 60% of Korean current smokers indicated a desire to quit<br />
smoking [4].<br />
Table 1<br />
Smoking prevalence of Korea's adult over 20 years old, 1980-2008 (%)<br />
Go to:<br />
If these smokers were able to quit based purely on their desire to do so, a rapid decrease in the smoking prevalence in<br />
Korea would certainly be observed. However, previous studies indicate that given the behaviours or habits driven by<br />
nicotine addiction, many smokers who wish to quit can easily relapse and continue their smoking habit [5,6]. This is also<br />
true for Korean smokers. Nearly 70% of smokers in South Korea say they are still smoking, because smoking has<br />
become their "habit" [4]. Once an individual initiates smoking, nicotine is absorbed into the bloodstream within 10 to 15<br />
seconds, and flows immediately to the brain, where nicotine works to produce a range of gratifying effects [7].<br />
Through this process, smokers experience pleasure, cognitive enhancement, relaxation, and reduction in anxiety [10-12].<br />
As an individual continues to smoke, the amount of nicotine required to experience these effects is increased, leading to<br />
an increase in the number of cigarettes smoked in order to achieve the desired effect, ultimately causing nicotine<br />
addiction. For this reason, health professionals have focused on counselling, education, and medicinal nicotine<br />
replacement products (available as gum and patches) in order to treat nicotine addiction and to encourage cessation<br />
among smokers attempting to quit.<br />
Recently, the electronic cigarette (Figure 1) (referred to as e-cigarettes hereafter) was introduced and advertised as an<br />
"incredible smoking cession device" in the South Korean market. On advertisements, e-cigarettes are described as<br />
"healthy cigarettes" [13]. Emphasis is also placed on the lack of withdrawal symptoms that e-cigarette users<br />
experience, thus making it attractive to current smokers looking to quit [14]. Following the context that quitting smoking<br />
may become the social norm as more than half of current smokers want to quit their smoking habit [4], and given that<br />
the products are currently advertised as an effective smoking cession device [15], it is not surprising that the amount of<br />
e-cigarette imports is growing rapidly [16]. In addition, it is assumed that youth and young people are more likely to be<br />
targeted by the e-cigarette industry, and a rapid rise in the number of youth e-cigarette users is also being observed by<br />
mass media [16]. This phenomenon should be urgently and intensively considered, because of the lack of research that<br />
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Related citations in PubMed<br />
Electronic cigarette: users profile, utilization, satisfaction and<br />
perceived efficacy. [Addiction. 2011]<br />
Permissive nicotine regulation as a complement to traditional<br />
tobacco control. [BMC Public Health. 2005]<br />
Youth tobacco surveillance--United States, 2000.<br />
[MMWR CDC Surveill Summ. 2001]<br />
[Tobacco control in South Africa].<br />
[Promot Educ. 2005]<br />
Reducing the addictiveness of cigarettes. Council on Scientific<br />
Affairs, American Medical Association. [Tob Control. 1998]<br />
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SimSmoke model evaluation of the effect of tobacco control<br />
policies in Korea: the unknown success [Am story. J Public Health. 2010]<br />
Review Pharmacology of nicotine: addiction and therapeutics.<br />
[Annu Rev Pharmacol Toxicol. 1996]<br />
Review Genetic variability in nicotinic acetylcholine receptors<br />
and nicotine addiction: converging evidence [Behav from Brain human Res. and 2008]<br />
animal research.<br />
Smoking produces rapid rise of [11C]nicotine in human brain.<br />
[Psychopharmacology (Berl). 2010]<br />
Review Cigarette smoking and panic: a critical review of the<br />
literature. [J Clin Psychiatry. 2010]<br />
Review Smoking and smoking cessation -- the relationship<br />
between cardiovascular disease and lipoprotein [Atherosclerosis. metabolism: 2008] a<br />
review.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249262/ 2/5<br />
has been conducted to examine the safety of e-cigarettes and its efficacy, if any, as a smoking cessation aid.<br />
Figure 1<br />
E-cigarette component diagram.<br />
Based on this background, this commentary paper discusses the public health challenges of e-cigarettes in South Korea<br />
and suggests a number of clear and important recommendations for comprehensive control on e-cigarettes.<br />
E-CIGARETTES: BRIEF INTRODUCTION AND CONTROVERSIAL ISSUES<br />
Go to:<br />
In recent years, e-cigarettes have been introduced to the global market. This device was invented by Ruyan Group<br />
(Holdings) Limited, China in 2003, and the company patented e-cigarettes in Canada in 2004 [17]. E-cigarettes look like<br />
real cigarettes, but do not burn and combust tobacco leaves; thus, the e-cigarette manufacturers and distributors insist<br />
that it is safer than other tobacco products. The device consists of a plastic tube, an electronic heating element, a liquid<br />
nicotine cartridge, a lithium battery, and atomization chamber with a membrane to suspend ingredients [18]. It also has<br />
an LED-generated red light to simulate the burning end of a cigarette. Because of the lack of combustion involved in<br />
an e-cigarette, the device does not deliver tar or chemical elements that are present in regular cigarettes that are known<br />
to cause and increase the risk of developing cardiovascular and pulmonary diseases. Instead, there is a replaceable<br />
cartridge containing nicotine (with the ability of the user to adjust the nicotine concentration), chemical additives, and<br />
flavours (e.g. chocolate, coffee, mint, fruits). As the user exhales, some visible vapour is released, but no tobacco<br />
smoke. With these features, the e-cigarette industry insists that the device is safe, can be used in non-smoking areas,<br />
and is free from second-hand smoke concerns.<br />
Are e-cigarettes truly safe? Can they be used as a smoking cessation aid as the industry advertises? There is a lack of<br />
scientific evidence offering clear answers to these questions. There are a few short-term studies that have investigated<br />
e-cigarettes [19,20], but the evidence is not sufficient to conclusively end the controversial debates on the safety of ecigarettes.<br />
Despite the lack of scientific evidence to confirm the e-cigarette industry's claims of safety, e-cigarettes are<br />
being sold and distributed throughout South Korea and worldwide. The World Health Organisation (WHO) and the US<br />
Food and Drug Administration (US FDA) have warned against the widespread use of e-cigarettes as a nicotine<br />
replacement product. Both bodies have recognised that e-cigarettes may be less harmful than tobacco smoking, given<br />
the lack of tar in e-cigarettes, but they emphasise that e-cigarettes are almost certainly more dangerous than medicinal<br />
nicotine replacement products [19,20].<br />
The WHO defines that the e-cigarette as an electronic nicotine delivery system (ENDS). The Organisation not only<br />
recommends that ENDS be treated differently from traditional tobacco products, but also recommends that until<br />
conclusive evidence shows that e-cigarettes are safe, they should not be marketed as a nicotine replacement product,<br />
and that marketing activities of the e-cigarette manufacturers and distributors must be strictly controlled [19].<br />
The US FDA has attempted to treat e-cigarettes as a drug-delivery device under the Food, Drug, and Cosmetic Act<br />
since January 2010. As a result, e-cigarette manufacturers were required to submit an application for evaluation and<br />
approval of their device before they could be marketed to the public. This decision was based on US FDA's research<br />
showing that e-cigarettes contained carcinogens, including nitrosamines, toxic chemicals, such as diethylene glycol, and<br />
tobacco-specific components suspected of being harmful to humans, such as anabasine, myosmine, and beta-nicotyrine<br />
[20]. However, the US Court of Appeals ruled that the FDA lacked the authority to regulate e-cigarettes as drugs or<br />
devices on 6th December 2010. In response, the FDA announced that e-cigarettes would be regulated as a tobacco<br />
product [21]. Meanwhile, given the lack of evidence regarding e-cigarettes' safety or efficacy as a smoking cessation<br />
aid, Australia, Canada, Singapore, and Brazil have banned the sale of e-cigarettes [19].<br />
There is some research to support that e-cigarettes are effective in reducing the desire to smoke; however, this<br />
research was funded by Ruyan Group (Holdings) Limited. In this study, 40 participants were randomised to use ecigarettes<br />
containing 16 mg nicotine, placebo e-cigarettes, or medicinal nicotine inhalators for four days. The results<br />
indicated that there was no difference in reducing desire to smoke between a 16 mg e-cigarette and an inhalator, which<br />
can be interpreted to mean that e-cigarettes probably work similarly to medicinal nicotine replacement inhalators. In<br />
addition, the 16 mg e-cigarettes were found to be more pleasant to use than a nicotine inhalator [22]. Not surprisingly,<br />
these findings support the e-cigarette industry in advertising their device as a smoking cessation aid.<br />
Although a few studies are available, given the absence of evaluation of e-cigarettes for longer-term safety, potential<br />
effects of long-term use and efficacy as a smoking cessation aid, uncertainty on e-cigarettes still remain. As such, more<br />
careful and comprehensive control polices and measures on e-cigarettes are urgently needed to prevent unexpected<br />
public health impacts.<br />
PUBLIC HEALTH CONCERNS OF E-CIGARETTES IN SOUTH KOREA<br />
I. Uncertainty in the Regulations<br />
E-cigarettes have been imported to South Korea since 2007, and the total volume of imports have rapidly increased to<br />
more than three times in mid-2011, compared to 2008 [15]. Following the recent upward trend of e-cigarette sales, the<br />
Korean government urgently considered how to regulate the new device and the decision was made to place ecigarettes<br />
under the jurisdiction of two separate government bodies. On the one hand, e-cigarettes which contain<br />
nicotine have been registered by the Ministry of Finance (MOF) as same as a cigarette product since 2010. The MOF<br />
has revised the Tobacco Business Act (enacted in 1989), added e-cigarettes as a type of cigarette, and also levied<br />
health promotion tax on e-cigarettes. However, e-cigarettes containing no nicotine were placed under the jurisdiction of<br />
the Korea Food and Drug Administration (KFDA) as a health supplement, and were named "electronic smoking desire<br />
reducers."<br />
Up until 2002, the MOF ran the domestic mono-polised tobacco company, Korea Tobacco and Ginseng Corporation,<br />
and still maintains a good relationship with the tobacco industry to this present day. In 1989, the Tobacco Business Act<br />
was legislated and enacted to foster tobacco business, which gave the MOF the opportunity to encourage tobacco<br />
business, due to the tax revenue. Because of this relationship and potential conflict of interest, e-cigarette surveillance<br />
via the MOF and the Tobacco Business Act may not be the most reliable or effective.<br />
Meanwhile, the KFDA authorised the sales of e-cigarettes containing no nicotine as an "electronic smoking desire<br />
Go to:<br />
E-cigarettes: a rapidly growing Internet phenomenon.<br />
[Ann Intern Med. 2010]<br />
E-cigarette or drug-delivery device? Regulating novel nicotine<br />
products. [N Engl J Med. 2011]<br />
Effect of an electronic nicotine delivery device (e cigarette) on<br />
desire to smoke and withdrawal, user preferences [Tob Control. and nicotine 2010]<br />
delivery: randomised cross-over trial.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249262/ 3/5<br />
reducer." Although the KFDA officially stated that the safety of e-cigarettes and its efficacy as a smoking cessation aid<br />
have not yet been scientifically proven, the e-cigarette industry currently advertises their products with a message<br />
claiming that "E-cigarettes are authorised by the KFDA, thus it is safe" [23]. In fact, the KFDA's authorisation of the<br />
sales of e-cigarettes is misleading to the public and has potential threats to public health.<br />
Uncertain regulations and policies of the Korean government on e-cigarettes are contributing to an increase of ecigarette<br />
users in the country and also allow the e-cigarette manufacturers and distributors to circumvent existing<br />
regulations.<br />
II. E-cigarette Use Among Youths<br />
At present, no research studies have been conducted to examine the actual e-cigarette prevalence in South Korea, but<br />
it has already been widely assumed by the media that the number of e-cigarette users is rapidly increasing, particularly<br />
among youth. One such report indicates that 20% of the total e-cigarette sales in South Korea are contributed by youth<br />
users [16]. In addition, the report describes youth e-cigarette users often enjoying the device in the classroom and<br />
during class time, and that youth users will frequently exchange cartridges with other youth users in order to experience<br />
and enjoy the different flavours of e-cigarettes [16]. In the beginning of e-cigarette sales in Korea, expensive price of<br />
the device (about US$ 200-300) took a role as a barrier to youth access, however, following the competitive market<br />
environment, the industry has introduced a cheaper price range device (US$ 100 -150) to the market. Thus, price itself<br />
can no longer be relied on as a barrier to youth access.<br />
Evidence in the literature indicates that the most important factors for youth smoking initiation are having friends who<br />
smoke and being exposed to smoking offers from close friends [24-26]. Because of the increasing popularity of ecigarettes<br />
among Korean youth, non-smoking youth who have friends who use e-cigarettes are likely to be susceptible<br />
to initiate smoking e-cigarettes. In addition, the e-cigarette packaging may be attractive and fashionable to youth, who<br />
may be further tempted to try it. Compared to adult users who may decide to use e-cigarettes for the purpose of<br />
quitting, youth users are more likely to use e-cigarettes for the novelty factor. Of particular concern is the ability of the<br />
e-cigarette user to adjust the nicotine concentration, as youth users may not be aware that they can experience<br />
symptoms of nicotine addiction much more rapidly than adults [27,28]. Therefore, it is important to understand youth<br />
users' behaviours with e-cigarettes, and the impact of e-cigarettes of e-cigarette on youth should be carefully and<br />
quickly considered by policy makers and public health experts.<br />
III. Aggressive Marketing Activities<br />
The aggressive marketing activity of e-cigarette manufacturers and distributors is one of the core factors that may be<br />
responsible for the rapid increase of e-cigarette use in South Korea. The WHO and US FDA have already addressed<br />
their concerns about the aggressive marketing activities of e-cigarette companies in their reports. Until conclusive<br />
scientific evidence of safety and efficacy of e-cigarettes is released, all marketing activities of the e-cigarette industry<br />
should be banned [19,20]. Despite the viewpoints of the WHO and US FDA, the industry is quick to advertise that ecigarettes<br />
can be an effective smoking cessation aid by employing "above-the-line" and "below-the-line" marketing<br />
tactics in South Korea. As previously mentioned, given that e-cigarettes with nicotine are regulated in the same way as<br />
a cigarette by the Tobacco Business Act in South Korea, the e-cigarette industry's marketing activities should be limited<br />
as follows: (1) E-cigarette promotions, such as free samples or the displaying of posters, stickers, and signboards<br />
promoting e-cigarettes, should only be available in e-cigarette retail shops; (2) advertisements should only be permitted<br />
at point-of-sale locations; (3) any kind of e-cigarette advertising using broadcast media, such as TV and radio, should be<br />
prohibited, but placement of 120 advertisements per e-cigarette brand family in magazines, except magazines<br />
specifically targeted to women or youth, would still be possible under the Tobacco Business Act; and (4) sponsorship of<br />
social, cultural, musical, athletic, and other specific events, except events targeted to women or youth, would still be<br />
possible for the e-cigarette industry.<br />
The most common and powerful marketing tactics of the e-cigarette industry include the use of internet websites and<br />
blogs to sell and promote their products. Importantly, internet blogs allow the industry to achieve two-way<br />
communication between themselves and existing / future consumers. These strategies of e-cigarette companies can be<br />
seen to be contributing to the rapid increase of e-cigarette use in South Korea. Internet blogs are a familiar, easily<br />
accessible, and unrestricted media for youth to learn about what e-cigarettes are, where to buy cheaper e-cigarettes,<br />
and how to buy e-cigarettes without national ID cards. In addition, the use of the internet to locate information is<br />
commonplace; for example, a simple internet search within NAVER, the nation's largest internet portal site, with the<br />
keyword searching term, "electronic cigarette" indentified almost 850 legitimate retail websites (accessed at 18th July<br />
2011), in which the majority of the websites were run by e-cigarette manufacturers, distributors, and local retailers. The<br />
same keyword search on NAVER's blog search engine identified 40 422 blog sites (access at 18th July 2011). To date,<br />
no investigation has been conducted to examine whether these seemingly independent internet websites and blogs are<br />
being used by the e-cigarette industry as one of their aggressive marketing tactics. It should also be noted that all of the<br />
information in the e-cigarette internet websites and blogs are open and accessible to youth under the age of 18.<br />
IV. Dual Use of Cigarettes and E-cigarettes: Undermining Tobacco Control Policies and Regulations<br />
Dual use of e-cigarettes and traditional cigarettes should be examined, as smokers who do not wish to quit can easily<br />
use an e-cigarette as an alternative in non-smoking areas. Recently, through the nationwide enforcement of tobacco<br />
control policies and regulations in South Korea, areas designated as non-smoking are expanding. In Seoul, the capital<br />
city of South Korea, some major squares (public outdoor places) are designated as non-smoking areas. As trends are<br />
beginning to indicate that smoking is increasingly becoming socially unacceptable in South Korea, it is anticipated that<br />
the next step in expanding non-smoking areas would include prohibiting smoking in every indoor places, including<br />
restaurants and bars. Given the restrictions on public smoking, some cigarette smokers may be encouraged to purchase<br />
e-cigarettes in order to circumvent the tobacco control regulations, as the e-cigarette industry encourages dual use by<br />
advertising that the public use of e-cigarettes is not restricted and is therefore legal to use in restaurants, bars, and other<br />
indoor areas where cigarette smoking is strictly prohibited.<br />
V. Recommendations<br />
Further research investigating the effects of e-cigarettes must be conducted in order to conclusively determine the<br />
safety of this product. In addition, these studies should be conducted independently and should not be sponsored or<br />
funded by the e-cigarette industry. Descriptive studies to investigate the current prevalence of e-cigarette use among<br />
The Korean prediction model for adolescents' future smoking<br />
intentions. [J Prev Med Public Health. 2010]<br />
Parents' and friends' smoking status as predictors of smoking<br />
onset: findings from six European countries. [Health Educ Res. 2003]<br />
Diminished autonomy over tobacco can appear with the first<br />
cigarettes. [Addict Behav. 2008]
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249262/ 4/5<br />
adults and youths and to explore current e-cigarette users' behaviours and attitudes should be performed. In order to<br />
determine the safety of long-term use and efficacy as a smoking cessation aid, longitudinal cohort studies should also be<br />
conducted. E-cigarette initiation among non-smokers and their behaviour changes are an important topic to be<br />
examined. In addition, the industry's retail websites and internet blogs which include e-cigarette information should be<br />
also examined and regulated in terms of what health messages they provide and how this information affects potential<br />
users.<br />
Until there is clear evidence of the e-cigarette's safety, it is recommended that the industry's marketing and promotional<br />
activities be banned, in agreement with the recommendations of the WHO and the US FDA. However, a complete<br />
banning and regulation of these activities may take a long length of time to enact; as such, restrictions, particularly on<br />
youth access and youth-centred marketing of e-cigarettes, should be in place until such a ban can be put into effect.<br />
With no restrictions in place concerning the e-cigarette industry's marketing activities, the prevalence of e-cigarette<br />
users continues to rapidly grow in South Korea. This is cause for concern, as the e-cigarette industry may employ<br />
tactics used by transnational tobacco companies in order to exert influence on government policies and for legislation<br />
and regulations to be largely made in their favour [29,30]. It is possible that the e-cigarette industry currently lobbies<br />
policy makers, and uses third parties, such as consumer groups, in order to undermine regulations that are not<br />
favourable in order to continue their business. Therefore, the e-cigarette industry should be closely observed and<br />
monitored. In recent years, it has been discovered that Philip Morris International (PMI), the one of the largest tobacco<br />
manufacturers in the world, attempted to negotiate with Ruyan Group, which manufactured the original e-cigarettes<br />
[31]. The motives of PMI are not clear, but it is suspected that the transnational tobacco companies have a great deal<br />
of interest in for the acquisition of e-cigarette markets.<br />
Furthermore, educational campaigns should be initiated in order to educate the public regarding e-cigarettes and to<br />
provide correct information. Not only does the industry's marketing tactics and misleading health information on their<br />
websites (for example, e-cigarette is a "healthy cigarette" and it helps to quit smoking without withdrawal symptoms, as<br />
mentioned above) raise serious public health concerns, but users who describe their experiences with e-cigarettes on<br />
their internet blogs may unknowingly be providing misinformation, which also impacts public health by potentially<br />
attracting new e-cigarette users. Therefore, the government, public health professionals, tobacco control advocates, and<br />
non-government organisations must conduct educational campaigns to inform the public regarding the use of ecigarettes.<br />
In addition, the National Quit Line, physicians in smoking cessation clinics, school teachers, and other<br />
individuals who have opportunities to meet and counsel current smokers who want to quit should discourage the use of<br />
e-cigarettes as a smoking cessation aid until there is enough scientific evidence to support this claim.<br />
ACKNOWLEDGEMENTS<br />
The authors are grateful to Professor Il Soon Kim, Dr. Joann Lee, and Professor Hong Kwan Seo for reviewing the<br />
manuscript.<br />
Funding: This study was supported by a grant of the Seoul R&BD program (10526), Korea.<br />
Footnotes<br />
The authors have no conflicts of interest with the material presented in this paper.<br />
This article is available at http://jpmph.org/.<br />
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3. Levy DT, Cho SI, Kim YM, Park S, Suh MK, Kam S. SimSmoke model evaluation of the effect of tobacco control<br />
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5. Benowitz NL. Pharmacology of nicotine: addiction and therapeutics. Annu Rev Pharmacol Toxicol. 1996;36:597<br />
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9. E-cigarette. Ruyan Korea. [cited 2011 Jul 10]. Available from: http://ruyankorea.co.kr/sub02/index.htm.<br />
10. Cosci F, Knuts IJ, Abrams K, Griez EJ, Schruers KR. Cigarette smoking and panic: a critical review of the<br />
literature. J Clin Psychiatry. 2010;71(5):606–615. [PubMed]<br />
11. Metz CN, Gregersen PK, Malhotra AK. Metabolism and biochemical effects of nicotine for primary care providers.<br />
Med Clin North Am. 2004;88(6):1399–1413. ix. [PubMed]<br />
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cardiovascular disease and lipoprotein metabolism: a review. Atherosclerosis. 2008;201(2):225–235. [PubMed]<br />
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aid=20110616002450&subctg1=&subctg2=<br />
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19. World Health Organization, Study Group on Tobacco Regulation. Report on the scientific basis of tobacco product<br />
regulation: third report of a WHO study group. Geneva: World Health Organization; 2010.<br />
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(e cigarette) on desire to smoke and withdrawal, user preferences and nicotine delivery: randomised cross-over trial.<br />
Tob Control. 2010;19(2):98–103. [PubMed]<br />
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23. Nokingdays. [cited 2011 Jul 10]. Available from http://www.nokingdaysmall.com/<br />
24. Lee S, Yun JE, Lee JK, Kim IS, Jee SH. The Korean prediction model for adolescents' future smoking intentions. J<br />
Prev Med Public Health. 2010;43(4):283–291. [PubMed]<br />
25. Bricker JB, Peterson AV, Robyn Andersen M, Leroux BG, Bharat Rajan K, Sarason IG. Close friends', parents',<br />
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[PubMed]<br />
26. de Vries H, Engels R, Kremers S, Wetzels J, Mudde A. Parents' and friends' smoking status as predictors of<br />
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27. DiFranza JR, Wellman RJ, Mermelstein R, Pbert L, Klein JD, Sargent JD, et al. The natural history and diagnosis of<br />
nicotine addiction. Curr Pediatr Rev. 2011;7(2):88–96.<br />
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cigarettes. Addict Behav. 2008;33(5):689–698. [PubMed]<br />
29. Apollonio DE, Bero LA. The creation of industry front groups: the tobacco industry and "get government off our<br />
back". Am J Public Health. 2007;97(3):419–427. [PMC free article] [PubMed]<br />
30. Morley CP, Cummings KM, Hyland A, Giovino GA, Horan JK. Tobacco Institute lobbying at the state and local<br />
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31. Phiip Morris International (PMI) enters into a patent purchase agreement of new technology with the potential to<br />
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http://www.pmi.com/eng/media_center/press_releases/pages/201105261249.aspx.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
21 Nicotine e-cigarette cartridges can be sold as to-<br />
bacco products.
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Journal of the New Zealand Medical Association, 21-January-2011, Vol 124 No 1328<br />
Nicotine e-cigarette cartridges can be sold as tobacco<br />
products<br />
End Smoking NZ, a charitable trust focussed on tobacco policy, has identified the sale of safer,<br />
satisfying nicotine products as a top priority for greatly reducing smoking. 1 Tobacco smoke<br />
includes thousands of compounds, including carcinogens, and lung and cardiovascular toxicants.<br />
In contrast, pure nicotine carries far less risk, and can provide a safer alternative for those too<br />
addicted to yet quit smoking.<br />
Medsafe’s interpretation of the Medicines Act is that nicotine electronic (e-)cigarettes (which<br />
vapourise nicotine into a mist for inhalation) are medicines “even if they are not represented as<br />
aids to smoking cessation”, 2 and cannot be sold unless medicinally licensed. As no such licensing<br />
is imminent, a virtual ban is in place.<br />
Instead, we argue that nicotine e-cigarettes are primarily recreational nicotine alternatives to<br />
smoking, though some brands may obtain licensing as medicines at some future date. We argue<br />
they already qualify as tobacco products under the Smoke-free Environments (SFE) Act, which<br />
has regulated all tobacco products for (recreational) human consumption since 1990. For<br />
example, at Section 30, the Act bans their sale to those under 18 years of age, while at Section 31<br />
it has powers to reduce or remove any substances deemed hazardous. All that e-cigarette<br />
distributors would have to do, is strictly refrain from making therapeutic claims, and abide by<br />
current or future regulations of the SFE Act. We now examine how the SFE Act can<br />
accommodate nicotine electronic cigarettes.<br />
The SFE Act’s interpretation section defines a tobacco product as:<br />
...“any product manufactured from tobacco and intended for use by smoking, inhalation, or<br />
mastication and includes nasal and oral snuff, but does not include any medicine (being a<br />
medicine in respect of which there is in force a consent or provisional consent under section 20<br />
or section 23 of the Medicines Act 1981) that is sold or supplied wholly or principally for use as<br />
an aid in giving up smoking.”<br />
Thus the nicotine e-cigarette can be classified as a tobacco product, if its nicotine is<br />
manufactured from tobacco (it is) and it is not supplied wholly or principally as an aid in giving<br />
up smoking. 3<br />
Nicotine e-cigarettes, unlike medicinal nicotine patches or gum, are shaped and designed to<br />
provide nicotine-based and smoking-ritual-based pleasure by inhalation, and so can be regarded as<br />
tobacco products provided no medicinal claims are made. A recent United States district court<br />
decision, 4 upheld on appeal in December 2010, supports the classification of e-cigarettes as<br />
inhaled tobacco products, and recognises that almost all nicotine is consumed for recreational, not<br />
medicinal purposes.<br />
According to the definition above, tobacco products can be used for smoking, inhalation or<br />
mastication. Of these three, the SFE Act permits sale for smoking, but not for oral use, and does<br />
not mention sale for inhalation:<br />
...“No person shall import for sale, sell, pack, or distribute any tobacco product labelled or<br />
otherwise described as suitable for chewing, or for any other oral use (other than smoking)”. 5<br />
Sale of nasal tobacco snuff for inhalation remains legal. Sale of nicotine electronic cigarettes for<br />
inhalation is not mentioned; and their import, distribution and sale can we believe, be allowed<br />
under the SFE Act. This is reinforced by observations on how e-cigarettes are used—for<br />
inhalation, not oral use.<br />
As with cigarettes the e-cigarette mist is inhaled, but more negative pressure is needed, 6 requiring<br />
inhalation directly to the lungs. Smokers switching to e-cigarettes, instead of holding smoke in the<br />
mouth before inhalation as many smokers do, learn to inhale mist into the lungs in a one-stage<br />
manoeuvre.
http://journal.nzma.org.nz/journal/124-1328/4521/ 2/2<br />
The mouth has a separate secondary role as part of the respiratory tract, and the inhaled mist<br />
transits the mouth in seconds, whereas oral products (snuff or nicotine gum) are normally held in<br />
the mouth for half an hour. For the above reasons, we believe the sale of electronic cigarettes is<br />
not caught by the Act’s ban on sale of oral tobacco products.<br />
As nicotine e-cigarettes contain no tobacco, they attract no tobacco excise. Nicotine-free<br />
electronic cigarettes are widely advertised and sold, but most users want nicotine cartridges –<br />
which, being tobacco products, cannot be advertised (Section 22, SFE Act). Every nicotine<br />
cartridge sold means a pack of cigarettes not sold. UK surveys have shown 52% of smokers<br />
have heard of e-cigarettes but never tried them, 6% of smokers have tried them but no longer use<br />
them, and 3% currently use them. 7<br />
The Maori Affairs Select Committee Tobacco Inquiry recommended further research into the<br />
benefits and risks of alternative products. 8<br />
A recent review backs e-cigarettes as much safer than cigarettes, although absolute safety is yet<br />
to be proven. 9 Further reliance, however, on regulation solely under the Medicines Act, as at<br />
present, would deny satisfaction to the thousands of smokers who have already bought ecigarettes<br />
without nicotine, as currently advertised. No hospitalisations or deaths have been<br />
reported globally so far from over 3 years of nicotine e-cigarette sales. Smokers merely want the<br />
choice now, without having to order the nicotine cartridges from China.<br />
Conclusion—The Smoke-free Environments Act provides a comprehensive framework for<br />
governing recreational tobacco and nicotine, and already permits the import, distribution, and sale<br />
of nicotine electronic cigarettes as tobacco products.<br />
Murray Laugesen, Marewa Glover, Trish Fraser, Ross McCormick, John Scott<br />
Board Members, End Smoking NZ Trust<br />
chair@endsmoking.org.nz<br />
References:<br />
1. Laugesen M. Glover M, Fraser T, McCormick R, Scott J. Four policies to end the sale of<br />
cigarettes and smoking tobacco in New Zealand by 2020. N Z Med J 14 May<br />
2010;123(1314). http://www.nzma.org.nz/journal/123-1314/4107/<br />
2. Medical devices, Categorisation of electronic cigarettes. Medsafe website, accessed 22<br />
Dec 2010.<br />
http://www.medsafe.govt.nz/regulatory/medicaldevices/electroniccigarettes.asp<br />
3. Laugesen M. Nicotine electronic cigarette sales are permitted under the Smokefree<br />
Environments Act [Letter]. N Z Med J 29 January-2010;123(1308).<br />
http://www.nzmj.com/journal/123-1308/3955/content.pdf<br />
4. Smoking Everywhere Inc and Sottera Inc c/b/a NJoy v. US Food and Drug<br />
Administration et al (defendants). Civil case 09-771 (RJL) Memorandum Opinion Jan 14,<br />
2010. US District Court for the District of Columbia.<br />
5. Smoke-free Environments Act, section 29(2).<br />
http://www.legislation.govt.nz/act/public/1990/0108/latest/DLM224309.html?<br />
search=ts_act_Smoke-free+Environments+Act_resel&p=1<br />
6. Trtchounian A, Williams Williams M, Talbot P. Conventional and electronic cigarettes<br />
(e-cigarettes) have different smoking characteristics, Nicotine Tob Res. 2010<br />
Sep;12(9):905-12. Epub 2010 Jul 19.<br />
7. Dockrell M. What smokers tell us about e-cigarettes. Society for Research on Nicotine<br />
and Tobacco Conference (Europe), Bath, England, 2010.<br />
8. Maori Affairs Committee. Inquiry into the tobacco industry in Aotearoa and the<br />
consequences of tobacco use for Maori. Report. Forty-Ninth Parliament. Hon Tau<br />
Henare, chairperson. Wellington, November 2010. p40.<br />
9. http://www.parliament.nz/NR/rdonlyres/C6AAA494-A706-48C6-8F91-<br />
6CAF5EA7CA51/164754/DBSCH_SCR_4900_InquiryintothetobaccoindustryinAote.pdf<br />
10. Cahn Z, Siegel M. Electronic cigarettes as a harm reduction strategy for tobacco<br />
control: A step forward or a repeat of past mistakes? J Public Health Policy. 2010;9 Dec:<br />
doi:10.1057/jphp.2010.41,1-16.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
22 Electronic cigarettes and thirdhand tobacco<br />
smoke two emerging health care challenges for<br />
the primary care provider.
http://www.ncbi.nlm.nih.gov/pubmed/21475626 1/2<br />
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Int J Gen Med. 2011 Feb 1;4:115-20. doi: 10.2147/IJGM.S16908.<br />
Electronic cigarettes and thirdhand tobacco smoke: two emerging health<br />
care challenges for the primary care provider.<br />
Kuschner WG, Reddy S, Mehrotra N, Paintal HS.<br />
Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Palo Alto, CA, USA.<br />
Abstract<br />
PRIMARY CARE PROVIDERS SHOULD BE AWARE OF TWO NEW DEVELOPMENTS IN<br />
NICOTINE ADDICTION AND SMOKING CESSATION: 1) the emergence of a novel nicotine delivery<br />
system known as the electronic (e-) cigarette; and 2) new reports of residual environmental nicotine<br />
and other biopersistent toxicants found in cigarette smoke, recently described as "thirdhand<br />
smoke". The purpose of this article is to provide a clinician-friendly introduction to these two<br />
emerging issues so that clinicians are well prepared to counsel smokers about newly recognized<br />
health concerns relevant to tobacco use. E-cigarettes are battery powered devices that convert<br />
nicotine into a vapor that can be inhaled. The World Health Organization has termed these devices<br />
electronic nicotine delivery systems (ENDS). The vapors from ENDS are complex mixtures of<br />
chemicals, not pure nicotine. It is unknown whether inhalation of the complex mixture of chemicals<br />
found in ENDS vapors is safe. There is no evidence that e-cigarettes are effective treatment for<br />
nicotine addiction. ENDS are not approved as smoking cessation devices. Primary care givers<br />
should anticipate being questioned by patients about the advisability of using e-cigarettes as a<br />
smoking cessation device. The term thirdhand smoke first appeared in the medical literature in 2009<br />
when investigators introduced the term to describe residual tobacco smoke contamination that<br />
remains after the cigarette is extinguished. Thirdhand smoke is a hazardous exposure resulting<br />
from cigarette smoke residue that accumulates in cars, homes, and other indoor spaces. Tobaccoderived<br />
toxicants can react to form potent cancer causing compounds. Exposure to thirdhand<br />
smoke can occur through the skin, by breathing, and by ingestion long after smoke has cleared<br />
from a room. Counseling patients about the hazards of thirdhand smoke may provide additional<br />
motivation to quit smoking.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
23 FDA Electronic cigarettes may be risky.
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24 Mining data on usage of electronic nicotine de-<br />
livery systems (ENDS) from YouTube videos
http://tobaccocontrol.bmj.com/content/early/2011/11/24/tobaccocontrol-2011-050226.short 1/2<br />
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Home > Online First > Article<br />
Tob Control doi:10.1136/tobaccocontrol-2011-050226<br />
Research paper<br />
Mining data on usage of electronic nicotine delivery<br />
systems (ENDS) from YouTube videos<br />
My Hua, Henry Yip, Prue Talbot<br />
+<br />
Author Affiliations<br />
Correspondence to<br />
Dr Prue Talbot, Department of Cell Biology & Neuroscience, University of California, Riverside,<br />
CA 92521, USA; talbot@ucr.edu<br />
Contributors PT and MH conceived of the project. MH and HY were involved in data collection<br />
and interpretation. PT and MH performed data analysis and writing of the manuscript.<br />
Received 14 January 2011<br />
Accepted 10 October 2011<br />
Published Online First 24 November 2011<br />
Abstract<br />
Objective The objective was to analyse and compare puff and exhalation duration for<br />
individuals using electronic nicotine delivery systems (ENDS) and conventional cigarettes in<br />
YouTube videos.<br />
Methods Video data from YouTube videos were analysed to quantify puff duration and<br />
exhalation duration during use of conventional tobacco-containing cigarettes and ENDS. For<br />
ENDS, comparisons were also made between ‘advertisers’ and ‘non-advertisers’, genders,<br />
brands of ENDS, and models of ENDS within one brand.<br />
Results Puff duration (mean =2.4 s) for conventional smokers in YouTube videos (N=9)<br />
agreed well with prior publications. Puff duration was significantly longer for ENDS users<br />
(mean =4.3 s) (N = 64) than for conventional cigarette users, and puff duration varied<br />
significantly among ENDS brands. For ENDS users, puff duration and exhalation duration<br />
were not significantly affected by ‘advertiser’ status, gender or variation in models within a<br />
brand. Men outnumbered women by about 5:1, and most users were between 19 and 35<br />
years of age.<br />
Conclusions YouTube videos provide a valuable resource for studying ENDS usage. Longer<br />
puff duration may help ENDS users compensate for the apparently poor delivery of nicotine<br />
from ENDS. As with conventional cigarette smoking, ENDS users showed a large variation in<br />
puff duration (range =1.9–8.3 s). ENDS puff duration should be considered when designing<br />
laboratory and clinical trials and in developing a standard protocol for evaluating ENDS<br />
performance.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
25 Electronic cigarettes e-cigs views of aficionados<br />
and clinical public health perspectives
http://www.ncbi.nlm.nih.gov/pubmed/21801287 1/2<br />
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Int J Clin Pract. 2011 Oct;65(10):1037-42. doi: 10.1111/j.1742-1241.2011.02751.x. Epub 2011 Aug 1.<br />
Electronic cigarettes (e-cigs): views of aficionados and clinical/public health<br />
perspectives.<br />
Foulds J, Veldheer S, Berg A.<br />
Pennsylvania State University, College of Medicine, Hershey, PA 17033-0850, USA. jfoulds@psu.edu<br />
Abstract<br />
Related citations in<br />
BACKGROUND: Electronic cigarettes (e-cigs) have experienced a rapid growth in popularity but PubMed<br />
little is known about how they are used.<br />
Effect of an electronic nicotine<br />
AIM: The aim of this study was to identify the e-cig products used by experienced e-cig users, their<br />
delivery [BMC device Public (e-Cigarette) Health. 2011] on<br />
pattern of e-cig use and the impact on tobacco use.<br />
Interviews with "vapers":<br />
METHOD: Face-to-face survey of 104 experienced e-cig users.<br />
implications [Nicotine for future Tob research Res. 2011]<br />
RESULTS: Of all the e-cig users, 78% had not used any tobacco in the prior 30 days. They had<br />
Electronic cigarette: users<br />
profile, utilization, [Addiction. satisfaction 2011]<br />
previously smoked an average of 25 cigarettes per day, and had tried to quit smoking an average of<br />
nine times before they started using e-cigs. Two-thirds had previously tried to quit smoking using an<br />
FDA-approved smoking cessation medication. The majority of the sample had used e-cigs daily for<br />
Review The emerging<br />
phenomenon [Expert Rev of Respir electronic Med. 2012]<br />
at least a year. Three quarters started using e-cigs with the intention of quitting smoking and almost Review Interventions to reduce<br />
all felt that the e-cig had helped them to succeed in quitting smoking. Two-thirds used e-cig liquid [Cochrane harm from Database continued Syst tobacco Rev. 2007]<br />
with a medium to high concentration of nicotine (13 mg +). Only 8% were using the most widely<br />
See reviews...<br />
sold types of cigarette-sized e-cigs that are typically powered by a single 3.7 volt battery. Instead<br />
most used e-cigs designed to enable the atomizer to more consistently achieve a hotter more<br />
intense vapour.<br />
See all...<br />
CONCLUSION: Until we have more evidence on the safety and efficacy of e-cigs for smoking<br />
cessation, smokers should be advised to use proven treatments (e.g. counselling and FDAapproved<br />
medicines). However, for those who have successfully switched to e-cigs, the priority<br />
should be staying off cigarettes, rather than quitting e-cigs.<br />
© 2011 Blackwell Publishing Ltd.<br />
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Display Settings: Abstract Send to:<br />
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Electronic cigarettes: new kit on the rack. [Int J Clin Pract. 2012]<br />
PMID: 21801287 [PubMed - indexed for MEDLINE]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
26 Electronic nicotine delivery systems a research<br />
agenda
http://tobaccocontrol.bmj.com/content/20/3/243 1/3<br />
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Home > Volume 20, Issue 3 > Article<br />
Tob Control 2011;20:243-248 doi:10.1136/tc.2010.042168<br />
Commentary<br />
Electronic nicotine delivery systems: a research<br />
agenda<br />
Jean-François Etter 1 , Chris Bullen 2 , Andreas D Flouris 3 , Murray Laugesen 4 ,<br />
Thomas Eissenberg 5<br />
+<br />
Author Affiliations<br />
Correspondence to<br />
Jean-François Etter, Institute of social and preventive medicine, University of Geneva, CMU,<br />
case postale, CH-1211 Geneva 4, Switzerland; jean-francois.etter@unige.ch<br />
Contributors All authors participated in the conception and redaction of this paper.<br />
Competing interests CB's salary is paid by The University of Auckland and his research is<br />
supported by grants from the New Zealand Health Research Council (HRC), the University of<br />
Auckland and the NZ Heart Foundation. He has previously undertaken tobacco control<br />
research supported by the New Zealand Ministry of Health, and by Niconovum, Sweden, prior<br />
to the purchase of this company by RJ Reynolds. He is currently an investigator on a study<br />
involving reduced nicotine cigarettes in which the products were purchased by the University<br />
of Auckland from Vector Group Ltd, US. He has previously undertaken research on ENDS<br />
funded by HealthNZ, in which the study products were supplied by Ruyan, Hong Kong; and<br />
he is the principal investigator on an HRC-funded efficacy trial of ENDS that will use products<br />
provided by a NZ-based ENDS retailer. Other than these relationships, he has no conflicts of<br />
interest to declare. TE's salary is paid by Virginia Commonwealth University and his<br />
research is supported by grants from the US National Institutes of Health (R01CA103827<br />
and R01CA120142). In the past he has served as a paid consultant to the National<br />
Association of Attorneys General regarding litigation against a tobacco company. He has<br />
served as an expert consultant for the World Health Organization regarding ENDS. Also, he<br />
has been retained by the US FDA as a consultant but, as of this writing, has not served in<br />
this capacity in any way and has received no payment from the FDA. Other than these<br />
relationships, he has no conflicts of interest to declare. J-FE's salary is paid by the University<br />
of Geneva. He has served as an unpaid expert consultant for the World Health Organization<br />
regarding ENDS, and as a paid consultant for Pfizer, a manufacturer of smoking cessation<br />
medications, in 2006–2007 (on the Swiss varenicline advisory board). The University of<br />
Geneva received trial medications from Pfizer in 2006 for a study conducted by J-FE. No<br />
competing interest since then. AF has no competing interests to declare. ML has researched<br />
various nicotine products including ENDS for several firms and universities, and advised<br />
several distributors, but has no financial interest in any of these.<br />
Abstract<br />
Electronic nicotine delivery systems (ENDS, also called electronic cigarettes or e-cigarettes)<br />
are marketed to deliver nicotine and sometimes other substances by inhalation. Some<br />
tobacco smokers report that they used ENDS as a smoking cessation aid. Whether sold as<br />
tobacco products or drug delivery devices, these products need to be regulated, and thus far,<br />
across countries and states, there has been a wide range of regulatory responses ranging<br />
from no regulation to complete bans. The empirical basis for these regulatory decisions is<br />
uncertain, and more research on ENDS must be conducted in order to ensure that the<br />
decisions of regulators, health care providers and consumers are based on science.<br />
However, there is a dearth of scientific research on these products, including safety, abuse<br />
liability and efficacy for smoking cessation. The authors, who cover a broad range of scientific<br />
expertise, from basic science to public health, suggest research priorities for non-clinical,<br />
clinical and public health studies. They conclude that the first priority is to characterize the<br />
safety profile of these products, including in long-term users. If these products are<br />
demonstrated to be safe, their efficacy as smoking cessation aids should then be tested in<br />
appropriately designed trials. Until these studies are conducted, continued marketing<br />
constitutes an uncontrolled experiment and the primary outcome measure, poorly assessed,<br />
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is user health. Potentially, this research effort, contributing to the safety and efficacy of new<br />
smoking cessation devices and to the withdrawal of dangerous products, could save many<br />
lives.<br />
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ENDS (E-cigarettes): No Such Research Needed<br />
Joel L Nitzkin<br />
Tob Control published online July 13, 2011<br />
[Full text]<br />
E-cigarettes are not just another NRT<br />
Elaine D Keller<br />
Tob Control published online July 13, 2011<br />
[Full text]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
27 Electronic cigarette users profile, utilization, sat-<br />
isfaction and perceived efficacy.
http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03505.x/abstract 1/2<br />
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Electronic cigarette: users profile, utilization, satisfaction and perceived<br />
efficacy<br />
Jean-François Etter 1,* , Chris Bullen 2<br />
Article first published online: 27 JUL 2011<br />
DOI: 10.1111/j.1360-0443.2011.03505.x<br />
© 2011 The Authors, Addiction © 2011 Society for<br />
the Study of Addiction<br />
Additional Information (Show All)<br />
Abstract Article References Cited By<br />
Keywords:<br />
E-cigarette; electronic cigarette; electronic nicotine delivery systems (ENDS); internet; nicotine; smoking; tobacco use disorder<br />
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Addiction<br />
Volume 106, Issue 11, pages<br />
2017–2028, November 2011<br />
Conference presentation: This study was presented at the European Conference on Tobacco or<br />
Health, Amsterdam, the Netherlands, 28–30 March 2011.<br />
Jean-François Etter Chris Bullen All Authors<br />
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ABSTRACT<br />
Aims To assess the profile, utilization patterns, satisfaction and perceived effects among users of electronic cigarettes (‘e-cigarettes’).<br />
Design and Setting Internet survey in English and French in 2010.<br />
Measurements Online questionnaire.<br />
Participants Visitors of websites and online discussion forums dedicated to e-cigarettes and to smoking cessation.<br />
Findings There were 3587 participants (70% former tobacco smokers, 61% men, mean age 41 years). The median duration of electronic<br />
cigarette use was 3 months, users drew 120 puffs/day and used five refills/day. Almost all (97%) used e-cigarettes containing nicotine.<br />
Daily users spent $33 per month on these products. Most (96%) said the e-cigarette helped them to quit smoking or reduce their smoking<br />
(92%). Reasons for using the e-cigarette included the perception that it was less toxic than tobacco (84%), to deal with craving for tobacco<br />
(79%) and withdrawal symptoms (67%), to quit smoking or avoid relapsing (77%), because it was cheaper than smoking (57%) and to<br />
deal with situations where smoking was prohibited (39%). Most ex-smokers (79%) feared they might relapse to smoking if they stopped<br />
using the e-cigarette. Users of nicotine-containing e-cigarettes reported better relief of withdrawal and a greater effect on smoking<br />
cessation than those using non-nicotine e-cigarettes.<br />
Conclusions E-cigarettes were used much as people would use nicotine replacement medications: by former smokers to avoid relapse<br />
or as an aid to cut down or quit smoking. Further research should evaluate the safety and efficacy of e-cigarettes for administration of<br />
nicotine and other substances, and for quitting and relapse prevention.<br />
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28 Electronic cigarettes a survey of users.
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BMC Public Health 2010, 10:231 doi:10.1186/1471-2458-10-231<br />
The electronic version of this article is the complete one and can be found online at:<br />
http://w w w.biomedcentral.com/1471-2458/10/231<br />
Received: 27 October 2009<br />
Accepted: 4 May 2010<br />
Published: 4 May 2010<br />
© 2010 Etter; licensee BioMed Central Ltd.<br />
This is an Open Access article distributed under the terms of the Creative Commons Attribution License<br />
Abstract<br />
Background<br />
Little is know n about users of electronic cigarettes, or their opinions, satisfaction or how and w hy they use such<br />
products.<br />
Methods<br />
An internet survey of 81 ever-users of ecigarettes in 2009. Participants answ ered open-ended questions on use of,<br />
and opinions about, ecigarettes.<br />
Results<br />
Respondents (73 current and 8 former users) lived in France, Canada, Belgium or Sw itzerland. Most respondents<br />
(77%) w ere men; 63% w ere former smokers and 37% w ere current smokers. They had used e-cigarettes for 100<br />
days (median) and drew 175 puffs per day (median). Participants used the ecigarette either to quit smoking (53<br />
comments), to reduce their cigarette consumption (14 comments), in order not to disturb other people w ith smoke (20<br />
comments), or in smoke-free places (21 comments). Positive effects reported w ith ecigarettes included their<br />
usefulness to quit smoking, and the benefits of abstinence from smoking (less coughing, improved breathing, better<br />
physical fitness). Respondents also enjoyed the flavour of ecigarettes and the sensation of inhalation. Side effects<br />
included dryness of the mouth and throat. Respondents complained about the frequent technical failures of<br />
ecigarettes and had some concerns about the possible toxicity of the devices and about their future legal status.<br />
Conclusions<br />
Ecigarettes w ere used mainly to quit smoking, and may be helpful for this purpose, but several respondents w ere<br />
concerned about potential toxicity. There are very few published studies on ecigarettes and research is urgently<br />
required, particularly on the efficacy and toxicity of these devices.<br />
Background<br />
In recent years several manufacturers, mainly in China, have produced electronic cigarettes (ecigarettes) that are<br />
distributed in w estern countries, often by small, new ly established companies [1-4]. Electronic cigarettes look and feel<br />
like cigarettes, but do not burn tobacco. The several existing brands vary but, in general, ecigarettes contain a battery<br />
and an electronic device that produces a w arm vapour or 'mist'. The vapour usually contains nicotine and often - but<br />
not alw ays - contains propylene glycol [5]. The vapour is inhaled and, as the user exhales, some visible vapour is<br />
released, but no tobacco smoke. Some ecigarettes also contain a light-emitting diode in the tip that glow s w hen the<br />
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user puffs, to resemble the burning end of a cigarette. The nicotine content of the cartridge varies, and the cartridges<br />
usually contain chemical additives and flavours (such as various brands of tobacco, chocolate, coffee, mint or fruit).<br />
The cartridges can usually be refilled, and refill bottles are provided w ith the device.<br />
Electronic cigarettes are probably less harmful than tobacco smoking, but they are almost certainly more dangerous<br />
than medicinal nicotine inhalers [6,7]. How ever, to our know ledge, there is no published data on the safety of<br />
ecigarettes. Internationally, the legality of ecigarettes varies; they cannot be sold in Australia, Brazil, Canada, Denmark<br />
or Sw itzerland, but their sale is authorized in other countries (e.g. China, New Zealand) [5,8,9]. Analyses conducted<br />
by the United States Food and Drug Administration (FDA) show ed that ecigarettes contain carcinogens, including<br />
nitrosamines, toxic chemicals such as diethylene glycol, and tobacco-specific components suspected of being<br />
harmful to humans (anabasine, myosmine, and beta-nicotyrine) [6]. The FDA also found that ecigarette cartridges<br />
labelled as containing no nicotine did in fact contain low levels of nicotine. Some manufacturers do not disclose the<br />
ingredients in their products. Furthermore, ecigarettes are not manufactured according to the high standards imposed<br />
on pharmaceutical companies. Consequently, the inhaled vapour may contain impurities that may be dangerous to<br />
consumers [6]. In particular, the origin of the nicotine itself is uncertain, as pesticide-grade nicotine rather than<br />
pharmacological-grade nicotine may be used in ecigarettes.<br />
Little is know n about ecigarettes, as few research reports have been published [10,11]. In addition to the FDA report<br />
mentioned above, reports from New Zealand, funded by Ruyan (a Chinese manufacturer of ecigarettes) concluded<br />
that the mist from the Ruyan ecigarette contains acetaldehyde and mercury [12,13]. A randomised trial in 40 smokers<br />
found that the Ruyan ecigarette delivered nicotine to the blood more rapidly than the nicotine inhaler, but less rapidly<br />
than cigarettes, and that the effect of the ecigarette on craving w as similar to that of the nicotine inhaler, but less than<br />
that of cigarettes [14]. A recent U.S. study found that 10 puffs of an ecigarette delivered little or no nicotine [15].<br />
The mist from ecigarettes is inhaled into the lung [13]. Although the particle size is apparently too small to ensure<br />
deposition in the lung alveoli [12], w e are not aw are of any study of lung absorption of ecigarette mist. Because lung<br />
inhalation may enable nicotine to pass rapidly into the blood, and thus rapidly relieve craving and tobacco w ithdraw al<br />
symptoms [14], ecigarettes have the potential to be at least as effective as currently approved nicotine replacement<br />
therapy (NRT) products, none of w hich deliver nicotine to the lung. In addition, the similarities in shape, actions and<br />
inhalation betw een ecigarettes and tobacco cigarettes could also help smokers quit. How ever, as there are no data to<br />
support the manufacturers' claims that ecigarettes help smokers quit, the World Health Organization asked the<br />
companies not to make any therapeutic claims [7,16]. If they claimed that ecigarettes help smokers quit, manufacturers<br />
w ould be subject to the legislation and regulation that applies to NRT products. In order to avoid this, some ecigarettes<br />
are now marketed for enjoyment, or as devices that enable smokers to "smoke" everyw here, including smoke-free<br />
places [3,4]. Nonetheless, some distributors present their products as an alternative to tobacco smoking, more or less<br />
implicitly suggesting that ecigarettes can be used to aid smoking cessation [1,2].<br />
One may hypothesize that the positive effects of ecigarettes may include smoking cessation, smoking reduction or<br />
relapse prevention. The ecigarette could also be used as an aid during a preparation period before cessation, similar<br />
to the pre-cessation treatment or "cut dow n to quit" approach that is an approved indication for NRT [17]. On the other<br />
hand, ecigarettes may be dangerous because of the frequent and longterm lung inhalation of diethylene glycol,<br />
nicotine and other toxic components, and because of the sub-standard manufacturing process, relative to<br />
pharmaceutical products [7]. Because of its rapid nicotine delivery [14], the ecigarette also has the potential to be<br />
addictive. In addition, the refill bottles may be dangerous as they contain up to one gram of nicotine, w hereas the fatal<br />
dose of nicotine is estimated to be 30 to 60 mg for adults and 10 mg for children [5]. The ecigarette may also enable<br />
smokers to continue to 'smoke' in smoke-free environments, thus delaying or preventing cessation in people w ho<br />
might otherw ise quit. Finally, the fruit and chocolate flavours may appeal to young people, and this raises the concern<br />
that ecigarettes may facilitate initiation of nicotine dependence in young never-smokers [5]. How ever, none of these<br />
hypotheses has yet been tested.<br />
Because of the huge burden of tobacco-related death and disease, and because ecigarettes have potential to help<br />
smokers quit, there is an urgent need for research into these products. First, there is a need to know w hy and how<br />
these products are used, and w hether users are satisfied w ith them. The aim of this study w as to assess usage<br />
patterns of ecigarettes, reasons for use, and users' opinions of these products.<br />
Methods<br />
As ecigarettes are mainly sold online, the internet is a logical w ay to reach users. We therefore posted a survey<br />
form, in French, on the smoking cessation w ebsite StopTabac.ch over a 34 day period betw een September and<br />
October 2009. This w ebsite receives approximately 120,000 visitors per month and is principally visited either by<br />
smokers w ho intend to quit or by recent quitters [18,19]. Links to the survey w ere posted on w ebsites that either<br />
provide information about ecigarettes (ecigmag.com, forumecigarette.com) or sell them (econoclope.com,<br />
sedansa.be). After discussion w ith the head of the ethics committee of the Geneva University Hospitals (community<br />
medicine section, the committee to w hich our Institute is submitted), the study w as exempted from approval.<br />
Eligible participants w ere people w ho declared that they had ever used an ecigarette and w ho provided the brand<br />
name of the ecigarette that they had used most often. Subjects w ho did not name a brand w ere excluded, because<br />
this raised doubts about w hether they had actually used an ecigarette. On the survey form, participants indicated<br />
w hether they had ever used ecigarettes or w ere currently using them (subdivided into daily user, non-daily user,<br />
former user, never used). They also provided the total number of days that they had been using ecigarettes, the<br />
brand they used most often, the nicotine dose per unit, the flavour and the cost per package (using open-ended<br />
questions). In addition, subjects indicated w hether ecigarettes had helped them to quit smoking, and current users<br />
indicated the number of puffs per day on ecigarettes.<br />
In response to open-ended questions, participants w rote w here they bought their ecigarettes, the reasons w hy they<br />
used them, w hat they considered to be the beneficial and undesirable effects of ecigarettes, and the most positive<br />
and negative points about the product. If they had stopped using ecigarettes, they explained w hy. Participants also<br />
listed w hich questions they had asked themselves about ecigarettes, and gave their opinion on the information<br />
leaflets or documents inserted in the ecigarette packages. Finally, they w rote general comments on the ecigarette.<br />
Other questions also covered smoking status (daily, non-daily, former smoker, never smoker). Smokers stated the<br />
number of cigarettes they smoked per day, and former smokers stated w hen they had quit smoking. Participants w ere
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asked to supply their age, sex and country of residence.<br />
Medians rather than means w ere used for continuous variables because medians are less sensitive to outliers,<br />
w hich can excessively influence means in small sample sizes.<br />
Results<br />
Answ ers w ere obtained from 214 people, but 123 of these had never used ecigarettes and ten did not name the<br />
brand of their ecigarette. These 133 subjects w ere excluded. All subsequent analyses included only the 81<br />
respondents w ho declared that they had ever used ecigarettes and w ho indicated the brand that they had used most<br />
often. These 81 respondents included 72 daily users of ecigarettes, one non-daily user and eight former users (Table<br />
1). They w ere relatively young (median age 37 years), and most (77%) w ere men. Respondents lived in France<br />
(81%), Belgium (8%), Canada (6%) and Sw itzerland (5%). Most (63%) w ere former smokers w ho had quit smoking<br />
relatively recently (median duration of abstinence: 100 days) (Table 1).<br />
Table 1. Characteristics of ecigarette users, and usage patterns<br />
Use of the electronic cigarette<br />
Most respondents had been using the ecigarette for slightly longer than three months, and current users took 175<br />
puffs per day (median) from their device (Table 1). Sixteen different brands of ecigarettes w ere named, the most<br />
frequent being Janty (n = 17), Joye (n = 17), Sedansa (n = 14), Econoclope (n = 9), Liberty-cig (n = 8), Smoke51 and<br />
Edsylver (n = 2 each). All these brands of ecigarette deliver nicotine, and the median dose of nicotine per unit w as 14<br />
mg. The preferred flavour (open-ended field, 78 answ ers) w as tobacco (n = 46, various flavours, e.g. "Turkish<br />
blend", "K-mel"), follow ed by mint (n = 6), fruit (n = 5, e.g. "apple"), vanilla (n = 4), coffee (n = 3) and tea (n = 2).<br />
Tw elve respondents used several of these flavours.<br />
Most respondents (n = 74; 94% of 79 answ ers) had bought their ecigarette on the internet, tw o had bought their<br />
device in China, tw o at a tobacco retail shop and one had bought it second hand. When asked w hether the ecigarette<br />
helped them quit smoking, most respondents (79%) answ ered "a lot" (Table 1).<br />
When asked w hy they chose to use ecigarettes (three open-ended fields, 225 comments), the most frequent<br />
answ ers w ere: that they used it to quit smoking; for their health (as ecigarettes w ere perceived to be less toxic than<br />
tobacco, e.g.: "it is better for health than tobacco"); because ecigarettes are less expensive than regular cigarettes;<br />
because ecigarettes can be smoked everyw here, including smoke-free places (e.g.: "I don't need to go outside to<br />
smoke anymore"); to avoid disturbing other people w ith second-hand smoke; for the pleasure of smoking it (e.g.: "to<br />
continue to inhale, w hich is something I like"), and to reduce their cigarette consumption (Table 2).<br />
Table 2. Reasons for using e-cigarettes: open-ended comments from e-cigarette users<br />
The most frequently cited beneficial effects of ecigarettes (tw o open-ended fields, 134 comments) w ere: that it<br />
improved breathing and respiration (e.g.: "I have less breathlessness on exertion"); that it helps to quit smoking (e.g.:<br />
"I have quit smoking w ithout problems"); that respondents coughed less, expectorated less and had few er sore<br />
throats; that it improved their health and physical fitness; and that it did not cause unpleasant odours or bad breath<br />
(Table 3). Interestingly, one respondent suggested that the ecigarette device might be useful to administer other<br />
medications to the bronchia or lung. The tw o open-ended fields on the undesirable effects of ecigarettes elicited 61<br />
comments (only half the number of comments received on the beneficial effects). The most frequent responses w ere<br />
that ecigarettes caused dry mouth and throat, vertigo, headache or nausea (Table 3).<br />
Table 3. Beneficial and undesirable effects of e-cigarettes: open-ended comments from ecigarette users<br />
The most frequently cited positive features of ecigarettes (three open-ended fields, 208 comments) w ere: that<br />
respondents liked the taste and variety of flavours; they appreciated the beneficial effects of the ecigarette on their<br />
health, breathing and cough; the absence of unpleasant odours or bad breath; they appreciated the pleasure of<br />
inhalation, and harsh sensation in the throat; they liked the act of using the ecigarette, w hich is similar to smoking; the<br />
ecigarette is less toxic than tobacco smoke; it facilitates smoking cessation; and that it can be used everyw here<br />
(Table 4).<br />
Table 4. The most positive and negative aspects of ecigarettes: open-ended comments from e-cigarette users<br />
When asked about the three most negative aspects of ecigarettes (three fields, 154 comments), respondents<br />
complained in particular about the poor quality of the devices. They also reported that that ecigarettes w ere difficult or<br />
impractical to use (e.g. "it is difficult to refill the liquid"), that the dosage w as difficult to adjust (either too high or too<br />
low ), that the liquid can leak out during use, and complained about the lack of information on the composition of the<br />
vapour and any health risks associated w ith ecigarettes (Table 4).<br />
Respondents also stated w hich questions they had asked themselves about ecigarettes (three fields, 112 comments).<br />
This section show ed that users w ondered w hether ecigarettes w ere safe, w hat the effects on health w ere, and<br />
w hether ecigarettes are toxic (59 comments, including five that specifically mentioned propylene glycol).<br />
Respondents w ere also concerned that the e-cigarette might be banned, and about its future legal status (19<br />
comments, e.g.: "let's hope it w ill not be prohibited"). They w anted to know about the composition of the liquid in the<br />
cartridge (10 comments, e.g.: "What exactly is the content of this liquid?", including four comments on the quality of<br />
the liquids), w hy no serious studies on ecigarettes have been published (5 comments), w hy ecigarettes are not sold<br />
in pharmacies (4 comments) and w hy the devices are not produced in w estern countries (3 comments).<br />
When asked to comment on the documentation that accompanied their ecigarette (one field, 70 comments), most<br />
respondents answ ered that the inserts w ere good or satisfactory (31 comments), seven responded that they w ere<br />
only adequate, 15 responded that they contained too little information, four reported that there w as no explanatory<br />
leaflet w ith their ecigarette, and tw o complained that there w as no explanation of the health effects of ecigarettes.<br />
Three people responded that they used the internet and online discussion forums to obtain more information on<br />
ecigarettes (e.g.: "the insert w as very brief, but fortunately, there are specialized internet discussion forums").<br />
The section that asked participants to w rite general comments on the ecigarette (one field) elicited 64 comments.
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Tw enty-one comments w ere very positive or enthusiastic (e.g. "brilliant" (6 times), "miracle product", "unbelievable",<br />
"very satisfied"), and 11 w ere positive but more neutral (e.g.: "good", "I recommend it"). Respondents also considered<br />
that the ecigarette helped them quit smoking (14 comments), that it w as more effective than either nicotine patch or<br />
bupropion (5 comments), and that it enabled them to reduce their cigarette consumption (3 comments). Three people<br />
feared that the ecigarette w ould soon be banned. Four commented that ecigarettes need technical improvement, and<br />
six w rote negative comments (e.g.: "not helpful to quit", "avoid it").<br />
Eight respondents had stopped using ecigarettes, and w ere asked to indicate w hy (tw o fields, 15 comments).<br />
Reasons included: it did not help me quit smoking (6 comments); it did not taste like cigarettes (3 comments); poor<br />
quality or not reliable (3 comments); because of concerns about risks and side-effects of ecigarettes (3 comments).<br />
Interestingly, several respondents used a neologism (vapoter , in French) to describe the action of smoking an<br />
ecigarette; this term probably originated from "vapour" and spread in online discussion forums. The corresponding<br />
terms used on English-language forums (e.g. ecigarette-forum.com) are "vaping" and "vaper".<br />
Discussion<br />
Although, for legal reasons, ecigarettes are mainly marketed to current smokers either for enjoyment or for use in<br />
smoke-free places, our results suggest that most people w ho buy these products are current and former smokers<br />
w ho use ecigarettes to help quit smoking, just as they w ould use NRT. Our survey also show ed that ecigarettes<br />
w ere liked by users, and w ere used quite intensively by this sample; almost all respondents w ere daily ecigarette<br />
users, and the number puffs per day (175) w as substantial. How ever, as ecigarettes deliver about one-tenth of the<br />
nicotine per puff compared to cigarettes [12], this intensive puffing pattern may result in less exposure to nicotine<br />
than smoking. Interestingly, the median duration of ecigarette use corresponded to the median duration of abstinence<br />
in former smokers (100 days in both cases).<br />
Respondents reported more positive than negative effects w ith ecigarettes: many reported positive effects on the<br />
respiratory system (breathing better, coughing less), w hich w ere probably associated w ith stopping smoking [20].<br />
The fact that ecigarettes do not produce any unpleasant odours or environmental tobacco smoke w as also<br />
appreciated. Most importantly, many respondents reported that the ecigarette helped them quit smoking, and several<br />
compared it favourably w ith either nicotine patch or bupropion. These preliminary findings, together w ith data<br />
show ing that ecigarettes relieve craving and w ithdraw al [14], suggest that the ecigarette may be an effective aid to<br />
smoking cessation, and therefore merits serious investigation for this purpose. Ideally, future trials should compare<br />
the efficacy of ecigarettes versus NRT (particularly the nicotine inhaler), bupropion or varenicline. How ever, as<br />
ecigarettes are probably more toxic than NRT products [6], the former should probably only be recommended to<br />
smokers if they are substantially more effective than current NRTs, and if the toxic constituents of ecigarettes can be<br />
eliminated.<br />
Interestingly, dry mouth and throat w as a frequent adverse effect of the ecigarette. It may be useful to investigate<br />
w hy this occurs and how it might be minimised. It w ould also be interesting to investigate w hy ecigarettes appeal<br />
more to men than to w omen. Many respondents complained of the poor quality of ecigarettes, their frequent failures,<br />
the lack of durability of cartridges and batteries, and that the liquid sometimes leaks from the device during usage.<br />
Apparently competition betw een manufacturers has not yet resulted in products of sufficient technical quality.<br />
Although users' comments w ere generally positive, many w ere concerned about the safety and toxicity of<br />
ecigarettes, and questioned w hy no study has yet investigated these aspects. Several respondents w ere also<br />
concerned about the future legal status of ecigarettes, and that they may possibly be banned. Indeed, health<br />
authorities in several countries have published w arnings about, or have prohibited the sale of, ecigarettes [5-8]. From<br />
a public health perspective, how ever, the question is w hether - at a population level - the potential benefits of the<br />
ecigarette outw eigh its draw backs. If ecigarettes are more effective than current NRTs, but are w ithdraw n from the<br />
market until approved as smoking cessation aids, ecigarette users might revert to smoking tobacco, w hich is more<br />
hazardous than ecigarettes. This could have a significant, negative impact on public health, because it can take<br />
several years to obtain legal approval for a new drug delivery system.<br />
On the other hand, ecigarettes are not currently manufactured to the same rigorous standards as pharmaceutical<br />
products; they currently contain toxic components and are therefore almost certainly less safe than NRT products [6].<br />
The legal status of the e-cigarette is unclear in many countries, and its regulation is complex; it is neither classed as a<br />
tobacco product, nor food, nor is it registered as a medicine. From the legal perspective, there is a difficult balance<br />
betw een the need to protect consumers and the possibility now being offered to smokers to use a new, acceptable<br />
and potentially effective device to stop smoking. Given the enormous burden of disease and death caused by<br />
tobacco smoking, there is an urgent need for research into the toxicity, efficacy and public health impact of<br />
ecigarettes [10]. In addition, w hether devices that resemble ecigarettes could be used to deliver medications other<br />
than nicotine to the lung and bronchia also w arrants investigation. As the manufacturers and distributors of<br />
ecigarettes are relatively small companies that may be unable to afford the research costs, or possess the expertise<br />
or manpow er to go through the regulatory approval process, support from governments, public health organizations<br />
or foundations may be needed to produce evidence on these novel devices.<br />
One limitation of our study is that it w as conducted in a self-selected sample of internet users. Whether this method<br />
over-sampled satisfied users, long-term users or heavy users of ecigarettes is unknow n. Compared to population-<br />
based samples of smokers in Europe or the United States, visitors to the Stop-Tabac.ch w ebsite are more likely to<br />
have made a quit attempt in the previous year, are more motivated to quit smoking, are slightly less dependent on<br />
tobacco, and are more highly educated [18,19]. Thus, although our results provide useful and interesting preliminary<br />
information on ecigarette users, our findings may not be generalizable and should be interpreted w ith caution.<br />
Conclusions<br />
Our results suggest that ecigarettes are used mainly to quit smoking, and may be useful for this purpose. How ever,<br />
users w ere concerned about the potential toxicity of these devices. Very few studies have investigated ecigarettes<br />
and research is now urgently required, particularly to establish the efficacy and toxicity of these devices.<br />
Competing interests
http://www.biomedcentral.com/1471-2458/10/231 5/6<br />
The Institute of Social and Preventive Medicine of the University of Geneva received trial medications in 2005 from<br />
Pfizer, and the author consulted for Pfizer, a manufacturer of smoking cessation medications, in 2006-2007 (on the<br />
Sw iss varenicline advisory board). No competing interest since then. No link to companies that either produce or<br />
distribute ecigarettes.<br />
Funding<br />
No external funding<br />
Acknowledgements<br />
Vincent Baujard, from the HON Foundation, Geneva, Sw itzerland http://w w w.hon.ch developed the softw are for data<br />
collection.<br />
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Geneva, World Health Organization; 2008.<br />
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replacement therapies in smoking cessation: a systematic review of effectiveness and<br />
economic analysis.<br />
Health Technol Assess 2008, 12(2):iii-iv.<br />
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18. Etter JF, Perneger TV: A comparison of cigarette smokers recruited through the Internet or by<br />
mail.<br />
Int J Epidemiol 2001, 30(3):521-525. PubMed Abstract | Publisher Full Text<br />
19. Wang J, Etter JF: Administering an effective health intervention for smoking cessation online: the<br />
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20. Etter JF: Short-term change in self-reported COPD symptoms after smoking cessation in an<br />
Internet sample.<br />
Eur Respir J 2009, in press. PubMed Abstract | Publisher Full Text<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
29 Electronic cigarettes as a harm reduction strate-<br />
gy for tobacco control A step forward or a repeat<br />
of past mistakes
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Electronic cigarettes as a harm reduction strategy for tobacco control: A step forward or a repeat of past<br />
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Zachary Cahn and Michael Siegel<br />
BACK TO ARTICLE<br />
Table 1. Laboratory studies of the components in and safety of electronic cigarettes 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,<br />
15, 16, 17<br />
Study<br />
Evaluation of ecigarettes<br />
(FDA<br />
laboratory<br />
report) 5<br />
Safety Report<br />
on the Ruyan e-<br />
Cigarette<br />
Cartridge and<br />
Inhaled Aerosol6 Ruyan EcigaretteBenchtop<br />
Tests 7<br />
Characterization<br />
of Liquid<br />
‘Smoke Juice’<br />
for Electronic<br />
Cigarettes 8<br />
Analysis of<br />
Components<br />
from Gamucci<br />
Electronic<br />
Cigarette<br />
Cartridges,<br />
Tobacco Flavour<br />
Regular<br />
Smoking Liquid9 Analysis of<br />
Components<br />
from Gamucci<br />
Electronic<br />
Cigarette<br />
Cartridges,<br />
Tobacco Flavour<br />
Light Smoking<br />
Brand<br />
tested Main findings<br />
NJOY,<br />
Smoking<br />
Everywhere<br />
Figures and tables index<br />
Next table<br />
‘Very low levels’ of tobacco-specific nitrosamines (TSNAs) were detected in 5 of<br />
10 cartridges tested. Diethylene glycol (DEG) was detected about 0.1% in 1 of<br />
18 cartridges tested.<br />
Ruyan Trace levels of TSNAs were detected in the cartridge liquid. The average level of<br />
TSNAs was 3.9 ng/cartridge, with a maximum level of 8.2 ng/cartridge.<br />
Polyaromatic hydrocarbon carcinogens found in cigarette smoke were not<br />
detectable in cartridge liquid. No heavy metals detected. Exhaled carbon<br />
monoxide levels did not increase in smokers after use of the e-cigarette. The<br />
study concluded that e-cigarettes are very safe relative to cigarettes and safe in<br />
absolute terms on all measurements applied.<br />
Ruyan None of the 50 priority-listed cigarette smoke toxicants were detected. Toxic<br />
emissions score for e-cigarette was 0, compared to 100–134 for regular<br />
cigarettes.<br />
Liberty Stix No compounds detected via gas chromatography mass spectrometry (GC-MS)<br />
of electronic cigarette cartridges or vapors other than propylene glycol (99.1% in<br />
vapor), glycerin (0.46%), and nicotine (0.44%).<br />
Gamucci GC-MS detected propylene glycol (77.5%), glycerin (14.0%), nicotine (8.5%),<br />
and cyclotene hydrate (0.08%) in e-cigarette liquid. Levels of cyclotene hydrate<br />
were not believed to be of concern.<br />
Gamucci GC-MS detected propylene glycol (80.4%), glycerin (14.4%), and nicotine<br />
(5.3%) in e-cigarette liquid. No other compounds detected.
http://www.palgrave-journals.com/jphp/journal/v32/n1/fig_tab/jphp201041t1.html 2/3<br />
Liquid9 Analysis of<br />
Components<br />
from Gamucci<br />
Electronic<br />
Cigarette<br />
Cartridges, Ultra<br />
Light Smoking<br />
Liquid9 Analysis of<br />
Components<br />
from Gamucci<br />
Electronic<br />
Cigarette<br />
Cartridges,<br />
Tobacco Flavour<br />
Zero, Smoking<br />
Liquid9 NJOY e-<br />
Cigarette Health<br />
Risk<br />
Assessment 10<br />
Characterization<br />
of Regal<br />
Cartridges for<br />
Electronic<br />
Cigarettes 11<br />
Characterization<br />
of Regal<br />
Cartridges for<br />
Electronic<br />
Cigarettes –<br />
Phase II12 Analysis of<br />
Components<br />
from “e-Juice XX<br />
High 36 mg/ml<br />
rated Nicotine<br />
Solution”: ref<br />
S5543413 Analysis of<br />
Chemical<br />
Components<br />
from High, Med<br />
& Low Nicotine<br />
Cartridges 14<br />
Chemical<br />
Composition of<br />
“Instead”<br />
Electronic<br />
Cigarette<br />
Smoke Juice<br />
and Vapor15 Gas<br />
Chromatography<br />
Mass<br />
Gamucci GC-MS detected propylene glycol (85.5%), glycerin (11.2%), and nicotine<br />
(3.3%) in e-cigarette liquid. No other compounds detected.<br />
Gamucci GC-MS detected propylene glycol (84.3%), glycerin (7.6%), 1,3-bis(3phenoxyphenoxy)Benzene<br />
(7.0%), 3-Isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5tris(trimethylsiloxy)tetrasiloxane<br />
(0.77%), and α,3,4tris[(trimethylsilyl)oxy]Benzeneacetic<br />
acid (0.39%) in e-cigarette liquid. No other<br />
compounds were detected. 1,3-bis(3-phenoxyphenoxy) Benzene is nonhazardous.<br />
The other two chemicals have an unknown safety profile, but are<br />
present at nominally low levels.<br />
NJOY The vapor constituents detected were propylene glycol, glycerin, nicotine,<br />
acetaldehyde, 1-methoxy-2-propanol, 1-hydroxy-2-propanone, acetic acid, 1menthone,<br />
2,3-butanediol, menthol, carvone, maple lactone, benzyl alcohol, 2methyl-2-pentanoic<br />
acid, ethyl maltol, ethyl cinnamate, myosamine, benzoic<br />
acid, 2,3-bipyridine, cotinine, hexadecanoic acid, and 1’1-oxybis-2-propanol. No<br />
TSNAs, polyaromatic hydrocarbons, or other tobacco smoke toxicants were<br />
detected. On the basis of the amounts of these components present and an<br />
examination of the risk profile of these compounds, the report concludes that<br />
the only significant side effect expected would be minor throat irritation resulting<br />
from the acetaldehyde.<br />
inLife No DEG was detected in the cartridge liquid or vapors.<br />
inLife No TSNAs were detected in the e-cigarette liquid (limit of detection was 20<br />
ppm).<br />
e-Juice GC-MS detected propylene glycol (51.2%), 1,3-bis(3-phenoxyphenoxy)Benzene<br />
(20.2%), glycerin (15.0%), nicotine (10.0%), vanillin (1.2%), ethanol (0.5%), and<br />
3-cyclohexene-1-menthol,.α.,.α.4-trimethyl (0.4%). No other compounds<br />
detected. 1,3-bis(3-phenoxyphenoxy)Benzene is non-hazardous. Vanillin and 3cyclohexene-1-menthol,.α.,.α.4-trimethyl<br />
have unknown safety profiles.<br />
The<br />
Electronic<br />
Cigarette<br />
Company<br />
(UK)<br />
The compounds detected by GC-MS were propylene glycol, water, nicotine,<br />
ethanol, nitrogen, and triacetin. Triacetin is not known to be hazardous. No other<br />
compounds were detected.<br />
Instead No DEG was detected in e-cigarette liquid or vapor for the two products tested.<br />
Not<br />
specified<br />
GC-MS detected propylene glycol, glycerin, nicotine, caffeine, tetra-ethylene<br />
glycol, pyridine, methyl pyrrolyl, pyridine, methyl pyrrolidinyl, butyl-amine, and<br />
hexadecanoic acid in the e-cigarette liquid.
http://www.palgrave-journals.com/jphp/journal/v32/n1/fig_tab/jphp201041t1.html 3/3<br />
Spectrometry<br />
(GC-MS)<br />
Analysis<br />
Report 16<br />
Super Smoker<br />
Expert Report 17<br />
Super<br />
Smoker<br />
Journal of Public Health Policy ISSN 0197-5897 EISSN 1745-655X<br />
GC-MS detected propylene glycol, glycerin, nicotine, ethanol, acetone ethyl<br />
acetate, acetals, isobutyraldehyde, essential oils, and 2-methyl butanal in the ecigarette<br />
liquid. No other compounds were detected.<br />
Figures and tables index<br />
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BACK TO ARTICLE
30 Novel Nicotine.<br />
Nachschlagewerk zum Thema E-Zigaretten
Novel Nicotine<br />
Delivery<br />
Systems and<br />
Public Health:<br />
The Rise of the<br />
‘‘E-Cigarette’’<br />
Inhalation of smoke from burning<br />
tobacco remains the most deadly<br />
risky behavior in the United<br />
States. For years, corporations<br />
have sought alternative methods<br />
to administer nicotine to the brain<br />
without the harms of combustion<br />
while retaining the immediate<br />
rewarding aspects of cigarettes<br />
that make them so profitable,<br />
pleasurable, and addictive. The<br />
latest attempt at reduced harm<br />
products is a heterogeneous collection<br />
of battery-driven inhalers<br />
termed by the World Health Organization<br />
(WHO) as electronic<br />
nicotine delivery systems (ENDS) 1a<br />
or more popularly as electronic<br />
cigarettes or e-cigarettes. These<br />
devices pose significant challenges<br />
to the public health community<br />
because their distribution and use<br />
have become widespread in the<br />
United States while simultaneously<br />
evading most regulatory structures.<br />
Ultimately, these devices force<br />
a close consideration of how the<br />
health and regulatory system evaluates<br />
claims of safety and harm<br />
reduction in a dynamic, consumer<br />
driven environment to ensure the<br />
broad protection of public health.<br />
No standard definition of ENDS<br />
exists; different manufacturers use<br />
differing designs and incorporate<br />
a range of ingredients. Thus,<br />
a challenge to consumers, researchers,<br />
regulators, and policymakers<br />
is that specific attributes<br />
identified for any given ENDS<br />
brand may not apply to other<br />
brands. Three characteristics,<br />
however, appear common: (1)<br />
a cartridge containing a humectant<br />
carrier, such as propylene glycol,<br />
and often with nicotine in solution<br />
in different concentrations but no<br />
tobacco per se; (2) a tube into<br />
which the cartridge is inserted and<br />
through which the user inhales;<br />
and (3) a battery powered heating<br />
element across which the solution<br />
is drawn, causing the humectant to<br />
EDITORIALS<br />
vaporize, forming a mist. Distributors<br />
also sell bottles of ‘‘juice’’ to<br />
refill cartridges with solutions that<br />
can contain high concentrations of<br />
nicotine and other substances.<br />
Currently, the regulatory status<br />
of these devices remains in limbo<br />
in the United States. The Family<br />
Smoking and Tobacco Control<br />
Act of 2009 1b (HR 1256), provides<br />
for a new regulatory pathway<br />
for reduced harm products<br />
through the Food and Drug Administration<br />
(FDA) Center for<br />
Tobacco Products (CTP), but medicinal<br />
nicotine products remain<br />
regulated through the FDA Center<br />
for Drug Evaluation and<br />
Research (CDER). The CTP has<br />
a mandate to evaluate health<br />
claims provided by manufacturers,<br />
but inherent in the concept<br />
of harm reduction is a process of<br />
premarket evaluation and the demonstrable<br />
absence of unintended<br />
consequences on both health and<br />
behavior at individual and population<br />
levels. 2 Historically, tobacco<br />
companies have marketed oral and<br />
other noncombustible tobacco<br />
products purporting to reduce<br />
harm without actually providing<br />
evidence of such. In March 2010,<br />
RJ Reynolds was found liable for<br />
falsely claiming harm reduction for<br />
the Eclipse cigarette—a predecessor<br />
of ENDS that delivered nicotine<br />
in a heated glycol solution<br />
drawn through a tobacco plug. 3<br />
Until recently, attempts to<br />
market nicotine products outside<br />
of medicinal nicotine replacement<br />
therapy (NRT) were subject to<br />
regulatory hurdles. Products were<br />
either regulated (i.e., FDA approved)<br />
cessation aids, such as the<br />
nicotine patch, or clearly tobaccobased<br />
and unregulated, such as<br />
Eclipse. Nonpharmaceutical products<br />
containing nicotine (such as<br />
lollipops and water) have been<br />
rapidly removed from the market<br />
with little controversy. In general,<br />
addiction liability and physiological<br />
harm are greatest with inhaled<br />
tobacco smoke and least<br />
with medicinal NRT products. 2 In<br />
cigarettes and other tobacco products,<br />
the maximum dose of nicotine<br />
is limited by concentrations available<br />
in a fixed amount of tobacco. Although<br />
a cigarette may contain<br />
a highly toxic dose of 10–15mg of<br />
nicotine, serious poisoning is rare<br />
because presystemic metabolism<br />
and spontaneous vomiting limits the<br />
systemic absorption of nicotine in<br />
swallowed tobacco. 4 These upper<br />
limits may not apply to nicotine in<br />
high concentrations in ENDS or refill<br />
‘‘juice’’ bottles if inhaled, swallowed,<br />
or spilled on the skin. Thus, ENDS<br />
may introduce a new set of risks<br />
similar to those in nicotine-based<br />
pesticides and not normally present<br />
in leaf tobacco products.<br />
WHAT REALLY MATTERS<br />
TO THE PUBLIC HEALTH<br />
COMMUNITY?<br />
Cigarettes remain a major<br />
source of preventable mortality.<br />
An alternative to smoking that<br />
reduces exposure to toxins from<br />
tobacco combustion may be an<br />
acceptable strategy for harm<br />
reduction, provided it is evaluated<br />
on a premarket basis and introduces<br />
no new deleterious effects<br />
on either health or unintended<br />
changes in patterns of tobacco use<br />
behavior in the broader context of<br />
public health. 2,5 In adopting a<br />
harm-reduction language, manufacturers<br />
have promoted ENDS as<br />
an alternative to cigarettes rather<br />
than as a cessation aid, although<br />
ENDS are presumably used for<br />
cessation despite the absence of<br />
efficacy data. One manufacturer’s<br />
lawyer stated: ‘‘we don’t want<br />
people weaned off the e-cigarette,<br />
we want them smoking it as long<br />
as they smoked regular cigarettes.’’<br />
6 Proponents have claimed<br />
2340 | Editorials American Journal of Public Health | December 2010, Vol 100, No. 12
that ENDS are logically safer than<br />
cigarettes since they avoid or reduce<br />
most of the carcinogens from<br />
tobacco, particularly its combustion.<br />
5,7 Despite claims, the novel<br />
construction of ENDS has raised<br />
new challenging concerns of other<br />
potential risks, including appeal to<br />
and addiction of children (especially<br />
when flavors like strawberry<br />
or chocolate are added), displacement<br />
of effective cessation, longterm<br />
inhalation of propylene<br />
glycol, chemical contamination,<br />
uncontrolled levels of nicotine,<br />
misleading advertising of contents,<br />
variable nicotine delivery leading<br />
to unclear absorption mechanics or<br />
even potentially lethal systemic<br />
delivery, and accidental ingestion<br />
by young children because ENDS<br />
and ‘‘juice’’ are generally not sold<br />
in child resistant containers, are<br />
readily obtained via the Internet,<br />
and, for some refill kits, even come<br />
with a syringe.<br />
WHAT DO WE CURRENTLY<br />
KNOW?<br />
BasedonFDAtesting 8 and independent<br />
testing of 2 ENDS<br />
brands by our group (Georgetown/<br />
Schroeder Institute; full report<br />
available on request), we know<br />
that despite claims, nicotine<br />
varies across manufacturers, devices,<br />
cartridges, and even puff to<br />
puff. Such variations make generalizations<br />
of any testing results<br />
difficult; nonetheless we found<br />
the nicotine in the tested ENDS<br />
cartridges was 3- to 5-fold less<br />
than claimed (Table 1). Ultimately,<br />
the nicotine in the delivered<br />
vapor in the products<br />
tested is a fraction of that in the<br />
cartridge, and plasma testing<br />
suggests that current designs<br />
produce little systemic delivery<br />
of nicotine. 8–10 This outcome<br />
maystemfromanynumberof<br />
reasons; our testing of one device<br />
demonstrated an abrupt falloff<br />
in delivery after the first 10<br />
puffs, possibly from a rectifiable<br />
manufacturing defect, such as<br />
inconsistent current delivery.<br />
Triggering lag time from the<br />
pressure sensor or heating element<br />
may produce a nonlinear<br />
delivery curve per puff, causing<br />
shorter test puffs to have low<br />
nicotine delivery and deeper inhalations<br />
to have much more.<br />
The pH of the delivered solution<br />
may result in an ionized form of<br />
nicotine that is slowly absorbed<br />
through the tissue membranes,<br />
delaying uptake. At minimum,<br />
the variability in tested ENDS<br />
indicates poor quality control, so<br />
TABLE 1—Summary of ENDS (E-Cigarette) Nicotine Testing<br />
Product Claim FDA Report 8<br />
Smoking Everywhere b<br />
Njoy c<br />
Nicotrol Inhaler d<br />
Nicotine/Cartridge a (mg) Nicotine/Puff (lg)<br />
GU/SI a<br />
Claim<br />
EDITORIALS<br />
FDA Report,<br />
per 100-mL Puff<br />
their addiction liability remains<br />
unclear.<br />
Based on products tested, our<br />
results and the FDA’s 8 confirm<br />
a manufacturer-sponsored study 11<br />
demonstrating tobacco specific<br />
impurities and nitrosamines in cartridges<br />
at much lower levels than<br />
those found in cigarette smoke.<br />
Potentially concerning, and consistent<br />
with poor quality control, was<br />
the presence of humectants other<br />
than propylene glycol—in our case,<br />
glycerin, and for the FDA 8 diethylene<br />
glycol. The latter has a history<br />
of mass poisonings and deaths<br />
when inadvertently substituted for<br />
propylene glycol in consumer<br />
products. 12 The additional presence<br />
of irritants, solvents, genotoxins,<br />
and animal carcinogens (e.g.,<br />
butyl acetate, diethyl carbonate,<br />
benzoic acid, quinoline, dioctyl<br />
phthalate 2,6-dimethyl phenol) is<br />
of unclear significance but needs<br />
further consideration.<br />
RESEARCH, REGULATION,<br />
AND POLICY<br />
IMPLICATIONS<br />
Although the tested ENDS delivered<br />
lower nicotine levels than<br />
advertised, without regulatory<br />
oversight there are no limits on<br />
increasing the dose or probability<br />
GU/SI,<br />
per 35-mL Puff<br />
16 5.98 3.23 60.5 NA 31.5 Not tested<br />
18 6.76 4.07 60.54 NA 26.8–43.2 1.0 for puffs 1–10 < 0.3 for puffs 11–50<br />
10 Not tested Not tested 50 15.2 Not tested<br />
Note. ENDS = electronic nicotine delivery system; FDA Report = US Food and Drug Administration Report 8 ; GU = Georgetown University<br />
SI = Schroeder Institute.<br />
a<br />
We tested 3 cartridges from each manufacturer under ISO (International Organization for Standards) smoking conditions; extracts were<br />
analyzed by gas chromatography by Arista Labs Inc. (Richmond, VA).<br />
b<br />
Smoking Everywhere Inc, Sunrise, FL.<br />
c<br />
Njoy Inc, Scottsdale, AZ.<br />
d<br />
Pfizer Inc, New York, NY.<br />
of accidental ingestion. Aftermarket<br />
selling of concentrated ‘‘juice’’<br />
is worrisome; one supplier touts<br />
a solution containing 54mg of<br />
nicotine per mL (over 1.5 g per<br />
30 mL bottle). 13 Propylene glycol<br />
is common in some oral and<br />
topical products but has not been<br />
studied rigorously for long-term<br />
inhalational safety in humans.<br />
Poor quality control raises additional<br />
concerns about other possibly<br />
lethal ingredients. Despite these<br />
concerns, the regulatory status of<br />
ENDS in the United States remains<br />
unclear. After asserting that ENDS<br />
are drug delivery systems, the FDA<br />
was met with a lawsuit. 14 The court<br />
ruling that ENDS are not drug<br />
delivery devices is under appeal,<br />
but the ruling is unclear about<br />
whether ENDS should be regulated<br />
by the FDA’s traditional<br />
CEDR or the new CTP. Critically,<br />
despite the FDA action, ENDS remain<br />
widely available in the United<br />
States, 14 although through regulation<br />
they have been effectively<br />
banned in many other countries<br />
such as Australia, Canada, Singapore<br />
and Brazil owing to lack of<br />
safety or efficacy data. 5<br />
The ENDS tested so far have<br />
demonstrated poor quality control;<br />
toxic contaminants, albeit at low<br />
levels; misrepresentation of the<br />
nicotine delivered; and insufficient<br />
evidence of overall public health<br />
benefit. Ongoing, rigorous safety<br />
testing is needed, including determining<br />
real-world use patterns and<br />
further laboratory testing across<br />
device constructions to determine<br />
actual systemic nicotine delivery<br />
and exposure to harmful constituents.<br />
We recognize a manufacturer’s<br />
desire to market their<br />
product and advocates who say<br />
ENDS are logically safer than cigarettes.<br />
However, to allow their<br />
unregulated sale on presumption<br />
is not protecting public health.<br />
ENDS should be removed from the<br />
December 2010, Vol 100, No. 12 | American Journal of Public Health Editorials | 2341
market and permitted back only if<br />
and when it has been demonstrated<br />
that they are safe, that their benefits<br />
outweigh their harms to overall<br />
public health, and that a comprehensive<br />
regulatory structure has<br />
been established under an appropriate<br />
FDA division. It is possible<br />
that ENDS-like devices will eventually<br />
provide safer alternatives to<br />
smoking that do not increase youth<br />
uptake, that foster cessation, and<br />
that are less harmful or addictive<br />
than cigarettes. Until then, health<br />
and safety claims based on assumptions<br />
are unacceptable. j<br />
Nathan K. Cobb, MD<br />
M. Justin Byron, MHS<br />
David B. Abrams, PhD<br />
Peter G. Shields, MD<br />
About the Authors<br />
Nathan K. Cobb, M. Justin Byron, and David<br />
B. Abrams are with the Schroeder Institute<br />
for Tobacco Research and Policy Studies,<br />
Legacy Foundation, Washington, DC, and<br />
the Department of Health, Behavior, and<br />
Society, the Johns Hopkins Bloomberg School<br />
of Public Health, Baltimore, MD. Peter G.<br />
ShieldsiswiththeLombardiComprehensive<br />
Cancer Center, Georgetown University School<br />
of Medicine, Washington, DC.<br />
Correspondence should be sent to Nathan<br />
Cobb, MD, Research Investigator, Schroeder<br />
Institute for Tobacco Research and Policy<br />
Studies, 1724 Massachusetts Avenue<br />
NW, Washington, DC 20036 (e-mail:<br />
ncobb@legacyforhealth.org). Reprints can<br />
be ordered at http://www.ajph.org by<br />
clicking the ‘‘Reprints/Eprints’’ link.<br />
This editorial was accepted July 26,<br />
2010.<br />
doi:10.2105/AJPH.2010.199281<br />
Contributors<br />
All authors contributed substantially to the<br />
authorship of the editorial. N. K. Cobb is the<br />
guarantor and accepts full responsibility<br />
for the work.<br />
Acknowledgments<br />
The study was funded in part by a grant<br />
from the National Cancer Institute<br />
(5R01CA114377; Laboratory-Based<br />
Evaluation of Tobacco Harm Reduction)<br />
and the American Legacy Foundation.<br />
References<br />
1a. World Health Organization Study<br />
Group on Tobacco Regulation. Tobreg<br />
scientific recommendation: devices<br />
designed for the purpose of nicotine delivery<br />
to the respiratory system in which<br />
tobacco is not necessary for their operation.<br />
In: Report on the Scientific Basis of<br />
Tobacco Product Regulation: Third Report<br />
of a WHO Study Group. Geneva: World<br />
Health Organization; 2009.<br />
1b. US Food and Drug Administration.<br />
Family Smoking Prevention and Tobacco<br />
Control Act. Pub L No. 111-31, 123<br />
Stat 1776 (2009). Available at: http://<br />
frwebgate.access.gpo.gov/cgi-bin/getdoc.<br />
cgi?dbname=111_cong_public_laws<br />
&docid=f:publ031.111 Accessed October<br />
26, 2010.<br />
2. Zeller M, Hatsukami D, Strategic Dialogue<br />
on Tobacco Harm Reduction<br />
Group. The strategic dialogue on tobacco<br />
harm reduction: A vision and blueprint<br />
for action in the US. Tob Control. 2009;<br />
18(4):324–332.<br />
3. State of Vermont v. RJ Reynolds Tobacco<br />
Co. 2010: Available at: http://www.<br />
vermontjudiciary.org/TCDecisionCvl/<br />
2010-3-10-1.pdf. Accessed March 12,<br />
2010.<br />
4. Centers for Disease Control and Prevention<br />
(CDC). Ingestion of cigarettes and<br />
cigarette butts by children–Rhode Island.<br />
MMWR Morb Mortal Wkly Rep. 1997;<br />
46(6):125–128.<br />
5. Henningfield JE, Zaatari GS. Electronic<br />
nicotine delivery systems: emerging<br />
science foundation for policy. Tob<br />
Control. 2010;19(2):89–90.<br />
6. Lawyers ask judge to lift ban on<br />
electronic cigarettes. Available at:<br />
http://www.law.com/jsp/article.jsp?id=<br />
1202433141202&rss=newswire.<br />
Accessed November 25, 2009.<br />
7. Seigel M. Electronic cigarettes jolt<br />
cynical opposition [Op-Ed]. Boston Herald.<br />
May 11, 2009. Available at: http://www.<br />
bostonherald.com/news/opinion/op_ed/<br />
view2009_05_11_Electronic_cigarettes_<br />
jolt_cynical_opposition. Accessed March<br />
12, 2010.<br />
8. US Food and Drug Administration.<br />
Evaluation of e-cigarettes. 2009. Available<br />
at: http://www.fda.gov/downloads/<br />
Drugs/ScienceResearch/UCM173250.<br />
pdf. Accessed March 6, 2010.<br />
9. Eissenberg T. Electronic nicotine delivery<br />
devices: Ineffective nicotine delivery<br />
and craving suppression after acute administration.<br />
Tob Control. 2010;19(1):87–88.<br />
10. Bullen C, McRobbie H, Thornley S,<br />
Glover M, Lin R, Laugesen M. Effect of<br />
an electronic nicotine delivery device<br />
(e cigarette) on desire to smoke and<br />
withdrawal, user preferences and nicotine<br />
delivery: randomised cross-over trial. Tob<br />
Control. 2010;19(2):98–103.<br />
11. Laugesen M. Safety Report on the<br />
Ruyan E-Cigarette Cartridge and Inhaled<br />
EDITORIALS<br />
Aerosol. Christchurch, New Zealand:<br />
Health New Zealand Ltd; 2008.<br />
12. Schep LJ, Slaughter RJ, Temple WA,<br />
Beasley DM. Diethylene glycol poisoning.<br />
Clin Toxicol (Phila). 2009;47(6):525–535.<br />
13. Totally Wicked USA. Totally<br />
wicked e-liquid. Available at: http://www.<br />
totallywicked-eliquid.com/products/<br />
totally-wicked-e-liquid/platinum-ice-54mgmixed-juice-product.html.<br />
Accessed April<br />
12, 2010.<br />
14. Duff W. Judge orders FDA to stop<br />
blocking imports of e-cigarettes from<br />
china. New York Times. January 14, 2010.<br />
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2010/01/15/business/15smoke.html.<br />
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2342 | Editorials American Journal of Public Health | December 2010, Vol 100, No. 12
Nachschlagewerk zum Thema E-Zigaretten<br />
31 Electronic-cigarette smoking experience among<br />
adolescents
http://www.ncbi.nlm.nih.gov/pubmed/22018571 1/2<br />
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J Adolesc Health. 2011 Nov;49(5):542-6. doi: 10.1016/j.jadohealth.2011.08.001.<br />
Electronic-cigarette smoking experience among adolescents.<br />
Cho JH, Shin E, Moon SS.<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Department of Health Administration, Hanyang Women's University, Seoul, Republic of Korea.<br />
Abstract<br />
OBJECTIVES: To investigate the level of awareness and contact routes to electronic cigarette (ecigarette),<br />
and to identify significant factors that may affect adolescent use of e-cigarettes; this<br />
study explores the experience of e-cigarettes among adolescents.<br />
METHODS: Using the data from the 2008 Health Promotion Fund Project in Korea, we used a<br />
hierarchical logistic regression analysis to evaluate gender, level of school, family smoking,<br />
perception of peer influence, satisfaction in school life, and cigarette smoking experience as<br />
predictors of trying e-cigarettes among adolescents in five schools in Korea.<br />
RESULTS: Overall, 444 (10.2%) students responded as having seen or heard of e-cigarettes.<br />
Twenty-two (.5%) students reported as having used an e-cigarette. The contact routes of information<br />
on e-cigarettes were the Internet (249, 46.4%), friends (150, 27.9%), television (59, 11.0%), books<br />
(50, 9.3%), and others (29, 5.4%). The following factors were determined to be statistically<br />
significant predictors of e-cigarette experience: male gender, perception of peer influence,<br />
satisfaction in school life, and cigarette smoking experience.<br />
CONCLUSIONS: In light of this fact, continuous attention needs to be paid on the marketing of ecigarettes<br />
on Internet sites to prevent adolescents from being exposed to unsupported claims about<br />
e-cigarettes and to provide appropriate information on health effects.<br />
Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights<br />
reserved.<br />
PMID: 22018571 [PubMed - indexed for MEDLINE]<br />
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Electronic cigarette: users<br />
profile, utilization, [Addiction. satisfaction 2011]<br />
Monitoring polytobacco use<br />
among adolescents: [Nicotine Tob do Res. cigarette 2008]<br />
Peers, schools, and adolescent<br />
cigarette [J smoking. Adolesc Health. 2001]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
32 Successful smoking cessation with electronic<br />
cigarettes in smokers with a documented history<br />
of recurring relapses a case series.
http://www.ncbi.nlm.nih.gov/pubmed/22185668 1/2<br />
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J Med Case Rep. 2011 Dec 20;5(1):585. doi: 10.1186/1752-1947-5-585.<br />
Successful smoking cessation with electronic cigarettes in smokers with a<br />
documented history of recurring relapses: a case series.<br />
Caponnetto P, Polosa R, Russo C, Leotta C, Campagna D.<br />
Centro per la Prevenzione e Cura del Tabagismo (CPCT), Dipartimento di Biomedicina Clinica e Molecolare, Azienda<br />
Ospedaliero-Universitaria "V, Emanuele-Policlinico", Università di Catania, Catania, Italy. p.caponnetto@unict.it.<br />
Abstract<br />
INTRODUCTION: Smoking cessation programs are useful in helping smokers to quit, but smoking<br />
is a very difficult addiction to break and the need for novel and effective approaches to smoking<br />
cessation interventions is unquestionable. The E-cigarette is a battery-powered electronic nicotine<br />
delivery device that may help smokers to remain abstinent during their quit attempt. We report for<br />
the first time objective measures of smoking cessation in smokers who experimented with the Ecigarette.<br />
CASE PRESENTATION: Three Caucasian smokers (two men aged 47 and 65 years and one<br />
woman aged 38 years) with a documented history of recurring relapses were able to quit and to<br />
remain abstinent for at least six months after taking up an E-cigarette.<br />
CONCLUSIONS: This is the first time that objective measures of smoking cessation are reported<br />
for smokers who quit successfully after using an E-cigarette. This was accomplished in smokers<br />
who repeatedly failed in previous attempts with professional smoking cessation assistance using<br />
the usual nicotine dependence treatments and smoking cessation counselling.<br />
PMID: 22185668 [PubMed] PMCID: PMC3276453 Free PMC Article<br />
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delivery [BMC device Public (e-Cigarette) Health. 2011] on<br />
Predictors of smoking cessation<br />
in a cohort of adult [Tob Control. smokers1997]<br />
Review [Smoking reduction and<br />
temporary abstinence: [J Mal Vasc. new 2003]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
33 Effect of an electronic nicotine delivery device e<br />
cigarette on desire to smoke and withdrawal, us-<br />
er preferences and nicotine delivery randomised<br />
cross-over trail.
http://tobaccocontrol.bmj.com/content/19/2/98.abstract 1/3<br />
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Home > Volume 19, Issue 2 > Article<br />
Tob Control 2010;19:98-103 doi:10.1136/tc.2009.031567<br />
Research paper<br />
Effect of an electronic nicotine delivery device (e<br />
cigarette) on desire to smoke and withdrawal, user<br />
preferences and nicotine delivery: randomised<br />
cross-over trial<br />
C Bullen 1 , H McRobbie 2 , S Thornley 3 , M Glover 4 , R Lin 5 , M Laugesen 6<br />
+<br />
Author Affiliations<br />
Correspondence to<br />
Dr Christopher Bullen, Clinical Trials Research Unit, The University of Auckland, Private Bag<br />
92019, Auckland, New Zealand; c.bullen@ctru.auckland.ac.nz<br />
Contributors CB, HM, ST, MG, RL and ML designed and conducted the study, interpreted the<br />
data, and wrote the manuscript. CB, HM and ST are guarantors.<br />
Received 15 May 2009<br />
Accepted 2 December 2009<br />
Abstract<br />
Objectives To measure the short-term effects of an electronic nicotine delivery device (“e<br />
cigarette”, ENDD) on desire to smoke, withdrawal symptoms, acceptability, pharmacokinetic<br />
properties and adverse effects.<br />
Design Single blind randomised repeated measures cross-over trial of the Ruyan V8 ENDD.<br />
Setting University research centre in Auckland, New Zealand.<br />
Participants 40 adult dependent smokers of 10 or more cigarettes per day.<br />
Interventions Participants were randomised to use ENDDs containing 16 mg nicotine or 0<br />
mg capsules, Nicorette nicotine inhalator or their usual cigarette on each of four study days 3<br />
days apart, with overnight smoking abstinence before use of each product.<br />
Main outcome measures The primary outcome was change in desire to smoke, measured<br />
as “area under the curve” on an 11-point visual analogue scale before and at intervals over 1<br />
h of use. Secondary outcomes included withdrawal symptoms, acceptability and adverse<br />
events. In nine participants, serum nicotine levels were also measured.<br />
Results Over 60 min, participants using 16 mg ENDD recorded 0.82 units less desire to<br />
smoke than the placebo ENDD (p=0.006). No difference in desire to smoke was found<br />
between 16 mg ENDD and inhalator. ENDDs were more pleasant to use than inhalator<br />
(p=0.016) and produced less irritation of mouth and throat (p><br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
34 Electronic cigarettes as a method of tobacco<br />
control.
http://www.bmj.com/content/343/bmj.d6269 1/3<br />
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EDITORIAL<br />
Electronic cigarettes as a method of<br />
tobacco control<br />
BMJ 2011; 343 doi: http://dx.doi.org/10.1136/bmj.d6269 (Published 30 September 2011)<br />
Cite this as: BMJ 2011;343:d6269<br />
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Ron Borland, Nigel Gray distinguished fellow in cancer prevention<br />
Author Affiliations<br />
ron.borland@cancervic.org.au<br />
Allow them, but research and monitoring are needed so that the risks can be<br />
regulated<br />
Electronic cigarettes (e-cigarettes), cigarette shaped products that vaporise nicotine<br />
in ways that enable it to be inhaled, have become increasingly popular in the past<br />
few years.1 2 3 E-cigarettes are a potentially more attractive substitute for smoking<br />
than low toxin smokeless tobacco because the nicotine is delivered by puffing, as<br />
when smoking a cigarette. A range of products are now on the market, with new<br />
improved ones promised, and—something almost unheard of in tobacco use—self<br />
organising groups of users (who call themselves “vapers” because they inhale<br />
vapour, not smoke)—who are advocating for these products and sharing their<br />
experiences.1 3 Opposition has come from some health groups, either for<br />
pragmatic reasons or because they are opposed to any recreational use of nicotine.<br />
Medical journals including the BMJ have called for more research or regulation (or<br />
both),4 5 6 7 8 with the main difference being whether this should occur before<br />
allowing the products on to the market,4 or accepting that they might continue to be<br />
allowed.5 6 7 8<br />
People who argue that research is needed first …<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
35 WHO Study Group on Tobacco Product Regula-<br />
tion.
WHO Technical Report Series<br />
955<br />
WHO STUDY GROUP ON<br />
TOBACCO PRODUCT<br />
REGULATION<br />
Report on the Scientific Basis<br />
of Tobacco Product Regulation:<br />
Third Report of a WHO Study Group
WHO Technical Report Series<br />
955<br />
WHO STUDY GROUP ON<br />
TOBACCO PRODUCT REGULATION<br />
report on the scientific basis of<br />
tobacco product regulation: third report<br />
of a WHO study group
WHO Library Cataloguing-in-Publication Data<br />
WHO study group on tobacco product regulation: report on the scientific basis of tobacco product regulation:<br />
third report of a WHO study group.<br />
(WHO technical report series ; no. 955)<br />
1.Tobacco use disorder - prevention and control. 2.Tobacco industry - legislation. 3.Tobacco control<br />
campaigns. 4. Tobacco-derived products labelling. 5.Tobacco-derived products packing. I.World Health<br />
Organization. II.Series.<br />
ISBN 978 92 4 120955 7 (NLM classification: QV 137)<br />
ISSN 0512-3054<br />
© World Health Organization 2009<br />
All rights reserved. Publications of the World Health Organization can be obtained from WHO Press,<br />
World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264;<br />
fax: +41 22 791 4857; e-mail: bookorders@who.int). Requests for permission to reproduce or translate WHO<br />
publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the<br />
above address (fax: +41 22 791 4806; e-mail: permissions@who.int).<br />
The designations employed and the presentation of the material in this publication do not imply the expression<br />
of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any<br />
country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.<br />
Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.<br />
The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed<br />
or recommended by the World Health Organization in preference to others of a similar nature that are not<br />
mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial<br />
capital letters.<br />
All reasonable precautions have been taken by the World Health Organization to verify the information<br />
contained in this publication. However, the published material is being distributed without warranty of any kind,<br />
either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader.<br />
In no event shall the World Health Organization be liable for damages arising from its use.<br />
This publication contains the collective views of an international group of experts and does not necessarily<br />
represent the decisions or the policies of the World Health Organization.<br />
Typeset in India<br />
Printed in Switzerland
Contents<br />
1. Introduction<br />
1.1 Background<br />
2. TobReg Scientific Recommendation: Devices designed for the<br />
purpose of nicotine delivery to the respiratory system in which<br />
tobacco is not necessary for their operation<br />
2.1 Preface<br />
2.2 Definition of ENDS<br />
2.3 Types and distribution<br />
2.4 Substances in addition to nicotine<br />
2.5 Concern about lung delivery<br />
2.6 Nicotine addiction as the basis for ENDS marketing<br />
2.7 ENDS are not nicotine replacement therapy<br />
2.8 Capacity of ENDS to serve as nicotine replacement therapy<br />
2.9 Regulatory status<br />
2.10 Other concerns<br />
2.11 Conclusions<br />
2.12 Recommendations for regulatory policy<br />
2.13 Recommendations for clinical trials and other research<br />
required forregulatory approval<br />
2.14 References<br />
Annex 1. International regulatory measures for<br />
electronicnicotine delivery systems (ENDS)<br />
3. Report on setting regulatory limits for carcinogens in smokeless<br />
tobacco<br />
3.1 Background<br />
3.2 Carcinogens present in smokeless tobacco<br />
3.3 Tobacco-specific nitrosamines and polycyclic aromatic<br />
hydrocarbons<br />
Table 1. Concentrations of tobacco-specific N-nitrosamines in<br />
selected smokeless tobacco products (μg/g dry weight<br />
of tobacco)<br />
Table 2. Concentrations of tobacco-specific nitrosamines<br />
(TSNA) and benzo[a]pyrene in smokeless tobacco products<br />
purchased in the United Kingdom and elsewhere<br />
Table 3. Concentrations of tobacco-specific nitrosamines<br />
(TSNA) and benzo[a]pyrene in smokeless tobacco<br />
products sold in the United States<br />
3.4 Differences in carcinogens present in smokeless tobacco<br />
by region<br />
3.5 Targets for regulation<br />
3.6 Selection of metric for regulation<br />
3.7 Selection of achievable levels for tobacco-specific<br />
N-nitrosamines and benzo[a]pyrene in smokeless tobacco<br />
3.8 Regulatory considerations and communication of regulatory<br />
values and testing results to the public<br />
1<br />
2<br />
3<br />
3<br />
4<br />
5<br />
5<br />
6<br />
6<br />
7<br />
8<br />
8<br />
9<br />
10<br />
10<br />
11<br />
11<br />
13<br />
23<br />
23<br />
24<br />
25<br />
27<br />
28<br />
29<br />
26<br />
30<br />
30<br />
32<br />
34<br />
iii
iv<br />
3.9 Recommendations<br />
3.10 Acknowledgement<br />
3.11 References<br />
4. Overall recommendations<br />
4.1 Electronic nicotine delivery systems (ENDS): regulatory<br />
recommendations and research needs<br />
4.2 Smokeless tobacco: setting regulatory limits for carcinogenic<br />
components<br />
36<br />
36<br />
37<br />
39<br />
39<br />
40
WHO Study Group on Tobacco Product Regulation<br />
Durban, South Africa, 12–14 November 2008<br />
Members<br />
Dr D.L. Ashley, Chief, Emergency Response and Air Toxicants<br />
Branch, Centers for Disease Control and Prevention, Atlanta,<br />
Georgia, United States of America<br />
Dr O.A. Ayo-Yusuf, Associate Professor, School of Dentistry,<br />
University of Pretoria, South Africa<br />
Dr D. M. Burns, Professor Emeritus of Family and Preventive<br />
Medicine, School of Medicine, University of California at San<br />
Diego, San Diego, California, United States of America<br />
Dr Vera Luiza da Costa e Silva, Independent Consultant, Senior<br />
Public Health Specialist, Rio de Janeiro, Brazil<br />
Dr M. Djordjevic, Program Director, National Cancer Institute,<br />
Division of Cancer Control and Population Sciences, Tobacco<br />
Control Research Branch, Bethesda, Maryland, United States<br />
of America<br />
Dr N. Gray, Honorary Senior Associate, Cancer Council Victoria,<br />
Melbourne, Australia<br />
Dr S.K. Hammond, Professor of Environmental Health Sciences,<br />
School of Public Health, University of California at Berkeley,<br />
Berkeley, California, United States of America<br />
Dr J. Henningfield, Professor (Adjunct), Behavioral Biology,<br />
Johns Hopkins University School of Medicine; Vice President,<br />
Research and Health Policy, Pinney Associates, Bethesda,<br />
Maryland, United States of America<br />
Dr M. Jarvis, Principal Scientist, Cancer Research UK, Health<br />
Behaviour Unit, Royal Free and University College London<br />
Medical School, London, England<br />
v
Dr A. Opperhuizen, Head of the Laboratory for Health Protection<br />
Research, National Institute for Public Health and the<br />
Environment, Bilthoven, The Netherlands<br />
Dr K.S. Reddy, Professor of Cardiology, All India Institute of<br />
Medical Sciences, New Delhi, India<br />
Dr C. Robertson, Ruth G. and William K. Bowes Professor in the<br />
School of Engineering, Department of Chemical Engineering,<br />
Stanford University, Stanford, California, United States of<br />
America<br />
Dr G. Zaatari (Chair), Professor, Department of Pathology and<br />
Laboratory Medicine, American University of Beirut, Beirut,<br />
Lebanon<br />
Secretariat<br />
vi<br />
Dr D.W. Bettcher, Director, Tobacco Free Initiative, WHO,<br />
Geneva, Switzerland<br />
Mr R. Minhas, Technical Officer, Tobacco Free Initiative, WHO,<br />
Geneva, Switzerland<br />
Ms E. Tecson, Administrative Assistant, Tobacco Free Initiative,<br />
WHO, Geneva, Switzerland<br />
Ms G. Vestal, Technical Officer, Tobacco Free Initiative, WHO,<br />
Geneva, Switzerland
1. Introduction<br />
The fifth meeting of the WHO Study Group on Tobacco Product Regulation<br />
(TobReg) was held in Durban, South Africa on 12–14 November 2008.<br />
TobReg is mandated to provide the WHO Director-General with scientifically<br />
sound, evidence-based recommendations to Member States about tobacco<br />
product regulation. In line with the provisions of Articles 9 and 10 of<br />
the WHO Framework Convention on Tobacco Control, TobReg identifies<br />
approaches for regulating tobacco products that pose significant public health<br />
issues and raise questions for tobacco control policy.<br />
At its fifth meeting, the Study Group addressed regulation of electronic<br />
cigarettes, smokeless tobacco toxicants, ‘roll-your-own’ products, products<br />
marketed as cessation aids, particles in smoke and menthol. The meeting<br />
followed a WHO press release on 19 September 2008, which asserted that<br />
WHO does not consider electronic cigarettes to be a legitimate tobacco cessation<br />
therapy. The press release stressed that, as no rigorous, peer-reviewed<br />
studies have been conducted to show that electronic cigarettes are a safe,<br />
effective nicotine replacement therapy (NRT), there is no evidence to support<br />
marketing of these products for tobacco cessation.<br />
This report presents the conclusions and recommendations of the Study<br />
Group at its fifth meeting on two products, both of which represent potential<br />
harm to public health and the promotion, sale and use of which are inadequately<br />
regulated:<br />
electronic nicotine delivery systems (ENDS), which deliver nicotine and<br />
other substances directly to the lung without products of tobacco combustion;<br />
and<br />
smokeless tobacco products, which are marketed in various regions of the<br />
world and vary substantially in their content and carcinogenicity.<br />
The following two sections of this report present the Study Group’s recommendations<br />
in relation to each product. Its overall recommendations are<br />
summarized in section 4.<br />
1
1.1 Background<br />
2<br />
Regulation of tobacco products is essential for tobacco control and is endorsed<br />
by the WHO Framework Convention on Tobacco Control in provisions of its<br />
Articles 9, 10 and 11. Regulation serves public health goals by providing an<br />
understanding of tobacco products and meaningful surveillance of their manufacture,<br />
packaging, labelling and distribution. The scientific basis of the<br />
principles that guide implementation of the Articles creates synergy and mutual<br />
reinforcement of the regulatory practices described in each Article.<br />
Tobacco product regulation includes regulation of the contents and emissions<br />
of tobacco products by testing, measuring and mandating disclosure of the<br />
results and regulating their packaging and labelling. Governmental supervision<br />
is required of manufacture and of enforcement of the regulations governing<br />
the design, contents and emissions of tobacco products, as well as their<br />
distribution, packaging and labelling, with the aim of protecting and promoting<br />
public health.<br />
Chemical consumer products are usually regulated after a review of the scientific<br />
evidence on the hazards presented by the product, the exposure likely<br />
to occur, the patterns of use and the marketing messages of the manufacturer.<br />
Many jurisdictions require manufacturers to classify and label products according<br />
to their hazardous properties, to control the hazardous contents or to<br />
limit the advertising, promotion and sponsorship of such products. ENDS<br />
deliver nicotine and other substances but do not contain tobacco, and smokeless<br />
tobacco is produced in ‘cottage’ industries or can be modified significantly<br />
by the end user. Both therefore pose a significant challenge to<br />
regulation, as they may fall outside the scope of domestic regulatory regimes<br />
for tobacco products. Nevertheless, their popularity and the fact that they are<br />
marketed as alternatives to cigarette smoking indicate the need to characterize<br />
them, regulate them and establish appropriate educational programmes to<br />
limit their use.<br />
TobReg reviews the scientific evidence on topics related to tobacco product<br />
regulation and identifies the research needed to fill regulatory gaps in tobacco<br />
control. The Study Group is composed of national and international scientific<br />
experts on product regulation, treatment of tobacco dependence and laboratory<br />
analysis of tobacco ingredients and emissions. As a formalized entity of<br />
WHO, the Study Group reports to the WHO Executive Board through the<br />
Director-General to draw the attention of Member States to the Organization’s<br />
work in tobacco product regulation, which is a complex area of tobacco<br />
control.<br />
The Study Group hopes that the recommendations contained in this report,<br />
as well as its other recommendations and advisory notes, will be useful to<br />
countries in implementing the product regulation provisions of the WHO<br />
Framework Convention on Tobacco Control.
2. TobReg Scientific Recommendation:<br />
Devices designed for the purpose of<br />
nicotine delivery to the respiratory<br />
system in which tobacco is not<br />
necessary for their operation<br />
2.1 Preface<br />
This Scientific Recommendation addresses electronic nicotine delivery systems<br />
(ENDS) designed for nicotine delivery to the respiratory system. This<br />
designation encompasses products that contain tobacco-derived substances<br />
but in which tobacco is not necessary for their operation. ENDS are marketed<br />
under a variety of brand names and descriptors, including ‘electronic<br />
cigarettes’, ‘ecigarro’, ‘electro-smoke’, ‘green cig’ and ‘smartsmoker’.<br />
This recommendation is being made because ENDS pose significant public<br />
health issues and raise questions for tobacco control policy and regulation.<br />
Manufacturers have not fully disclosed the chemicals used in ENDS; there<br />
are few data on their emissions or actual human exposure; their health effects<br />
have not been studied; and their marketing and use could undermine public<br />
smoking bans, which are important tobacco control interventions. The products<br />
could also undermine smoking cessation efforts by proposing unproven<br />
devices for smoking cessation in the place of products of proven efficacy.<br />
ENDS might also undermine the prevention of tobacco use because of their<br />
appearance and marketing as safe alternatives to tobacco products for nontobacco<br />
users, including children.<br />
ENDS are marketed internationally on the Internet and by direct consumer<br />
marketing in some countries. Market penetration of unregulated ENDS has<br />
expanded rapidly to most WHO regions, primarily from China, where most<br />
of the products are manufactured. Increasing access to these largely unregulated<br />
products must be addressed by rational regulatory policy.<br />
ENDS fall into a regulatory gap in most countries, escaping regulation as<br />
drugs and avoiding the controls levied on tobacco products. Thus, policymakers<br />
and consumers lack evidence-based information and recommendations.<br />
Regulatory control of ENDS is confounded by their international<br />
availability from online retailers and distributors. In Bulgaria, for example,<br />
a number of online retailers sell the product for the equivalent of US$70, and<br />
nicotine cartridges retail for US$10 each, independently of the labelled nicotine<br />
content. In addition, ENDS are being introduced in countries such as<br />
3
Lebanon as products that are imported from China. Thus, it has become urgent<br />
to evaluate the safety of the products and the data supporting the claims for<br />
their safety and efficacy.<br />
Policy-makers in many countries have sought guidance from WHO on the<br />
scientific evidence and regulatory approaches with regard to ENDS, enquiring<br />
whether they should be regulated as tobacco products, drugs or a combination<br />
of drugs and medical devices, and what information on safety should<br />
be communicated to consumers. An important regulatory consideration is the<br />
validity of the marketing claims made for the products, which include statements<br />
that ENDS are smoking cessation aids and that they deliver safer<br />
nicotine but at variable levels compared to those in cigarettes. Other practical<br />
regulatory questions include whether use of ENDS should be exempt from<br />
restrictions in places where smoking is prohibited, a claim supported by some<br />
manufacturers and distributors.<br />
This Recommendation includes conclusions and recommendations for regulatory<br />
policy and recommendations for clinical trials and other research. It is<br />
an extension of earlier recommendations from the Scientific Advisory Committee<br />
on Tobacco Product Regulation (SACTob) and TobReg and is designed<br />
to provide a foundation for regulation that will advance tobacco<br />
control in general. This Recommendation was formulated in the context of<br />
the WHO Framework Convention on Tobacco Control, particularly to aid<br />
Parties to the treaty in implementing Articles 9, 10, 11 and 14. In addition,<br />
further guidance for implementation of Article 8, which requires protection<br />
from exposure to tobacco smoke, is vital, because the advertisements of many<br />
of the manufacturers of ENDS state that they can be used in environments<br />
where smoking is prohibited, on the basis of their claim that these products<br />
do not produce smoke.<br />
2.2 Definition of ENDS<br />
4<br />
Electronic nicotine delivery systems (ENDS) are a category of consumer<br />
products designed to deliver nicotine to the lungs after one end of a plastic<br />
or metal cylinder is placed in the mouth, like a cigarette or cigar, and inhaled<br />
to draw a mixture of air and vapours from the device into the respiratory<br />
system. They contain electronic vaporization systems, a rechargeable battery<br />
and charger, electronic controls and replaceable cartridges that may contain<br />
nicotine and other chemicals. Some brands are claimed to deliver a range of<br />
nicotine concentrations or no nicotine at all, and some are claimed to provide<br />
sensory experiences similar to those obtained with major cigarette brands.<br />
The chemicals used to produce the odours and flavours that simulate those<br />
of cigarettes have not all been identified, although some products claim to<br />
include ‘menthol’. Some devices have light-emitting diodes, to reproduce the
appearance of a burning cigarette tip. The premise stated by some marketers<br />
of the products is that ENDS provide nicotine that would otherwise be obtained<br />
by tobacco use. The figures below show prototype devices.<br />
Rechargeable Battery<br />
Indicator Light<br />
Battery<br />
2.3 Types and distribution<br />
Vaporizing Chamber<br />
Replaceable Ingredients Cartridge<br />
Electronic Circuit Cartridge<br />
Atomizer<br />
Tip<br />
Inhaler<br />
It is not clear how many manufacturers of ENDS exist, but an Internet search<br />
revealed at least 24 licensed companies and many more brands and model<br />
names. It is not clear whether products of similar appearance from other companies<br />
have identical contents, deliveries and effects on the body; it is possible<br />
that different devices represent different hazards and effects. The number of<br />
product types and brands described and marketed on the Internet and by retail<br />
stores is increasing rapidly. In addition, the inadequacy of customs product<br />
codes makes it difficult for regulators to track importation accurately.<br />
Distributors market ENDS in many countries and regions, including Australia,<br />
Brazil, China, Europe, the Republic of Korea and the United States of<br />
America. In view of the number and diversity of ENDS, the content, design<br />
and delivery characteristics of each product must be measured, as it cannot<br />
be assumed that their effects are similar. Regulation should ensure that every<br />
product marketed to the public has been approved after disclosure of content,<br />
manufacturing method and data on safety appropriate to each product.<br />
2.4 Substances in addition to nicotine<br />
Various ENDS marketers claim that their products mimic the sensory effects<br />
of cigarettes with markedly different characteristics, suggesting that ENDS<br />
cartridges contain several chemicals in addition to nicotine. The manufacturers<br />
have not fully disclosed the chemical combinations included during<br />
5
manufacture or synthesized during electronic vaporization that produce such<br />
sensory effects. Furthermore, the manufacturers have not proven that the<br />
constituent chemicals—which include organic chemicals that may be acceptable<br />
for use in foods and cosmetics—are safe for inhalation when<br />
vaporized and delivered to the lung. Although some manufacturers have disclosed<br />
the identity of some chemicals, full disclosure of the chemical components<br />
of ENDS and their evaluation for potential toxicity are regulatory<br />
priorities.<br />
The United States Food and Drug Administration recently analysed the<br />
chemicals in 18 varieties of ENDS cartridges marketed with two different<br />
brands of ENDS and found significant variation in contents and deliveries.<br />
Several contained “detectable levels of nitrosamines, tobacco-specific compounds<br />
known to cause cancer” (1). The Administration’s testing also revealed<br />
that the nicotine levels were inconsistent with the information on the<br />
cartridge labels and that some cartridges that were stated not to contain nicotine<br />
actually did.<br />
2.5 Concern about lung delivery<br />
Other products target the lung for safe, effective drug delivery (e.g. insulin<br />
inhalers), and scientific advances in the delivery of drugs to the lungs of<br />
animals and humans could be adapted to develop safe systems for delivering<br />
nicotine to the lung. Although the medical advances were gradual and costly,<br />
regulatory authorities have consistently required manufacturers to establish<br />
a rigorous scientific foundation for product approval.<br />
Delivery of nicotine to the lung raises concern about safety and addiction that<br />
go beyond that related to currently approved NRT. Concern about the safety<br />
of ENDS is associated with the probable exposure of the lung to repeated<br />
dosing, perhaps hundreds of times a day for many months, if these products<br />
are used as a smoking cessation aid, or for years, for smokers who use them<br />
as long-term cigarette substitutes. An added concern is the safety of the<br />
chemical combinations in various ENDS cartridges, which have not been<br />
evaluated for either short-term or long-term safety. Potential long-term toxicity<br />
would not necessarily preclude short-term use of such products for<br />
smoking cessation, but it is essential to measure the risk associated with exposure<br />
to determine how such products could be used and what information<br />
should be stated on the labels.<br />
2.6 Nicotine addiction as the basis for ENDS marketing<br />
6<br />
ENDS marketing promotes the systems to replace nicotine from tobacco. This<br />
strategy is based on the fact that tobacco use is driven and sustained by nicotine<br />
addiction, as discussed in earlier WHO reports and reports from other
organizations (2–6). In addition to nicotine dependence, the sensory effects<br />
of the product, social and marketing forces and perceptions of harmfulness<br />
and potential benefits should be considered in examining the initiation, patterns<br />
of use and development of addiction.<br />
NRT products facilitate smoking cessation by providing controlled doses of<br />
nicotine to enable gradual withdrawal and reduce dependence. Certain other<br />
drugs, such as bupropion and varenicline, can also be used to treat withdrawal<br />
and dependence and thereby aid smoking cessation efforts. All current NRT<br />
products include guidance on dosing, use and how to minimize the risks for<br />
side-effects specific to that therapy. This guidance is important, because<br />
nicotine is a potent drug, and its health effects are related to dosage and patterns<br />
of use. Furthermore, if NRT products are not used according to the<br />
evidence-based therapeutic guidance, there is no assurance that they will be<br />
effective.<br />
Theoretically, nicotine delivery by electronic vaporization and inhalation of<br />
combination products could be a safe, effective form of treatment for tobacco<br />
addiction. Nevertheless, testing for safety, efficacy and appropriate labelling<br />
are required to evaluate such potential, as described in reports by WHO and<br />
other organizations (5–8).<br />
2.7 ENDS are not nicotine replacement therapy<br />
ENDS should not be confused with NRT products approved for the treatment<br />
of tobacco dependence. Some manufacturers have marketed ENDS as smoking<br />
cessation aids and have communicated claims to the news media that their<br />
products are effective for this use. Furthermore, at least one manufacturer has<br />
claimed that WHO has endorsed its product, stating that WHO’s inclusion of<br />
an NRT device commonly referred to as a nicotine ‘inhaler’ among products<br />
listed as effective smoking cessation aids also includes ENDS. In fact, WHO<br />
has not endorsed this manufacturer’s products and has made that clear in a<br />
formal letter to the sponsor as well as in a press release (9). WHO supports<br />
evidence-based pharmacotherapy when scientific studies demonstrate that<br />
certain applications of products result in predictable outcomes under specified<br />
conditions, and the products have been approved as safe and effective<br />
by major drug regulatory authorities, such as the European Medicines Agency<br />
and the United States Food and Drug Administration.<br />
ENDS and conventional NRT products may differ in design, content and the<br />
mode of delivery of nicotine and other chemicals. The contents and design<br />
features of currently approved NRT products have been fully disclosed, and<br />
their safety and efficacy have been demonstrated under conditions of labelled<br />
use, with evaluations of their nicotine delivery and absorption kinetics. No<br />
currently approved NRT product, including that referred to as an ‘inhaler’,<br />
7
delivers nicotine systemically via the lung. During use of the ‘inhaler’ product,<br />
air is drawn through it, but more than 90% of the nicotine is deposited<br />
and absorbed in the oral cavity, and very little reaches the lung, as confirmed<br />
by positron emission imaging in published studies (10).<br />
2.8 Capacity of ENDS to serve as nicotine replacement therapy<br />
It is possible that at some time in the future ENDS might be developed as<br />
smoking cessation aids. Several smoking cessation experts have argued the<br />
potential benefits of an NRT device in which the treatment is delivered to the<br />
lung (5, 11–13). However, currently, the evidence is insufficient to conclude<br />
that any of the ENDS products is an effective smoking cessation aid or that<br />
they deliver sufficient nicotine for them to be used in smoking cessation. If<br />
ENDS deliver significant amounts of nicotine for lung absorption, concerns<br />
about the safety of lung delivery and the addictive potential of the nicotine<br />
delivered by this route would have to be addressed (5, 12). Claims that<br />
ENDS are smoking cessation aids have not met the standards of evidence<br />
required by scientific organizations and regulatory authorities (e.g. 8, 14).<br />
Thus, at present, there is insufficient evidence that ENDS are safe for human<br />
consumption.<br />
Although ENDS are promoted as smoking cessation aids in some markets,<br />
the manufacturers have not provided evidence-based guidance for their efficacy,<br />
dosing and duration of use, how they should be combined with behavioural<br />
strategies for smoking cessation or guidance for discontinuation.<br />
This information would be required if WHO or national regulatory authorities<br />
were to make even a preliminary evaluation of the safety and effectiveness<br />
of ENDS.<br />
In summary, claims for the effectiveness of ENDS for smoking cessation and<br />
other health effects must be substantiated by rigorous studies of pharmacokinetics,<br />
trials of safety and efficacy and review and approval by major drug<br />
regulatory authorities. The types of data and studies that would be required<br />
include a complete listing of the chemicals used in ENDS products; a listing<br />
and reporting of the concentrations of chemicals delivered to the consumer;<br />
comparisons of the effect of ENDS on smoking cessation with that of approved<br />
NRTs and placebo; and the adverse effects of these products.<br />
2.9 Regulatory status<br />
8<br />
The ENDS products addressed in this recommendation do not require tobacco<br />
for operation but are claimed to deliver nicotine to the consumer. According<br />
to the regulatory schemes of many countries, 1 this would suggest that ENDS<br />
1 Canada, Denmark, the Netherlands, Norway, Turkey and the United States (see Annex 1)
products would appropriately be regulated as combination drugs and medical<br />
devices and therefore could not be marketed until the regulatory authorities<br />
determine that adequate evidence, including data from approved clinical trials,<br />
exists to support approval. Some countries have completely banned the<br />
sale and marketing of ENDS. 2 Some countries and areas allow marketing<br />
within other regulatory frameworks. 3 Internet marketing of ENDS and the<br />
inadequacy and misapplication of import product codes, however, impede<br />
systematic regulation. Regardless of the regulatory approach taken, this report<br />
recommends that claims that ENDS are safer than cigarettes, that they<br />
have health benefits and are effective smoking cessation aids or could be<br />
marketed as cigarette substitutes be prohibited until such claims are substantiated<br />
by sufficient evidence to satisfy their accuracy to independent scientific<br />
organizations and regulatory authorities (e.g. 8, 14).<br />
Some manufacturers have claimed that ENDS can be used legally in environments<br />
where smoking is prohibited. TobReg strongly recommends that<br />
ENDS not be exempted from ‘clean air’ laws, which restrict the places in<br />
which cigarette smoking is allowed, until adequate evidence is provided to<br />
assure regulatory authorities that use of the product will not expose nonusers<br />
to toxic emissions (See Article 8 of the WHO Framework Convention on<br />
Tobacco Control). WHO strongly encourages its Member States to prohibit<br />
manufacturers from marketing electronic cigarettes with claims that WHO<br />
endorses them as legitimate tobacco cessation aids. Furthermore, Member<br />
States should ensure that the manufacturers of these products comply with<br />
all existing regulatory requirements to preclude unsubstantiated claims that<br />
may derail public health efforts in tobacco control.<br />
2.10 Other concerns<br />
The conditions under which marketing of ENDS should be allowed is also a<br />
concern. ENDS may be considered relatively safe and attractive alternatives<br />
to tobacco products by people, including adolescents, who would not otherwise<br />
have used a potentially addictive nicotine product. The product might<br />
therefore ultimately increase tobacco product use.<br />
ENDS might be used to perpetuate smoking by what has been termed ‘dual<br />
use’, that is, sustaining nicotine dependence in environments where smoking<br />
is prohibited. One of the positive consequences of smoking restrictions is the<br />
de-normalization of tobacco product use and the subsequent increase in cessation<br />
rates. ENDS may discourage people from quitting, as users can<br />
maintain their nicotine addiction despite smoking restrictions and resume<br />
smoking where such restrictions are absent.<br />
2 Australia, Brazil, China, Singapore, Thailand and Uruguay (see Annex 1)<br />
3 European Union, New Zealand and the United Kingdom (see Annex 1)<br />
9
Smokers trying to quit may use ENDS in place of effective evidence-based<br />
treatments. If ENDS are not effective NRT products, their use could delay<br />
smoking cessation and contribute to an increased risk for smoking-attributable<br />
disease.<br />
2.11 Conclusions<br />
ENDS products claim to deliver nicotine, an addictive chemical, via the<br />
respiratory system with the purpose of facilitating and perpetuating nicotine<br />
addiction.<br />
The safety and extent of nicotine uptake from ENDS products have not<br />
been established. Although ENDS may cause and sustain addiction, evidence<br />
for potential addiction and the frequency with which addiction<br />
occurs does not currently exist.<br />
Manufacturers have marketed ENDS as smoking cessation aids, and<br />
these products might be effective in this respect; however, scientific evidence<br />
sufficient to establish their actual nicotine dosing capabilities,<br />
their efficacy as smoking cessation aids and safety of use is not yet available.<br />
There is concern that nicotine delivery to the lung might result in stronger<br />
toxicological, physiological and addictive effects, and this concern must<br />
be addressed in scientific studies.<br />
Lung delivery of medications, independent of the effects of nicotine, is<br />
of global importance and must be addressed in scientific studies.<br />
2.12 Recommendations for regulatory policy<br />
10<br />
ENDS products should be regulated as combination drugs and medical<br />
devices and not as tobacco products. Notwithstanding the various marketing<br />
strategies, ENDS might facilitate and perpetuate nicotine<br />
addiction.<br />
If ENDS products are regulated under tobacco control laws, the manufacture,<br />
sale or importation of these products should be subject to<br />
regulation of the contents and labelling (Articles 9–11), prohibition of<br />
public use that might expose others to emissions (Article 8) and restrictions<br />
on advertising, promotion and sponsorship that appeal to adolescents<br />
(Article 13). Countries might consider granting exemption and<br />
concurrent jurisdiction with drug regulatory authorities only if ENDS<br />
products are proven to be safe and effective as smoking cessation aids.<br />
Regulators should weigh the theoretical benefits of ENDS as smoking<br />
cessation aids against those of current NRT products and the risk that the
products will appeal to nonsmokers, that is, the risk that nonsmokers will<br />
be drawn into nicotine addiction.<br />
Manufacturers and retailers must provide evidence to define the appropriate<br />
uses of, exposure to, and safety of ENDS, and regulatory authorities<br />
should confirm the accuracy of this evidence before approving these<br />
products for sale and marketing.<br />
Claims implying health benefits or less harm than cigarettes should be<br />
prohibited, unless the safety of these devices, when used as intended, is<br />
scientifically proven to the satisfaction of regulatory authorities.<br />
Claims that ENDS assist smoking cessation should be prohibited, unless<br />
the efficacy of these devices, when used as intended, is scientifically<br />
proven to the satisfaction of regulatory authorities.<br />
2.13 Recommendations for clinical trials and other research required<br />
for regulatory approval<br />
Research should be conducted on the delivery and absorption of nicotine<br />
from ENDS use, in both the short and the long term, to enable regulators<br />
to establish the dosage and formulation for regulatory approval.<br />
Research should be conducted on the behavioural and physiological<br />
consequences of using ENDS.<br />
The dependence potential (also known as ‘abuse liability’) relative to<br />
cigarettes and NRTs should be studied.<br />
Short- and long-term effects of human exposure should be monitored to<br />
determine potential harm.<br />
Post-marketing studies should be conducted to determine patterns of use,<br />
such as dual use, to monitor adverse effects and to determine the implications<br />
for initiation and cessation at individual and population level.<br />
2.14 References<br />
1. Zezima K. Analysis finds toxic substances in electronic cigarettes. The New<br />
York Times, 22 July 2009. http://www.nytimes.com/2009/07/23/health/policy/<br />
23fda.html.<br />
2. The scientific basis of tobacco product regulation: report of a WHO study<br />
group. Geneva, World Health Organization, 2007 (WHO Technical Report<br />
Series, No. 945).<br />
3. Neuroscience of psychoactive substance use and dependence. Chapter 4 --<br />
Psychopharmacology of dependence for different drug classes. Geneva, World<br />
Health Organization, 2004.<br />
11
12<br />
4. Royal College of Physicians of London. Nicotine addiction in Britain: a report<br />
of the Tobacco Advisory Group of the Royal College of Physicians. London,<br />
Royal College of Physicians of London, 2000.<br />
5. Royal College of Physicians of London. Harm reduction in nicotine addiction;<br />
helping people who can’t quit: A report of the Tobacco Advisory Group of the<br />
Royal College of Physicians. London, Royal College of Physicians of London,<br />
2007.<br />
6. Department of Health and Human Services. Reducing tobacco use: A report<br />
of the Surgeon General. Washington DC, Government Printing Office, 2000.<br />
7. Policy recommendations for smoking cessation and treatment of tobacco<br />
dependence. Geneva, World Health Organization, 2003.<br />
8. Fiore MC et al. Treating tobacco use and dependence: 2008 update. Clinical<br />
practice guideline. Rockville, Maryland U.S. Department of Health and Human<br />
Services, Public Health Service, 2008.<br />
9. Marketers of electronic cigarettes should halt unproved therapy claims. Press<br />
Release. Geneva, World Health Organization, media Centre, 19 September<br />
2008.<br />
http://www.who.int/mediacentre/news/releases/2008/pr34/en/index.html.<br />
10. Bergstrom et al. Regional deposition of inhaled 11 C-nicotine vapor in the<br />
human airway as visualized by positron emission tomography. Clinical<br />
Pharmacology and Therapeutics, 1995, 57: 309–317.<br />
11. Warner KE et al. The emerging market for long-term nicotine maintenance.<br />
Journal of the American Medical Association, 1997, 278:1087–1092.<br />
12. Fant RF et al. Pharmacotherapy for tobacco dependence. Handbook of<br />
Experimental Pharmacology, 2009, 192:487-510.<br />
13. Gray N, Boyle, P. The future of the nicotine-addiction market. Lancet, 2003,<br />
362:844-845.<br />
14. www.treatobacco.net
Annex 1. International regulatory measures for electronic nicotine<br />
delivery systems (ENDS)<br />
Country Regulate as medicinal product Prohibition Source<br />
Western Australia:<br />
Department of Health<br />
and Ageing,<br />
Prohibited as imitation tobacco<br />
Therapeutic Goods<br />
products<br />
Administration<br />
ENDS are prohibited under section October 2008, NDPSC<br />
106 of the Western Australia Tobacco Resolution<br />
Products Control Act 2006, which 2008/54 – 21, http://<br />
states: “106. Products resembling www.tga.gov.au/<br />
tobacco products, packages. A ndpsc/record/<br />
person must not sell any food, toy or rr200810.pdf<br />
other product that is not a tobacco<br />
product but is:<br />
The National Drugs and Poisons Schedule<br />
Committee under the Therapeutic Goods<br />
Administration concluded that nicotine’s<br />
classification as a poison should apply to ENDS,<br />
effectively prohibiting the sale and marketing of<br />
ENDS in all states and territories.<br />
Australia<br />
Therapeutic Goods<br />
Administration<br />
Victoria:<br />
Regulated as a nicotine drug and subject to entry<br />
in the Poisons Code under the Victorian Drugs,<br />
Poisons and Controlled Substances Act 1981<br />
(a) designed to resemble a tobacco<br />
product or a package; or<br />
Substances in the Poisons Code are subject to<br />
regulation under the Victorian Drugs, Poisons and<br />
Controlled Substances Regulations 2006<br />
(Regulation 65):<br />
(b) in packaging that is designed to<br />
A person must not manufacture, sell, supply, resemble a tobacco product or a<br />
purchase or otherwise obtain, possess or use a package.”<br />
listed regulated poison unless the person is<br />
authorized, licensed or permitted under the Act or<br />
these Regulations to do so.”<br />
Penalty: 100 penalty units*<br />
*From 1 July 2009, the value of a penalty unit in<br />
Victoria is AUS$ 116.82.<br />
13
14<br />
ANVISA RDC 41/09<br />
Regulates as tobacco product<br />
http://portal.anvisa.gov.br/wps/portal/anvisa/<br />
home/derivadostabaco<br />
Import, sale or offer for sale prohibited as<br />
imitation tobacco products under RDC<br />
41/09 (August 28th 2009) There shall be<br />
the possibility of registering the product<br />
as medicinal product after the<br />
presentation of all due tests and studies<br />
(article 3rd RDC 41/09).<br />
Article 1 Prohibits marketing,<br />
importing and advertising of any<br />
smoking electronic device<br />
(ENDS), known as electronic<br />
cigarettes, ecigarettes, eciggy,<br />
Ecig among others, especially<br />
those that claim to be<br />
replacement for cigarettes,<br />
cigarillos, cigars, pipes and<br />
similar as alternative in the<br />
treatment of smoking cessation.<br />
Brazil<br />
National Health<br />
Surveillance<br />
Agency<br />
(ANVISA)<br />
Sole Paragraph. Included in the<br />
prohibition in the caput of this<br />
article are any accessories and<br />
refills intended for use in any<br />
smoking electronic device<br />
(ENDS).<br />
Article 2 The admissibility by<br />
ANVISA for the Registration of<br />
Data on any smoking electronic<br />
device (ENDS), especially for<br />
the treatment of smoking<br />
cessation or the replacement of<br />
cigarette, cigar, pipe and<br />
similars in the habit of smoking,<br />
shall depend upon the<br />
submission of toxicological
studies and scientific tests that<br />
prove the specific purposes<br />
alleged.<br />
§ 1. The toxicological studies<br />
and the tests referred to in this<br />
article shall be conducted in<br />
accordance with protocols and<br />
internationally recognized and<br />
accepted scientific methods,<br />
accompanied by the risk<br />
assessment of health damage to<br />
the consumer as well as proof of<br />
non - environmental<br />
contamination with toxic<br />
compounds.<br />
§ 2. All results of toxicological<br />
studies and tests referred to in<br />
this article shall be subject to<br />
technical review and approval<br />
by ANVISA.<br />
§ 3. Even if the registration of the<br />
data of the device (ENDS) shall<br />
be approved in accordance with<br />
the caput of Article 2 it is<br />
forbidden the selling, the<br />
supplying, even as means of<br />
samples, the delivery or the use<br />
in any case, to children or<br />
15
16<br />
adolescent, of any smoking<br />
electronic device (ENDS).<br />
Article 3 The violation of the<br />
provisions under this Resolution<br />
shall subject those responsible<br />
to penalties under the Act 6437<br />
Health Canada, 27 March 2009 http://www.hcsc.gc.ca/ahc-asc/media/advisories-avis/<br />
_2009/2009_53-eng.php<br />
of 20 August 1997.<br />
ENDS, as well as ENDS<br />
cartridges that contain nicotine,<br />
fall within the scope of the Food<br />
and Drugs Act and therefore<br />
require marketing authorization<br />
before they can be imported,<br />
advertised or sold. Currently, no<br />
ENDS products have been<br />
granted marketing<br />
authorization.<br />
Under the Pharmacy & Poisons<br />
Ordinance, ENDS containing<br />
nicotine are classified as poison<br />
products and strictly prohibited.<br />
All products containing nicotine<br />
must be registered with the<br />
department that assesses them<br />
for safety and quality before they<br />
can be sold.<br />
ENDS are classified as<br />
medicinal products that cannot<br />
be sold in the country without<br />
Canada<br />
Health Canada<br />
Hong Kong Legal Information Institute,<br />
Pharmacy and Poisons Ordinance, Cap 138,<br />
sec. 21–24; Pharmacy and Poisons<br />
(Amendment) (No. 4) Regulation 2008, 234;<br />
Poisons List (Amendment) (No. 4) Regulation<br />
2008, 235; http://www.hklii.org/hk/legis/en/ord/<br />
cur/138.txt<br />
Penalty imposed is linked to the<br />
Pharmacy & Poisons Ordinance:<br />
China, Hong<br />
Kong Special<br />
Administrative<br />
Region<br />
“Possession or sale of an unregistered<br />
pharmaceutical product, and possession<br />
of Part I poisons without authority<br />
warrants two-years’ jail and a $100 000<br />
fine.”<br />
Danish Medicines Agency, 9 March 2009 http://<br />
www.dkma.dk/1024/visUKLSArtikel.asp?<br />
artikelID=14819<br />
Denmark<br />
Danish Medicines<br />
Agency
Danish Medicines Agency, 9 October 2008<br />
http://www.dkma.dk/1024/visUKLSArtikel.asp?<br />
artikelID=14250<br />
fulfilling the requirements of<br />
Executive Order No. 1268 of 12<br />
December 2005 on medical<br />
devices and receiving marketing<br />
authorization from the Agency.<br />
To date, the Agency has not<br />
licensed any ENDS; therefore,<br />
any marketing and distribution of<br />
ENDS constitutes a violation of<br />
the provisions of the Danish<br />
Health & Consumer Protection Directorate-<br />
General of the European Commission<br />
Orientation Note 22 May 2008 http://<br />
ec.europa.eu/health/ph_determinants/life_style/<br />
Tobacco/D ocuments/orientation_0508_en.pdf<br />
Medicines Act.<br />
Whether ENDS fall under<br />
Directive 2001/83 on human<br />
medicinal products depends on<br />
whether they can be<br />
characterized as a human<br />
medicine by presentation or by<br />
function. ENDS can be regarded<br />
as a human medicine by<br />
presentation if they are<br />
presented as a remedy for<br />
nicotine addiction. ENDS can be<br />
regarded as a human medicine<br />
by function in so far as they<br />
qualify as “restoring, correcting<br />
or modifying physiological<br />
functions” in a significant<br />
manner.<br />
European<br />
Commission<br />
Health &<br />
Consumer<br />
Protection<br />
Directorate-<br />
General<br />
17
18<br />
Whether ENDS could be<br />
regarded as falling under<br />
Directive 93/42/EEC on medical<br />
devices depends on the claimed<br />
intended use and whether this<br />
intended use has a medical<br />
Ministry of Health, Welfare and Sport, 28<br />
January 2008, http://www.minvws.nl/en/<br />
nieuwsberichten/gmt/2008/klink-seeksconsensus-e-cig.asp<br />
purpose.<br />
Advertising of ENDS products is<br />
banned. In order to market them<br />
legally, manufacturers must<br />
register the products with the<br />
Medicines Evaluation Board.<br />
Cartridges containing nicotine<br />
fall under the requirements of<br />
the Medicines Act and are<br />
regulated by MedSafe. Nicotine<br />
for inhalation can be purchased<br />
from a pharmacist without a<br />
doctor’s prescription. When<br />
selling these medicines,<br />
pharmacists must fulfil special<br />
requirements designed to<br />
ensure that the consumer is<br />
properly informed about the safe<br />
and correct use of the medicine.<br />
Netherlands<br />
Ministry of<br />
Health, Welfare<br />
and Sport<br />
http://www.medsafe.govt.nz<br />
New Zealand<br />
New Zealand<br />
Medicines and<br />
Medical Devices<br />
Safety Authority<br />
(MedSafe)<br />
Regulations concerning prohibition of new<br />
tobacco and nicotine products laid down by<br />
Royal Decree, 13 October 1989, http://<br />
www.regjeringen.no/en/dep/hod/Subjects/The-<br />
Department-of-Public-Health/Norways-<br />
The Norwegian Tobacco Act forbids the<br />
import and sale of new tobacco products<br />
and/or nicotine products, a classification<br />
that encompasses ENDS products.<br />
Norway<br />
Norwegian<br />
Directorate of<br />
Health
National-Strategy-for-Tobacco-Co.html?<br />
id=451948<br />
Highlights of Licensees’ Obligations under the<br />
Smoking (Control of Advertisements and Sale of<br />
Tobacco) Act and its Regulations. Health<br />
Sciences Authority (last updated 29 October<br />
2008)<br />
Import, sale or offer for sale prohibited as<br />
imitation tobacco products under Section<br />
16 of the Smoking (Control of<br />
Advertisements and Sale of Tobacco)<br />
Act. Exemption from prohibition<br />
considered if product is registered as<br />
medicinal product<br />
Medicinal product registration<br />
and product licence required for<br />
the import and sale or supply of<br />
product<br />
Singapore<br />
Tobacco<br />
Regulation Unit,<br />
Health Sciences<br />
Authority<br />
http://www.hsa.gov.sg/publish/hsaportal/en/<br />
health_products_regulation/tobacco/legislation/<br />
Poisons licence required, as the<br />
product contains nicotine, a<br />
substance controlled under the<br />
licensee_obligations.html<br />
Thailand: Public Health Ministry orders study of<br />
e-cigarettes, Non-aligned Movement News<br />
Network, 13 June 2009 (http://<br />
www.namnewsnetwork.org/v2/read.php?<br />
id=51042)<br />
In banning alternative cigarettes,<br />
Thailand does not have to enact a new<br />
law but can use an existing law and<br />
regulation.<br />
Poisons Act<br />
Smoking alternatives are not a<br />
tobacco product, according to<br />
the law, if they are not produced<br />
from Nicotiana tabacum. As<br />
such, they are classified as a<br />
drug containing nicotine, which<br />
is an alkaloid. Therefore, ENDS<br />
manufacturers must apply to the<br />
Food and Drug Administration<br />
for import and sale in the<br />
country. Before giving<br />
permission the Food and Drug<br />
Administration would have to<br />
examine all scientific evidence<br />
about the drug.<br />
Thailand<br />
Food and Drug<br />
Administration<br />
Hürriyet Daily News, 3 January 2008, http://<br />
arama.hurriyet.com.tr/arsivnews.aspx?<br />
id=-621407<br />
In 2008, it was reported that the sale of<br />
ENDS was suspended by the Ministry of<br />
Health. The Advertisement Board under<br />
the Ministry of Industry and Trade<br />
Turkey<br />
Turkish Ministry<br />
of Health<br />
19
20<br />
Hürriyet Daily News, 17 January 2008, http://<br />
arama.hurriyet.com.tr/arsivnews.aspx?<br />
id=-622303<br />
followed suit and banned public<br />
advertisement of ENDS, noting that the<br />
Ministry of Health had not approved use<br />
of the products.<br />
ENDS manufacturers are prohibited from<br />
selling these products under general<br />
product safety principles, unless the<br />
packaging bears the appropriate safety<br />
warnings in terms of the Chemicals<br />
(Hazard Information and Packaging for<br />
Supply) Regulations 2009.<br />
If ENDS are marketed as a<br />
smoking cessation aid, they are<br />
licensable as a medicine by the<br />
Medicines and Healthcare<br />
Products Regulatory Agency.<br />
As a smoking alternative,<br />
however, the use of ENDS is<br />
unrestricted. Conversely,<br />
products that contain nicotine at<br />
safe levels but which are<br />
presented as a replacement for<br />
or alternative to tobacco<br />
products, in circumstances<br />
where smoking is not permitted,<br />
such as air travel, the theatre or<br />
United Kingdom<br />
Medicines and<br />
Healthcare<br />
Products<br />
Regulatory<br />
Agency<br />
As most manufacturers do not have the<br />
appropriate safety warnings (e.g.<br />
appropriate packaging, ‘highly toxic’<br />
labels, tactile warnings, child-resistant<br />
fastenings), these products would, in<br />
theory, be prohibited. They are, however,<br />
currently marketed and distributed in the<br />
United Kingdom.<br />
FDA considers ways to short-circuit electronic<br />
cigarettes. USA Today, 22 July 2009 (http://<br />
www.usatoday.com/news/health/2009-07-22electroniccigarette_N.htm)<br />
(last updated 29 July<br />
2009)<br />
FDA has seized about 50 shipments of<br />
ENDS products and is reviewing the new<br />
tobacco law that is the basis of the<br />
Agency’s jurisdiction to regulate tobacco<br />
products; the Agency is considering a<br />
range of enforcement actions, including<br />
recalls and criminal sanctions.<br />
cinema, are not licensable.<br />
FDA considers ENDS to be<br />
combination drug and medical<br />
devices, and marketing of these<br />
products is illegal without<br />
regulatory approval.<br />
United States of<br />
America<br />
United States<br />
Food and Drug<br />
Administration<br />
(FDA)<br />
Federal caution on electronic cigarettes. The<br />
Washington Post, 23 July 2009 (http://<br />
www.washingtonpost.com/wp-dyn/content/<br />
article/2009/07/22/AR2009072203558.html).<br />
A 2009 FDA study found that several<br />
cartridges contained detectable levels of<br />
FDA has announced that a claim<br />
or representation for smoking<br />
cessation is not the only element<br />
it evaluates in making these
Analysis finds toxic substances in electronic<br />
cigarettes. The New York Times, 23 July 2009<br />
(http://www.nytimes.com/2009/07/23/health/<br />
policy/23fda.html).<br />
FDA: Electronic cigarettes contain toxic<br />
chemicals. The Associated Press, 22 July 2009<br />
(http://www.google.com/hostednews/ap/article/<br />
ALeqM5iFxte-<br />
Xw6qPRQqUJmEnNTkDqGoJQD99JOJA00).<br />
nitrosamines, which are carcinogens,<br />
and diethlyene glycol, a common<br />
ingredient of antifreeze that is toxic to<br />
humans. In addition, the study showed<br />
that the levels of nicotine vary even in<br />
cartridges with labels that claim to have<br />
the same amount, including those<br />
labelled as not containing nicotine.<br />
determinations. It also focuses<br />
on the product’s intended uses,<br />
on whether they are intended to<br />
affect the body’s structures and<br />
functions and/or to treat,<br />
mitigate or prevent disease (e.g.<br />
nicotine addiction).<br />
FDA has reviewed electronic<br />
cigarettes, cigars and pipes and<br />
their components and classified<br />
them as drug–device<br />
combinations under section 503<br />
(g)(1) of the Federal Food, Drug,<br />
and Cosmetic Act (the Act) (21<br />
USC § 353(g)(1)) with their<br />
‘drug’ uses, as defined in section<br />
201(g) of the Act (21 USC § 321<br />
(g)), as the primary mode of<br />
action, which are intended to<br />
affect the body’s structures and<br />
functions and, in some cases, to<br />
treat or prevent withdrawal<br />
symptoms of nicotine addiction.<br />
Uruguay Sale in Uruguay is banned via a decree<br />
issued in November 2009.<br />
21
3. Report on setting regulatory limits<br />
for carcinogens in smokeless<br />
tobacco<br />
3.1 Background<br />
The WHO Study Group on Tobacco Product Regulation (TobReg) has prepared<br />
a series of reports to provide a scientific foundation for tobacco product<br />
regulation (1, 2) to support the provisions of Article 9 of the WHO Framework<br />
Convention on Tobacco Control. The reports identify approaches for regulating<br />
cigarettes, including mandated reductions in the concentrations of<br />
toxicants present in smoke. The most recent report suggests that reducing the<br />
concentrations of toxicants present in smokeless tobacco products would be<br />
a logical scientific extension of this regulatory strategy (2).<br />
Smokeless tobacco products are used widely in Asia (particularly South-East<br />
Asia), Africa, North America and parts of Europe (3). There are well documented<br />
differences in the contents and formulations of smokeless tobacco<br />
products used in different countries, and there are scientifically documented<br />
differences in the adverse health outcomes resulting from use of these different<br />
products (3). Smokeless tobacco has been causally associated with<br />
oropharyngeal cancer, pancreatic cancer and heart disease (3, 4); but these<br />
risks vary dramatically by geographic location and composition of the smokeless<br />
tobacco product used, with very high risks evident for products used in<br />
Africa and the Indian subcontinent and lower risks occurring in studies conducted<br />
in the U.S. and Scandinavian countries, particularly in Sweden where<br />
low nitrosamine snuff has been in widespread use (3).<br />
The content of smokeless tobacco is substantially less complex than the<br />
emissions of combusted tobacco products. Smokeless tobacco contains fewer<br />
carcinogens, but some formulations have substantial amounts of some carcinogens<br />
common to cigarette smoke emissions (3–6). Differences of several<br />
orders of magnitude in the concentrations of carcinogens have been found<br />
between products with the lowest levels, which are most commonly marketed<br />
in the developed world, and those produced in ‘cottage’ industries in Asia<br />
and Africa. The differences among manufactured smokeless tobacco products<br />
used in different regions are more modest, but even within the same<br />
region there are substantial differences in products (3). Differences in the<br />
23
content and formulation of the smokeless tobacco products used in different<br />
geographical areas might reasonably explain the different health outcomes<br />
observed with their use. The disease outcomes indicate a public health benefit<br />
of regulation. Regulatory lowering of the concentrations of carcinogens in<br />
smokeless tobacco products might reduce the numbers of cancers resulting<br />
from their use.<br />
Differences in the concentrations of two groups of powerful carcinogens in<br />
smokeless tobacco, tobacco-specific N-nitrosamines (TSNA) and polycyclic<br />
aromatic hydrocarbons (PAH), might explain the diverse cancer risks seen<br />
with use of these products in different regions. The carcinogenic potency of<br />
these compounds and the possibility for substantially lowering their concentrations<br />
in smokeless tobacco with existing techniques make these carcinogens<br />
priorities for regulatory consideration.<br />
At a meeting of TobReg held in Durban, South Africa, in November 2008,<br />
consideration was given to regulatory approaches by which the concentrations<br />
of carcinogens in smokeless tobacco could be lowered. After reviewing<br />
the evidence, the Study Group concluded that it is both desirable and feasible<br />
to regulate smokeless tobacco by setting regulatory limits on the concentrations<br />
of selected carcinogens. It further recommended that regulation begin<br />
with PAH and TSNA. This TobReg report presents the scientific evidence<br />
for regulating smokeless tobacco products and makes recommendations for<br />
the initial regulatory levels.<br />
3.2 Carcinogens present in smokeless tobacco<br />
24<br />
Smokeless tobacco is taken orally or nasally without burning the product at<br />
the time of use. Oral smokeless tobacco products are placed in the mouth,<br />
cheek or lip and sucked (‘dipped’) or chewed. Tobacco pastes or powders are<br />
used in a similar manner and placed on the gums and teeth. Fine tobacco<br />
mixtures may be inhaled nasally and the contents absorbed in the nasal<br />
passages.<br />
Smokeless tobacco has been classified by the International Agency for Research<br />
on Cancer (IARC) as ‘carcinogenic to humans’ (Group 1) (3). There<br />
are, however, many forms of smokeless tobacco, which differ considerably<br />
in their composition and carcinogenic potential. Available information indicates<br />
the presence of 28 potential or known carcinogens (5). The list below<br />
contains only those identified in smokeless tobacco that meet the criteria for<br />
inclusion as IARC group 1 carcinogens (‘sufficient’ evidence of carcinogenicity<br />
in humans):<br />
benzo[a]pyrene<br />
formaldehyde
N-nitrosonornicotine (NNN)<br />
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)<br />
arsenic<br />
nickel compounds<br />
polonium-210<br />
uranium-235<br />
uranium-238<br />
beryllium<br />
cadmium<br />
chromium<br />
3.3 Tobacco-specific nitrosamines and polycyclic aromatic<br />
hydrocarbons<br />
Tobacco-specific nitrosamines (TSNA) are formed from tobacco alkaloids<br />
and nitrosating agents, such as nitrite. They are found only in tobacco<br />
products. Seven TSNA have been detected in smokeless tobacco: NNN,<br />
N-nitrosoanabasine, N-nitrosoanatabine, NNK, 4-(methylnitrosamino)-1-<br />
(3-pyridyl)-1-butanol, 1-(methylnitrosamino)-1-(3-pyridyl)-4-butanol and 4-<br />
(N-nitrosomethylamino)-4-(3-pyridyl)butyric acid. Of these, NNN and NNK<br />
are considered the most important because of the levels at which they occur<br />
in smokeless tobacco and their carcinogenic potency. Procedures exist for<br />
dramatically limiting the formation of TSNA in smokeless tobacco, including<br />
those used by some manufacturers of smokeless tobaccos sold in Sweden<br />
(7) and the manufacturer of the Russian nass (8). A comprehensive review<br />
of the techniques available was prepared by O’Connor and colleagues (9).<br />
The procedures include a short ageing process, use of tobacco with a low<br />
nitrate content, a pasteurization-like process that destroys bacteria implicated<br />
in the formation of nitrosamines and changes in the methods for curing tobacco.<br />
Refrigeration of the product also helps limit the formation of nitrosamines<br />
during storage.<br />
Polycyclic aromatic hydrocarbons (PAH) are carcinogenic constituents<br />
of smokeless tobacco (3, 5, 10–12), which are products of incomplete combustion<br />
of organic matter. They are not found in raw tobacco leaf, except in<br />
areas where there are high levels due to ambient air pollution. The commonest<br />
source of PAH in smokeless tobacco is smoke from wood (or other organic<br />
matter) burnt during tobacco curing; therefore PAH can be viewed as<br />
unnecessary contaminants of smokeless tobacco that should not be present,<br />
rather than intrinsic constituents which should be minimized.<br />
25
3.4 Differences in carcinogens present in smokeless tobacco by<br />
region<br />
26<br />
A working group convened by IARC (3) reviewed studies on the concentrations<br />
of TSNA in a variety of smokeless tobacco products in different regions<br />
(Table 1). The measurements were made on products sold during different<br />
decades, with different methods and reported by different laboratories; however,<br />
even with these sources of variation, the levels of TSNA clearly varied<br />
considerably among products sold in different parts of the world. Relatively<br />
low levels of NNN and NNK were reported in products described as ‘low-<br />
TSNA smokeless tobacco’, for instance in South Africa and Sweden, and in<br />
some products from Thailand and Uzbekistan. Even some of the products<br />
used in Sweden have been reported to have relatively high levels of NNN.<br />
Generally, moist snuff products used in Europe and the United States contain<br />
lower levels of TSNA than products on the Indian market or those imported<br />
from South Asia to the United Kingdom (3, 5, 11, 12). A wide range of concentrations<br />
is reported, however, even in products on the market in Europe<br />
and the United States, ranging from undetectable to levels comparable to<br />
those of the more toxic products available on Asian markets. The IARC review<br />
makes it clear that, while the products used in developed countries<br />
generally have lower TSNA levels, some have high TSNA levels. Conversely,<br />
some products with relatively low levels of TSNA are available in<br />
almost all countries in which a substantial number of products have been<br />
examined, even in those countries where most products have high TSNA<br />
levels and where there is a high burden of disease due to smokeless tobacco<br />
use. The concentrations of NNN and NNK in Sudanese toombak are extremely<br />
high: the concentration of NNN was reported to be 141–3085 μg/g<br />
of tobacco dry weight and that of NNK was 188–7870 μg/g of tobacco dry<br />
weight (13–15).<br />
The moist snuff (snus) currently manufactured, marketed and used in Sweden<br />
has been well studied and is produced to a standard (7) that results in a lower<br />
nitrosamine content. In the United States, there are both ‘traditional’ products,<br />
which have relatively high concentrations of TSNA, and newer products,<br />
which have levels closer to those of the Swedish product (12).<br />
In Asia, especially India, and in other developing countries, there are many<br />
tobacco mixtures, which are administered in various ways and often prepared<br />
and marketed by individuals or small manufacturers (cottage industry).<br />
Differences in the composition of the products on these markets are<br />
therefore difficult to define. Certain products have been described by IARC<br />
(Table 1) (3).
Table 1<br />
Concentrations of tobacco-specific N-nitrosamines in selected smokeless tobacco<br />
products (μg/g dry weight of tobacco)<br />
Country Type of<br />
product<br />
NNK NNN NAB NAT<br />
Belgium Chewing 0.13 7.38 970 (includes<br />
tobacco<br />
NAB)<br />
Canada Moist snuff 3.2–5.80 50.4–79.1 4–4.8 152.0–170.0<br />
Canada Chewing<br />
tobacco<br />
0.24 2.09 0.1 1.58<br />
Germany Chewing 0.03–0.3 1.42–2.30 0.03–0.05 0.33–3.7 (upper<br />
tobacco<br />
value includes<br />
NAB)<br />
Germany Dry snuff 0.58–6.43 2.93–18.75 NR 1.03–7.83<br />
India Chewing 0.13–0.6 0.47–0.85 0.03–0.07 0.3–0.5 (upper<br />
tobacco<br />
value includes<br />
NAB)<br />
India Zarda 0.22–24.1 0.4–79.0 NR 0.78–99.1<br />
(includes NAB)<br />
India Mishri 0.294–1.1 0.3–6.995 NR 0.488–14.15<br />
India Khiwam 0.1–1.03 2.5–8.95 NR 1.83–10.36<br />
India Zarda 0.22–24.1 0.4–79 NR 0.78–99.1<br />
India Khaini 0.11–5.29 25.8–40 1.24–2.48 0.66–18.8<br />
South Africa Low-TSNA<br />
moist snuff<br />
0.27–0.29 1.05–2.07 0.09–0.11<br />
Sudan Toombak 188–7870 141–3080 139–2370 20–290<br />
Sweden Moist snuff 0.19–2.95 1.12–154 0.04–1.7 0.9–21.4<br />
Thailand Chewing<br />
tobacco<br />
0.1 0.5 NR 0.5<br />
United Moist snuff 0.4–13.0 1.1–52.0 0.086 2.0–6.5 (upper<br />
Kingdom<br />
value includes<br />
NAB)<br />
United Chewing 0.3 0.9 NR 1.5 (upper value<br />
Kingdom tobacco<br />
includes NAB)<br />
United<br />
Kingdom<br />
Dry snuff 0.58–4.3 2.39–16.0 NR 1.03–7.83<br />
United States Moist snuff ND–18.0 ND–147.0 0.02–10.67 0.24–339.0<br />
United States Chewing<br />
tobacco<br />
ND–1.1 0.67–6.5 0.02–0.14 0.67–12,4<br />
United States Dry snuff 0.88–84.4 9.37–116.1 0.52–1.53 11.2–238.8<br />
(upper value<br />
includes NAB)<br />
Uzbekistan Naswar 0.02–0.13 0.12–0.52 0.008–0.03 0.032–0.3<br />
From reference 2<br />
NAB, N-nitrosoanabasine; NAT, N-nitrosoanatabine; ND, not detected; NNK,<br />
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; NNN, N-nitrosonornicotine; NR, not reported<br />
27
This report is concerned with the concentrations of TSNA and benzo[a]<br />
pyrene found in products currently being marketed, rather than the historical<br />
ranges important for disease causation. The concentrations in products obtained<br />
more recently are shown in tables 2 and 3. A wide range of concentrations<br />
was found for both TSNA and benzo[a]pyrene in various products,<br />
and substantial differences were found in the levels in new and traditional<br />
smokeless tobacco products.<br />
Table 2<br />
Concentrations of tobacco-specific nitrosamines (TSNA) and benzo[a]pyrene in<br />
smokeless tobacco products purchased in the United Kingdom and elsewhere<br />
Product TSNA a (μg/g dry<br />
weight)<br />
Products purchased in the United Kingdom<br />
Guthka products<br />
Manikchard 0.289 0.4<br />
Tulsi mix 1.436 1.28<br />
Zarda products<br />
Hakim Pury 29.705 0.32<br />
Dalal Misti Zarda 1.574 8.89<br />
Baba Zarda (GP) 0.716 2.04<br />
Tooth-cleaning powder: A. Quardir Gull 5.117 5.98<br />
Dried tobacco leaf 0.223 0.11<br />
Products purchased outside the United Kingdom<br />
Baba 120 (India) 2.361 2.83<br />
Snus (Sweden) 0.478 1.99<br />
Ariva (United States) ND 0.4<br />
Copenhagen (United States) 3.509 19.33<br />
Benzo[a]pyrene (ng/g<br />
dry weight)<br />
From reference 11<br />
aN-nitrosoanabasine, N-nitrosoanatabine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone ND,<br />
not detected<br />
28<br />
PAH originate primarily from fire-curing of tobacco and are therefore avoidable<br />
contaminants of smokeless tobacco. They are generally locally acting<br />
carcinogens and have been extensively evaluated for carcinogenicity in<br />
mouse skin models (16). The carcinogenicity of PAH varies considerably<br />
because of differences in relative molecular mass and biochemical properties.<br />
As PAH always occur as complex mixtures, the concentration of benzo[a]<br />
pyrene is commonly used as a proxy for that of PAH.
Table 3<br />
Concentrations of tobacco-specific nitrosamines (TSNA) and benzo[a]pyrene in<br />
smokeless tobacco products sold in the United States<br />
Product NNN + NNK Benzo[a]pyrene<br />
No. of<br />
samples<br />
μg/g dry<br />
weight<br />
No. of<br />
samples<br />
ng/g dry<br />
weight<br />
Taboka, Marlboro Snus, Camel<br />
Snus<br />
8 1.04–1.82<br />
Taboka, Marlboro Snus, Camel<br />
Snus, Skoal Dry<br />
11 ND–2.1<br />
Camel Snus Original 1 10.5<br />
General Snus 1 2.3 1 ND<br />
Skoal Dry 3 2.81–5.61<br />
Mint Marlboro Snus 1 3.50<br />
Traditional smokeless tobacco 4 4.86–8.27 4 30.1–57.3<br />
United States moist snuff 39 5.5–98.6<br />
From reference 12<br />
NNN, N-nitrosonornicotine; NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; ND, not detected<br />
The concentration of benzo[a]pyrene in natural tobacco and snuff in the<br />
United States was < 0.1–90 ng/g of tobacco (unspecified as to wet or dry<br />
weight) (5). Products in the United Kingdom and some other countries<br />
(Table 2) were found to contain 0.11–19.33 ng/g dry weight, with the lowest<br />
levels in tobacco leaf and the highest in Copenhagen smokeless tobacco in<br />
the United States. A recent study of smokeless tobacco products available<br />
in the United States (Table 3) showed that General Snus and newer testmarketed<br />
brands had lower concentrations of PAH than a selected set of other<br />
brands, including Copenhagen (12). The other brands had on average 12 times<br />
more acenaphthylene, 71 times more phenanthrene, more than 300 times<br />
more anthracene, 40 times more fluoranthene, 50 times more pyrene, 14 times<br />
more benzofluoranthenes and 12 times more benzo[a]pyrene than the newer<br />
products.<br />
The observations that smokeless tobacco products can be manufactured with<br />
relatively low levels of TSNA and benzo[a]pyrene and that products with<br />
high levels of these carcinogens remain on the market suggest that the composition<br />
and toxicity of smokeless tobacco will continue to vary markedly in<br />
the absence of regulatory control. The availability of techniques to produce<br />
products low in TSNA and benzo[a]pyrene and the existence of voluntary<br />
programmes intended to reduce the concentrations of those carcinogens has<br />
not resulted in uniformly low TSNA levels in most products. These realities<br />
suggest that regulatory control could reduce the levels of carcinogens in<br />
smokeless tobacco.<br />
29
3.5 Targets for regulation<br />
In most parts of the world where smokeless tobacco is widely consumed, the<br />
products used include both those sold by large manufacturers and those produced<br />
by individuals and in cottage industries. The products most amenable<br />
for initial regulatory control are those produced by large manufacturers.<br />
TobReg recognizes that these companies represent only a fraction of the<br />
market and do not produce the products with the highest carcinogen content.<br />
Nevertheless, we recommend that initial regulatory efforts be focused on<br />
large manufacturers and importers of smokeless tobacco, who can change<br />
products rapidly. The more complex problem of limiting the levels of carcinogens<br />
in products produced by cottage industries should not be used as an<br />
excuse to allow higher levels than needed in manufactured products. Rather,<br />
companion programmes to educate cottage industry producers and to design<br />
improved production processes for small producers should be set up. In particular,<br />
attention should be given to the use of tobacco with a low nitrate<br />
content, use of a pasteurization process that destroys the bacteria implicated<br />
in the formation of nitrosamines, avoidance of wood-smoke curing and use<br />
of refrigeration during storage before sale. These techniques, while not yet<br />
available in poor villages, may become available in coming decades.<br />
The inability of cottage industries to produce smokeless tobacco with lower<br />
concentrations of toxicants should not be used as a justification on the part<br />
of developing countries for tolerating the presence of tobacco products with<br />
higher levels of carcinogens in the manufactured segment of the market, as<br />
this segment can readily reduce levels. The levels of TSNA and PAH shown<br />
in tables 1–3 clearly show that manufacturers in both developed and developing<br />
countries can make smokeless tobacco products with low concentrations<br />
of TSNA and benzo[a]pyrene.<br />
Lower carcinogen levels may be more easily achieved in wealthy countries,<br />
but TobReg considers that higher toxicant levels in manufactured products<br />
should not be accepted in countries with fewer economic resources.<br />
3.6 Selection of metric for regulation<br />
30<br />
Although the users of cigarettes adjust their pattern of puffing to achieve the<br />
desired dose of nicotine, the delivery of substances from smokeless tobacco<br />
is influenced mainly by the product itself rather than the user. Users can adjust<br />
the quantity of smokeless tobacco they use, the placement of the product and<br />
the duration of use, but the delivery of toxicants is largely a function of the<br />
product composition and formulation. The levels of toxicants in smokeless<br />
tobacco could be normalized by a variety of approaches, each of which has<br />
its advantages and limitations.
Per typical dose used: One advantage of this approach is that it might<br />
approximate the amount of toxicant presented to a user with each use.<br />
The limitations include the fact that there is substantial variation in the<br />
amount actually used by individuals, limited data on the quantities actually<br />
used per use of many products, and no accepted international<br />
standard for typical dose used. The advantage of approximating the dose<br />
presented to the user is diminished by the reality that the exposure of<br />
individuals per dose is also a function of the time they hold the dose in<br />
their mouths and by other actions that may be taken to increase delivery.<br />
This approach would be complex to administer, as it would require a<br />
different standard for each formulation of smokeless tobacco, and perhaps<br />
for different brands or groupings within the same formulation, on<br />
the basis of differences in patterns of use, making comparisons of products<br />
problematic.<br />
Per gram as sold: The advantage of this approach is that the product<br />
tested would approximate the product acquired by the user. Thus, the<br />
sample tested would be what the user actually encounters. Furthermore,<br />
the same quantity of product would be measured in comparisons of different<br />
products. Different products have different moisture levels, however,<br />
and the moisture level in the same product might vary with the<br />
humidity of the environment in which it is stored. Therefore, samples of<br />
smokeless tobacco would have to be stored at a standardized humidity<br />
before measurement, as is done for cigarettes. The question that arises is<br />
whether the measure actually reflects the product available for purchase.<br />
Also, manufacturers might vary the moisture in their products to achieve<br />
the desired regulatory level.<br />
Per gram dry weight: This approach has the advantages of standardization<br />
to the same quantity of product for comparisons and avoiding the<br />
variation created by differences in moisture content among products and<br />
by differences due to the humidity of the storage environment. One concern<br />
is that manufacturers might add non-tobacco components to smokeless<br />
tobacco in order to meet the standard. The levels proposed by<br />
TobReg are not intended to result in small incremental changes in the<br />
product, however, and the addition of small amounts of non-tobacco<br />
material would not reduce the concentrations of nitrosamines by the orders<br />
of magnitude necessary to meet the regulatory standard for products<br />
with the high levels found in Asia and Africa. Additionally, measurement<br />
per gram dry weight is a long-accepted method of standardizing measurements<br />
of smokeless tobacco constituents, and there are abundant data<br />
in the literature on the levels of various toxicants in different smokeless<br />
tobacco products from different regions based on this metric.<br />
31
Per gram nicotine: This approach is similar to that used by TobReg in<br />
the proposed standards for cigarette emissions. It presupposes that users<br />
adjust their use patterns to differences in nicotine levels and that normalizing<br />
the amount of nicotine will remove the differences in formulation<br />
intended to exploit this compensatory behaviour. Compensatory<br />
behaviour is somewhat less of a concern with smokeless tobacco, as the<br />
principal form of compensation is use of increased amounts, as opposed<br />
to cigarettes, with which the intake of nicotine is increased largely by<br />
altering puffing behaviour. One concern is that manufacturers might<br />
simply add nicotine to the product to meet the standards. An unresolved<br />
question with respect to this approach is whether the normalization<br />
should be to total nicotine or to nicotine in the free (unprotonated) form.<br />
While the free form of nicotine is the form of greatest concern for blood<br />
nicotine levels, it is possible to alter the free nicotine levels independently<br />
of the total nicotine levels, in ways that might result in dramatic changes<br />
in free nicotine levels when the product is mixed with saliva. Manufacturers<br />
might be able to increase the amount of nicotine in a product but<br />
reduce the pH, thus reducing the fraction in the free form. This approach<br />
would be appropriate only if the regulation also included a standard for<br />
nicotine.<br />
Per gram of residual weight: This approach normalizes measurements<br />
to the weight of product remaining after all of the extractable components<br />
have been extracted. It is being evaluated by the United States National<br />
Cancer Institute for use in normalizing measurements of smokeless tobacco<br />
toxicants. Few data are available, however, on use of this approach,<br />
and it would be premature to recommend it.<br />
TobReg considered each of the above approaches and, after weighing their<br />
strengths and limitations, recommended that the amount of toxicant be normalized<br />
per gram of dry weight of smokeless tobacco. This metric is intended<br />
to be a product performance standard rather than a measure of human exposure<br />
to toxicants. It is in accordance with currently established laboratory<br />
practice and may be modified as that practice is improved.<br />
3.7 Selection of achievable levels for tobacco-specific Nnitrosamines<br />
and benzo[a]pyrene in smokeless tobacco<br />
32<br />
The criterion used in selecting a level of TSNA for regulation was to identify<br />
the low concentrations that have been achieved in existing products, as reported<br />
in the literature. That literature includes measurements made over<br />
several decades and with various methods in different laboratories, and is for<br />
products currently being marketed as well as older products. Some of the<br />
differences in reported levels may be due to use of different methods by
different laboratories. In order to identify the concentrations that could be<br />
achieved with existing techniques in a range of current products, TobReg<br />
concentrated on recent studies in two well-respected laboratories (12, 17)<br />
(Table 3).<br />
Examination of the concentrations in current products, including products<br />
stated to have low TSNA levels (12), showed that a number of products have<br />
concentrations of NNN and NNK < 2 μg/g dry weight. Equally important,<br />
the results show that the concentrations in other traditional smokeless tobacco<br />
products on the market substantially exceed this value. It was TobReg’s<br />
judgement that concentrations < 2 μg/g dry weight of tobacco could be<br />
achieved for NNN and NNK in most major manufacturing markets. While<br />
the moist snuff products on the United States market do not include any with<br />
a combined concentration of NNN and NNK < 2 μg/g dry weight, the concentration<br />
in low-TSNA moist snuff sold in South Africa and other countries<br />
(see Table 1) is lower than this level. The lower levels of TSNA reported in<br />
products sold in most developing countries (Table 1) include concentrations<br />
that are below the recommended upper limit, suggesting that achieving that<br />
limit is not beyond the capability of those manufacturers who are currently<br />
marketing in Africa and Asia.<br />
The concentrations of TSNA increase in smokeless tobacco during storage<br />
at room temperature due to microbial action. Therefore, TobReg recommends<br />
that smokeless tobacco be stored and sold under conditions of refrigeration<br />
whenever possible and be attributed an expiration or sell-by date to minimize<br />
any increase in the levels of TSNA between manufacture and sale.<br />
The regulatory limit recommended for TSNA is a maximal concentration of:<br />
NNN plus NNK: 2 μg/g dry weight of tobacco.<br />
When considering a recommended concentration of benzo[a]pyrene, TobReg<br />
investigated whether there was justification for any benzo[a]pyrene in<br />
smokeless tobacco, as it is a product of combustion, and combustion does not<br />
occur in smokeless tobacco use. The sources of benzo[a]pyrene in smokeless<br />
tobacco are curing of tobacco with wood smoke (exposure to benzo[a]pyrene<br />
as a combustion product of wood) and, to some extent, high ambient general<br />
air pollution (3). Both sources are avoidable in the production of manufactured<br />
smokeless tobacco. Examination of tables 2 and 3 shows that low<br />
concentrations of benzo[a]pyrene are present (often below the threshold for<br />
detection) in most of the newer smokeless tobacco products and in some<br />
traditional products. The tables show higher levels in other manufactured<br />
products, indicating that there is an opportunity to reduce the benzo[a]pyrene<br />
levels through regulation.<br />
33
As benzo[a]pyrene is an avoidable contaminant, which is introduced into<br />
smokeless tobacco during tobacco growth and curing, TobReg recommends<br />
that the concentration be based on the lower level of detection that can be<br />
achieved by most laboratories in which tobacco constituents are measured.<br />
While sophisticated methods can detect extremely low levels of this toxicant,<br />
most can detect concentrations > 4.5 ng/g dry weight of tobacco with readily<br />
available techniques, even when testing for PAH in general rather than using<br />
methods specific to benzo[a]pyrene. TobReg therefore recommends a regulatory<br />
level of < 5 ng/g dry weight of tobacco for benzo[a]pyrene. As lower<br />
detection limits for benzo[a]pyrene become technically feasible, TobReg<br />
recommends that this recommendation be revised.<br />
The regulatory limit recommended for benzo[a]pyrene is a maximal concentration<br />
of:<br />
benzo[a]pyrene: 5 ng/g dry weight of tobacco.<br />
3.8 Regulatory considerations and communication of regulatory<br />
values and testing results to the public<br />
34<br />
The purpose of this recommendation is to reduce the concentrations of carcinogens<br />
currently present in many smokeless tobacco products to the low<br />
levels readily achievable with existing techniques through altered manufacturing<br />
practices. This recommendation is not intended to address questions<br />
of reduction in risk or harm that may occur when shifting from one tobacco<br />
product to another, or the question of whether use of smokeless tobacco<br />
should be recommended as a harm reduction strategy to current cigarette<br />
smokers.<br />
The mandated limits on carcinogen concentrations recommended in this report<br />
constitute a first step towards regulation of smokeless tobacco products<br />
by setting performance standards. The immediate next steps would include<br />
methods to address the carcinogen levels present in products produced by<br />
cottage industries, which might initially have to focus more on education and<br />
technology transfer than on regulatory levels.<br />
Mandating levels and disallowing brands with higher levels from the market<br />
does not imply that the remaining brands are safe or less hazardous than the<br />
brands that are removed. It also does not represent government recognition<br />
of the safety of the products that remain on the market. The proposed strategy<br />
for limiting carcinogens is based on sound precautionary approaches, similar<br />
to those used for other consumer products. As an essential part of this proposal,<br />
regulators must assume responsibility to ensure that consumers are not<br />
told directly or indirectly or led to believe that smokeless tobacco products<br />
that meet the carcinogen limits established pursuant to this proposal are less
hazardous than similar products, have been approved by the government or<br />
meet government-established health or safety standards. In particular, ranking<br />
of brands by the metric proposed in this report could be interpreted by<br />
users as reliable differences in the probable exposure or harm that will result<br />
from using different smokeless tobacco brands. Communicating such rankings<br />
to the consumer or allowing them to be communicated directly or<br />
indirectly is likely to influence user behaviour in ways that will cause harm,<br />
similar to that currently caused by communicating the ratings of the International<br />
Organization for Standardization (ISO) for tar, nicotine and carbon<br />
monoxide to cigarette smokers.<br />
The proposed strategy must be applied in ways that will prevent the new<br />
standards from being used as marketing tools to misinform consumers. Unsubstantiated<br />
claims for health or exposure on the basis of the proposed testing<br />
should be prohibited, as a companion condition essential to responsible implementation<br />
of this regulatory strategy.<br />
Measurements of carcinogen levels by brand and all the costs associated with<br />
testing and reporting are expected to be the responsibility of tobacco product<br />
manufacturers. The results should be reported to the regulatory authority, and<br />
a sample of the results should be verified by an independent laboratory. Alternatively,<br />
some regulators may wish to conduct the testing themselves, with<br />
funding from taxation or licensing of tobacco products.<br />
Given the existing scientific limitations, regulatory authorities have an obligation<br />
to ensure that the public is not misled by the results of the recommended<br />
testing and regulatory strategy. TobReg recommends that any<br />
regulatory approach specifically prohibit use of the results of the proposed<br />
testing in marketing or other communications with the consuming public,<br />
including product labelling. TobReg also recommends that manufacturers be<br />
prohibited from making statements that a brand has met government regulatory<br />
standards or from publicizing the relative ranking of brands by testing<br />
level. Because information is often transmitted to tobacco users through the<br />
kinds of news stories that accompany the implementation of new regulations,<br />
it is a responsibility of the regulatory structure to monitor:<br />
the accuracy of news reports,<br />
tobacco industry marketing,<br />
smokeless tobacco users’ understanding of the new regulations,<br />
what smokeless tobacco users interpret the new regulations to mean relative<br />
to the hazard of the products remaining on the market and<br />
35
whether understanding about the hazard of the remaining products is<br />
influencing initiation or cessation rates.<br />
Regulators should pursue whatever corrective action is necessary to prevent<br />
consumers from being misled. These monitoring and surveillance concerns<br />
are described in more detail in the WHO report, Evaluation of new or modified<br />
tobacco products (18).<br />
3.9 Recommendations<br />
All products that deliver nicotine for human consumption should be<br />
regulated.<br />
Smokeless tobacco products should be regulated by controlling the contents<br />
of the products.<br />
The metric for measuring toxicants in smokeless tobacco should be the<br />
amount per gram of dry weight of tobacco.<br />
Initially, upper limits should be set for two nitrosamines N-nitrosonornicotine<br />
(NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone<br />
(NNK), and one polycyclic aromatic hydrocarbon, benzo[a]pyrene.<br />
The combined concentration of NNN plus NNK in smokeless tobacco<br />
should be limited to 2 μg/g dry weight of tobacco.<br />
The concentration of benzo[a]pyrene in smokeless tobacco should be<br />
limited to 5 ng/g dry weight of tobacco.<br />
Regulation of the distribution and sale of smokeless tobacco products<br />
should include a requirement for affixation of the date by which the<br />
product must be sold or returned to the manufacturer and a requirement<br />
for refrigeration of the product before sale in order to limit the increase<br />
in the concentration of nitrosamines that occurs over time of storage.<br />
3.10 Acknowledgement<br />
36<br />
This report was prepared on the basis of a discussion paper written for TobReg<br />
by Stephen S. Hecht, Ph.D., American Cancer Society Research Professor<br />
and Wallin Land Grant Professor of Cancer Prevention at the University of<br />
Minnesota Masonic Cancer Center, Minneapolis, Minnesota.
3.11 References<br />
1. The scientific basis of tobacco product regulation: report of a WHO study<br />
group. Geneva, World Health Organization, 2007 (WHO Technical Report<br />
Series, No. 945).<br />
2. The scientific basis of tobacco product regulation: second report of a WHO<br />
study group. Geneva, World Health Organization, 2008 (WHO Technical Report<br />
Series, No. 951).<br />
3. International Agency for Research on Cancer. Smokeless tobacco and some<br />
tobacco-specific N-nitrosamines, 2007. Lyon, IARC Press (IARC Monographs<br />
on the Evaluation of Carcinogenic Risks to Humans, Volume 89).<br />
4. Teo KK et al. Tobacco use and risk of myocardial infarction in 52 countries in<br />
the INTERHEART study: a case–control study. Lancet, 2006, 368:647–658.<br />
5. Brunnemann KD, Hoffmann D. Chemical composition of smokeless tobacco<br />
products. In: Smokeless tobacco or health. An international perspective.<br />
Bethesda, Maryland, National Cancer Institute, 1992 (Smoking and Tobacco<br />
Control Monograph No. 2).<br />
6. International Agency for Research on Cancer. Tobacco smoke and involuntary<br />
smoking. Lyon, IARC Press, 2004 (IARC Monographs on the Evaluation of<br />
Carcinogenic Risks to Humans, Volume 83).<br />
7. Gothiatek standards. 4-12-2008. Stockholm, Swedish Match Company.<br />
http://www.swedishmatch.com/en/Snus-and-health/Our-quality-standard-<br />
GothiaTek/GothiaTek-standards/ Access 4-12-2008<br />
8. Zaridze DG et al. Carcinogenic substances in Soviet tobacco products. In:<br />
O’Neill IK, Chen J, Bartsch H eds. Relevance to human cancer of N-nitroso<br />
compounds, tobacco smoke and mycotoxins, Lyon, IARC Press, 1991 (IARC<br />
Scientific Publications No. 105:485–488).<br />
9. O’Connor RJ, Hurley PJ. Existing technologies to reduce specific toxicant<br />
emissions in cigarette smoke. Tobacco Control, 2008, Suppl 1:i39–48.<br />
10. International Agency for Research on Cancer. Polynuclear aromatic<br />
compounds. Part 1, chemical, environmental, and experimental data, 1983.<br />
Lyon, IARC Press (IARC Monographs on the Evaluation of Carcinogenic Risks<br />
to Humans, Volume 32).<br />
11. McNeill A et al. Levels of toxins in oral tobacco products in the UK. Tobacco<br />
Control, 2006, 15:64–67.<br />
12. Stepanov I et al. New and traditional smokeless tobacco: comparison of toxicant<br />
and carcinogen levels. Nicotine and Tobacco Research, 2008, 10:1773–1782.<br />
13. Idris AM et al. Unusually high levels of carcinogenic tobacco-specific<br />
nitrosamines in Sudan snuff (toombak). Carcinogenesis, 1991, 12:1115–1118.<br />
14. Idris AM, Ahmed HM, Malik MO. Toombak dipping and cancer of the oral cavity<br />
in the Sudan: a case–control study. International Journal of Cancer, 1995,<br />
63:477–480.<br />
15. Idris AM, Prokopczyk B, Hoffmann D. Toombak: a major risk factor for cancer<br />
of the oral cavity in Sudan. Preventive Medicine, 1994, 23:832–839.<br />
16. Straif K et al. Carcinogenicity of polycyclic aromatic hydrocarbons. Lancet<br />
Oncology, 2005, 6:931–932.<br />
37
38<br />
17. Richter P et al. Surveillance of moist snuff: total nicotine, moisture, pH, unionized<br />
nicotine, and tobacco-specific nitrosamines. Nicotine and Tobacco<br />
Research, 2008, 10:1645–1652.<br />
18. WHO Scientific Advisory Committee on Tobacco Product Regulation.<br />
Statement of principles guiding the evaluation of new or modified tobacco<br />
products. Geneva, World Health Organization, 2003.
4. Overall recommendations<br />
This report addresses two types of products that currently concern scientists<br />
because of their potential for harming public health and the inadequacy of<br />
regulations governing their promotion, sale and use. Electronic nicotine delivery<br />
systems (ENDS) deliver nicotine and other substances directly to the<br />
lung, unaccompanied by tobacco smoke. They are marketed under a variety<br />
of brand names and descriptions around the world but fall into a regulatory<br />
gap in most countries. Few studies have documented their content or emissions,<br />
and claims that WHO approves their use for smoking cessation have<br />
been circulated. Smokeless tobacco products are also used in many countries,<br />
and scientifically documented differences have been found in their content<br />
and formulations that may explain the observed differences in adverse health<br />
outcomes. Substantial variation in carcinogen levels has been found in<br />
smokeless tobacco products marketed in different regions and among products<br />
marketed within a region. It is desirable and feasible to lower these levels<br />
through better manufacturing and sales practices.<br />
Of the topics discussed at the fifth meeting of TobReg, ENDS and smokeless<br />
tobacco were deemed to be most important for issuing recommendations for<br />
regulation.<br />
4.1 Electronic nicotine delivery systems (ENDS): regulatory<br />
recommendations and research needs<br />
4.1.1 Main recommendations<br />
ENDS designed for direct nicotine delivery to the respiratory system fall into<br />
a regulatory gap in most countries, escaping regulation as drugs and avoiding<br />
the controls on tobacco products. There is currently insufficient evidence to<br />
assess whether ENDS products could be used to aid cessation, create or sustain<br />
addiction, or deliver constituents other than nicotine to smokers. Clinical<br />
trials, behavioural and psychological studies and post-marketing studies at<br />
individual and population levels are needed to answer these questions. Claims<br />
imputing health benefits, reduced harm or use in smoking cessation should<br />
be prohibited until they are scientifically proven. ENDS products should be<br />
39
egulated as nicotine delivery devices; when such regulation is not possible,<br />
they should be subjected under tobacco control laws to regulation of contents<br />
and labelling, prohibitions against public use and restrictions on advertising,<br />
promotion and sponsorship.<br />
4.1.2 Significance for public health policies<br />
ENDS might benefit public health if they promote smoking cessation, but<br />
they might create public health risks if they sustain nicotine dependence by<br />
allowing nicotine intake where smoking is prohibited or if they increase initiation<br />
and transition to cigarette smoking among people who would not<br />
otherwise have used tobacco. Smokers who attempt to quit may use ENDS<br />
in place of evidence-based treatments, potentially delaying smoking cessation<br />
and increasing the risks for smoking-attributable disease if they are<br />
ultimately ineffective as nicotine replacement therapy devices.<br />
4.1.3 Implications for WHO programmes<br />
WHO continues to support pharmacotherapy only when scientific studies<br />
have demonstrated predictable outcomes under specified conditions and<br />
when products have been approved as safe and effective by major drug regulatory<br />
authorities. WHO strongly encourages its Member States to prohibit<br />
manufacturers of ENDS from issuing claims that WHO endorses their products<br />
as legitimate tobacco cessation aids. Member States should ensure that<br />
the manufacturers of these products comply with all existing regulatory requirements<br />
to preclude unsubstantiated claims that may derail public health<br />
efforts in tobacco control.<br />
4.2 Smokeless tobacco: setting regulatory limits for carcinogenic<br />
components<br />
4.2.1 Main recommendations<br />
40<br />
The regulatory strategy previously advocated by TobReg for cigarettes<br />
should be extended to mandating reductions in toxicant levels in smokeless<br />
tobacco. Two groups of toxicants should take priority for regulatory limits<br />
because of their carcinogenic potency and the possibility of achieving substantially<br />
lower concentrations in smokeless tobacco with existing techniques:<br />
tobacco-specific N-nitrosamines (TSNA) and polycyclic aromatic<br />
hydrocarbons (PAH). Upper limits should be set for the combined concentrations<br />
of N-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1butanone<br />
at 2 μg/g dry weight of tobacco and for benzo[a]pyrene as a marker<br />
for carcinogenic PAH at 5 ng/g dry weight of tobacco. Regulators should<br />
inform consumers that, like cigarettes, smokeless tobacco products that meet
safety standards may be no less hazardous, and they should prohibit product<br />
ranking or publicizing test results that are likely to influence user behaviour<br />
in ways that will cause harm. Measuring, testing and reporting should be<br />
verified by independent laboratories or government agencies, and expiration<br />
dates and refrigeration requirements should be enforced to limit the accumulation<br />
of TSNA.<br />
4.2.2 Significance for public health policies<br />
Differences in the disease risks associated with smokeless tobacco use in<br />
different parts of the world reflect differences in the toxicity of the products<br />
available on various markets. While existing evidence has not established that<br />
lowering TSNA or PAH levels in smokeless tobacco products will lower<br />
cancer risks, it is difficult to justify allowing high levels of known carcinogenic<br />
constituents in a product that is known to cause cancer, when lower<br />
levels are readily achievable with existing technology. As they do for other<br />
consumer products, regulators should lower the concentrations of carcinogens<br />
present in smokeless tobacco by limiting the concentrations that can be<br />
present in products that are marketed. As lower detection limits become technically<br />
feasible, more aggressive targets for mandated lowering can be set by<br />
regulatory authorities.<br />
4.2.3 Implications for WHO programmes<br />
WHO should begin by advising the regulation of manufactured smokeless<br />
tobacco products, even though individuals and cottage industries, which are<br />
not easily regulated, often dominate the use and production of smokeless<br />
tobacco. WHO should recommend that companion programmes be set up to<br />
educate cottage industry producers and to improve production approaches for<br />
small producers, in order to address the more difficult problem of limiting<br />
carcinogen concentrations in non-manufactured smokeless tobacco. Finally,<br />
WHO should reject the notion that manufactured products with higher toxicant<br />
levels are acceptable in countries with few economic resources.<br />
41
This report presents the conclusions reached and recommendations made by the members of the WHO Study Group on<br />
Tobacco Product Regulation at its fifth meeting, during which it reviewed two background papers specially commissioned<br />
for the meeting and which dealt, respectively, with the following two themes.<br />
1. Devices designed for the purpose of nicotine delivery to the respiratory system in which tobacco is not necessary for<br />
their operation.<br />
2. Setting regulatory limits for carcinogens in smokeless tobacco.<br />
The Study Group's recommendations in relation to each theme are set out at the end of the section dealing with that<br />
theme; its overall recommendations are summarized in section 4.<br />
ISBN 978 92 4 120955 7
Nachschlagewerk zum Thema E-Zigaretten<br />
36 WHO Study Group on Tobacco Product Regula-<br />
tion. (Abstrakt)
http://www.who.int/tobacco/global_interaction/tobreg/publications/tsr_955/en/index.html 1/1<br />
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Publication details<br />
Publication date: 2010<br />
Languages: English<br />
ISBN: 978 92 4 120955 7<br />
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The WHO Tobacco Free Initiative announces the third volume of the WHO Study Group on Tobacco<br />
Product Regulation (TobReg) Technical Report Series on the Scientific Basis of Tobacco Product<br />
Regulation. This WHO Technical Report Series makes available the findings of an international group<br />
of experts that provide WHO with the latest scientific and technical advice in the area of product<br />
regulation.<br />
The third report presents the conclusions reached and recommendations made by the members of<br />
the WHO Study Group on Tobacco Product Regulation at its fifth meeting, during which it reviewed<br />
two background papers specially commissioned for the meeting and which dealt, respectively, with<br />
the following two themes.<br />
1. Devices designed for the purpose of nicotine delivery to the respiratory system in which tobacco is<br />
not necessary for their operation.<br />
2. Setting regulatory limits for carcinogens in smokeless tobacco.<br />
The Study Group's recommendations in relation to each theme are set out at the end of the section<br />
dealing with that theme. Its overall recommendations are summarized in section 4.<br />
The Study Group intends this new set of recommendations to be useful to WHO Member States and<br />
national policymakers and regulators in shaping tobacco control policy. The English will be available<br />
shortly in print format, and the other UN-language versions will be available soon.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
37 The effects of nicotine, denicotinized tobacco,<br />
and nicotine-containing tobacco on cigarette<br />
craving, withdrawal, and self-administration in<br />
male and female smokers.
http://www.ncbi.nlm.nih.gov/pubmed/20168213 1/2<br />
US National Library of Medicine<br />
National Institutes of Health<br />
Resources How To<br />
Behav Pharmacol. 2010 Mar;21(2):144-52. doi: 10.1097/FBP.0b013e328337be68.<br />
The effects of nicotine, denicotinized tobacco, and nicotine-containing<br />
tobacco on cigarette craving, withdrawal, and self-administration in male<br />
and female smokers.<br />
Barrett SP.<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Department of Psychology, Dalhousie University, Halifax NS B3H 4J1,, Canada. Sean.Barrett@Dal.ca<br />
Abstract<br />
The effects of the acute administration of nicotine [through nicotine inhalers (NI) and placebo<br />
inhalers (PI)], nicotine-containing tobacco (NT), and denicotinized tobacco (DT), on smokers'<br />
subjective responses and motivation to smoke were examined in 22 smokers (12 male, 10 female;<br />
11 low dependent, 11 high dependent). During four randomized blinded sessions, participants selfadministered<br />
NI, PI, NT, or DT, and assessed their effects using Visual Analogue Scales and the<br />
Brief Questionnaire of Smoking Urges. They could then self-administer their preferred brand of<br />
cigarettes using a progressive ratio task. NT and DT were each associated with increased<br />
satisfaction and relaxation as well as decreased craving relative to the inhalers and NT increased<br />
ratings of stimulation relative to each of the other products. Both NT and DT delayed the onset of<br />
preferred tobacco self-administration relative to NI and PI but only NT reduced the total amount selfadministered.<br />
Sex differences were evident in the effects of DT on withdrawal-related cravings with<br />
women experiencing greater DT-induced craving relief than men. Findings suggest that DT is<br />
effective in acutely reducing many smoking abstinence symptoms, especially in women, but a<br />
combination of nicotine and non-nicotine tobacco ingredients may be necessary to suppress<br />
smoking behavior.<br />
PMID: 20168213 [PubMed - indexed for MEDLINE]<br />
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The acute effects of nicotine on<br />
the subjective [Behav and Pharmacol. behavioural 2012]<br />
Effect of nicotine lozenges on<br />
affective smoking [Clin withdrawal Ther. 2008]<br />
Smokers deprived of cigarettes<br />
[Psychopharmacology for 72 h: effect of nicotine (Berl). 2002]<br />
Review [Smoking reduction and<br />
temporary abstinence: [J Mal Vasc. new 2003]<br />
Review Nicotine selfadministration.<br />
[Nicotine Tob Res. 1999]<br />
Cited by 4 PubMed<br />
Central articles<br />
See reviews...<br />
See all...<br />
Oral Nicotine Self-Administration<br />
in Rodents. [J Addict Res Ther. 2012]<br />
Acute phenylalanine/tyrosine<br />
[Neuropsychopharmacology. depletion reduces motivation 2011] to<br />
Effects of 24 hours of tobacco<br />
withdrawal [Nicotine and subsequent Tob Res. 2011]<br />
Related information<br />
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Substance (MeSH Keyword)<br />
Cited in PMC<br />
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denicotinized tobacco, PubMed and<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
38 Tracking the rise in popularity of electronic nico-<br />
tine delivery systems electronic cigarettes using<br />
search query surveillance.
http://www.ncbi.nlm.nih.gov/pubmed/21406279 1/2<br />
US National Library of Medicine<br />
National Institutes of Health<br />
Resources How To<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Am J Prev Med. 2011 Apr;40(4):448-53. doi: 10.1016/j.amepre.2010.12.007.<br />
Tracking the rise in popularity of electronic nicotine delivery systems<br />
(electronic cigarettes) using search query surveillance.<br />
Ayers JW, Ribisl KM, Brownstein JS.<br />
Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA. jayers@jhsph.edu<br />
Abstract<br />
BACKGROUND: Public interest in electronic nicotine delivery systems (ENDS) is undocumented.<br />
Related citations in<br />
PubMed<br />
PURPOSE: By monitoring search queries, ENDS popularity and correlates of their popularity were<br />
assessed in Australia, Canada, the United Kingdom (UK), and the U.S.<br />
Tobacco-free electronic<br />
cigarettes and [Tob cigars Control. deliver2007]<br />
METHODS: English-language Google searches conducted from January 2008 through September<br />
2010 were compared to snus, nicotine replacement therapy (NRT), and Chantix® or Champix®.<br />
Searches for each week were scaled to the highest weekly search proportion (100), with lower<br />
values indicating the relative search proportion compared to the highest-proportion week (e.g.,<br />
Electronic cigarettes as a<br />
smoking-cessation: [Am J Prev tool Med. results 2011]<br />
World: E-cigarettes are here.<br />
[Tob Control. 2009]<br />
50=50% of the highest observed proportion). Analyses were performed in 2010.<br />
Review Nicotine transdermal<br />
[Methods systems: Find Exp pharmaceutical Clin Pharmacol. and 2000]<br />
RESULTS: From July 2008 through February 2010, ENDS searches increased in all nations studied<br />
except Australia, there an increase occurred more recently. By September 2010, ENDS searches<br />
were several-hundred-fold greater than searches for smoking alternatives in the UK and U.S., and<br />
Review A review of the efficacy<br />
of smoking-cessation [Clin Ther. 2008]<br />
were rivaling alternatives in Australia and Canada. Across nations, ENDS searches were highest in<br />
See reviews...<br />
the U.S., followed by similar search intensity in Canada and the UK, with Australia having the<br />
fewest ENDS searches. Stronger tobacco control, created by clean indoor air laws, cigarette taxes,<br />
and anti-smoking populations, were associated with consistently higher levels of ENDS searches.<br />
See all...<br />
CONCLUSIONS: The online popularity of ENDS has surpassed that of snus and NRTs, which have<br />
been on the market for far longer, and is quickly outpacing Chantix or Champix. In part, the<br />
association between ENDS's popularity and stronger tobacco control suggests ENDS are used to<br />
bypass, or quit in response to, smoking restrictions. Search query surveillance is a valuable, realtime,<br />
free, and public method to evaluate the diffusion of new health products. This method may be<br />
generalized to other behavioral, biological, informational, or psychological outcomes manifested on<br />
search engines.<br />
Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights<br />
reserved.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
39 Electronic cigarettes as a harm reduction strate-<br />
gy for tobacco control a step forward or a repeat<br />
of past mistakes.
http://www.ncbi.nlm.nih.gov/pubmed/21150942 1/2<br />
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J Public Health Policy. 2011 Feb;32(1):16-31. doi: 10.1057/jphp.2010.41. Epub 2010 Dec 9.<br />
Electronic cigarettes as a harm reduction strategy for tobacco control: a<br />
step forward or a repeat of past mistakes?<br />
Cahn Z, Siegel M.<br />
PubMed<br />
Display Settings: Abstract Send to:<br />
Department of Political Science, University of California at Berkeley, UC Berkeley Department of Political Science, 210<br />
Barrow s Hall #1950, Berkeley, CA 94720-1950, USA.<br />
Abstract<br />
The issue of harm reduction has long been controversial in the public health practice of tobacco<br />
control. Health advocates have been reluctant to endorse a harm reduction approach out of fear that<br />
tobacco companies cannot be trusted to produce and market products that will reduce the risks<br />
associated with tobacco use. Recently, companies independent of the tobacco industry introduced<br />
electronic cigarettes, devices that deliver vaporized nicotine without combusting tobacco. We review<br />
the existing evidence on the safety and efficacy of electronic cigarettes. We then revisit the tobacco<br />
harm reduction debate, with a focus on these novel products. We conclude that electronic<br />
cigarettes show tremendous promise in the fight against tobacco-related morbidity and mortality. By<br />
dramatically expanding the potential for harm reduction strategies to achieve substantial health<br />
gains, they may fundamentally alter the tobacco harm reduction debate.<br />
PMID: 21150942 [PubMed - indexed for MEDLINE]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
40 Chronic Idiopathic Neutrophilia in A Smoker, Re-<br />
lieved after Smoking Cessation with the Use of<br />
Electronic Cigarette.
Clinical Medicine Insights: Case Reports<br />
CASe RepoRT<br />
doi: 10.4137/CCRep.S11175<br />
This article is available from http://www.la-press.com.<br />
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chronic Idiopathic neutrophilia in A smoker, Relieved after<br />
smoking cessation with the Use of electronic cigarette:<br />
a case Report<br />
Konstantinos e. Farsalinos 1 and Giorgio Romagna 2<br />
1 onassis Cardiac Surgery Center, Kallithea, Greece. 2 Abich s.r.l. Toxicological Laboratory, Verbania, Italy.<br />
Corresponding author email: kfarsalinos@gmail.com<br />
Abstract<br />
Introduction: Smoking is a major risk factor for a variety of diseases. Electronic cigarettes are battery-operated devices that deliver<br />
nicotine to the lungs by evaporation of a liquid. Chronic idiopathic neutrophilia is a condition characterized by elevated white blood cell<br />
and neutrophil counts without any underlying disease; smoking has been implicated as a potential cause.<br />
Case Presentation: A male Caucasian patient, born in 1977, presented in September 2005 with asymptomatic elevation of white blood<br />
cell and neutrophil count, and mildly-elevated C-reactive protein levels. He was a smoker since 1996 and was treated with 20 mg/day<br />
of simvastatin since 2003 due to hyperlipidemia. Clinical examination, and laboratory and imaging investigations ruled out any infectious,<br />
haematological, rheumatological, or endocrine conditions. He was followed-up regularly and was advised to stop smoking. He<br />
had 2 unsuccessful attempts to quit smoking; one was unassisted and the second was performed with the use of both varenicline and<br />
nicotine replacement therapy (patches). During the subsequent 6.5 years, his leukocyte and C-reactive protein levels were repeatedly<br />
elevated; the condition was consistent with chronic idiopathic neutrophilia. In February 2012, he started using electronic cigarettes and<br />
he managed to quit smoking within 10 days. After 6 months, laboratory examination showed normalized leukocyte count and C-reactive<br />
protein levels, confirmed immediately by a second laboratory and by repeated tests after 1 and 2 months.<br />
Conclusion: Smoking cessation with the use of electronic cigarette led to reversal of chronic idiopathic neutrophilia. The daily use of<br />
electronic cigarette may help preserve the beneficial effects of smoking cessation.<br />
Keywords: electronic cigarette, smoking, chronic idiopathic neutrophilia, inflammation, smoking cessation<br />
Clinical Medicine Insights: Case Reports 2013:6 15–21<br />
This is an open access article. Unrestricted non-commercial use is permitted provided the original work is properly cited.<br />
Clinical Medicine Insights: Case Reports 2013:6 15
Farsalinos and Romagna<br />
Introduction<br />
Cigarette smoking is a major cause of disease, affecting<br />
several systems in the human body. 1,2 Although<br />
reducing cigarette consumption does not improve<br />
prognosis, 3 smoking cessation has important beneficial<br />
socioeconomic and health-related implications. 4,5<br />
However, quitting smoking is a very difficult task.<br />
Smokers that try to quit without any medical aid or<br />
treatment have extremely low success rate. 6 Although<br />
several pharmaceutical products are available for<br />
smoking cessation, long term quit-rates are relatively<br />
low. 7 Therefore, tobacco harm reduction strategies<br />
and products have been developed, with the main goal<br />
to reduce the amount of harmful substances administered<br />
to the human body. 8<br />
Electronic cigarettes have been introduced to the<br />
market in recent years as an alternative to smoking.<br />
They are hand-held electronic nicotine-delivery<br />
devices consisting of a battery, a cartridge containing<br />
liquid, and an electrical resistance that is heated<br />
through the battery power and evaporates the liquid.<br />
The do not contain tobacco and there is no combustion<br />
involved. They deal with the chemical addiction<br />
by delivering nicotine to the lungs and consequently<br />
to the circulation. Although millions of people use<br />
them all over the world, there is lack of clinical evidence<br />
on their efficacy in reversing smoking-related<br />
disease and conditions.<br />
Chronic idiopathic neutrophilia (CIN) is a condition<br />
characterized by asymptomatic elevation of white<br />
blood cells (WBCs) and neutrophil count that persists<br />
for years without any underlying disease. 9 Smoking<br />
has been implicated as a cause of this condition, 9,10<br />
and leukocyte count is a predictor of future cardiovascular<br />
events. 11,12<br />
To the best of our knowledge, we report for the first<br />
time a case study of a subject with CIN that was reversed<br />
by smoking cessation with the daily use of electronic<br />
cigarettes. Written informed consent was obtained from<br />
the patient for presenting this case report.<br />
case presentation<br />
A male Caucasian, born in 1977, was presented in<br />
September 2005 with an elevated WBC count found<br />
during a routine check-up. At this time, he had been<br />
a smoker since 1996 (9 pack-years at the time of<br />
presentation). He had a positive family history of premature<br />
coronary heart disease and hyperlipidemia,<br />
which was treated with simvastatin at 20 mg/day since<br />
2003. Complete blood count tests performed 9 and<br />
18 months earlier were normal (WBC: 8900–9700/<br />
µL, neutrophils: 4183–4462/µL, lymphocytes: 4005–<br />
4268/µL, eosinophils: 89–194/µL, basophils: 623–<br />
776/µL). At presentation, his WBC count was 14,600/<br />
µL (8614/µL neutrophils, 5256/µL lymphocytes, 292/<br />
µL eosinophils and 438/µL basophils). Hematocrit<br />
(45.2%) and platelet count (305,000/µL) were within<br />
normal range. Blood smear was normal. The test was<br />
repeated twice in a different laboratory with similar<br />
results. He was completely asymptomatic, had no history<br />
of recent infections or trauma and reported no<br />
fever. He had no changes in body weight or appetite<br />
over the past months; his body mass index (BMI) was<br />
27.7 kg/m 2 at presentation. Clinical examination was<br />
normal and he was afebrile. Routine laboratory examinations<br />
did not reveal any renal or liver dysfunction.<br />
Thyroid hormones were within normal range,<br />
as were serum cortisol levels. He did not report any<br />
recent intake of steroid drugs. C-reactive protein was<br />
elevated at 14 mg/L (normal range , 5 mg/L). Rheumatologic<br />
and infectious disease work-up (including<br />
ANA, anti-dsDNA, Le-test, Ra-test, ASTO, CMV and<br />
EBV antibodies, Wright test and Widal reaction) were<br />
all negative for disease. Chest x-ray, echocardiogram<br />
and upper abdominal ultrasound were normal. Spleen<br />
and liver size were within normal limits. A CT-scan of<br />
thorax and abdomen were also normal.<br />
He was invited for a repeat complete blood count after<br />
2 months, with WBC reaching 21,000/µL (neutrophils:<br />
14,280/µL, lymphocytes: 5250/µL, eosinophils:<br />
630/µL, basophils: 840/µL). Once again he was<br />
asymptomatic and with no signs of infection or any<br />
other inflammatory condition. He was instructed<br />
to stop intake of simvastatin and repeat the examination<br />
in another 2 months. In January 2006, leukocytosis<br />
was still present (WBC: 17,900/µL,<br />
neutrophils: 11635/µL, lymphocytes: 5012/µL,<br />
eosinophils: 537/µL, basophils: 716/µL). He was prescribed<br />
atorvastatin at 20 mg/day because of elevated<br />
LDL levels. The diagnosis of CIN was suspected and<br />
he was offered a bone marrow aspiration biopsy to<br />
rule out other conditions. He refused the exam and<br />
was scheduled for routine follow-up. He was also<br />
advised to stop smoking.<br />
Figure 1 displays all WBC counts over the course of<br />
7 years since presentation. All results were consistent<br />
16 Clinical Medicine Insights: Case Reports 2013:6
25000<br />
20000<br />
15000<br />
10000<br />
5000<br />
0<br />
Jan<br />
2004<br />
Jul<br />
2004<br />
Jan<br />
2005<br />
Time<br />
of<br />
presentation<br />
Jul<br />
2005<br />
Jan<br />
2006<br />
1st attempt<br />
to quit<br />
smoking<br />
Jul<br />
2006<br />
Jan<br />
2007<br />
Smoking cessation by e-cigarette relieves chronic idiopathic neutrophilia<br />
Jul<br />
2007<br />
Jan<br />
2008<br />
Jul<br />
2008<br />
Jan<br />
2009<br />
Jul<br />
2009<br />
2nd attempt<br />
to quit<br />
smoking<br />
Jan<br />
2010<br />
Jul<br />
2010<br />
Jan<br />
2011<br />
WBC<br />
Neutrophils<br />
Lymphocytes<br />
Quit smoking<br />
with electronic<br />
cigarette<br />
Figure 1. White blood cell, neutrophil and lymphocyte count over the course of 7 years follow-up of the patient.<br />
notes: Time of presentation and two unsuccessful attempts of smoking cessation are indicated with arrows. The time of initiation of electronic cigarette,<br />
leading to smoking cessation, is also indicated by an arrow. Normal value for neutrophils is less than 8,000/µL (horizontal red line).<br />
with CIN, and mild elevations in C-reactive protein<br />
were also noted (Fig. 2). He did not receive any other<br />
medications during this period besides antipyretics<br />
for 2 episodes of common cold; all laboratory<br />
examinations were performed at least 10 weeks far<br />
from the common cold episodes. He had two unsuccessful<br />
attempts to quit smoking, one without any<br />
medical treatment in 2006 and one with varenicline<br />
plus nicotine patches in 2010. A change in statin<br />
Jul<br />
2011<br />
Jan<br />
2012<br />
Jul<br />
2012<br />
prescription from atorvastatin (20 mg/day) to rosuvastatin<br />
(20 mg/day) was done in May 2010, but no<br />
difference was observed in WBC count in subsequent<br />
measurements.<br />
In February 2012 he managed to quit smoking by<br />
the use of electronic cigarettes. It should be mentioned<br />
that use of electronic cigarettes was a personal choice<br />
of the patient; no advice or recommendation to use it<br />
was provided by the physicians, since it has not been<br />
Clinical Medicine Insights: Case Reports 2013:6 17
Farsalinos and Romagna<br />
20<br />
15<br />
10<br />
5<br />
0<br />
Jan<br />
2004<br />
Jul<br />
2004<br />
Jan<br />
2005<br />
Time<br />
of<br />
presentation<br />
Jul<br />
2005<br />
Jan<br />
2006<br />
1st attempt<br />
to quit<br />
smoking<br />
Jul<br />
2006<br />
Jan<br />
2007<br />
Jul<br />
2007<br />
approved as a smoking cessation method. He reported<br />
complete smoking cessation after 10 days of using the<br />
device. One month earlier, his complete blood count<br />
was consistent with CIN. In August 2012, routine<br />
follow-up showed no leukocytosis (WBC: 8800/µL,<br />
neutrophils: 4400/µL, lymphocytes: 3344/µL, eosinophils:<br />
352/µL, basophils: 704/µL). C-reactive protein<br />
levels were also normalized. His BMI was 28.4 kg/m 2 .<br />
The test was repeated in 2 different laboratories, with<br />
similar results. Further tests, 1, 2 and 3 months later<br />
revealed no leukocytosis. During this period, he was<br />
using the electronic cigarette daily, consuming liquid<br />
with nicotine concentration of 9 mg/mL. Smoking<br />
abstinence was confirmed during his last three visits<br />
by measuring carbon monoxide in exhaled breath; it<br />
was within normal limits (4 ppm).<br />
Discussion<br />
To the best of our knowledge, this is the first study<br />
which reports that smoking cessation with the use of<br />
Jan<br />
2008<br />
Jul<br />
2008<br />
Jan<br />
2009<br />
2nd attempt<br />
to quit<br />
smoking<br />
Jul<br />
2009<br />
Jan<br />
2010<br />
C-reactive protein<br />
Jul<br />
2010<br />
Quit smoking<br />
with electronic<br />
cigarette<br />
Figure 2. C-reactive protein levels over the course of 7 years follow-up of the patient.<br />
notes: Time of presentation and two unsuccessful attempts of smoking cessation are indicated with arrows. The time of initiation of electronic cigarette,<br />
leading to smoking cessation, is also indicated by an arrow. Normal reference value for C-reactive protein is less than 5 mg/L (horizontal red line).<br />
Jan<br />
2011<br />
Jul<br />
2011<br />
Jan<br />
2012<br />
Jul<br />
2012<br />
electronic cigarette leads to reversal of chronic idiopathic<br />
neutrophilia. The most important message is<br />
that despite the daily use of electronic cigarette by<br />
this patient, the beneficial effects of smoking cessation<br />
were maintained.<br />
Electronic cigarettes were invented in 2003, with<br />
awareness and use increasing significantly over the<br />
past 3 years. 13 They have been introduced to the<br />
market as tobacco harm-reduction products and<br />
they may have a unique role in this field. They work<br />
by evaporating a nicotine-containing liquid, which<br />
is subsequently inhaled by the user. In addition to<br />
nicotine, the constituents of liquids used for evaporation<br />
are limited to propylene glycol, glycerol, and<br />
flavorings. Since they deliver nicotine and at the<br />
same time resemble the act of smoking by production<br />
of visible vapor, they deal with both the chemical<br />
(nicotine delivery) and behavioral components<br />
of cigarette addiction. 14 A non-randomized study by<br />
Polosa et al 15 and an internet survey by Siegel et al 16<br />
18 Clinical Medicine Insights: Case Reports 2013:6
suggested that they may be effective as a smoking<br />
cessation tool.<br />
The absence of tobacco and the lack of combustion<br />
are important features in the health-related profile of<br />
these products. Until recently, research on the composition,<br />
toxicology, and clinical effects of electronic<br />
cigarettes was scarce. Thus, FDA and WHO publicly<br />
expressed serious concerns about electronic cigarette<br />
use in 2009, recommending that their use should<br />
be avoided. Cahn and Siegel 14 summarized several<br />
chemical analyses performed until 2011, showing that<br />
electronic cigarette liquid contents are far less harmful<br />
compared to tobacco. 14 For nitrosamines they mentioned<br />
that, when present, the amount was 500-fold to<br />
1400-fold reduced in electronic compared to tobacco<br />
cigarettes. 14 Substances produced from combustion<br />
of tobacco cigarettes, like polycyclic aromatic hydrocarbons,<br />
were not present in any of the liquids tested.<br />
Although still inadequate, research on electronic<br />
cigarettes has progressed over the past year. During<br />
the 14th annual meeting of the Society for Research<br />
on Nicotine and Tobacco Europe, Romagna et al 17<br />
presented a cytotoxic study comparing electronic<br />
cigarette vapor with tobacco cigarette smoke; they<br />
found that vapor extract from 10 different commercially<br />
available liquids were not cytotoxic to cultured<br />
mammalian cells compared to significant cytotoxicity<br />
observed from tobacco smoke extract. 17 Only three<br />
clinical studies on the effects of electronic cigarettes<br />
on human health have been performed. Vardavas<br />
et al 18 found that 5 minute use of electronic cigarette<br />
produced a mild but significant elevation in pulmonary<br />
resistance. 18 However, no comparison with the<br />
effects of tobacco cigarettes was performed. Flouris<br />
et al 19 found that no elevation in WBC count was<br />
found after electronic cigarette use; in comparison,<br />
WBC and neutrophil counts were significantly elevated<br />
immediately after tobacco cigarette smoking. 19<br />
Farsalinos et al 20 studied smokers and electronic cigarette<br />
users with echocardiography before and after<br />
smoking and electronic cigarette use respectively. 20<br />
Acute diastolic dysfunction was observed in smokers<br />
immediately after smoking 1 cigarette, while diastolic<br />
function was preserved after using the electronic cigarette<br />
for 7 minutes. Interestingly, although electronic<br />
cigarette users were previously heavy smokers, it took<br />
them on average only 2 days to quit smoking with the<br />
use of the device.<br />
Smoking cessation by e-cigarette relieves chronic idiopathic neutrophilia<br />
Despite all this data and the fact that no study<br />
has found that electronic cigarettes are more harmful<br />
when compared to tobacco cigarettes, it must<br />
be emphasized that research is still in its infancy.<br />
More studies are needed, especially clinical studies,<br />
on their long-term effects. It will take several years,<br />
however, before such studies are published as awareness<br />
and use of electronic cigarettes has increased<br />
only recently. Delay will also occur as the knowledge<br />
that smoking-related disease and the beneficial<br />
effects of smoking cessation take several years before<br />
becoming clinically evident. Until that time, research<br />
should focus on the pathophysiological mechanisms<br />
by which smoking causes disease and should proceed<br />
on both laboratory and clinical level. The crucial scientific<br />
question that should be addressed is whether<br />
electronic cigarettes are less harmful compared to<br />
tobacco cigarettes, since they should be marketed<br />
solely as a tobacco harm reduction product and not<br />
as a new habit for the general population. In any case,<br />
regulation and specific quality standards should be<br />
implemented as the use of non-pharmaceutical grade<br />
nicotine or other constituents may lead to the presence<br />
of toxic tobacco impurities in the liquids, which<br />
will be subsequently inhaled by the user. 14<br />
Although we cannot exclude that some constituents<br />
of electronic cigarette vapor may have had beneficial<br />
effects in reducing WBC count in our patient,<br />
the most probable explanation is that reversal of CIN<br />
was caused by smoking cessation itself. Smoking<br />
causes diseases by a variety of mechanisms, including<br />
inflammation. 21 It causes a 20%–25% increase in<br />
peripheral blood leukocyte count 22 in addition to elevated<br />
levels of inflammatory markers like C-reactive<br />
protein. 23 CIN is an uncommon condition associated<br />
with greater elevation in WBCs and neutrophils than<br />
those observed in the majority of smokers. Smoking<br />
however has been implicated as a cause for the<br />
condition. The patient had persistently elevated WBC<br />
count and mildly elevated C-reactive protein levels,<br />
without any underlying disease. This may represent a<br />
state of low-grade inflammation, which is a risk factor<br />
for future cardiovascular disease. 24 Although he<br />
was a smoker several years before CIN developed,<br />
we could not find any specific underlying cause for<br />
the development of the condition at the particular time<br />
of presentation. We know however that inflammatory<br />
markers have a temporal relationship to smoking, 25<br />
Clinical Medicine Insights: Case Reports 2013:6 19
Farsalinos and Romagna<br />
and this might explain the delay in CIN presentation.<br />
Cigarette smoking was suggested as a potential cause<br />
for this condition in our patient after an extensive<br />
diagnostic analysis excluded other possible conditions<br />
or intake of medications such as corticosteroids<br />
and lithium which are associated with neutrophilia. 9<br />
Despite the use of medically-approved methods, the<br />
patient failed to quit smoking. Finally, with the aid of<br />
electronic cigarettes, he was able to quit smoking in a<br />
timely manner. Five months later, CIN was reversed,<br />
although he was using the electronic cigarette on a<br />
daily basis.<br />
conclusion<br />
In conclusion, we presented a case of a young smoker<br />
having CIN and low-grade inflammation which was<br />
reversed after smoking cessation. Electronic cigarette<br />
use was successful as a smoking-cessation tool,<br />
after two failures to quit smoking (one with the use<br />
of currently-approved pharmaceutical methods). The<br />
daily use of electronic cigarettes did not hinder the<br />
beneficial effects of smoking cessation in this patient.<br />
Undoubtedly, this case report is in no way conclusive<br />
about the effects of electronic cigarettes on health.<br />
However, it indicates that research on the potential<br />
efficacy and health consequences of electronic cigarettes<br />
as a tobacco harm reduction product should be<br />
intensified. Until that time, we cannot recommend<br />
their use, but physicians will face two important ethical<br />
dilemmas in daily practice. Should they advise<br />
patients who have managed to quit smoking by using<br />
electronic cigarettes (like our patient) to stop using<br />
them, with the risk of smoking relapse? And should<br />
patients who have repeatedly failed to quit smoking<br />
by currently approved methods, such as the patient<br />
in this study, be denied the possibility, however<br />
small it may be, to quit smoking by using electronic<br />
cigarettes?<br />
Author contributions<br />
Conceived and designed the experiments: KF. Analysed<br />
the data: KF, GR. Wrote the first draft of the<br />
manuscript: KF. Contributed to the writing of the<br />
manuscript: GR. Agree with manuscript results and<br />
conclusions: KF, GR. Jointly developed the structure<br />
and arguments for the paper: KF, GR. Made<br />
critical revisions and approved final version: KF,<br />
GR. All authors reviewed and approved of the final<br />
manuscript.KF was involved in data acquisition,<br />
analysis and interpretation. GR was involved in data<br />
acquisition and was a major contributor in writing the<br />
manuscript. All authors read and approved the final<br />
manuscript.<br />
Funding<br />
Authors disclose no funding sources.<br />
competing Interests<br />
Author(s) disclose no potential conflicts of interest.<br />
Disclosures and ethics<br />
As a requirement of publication author(s) have provided<br />
to the publisher signed confirmation of compliance<br />
with legal and ethical obligations including but<br />
not limited to the following: authorship and contributorship,<br />
conflicts of interest, privacy and confidentiality<br />
and (where applicable) protection of human and<br />
animal research subjects. The authors have read and<br />
confirmed their agreement with the ICMJE authorship<br />
and conflict of interest criteria. The authors have<br />
also confirmed that this article is unique and not under<br />
consideration or published in any other publication,<br />
and that they have permission from rights holders<br />
to reproduce any copyrighted material. Any disclosures<br />
are made in this section. The external blind peer<br />
reviewers report no conflicts of interest.<br />
References<br />
1. Tonstad S, Johnston JA. Cardiovascular risks associated with smoking:<br />
a review for clinicians. Eur J Cardiovasc Prev Rehabil. 2006;13(4):<br />
507–14.<br />
2. Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking:<br />
50 years’ observations on male British doctors. BMJ. 2004;328:1519–28.<br />
3. Tverdal A, Bjartveit K. Health consequences of reduced daily cigarette<br />
consumption. Tob Control. 2006;15(6):472–80.<br />
4. Lightwood JM, Glantz SA. Short-term Economic and Health Benefits of<br />
Smoking Cessation. Circulation. 1997;96(4):1089–96.<br />
5. Taylor DH, Hasselblad V, Henley SJ, Thun MJ, Sloan FA. Benefits of<br />
smoking cessation for longevity. Am J Public Health. 2002;92(6):990–6.<br />
6. Hughes JR, Keely J, Naud S. Shape of the relapse curve and long-term<br />
abstinence among untreated smokers. Addiction. 2004;99(1):29–38.<br />
7. Rigotti NA, Pipe AL, Benowitz NL, Arteaga C, Garza D, Tonstad S. Efficacy<br />
and safety of varenicline for smoking cessation in patients with cardiovascular<br />
disease: a randomized trial. Circulation. 2010;121(2):221–9.<br />
8. Rodu B, Godshall WT. Tobacco harm reduction: an alternative cessation<br />
strategy for inveterate smokers. Harm Red J. 2006;3:37.<br />
9. Weir AB, Lewis JB Jr, Arteta-Bulos R. Chronic idiopathic neutrophilia:<br />
experience and recommendations. South Med J. 2011;104(7):499–504.<br />
10. Corre F, Lellouch J, Schwartz D. Smoking and leukocyte counts. Results of<br />
an epidemiological survey. Lancet. 1971;298(7725):632–4.<br />
11. Friedman GD, Klatsky AL, Siegelaub AB. The leukocyte count as a predictor<br />
of myocardial infarction. N Engl J Med. 1974;290(23):1275–8.<br />
20 Clinical Medicine Insights: Case Reports 2013:6
12. Imano H, Sato S, Kitamura A, et al. Leukocyte count is an independent predictor<br />
for risk of acute myocardial infarction in middle-aged Japanese men.<br />
Atherosclerosis. 2007;195(1):147–52.<br />
13. Pearson JL, Richardson A, Niaura RS, Vallone DM, Abrams DB. E-cigarette<br />
awareness, use, and harm perceptions in US adults. Am J Public Health.<br />
2012;102(9):1758–66.<br />
14. Cahn Z, Siegel M. Electronic cigarettes as a harm reduction strategy for<br />
tobacco control: a step forward of a repeat of past mistakes? J Public Health<br />
Policy. 2011;32:16–31.<br />
15. Polosa R, Caponnetto P, Morjaria JB, Papale G, Campagna D, Russo C.<br />
Effect of an electronic nicotine delivery device (e-Cigarette) on smoking<br />
reduction and cessation: a prospective 6-month pilot study. BMC Public<br />
Health. 2011;11:786.<br />
16. Siegel MB, Tanwar KL, Wood KS. Electronic cigarettes as smoking- cessation<br />
tool: results of an online survey. Am J Prev Med. 2011;40(4):472–5.<br />
17. Romagna G, Allifranchini E, Bocchieto E, Todeshi S, Esposito M,<br />
Farsalinos K. Cytotoxicity of electronic cigarette vapor extract on cultured<br />
mammalian fibroblasts (ClearStream-Life project): comparison with tobacco<br />
smoke extract [abstract]. [http://www.srnteurope.org/assets/Abstract-Book-<br />
Final.pdf.] Poster RRP17. 14th Annual Meeting of the Society for Research<br />
on Nicotine and Tobacco, Helsinki; 2012 (Accessed Nov 2012).<br />
18. Vardavas CI, Anagnostopoulos N, Kougias M, Evangelopoulou V,<br />
Connolly GN, Behrakis PK. Short-term pulmonary effects of using an<br />
electronic cigarette. Chest. 2012;141(6):1400–6.<br />
Smoking cessation by e-cigarette relieves chronic idiopathic neutrophilia<br />
19. Flouris AD, Poulianiti KP, Chorti MS, et al. Acute effects of electronic and<br />
tobacco cigarette smoking on complete blood count. Food Chem Toxicol.<br />
2012;50(10):3600–3.<br />
20. Farsalinos K, Tsiapras D, Kyrzopoulos S, et al. Acute effects of using an<br />
electronic nicotine-delivery device (e-cigarette) on myocardial function:<br />
comparison with the effects of regular cigarettes [abstract]. Eur Heart J.<br />
2012;33(Suppl):203.<br />
21. Gonçalves RB, Coletta RD, Silvério KG, et al. Impact of smoking on<br />
inflammation: overview of molecular mechanisms. Inflamm Res. 2011;<br />
60(5):409–24.<br />
22. Ambrose JA, Barua RS. The pathophysiology of cigarette smoking and<br />
cardiovascular disease: an update. J Am Coll Cardiol. 2004;43(10):1731–7.<br />
23. Tracy RP, Psaty BM, Macy E, et al. Lifetime smoking exposure affects the<br />
association of C-reactive protein with cardiovascular disease risk factors<br />
and subclinical disease in healthy elderly subjects. Arterioscler Thromb<br />
Vasc Biol. 1997;17(10):2167–76.<br />
24. Ridker PM, Cushman M, Stampfer MJ, Tracy RP, Hennekens CH.<br />
Inflammation, Aspirin, and the Risk of Cardiovascular Disease in Apparently<br />
Healthy Men. N Engl J Med. 1997;336(14):973–9.<br />
25. Bakhru A, Erlinger TP. Smoking cessation and cardiovascular disease risk<br />
factors: results from the third national health and nutrition examination<br />
survey. PLoS Med. 2005;2:e160.<br />
Clinical Medicine Insights: Case Reports 2013:6 21
Nachschlagewerk zum Thema E-Zigaretten<br />
41 Does e-cigarette consumption cause passive<br />
vaping.
Elektronische Zigarette auf dem Prüfstand<br />
Elektronische Zigaretten erleben derzeit einen Boom. Bereits zwei Millionen Deutsche<br />
sollen Schätzungen zufolge schon zu dem Dampfgerät greifen, das für viele als gesunde<br />
Alternative zum Glimmstängel gilt. Zahlreiche Stimmen – vor allem aus der Politik –<br />
warnen jedoch vor möglichen Gesundheitsrisiken, Langzeitfolgen seien noch gar nicht<br />
absehbar. Bislang vorliegende Untersuchungen kommen zu unterschiedlichen Bewertungen.<br />
Fundierte Fakten fehlen und so streiten sich Befürworter und Gegner weiterhin<br />
vehement. Mit einer neuen, unabhängigen Studie wollen Forscher des Fraunhofer-<br />
Instituts für Holzforschung WKI in Braunschweig zu einer Versachlichung dieser emotional<br />
geführten Diskussionen beitragen. Ziel der Wissenschaftler war es, herauszufi nden,<br />
ob E-Zigaretten die Raumluft belasten und somit auch Dritte beeinträchtigen können.<br />
Eine E-Zigarette besteht aus einem Akku, einem Verdampfer, einer Heizspirale sowie<br />
einem Depot mit den Betriebsfl üssigkeiten, auch Liquids genannt. Letztere werden im<br />
Verdampfer erhitzt und bei 65 bis 120 Grad Celsius verdampft. Diesen Mechanismus<br />
aktiviert der Konsument – je nach Design des Geräts – per Tastendruck oder durch<br />
Ansaugen. Es gibt die Liquids mit oder ohne Nikotin, zudem enthalten sie Aromenträger<br />
und Aromen wie Amaretto, Mandel, Vanille oder Apfel. Trägersubstanz ist meist<br />
Propylenglykol. Dieses Nebelfl uid sorgt auch für den sichtbaren Dampf beim Ausatmen.<br />
Im Gegensatz zur herkömmlichen Zigarette, die Tabak verbrennt und permanent<br />
qualmt, setzt das elektronische Pendant die Substanzen nur dann frei, wenn es eingeschaltet<br />
wird. Doch nicht nur darin unterscheiden sich die beiden Genussmittel, wie die<br />
Forscher vom WKI herausfanden. »Die verdampften Substanzen erzeugen in der E-Zigarette<br />
ein Aerosol aus ultrafeinen Partikeln, die beim Inhalieren in der Lunge weiter<br />
schrumpfen. Die Nanotröpfchen lösen sich mit der Zeit auf. Beim Verbrennungsprozess<br />
hingegen werden feste Partikel freigesetzt, die sich in der Raumluft lange halten<br />
können«, sagt Dr. Tobias Schripp, Wissenschaftler am WKI und Mitautor der Studie.<br />
Formaldehyd wird nicht freigesetzt<br />
Im Rahmen verschiedener Emissionsprüfkammermessungen analysierten die Experten<br />
die Freisetzung von fl üchtigen organischen Verbindungen (VOCs, kurz für Volatile<br />
Organic Compounds), von ultrafeinen Partikeln und von Formaldehyd. Dabei untersuchten<br />
sie unter anderem die Menge, Konzentration und Verteilung der Partikel. Hierfür<br />
führten sie in einer 8-Kubikmeter-Prüfkammer Probandentests durch, wobei konventionelle<br />
und E-Zigaretten mit unterschiedlichen Liquids miteinander verglichen wurden.<br />
Um zu ermitteln, wie sich die Partikelverteilung über mehrere Minuten entwickelt<br />
und welche Mengen an Propylenglykol über einen längeren Zeitraum freigesetzt werden,<br />
wurde das Aerosol beziehungsweise der Dampf zudem direkt in eine 10-Liter-<br />
Glaskammer gepumpt. Dieser Test erfolgte mit unterschiedlichen E-Zigaretten, die<br />
jedoch alle dasselbe Liquid enthielten. »Generell waren die Emissionen an VOCs und<br />
ultrafeinen Partikeln beim Konsum von E-Zigaretten geringer als bei der klassischen<br />
FORSCHUNG KOMPAKT<br />
12 | 2012 || Thema 5
Zigarette«, sagt Schripp. Auch konnten der Forscher und sein Team bei E-Zigaretten<br />
keine Freisetzung von Formaldehyd nachweisen. Beim herkömmlichen Glimmstängel<br />
hingegen wurde der Richtwert von 0,1 ppm (parts per million) für die Innenraumluft<br />
überschritten. Das Nebelfl uid Propylenglykol entwich aus E-Zigarette sowie Tabakzigarette<br />
in die Raumluft, da es ebenfalls ein häufi g verwendeter Zusatzstoff im Tabak ist.<br />
Lungenärzte befürchten, dass das Vernebelungsmittel beim Einatmen in großer Menge<br />
die Atemwege reizen kann. »Die elektronische Zigarette ist eine schwächere Quelle für<br />
Raumluftverunreinigungen als die Tabakzigarette, allerdings ist auch sie nicht emissionsfrei.<br />
Man kann daher davon ausgehen, dass Umstehende dem freigesetzten Dampf<br />
ausgesetzt sind und somit »Passivdampfen« möglich ist«, resümiert Schripp die Ergebnisse<br />
der Messungen. Zu monieren sei zudem die in vielen Fällen ungenaue und<br />
unzureichende Deklaration der Liquids. Gesicherte Informationen, welche Stoffe er<br />
inhaliere und ausatme, habe ein E-Raucher im Einzelfall oft nicht.<br />
Mit der Studie wollen die Wissenschaftler orientierende Messwerte für weitere Untersuchungen<br />
vorlegen. »Eine toxikologische Einschätzung liefern wir damit jedoch nicht«,<br />
betont Schripp. Die Messergebnisse wurden in der Zeitschrift »Indoor Air« veröffentlicht<br />
(http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0668.2012.00792.x/pdf). Am 6.<br />
Dezember 2012 wollen die Forscher die Studie auf der 10. Deutschen Konferenz für<br />
Tabakkontrolle vorstellen.<br />
E-Zigaretten gibt es in unterschiedlichsten<br />
Ausführungen.<br />
Ihnen allen ist jedoch eines<br />
gemein: Sie dampfen nur, wenn<br />
sie eingeschaltet sind. (© Fraunhofer<br />
WKI) | Bild in Farbe und<br />
Druckqualität: www.fraunhofer.<br />
de/presse<br />
Fraunhofer-Institut für Holzforschung – Wilhelm-Klauditz-Institut WKI | Bienroder Weg 54E | 38108 Braunschweig | www.wki.fraunhofer.de<br />
Kontakt: Dr. Tobias Schripp | Telefon +49 531 2155-249 | tobias.schripp@wki.fraunhofer.de<br />
Presse: Simone Peist | Telefon +49 531 2155-208 | simone.peist@wki.fraunhofer.de
Nachschlagewerk zum Thema E-Zigaretten<br />
42 Artikel Greek study finds e-cigarettes no threat<br />
to heart.
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Electronic Cigarettes Not Linked To Heart Damage<br />
Editor's Choice<br />
Main Category: Smoking / Quit Smoking<br />
Also Included In: Heart Disease<br />
Article Date: 27 Aug 2012 - 3:00 PST<br />
email to a friend printer friendly opinions<br />
Using electronic cigarettes is not<br />
associated with acute adverse effects<br />
on cardiac function, researchers from the<br />
Onassis Cardiac Surgery Center, Athens,<br />
Greece, reported at the European Society<br />
for Cardiology 2012 Conference in Munich,<br />
Germany. Dr Konstantinos Farsalinos added<br />
that according to currently available data,<br />
electronic cigarettes are considerably<br />
less harmful than smoking tobacco, and<br />
switching from smoking tobacco to<br />
using electronic cigarettes is most<br />
likely a good health move.<br />
According to the World Health Organization<br />
WHO), smoking will have caused over 1<br />
billion deaths by the end of this century. It is<br />
the most preventable risk factor for lung and<br />
cardiac disease. Electronic cigarette<br />
manufacturers and sellers have been<br />
promoting the product as a safer alternative for regular smokers. Millions of people worldwide<br />
regularly use electronic cigarettes today.<br />
An electronic cigarette mimics the sensations and actions experienced by tobacco smoking, but<br />
instead of breathing in smoke, the user inhales vapor. The device contains a cartridge filled<br />
with liquid, a heating element to evaporate the liquid, and a battery.<br />
Previous studies have shown that electronic cigarettes contain fewer toxins than tobacco<br />
cigarettes. The majority of studies have not detected nitrosamines in electronic cigarettes.<br />
(tobacco-specific) Nitrosamines form part of an important group of carcinogens in tobacco<br />
products. The few that did detect nitrosamines in the devices reported levels 500 to 1,400 less<br />
than what most cigarettes contain. In order to breathe in the nitrosamines contained in one<br />
tobacco cigarette, an electronic cigarette user would need to use his/her device every day for<br />
4 to 12 months.<br />
Regular tobacco smoking is associated with<br />
heart disease and death; 40% of smoking-<br />
related mortality is due to just coronary<br />
artery disease. Dr. Farsalinos and team set<br />
out to determine what acute effects<br />
electronic cigarettes might have on cardiac<br />
function.<br />
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As electronic cigarettes are marketed<br />
specifically at tobacco smokers as a<br />
healthier option, the scientists wanted to<br />
compare their results against the acute<br />
effects of tobacco cigarettes on cardiac<br />
function.<br />
Studies had already shown that inhaling tobacco smoke produces immediate defects in<br />
myocardial function. This probably means that healthy young regular tobacco smokers with no<br />
current symptoms may already have sustained some type of subclinical dysfunction.<br />
The team wanted to see whether the signs detected in tobacco smokers were also present in<br />
regular electronic cigarette users.<br />
Their study involved 42 volunteers - 20 healthy regular smokers aged 25 to 45 years and 22<br />
regular electronic cigarette users of the same age. Both groups were tested before and after<br />
smoking one tobacco cigarette or using an electronic cigarette for seven minutes.<br />
Dr. Farsalinos explained that they only used experience electronic cigarette users, because<br />
they tend to use the device more intensely.<br />
Those in the electronic cigarette group had cartridges with a solution of nicotine (concentration<br />
11mg/ml). An independent toxicology lab was used to test the solution - they found no traces of<br />
nitrosamines or polycyclic aromatic hydrocarbons.<br />
Echocardiography, blood pressure, and heart rates were examined to determine myocardial<br />
function.<br />
The scientists found that:<br />
After smoking one tobacco cigarette, acute myocardial dysfunction was clearly detected<br />
After using an electronic cigarette for 7 minutes, no adverse effects on cardiac function<br />
were detected<br />
After smoking a single tobacco cigarette, heart rate and diastolic blood pressure both went<br />
up considerably<br />
Using an electronic cigarette for 7 minutes raised diastolic blood pressure very slightly.<br />
Dr Farsalinos said:<br />
"This is an indication that although nicotine was present in the liquid used<br />
(11mg/ml), it is absorbed at a lower rate compared to regular cigarette smoking."<br />
The ultrasound scan (echocardiography examination) looked at how effectively the heart<br />
pumps blood to the whole body - it focused on the left ventricle of the heart. The left ventricle<br />
receives oxygen-rich blood from the lungs (diastolic phase) and pumps out blood (systolic<br />
phase).<br />
The researchers found that:<br />
Left ventricular function after smoking one tobacco cigarette was significantly undermined.<br />
The echocardiography exam detected four parameters which indicate worsening function.<br />
Left ventricular function after using an electronic cigarette for 7 minutes was not<br />
significantly worsened.<br />
Dr Farsalinos said:<br />
"Diastolic dysfunction is very important because it is usually the first defect that is<br />
detected before any clinically-evident cardiac disease develops.<br />
E-cigarette users can choose to inhale vaporized nicotine or<br />
non-nicotine vaporized solutions.<br />
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http://www.medicalnewstoday.com/articles/249488.php 3/5<br />
It is too early to say whether the electronic cigarette is a revolution in tobacco harm<br />
reduction but the potential is there. It is the only available product that deals with<br />
both the chemical (nicotine delivery) and psychological (inhaling and exhaling<br />
'smoke', holding it, etc) addiction to smoking, laboratory analyses indicate that it is<br />
significantly less toxic and our study has shown no significant defects in cardiac<br />
function after acute use.<br />
More clinical studies need to be done before suggesting that this is a revolutionary<br />
product. However, considering the extreme hazards associated with cigarette<br />
smoking, currently available data suggest that electronic cigarettes are far less<br />
harmful and substituting tobacco with electronic cigarettes may be beneficial to<br />
health."<br />
What are electronic cigarettes?<br />
Electronic cigarettes, also known as E-cigarettes or vaporizer cigarettes are cigarette-<br />
like devices that emit vapor instead of smoke. The user sucks and inhales the vapor just as<br />
he/she would with a tobacco product. The device is powered by a small battery.<br />
The e-cigarette user can inhale vaporized nicotine or non-nicotine vaporized solutions.<br />
Tobacco smoke is known to have over 4,000 different types of chemicals, a high proportion of<br />
which are bad for human health.<br />
Electronic cigarette makers, and a growing number of users say the device provides a very<br />
similar sensation to inhaling tobacco smoke. However, as there is no combustion, no harmful<br />
smoke is inhaled.<br />
Written by Christian Nordqvist<br />
Copyright: Medical News Today<br />
Not to be reproduced without permission of Medical News Today<br />
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Marlboro kills, not e-cigarettes<br />
posted by Hannu Vierola on 28 Aug 2012 at 5:57 am<br />
That´s true.<br />
E-cig does not. But more research needed.<br />
| post followup | alert a moderator |<br />
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E-cig study<br />
posted by Mike Morgan on 27 Aug 2012 at 4:56 am<br />
Good news for electronic cigarettes that can help avoid tobacco and reduce nicotine<br />
| post followup | alert a moderator |<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
43 Nicotine itself is not addictive.
Behavioral/Systems/Cognitive<br />
Inhibition of Monoamine Oxidases Desensitizes 5-HT 1A<br />
Autoreceptors and Allows Nicotine to Induce a<br />
Neurochemical and Behavioral Sensitization<br />
Christophe Lanteri, 1,2 Sandra Jimena Hernández Vallejo, 2,3 Lucas Salomon, 1,2 Emilie Lucie Doucet, 1,2 Gérard Godeheu, 1<br />
Yvette Torrens, 1 Vanessa Houades, 1 and Jean-Pol Tassin 1<br />
1 Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7148, Collège de France, and 2 Université Pierre et Marie Curie, Université Paris 06,<br />
F-75005 Paris, France, and 3 Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S893, Equipe 9, Faculté deMédecine Pierre<br />
et Marie Curie, Site Saint Antoine, F-75012 Paris, France<br />
Although nicotine is generally considered to be the main compound responsible for addictive properties of tobacco, experimental data<br />
indicate that nicotine does not exhibit all the characteristics of other substances of abuse. We recently showed that a pretreatment with<br />
mixed irreversible monoamine oxidases inhibitors (MAOIs), such as tranylcypromine, triggers a locomotor response to nicotine in mice<br />
and allows maintenance of behavioral sensitization to nicotine in rats. Moreover, we showed by microdialysis in mice that behavioral<br />
sensitization induced by compounds belonging to main groups of drugs of abuse, such as amphetamine, cocaine, morphine, or alcohol,<br />
was underlain by sensitization of noradrenergic and serotonergic neurons. Here, this neurochemical sensitization was tested after<br />
nicotine, tranylcypromine, or a mixture of both compounds. Data indicate that, whereas neither repeated nicotine nor repeated tranylcypromine<br />
alone has any effect by itself, a repeated treatment with a mixture of nicotine and tranylcypromine induces both behavioral<br />
sensitization and sensitization of noradrenergic and serotonergic neurons. The development of neurochemical and behavioral sensitizations<br />
is blocked by prazosin and SR46349B [(1Z,2E)-1-(2-fluoro-phenyl)-3-(4-hydroxyphenyl)-prop-2-en-one-O-(2-dimethylaminoethyl)-oxime<br />
hemifumarate], two antagonists of 1b-adrenergic and 5-HT2A receptors, respectively, but not by SCH23390 [R()-7chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine<br />
hydrochloride], a D1 receptor antagonist. Finally, we found<br />
that pretreatments with WAY 100635 [N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclo-hexane carboxamide trihydrochloride],<br />
a 5-HT1A receptor antagonist, can also induce a behavioral and neurochemical sensitization to repeated nicotine. Complementary<br />
experiments with 8-OHDPAT (8-hydroxy-dipropylamino-tetralin), a 5-HT1A receptor agonist, and analysis of 5-HT1A receptors<br />
expression in the dorsal raphe nucleus after a tranylcypromine injection indicate that MAOIs contained in tobacco desensitize<br />
5-HT1A autoreceptors to trigger the strong addictive properties of tobacco.<br />
Key words: 5-HT2A serotonergic receptor; 1b-adrenergic receptor; nicotine; tranylcypromine; microdialysis; 5-HT1A receptor<br />
Introduction<br />
Tobacco is a potent reinforcing agent in humans, and nicotine is<br />
generally considered to be the major compound responsible for<br />
its addictive properties (Dani and Heinemann, 1996; Balfour et<br />
al., 1998; Di Chiara, 2000). However, animal experiments indicate<br />
some discrepancies between the effects of nicotine and those<br />
Received July 16, 2008; revised Dec. 15, 2008; accepted Dec. 15, 2008.<br />
This work was supported by Institut National de la Santé et de la Recherche Médicale and Université Pierre et<br />
Marie Curie, and C.L. and L.S. have received a fellowship from the Mission Interministérielle de Lutte Contre la<br />
Drogue et la Toxicomanie and Ministère de la Recherche et de la Technologie, respectively. We thank Drs. Joëlle<br />
Adrien, Edith Doucet, Laurence Lanfumey, and Michel Hamon for the 5-HT 1A and 5-HTT antibodies, for their advice<br />
in the determination of 5-HT 1A receptor desensitization, and for the gift of mice depleted in 5-HT 1A receptors. We<br />
thank Drs. Véronique Béréziat, Sakina Mhaouty-Kodja, and Sébastien Parnaudeau for their precious advice on<br />
protein membrane fractioning and Western blotting. We thank Patricia Cougnot and Robert Poulhe for skillful<br />
technical assistance.<br />
Correspondence should be addressed to Jean-Pol Tassin, Centre National de la Recherche Scientifique, Unité<br />
Mixte de Recherche 7148, Collège de France, 11, Place Marcelin Berthelot, 75231 Paris Cedex 05, France. E-mail:<br />
jean-pol.tassin@college-de-france.fr.<br />
DOI:10.1523/JNEUROSCI.3315-08.2009<br />
Copyright © 2009 Society for Neuroscience 0270-6474/09/290987-11$15.00/0<br />
The Journal of Neuroscience, January 28, 2009 • 29(4):987–997 • 987<br />
of other drugs of abuse. For example, although psychostimulants<br />
and opiates induce a substantial locomotor hyperactivity both in<br />
rats and mice, nicotine is a weak locomotor stimulant in rats and<br />
fails to induce locomotor hyperactivity in mice with the exception<br />
of C3H strain (Marks et al., 1983; Kita et al., 1988; Smolen et<br />
al., 1994; Itzhak and Martin, 1999). Moreover, repeated nicotine<br />
treatments in rats induce a behavioral sensitization that vanishes<br />
quicker than for other drugs of abuse (Ksir et al., 1985; Villégier et<br />
al., 2003).<br />
Different studies have indicated that tobacco smokers have<br />
decreased brain levels of monoamine oxidases (Berlin et al., 1995;<br />
Fowler et al., 1996). Actually, tobacco and tobacco smoke contain<br />
monoamine oxidases inhibitors (MAOIs) (Poindexter and Carpenter,<br />
1962; Breyer-Pfaff et al., 1996; Rommelspacher et al.,<br />
2002). A few years ago, we showed that MAOI pretreatment allows<br />
the maintenance of behavioral sensitization to nicotine in<br />
rats (Villégier et al., 2003), thus suggesting a role of MAOIs in the<br />
addictive properties of tobacco. Later, it was found that a pretreatment<br />
with tranylcypromine, a potent and irreversible
988 • J. Neurosci., January 28, 2009 • 29(4):987–997 Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons<br />
MAOI, could trigger a locomotor and rewarding response to nicotine<br />
in mice (Villégier et al., 2006b) and dramatically increase<br />
nicotine self-administration in rats (Guillem et al., 2005; Villégier<br />
et al., 2006a).<br />
More recently, we showed that repeated injections of drugs of<br />
abuse such as D-amphetamine, cocaine, morphine, or alcohol in<br />
C57BL/6 mice induce a long-lasting sensitization of noradrenergic<br />
and serotonergic neurons (Salomon et al., 2006; Lanteri et al.,<br />
2008). The reactivity of noradrenergic and serotonergic neurons<br />
was tested by measuring the cortical increase of extracellular norepinephrine<br />
(NE) and serotonin (5-HT) levels induced by an<br />
injection of D-amphetamine or para-chloroamphetamine (PCA),<br />
NE and 5-HT releasers, respectively (Salomon et al., 2006). The<br />
development of this hyperreactivity is unrelated to dopaminergic<br />
transmission (Lanteri et al., 2008) but needs the repeated stimulation<br />
of 1b-adrenergic and 5-HT 2A receptors (Salomon et al.,<br />
2006; Lanteri et al., 2008). This neurochemical sensitization,<br />
which seems specific to addictive compounds, is strongly correlated<br />
with the sensitization of the behavioral response. For this<br />
reason, we proposed this neurochemical sensitization as a common<br />
physiological basis in the pathology of addiction (Lanteri et<br />
al., 2008; Tassin, 2008).<br />
Because addictive properties of nicotine remain controversial,<br />
we tested whether a repeated treatment with nicotine could also<br />
sensitize noradrenergic and serotonergic neurons and whether an<br />
association of nicotine with tranylcypromine could trigger the<br />
same neurochemical and behavioral adaptations induced by psychostimulants,<br />
opiates, and ethanol. Furthermore, because tranylcypromine<br />
appeared necessary in the development of behavioral<br />
and neurochemical sensitizations to nicotine, we tried to<br />
understand why, in our experimental model in mice, repeated<br />
injections of nicotine alone do not induce these sensitizations.<br />
Our data suggest that nicotine induces an indirect stimulation of<br />
5-HT 1A autoreceptors that limits serotonergic transmission and<br />
that desensitization of 5-HT 1A autoreceptors by MAOIs removes<br />
this limitation.<br />
Materials and Methods<br />
Subjects<br />
Wild-type (WT) mice were C57BL/6J, 2–3 months of age, and male<br />
(25–35 g). They were housed four by cage and maintained on a 12 h<br />
light/dark cycle (lights on at 7:00 A.M.) with food and water available ad<br />
libitum. All animals were naive at the beginning of each experiment.<br />
Drugs<br />
()-Nicotine hydrogen tartrate, tranylcypromine hydrochloride,<br />
D-amphetamine sulfate p-chloroamphetamine hydrochloride, N-[2-[4-<br />
(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclo-hexane<br />
carboxamide trihydrochloride (WAY 100635) and 8-hydroxy-dipropylamino-tetralin<br />
(8-OHDPAT) (Sigma Aldrich) were dissolved in saline.<br />
The pH values of the solutions were adjusted to 7.4 with 1N NaOH.<br />
Prazosin hydrochloride (Sigma-Aldrich) was sonicated in water and<br />
completed with saline. (1Z,2E)-1-(2-Fluoro-phenyl)-3-(4hydroxyphenyl)-prop-2-en-one-O-(2-dimethylamino-ethyl)-oxime<br />
hemifumarate (SR46349B hemifumarate) was a generous gift from<br />
sanofi-aventis. It was dissolved with a drop of lactic acid, neutralized with<br />
1 M NaOH, and sonicated in saline. R()-7-Chloro-8-hydroxy-3methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine<br />
hydrochloride<br />
(SCH23390 hydrochloride) (Sigma Aldrich) was first dissolved in distilled<br />
water, which was then completed with saline. All drugs were injected<br />
intraperitoneally (0.3 ml per 100 g) except for nicotine, which was<br />
injected subcutaneously (0.15 ml per 100 g). Tetrodotoxin (TTX) (Tocris<br />
Bioscience) was perfused through the membrane dialysis at a concentration<br />
of 1 M. Doses are expressed as salts. D-Amphetamine was given at 2<br />
mg/kg and p-chloroamphetamine at 7 mg/kg (Itzhak et al., 2004). Doses<br />
of prazosin (1 mg/kg, i.p.) and SR46349B (1 mg/kg, i.p.) were kept iden-<br />
tical with previous experiments (Auclair et al., 2004). Doses of nicotine (1<br />
mg/kg, s.c.; salt instead of base) and tranylcypromine (6 mg/kg instead of<br />
10 mg/kg) were decreased because of repeated treatments (Villégier et al.,<br />
2006a). SCH23390 was used at 0.2 mg/kg (intraperitoneally), a dose<br />
which blocks the development of behavioral and neurochemical sensitization<br />
to 2 mg/kg D-amphetamine (Salomon et al., 2006). WAY 100635<br />
and 8-OHDPAT were injected at a dose of 1 mg/kg.<br />
Surgery<br />
Mice were anesthetized with sodium pentobarbital (60 mg/kg; Sanofi<br />
Santé Animale) and placed in a stereotaxic frame (Kopf Instruments).<br />
Unilateral permanent cannula (CMA/7 guide cannula; Microdialysis)<br />
was placed at the edge of the prefrontal cortex (PFC) and was secured on<br />
the skull with screw and dental cement. The coordinates for the guide<br />
cannula tip were as follows: anteroposterior, 2.6 relative to bregma;<br />
mediolateral, 0.5; and dorsoventral, 0 mm from dura (Salomon et al.,<br />
2006). After surgery, mice were placed in individual plastic cages and<br />
allowed to recover for at least 4 d.<br />
Microdialysis experiments<br />
Acute treatment. The day of the experiment, the microdialysis probe was<br />
inserted in the PFC (CMA/7; membrane length, 2 mm, and diameter,<br />
0.24 mm; cutoff, 6000 Da; Microdialysis). Artificial CSF (in mM: 147<br />
NaCl, 3.5 KCl, 1 CaCl 2, 1.2 MgCl 2, 1 NaH 2PO 4, 25 NaHCO 3, pH 7.6) was<br />
perfused with a CMA100 microinjection pump through the probe at a<br />
rate of 1 l/min via FEP catheter (internal diameter, 0.12 mm) connected<br />
to a fluid swivel. Adequate steady state of monoamines levels in perfusate<br />
samples was reached 140 min after probe insertion, and samples were<br />
collected in 300 l vials placed into a refrigerated computer-controlled<br />
fraction collector (CMA/170). Samples (20 l every 20 min) were collected<br />
during 100 min, to determine basal extracellular values. After<br />
D-amphetamine or PCA injections, samples were collected for 200 min.<br />
After tranylcypromine injection, samples were collected for 240 min. In<br />
the last series of experiments, 100 min after tranylcypromine injection,<br />
either 8-OHDPAT (0.5 mg/kg) was injected systemically, or TTX (1 M)<br />
was perfused locally through the probe. Samples were analyzed for NE or<br />
5-HT levels the day of the experiment.<br />
Repeated treatment. The experimental conditions are shown in Table<br />
1. Briefly, mice received four consecutive daily injections of saline or<br />
tranylcypromine or nicotine or tranylcypromine plus nicotine or WAY<br />
100635 or WAY 100635 plus nicotine and waited 4 d before the dialysis<br />
experiment. To test the effect of the pretreatment on the development of<br />
neurochemical sensitization to tranylcypromine plus nicotine, mice received<br />
every single day a pretreatment (saline or prazosin plus SR46349B<br />
or SCH23390) 30 min before the injection of tranylcypromine. When<br />
animals were pretreated with prazosin and SR46349B, two subsequent<br />
injections of prazosin were administered at 60 and 150 min after tranylcypromine<br />
injection, because of its short half-life (100 min) (Auclair et<br />
al., 2004). Every day after drug injection, mice were immediately placed<br />
for2hinthecylindrical compartment used to perform microdialysis.<br />
Control mice were injected on 4 consecutive days with 0.9% saline (0.1<br />
ml/injection) or SR46349B plus prazosin or SCH23390, and their response<br />
to D-amphetamine or PCA was measured 4 d later.<br />
Biochemistry<br />
Dialysate samples were completed to 30 l with the adapted mobile phase<br />
and placed into a refrigerated automatic injector (Triathlon; Spark Holland).<br />
Twenty-five microliters of the sample were injected every 30 min<br />
through a rheodyne valve in the mobile phase circuit. High-performance<br />
liquid chromatography was performed with a reverse-phase column<br />
(80 4.6 mm; 3 m particle size; HR-80; ESA). Mobile phase (for NE<br />
analysis: 0.1 M NaH 2PO 4, 0.1 mM EDTA, 3.8 mM octane sulfonic acid,<br />
0.25 mM triethylamine, 10% methanol, pH 2.9; and for 5-HT analysis: 0.1<br />
M NaH 2PO 4, 0.1 mM EDTA, 1.5 mM octane sulfonic acid, 0.25 mM triethylamine,<br />
15% methanol, 5% acetonitrile, pH 2.9) was delivered at 0.7<br />
ml/min by an ESA-580 pump. Electrochemical detection was performed<br />
with an ESA coulometric detector (Coulochem II 5100A, with a 5014B<br />
analytical cell; Eurosep). The conditioning electrode was set at 0.175<br />
mV, and the detecting electrode was set at 0.175 mV, allowing a good
Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons J. Neurosci., January 28, 2009 • 29(4):987–997 • 989<br />
Table 1. Mice pretreatments before challenges by D-amphetamine or para-chloro-amphetamine<br />
Day 1 Day 2 Day 3 Day 4 Days 5–8 Day 9<br />
Saline Saline Saline Saline 4 d Withdrawal D-Amph<br />
Id Id Id Id Id PCA<br />
Tranyl Tranyl Tranyl Tranyl Id D-Amph<br />
Id Id Id Id Id PCA<br />
Nicotine Nicotine Nicotine Nicotine Id D-Amph<br />
Id Id Id Id Id PCA<br />
Tranyl nico Tranyl nico Tranyl nico Tranyl nico Id D-Amph<br />
Id Id Id Id Id PCA<br />
SR/Pz tranyl nico SR/Pz tranyl nico SR/Pz tranyl nico SR/Pz tranyl nico Id D-Amph<br />
Id Id Id Id Id PCA<br />
SCH tranyl nico SCH tranyl nico SCH tranyl nico SCH tranyl nico Id D-Amph<br />
Id Id Id Id Id PCA<br />
Way nico Way nico Way nico Way nico Id D-Amph<br />
In order to test neurochemical and behavioral sensitizations, mice received once a day during 4 d different pretreatments beforea4dwithdrawal. Way, WAY 100635; SCH, SCH23390; D-Amph, D-amphetamine; nico, nicotine; tranyl,<br />
tranylcypromine; Id, idem; Pz, prazosin; SR, SR46349B.<br />
signal-to-noise ratio. External standards were regularly injected to determine<br />
the stability of the sensitivity (0.2 pg for NE and 0.3 pg for 5-HT).<br />
Locomotor activity<br />
Acute treatment. Mice were introduced in a circular corridor (4.5 cm<br />
width, 17 cm external diameter) crossed by four infrared beams (1.5 cm<br />
above the base) placed at every 90° (Imetronic). The locomotor activity<br />
was counted when animals interrupted two successive beams and thus<br />
had traveled one-quarter of the circular corridor. Spontaneous activity<br />
was recorded for 120 min (habituation to the experimental procedure),<br />
and then mice were injected intraperitoneally with D-amphetamine or<br />
p-chloroamphetamine or tranylcypromine or nicotine or tranylcypromine<br />
plus nicotine or WAY 100635 or WAY 100635 plus nicotine or<br />
8-OHDPAT or 8-OHDPAT plus nicotine, and locomotor responses were<br />
recorded for an additional 200 min period. Injection of nicotine occurred<br />
100 min after injection of tranylcypromine (Villégier et al., 2006a), 30<br />
min after injection of WAY 100635, and 60, 100, or 120 min after injection<br />
of 8-OHDPAT.<br />
Repeated treatment. The experimental conditions are shown in Table<br />
1. Briefly, mice received four consecutive daily injections of saline or<br />
tranylcypromine or nicotine or tranylcypromine plus nicotine, or WAY<br />
100635 or WAY 100635 plus nicotine, and their locomotor activity was<br />
recorded after a D-amphetamine, p-chloroamphetamine, or WAY<br />
100635 plus nicotine injection after a4dwithdrawal with the same<br />
protocol as for an acute treatment. To test the effect of the pretreatment<br />
on the development of behavioral sensitization to tranylcypromine plus<br />
nicotine, mice received every single day a pretreatment (saline or prazosin<br />
plus SR46349B or SCH23390) 30 min before the injection of tranylcypromine.<br />
When animals were pretreated with prazosin plus SR46349B,<br />
two subsequent injections of prazosin were administered at 60 and 150<br />
min after tranylcypromine injection because of its short half-life (100<br />
min). Finally, locomotor responses to D-amphetamine or PCA were<br />
tested 4 d after the last drug injection. Control mice were injected on 4<br />
consecutive days with saline or SR46349B plus prazosin or SCH23390,<br />
and their locomotor response to D-amphetamine or PCA was recorded<br />
4 d later.<br />
Histology<br />
At the end of the experiment, brains were put into a formaldehyde solution<br />
and cut on a microtome in serial coronal slices according to the atlas<br />
of Paxinos and Franklin (1997). Histological examination of cannula tip<br />
placement was subsequently made on 100 m safranine-stained coronal<br />
sections (Fig. 1).<br />
Immunodetection of 5-HT 1A receptors<br />
Preparation of membrane protein enriched fraction. Mice were injected<br />
with saline or tranylcypromine (6 mg/kg, i.p.) in their home cage. Onehundred<br />
minutes later, they were killed by decapitation, and their brains<br />
were rapidly removed from the calvarium and immediately frozen in<br />
isopentane (30°C), before being stored at 80°C. Then, serial coronal<br />
sections (500 m) were obtained using a cryostat (MICROM HM560).<br />
Figure 1. Schematic illustration of the localization of the membrane dialysis. The drawing is<br />
from the atlas by Paxinos and Franklin (1997). The number corresponds to the anteriority of the<br />
slice from the bregma.<br />
One hundred milligrams of prefrontal cortex (corresponding to four<br />
mice in each group) were collected and 50 mg of dorsal raphe nucleus<br />
(DRN) (corresponding to eight mice in each group) were punched from<br />
the slices according to the atlas of Paxinos and Franklin (1997). These<br />
experiments were performed at 20°C.<br />
The prefrontal cortex and DRN punched samples were homogenized<br />
using a1mlPotter-Elvehjem PTFE pestle and glass tube homogenizer<br />
(Sigma-Aldrich), (1 g/10 V), in ice-cold classic Tris-HCl buffer (10 mM,<br />
pH 8; Sigma-Aldrich) containing 0.25 M sucrose and Protease Inhibitor<br />
Mixture tablet (Roche Diagnostics). These homogenates were centrifuged<br />
at 22,000 g for 10 min at 4°C. The supernatants were carefully<br />
decanted, and then centrifuged at 50,000 g for1hat4°C. The supernatants<br />
resulting of this second centrifugation were removed, and the<br />
remaining pellets containing membrane proteins were finally resuspended<br />
in 50 l of homogenized buffer described above. The preparation<br />
of this membrane enriched fraction was adapted from a protocol previously<br />
described for myometrial cell membranes (Legrand et al., 1987;<br />
Mhaouty-Kodja et al., 2001).<br />
Western blot analysis. The protein concentration of all extracted samples<br />
was measured using Bio-Rad Protein Assay (Bio-Rad Laboratories)<br />
and bovine serum albumin (BSA) was used as a protein standard. Protein<br />
samples (40 g) were boiled 5 min at 95°C in Laemmli buffer containing<br />
glycerol and -mercaptoethanol (Laemmli, 1970). Lysates were subjected<br />
to SDS-PAGE and transferred on HybondC EC nitrocellulose<br />
membrane (GE Healthcare). Membranes were then blocked1hatroom
990 • J. Neurosci., January 28, 2009 • 29(4):987–997 Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons<br />
temperature in buffer containing 50 mM Tris,<br />
150 mM NaCl, 0.1% Tween 20, and 2% BSA,<br />
and incubated overnight at 4°C in a 1:500e dilution<br />
of rabbit polyclonal antibody against<br />
5-HT 1A receptor (el Mestikawy et al., 1990) or<br />
in a 1:1500e dilution of rabbit polyclonal antibody<br />
against 5-HT transporter (5-HTT) (Qian<br />
et al., 1995). Secondary antibody, goat antirabbit<br />
IgG conjugated to HRP (7074 and 7072;<br />
Cell Signaling), was used in 1:3000 dilution in<br />
TBS-Tween (0.1%) solution. Membranes were<br />
incubated1hatroom temperature, and visualization<br />
of immunoreactivity was performed by<br />
chemiluminescence using ECL kit (Pierce EC<br />
Western Blotting Substrate kit; Thermo Scientific),<br />
and detection of chemiluminescence was<br />
performed using Kodak developer and fixer,<br />
and Kodak Hyperfilm ECL (GE Healthcare).<br />
Beta Actine (A544J; Sigma-Aldrich) was immunoprobed<br />
as index of cellular protein level. Immunostaining<br />
quantification was performed by<br />
using the ChemiGenius2 analyzer image and<br />
software (Ozyme). 5-HT 1A knock-out (KO)<br />
mice (Heisler et al., 1998) were used as control<br />
of antibody specificity. The 5-HTT was used as<br />
a specific marker of serotonergic cells and<br />
plasma membrane proteins.<br />
Statistics<br />
Statistical analysis was performed using Graph-<br />
Pad Prism 3.0 software. Data from microdialysis<br />
and locomotor activity experiments were described<br />
as a function of time. Data from<br />
microdialysis were expressed as a percentage of<br />
the respective mean basal value. The extracellu-<br />
lar monoamines levels and the locomotor activity obtained after different<br />
treatments were compared and analyzed with a two-way ANOVA (repeated<br />
measures). In this test, there are two factors that affect the dependent<br />
variables: effect of time (effect A) and effect of drug (effect B). Each<br />
factor has two or more levels within it, and the degrees of freedom (df) for<br />
each factor is 1 less than the number of levels. It is assumed (1) that main<br />
effect A has a levels [and A has (a 1) df], (2) that main effect B has b<br />
levels [and B has (b 1) df], and (3) that n is the sample size of each<br />
treatment. In these conditions, when there is a significant interaction<br />
between the two factors, we compare F AB to a F with (a 1) and (a <br />
1)(b 1) degrees of freedom. When there is no significant interaction,<br />
we compare F AB to a F with (a 1) and a(n 1) degrees of freedom, the<br />
residual. Differences in 5-HT 1A receptors expression were determined<br />
using an unpaired t test. Significant differences were set at p 0.05.<br />
Results<br />
Repeated nicotine alone or tranylcypromine alone leads<br />
neither to noradrenergic and serotonergic neuron<br />
sensitization nor to behavioral sensitization<br />
As previously observed (Salomon et al., 2006), repeated treatment<br />
with saline does not alter the NE and 5-HT release in the<br />
prefrontal cortex, when compared with acutely treated animals,<br />
after a D-amphetamine and PCA injection, respectively (F (1,24) <br />
2.848, p 0.1, and F (1,24) 1.696, p 0.2, respectively). Similarly,<br />
repeated treatments with nicotine do not induce increases<br />
in extracellular NE or 5-HT levels higher than those induced in<br />
animals pretreated with saline (F (1,24) 2.816, p 0.1, and F (1,24)<br />
1.149, p 0.2, for NE and 5-HT levels induced by<br />
D-amphetamine and PCA, respectively) (Fig. 2A,C). Furthermore,<br />
repeated treatments with tranylcypromine induce a slight<br />
but significant decrease in extracellular NE and 5-HT levels (F (1,5)<br />
5.224, p 0.05, and F (1,5) 7.356, p 0.01, for NE and 5-HT<br />
levels induced by D-amphetamine and PCA, respectively).<br />
Figure 2. Repeated nicotine requires tranylcypromine to sensitize noradrenergic and serotonergic neurons and obtain behavioral<br />
sensitization. Nicotine (1 mg/kg), tranylcypromine (6 mg/kg), and nicotine plus tranylcypromine were used for repeated<br />
treatments. Four days after the last injection, D-amphetamine (2 mg/kg) or PCA (7 mg/kg) was administered and cortical extracellular<br />
NE (A) or 5-HT (C) levels, respectively or locomotor responses (B, D, respectively) were analyzed. Each group contained at<br />
leastfiveanimalsformicrodialysisexperimentsandeightanimalsforlocomotoractivitydetermination.A,CorticalextracellularNE<br />
levels are expressed as a percentage of the respective mean basal value. There was no significant difference in basal cortical<br />
extracellular NE levels in the different conditions (mean basal NE values, 0.67 pg NE/20 min 0.08). B, Locomotor response to<br />
D-amphetamine (2 mg/kg) is measured in the same experimental conditions as in A. C, Cortical extracellular 5-HT levels are<br />
expressed as a percentage of the respective mean basal value. There was no significant difference in basal cortical extracellular<br />
5-HT levels in the different conditions (mean basal 5-HT values, 0.81 pg 5-HT/20 min 0.06). D, Locomotor response to PCA (7<br />
mg/kg) was measured in the same experimental conditions as in C. Error bars indicate SEM. nico, Nicotine; tranyl,<br />
tranylcypromine.<br />
Finally, repeated treatments with nicotine or tranylcypromine<br />
do not induce behavioral sensitization to D-amphetamine or PCA<br />
treatments [(F (1,147) 1.59, p 0.8, and F (1,147) 1.86, p 0.1,<br />
after D-amphetamine for repeated nicotine or tranylcypromine,<br />
respectively, when compared with repeated saline) and (F (1,147) <br />
2.975, p 0.08, and F (1,147) 0.6404, p 0.4, after PCA for<br />
repeated nicotine or tranylcypromine, respectively, when compared<br />
with repeated saline)] (Fig. 2B,D).<br />
Repeated treatments with a nicotine and tranylcypromine<br />
mixture lead to noradrenergic and serotonergic neuron<br />
sensitization and behavioral sensitization<br />
When animals received repeated treatments with both nicotine<br />
and tranylcypromine, we found an important increase in extracellular<br />
NE and 5-HT levels (F (1,5) 294.4, p 0.0001, and F (1,5)<br />
93.76, p 0.0001, for NE and 5-HT levels induced by<br />
D-amphetamine and PCA, respectively) (Fig. 2A,C). Similarly,<br />
after repeated treatments with nicotine plus tranylcypromine, we<br />
found a significant behavioral sensitization to D-amphetamine<br />
and PCA (F (1,20) 354.7, p 0.0001, and F (1,20) 224.1, p <br />
0.0001, for repeated tranylcypromine plus nicotine when compared<br />
with repeated saline, after D-amphetamine or PCA, respectively)<br />
(Fig. 2B,D).<br />
Pretreatments with prazosin and SR46349B, but not with<br />
SCH23390, before nicotine and tranylcypromine mixture<br />
injection, protect noradrenergic and serotonergic neurons<br />
from sensitization and block the development of behavioral<br />
sensitization<br />
To verify that, as in the case of other drugs of abuse, increased<br />
reactivity of noradrenergic and serotonergic neurons induced by<br />
repeated treatments with nicotine and tranylcypromine is related
Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons J. Neurosci., January 28, 2009 • 29(4):987–997 • 991<br />
Figure 3. Development of neurochemical and behavioral sensitizations induced by repeated tranylcypromine plus nicotine is<br />
blocked by prazosin and SR46349B but not by SCH23390. Experimental conditions were identical with those of Figure 2 for<br />
determinations of extracellular NE and 5-HT levels as well as for monitoring locomotor activity (A–D). Each group consisted of at<br />
leastfiveandeightanimalsformicrodialysisandlocomotoractivity,respectively.Itwasverifiedthatdataobtainedwithrepeated<br />
SR46349B plus prazosin or repeated SCH233890 were not significantly different from that of repeated saline. Amph, D-Amphetamine;<br />
SR, SR46349B; Pz, prazosin; SCH, SCH23390. Error bars indicate SEM.<br />
to the stimulation of 1b-adrenergic and 5-HT 2A receptors, prazosin<br />
(1 mg/kg) and SR46349B (1 mg/kg) were injected 30 min<br />
before tranylcypromine plus nicotine mixture. Pretreatment<br />
with these two receptor antagonists blocked the NE and 5-HT<br />
neuron sensitization induced by repeated tranylcypromine plus<br />
nicotine mixture. It was found that extracellular NE and 5-HT<br />
levels induced by D-amphetamine and PCA were significantly<br />
different between animals pretreated with tranylcypromine and<br />
nicotine and those pretreated with prazosin and SR46349B in<br />
addition to tranylcypromine and nicotine (F (1,5) 368.4, p <br />
0.0001, and F (1,5) 157.7, p 0.0001, for NE and 5-HT extracellular<br />
levels, respectively) (Fig. 3A,C). Indeed, after pretreatment<br />
with these two receptor antagonists, extracellular NE and<br />
5-HT levels induced by D-amphetamine and PCA were not different<br />
from those of animals repeatedly treated with saline (F (1,24)<br />
3.765, p 0.06, and F (1,24) 3.663, p 0.06, for NE and 5-HT<br />
levels, respectively).<br />
At the opposite, injections of a D 1 receptor antagonist,<br />
SCH23390, at 0.2 mg/kg, a dose that blocks behavioral and neurochemical<br />
sensitizations to D-amphetamine (Salomon et al.,<br />
2006), 30 min before injections of the tranylcypromine plus nicotine<br />
mixture did not modify the increased responses in extracellular<br />
NE and 5-HT levels induced by D-amphetamine and PCA in<br />
animals pretreated with saline before the tranylcypromine plus<br />
nicotine mixture (F (1,24) 0.0028, p 0.9, and F (1,24) 0.5170,<br />
p 0.4, when compared with saline-pretreated animals for NE<br />
and 5-HT levels after D-amphetamine and PCA, respectively)<br />
(Fig. 3A,C).<br />
Effects obtained for behavioral sensitizations to<br />
D-amphetamine and PCA in presence of these three receptors<br />
ligands are identical with those obtained for neurochemical sensitizations.<br />
Indeed, pretreatments with prazosin and SR46349B<br />
block the development of the behavioral sensitizations to<br />
D-amphetamine and PCA (F (1,147) 3.61, p 0.06, and F (1,147) <br />
2.765, p 0.09, for repeated tranylcypromine plus nicotine when<br />
compared with repeated saline after D-amphetamine or PCA,<br />
respectively), whereas SCH23390 has no<br />
effect on the development of behavioral<br />
sensitization to D-amphetamine and PCA<br />
induced by tranylcypromine plus nicotine<br />
(F (1,147) 3.885, p 0.06, and F (1,147) <br />
3.691, p 0.06, for D-amphetamine and<br />
PCA, respectively, when compared with<br />
animals pretreated with saline instead of<br />
SCH23390) (Fig. 3B,D).<br />
Finally, behavioral experiments were<br />
performed in presence of either prazosin<br />
(1 mg/kg) or SR46349B (1 mg/kg) to<br />
determine the respective roles of noradrenergic<br />
and serotonergic transmissions,<br />
respectively, in the development of behavioral<br />
sensitizations to repeated tranylcypromine<br />
plus nicotine. We found that<br />
each receptor antagonist (i.e., prazosin or<br />
SR46349B) was able to block almost completely<br />
the behavioral sensitizations induced<br />
by tranylcypromine plus nicotine as<br />
revealed by D-amphetamine or PCA administrations<br />
(data not shown).<br />
Effects of the acute injection of the<br />
mixture tranylcypromine plus nicotine<br />
on locomotor response and cortical<br />
extracellular NE and 5-HT levels<br />
We showed previously (Villégier et al., 2006a,b) that, whereas<br />
C57BL/6 mice do not exhibit a locomotor response to nicotine (1<br />
mg/kg; base), nicotine-induced locomotor hyperactivity could be<br />
obtained when tranylcypromine (10 mg/kg) was injected 100 min<br />
before nicotine. Here, we confirm these data when a lower dose of<br />
tranylcypromine (6 mg/kg) is injected 100 min before a lower<br />
dose of nicotine (1 mg/kg; salt) (F (1,48) 461.4, p 0.0001, when<br />
tranylcypromine plus nicotine is compared with tranylcypromine<br />
plus saline) (Fig. 4A).<br />
Because the sensitizing effects of the mixture tranylcypromine<br />
plus nicotine are blocked by 1-adrenergic and 5-HT 2A receptor<br />
antagonists, we analyzed the time course of cortical extracellular<br />
NE and 5-HT levels in the same conditions as those of the development<br />
of the locomotor response. As shown on Figure 4B, cortical<br />
extracellular NE levels increase dramatically 20 min after<br />
tranylcypromine (6 mg/kg) and then decrease regularly to attain<br />
initial values 100 min after the injection (F (1,12) 121.2, p <br />
0.0001, when compared with saline injection). Nicotine, however,<br />
has no effect on extracellular NE levels in presence or absence<br />
of tranylcypromine (F (1,52) 2.344, p 0.1, and F (1,52) <br />
3.578, p 0.06, when compared with respective controls, with<br />
saline or with tranylcypromine) (Fig. 4B).<br />
Figure 4C shows that, unlike extracellular NE levels, extracellular<br />
5-HT levels increase regularly after tranylcypromine (6 mg/<br />
kg) and increase quicker when nicotine is injected instead of<br />
saline 100 min after tranylcypromine (F (1,12) 240.8, p 0.0001,<br />
and F (1,12) 39.08, p 0.0001, when compared with saline and<br />
nicotine, respectively). Finally, it was verified that nicotine<br />
alone had no effect on cortical extracellular 5-HT levels (F (1,52)<br />
3.242; p 0.07) (Fig. 4C). It can be noted that these data<br />
obtained on cortical extracellular 5-HT levels are similar to<br />
those obtained when extracellular 5-HT levels were monitored<br />
in the nucleus accumbens after tranylcypromine and nicotine<br />
(Villégier et al., 2006a).
992 • J. Neurosci., January 28, 2009 • 29(4):987–997 Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons<br />
Figure 4. Locomotor activity and cortical extracellular NE and 5-HT levels in response to<br />
nicotine in presence or absence of tranylcypromine. Animals received tranylcypromine (6 mg/<br />
kg)orsaline(firstarrow)and,100minlater,aninjectionofnicotine(1mg/kg)orsaline(second<br />
arrow), and locomotor activity (A) and extracellular NE (B) and 5-HT (C) levels were monitored.<br />
Each group consisted of at least five and eight animals for microdialysis and locomotor activity,<br />
respectively. Mean basal cortical extracellular NE and 5-HT levels were similar to those of Figure<br />
2. Error bars indicate SEM. nico, Nicotine; tranyl, tranylcypromine.<br />
Effects of 8-OHDPAT, a 5-HT 1A receptor agonist, on<br />
locomotor response to nicotine<br />
Our data indicate that a modification of 5-HT transmission by<br />
nicotine is associated with a locomotor response to nicotine. Engberg<br />
et al. (2000) showed that nicotine could indirectly inhibit<br />
serotonergic neurons through the stimulation of 5-HT 1A receptors.<br />
We therefore made the hypothesis that tranylcypromine,<br />
because of its effects on extracellular 5-HT levels, was desensitizing<br />
5-HT 1A receptors, thus allowing nicotine to trigger a locomotor<br />
response. This was tested by pretreating the animals with<br />
8-OHDPAT (1 mg/kg), a 5-HT 1A receptor agonist, at different<br />
times before nicotine injection (1 mg/kg). Figure 5 shows that,<br />
whereas 8-OHDPAT has no effect on nicotine-induced locomotor<br />
response 60 min after the agonist injection (F (1,987) 3.09,<br />
p 0.07, when compared with saline), nicotine induces a significant<br />
locomotor response 100 min (F (1,140) 573.3; p 0.0001)<br />
as well as 120 min (F (1,140) 850.8; p 0.0001) after 8-OHDPAT<br />
injection (Fig. 5A–C).<br />
Effects of WAY 100635, a 5-HT 1A receptor antagonist, on<br />
locomotor response to nicotine<br />
To verify that the effect of 8-OHDPAT on locomotor response to<br />
nicotine was attributable to the desensitization/inactivation of<br />
5-HT 1A receptors, analysis of locomotor response to nicotine was<br />
performed in presence of WAY 100635, a 5-HT 1A receptor antagonist.<br />
Figure 6 shows that, 30 min after the injection of<br />
WAY100635, nicotine induces a significant locomotor response<br />
(F (1,60) 867.5; p 0.0001), whereas no significant effect is<br />
observed when nicotine or WAY 100635 is injected alone (F (1,427)<br />
3.341, p 0.1, and F (1,427) 0.3173, p 0.5, when compared<br />
with saline, for nicotine and WAY 100635, respectively) (Fig.<br />
6A).<br />
Interestingly, when WAY 100635 and nicotine were injected<br />
once a day on 4 consecutive days and WAY 100635 and nicotine<br />
were injected after a4dwithdrawal, a significant increase in<br />
locomotor response to nicotine is obtained (F (1,60) 812.2, p <br />
0.0001, when compared with acute locomotor response induced<br />
by WAY 100635 plus nicotine) (Fig. 6B–D). This behavioral sensitization<br />
is not observed when animals are pretreated once a day<br />
on 4 consecutive days with WAY 100635 or nicotine alone<br />
(F (1,427) 0.3173, p 0.5, and F (1,427) 0.09002, p 0.7643, for<br />
WAY 100635 and nicotine, respectively) (Fig. 6B,D).<br />
Does behavioral sensitization obtained with WAY 100635<br />
plus nicotine correlate with sensitization of noradrenergic<br />
and serotonergic neurons?<br />
To test whether behavioral sensitization to nicotine obtained<br />
with repeated injections of WAY 100635 plus nicotine was parallel<br />
to neurochemical sensitization, cortical extracellular NE and<br />
5-HT levels were monitored after D-amphetamine and PCA injections.<br />
Figure 7 shows that animals repeatedly treated with<br />
WAY 100635 and nicotine exhibit a higher increase of extracellular<br />
NE and 5-HT levels than corresponding controls (F (1,5) <br />
53.01, p 0.0001, and F (1,5) 38.33, p 0.0001, for NE and<br />
5-HT levels, respectively), whereas extracellular NE and 5-HT<br />
levels are not different from controls when animals are repeatedly<br />
treated with WAY 100635 alone (F (1,24) 0.5650, p 0.4, and<br />
F (1,24) 0.2904, p 0.5, for NE and 5-HT levels, respectively)<br />
(Fig. 7A,C). Similarly, extracellular NE and 5-HT levels are not<br />
different from controls when animals are repeatedly treated with<br />
nicotine alone (Fig. 2A,C).<br />
An increase in locomotor responses to D-amphetamine and<br />
PCA is also observed in animals repeatedly treated with WAY<br />
100635 plus nicotine (F (1,20) 295.7, p 0.0001, and F (1,20) <br />
394.7, p 0.0001, when compared with saline pretreated animals<br />
for D-amphetamine and PCA, respectively), whereas this effect is<br />
not observed in animals repeatedly treated with WAY 100635<br />
alone (F (1,147) 3.529, p 0.06, and F (1,147) 0.3204, p 0.5,<br />
for D-amphetamine and PCA, respectively) (Fig. 7B,D). Similarly,<br />
there is no effect on locomotor response when animals are<br />
repeatedly treated with nicotine alone (Fig. 2B,D).<br />
Analysis of the effects of tranylcypromine on<br />
5-HT 1A receptors<br />
To test early effects of tranylcypromine on 5-HT 1A receptor function,<br />
we analyzed by microdialysis the ability of 8-OHDPAT to<br />
decrease 5-HT extracellular levels 100 min after a tranylcypromine<br />
injection. As expected, 8-OHDPAT (0.5 mg/kg) induces a<br />
potent decrease in 5-HT extracellular levels (F (1,7) 628.5, p <br />
0.0001, when compared with saline) (Fig. 8A). In contrast, 100<br />
min after a tranylcypromine injection, 8-OHDPAT (0.5 mg/kg)<br />
fails to significantly alter 5-HT extracellular levels (F (1,32) <br />
0.8414, p 0.3, when compared with saline). Same data were<br />
obtained with 1 mg/kg 8-OHDPAT (data not shown).<br />
However, because tranylcypromine may increase 5-HT extracellular<br />
levels through an impulse-independent process that<br />
would be insensitive to 5-HT 1A receptors stimulation, the effect
Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons J. Neurosci., January 28, 2009 • 29(4):987–997 • 993<br />
Figure 5. Effects of 8-OHDPAT, a 5-HT 1A receptor agonist, on locomotor activity induced by nicotine. Three groups of eight<br />
animals received an injection of 8-OHDPAT (1 mg/kg) and 60 min (A), 100 min (B), or 120 min (C) later, an injection of nicotine (1<br />
mg/kg) or of saline, and locomotor activity was monitored. Error bars indicate SEM. nico, Nicotine.<br />
of a local perfusion of TTX was tested on the increased<br />
tranylcypromine-induced 5-HT extracellular levels. Data indicate<br />
that, when 1 M TTX is perfused through the dialysis probe<br />
100 min after a tranylcypromine injection, it induces a dramatic<br />
reduction of 5-HT extracellular cortical levels (F (1,7) 1.137, p <br />
0.0001, when compared with saline) (Fig. 8A).<br />
To test whether this lack of effect of 8-OHDPAT is attributable<br />
to a reduction of 5-HT 1A receptor density on serotonergic cells,<br />
we analyzed 5-HT 1A receptors expression by Western blot on a<br />
plasma membrane enriched fraction from prefrontal cortex (heteroreceptors)<br />
and DRN (autoreceptors) 100 min after a tranylcypromine<br />
injection. Figure 8B shows that the 5-HT 1A protein<br />
migrates as immunoreactive bands of 50 and 63 kDa. This<br />
finding is in agreement with that previously described in rat brain<br />
(el Mestikawy et al. 1990). As expected, the 5-HT 1A immunostaining<br />
strongly decreases in the 5-HT 1A knock-out mice tissues,<br />
confirming the specificity of 5-HT 1A antibody. Our data show<br />
that tranylcypromine specifically decreases the 5-HT 1A immunoreactive<br />
bands in DRN ( p 0.0001), but not in prefrontal cortex,<br />
whereas the total amount of membrane protein loaded, as shown<br />
with the 5-HTT staining, stays constant in all conditions (Fig.<br />
8C). This relative diminution of 5-HT 1A protein levels in the<br />
membrane enriched fraction suggests that the 5-HT 1A autoreceptors<br />
have been internalized.<br />
Discussion<br />
The main finding of our study is that nicotine needs the association<br />
with an irreversible and nonselective MAOI to induce the<br />
same neurochemical modifications as those observed with compounds<br />
belonging to the main groups of drugs of abuse (i.e.,<br />
amphetamine, cocaine, morphine, or alcohol) (Salomon et al.,<br />
2006; Lanteri et al., 2008). Moreover, although repeated injections<br />
of nicotine alone do not enhance the hyperlocomotor effects<br />
of amphetamine or PCA, tranylcypromine pretreatment al-<br />
lows nicotine to induce a robust and<br />
persistent cross-sensitization to these two<br />
drugs. Our data also show that, as with all<br />
drugs of abuse tested up to now, the neurochemical<br />
and behavioral effects of nicotine<br />
revealed by MAO inhibition are prevented<br />
by coadministration of 1badrenergic<br />
and 5-HT 2A receptor<br />
antagonists but not by a D 1 receptor antagonist.<br />
This confirms that repeated stimulation<br />
of 1b-adrenergic and 5-HT 2A receptors,<br />
but not of D 1 receptors, is a critical<br />
step in the development of long-lasting effects<br />
of drugs of abuse (Auclair et al., 2004;<br />
Salomon et al., 2006; Lanteri et al., 2008).<br />
First, we may wonder why nicotine<br />
does not induce by itself sensitization of<br />
noradrenergic and serotonergic neurons<br />
nor behavioral sensitization?<br />
The mechanism by which drugs of<br />
abuse are supposed to increase locomotor<br />
activity has been linked to their ability to<br />
stimulate mesolimbic dopaminergic<br />
transmission (Kelly et al., 1975; Kelly and<br />
Iversen, 1976). Nicotine is known to stimulate<br />
dopamine (DA) release in the nucleus<br />
accumbens via the stimulation of<br />
nicotinic receptors located in the ventral<br />
tegmental area (Di Chiara and Imperato,<br />
1988; Vezina et al., 1992; Nisell et al., 1994;<br />
Pontieri et al., 1996). Therefore, it has been proposed that MAO<br />
inhibition contributes synergistically with nicotine to enhance its<br />
reinforcing effects by maintaining an increased DA concentration<br />
in the nucleus accumbens (Lewis et al., 2007). However, we<br />
previously showed that GBR12783 [1-[2-(diphenylmethoxy)ethyl]-4-(3-phenyl-2-(propenyl)-piperazine],<br />
which specifically<br />
blocks DA uptake, does not trigger locomotor response to nicotine<br />
in C57BL/6 mice (Villégier et al., 2006b). This strongly suggests<br />
that DA release is not a limiting factor in the development of<br />
a locomotor response to nicotine. Interestingly, we found that<br />
only a compound that increases 5-HT release could elicit a locomotor<br />
response to nicotine in these mice (Villégier et al., 2006b).<br />
Functional interactions between ascending monoaminergic<br />
systems have been well characterized and are thought to play a<br />
key role in addictive processes. Indeed, noradrenergic and serotonergic<br />
neurons control behavioral response and subcortical DA<br />
release induced by psychostimulants or opiates through the stimulation<br />
of 1b-adrenergic and 5-HT 2A receptors (Blanc et al.,<br />
1994; Darracq et al., 1998; Auclair et al., 2002, 2004; Drouin et al.,<br />
2002).<br />
In rats, nicotine has been shown to increase noradrenergic<br />
neurons activity (Egan and North, 1986; Engberg, 1989) and to<br />
stimulate NE release both in vitro (Clarke and Reuben, 1996) and<br />
in vivo (Mitchell, 1993). Here, in mice, we failed to detect an<br />
increase in cortical NE levels in response to nicotine in absence or<br />
presence of tranylcypromine. Although it may be attributable to<br />
species differences, this suggests that microdialysis may, under<br />
certain experimental conditions, be not sensitive enough to detect<br />
short-lasting releases of neurotransmitters (Brazell et al.,<br />
1991).<br />
Depending on experimental conditions, nicotine can either<br />
increase or decrease serotonergic neurons firing (Mihailescu et<br />
al., 1998; Engberg et al., 2000). Indeed, activation of presynaptic
994 • J. Neurosci., January 28, 2009 • 29(4):987–997 Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons<br />
Figure 6. Effects of WAY 100635, a 5-HT 1A receptor antagonist, on locomotor activity induced by nicotine after acute or repeated treatments. A, C, Acute, Animals received an injection of WAY<br />
100635 (1 mg/kg) or saline and, 30 min later, an injection of nicotine (1 mg/kg) or saline, and locomotor activity was monitored. B, D, Pretreated, Animals received 4 consecutive days, once a day,<br />
either repeated saline plus saline, saline plus nicotine, WAY 100635 plus saline, or WAY plus nicotine. Then, 4 d later, all animals received an injection of WAY 100635 and, 30 min later, an injection<br />
ofnicotine,andlocomotoractivitywasmeasured.C,Histogramsofacutelocomotorresponsesafterdifferentconditions(whiterectangles).***p0.0001fromcorrespondingsaline,WAY100635,<br />
or nicotine controls. D, Histograms of locomotor responses to WAY 100635 plus nicotine after different repeated pretreatments. ***p 0.0001 from acute WAY 100635 plus nicotine and repeated<br />
saline plus saline, WAY 100635 plus saline, or saline plus nicotine. Each group contained at least eight animals. sal, Saline; nico, nicotine; WAY, WAY 100635. Error bars indicate SEM.<br />
nicotinic receptors in DRN depolarizes<br />
most of serotonergic cells through the release<br />
of NE and the stimulation of 1adrenergic<br />
receptors (Li et al., 1998).<br />
However, the pharmacological blockade<br />
by prazosin of this response unmasks a hyperpolarization<br />
mediated by 5-HT acting<br />
on somatodendritic 5-HT 1A autoreceptors<br />
(Li et al., 1998). Nicotine-induced activation<br />
of serotonergic neurons would be, in<br />
absence of MAOI, quickly blocked by indirect<br />
activation of an inhibitory retrocontrol,<br />
thus explaining why nicotine fails to<br />
increase locomotor activity in mice. Incidentally,<br />
it has been shown that 5-HT 1A<br />
receptor agonists can reduce locomotor<br />
hyperactivity induced by cocaine (Carey et<br />
al., 2004), confirming the critical role<br />
played by 5-HT in the behavioral output.<br />
Our data indicate that a 5-HT 1A receptor<br />
agonist reveals a locomotor response to<br />
nicotine if nicotine is injected 100 min after<br />
the agonist administration. Paradoxically,<br />
a 5-HT 1A receptor antagonist mimics<br />
this effect and, moreover, when<br />
repeatedly injected with nicotine, induces<br />
behavioral sensitization and sensitization of noradrenergic and<br />
serotonergic neurons. This indicates that a locomotor response<br />
to nicotine can occur if 5-HT 1A receptors are inactivated after<br />
either their desensitization or their blockade. Interestingly, 100<br />
min are needed to observe the effects of tranylcypromine on<br />
Figure 7. Effects of repeated WAY 100635 plus nicotine on sensitization of noradrenergic and serotonergic neurons and<br />
behavioral sensitization. Animals were repeatedly treated once a day during4dbyWAY100635 (1 mg/kg) and nicotine (1<br />
mg/kg), and WAY 100635 and saline. Four days after the last injection, D-amphetamine (2 mg/kg) or PCA (7 mg/kg) was administered<br />
and cortical extracellular NE (A) or 5-HT (C) levels, respectively, or locomotor responses (B, D, respectively) were analyzed.<br />
Data of repeated nicotine, presented in Figure 2, have been omitted for sake of clarity. Each group contained at least five animals for<br />
microdialysis experiments and eight animals for locomotor activity determination. Mean basal extracellular NE and 5-HT levels were<br />
similar to those of Figure 2. Amph, D-Amphetamine; nico, nicotine; WAY, WAY 100635. Error bars indicate SEM.<br />
nicotine-induced locomotor response (Villégier et al., 2006a,b), a<br />
delay similar to that necessary for 8-OHDPAT to induce a locomotor<br />
response to nicotine (Fig. 5B).<br />
Finally, our data show that 8-OHDPAT, at a dose shown to<br />
inhibit neuronal firing, fails to decrease 5-HT extracellular levels<br />
100 min after a tranylcypromine injection. This lack of effect of
Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons J. Neurosci., January 28, 2009 • 29(4):987–997 • 995<br />
Figure 8. Short-term effects of tranylcypromine on 5-HT 1A receptors. A, Cortical 5-HT extracellular<br />
levels were measured in mice after injection of either saline or tranylcypromine (first<br />
arrow)and,100minlater,salineor8-OHDPAT(secondarrow).Inanotherseriesofexperiments,<br />
animals received, 100 min after a tranylcypromine injection, a perfusion of TTX (1 M) (dotted<br />
lines).N5animalspergroup.B,Micewereinjectedwitheithersalineortranylcypromineand<br />
PFC or DRNs were punched 100 min later. Experiments were also performed with cerebral<br />
tissues from animals deprived of 5-HT 1A receptors (KO). Levels of 5-HTT and 5-HT 1A receptors<br />
were determined in the presence of respective antibodies using -actin as a reference. ExperimentshavebeenperformedthreetimeswithN5miceforprefrontalcortexandN8mice<br />
for raphe nuclei. C, Histograms of relative expression of 5-HT 1A receptors when compared with<br />
-actin. ***p 0.001 when compared with respective controls. a Experiments with KO mice<br />
havebeenperformedtwice.sal,Saline;tranylortran,tranylcypromine.ErrorbarsindicateSEM.<br />
8-OHDPAT is correlated to a decreased membrane expression of<br />
5-HT 1A receptor in the DRN, which is not observed in the prefrontal<br />
cortex. This latter point may be attributable to a different<br />
coupling to G-protein in the raphe nucleus or to a lower<br />
tranylcypromine-induced increase in 5-HT extracellular levels in<br />
the prefrontal cortex than in the DRN. In any case, this result is<br />
consistent with previous findings showing an internalization of<br />
5-HT 1A autoreceptors but not heteroreceptors 60 min after an<br />
acute injection of 8-OHDPAT or fluoxetine (Riad et al., 2001;<br />
2004). Together, these findings indicate that tranylcypromine is<br />
able to trigger, as soon as 100 min after its injection, a strong<br />
desensitization of 5-HT 1A autoreceptors.<br />
Following that line, it can be proposed that tranylcypromine<br />
effects on nicotine-induced locomotor activity, as well as on behavioral<br />
and neurochemical sensitizations, are attributable to the<br />
desensitization of 5-HT 1A autoreceptors. The absence of behavioral<br />
response to nicotine in absence of MAOIs may therefore be<br />
attributable to the blockade of DRN neurons electrical activity<br />
(Engberg et al., 2000; Li et al., 1998) induced by the indirect<br />
agonist effect of nicotine on 5-HT 1A receptors. MAOIs, because they<br />
enhance serotonergic tone, desensitize 5-HT 1A autoreceptors and<br />
allow the stimulating effects of nicotine on serotonergic cells.<br />
The second challenge of this study is to understand how repeated<br />
injections of nicotine and tranylcypromine trigger a neurochemical<br />
and behavioral sensitization. Whereas tobacco addiction<br />
is generally thought to be mediated by mesolimbic<br />
dopaminergic system (Balfour et al., 1998; Di Chiara, 2000), our<br />
findings indicate that the development of the sensitization of<br />
noradrenergic and serotonergic neurons by nicotine is not related<br />
to its ability to activate D 1 transmission. Similarly, we previously<br />
showed that DA transmission is not involved in the development<br />
of noradrenergic and serotonergic sensitization after<br />
psychostimulants, opiates, or alcohol (Lanteri et al., 2008). Together,<br />
these data lead us to conclude that, although there is no<br />
doubt that DA transmission is involved in the expression of behavioral<br />
sensitization induced by drugs of abuse (Nestler, 1992;<br />
Vezina, 1996; Pierce and Kalivas, 1997), DA transmission is not<br />
involved in the development of neurochemical and behavioral<br />
sensitizations, whatever the drug of abuse.<br />
Because prazosin and SR46349B prevent sensitization of noradrenergic<br />
and serotonergic neurons induced by nicotine when<br />
associated with tranylcypromine, this may indicate that, as it was<br />
shown for others drugs of abuse, the addictive properties of nicotine<br />
are linked to its ability to increase extracellular NE and<br />
5-HT levels. However, repeated injections of tranylcypromine<br />
alone, which, as shown here, release both NE and 5-HT, do not<br />
lead to sensitization of noradrenergic and serotonergic neurons<br />
nor to behavioral sensitization. It may be recalled that, similarly,<br />
repeated injections of venlafaxine or clorimipramine, two nonaddictive<br />
compounds that block both NE and 5-HT reuptake<br />
activities (Millan et al., 2001), do not increase reactivity of noradrenergic<br />
and serotonergic neurons (Lanteri et al. 2008). One<br />
hypothesis could be that development of this neurochemical sensitization<br />
needs repeated intense and phasic stimulations of 1badrenergic<br />
and 5-HT 2A receptors, whereas antidepressants induce<br />
only slow and moderate increases of noradrenergic and<br />
serotonergic transmissions (Millan et al., 2001), as well as shown<br />
here for tranylcypromine and 5-HT release. Because each antagonist<br />
could block behavioral sensitization to nicotine plus tranylcypromine,<br />
it may be assumed that activation of one system by<br />
nicotine needs the activation of the other, as shown by Li et al.<br />
(1998) with regard to the activation of 5-HT cells by NE.<br />
The question of the mechanism of sensitization of noradrenergic<br />
and serotonergic neurons remains, however, unanswered.<br />
Anatomical and functional studies between noradrenergic and<br />
serotonergic systems indicate that the firing rate of serotonergic<br />
neurons in raphe nuclei is under the excitatory control of 1badrenergic<br />
receptors (Baraban and Aghajanian, 1980; Bortolozzi<br />
and Artigas, 2003). Conversely, serotonergic neurons hyperpolarize<br />
noradrenergic cells in locus ceruleus through the tonic<br />
stimulation of 5-HT 2A receptors expressed by GABAergic interneurons<br />
(Gorea and Adrien, 1988; Szabo and Blier, 2001). In<br />
addition, both systems innervate the prefrontal cortex, an area<br />
that controls behavioral responses through glutamatergic afferents<br />
onto the ventral tegmental area (Kalivas and Duffy, 1998)<br />
and the nucleus accumbens (Pierce et al., 1996).<br />
We propose that, when 5-HT 1A receptors are desensitized or<br />
blocked, nicotine releases NE and 5-HT and stimulates 1badrenergic<br />
and 5-HT 2A receptors. Repeating nicotine consumption<br />
would repeatedly stimulate these receptors and impair the
996 • J. Neurosci., January 28, 2009 • 29(4):987–997 Lanteri et al. • MAOIs and Nicotine Sensitize NE and 5-HT Neurons<br />
mutual regulation between noradrenergic and serotonergic systems,<br />
thus leading to an increased reactivity of both groups of<br />
neurons. Increased responses of noradrenergic and serotonergic<br />
neurons to sensory stimulations may therefore represent a common<br />
mechanism underlying long-lasting effects of all drugs of<br />
abuse, including tobacco (Lanteri et al., 2008; Tassin, 2008).<br />
In humans, nicotine replacement therapies are the most<br />
widely used form of pharmacological intervention, but have<br />
proven to be remarkably unsuccessful (Silagy et al., 2004; Medioni<br />
et al., 2005). Interestingly, most tobacco smokers relapse<br />
after a few week withdrawal (i.e., when inhibition of monoamine<br />
oxidases activity by tobacco and tobacco smoke is likely to have<br />
disappeared). MAOIs, or any compound able to desensitize<br />
5-HT 1A autoreceptors, may provide a more complete scheme of<br />
the addictive properties of tobacco in experimental models of<br />
reward.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
44 Cytotoxic FlavourArt about their opinion of Liq-<br />
uids with 9 mg ml nicotine.
Characterization of chemicals released to the environment by<br />
electronic cigarettes use (ClearStream-AIR project):<br />
is passive vaping a reality? 3<br />
G. Romagna MD 1 ,L.Zabarini 1 ,L.Barbiero 1 , E. Bocchietto 1 ,S.Todeschi 1 ,<br />
E. Caravati 1 ,D.Voster 1 , K. Farsalinos MD 2<br />
September 1, 2012<br />
1 ABICH S.r.l., biological and chemical toxicology research laboratory, Verbania, Italy<br />
2 Onassis Cardiac Surgery Center, Athens, Greece<br />
3 Abstract was accepted and presented as poster at the SRNT meeting 2012 in Helsinki.<br />
Abstract<br />
Background Electronic cigarettes (e-CIG) have been marketed as a safer alternative habit to tobacco<br />
smoking. We have developed a group of research protocols to evaluate the effects of e-CIG on human<br />
health, called ClearStream. No studies have adequately evaluated the effects of e-CIG use on the release<br />
of chemicals to the environment. The purpose of this study was to identify and quantify the chemicals<br />
released on a closed environment from the use of e-CIG (ClearStream-AIR).<br />
Methods A 60 m 3 closed-room was used for the experiment. Two sessions were organized, the first using<br />
5 smokers and the second using 5 users of e-CIG. Both sessions lasted 5 h. Betweensessions,theroomwas<br />
cleaned and ventilated for 65 h. Smokersusedcigarettescontaining0.6 mg of nicotine while e-CIG users<br />
used commercially available liquid (FlavourArt) with nicotine concentration of 11 mg/ml. Wemeasured<br />
total organic carbon (TOC), toluene, xylene, carbon monoxide (CO), nitrogen oxides (NOx), nicotine,<br />
acrolein, poly-aromatic hydrocarbons (PAHs) glycerin and propylene glycol levels on the air of the room.<br />
Results During the smoking session, 19 cigarettes were smoked, administering 11.4 mg of nicotine<br />
(according to cigarette pack information). During the e-CIG session, 1.6 ml of liquid was consumed, administering<br />
17.6 mg of nicotine. During the smoking session we found: TOC=6.66 mg/m 3 ,toluene=1.7 µg/m 3 ,<br />
xylene=0.2 µg/m 3 , CO=11 mg/m 3 ,nicotine=34 µg/m 3 ,acrolein=20 µg/ml and PAH=9.4 µg/m 3 .Noglycerin,<br />
propylene glycol and NOx were detected after the smoking session. During the e-CIG session we<br />
found: TOC=0.73 mg/m 3 and glycerin=72 µg/m 3 . No toluene, xylene, CO, NOx, nicotine,acroleinor<br />
PAHs were detected on room air during the e-CIG session.<br />
Conclusions Passive vaping is expected from the use of e-CIG. However, the quality and quantity of<br />
chemicals released to the environment are by far less harmful for the human health compared to regular<br />
tobacco cigarettes. Evaporation instead of burning, absence of several harmful chemicals from the liquids<br />
and absence of sidestream smoking from the use of the e-CIG are probable reasons for the difference in<br />
results.<br />
1
Introduzione<br />
La rapida espansione, negli ultimi anni, del mercato<br />
della sigaretta elettronica, legata in parte alla possibilità<br />
di utilizzarla anche nei luoghi in cui è vietato<br />
fumare, ha fatto sorgere alcune perplessità sulla sua<br />
sicurezza in questi contesti. Ad oggi però queste<br />
perplessità si basano più su ragionamenti di tipo<br />
ipotetico che su valutazioni scientifiche. Scopo di<br />
questo esperimento, è quello di iniziare a comprendere<br />
e misurare qual è l’impatto del fumo elettronico<br />
sull’atmosfera di un ambiente chiuso, confrontandolo<br />
con il fumo tradizionale.<br />
Protocollo<br />
Per l’esperimento è stata predisposta una stanza, con<br />
un volume pari a circa 60 m 3 ,all’internodellaquale<br />
sono stati allestiti dei sistemi di campionamento<br />
dell’aria.<br />
Al fine di garantire una maggiore sensibilità e<br />
per rimuovere la variabile legata al ricircolo d’aria,<br />
l’esperimento è stato condotto in un ambiente senza<br />
rinnovo d’aria esterna.<br />
Iparametrianalizzatisonostati:<br />
• CO<br />
• NOx<br />
• Acroleina<br />
• Idrocarburi Policiclici Aromatici (IPA)<br />
• Carbonio Organico Totale (COT)<br />
• Sostanze Organiche Volatili (SOV)<br />
• Nicotina<br />
• Glicerina<br />
• Glicole Propilenico<br />
Alcuni di questi parametri (CO, NOx, COT) sono<br />
stati monitorati in continuo. Per tutti gli altri sono<br />
state impiegate delle fiale e delle membrane specifiche<br />
per catturare le varie famiglie di composti in esame<br />
in modo cumulativo.<br />
Procedura<br />
L’esperimento si è svolto in 2 sessioni, una per i fumatori<br />
ed una per i vaper 1 ,delladuratadi5 h ciascuna<br />
ed ha coinvolto, per ogni sessione, 5 volontari.<br />
1 Termine anglosassone gergale, utilizzato per indicare un<br />
utilizzatore abituale di sigaretta elettronica.<br />
2<br />
Introduction<br />
The rapid expansion of the e-cigarette market in<br />
recent years, due in part to the fact that they can<br />
be used also in no smoking areas, has given rise to<br />
perplexities on their safety in these contexts. However,<br />
thus far, these perplexities are based more on<br />
hypothetical reasons rather than scientific evaluations.<br />
The aim of this experiment is to understand<br />
and to measure what kind of impact e-cigarettes use<br />
has on a closed environment atmosphere compared<br />
to traditional cigarette smoking.<br />
Protocol<br />
A 60 m 3 volume room was used for the experiment.<br />
This room was fitted with air sampling systems.<br />
In order to guarantee a higher sensitivity and remove<br />
air recirculation-dependant variables, the experiment<br />
was performed without renewal of indoor air.<br />
The following parameters were analyzed:<br />
• CO<br />
• NOx<br />
• Acrolein<br />
• Polycyclic Aromatic Hydrocarbons (PAHs).<br />
• Total Organic Carbon (TOC)<br />
• Volatile Organic Compounds (VOCs)<br />
• Nicotine<br />
• Glycerine<br />
• Propylene Glycol<br />
Some of these parameters (CO, NOx, TOC) were<br />
monitored continuously. For all the other parameters,<br />
in order to capture the various types of compounds<br />
cumulatively, vials and specific membranes<br />
were used.<br />
Procedures<br />
The experiment was divided in two sessions: one for<br />
vapers 1 and one for smokers. Each session lasted 5 h<br />
and involved 5 volunteers.<br />
Between the sessions the room was cleaned and<br />
ventilated for 65 h, inordertorestoretheoriginal<br />
1 English slang term indicating an electronic cigarette user.
Tra le due sessioni la stanza è stata pulita ed<br />
arieggiata per complessive 65 h al fine di ripristinare<br />
le condizioni di neutralità iniziali.<br />
Sessioni di Campionamento<br />
Nel corso delle due prove, dopo aver allestito la<br />
stanza per il campionamento e rilevato i parametri di<br />
partenza, 5 volontari hanno fumato le loro sigarette<br />
ousatolaloropersonalesigarettaelettronica,a<br />
seconda della sessione in corso.<br />
Ai volontari è stato spiegato che avrebbero potuto<br />
fumare/svapare 2 nelle quantità e nei tempi più<br />
adatti alle loro personali esigenze, a condizione di<br />
svolgere questa attività sempre all’interno del locale<br />
predisposto per l’esperimento.<br />
La permanenza nel locale è stata tassativamente<br />
limitata al tempo strettamente necessario a fumare/svapare.<br />
L’accesso e la permanenza nel locale sono stati<br />
consentiti ad un massimo di 3 volontari contemporaneamente.<br />
La porta della stanza è rimasta chiusa se non per<br />
il tempo necessario ad entrare o ad uscire.<br />
Tutti i volontari hanno firmato un consenso informato<br />
prima di prendere parte allo studio.<br />
Per la sessione fumatori, si è provveduto ad annotare<br />
il numero di sigarette fumate, mentre per la<br />
sessione vaper èstatovalutatoilpesodelliquido<br />
consumato, con una bilancia di precisione.<br />
Volontari<br />
Ivolontarifumatoriavevanounetàmediadicirca21<br />
anni con una storia media di 6.5 anni di fumo ed un<br />
consumo medio giornaliero di circa 17 sigarette. Il<br />
contenuto di nicotina delle sigarette fumate era pari<br />
a 0.6 mg per sigaretta. Nel corso della sessione di<br />
campionamento sono state fumate complessivamente<br />
19 sigarette, che hanno dispensato ai fumatori circa<br />
11.4 mg di nicotina, basandosi su quanto riportato<br />
sul pacchetto.<br />
I vaper hanno dichiarato di usare la sigaretta<br />
elettronica in maniera esclusiva da circa 3 mesi (min<br />
1, max 6) con un consumo giornaliero di liquido 3<br />
pari a 1.5 ml euncontenutodinicotinamediodi<br />
11 mg/ml. Tutti i volontari, hanno usato un liquido<br />
commerciale (Heaven Juice tradizionale) prodot-<br />
2 Termine gergale largamente usato, derivato dall’inglese<br />
to vape, ed impiegato per indicare l’azione di chi fuma una<br />
sigaretta elettronica.<br />
3 Tutti i liquidi per sigaretta elettronica utilizzati nell’esperimento<br />
erano del tipo Heaven Juice Tradizionale di FlavourArt,<br />
contenenti circa il 40% di glicerolo USP, circa il 50% di<br />
glicole propilenico USP, da 0.9% a 1.8% di nicotina USP,
Nicotina<br />
Nicotine<br />
Glicoli - Glicerina<br />
Glycols - Glycerine<br />
Composti Analizzati<br />
Analyzed compounds<br />
Idrocarburi Policiclici Aromatici (IPA)<br />
Polycyclic Aromatic Hydrocarbons (PAHs)<br />
Acroleina<br />
Acrolein<br />
SOV<br />
VOCs<br />
Supporto di campionamento<br />
Sampling medium<br />
Fiala XAD-2<br />
XAD-2 vial<br />
Filtro in fibra di vetro + fiala XAD-7<br />
Glass fiber filter + XAD-7 vial<br />
Filtro in fibra di vetro + fiala XAD-2<br />
Glass fiber filter + XAD-2 vial<br />
Fiala di Silica gel + DPNH<br />
Silica gel vial + DPNH<br />
Fiala di carbone attivo<br />
Activated carbon vial<br />
Litri campionati (teorici)<br />
Sampled liters (theoretical)<br />
Metodo<br />
Method<br />
600 NIOSH 2544<br />
600 NIOSH 5523<br />
600 NIOSH 5515<br />
60 NIOSH 2018<br />
60 UNI EN 13649<br />
Tab. 1: Metodi utilizzati per il campionamento dei composti. / Methods used for substances sampling.<br />
to da FlavourArt eundispositivoEGOPulsedi<br />
Smokie’s R .<br />
Durante la sessione di campionamento, sono stati<br />
vaporizzati 1760 mg di liquido, pari a circa 1.6 ml e<br />
contenenti circa 17.6 mg di nicotina.<br />
Materiali e Metodi<br />
Per le metodiche di campionamento sono state adottate<br />
diverse procedure sia della normativa UNI che<br />
NIOSH, impiegando differenti fiale SKC specifiche<br />
per i diversi componenti da ricercare. Per alcune<br />
molecole sono state utilizzate anche delle membrane<br />
filtranti in fibra di vetro o in PTFE con porosità di<br />
0.8 µm (Tab.1).<br />
Ogni fiala è stata collegata ad un campionatore<br />
aspirante portatile, calibrato e impostato per aspirare<br />
uno specifico volume, in funzione della durata<br />
dell’esperimento e delle specifiche della metodica in<br />
uso.<br />
Aquestisistemidicampionamentocumulativo,<br />
sono stati affiancati, un rilevatore di CO, CO2, NOx,<br />
e un rilevatore di COT a ionizzazione di fiamma<br />
FID.<br />
Afineesperimento,lefialeelemembranesono<br />
state sigillate e trasportate presso i laboratori<br />
ABICH S.r.l. 4 per le analisi.<br />
Risultati<br />
Le analisi dei campioni hanno evidenziato numerose<br />
esostanzialidifferenzetrafumodisigarettaefumo<br />
elettronico, sia in termini di impatto sulla qualità<br />
dell’aria, sia anche in termini di tossicità. (Tab. 2).<br />
Per il campionamento sono state impiegate delle<br />
membrane in PTFE e siamo rimasti colpiti dal co-<br />
4 ABICH S.r.l., Verbania (VB), Italia<br />
4<br />
about 17.6 mg of nicotine.<br />
Materials and Methods<br />
Considering the sampling methodologies different<br />
procedures both from UNI and NIOSH have been<br />
used. Different SKC vials specific for the different<br />
components to search were used. For some molecules,<br />
also fiberglass or PTFE 0.8 µm porosity membrane<br />
filters were used (Tab. 1).<br />
Each vial was linked with a portable suction<br />
sampler, calibrated and set to aspirate a specific<br />
volume, depending on the duration of the experiment<br />
and on the method details.<br />
In addition to these cumulative sampling systems,<br />
a CO and CO2 and NOx detector and a FID flame<br />
ionization TOC detector were used.<br />
At the end of the experiment, the vials and the<br />
membranes were sealed and taken to the ABICH<br />
S.r.l. 4 labs for the analysis.<br />
Results<br />
The sampling analysis underlined many and fundamental<br />
differences between cigarette smoking and<br />
e-cigarette smoking, both in terms of impact on air<br />
quality and also on toxicity. (Tab. 2).<br />
PTFE membranes have been used for the sampling.<br />
We were surprised by the colour of the mem-<br />
4 ABICH S.r.l.,Verbania (VB), Italy
Nicotina / Nicotine<br />
Parametro<br />
Parameter<br />
Glicerina / Glycerine<br />
Glicolene Propilenico / Propylene Glycol<br />
Acroleina / Acrolein<br />
Volume Campionato*<br />
Sampled Volume* [L]<br />
Tempo di campionamento: 300 minuti. / Sampling time: 300 minutes.<br />
Concentrazione Media*<br />
Mean Concentration*<br />
[mg/m 3 ]<br />
Sigaretta Tradizionale Sigaretta Elettronica<br />
Traditional Cigarette Electronic Cigarette<br />
600 0.034 < 0.001**<br />
600 < 0.001** 0.072<br />
600 < 0.01** < 0.01**<br />
60 0.020 < 0.0016**<br />
* dati relativi alle condizioni operative di riferimento (20°C e 0.101 MPa) riprodotte dall'attrezzatura / values refer to ideal working<br />
conditions (20°C and 0.101 MPa) simulated by the equipment<br />
** inferiore alla soglia rilevabile dalla metodica / below the instrument sensitivity<br />
lore assunto dalle membrane alla fine delle sessioni.<br />
Questo, pur non costituendo un dato analitico di per<br />
sé, in qualche modo ci ha dato un’idea dei risultati<br />
che avremmo ottenuto (Fig. 3 e 4).<br />
Fig. 3: Membrana in PTFE al termine della sessione di<br />
fumo tradizionale. / PTFE membrane at the end of the<br />
cigarette smoking session.<br />
CO (Monossido di Carbonio) [12] Il monossido<br />
di carbonio non ha mostrato alcuna variazione con<br />
il fumo elettronico, rimanendo al di sotto dei limiti<br />
di rilevabilità dello strumento, mentre il fumo di sigaretta<br />
ha prodotto un costante incremento della sua<br />
concentrazione durante tutta la durata del campionamento,<br />
raggiungendo un picco di 11 mg/m 3 ,valore<br />
questo, al di sopra della soglia di legge (10 mg/m 3 ) 5<br />
(Fig. 5).<br />
Il monossido di carbonio è un gas tossico con una<br />
elevata affinità per l’emoglobina, compromettendo<br />
5 Decreto Legislativo 13 agosto 2010, n. 155. Attuazione<br />
della direttiva 2008/50/CE relativa alla qualità dell’aria<br />
ambiente e per un’aria più pulita in Europa.<br />
Tab. 2: Sostanze rilevate. / Detected substances.<br />
5<br />
branes at the end of the sessions. Even if this does<br />
not constitute analytic data as such, it has given us<br />
an idea of the results that we could expect (Fig. 3<br />
and 4).<br />
Fig. 4: Membrana in PTFE al termine della sessione di<br />
fumo elettronico. / PTFE membrane at the end of the<br />
e-cigarette session.<br />
CO (Carbon Monoxide) [12] The levels of carbon<br />
monoxide did not show any variation during ecigarette<br />
smoking, remaining below the detection limits<br />
of the tool. On the contrary cigarette smoking produced<br />
a steady elevation in CO throughout the sampling<br />
period. It reached a peak of 11 mg/m 3 , which<br />
is above the legal threshold (10 mg/m 3 ) 5 (Fig. 5).<br />
Carbon monoxide is a toxic gas with a high affinity<br />
for haemoglobin, compromising its ability to<br />
transport oxygen. Smokers, continue to exhale out<br />
high levels of CO several hours after smoking their<br />
5 Legislative decree 13th August 2010, n.155. Application<br />
of the directive 2008/50/CE concerning the quality air in the<br />
environment for a clearer air in Europe.
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
CO [mg/m3]<br />
0<br />
0m 7m 42m 59m 98m 133m 210m 240m 270m 300m<br />
Sigaretta Tradizionale / Traditional Cigarette Sigaretta Elettronica / Electronic Cigarette<br />
Fig. 5: Concentrazione di CO durante l’esperimento. / CO concentration during the experiment.<br />
la sua capacità di trasportare ossigeno. Un fumatore<br />
continua ad emettere elevati livelli di monossido di<br />
carbonio, anche molte ore dopo aver fumato l’ultima<br />
sigaretta [5].<br />
Nicotina Tra gli aspetti più interessanti, abbiamo<br />
osservato che la nicotina, pur presente nei liquidi<br />
utilizzati per l’esperimento, non è stata rilevata durante<br />
la sessione relativa al fumo elettronico. Per<br />
contro sono stati dosati 34 µg/m 3 di nicotina, con il<br />
fumo tradizionale. Va precisato che, stando a quanto<br />
riportato sui pacchetti, la quota di nicotina inalata<br />
dai fumatori, ammonta complessivamente a circa<br />
11.4 mg, mentreivaper hanno inalato nicotina per<br />
un totale di 17.6 mg. Tuttavialaquotadinicotina<br />
indicata sul pacchetto tiene conto solo della quota<br />
inalata, senza fornire alcuna informazione relativa<br />
aquellaeffettivamentepresentenellasigarettae<br />
liberata nell’aria durante la sua combustione.<br />
Basandosi sui risultati osservati è possibile dedurre<br />
che il fumo di sigaretta produce una contaminazione<br />
da nicotina nell’aria, almeno 35 volte superiore a<br />
quella del fumo elettronico, il che equivale a dire che<br />
servono almeno 35 vaper per produrre un livello di<br />
nicotina equivalente a quello prodotto da un singolo<br />
fumatore.<br />
Se inoltre avessimo bilanciato le prove, chiedendo<br />
ai fumatori, di consumare sigarette, in quantità<br />
tali da eguagliare il consumo di nicotina dei vaper,<br />
questi avrebbero dovuto fumare circa 29 sigarette,<br />
producendo una concentrazione di nicotina stimata<br />
in circa 52 µg/m 3 .<br />
Argomentare sulle ragioni di questi risultati è<br />
estremamente difficile, si potrebbe ipotizzare che<br />
esista per i vaper una differente cinetica di assorbimento<br />
della nicotina, o più semplicemente che le<br />
quantità in gioco siano estremamente contenute se<br />
paragonate a quelle effettivamente liberate dal fumo<br />
tradizionale. Ma al di là di queste ipotesi, tutte da<br />
verificare, il risultato in sé rimane un fatto: 5 vaper<br />
che utilizzano la sigaretta elettronica, per 5 h, inuna<br />
6<br />
last cigarette, even if the last cigarette was put out<br />
many hours before [5].<br />
Nicotine Among all, the most interesting aspects<br />
we observed was that nicotine was not detected in air<br />
during the e-smoking session, although liquids used<br />
for experiments contained it. On the other hand,<br />
34 µg/m 3 of nicotine were found during the smoking<br />
session. It should be made clear that, according to<br />
the information on packs, the amount of nicotine<br />
inhaled by smokers was about 11.4 mg, whilethe<br />
amount of nicotine inhaled by vapers was about<br />
17.6 mg. Howevertheamountofnicotinereportedon<br />
packs is the inhaled amount. This information does<br />
not give details about the real amount of nicotine<br />
inside the cigarettes and released in the air during<br />
combustion and from side stream smoke.<br />
Based on the observed results, we can conclude<br />
that cigarette smoking produces nicotine contamination<br />
in the air at least 35 times higher than esmoking.<br />
This means that we need at least 35 vapers<br />
to produce nicotine level in air similar to the level<br />
produced by a single smoker.<br />
Moreover if we had balanced the tests, asking<br />
cigarette smokers to consume the amount of cigarettes<br />
necessary to match the amount of nicotine used<br />
by vapers, the latter should have smoked about 29<br />
cigarettes, producing an expected nicotine concentration<br />
of about 52 µg/m 3 .<br />
It’s extremely difficult to discuss about the reasons<br />
for these results. We could suppose that there<br />
is a different absorption kinetics for nicotine. Or<br />
maybe the amount in play is extremely low, when<br />
compared to the nicotine amount released during<br />
traditional smoking. However beyond all these hypotheses,<br />
which have not been verified, there is one<br />
fact: 5 vapers using e-cigarettes for 5 h in a small<br />
room without renewal of indoor air do not produce<br />
detectable levels of nicotine in the air.
Parametro<br />
Parameter<br />
Metiletilchetone / Methylethylketone<br />
1-etil-3-metil benzene / 1-ethyl-3-methylbenzene<br />
Limonene / Limonene<br />
Decano / Decane<br />
Undecano / Undecane<br />
Dodecano / Dodecane<br />
Cedrene / Cedrene<br />
Longifolene / Longifolen<br />
Toluene / Toluene<br />
O,m,p – Xilene / o,m,p – Xylene<br />
1-etil-2-metil benzene / 1-ethyl-2-methylbenzene<br />
1,2,4-trimetil benzene / 1,2,4-Trimethylbenzene<br />
Mentene / Menthene<br />
BHT (Butilidrossitoluene / Butylhydroxytoluene)<br />
Terpene / Terpene (u.s.)<br />
Longiciclene / Longicyclene<br />
<br />
n.i. totali / total u.s.<br />
<br />
Tempo di campionamento: 300 minuti. / Sampling time: 300 minutes.<br />
Volume Campionato*<br />
Sampled Volume* [L]<br />
Concentrazione Media*<br />
Mean Concentration*<br />
[µg/m 3 ]<br />
Sigaretta Tradizionale Sigaretta Elettronica<br />
Traditional Cigarette Electronic Cigarette<br />
60 4.2 4.4<br />
60 0.2 3.4<br />
60 12.5 0.1<br />
60 0.4 4.2<br />
60 4.2 0.7<br />
60 3.7 0.3<br />
60 0.3 0.9<br />
60 18.3 30.3<br />
60 1.7 -<br />
60 0.2 -<br />
60 4.9 -<br />
60 0.3 -<br />
60 0.5 -<br />
60 - 0.4<br />
60 - 2.3<br />
60 - 2.2<br />
60 - 1.0<br />
60 14.7 12.6<br />
* dati relativi alle condizioni operative di riferimento (20°C e 0.101 MPa) riprodotte dall'attrezzatura / values refer to ideal working conditions<br />
(20°C and 0.101 MPa) simulated by the equipment<br />
** inferiore alla soglia rilevabile dalla metodica / below the instrument sensitivity<br />
Tab. 6: Sostanze Organiche Volatili. / Volatile Organic Compounds.<br />
stanza di piccole dimensioni e senza rinnovo d’aria,<br />
non producono livelli rilevabili di nicotina nell’aria.<br />
Glicole Propilenico Altro parametro inatteso è<br />
il glicole propilenico, che non è stato rilevato durante<br />
la prova con il fumo elettronico, pur costituendo il<br />
50% del liquido 3 .<br />
Questo curioso fenomeno è stato osservato anche<br />
in un altro studio simile [11]. Anche questo studio<br />
non ha rilevato nicotina nel vapore passivo di una<br />
stanza sperimentale (significativamente più piccola<br />
della stanza da noi utilizzata). Alcuni esperimenti<br />
suggeriscono che l’assorbimento del glicole propilenico<br />
per via inalatoria sia estremamente rapido [17]<br />
equestopotrebbespiegareperchéquestamolecola<br />
pur così abbondante non è stata rilevata.<br />
Glicerina e Acroleina Non è stata rilevata glicerina<br />
relativamente al fumo di sigaretta, mentre ne<br />
èstatarilevataunatracciaconilfumoelettronico,<br />
pari a 72 µg, valoremoltoaldisottodellasogliadi<br />
7<br />
Propylene Glycol Results on propylene glycol<br />
were also unexpected. During e-smoking tests, propylene<br />
glycol was not detected, although 50% of liquid 3<br />
consisted of propylene glycol.<br />
This curious phenomenon has also been observed<br />
in a similar study [11]. Even in that case, nicotine<br />
was not detected in an experimental room of the<br />
passive vaping (which was significantly smaller than<br />
the room we used). Some studies suggest that propylene<br />
glycol absorption via inhalation is extremely<br />
rapid [17]. This could explain why this molecule has<br />
not been detected even though it was present in<br />
significant amounts in the liquid used.<br />
Glycerine and Acrolein No glycerine was detected<br />
in air during cigarette smoking. On the other<br />
hand, 72 µg/m 3 were detected during e-smoking.<br />
This amount is much lower than the threshold safety
Naftalene / Naphthalene<br />
Parametro<br />
Parameter<br />
Acenaftilene / Acenaphthylene<br />
Acenaftene / Acenaphthene<br />
Fluorene / Fluorene<br />
Fenantrene / Phenanthrene<br />
Antracene / Anthracene<br />
Fluorantene / Fluoranthene<br />
Pirene / Pyrene<br />
Benzo(a)antracene / Benzo(a)anthracene<br />
Crisene / Chrysene<br />
<br />
<br />
Benzo(a)pirene / Benzo(a)pyrene<br />
Indeno(1,2,3-cd)pirene / Indeno(1,2,3-cd)pyrene<br />
Dibenzo(a,h)antracene / Dibenzo(a,h)anthracene<br />
Benzo(ghi)perilene / Benzo(g,h,i)perylene<br />
Tempo di campionamento: 300 minuti. / Sampling time: 300 minutes.<br />
Volume Campionato*<br />
Sampled Volume* [L]<br />
Concentrazione Media*<br />
Mean Concentration*<br />
[µg/m 3 ]<br />
Sigaretta Tradizionale Sigaretta Elettronica<br />
Traditional Cigarette Electronic Cigarette<br />
600 2.78 < 0.02**<br />
600 < 0.02** < 0.02**<br />
600 0.19 < 0.03**<br />
600 0.47 < 0.06**<br />
600 0.37 < 0.08**<br />
600 < 0.04** < 0.04**<br />
600 0.13 < 0.02**<br />
600 < 0.01** < 0.01**<br />
600 < 0.16** < 0.16**<br />
600 5.46 < 0.14**<br />
600 < 0.33** < 0.33**<br />
600 < 0.74** < 0.74**<br />
600 < 0.62** < 0.62**<br />
600 < 1.47** < 1.47**<br />
600 < 1.47** < 1.47**<br />
600 < 1.60** < 1.60**<br />
* dati relativi alle condizioni operative di riferimento (20°C e 0.101 MPa) riprodotte dall'attrezzatura / values refer to ideal working conditions<br />
(20°C and 0.101 MPa) simulated by the equipment<br />
** inferiore alla soglia rilevabile dalla metodica / below the instrument sensitivity<br />
Tab. 7: Idrocarburi Policiclici Aromatici. / Polycyclic Aromatic Hydrocarbons.<br />
azione (TWA-TLV 10 mg/m 3 )ebenaldisottodella<br />
soglia definita di rischio moderato o irrilevante [4].<br />
Tuttavia, bisogna rilevare che l’acroleina, molecola<br />
che si forma della disidratazione ad elevate<br />
temperature della glicerina, era presente e ben rilevabile<br />
nell’aria della stanza, durante la prova dei<br />
fumatori (20 µg/m 3 ).<br />
Ènotoinfattichelaglicerinavienespessoaggiunta<br />
ai tabacchi come umettante e durante la combustione<br />
si trasformi in acroleina [3]. L’assenza di<br />
processi di combustione nel fumo elettronico, è di<br />
fondamentale importanza per comprendere come mai<br />
l’acroleina non sia stata rilevata nell’aria durante la<br />
prova.<br />
L’acroleina è una sostanza notoriamente molto<br />
tossica e irritante, inoltre è attualmente sospetta per<br />
avere un ruolo nei processi di cancerogenesi [1].<br />
SOV Dall’analisi delle sostanze organiche volatili,<br />
sono state evidenziate fondamentalmente componenti<br />
aromatiche, in particolare il longifolene, tipico<br />
dell’aroma di pino, era presente in entrambe le prove.<br />
È probabile che questo composto facesse parte<br />
dei prodotti detergenti o deodoranti impiegati per<br />
pulire la stanza prima dell’esperimento. In merito<br />
8<br />
limit (TWA-TLV 10 mg/m 3 )andmuchlowerthan<br />
the threshold for moderate risk [4].<br />
However, it’s important to note that acrolein,<br />
amoleculeformedbydehydrationofglycerinedue<br />
to high temperatures, was present in the air of the<br />
room during cigarette smoking test (20 µg/m 3 ).<br />
In fact, it is well known that glycerine is often<br />
added to moisten tobacco. During combustion glycerine<br />
is transformed into acrolein [3]. The fact that<br />
no combustion is involved when using e-cigarettes<br />
probably plays a fundamental role in the absence of<br />
acrolein from indoor air during their use.<br />
As everyone knows, acrolein is a very toxic and<br />
irritating substance. Moreover it is currently suspected<br />
of having a fundamental role in the carcinogenic<br />
process [1].<br />
VOCs During the analysis of volatile organic compounds,<br />
aromatic components were detected, in particular<br />
longifolen, typical of pine aroma, in both<br />
tests. One of the detergents used to clean the room<br />
before the test could have contained this compound.<br />
Regarding cigarette smoking, xylene and toluene<br />
were detected. These are two very common toxic
al fumo di sigaretta, si rilevano comunque tracce di<br />
xilene e toluene, due composti tossici, normalmente<br />
presenti nel fumo di sigaretta. Il limonene, terpene<br />
dell’olio essenziale di limone, è stato rilevato solo<br />
durante la prova con il fumo tradizionale ed in effetti<br />
questa molecola è stata riscontrata anche da altri<br />
studi come componente del fumo di sigaretta [11]<br />
(Tab. 6).<br />
IPA Tra i composti più rilevanti, in termini di tossicità<br />
cronica del fumo di tabacco, ci sono certamente<br />
gli idrocarburi policiclici aromatici. Questi composti,<br />
prodotti durante il processo di combustione, sono<br />
noti per gli effetti cancerogeni e mutageni.<br />
La prova ha identificato 6 dei 16 IPA ricercati,<br />
durante la sessione con il fumo tradizionale, mentre<br />
non è stato rilevato nulla con il fumo elettronico<br />
(Tab. 7).<br />
COT [15] L’analisi del carbonio organico totale,<br />
non ci dà informazioni specifiche sulla tossicità. È<br />
un modo per valutare globalmente la quantità di<br />
materia organica immessa nell’aria, senza distinguere<br />
tra sostanze tossiche e non tossiche. Tuttavia questo<br />
parametro ci fornisce una visione globale del grado<br />
di contaminazione dell’aria, durante tutta la durata<br />
dell’esperimento.<br />
Nel grafico è possibile osservare l’andamento dei<br />
livelli di COT nell’aria durante le 5 h di campionamento.<br />
Dal grafico è stato sottratto il valore di fondo<br />
presente all’inizio del campionamento (1 mg/m 3 ).<br />
Due aspetti sono interessanti a mio parere. In<br />
primo luogo i livelli massimi con il fumo di sigaretta<br />
sono oltre 9 volte più alti che con il fumo elettronico,<br />
in secondo luogo, il fumo impiega appena 11 minuti,<br />
a raggiungere il valore massimo raggiunto dalla<br />
sigaretta elettronica (0.73 mg/m 3 ), nel tempo di 5 h<br />
(Fig. 8).<br />
Conclusioni<br />
L’esperimento su descritto ha evidenziato, limitatamente<br />
ai parametri osservati, che il fumo elettronico<br />
non comporta l’immissione nell’aria di un ambiente<br />
chiuso, di sostanze tossiche o cancerogene in quantità<br />
rilevabili. Ulteriori studi sono necessari, per<br />
approfondire e meglio definire tutti gli aspetti coinvolti,<br />
ma questa valutazione preliminare suggerisce<br />
che l’impatto del fumo elettronico passivo, se confrontato<br />
con quello del fumo di sigaretta, è talmente<br />
ridotto da essere appena rilevabile e non presenta le<br />
caratteristiche di tossicità e di cancerogenicità rilevate<br />
nel fumo di sigaretta. L’assenza di combustione e<br />
la mancanza di fumo secondario (sidestream smoke),<br />
noto per i suoi effetti tossici [2, 6], sono probabilmen-<br />
9<br />
compounds in cigarette smoking. Limonene which<br />
is an oil lemon terpene, was detected only during<br />
the traditional smoking test. In fact this molecule<br />
was found as a component in cigarette smoke even<br />
in other studies [11] (Tab. 6).<br />
PHAs Polycyclic aromatic hydrocarbons are, without<br />
doubt, among the most important compounds<br />
in terms of chronic toxicity caused by tobacco smoking.<br />
These substances, which are produced during<br />
the combustion process, are well known for their<br />
carcinogenic and mutagenic effects.<br />
During the traditional cigarette smoking session,<br />
6outof16PAHswereidentified. Nothingwas<br />
identified during the e-cigarette session (Tab. 7).<br />
TOC [15] The total organic carbon analysis does<br />
not give us specific information about toxicity. It is<br />
ameasureoftheoverallamountoforganicmatter<br />
released in the air. There is no distinction between<br />
toxic and non-toxic substances. However this parameter<br />
gives us a global view of the degree of contamination<br />
of air, throughout the whole experiment.<br />
The chart shows the TOC level trends in the air<br />
during the 5 hsampling.<br />
The chart does not contain the original value of<br />
air at the beginning of the sample (1 mg/m 3 ).<br />
In my opinion there are two interesting aspects<br />
which should be underlined. Firstly, the maximum<br />
levels during cigarette smoking sessions are 9 times<br />
higher than the e-smoking session. Secondly, cigarette<br />
smoking takes just 11 minutes to reach a value similar<br />
to the maximum value measured for the e-cigarette<br />
(0.73 mg/m 3 ), in 5 h(Fig.8).<br />
Conclusions<br />
The above experiment, within the limits of the observed<br />
parameters, has underlined that e-smoking<br />
does not produce detectable amounts of toxic and carcinogenic<br />
substances in the air of an enclosed space.<br />
Further studies are needed to better understand all<br />
the involved aspects. However this preliminary assessment<br />
indicates that passive vaping impact, when<br />
compared to the traditional cigarette smoking, is<br />
so low that it is just detectable, and it does not<br />
have the toxic and carcinogenic characteristics of<br />
cigarette smoking. The absence of combustion and<br />
the lack of sidestream smoking, with its known toxic<br />
effects [2, 6] are probably the main reasons for the<br />
differences observed in air pollution characteristics
7<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
0.72 @ 11m 00s<br />
COT [mg/m3]<br />
0h 0h 30m 1h 1h 30m 2h 2h 30m 3h 3h 30m 4h 4h 30m 5h<br />
Elettronica / Electronic Tradizionale / Traditional<br />
Fig. 8: Carbonio Organico Totale. / Total Organic Carbon.<br />
te alla base delle differenze osservate, in termini di<br />
inquinamento dell’aria, tra fumo di tabacco e fumo<br />
elettronico.<br />
Come considerazione finale, basandosi sui risultati<br />
ottenuti e sui dati dell’ARPA in materia di inquinamento<br />
urbano, potrebbe essere meno salutare,<br />
respirare l’aria di una grande città nell’ora di punta,<br />
piuttosto che sostare in una stanza con qualcuno che<br />
usa una sigaretta elettronica.<br />
References<br />
0.73 (max)<br />
6.66 (max)<br />
between e-cigarettes and tobacco smoking.<br />
On the base of the obtained results and on ARPA<br />
data about urban pollution, we can conclude by<br />
saying that could be more unhealty to breath air<br />
in big cities compared to staying in the same room<br />
with someone who is vaping.<br />
[1] K. Bein and G. D. Leikauf. “Acrolein - a pulmonary hazard”. In: Mol Nutr Food Res 55.9 (Sept.<br />
2011), pp. 1342–1360.<br />
[2] J. T. Bernert et al. “Increases in tobacco exposure biomarkers measured in non-smokers exposed to<br />
sidestream cigarette smoke under controlled conditions”. In: Biomarkers 14.2 (Mar. 2009), pp. 82–93.<br />
[3] E. L. Carmines and C. L. Gaworski. “Toxicological evaluation of glycerin as a cigarette ingredient”.<br />
In: Food Chem. Toxicol. 43.10 (Oct. 2005), pp. 1521–1539.<br />
[4] Direttiva 98/24/CE e il D.Lgs. 25/02. ”rischio moderato o irrilevante”; art. 72-sexies comma 2 D.Lgs.<br />
626/94.<br />
[5] D. N. Leitch et al. “Relation of expired carbon monoxide to smoking history, lapsed time, TLCO<br />
measurement and passive smoking”. In: Respir Med 99.1 (Jan. 2005), pp. 32–38.<br />
[6] F. Marchetti et al. “Sidestream tobacco smoke is a male germ cell mutagen”. In: Proc. Natl. Acad.<br />
Sci. U.S.A. 108.31 (Aug. 2011), pp. 12811–12814.<br />
[7] NIOSH 2018, Aldeidi - Acroleina / Determination of Aldehydes - Acrolein.<br />
[8] NIOSH 2544/EPA 8270, Determinazione della Nicotina / Determination of Nicotine.<br />
[9] NIOSH 5515/EPA 8270, Determinazione di Idrocarburi Policiclici Aromatici (metodo GCMS) /<br />
Determination of Polycyclic Aromatic Hydrocarbons (GC-MS method).<br />
[10] NIOSH 5523, Determinazione dei Glicoli / Determination of Glycols.<br />
10
[11] T. Schripp et al. “Does e-cigarette consumption cause passive vaping?” In: Indoor Air (June 2012).<br />
[12] UNI 14626/14211, Determinazione CO e NOx / Determination of CO and NOx.<br />
[13] UNI EN 1076:1999, Tubi di assorbimento mediante pompaggio per la determinazione di gas e vapori.<br />
Requisiti e metodi di prova / Absorbtion tubes by pumping for the determination of gas and vapors<br />
Requirements and test methods.<br />
[14] UNI EN 1232:1999, Atmosfera nell’ambiente di lavoro. Pompe per il campionamento personale di<br />
agenti chimici. Requisiti e metodi di prova / Atmosphere in the workplace. Pumps for personal<br />
sampling of chemical agents Requirements and test methods.<br />
[15] UNI EN 12619/135226, Determinazione carbonio organico totale (COT) (metodo continuo con<br />
rivelatore a ionizzazione di fiamma FID). L’utilizzo della norma UNI 12619/13526 é stato effettuato<br />
al semplice scopo di dare una valutazione sommaria dell’immissione di sostanze organiche totali in<br />
ambiente. / Determination of Total Organic Carbon (TOC) (continuous method with flame ionization<br />
detector FID). The standard UNI 12619/13526 has been used simply to give a rough estimate of the<br />
release of organic substances in the environment.<br />
[16] UNI EN 13649:2002, Determinazione della concentrazione in massa di singoli composti organici in<br />
forma gassosa. Metodo mediante carboni attivi e desorbimento con solvente. / Determination of the<br />
mass concentration of each organic compound in gaseous form. Method by means of active carbons<br />
and desorption through the solvent.<br />
[17] M. S. Werley et al. “Non-clinical safety and pharmacokinetic evaluations of propylene glycol aerosol<br />
in Sprague-Dawley rats and Beagle dogs”. In: Toxicology 287.1-3 (Sept. 2011), pp. 76–90.<br />
11
Nachschlagewerk zum Thema E-Zigaretten<br />
45 Acute impact of active and passive electronic<br />
cigarette smoking on serum cotinine and lung<br />
function.
http://www.ncbi.nlm.nih.gov/pubmed/23363041 1/2<br />
US National Library of Medicine<br />
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Inhal Toxicol. 2013 Feb;25(2):91-101. doi: 10.3109/08958378.2012.758197.<br />
Acute impact of active and passive electronic cigarette smoking on serum<br />
cotinine and lung function.<br />
Flouris AD, Chorti MS, Poulianiti KP, Jamurtas AZ, Kostikas K, Tzatzarakis MN, Wallace Hayes A, Tsatsaki<br />
AM, Koutedakis Y.<br />
FAME Laboratory, Centre for Research and Technology Thessaly , Karies, Trikala , Greece .<br />
Abstract<br />
Abstract Context: Electronic cigarettes (e-cigarettes) are becoming increasingly popular yet their<br />
effects on health remain unknown. Objective: To conduct the first comprehensive and standardized<br />
assessment of the acute impact of active and passive e-cigarette smoking on serum cotinine and<br />
lung function, as compared to active and passive tobacco cigarette smoking. Materials and<br />
methods: Fifteen smokers (≥15 cigarettes/day; seven females; eight males) and 15 never-smokers<br />
(seven females; eight males) completed this repeated-measures controlled study. Smokers<br />
underwent a control session, an active tobacco cigarette (their favorite brand) smoking session and<br />
an active e-cigarette smoking session. Never-smokers underwent a control session, a passive<br />
tobacco cigarette smoking session and a passive e-cigarette smoking session. Serum cotinine,<br />
lung function, exhaled carbon monoxide and nitric oxide were assessed. The level of significance<br />
was set at p ≤ 0.001 to adjust for multiple comparisons. Results: e-Cigarettes and tobacco<br />
cigarettes generated similar (p > 0.001) effects on serum cotinine levels after active (60.6 ± 34.3<br />
versus 61.3 ± 36.6 ng/ml) and passive (2.4 ± 0.9 versus 2.6 ± 0.6 ng/ml) smoking. Neither a brief<br />
session of active e-cigarette smoking (indicative: 3% reduction in FEV1/FVC) nor a 1 h passive ecigarette<br />
smoking (indicative: 2.3% reduction in FEV1/FVC) significantly affected the lung function<br />
(p > 0.001). In contrast, active (indicative: 7.2% reduction in FEV1/FVC; p < 0.001) but not passive<br />
(indicative: 3.4% reduction in FEV1/FVC; p = 0.005) tobacco cigarette smoking undermined lung<br />
function. Conclusion: Regarding short-term usage, the studied e-cigarettes generate smaller<br />
changes in lung function but similar nicotinergic impact to tobacco cigarettes. Future research<br />
should target the health effects of long-term e-cigarette usage, including the effects of nicotine<br />
dosage.<br />
PMID: 23363041 [PubMed - in process]<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
46 VAPOR TEST RESULTS BY KOREA ELECTRON-<br />
IC CIGARETTE ASSOCIATION.
Nachschlagewerk zum Thema E-Zigaretten<br />
47 Nicotine Molecular and physiological effects of<br />
nicotine in central nervous system .
5<br />
Schriften aus der Fakultät Humanwissenschaften<br />
der Otto-Friedrich-Universität Bamberg<br />
Nikotin: Molekulare und physiologische<br />
Effekte im Zentralnervensystem<br />
Ein stereospezifisches Modell zur Analyse der Nikotinperzeption,<br />
liking und sensorisch induziertem Craving<br />
Andrea Goßler<br />
UNIVERSITY OF<br />
BAMBERG<br />
PRESS
Schriften aus der Fakultät Humanwissenschaften<br />
der Otto-Friedrich-Universität Bamberg 5
Schriften aus der Fakultät Humanwissenschaften<br />
der Otto-Friedrich-Universität Bamberg<br />
Band 5<br />
University of Bamberg Press 2010
Nikotin: Molekulare und<br />
physiologische Effekte im<br />
Zentralnervensystem<br />
Ein stereospezifisches Modell zur Analyse der<br />
Nikotinperzeption, liking und sensorisch induziertem<br />
Craving<br />
von Andrea Goßler<br />
University of Bamberg Press 2010
Bibliographische Information der Deutschen Nationalbibliothek<br />
Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der<br />
Deutschen Nationalbibliographie; detaillierte bibliographische<br />
Informationen sind im Internet über http://dnb.ddb.de/ abrufbar<br />
Diese Arbeit hat der Fakultät Humanwissenschaften der Otto-Friedrich-<br />
Universität Bamberg als Dissertation vorgelegen<br />
1. Gutachter: PD Dr. Norbert Thürauf<br />
2. Gutachter: Prof. Dr. Hans Reinecker<br />
Tag der mündlichen Prüfung: 20. Januar 2010<br />
Dieses Werk ist als freie Onlineversion über den Hochschulschriften-<br />
Server (OPUS; http://www.opus-bayern.de/uni-bamberg/) der<br />
Universitätsbibliothek Bamberg erreichbar. Kopien und Ausdrucke<br />
dürfen nur zum privaten und sonstigen eigenen Gebrauch angefertigt<br />
werden.<br />
Herstellung und Druck: docupoint, Magdeburg<br />
Umschlaggestaltung: Dezernat Kommunikation und Alumni<br />
© University of Bamberg Press Bamberg 2010<br />
http://www.uni-bamberg.de/ubp/<br />
ISSN: 1866-8674<br />
ISBN: 978-3-923507-69-6 (Druckausgabe)<br />
eISBN: 978-3-923507-70-2 (Online-Ausgabe)<br />
URN: urn:nbn:de:bvb:473-opus-2385<br />
4
Für meine Eltern, meinen Bruder, meine Freunde und alle, die mich<br />
bei der Arbeit unterstützt haben
Diese Untersuchung wurde von der DFG (Deutsche Forschungsgemeinschaft)<br />
durch das Förderprogramm TH500/3-1 unterstützt.<br />
Mein besonderer Dank gilt auch Frau Sandra Löhe (Sandra Löhe Fotodesign)<br />
für die Erstellung des Titelbildes.
Inhaltsverzeichnis<br />
Inhaltsverzeichnis<br />
1. Einleitung und Überblick......................................................................... 11<br />
2. Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen ......... 17<br />
2.1. Sucht – Was ist das?........................................................................ 17<br />
2.1.1. Subtypisierungen.................................................................. 18<br />
2.1.2. Epidemiologische Aspekte................................................... 19<br />
2.2. Kriterien der Nikotinabhängigkeit................................................... 20<br />
2.2.1. Diagnostisches und statistisches Manual psychischer Störungen<br />
(DSM-IV)................................................................. 20<br />
2.2.2. Internationale statistische Klassifikation der Krankheiten<br />
und verwandter Gesundheitsprobleme (ICD-10) ................. 25<br />
2.2.3. Vergleich DSM-IV und ICD-10........................................... 28<br />
2.3. Geschichte des Rauchens ................................................................ 29<br />
2.4. Inhaltsstoffe des Tabaks .................................................................. 31<br />
2.5. Nikotinenantiomere und ihre Eigenschaften ................................... 33<br />
2.5.1. Nikotinenantiomere.............................................................. 33<br />
2.5.2. Eigenschaften des Nikotins .................................................. 34<br />
3. Neurobiologie der Nikotinabhängigkeit................................................... 37<br />
3.1. Acetylcholinrezeptoren ................................................................... 38<br />
3.2. Weitere beteiligte Neurotransmittersysteme ................................... 45<br />
3.2.1. Serotonin .............................................................................. 45<br />
3.2.2. Weitere Neurotransmitter..................................................... 46<br />
3.3. Dopaminerges Belohnungssystem................................................... 47<br />
3.3.1. Neuroanatomie des dopaminergen Belohnungssystems ...... 48<br />
3.3.2. Kortikale Projektionsbahnen................................................ 51<br />
3.3.3. Amygdala............................................................................. 51<br />
3.3.4. Dopaminerges System: Wanting oder liking?...................... 52<br />
3.3.5. Nucleus accumbens und ventrales Tegmentum ................... 53<br />
3.4. Konditionierungsmechanismen und Störungen der Verhaltenssteuerung................................................................................................<br />
56<br />
3.4.1. Konditionierungsmechanismen............................................ 56<br />
3.4.2. Störungen der Verhaltenssteuerung ..................................... 57<br />
7
8<br />
Inhaltsverzeichnis<br />
3.5. Mechanismus der Long Term Potentiation ......................................59<br />
3.6. Psychopharmakologische Wirkungen des Nikotins.........................61<br />
3.6.1. Aktivierung oder Sedierung?................................................61<br />
3.6.2. Leistungsfähigkeit ................................................................62<br />
3.6.3. Andere psychophysiologische Wirkungen des Nikotins ......63<br />
3.7. Nebenwirkungen des Nikotins.........................................................63<br />
3.8. Olfaktorisches und trigeminales System..........................................66<br />
3.9. Vergleich der Nikotinabhängigkeit mit und Abgrenzung zu anderen<br />
Süchten ......................................................................................69<br />
3.10. Zusammenhang des Nikotinkonsums mit verschiedenen psychiatrischen<br />
Krankheitsbildern...................................................................71<br />
4. Therapie der Nikotinabhängigkeit............................................................75<br />
4.1. Erfolgsprädiktoren in der Raucherentwöhnung ...............................75<br />
4.2. Psychotherapeutische Ansätze .........................................................76<br />
4.3. Pharmakologische Ansätze ..............................................................79<br />
4.3.1. Ältere Ansätze ......................................................................79<br />
4.3.2. Bupropion.............................................................................80<br />
4.3.3. Nikotinsubstitution ...............................................................80<br />
4.3.4. Vareniclin .............................................................................83<br />
4.3.5. Rimonabant...........................................................................84<br />
4.3.6. Pharmakologische Entwicklungsansätze ..............................85<br />
4.3.7. Andere Behandlungsansätze.................................................86<br />
4.4. Zusammenfassende Bewertung bisheriger Therapieverfahren ........87<br />
5. Voruntersuchungen im Bereich der Nikotinabhängigkeit ........................89<br />
5.1. EEG-Untersuchungen ......................................................................89<br />
5.1.1. Kurzdarstellung des Verfahrens ...........................................89<br />
5.1.2. relevante Voruntersuchungen mit EEG ................................91<br />
5.2. PET-Untersuchungen.......................................................................92<br />
5.2.1. Kurzdarstellung des Verfahrens ...........................................92<br />
5.2.2. relevante Voruntersuchungen ...............................................93<br />
5.3. fMRT-Untersuchungen ....................................................................94<br />
5.3.1. Kurzdarstellung des Verfahrens ...........................................94<br />
5.3.2. relevante Voruntersuchungen ...............................................95
Inhaltsverzeichnis<br />
5.4. Zusammenfassende Bewertung ....................................................... 97<br />
6. Die Untersuchung .................................................................................... 99<br />
6.1. Überblick über den Untersuchungsablauf ..................................... 100<br />
6.2. Untersuchungsinstrumente ............................................................ 102<br />
6.2.1. Olfaktometer ...................................................................... 102<br />
6.2.2. Elektroenzephalogramm .................................................... 105<br />
6.2.3. funktionelle Magnetresonanztomographie ......................... 106<br />
6.3. Eingesetzte Substanzen ................................................................. 107<br />
6.3.1. Nikotinenantiomere............................................................ 107<br />
6.3.2. Kontrollsubstanzen CO2 und Phenylethylalkohol .............. 107<br />
6.4. Daten und Datenquellen ................................................................ 108<br />
6.5. Hypothesen.................................................................................... 110<br />
6.6. Eingangsuntersuchung................................................................... 111<br />
6.7. EEG-Untersuchung ....................................................................... 114<br />
6.7.1. Stichprobe der EEG-Untersuchung.................................... 114<br />
6.7.2. Darstellung des Untersuchungsablaufs der EEG-<br />
Untersuchung ..................................................................... 114<br />
6.7.3. Auswertung der EEG-Daten .............................................. 118<br />
6.7.4. Ergebnisse der Auswertung der EEG-Daten ...................... 120<br />
6.7.5. Ergebnisse der Auswertung der psychophysischen Daten . 138<br />
6.7.6. Zusammenhänge zwischen EEG-Daten und den psychophysischen<br />
Ratings............................................................. 141<br />
6.7.7. Zusammenfassung der Ergebnisse aus der EEG-<br />
Untersuchung ..................................................................... 145<br />
6.8. fMRT-Untersuchung ..................................................................... 148<br />
6.8.1. Stichprobe der fMRT-Untersuchung.................................. 148<br />
6.8.2. Darstellung des Untersuchungsablaufs der fMRT-<br />
Untersuchung ..................................................................... 148<br />
6.8.3. Auswertung der funktionellen Bilddaten ........................... 152<br />
6.8.4. Ergebnisse der Auswertung der fMRT-Daten.................... 156<br />
6.8.5. Ergebnisse der Auswertung der psychophysischen Daten . 169<br />
6.8.6. Zusammenfassung der Ergebnisse aus der fMRT-<br />
Untersuchung ..................................................................... 171<br />
9
10<br />
Inhaltsverzeichnis<br />
7. Integration und Diskussion der Daten ....................................................175<br />
7.1. Stimulation mit unterschiedlichen Reizklassen...........................175<br />
7.2. EEG-Untersuchung........................................................................176<br />
7.3. fMRT-Untersuchung......................................................................180<br />
7.4. Integration der Untersuchungsergebnisse ......................................188<br />
8. Ausblick .................................................................................................189<br />
Literaturverzeichnis .....................................................................................193<br />
Verzeichnis der Abbildungen.......................................................................239<br />
Verzeichnis der Tabellen .............................................................................241<br />
Anhang.........................................................................................................243
Einleitung<br />
1. Einleitung und Überblick<br />
Da das öffentliche Tabakrauchen auf den Straßen und Promenaden ebenso un-<br />
anständig als gefährlich und dem Charakter gebildeter, ordnungsvoller Städte<br />
entgegen ist, so wird dasselbe nicht nur für Berlin, sondern auch für Charlot-<br />
tenburg und den Thiergarten hierdurch aufs Strengste untersagt, und darf an<br />
letztgenannten beiden Orten nur vor den Thüren der Häuser … von dort sitzen-<br />
den und stehenden statt finden. Wer sich hiergegen eine Übertretung erlaubt,<br />
wird angehalten, ihm die Pfeife abgenommen und er mit fünf Reichsthalern<br />
Geld oder verhältnismäßigem Gefängnis oder Leibstrafe bestraft werden. Wie-<br />
derholungsfälle ziehen erhöhte Strafen und Widersetzlichkeiten augenblickli-<br />
che Arretierung nach sich. Da das gegenwärtige, für die hiesige Residenz<br />
schon öfter ergangene Verbot häufig vernachlässigt worden, so wird jetzt mit<br />
aller Strenge darauf gehalten werden, und das hochlöbliche Gouvernement ist<br />
deshalb um militärische Unterstützung ersucht worden. (Conte, 1986, S. 251)<br />
So lautete die Proklamation des Berliner Polizeipräsidenten vom 8.6.1810.<br />
Während im 19.Jahrhundert vor allem die gefährlichen Seiten des Rauchens<br />
im Raum standen, entwickelte sich im 20.Jahrhundert das Image, Rauchen<br />
sei ein Symbol für schlanke und schöne Frauen bzw. männliche, erfolgreiche<br />
Männer. Dieses zunehmend durch die Massenmedien transportierte Bild<br />
führte im Laufe der Jahrzehnte zu einem immer weiter steigenden Konsum.<br />
Schließlich wurden Alkohol, das Rauchen, Medikamente und andere Arten<br />
von Drogen auch immer häufiger als Mittel zur Problemlösung und zum<br />
Umgang mit Gefühlen eingesetzt, was in der Folgegeneration jeweils über<br />
Lernen am Modell häufig zu einem sorgloseren und ähnlichen Einsatz dieser<br />
Mittel in Krisensituationen und zunehmend auch in Alltagssituationen<br />
geführt hat (Stevens-Smith, 1994).<br />
Die Nikotinabhängigkeit ist nicht nur deswegen von großer Bedeutung für<br />
die aktuelle Gesellschaft, weil sie die Nummer eins unter den vermeidbaren<br />
Todesursachen unserer Zeit ist (World Health Organization, 2006). Viele<br />
Mechanismen, die ihr zugrunde liegen, werden in neuerer Zeit auch mit der<br />
Pathophysiologie verschiedener psychiatrischer Störungsbilder wie z.B.<br />
Morbus Alzheimer oder ADHS in Verbindung gebracht. Nikotinerg-<br />
11
12<br />
Einleitung<br />
cholinerge Schaltkreise stellen sich außerdem zunehmend als entscheidender<br />
Faktor für kognitive Prozesse wie Gedächtnis, Lernen, Aufmerksamkeit<br />
und Wahrnehmung heraus.<br />
Bereits Hebb war der Meinung, dass gute Psychologie nicht ohne Physiologie<br />
bzw. Neurophysiologie betrieben werden kann:<br />
I do not suggest any subordination of psychology to physiology, but only that<br />
psychology must be influenced by physiological evidence, as neurophysiology<br />
is influenced by psychological evidence. It is clear that the psychologist´s first<br />
concern is the behavior of the normal, intact animal, and theory must not do<br />
violence to the facts of behavior (though it may be very difficult sometimes to<br />
show that violence has been done – that is, to refute a theory decisively by be-<br />
havioral evidence). But though behavioural evidence is not inferior to anatomi-<br />
cal and physiological evidence, neither is it superior. (Hebb, 1982, S. 3)<br />
Folgt man Hebb, sollte man sich die Möglichkeiten der bildgebenden Verfahren<br />
als Psychologe ebenfalls zunutze machen und zur Weiterentwicklung<br />
und Korrektur bereits bestehender Theorien durch neue Erkenntnisse verwenden,<br />
statt das Gebiet der nicht-invasiven Techniken ausschließlich dem<br />
Bereich der Medizin zu überlassen. Nur durch eine fruchtbare Zusammenarbeit<br />
zwischen beiden Feldern können qualitativ hochwertigere Theorien<br />
über menschliches Denken und Verhalten und damit auch über Störungen,<br />
sowie effektivere Behandlungsmöglichkeiten entwickelt werden. Mit Hilfe<br />
bildgebender Verfahren ist in den letzten beiden Jahrzehnten ein deutlich<br />
besseres Verständnis der neurobiologischen Basis psychiatrischer Störungen,<br />
des Substanzmissbrauchs oder normaler kognitiver Funktionen möglich<br />
geworden (z.B. Delgado, Nearing, Ledoux & Phelps, 2008; Dolan,<br />
2008; Reske & Paulus, 2008; Stein, Ives-Deliperi & Thomas, 2008). Das<br />
Ziel des Einsatzes dieser neuen Instrumente liegt also darin, durch neuartige<br />
und ergänzende diagnostische Vorgehensweisen Fortschritte in einem biopsycho-sozialen<br />
Krankheitsverständnis und dem zugehörigen Behandlungsmodell<br />
auf der Basis neuer Befunde zu erzielen.
Einleitung<br />
Im Rahmen des DFG-Schwerpunktprogramms Molekulare und physiologische<br />
Effekte im Zentralnervensystem ist das Ziel, bildgebende Verfahren<br />
einzusetzen, um sowohl das medizinische als auch das psychologische Wissen<br />
über die Nikotinabhängigkeit zu verbessern. Die erhaltenen und über<br />
die verschiedenen Untersuchungsmethoden integrierten Ergebnisse sollen<br />
dabei helfen, die zur Zeit noch wenig effektiven pharmakologischen und<br />
psychotherapeutischen Behandlungsansätze zu überdenken und effektivere<br />
Strategien für die Raucherentwöhnung zu entwickeln. Zum einen wird die<br />
Ableitung evozierter Potentiale mit Hilfe von Elektroenzephalogrammen in<br />
Folge intranasaler Reize eingesetzt. Im Einzelnen sollen elektroenzephalographische<br />
Parameter in Reaktion auf unterschiedliche Reize erhoben<br />
werden, die Auskunft über physikalische und kognitive Aspekte der Verarbeitung<br />
geben. Zusätzlich sollen psychophysiologische Maße wie Annehmlichkeit<br />
oder Verlangen zu Rauchen Auskunft über Unterschiede in der<br />
Wahrnehmung der Teilnehmer mit unterschiedlichem Rauchstatus Auskunft<br />
geben. Zum anderen sollen funktionelle Magnetresonanztomographien<br />
eingesetzt werden, bei denen ebenfalls evozierte Potentiale mit Hilfe intranasaler<br />
Reize hervorgerufen werden. Dabei sollen die Ergebnisse der Elektroenzephalographien<br />
bezüglich beteiligter Hirnregionen spezifiziert<br />
werden. Auch hier werden psychophysiologische Maße erhoben, um Zusammenhänge<br />
mit ausgelösten Aktivierungen identifizieren zu können.<br />
Neben der Untersuchung von Differenzen zwischen Teilnehmern mit variierendem<br />
Rauchstatus sollen auch stereospezifische Unterschiede zweier<br />
Nikotinenantiomere innerhalb der einzelnen Untersuchungsgruppen Betrachtungsgegenstand<br />
sein. Dabei soll das Augenmerk vor allem auf Konditionierungsmechanismen<br />
bei Rauchern gelegt werden, die nur bei der natürlich<br />
vorkommenden Nikotinsorte in Erscheinung treten sollten.<br />
Im Folgenden soll ein Überblick über die einzelnen Kapitel gegeben werden:<br />
Zu Beginn wird sich diese Arbeit mit der Geschichte und den Grundlagen<br />
der Nikotinabhängigkeit befassen. In diesem Zusammenhang soll zunächst<br />
auf die grundlegende Definition von Sucht eingegangen werden,<br />
bevor die Kennzeichen der Nikotinabhängigkeit dargestellt werden. Im<br />
13
14<br />
Einleitung<br />
Anschluss daran werden die Geschichte des Rauchens, die Inhaltsstoffe des<br />
Tabaks und die Eigenschaften der beiden Nikotinenantiomere behandelt.<br />
In den beiden folgenden Kapiteln werden die neurobiologischen Grundlagen<br />
und die bisher eingesetzten therapeutischen Verfahren bei Nikotinabhängigkeit<br />
vorgestellt. Dabei wird besonders auf die beteiligten Rezeptorsysteme<br />
und das dopaminerge Belohnungssystem eingegangen. Da sie für<br />
diese Untersuchung von entscheidender Bedeutung sind, werden zudem das<br />
olfaktorische und das trigeminale Wahrnehmungssystem näher beschrieben.<br />
Außerdem finden der Zusammenhang mit psychiatrischen Störungsbildern<br />
und die Abgrenzung von anderen Süchten Beachtung. Im therapeutischen<br />
Bereich werden neben den bekannten psychotherapeutischen Methoden<br />
auch pharmakologische Behandlungsmöglichkeiten und Entwicklungsansätze<br />
vorgestellt.<br />
Im fünften Kapitel wird ein Überblick über bereits erfolgte Untersuchungen<br />
mit bildgebenden Verfahren gegeben. Dabei werden neben Studien mit<br />
Elektroenzephalogrammen (EEG) und funktionellen Magnetresonanztomographien<br />
(fMRT) auch Positronen-Emissions-Tomographien (PET) miteinbezogen.<br />
Im ersten empirischen Teil der Arbeit wird zunächst der Trainingsablauf<br />
vorgestellt, der neben der Einganguntersuchung auch die Besonderheiten<br />
der jeweiligen Untersuchungsbausteine reflektiert. Der Gruppe der Raucher,<br />
die im weiteren Verlauf auch im Entzug untersucht werden, wird eine<br />
Gruppe Nichtraucher gegenüber gestellt, um erlernte oder biologische Veränderungen<br />
durch den Zigarettenkonsum identifizieren zu können. Neben<br />
einer kurzen Darstellung der Einschlusskriterien und der verwendeten Daten<br />
und Datenquellen wird außerdem auf die Zusammensetzung der Stichprobe<br />
eingegangen. Zudem werden die eingesetzten Substanzen und Untersuchungsinstrumente<br />
vorgestellt.<br />
Im zweiten empirischen Teil beschäftigt sich diese Arbeit mit der Darstellung<br />
der Ergebnisse aus beiden Untersuchungsbausteinen. Im ersten Schritt<br />
werden diese erst getrennt ausgewertet, bevor in einem weiteren Schritt die
Einleitung<br />
Integration der Resultate beider bildgebender Verfahren erfolgt. Dazu werden<br />
unterschiedliche Daten herangezogen, die zum einen subjektiver, zum<br />
anderen objektiver Natur sind. Als Grundlage dienen die evozierten Potentiale<br />
der EEG- und fMRT-Untersuchungen, sowie die Ratings hinsichtlich<br />
verschiedener Variablen, die während der beiden Bausteine kontinuierlich<br />
erfolgten.<br />
Schließlich werden die Ergebnisse diskutiert, es wird auf Probleme eingegangen,<br />
die während der Studie auftraten, und es werden Verbesserungsvorschläge<br />
gemacht, die bei zukünftiger Forschung in diesem Bereich berücksichtigt<br />
werden sollten. Es wird sich zeigen, inwieweit die Integration von<br />
Resultaten mit Hilfe unterschiedlicher Untersuchungsverfahren in dieser<br />
Studie einen Wissensfortschritt gegenüber der Forschung mit Einzelmethoden<br />
erzielen kann. In einem Ausblick wird auf Chancen und Möglichkeiten<br />
eingegangen, die für bildgebende Verfahren bei psychiatrischen Störungen<br />
bestehen und erläutert, warum es sich lohnen könnte, in diesem Bereich<br />
weitere Forschung zu betreiben.<br />
Ich bitte um Verständnis dafür, dass ich mich aus Gründen der Übersichtlichkeit<br />
und Lesbarkeit bei personenbezogenen Äußerungen auf die männliche<br />
Form beschränken werde, obwohl in den Versuchsgruppen natürlich<br />
beide Geschlechter vertreten waren.<br />
15
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2. Nikotinabhängigkeit – Geschichte, Hintergründe<br />
und Grundlagen<br />
Die Nikotinabhängigkeit ist möglicherweise eine der komplexesten Störungsbilder<br />
unserer Zeit. Sie gehört einerseits in den Bereich der Abhängigkeiten,<br />
die man früher auch als Süchte bezeichnet hat. Andererseits hebt sie<br />
sich in ihrem Erscheinungsbild jedoch deutlich von dem anderer Substanzabhängigkeiten<br />
ab. Dieses Kapitel beschäftigt sich deswegen zunächst mit<br />
den allgemeinen und spezifischen Grundlagen, sowie der Geschichte des<br />
Nikotinkonsums und seinen pathologischen Formen.<br />
2.1. Sucht – Was ist das?<br />
Will man Sucht definieren, so stellt man fest, dass dieses Wort etymologisch<br />
von „siech“ abgeleitet ist und eine „zwanghafte, einem nicht bezwingbaren<br />
Drang nachgebende, unkontrollierte Verhaltensweise, die den<br />
Charakter einer Störung aufweist“ (Heinz & Batra, 2003, S. 8), bezeichnet.<br />
In den letzten Jahrzehnten konnte ein zunehmend inflationärer Gebrauch<br />
dieses Begriffs beobachtet werden. So gibt es in der Alltagssprache neben<br />
den klassischen Süchten wie Alkoholsucht, Morphinsucht und Nikotinsucht<br />
zunehmend auch so genannte Verhaltenssüchte wie Spielsucht, Arbeitssucht,<br />
Esssucht und Kaufsucht bis hin zu Internet- und Sportsucht. Diese<br />
neuen Süchte werden dabei in immer neuen Varianten nach der jeweiligen<br />
Handlung benannt und können auf jeden nur denkbaren Bereich angewandt<br />
werden. Da es in der wissenschaftlichen Sprache deswegen zu einer zunehmend<br />
unschärferen Verwendung des Begriffs „Sucht“ kam, existierte er im<br />
offiziellen Sprachgebrauch der Weltgesundheitsorganisation WHO auch nur<br />
zwischen 1957 und 1963 und wurde danach durch die beiden Bezeichnungen<br />
„Missbrauch“ bzw. „Abhängigkeit“ ersetzt. Die Definition dieser beiden<br />
Begriffe erfolgt in Kapitel 2.2. im Rahmen der Darstellung der Kennzeichen<br />
und Kriterien der Nikotinabhängigkeit.<br />
17
18<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2.1.1. Subtypisierungen<br />
Auch im Rahmen der in dieser Arbeit behandelten Abhängigkeit von Nikotin<br />
gab und gibt es verschiedene Unklarheiten in der Sprachwahl. Je nach<br />
Autor existieren verschiedene Arten von Rauchern, die sich entweder hinsichtlich<br />
des Abhängigkeitsgrads oder hinsichtlich der Funktionalität des<br />
Konsums unterscheiden. Eine einheitlich anerkannte Subtypisierung konnte<br />
bisher nicht erarbeitet werden. Dennoch sollen im Folgenden einige Ansätze<br />
dargestellt werden.<br />
Analog zu Jellinek (1960), der eine Typologie für Alkoholabhängigkeit<br />
aufstellte, entwickelten Tölle und Buchkremer (1989) eine Subtypisierung<br />
von Rauchern aufgrund ihres Konsummusters. Dabei unterscheiden sie<br />
„peak seeker“, die auf die Verstärkerwirkung des Rauchens abzielen und<br />
„through maintainer“, deren Bestreben darin liegt, dem Auftreten von Entzugssymptomen<br />
oder anderen aversiv erlebten Befindlichkeiten entgegen zu<br />
wirken. Andere Typologisierungen verwerten eher die Intensität des Konsums<br />
und der Entzugszeichen für eine Klassifikation mit den Kategorien<br />
„abhängiger“, „kontrollierter“, „neurotischer“ oder „Gelegenheitskonsum“.<br />
Anders als bei Alkohol, bei dem für die Diagnose die Folgen des Konsums<br />
als Kriterium unabdingbar sind, wird bei der Nikotinabhängigkeit in den<br />
meisten Fällen die Stärke des Konsums und des Cravings bei Verzicht als<br />
dimensionale Größe herangezogen, um eine Quantifizierung zu erreichen.<br />
So bildet z.B. der Fagerström-Test für Nikotinabhängigkeit die Wahrscheinlichkeit<br />
für das Auftreten von Entzugserscheinungen und beim männlichen<br />
Geschlecht auch die Rückfallgefahr bei einem Abstinenzversuch zuverlässig<br />
ab (Fagerstrom, Heatherton & Kozlowski, 1990; Schupp, Batra &<br />
Buchkremer, 1997). Er bestand ursprünglich aus acht dichotomen Fragen.<br />
Dem Betroffenen wurde hier ab einem Wert von mehr als sieben Punkten<br />
eine starke Abhängigkeit zugewiesen. In den 90er Jahren wurde der Test auf<br />
sechs Fragen gekürzt (aktuelle Version siehe Anhang).<br />
In einer Rauchertypisierung von Harten (1994) wird dagegen zwischen drei<br />
Gruppen unterschieden, die hinsichtlich der Motivstruktur variieren. Dazu<br />
zählen neben 20-30% Gelegenheits- oder Genussrauchern, die das Rauchen
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
als Genussmittel oder hin und wieder zur Problemlösung nutzen, 50-60%<br />
abhängige oder gewohnheitsmäßige Raucher, die er wie folgt beschreibt:<br />
„Diese Raucher bleiben- oft bis an ihr Lebensende bei der Menge Zigaretten,<br />
auf die sie sich im Laufe der Zeit eingespielt haben. Dieser Typ vermag<br />
durch Einsicht jederzeit in einer bestimmten Situation oder für eine überschaubare<br />
Phase das Rauchen vorübergehend aufzugeben. Erst, wenn es um<br />
eine endgültige Entscheidung geht, zeigt sich die tatsächliche Abhängigkeit“<br />
(S. 84). Als letzte Gruppe nennt er 20% Suchtraucher, deren Rauchverhalten<br />
durch Dosissteigerung, Kontrollverlust, Entzugserscheinungen<br />
und soziale Schädlichkeit gekennzeichnet ist.<br />
2.1.2. Epidemiologische Aspekte<br />
Laut dem National Center for Health Statistics (1990) starben allein in den<br />
USA im Jahr 1990 circa 400 000 Menschen an Krankheiten, die mit dem<br />
Rauchen in Verbindung gebracht werden. Dies würde täglich mehr als 1000<br />
Toten entsprechen. Für den Zeitraum von 1964 und 1994 betrifft das ungefähr<br />
6 Millionen Menschen. Im Vergleich dazu erliegen nur circa 15 bis 25<br />
Betroffene pro Tag den Folgen der Einnahme von Kokain, Heroin und PCP<br />
bzw. 350 bis 400 dem Alkoholkonsum. Rauchen ist damit laut der World<br />
Health Organization (1999) nach Malaria die zweithäufigste Todesursache<br />
der Welt. Die meisten Raucher beginnen bereits in der Adoleszenz. Die<br />
Hälfte von denen, die im Erwachsenenalter noch weiter rauchen, wird an<br />
den Folgen des Rauchens sterben. In den Entwicklungsländern nimmt die<br />
Anzahl der Raucher trotz der gewonnenen Erkenntnisse kontinuierlich zu<br />
(Peto, Lopez, Boreham, Thun & Heath, 1994), so dass für das Jahr 2030 das<br />
Rauchen als die häufigste einzelne Todesursache mit weltweit mehr als acht<br />
Millionen Todesfällen pro Jahr vorhergesagt wird. Jeder zehnte Todesfall<br />
wird darauf zurückzuführen sein (World Health Organization, 2006). Aktuell<br />
rauchen laut dem Statistischen Jahrbuch des Statistischen Bundesamts<br />
(2007)(2007) 28,7% der Gesamtbevölkerung in Deutschland, 24,5% sind<br />
regelmäßige Raucher.<br />
19
20<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2.2. Kriterien der Nikotinabhängigkeit<br />
Im Bereich psychischer, psychosomatischer bzw. psychiatrischer Krankheitsbilder<br />
haben sich im 20. Jahrhundert zwei Diagnosesysteme als allgemein<br />
verbindlich etabliert. Dabei handelt es sich um die Internationale<br />
Klassifikation psychischer Störungen, auch ICD-10 genannt (Weltgesundheitsorganisation,<br />
2006) und das von der American Psychiatric Association<br />
entwickelte Diagnostische und statistische Manual psychischer Störungen,<br />
auch als DSM-IV (American Psychiatric Association, 1998) oder in ihrer<br />
aktuellsten Version als DSM-IV-TR (American Psychiatric Association,<br />
2003) bezeichnet. Sie sind sowohl in der Forschung als auch in der klinischen<br />
Praxis die Grundlage jeder Diagnosestellung. Entsprechend sollen in<br />
dem vorliegenden Kapitel die Kriterien der Nikotinabhängigkeit aus Sicht<br />
beider Systeme dargestellt und auf Unterschiede kurz eingegangen werden.<br />
2.2.1. Diagnostisches und statistisches Manual psychischer Störungen<br />
(DSM-IV)<br />
Die Nikotinabhängigkeit wurde erstmals im DSM-III als eigenes Störungsbild<br />
mit aufgenommen (Karan & Rosecrans, 2000). Im DSM-IV (American<br />
Psychiatric Association, 1998) findet sich die Nikotinabhängigkeit im Kapitel<br />
„Störungen im Zusammenhang mit psychotropen Substanzen“, wobei<br />
zwischen Substanzkonsum (Substanzabhängigkeit und Substanzkonsum)<br />
und substanzinduzierten Störungen (Substanzintoxikation, Substanzentzug,<br />
substanzinduziertes Delir, persistierende substanzinduzierte Demenz etc.)<br />
unterschieden wird. Neben Nikotin werden im DSM-IV elf weitere abhängig<br />
machende Substanzen definiert. Dazu gehören neben Alkohol, Amphetaminen,<br />
Cannabis, Halluzinogenen, Inhalantien, Koffein, Kokain, Opiaten,<br />
Phencyclidine und Sedativa/Hypnotika/Anxiolytika auch multiple Substanzen.<br />
Neben den speziellen Entzugs- und Intoxikationssyndromen jeder einzelnen<br />
Gruppe gibt es in diesem Diagnosesystem auch eine Reihe gemeinsamer<br />
Kriterien, die erfüllt sein müssen, um eine Diagnose stellen zu können.<br />
So gibt es für Substanzabhängigkeit und Substanzmissbrauch ebenso<br />
wie für Substanzintoxikation und Substanzentzug allgemeingültige Kenn-
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
zeichen, die im Folgenden vorgestellt werden, bevor auf die Nikotinabhängigkeit<br />
im Speziellen eingegangen wird.<br />
Allgemeine Kriterien<br />
Unter Substanzabhängigkeit wird „ein unangepasstes Muster von Substanzkonsum<br />
[verstanden, das] in klinisch bedeutsamer Weise zu Beeinträchtigungen<br />
oder Leiden [führt], wobei mindestens drei … Kriterien zu irgendeiner<br />
Zeit in demselben 12-Monats-Zeitraum auftreten“ (American Psychiatric<br />
Association, 1998, S. 99). In Abbildung 1 sind diese Kriterien zusammengestellt.<br />
1. Toleranzentwicklung, definiert durch eines der folgenden Kriterien:<br />
a) Verlangen nach ausgeprägter Dosissteigerung, um einen Intoxikationszustand<br />
oder erwünschten Effekt herbeizuführen,<br />
b) deutlich verminderte Wirkung bei fortgesetzter Einnahme derselben Dosis.<br />
2. Entzugssymptome, die sich durch eines der folgenden Kriterien äußern:<br />
a) Charakteristisches Entzugssyndrom der jeweiligen Substanz (siehe Kriterien A<br />
und B der Kriterien für Entzug von den spezifischen Substanzen),<br />
b) dieselbe (oder eine sehr ähnliche) Substanz wird eingenommen, um Entzugssymptome<br />
zu lindern oder zu vermeiden.<br />
3. Die Substanz wird häufig in größeren Mengen oder länger als beabsichtigt eingenommen.<br />
4. Anhaltender Wunsch oder erfolglose Versuche, den Substanzkonsum zu verringern<br />
oder zu kontrollieren.<br />
5. Viel Zeit für Aktivitäten, um die Substanz zu beschaffen (z.B. Besuch verschiedener<br />
Ärzte oder Fahrt langer Strecken), sie zu sich zu nehmen (z.B. Kettenrauchen) oder<br />
sich von ihren Wirkungen zu erholen.<br />
6. Wichtige soziale, berufliche oder Freizeitaktivitäten werden aufgrund des Substanzkonsums<br />
aufgegeben oder eingeschränkt.<br />
7. Fortgesetzter Substanzkonsum trotz Kenntnis eines anhaltenden oder wiederkehrenden<br />
körperlichen oder psychischen Problems, das wahrscheinlich durch die Substanz<br />
verursacht oder verstärkt wurde (z.B. fortgesetzter Kokainkonsum trotz des<br />
Erkennens kokaininduzierter Depressionen oder fortgesetztes Trinken trotz des Erkennens,<br />
dass sich ein Ulcus durch Alkoholkonsum verschlechtert).<br />
Abbildung 1: Kriterien der Substanzabhängigkeit nach DSM-IV 1<br />
1 aus American Psychiatric Association, 1998, S. 99ff.<br />
21
22<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
Neben den bereits genannten Kriterien wird außerdem in Abhängigkeit vom<br />
Vorliegen oder Nicht-Vorliegen von Toleranzentwicklung oder Entzugserscheinungen<br />
zwischen einer Substanzabhängigkeit mit oder ohne körperliche<br />
Abhängigkeit unterschieden. Zudem wird zwischen sechs verschiedenen<br />
Verlaufsformen differenziert, auf deren Darstellung hier verzichtet<br />
wird.<br />
Unter Substanzmissbrauch wird ein unangepasstes Muster von Substanzkonsum<br />
[verstanden, das] in klinisch bedeutsamer Weise zu Beeinträchtigungen<br />
oder Leiden [führt], wobei sich mindestens eines [von vier] Kriterien<br />
innerhalb desselben 12-Monats-Zeitraum manifestiert“ (American<br />
Psychiatric Association, 1998, S. 103). Diese Diagnose kann nur vergeben<br />
werden, wenn nicht gleichzeitig die Bedingungen für eine Substanzabhängigkeit<br />
vorliegen. Die genannten Kriterien können der Abbildung 2 entnommen<br />
werden.<br />
1. Wiederholter Substanzkonsum, der zu einem Versagen bei der Erfüllung wichtiger<br />
Aufgaben oder Verpflichtungen bei der Arbeit, in der Schule oder zu Hause führt<br />
(z.B. wiederholtes Fernbleiben von der Arbeit und schlechte Arbeitsleistungen in Zusammenhang<br />
mit dem Substanzkonsum, Schulschwänzen, Einstellen des Schulbesuchs<br />
oder Ausschluss von der Schule in Zusammenhang mit Substanzkonsum, Vernachlässigung<br />
von Kindern und Haushalt).<br />
2. Wiederholter Substanzkonsum in Situationen, in denen es aufgrund des Konsums zu<br />
einer körperlichen Gefährdung kommen kann (z.B. Alkohol am Steuer oder das Bedienen<br />
von Maschinen unter Substanzeinfluss).<br />
3. Wiederholte Probleme mit dem Gesetz in Zusammenhang mit dem Substanzkonsum<br />
(Verhaftungen aufgrund ungebührlichen Betragens in Zusammenhang mit dem Substanzkonsum).<br />
4. Fortgesetzter Substanzkonsum trotz ständiger oder wiederkehrender sozialer/zwischenmenschlicher<br />
Probleme, die durch die Auswirkungen der psychotropen<br />
Substanz verursacht oder verstärkt werden (z.B. Streit mit Ehegatten über Folgen der<br />
Intoxikation, körperliche Auseinandersetzungen).<br />
Abbldung 2: Kriterien des Substanzmissbrauchs nach DSM-IV 2<br />
Wie zu Beginn dieses Kapitels bereits erwähnt, gehören die beiden Diagnosen<br />
Substanzintoxikation und Substanzentzug im Gegensatz zu Substanzab-<br />
2 aus American Psychiatric Association, 1998, S. 103
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
hängigkeit und –missbrauch in den Teilbereich der substanzinduzierten<br />
Störungen. Dabei wird unter erstgenannter „die Entwicklung eines reversiblen<br />
substanzspezifischen Syndroms [verstanden], das auf die kurz zurückliegende<br />
Einnahme bzw. den Einfluss der Substanz zurückgeht. Außerdem<br />
werden klinisch bedeutsame unangepasste Verhaltens- oder psychische<br />
Veränderungen, die auf die Wirkung der Substanz auf das Zentralnervensystem<br />
zurückzuführen sind (z.B. Streitsucht, Affektlabilität, kognitive<br />
Beeinträchtigung, beeinträchtigtes Urteilsvermögen, Beeinträchtigungen im<br />
sozialen oder beruflichen Bereich) und die sich während oder kurz nach<br />
dem Substanzkonsum entwickeln“ (American Psychiatric Association,<br />
1998, S. 103f.) als notwendige Bedingungen angeführt. Schließlich wird<br />
gefordert, dass „die Symptome nicht auf einen medizinischen Krankheitsfaktor<br />
oder eine Verletzung [zurückzuführen sind] und … nicht durch eine<br />
andere psychische Störung besser erklärt werden [können]“ (American<br />
Psychiatric Association, 1998, S. 103f.).<br />
Mit Substanzentzug ist die „Entwicklung eines substanzspezifischen Syndroms,<br />
das auf die Beendigung (oder Reduktion) von übermäßigem und<br />
langandauerndem Substanzkonsum zurückzuführen ist“ (American Psychiatric<br />
Association, 1998, S. 104) gemeint. Dieses Syndrom „verursacht in<br />
klinisch bedeutsamer Weise Leiden oder Beeinträchtigungen in sozialen,<br />
beruflichen oder anderen wichtigen Funktionsbereichen“ (American Psychiatric<br />
Association, 1998, S. 104). Gleichzeitig dürfen die Symptome auch<br />
hier „nicht auf einen medizinischen Krankheitsfaktor [zurückzuführen sein]<br />
und können nicht durch eine andere psychische Störung besser erklärt werden“<br />
(American Psychiatric Association, 1998, S. 104).<br />
Kristallisiert sich das Vorliegen einer dieser vier Diagnosen heraus, muss<br />
im nächsten Schritt geprüft werden, durch welche Substanz die Störung<br />
verursacht wurde. Diese Arbeit beschränkt sich im folgenden Abschnitt auf<br />
die Darstellung der spezifischen Kriterien für die Nikotinabhängigkeit.<br />
23
24<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
Spezifische Kriterien der Nikotinabhängigkeit<br />
Im Bereich der Nikotinabhängigkeit wird im DSM-IV zwischen Nikotinabhängigkeit<br />
mit dem Diagnoseschlüssel 305.10 (Störung durch Nikotinkonsum),<br />
dem Nikotinentzug mit der Kodierung 292.0 und der nicht näher<br />
bezeichneten Störung im Zusammenhang mit Nikotin unterschieden, wobei<br />
die beiden letztgenannten zu den nikotininduzierten Störungen gezählt werden.<br />
Zur Stellung der Abhängigkeitsdiagnose müssen die allgemeinen Kriterien<br />
des vorangegangenen Abschnittes erfüllt sein. Die Kriterien für den<br />
Nikotinentzug sind in Abbildung 3 zusammengefasst.<br />
1. Täglicher Konsum von Nikotin, mindestens mehrere Wochen lang.<br />
2. Die plötzliche Beendigung des Nikotinkonsums oder eine Reduktion der Nikotinmenge<br />
führt innerhalb von 24 Stunden zu mindestens vier der folgenden Symptome:<br />
a) Dysphorische oder depressive Stimmung,<br />
b) Schlaflosigkeit,<br />
c) Ablenkbarkeit, Enttäuschung oder Ärger,<br />
d) Angst,<br />
e) Konzentrationsschwierigkeiten,<br />
f) Unruhe,<br />
g) Verminderte Herzfrequenz,<br />
h) Gesteigerter Appetit oder Gewichtszunahme.<br />
3. Die Symptome von Kriterium 2 verursachen in klinisch bedeutsamer Weise Leiden<br />
oder Beeinträchtigungen in sozialen, beruflichen oder anderen wichtigen Funktionsbereichen.<br />
4. Die Symptome gehen nicht auf einen medizinischen Krankheitsfaktor zurück und<br />
können nicht besser durch eine andere psychische Störung erklärt werden.<br />
Abbildung 3: Kriterien des Nikotinentzugs nach DSM-IV 3<br />
Die Kategorie der nicht näher bezeichneten Störung im Zusammenhang mit<br />
Nikotin bildet eine Art Restkategorie, in die alle Störungen eingruppiert<br />
werden, die zwar mit dieser Substanz in Verbindung gebracht werden, jedoch<br />
die Kriterien der bereits dargestellten Diagnosebilder nicht erfüllen.<br />
3 aus American Psychiatric Association, 1998, S. 104
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2.2.2. Internationale statistische Klassifikation der Krankheiten und<br />
verwandter Gesundheitsprobleme (ICD-10)<br />
Im Kapitel V „Psychische und Verhaltensstörungen“ der ICD-10 (Weltgesundheitsorganisation,<br />
2006) findet sich die Nikotinabhängigkeit unter dem<br />
Klassifikationsschlüssel F17 mit der Bezeichnung „Psychische und Verhaltensstörungen<br />
durch Tabak“. Im Gegensatz zum DSM-IV werden hier keine<br />
eigenen Kriterien für die einzelnen Substanzklassen aufgestellt. Zur näheren<br />
Bezeichnung der vorliegenden Störung wird in diesem Diagnosesystem erst<br />
die relevante Substanz identifiziert und dann in einem weiteren Schritt überprüft,<br />
ob eine akute Intoxikation, schädlicher Gebrauch, ein Abhängigkeitssyndrom,<br />
ein Entzugssyndrom, ein Entzugssyndrom mit Delir, eine<br />
psychotische Störung, ein amnestisches Syndrom, ein Restzustand mit verzögert<br />
auftretender psychotischer Störung, sonstige psychische und Verhaltensstörungen<br />
oder eine nicht näher bezeichnete psychische oder Verhaltensstörung<br />
vorliegt. Als psychotrope Substanzklassen gelten im ICD-10<br />
Alkohol, Opioide (Morphin, Heroin etc.), Cannabinoide (Haschisch und<br />
Marihuana), Sedativa oder Hypnotika (Beruhigungs- oder Schlafmittel wie<br />
z.B. Benzodiazepine), Kokain, sonstige Stimulantien einschließlich Koffein,<br />
Halluzinogene (z.B. LSD, Ecstasy), Tabak und flüchtige Lösungsmittel<br />
(z.B. Schnüffelstoffe). Zusätzlich gibt es eine Restgruppe sonstiger psychotroper<br />
Substanzen (Köhler, 2000). In den folgenden Absätzen soll kurz<br />
auf die für Nikotin relevanten Zustandsbilder eingegangen werden.<br />
Die „akute Intoxikation“ oder auch der „akute Rausch“ bezeichnet das Zustandsbild<br />
nach der Einnahme einer psychotropen Substanz und ist durch<br />
Störungen der Bewusstseinslage, der kognitiven Fähigkeiten, der Wahrnehmung,<br />
von Affekt und Verhalten oder von anderen psychophysiologischen<br />
Funktionen und Reaktionen gekennzeichnet. Diese Beeinträchtigungen<br />
müssen dabei in direktem Zusammenhang mit den akuten pharmakologischen<br />
Wirkungen der Substanz stehen. Bis zur vollständigen Rehabilitierung<br />
des Körpers nehmen sie mit der Zeit ab, bei aufgetretenen Gewebeschäden<br />
oder anderen Komplikationen ist jedoch auch ein Weiterbestehen<br />
möglich. Komplikationen im Sinne des ICD-10 können ein Trauma, die<br />
Aspiration von Erbrochenem, Delir, Koma, Krampfanfälle und andere me-<br />
25
26<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
dizinische Folgen sein. Ihre Art ist abhängig von den pharmakologischen<br />
Eigenschaften und der Aufnahmeart der Substanz. Intoxikationen im Sinne<br />
einer Vergiftung sind hier explizit ausgeschlossen.<br />
„Schädlicher Gebrauch“ meint den Konsum psychotroper Substanzen, der<br />
zu einer Gesundheitsschädigung in Form einer körperlichen (z.B. Hepatitis<br />
nach Selbstinjektion) oder einer psychischen Störung (z.B. depressive Episode<br />
durch massiven Alkoholkonsum) führt.<br />
Das „Abhängigkeitssyndrom“ umfasst eine Gruppe von Verhaltens-, kognitiven<br />
und körperlichen Phänomenen, die sich nach wiederholtem Substanzgebrauch<br />
entwickeln. Typischerweise manifestiert sich ein starkes Craving<br />
als der Wunsch, die Substanz einzunehmen. Gleichzeitig bestehen große<br />
Schwierigkeiten den Konsum zu kontrollieren. Meist wird die Substanz<br />
trotz schädlicher Folgen weiter eingenommen. Im Verlauf wird dem Substanzgebrauch<br />
immer mehr Vorrang vor anderen Aktivitäten und Verpflichtungen<br />
gegeben. Neben einer Toleranzerhöhung kann es auch zu körperlichen<br />
Entzugssymptomen kommen. Dieses Störungsbild kann sich sowohl<br />
auf einen einzelnen Stoff beziehen (z.B. Tabak, Alkohol), als auch auf eine<br />
Substanzgruppe (z.B. opiatähnliche Substanzen) oder ein weites Spektrum<br />
pharmakologisch unterschiedlicher Substanzen.<br />
Bei einem „Entzugssyndrom nach absolutem oder relativem Entzug“ einer<br />
psychotropen Substanz handelt es sich um mehrere Symptome aus unterschiedlichen<br />
Bereichen und mit verschiedenem Schweregrad, abhängig von<br />
der zuletzt eingenommen Substanzart und Dosis, die über einen längeren<br />
Zeitraum konsumiert wurde. Die Beschwerden sind zeitlich begrenzt, können<br />
aber durch symptomatische Krampfanfälle kompliziert werden.<br />
Bei einem „Entzugssyndrom mit Delir“ kommt als weitere Komplikation zu<br />
dem eben beschriebenen Zustandsbild ein Delir hinzu. Im Bereich der Nikotinabhängigkeit<br />
spielt diese Diagnose jedoch keine Rolle, so dass sie lediglich<br />
der Vollständigkeit wegen aufgeführt werden soll.<br />
Ähnlich ist es im Bereich der „psychotischen Störung“, die eine Gruppe<br />
psychotischer Phänomene umschreibt, die während oder nach dem Sub-
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
stanzgebrauch auftreten, jedoch nicht durch akute Intoxikation erklärt werden<br />
können. Halluzinationen, die meist akustisch sind, Wahrnehmungsstörungen,<br />
Wahnideen, psychomotorische Störungen, sowie abnorme Affekte<br />
sind typische Symptome, die im Rahmen dieses Störungsbildes auftreten<br />
können. In den bei einer Nikotinabhängigkeit üblichen eingenommenen<br />
Dosisspannen sind derartige Phänomene jedoch nicht zu erwarten.<br />
Auch das „amnestische Syndrom“, das mit einer ausgeprägten Beeinträchtigung<br />
des Kurz- und Langzeitgedächtnisses einhergeht, besitzt bei der Nikotinabhängigkeit<br />
keine klinische Bedeutung. Das Ultrakurzzeitgedächtnis ist<br />
bei allen Substanzen meist nicht in Mitleidenschaft gezogen. Das Kurzzeitgedächtnis<br />
mit Störungen des Zeitgefühls, des Zeitgitters und Lernschwierigkeiten<br />
ist dagegen bei Einnahme anderer psychotroper Substanzen typischerweise<br />
am stärksten gestört. Andere kognitive Funktionen sind dagegen<br />
meist relativ gut erhalten.<br />
Die als „Restzustand und verzögert auftretende psychotische Störung“ umfasst<br />
alkohol- und substanzbedingte Veränderungen der kognitiven Fähigkeiten,<br />
des Affekts, der Persönlichkeit oder des Verhaltens, die eine direkte<br />
Substanzeinwirkung überdauern. Der Beginn dieser Veränderungen muss in<br />
unmittelbarem Zusammenhang mit dem Gebrauch der psychotropen Substanz<br />
stehen. Auch diese Kategorie ist für die Nikotinabhängigkeit nicht von<br />
Relevanz.<br />
Die beiden Kategorien „Sonstige psychische und Verhaltensstörungen und<br />
Nicht näher bezeichnete psychische und Verhaltensstörung“ werden nicht<br />
näher ausgeführt und dienen als Restkategorien für Störungsbilder, die nicht<br />
in die bereits vorgestellten Zustandsbilder eingeteilt werden können.<br />
27
28<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2.2.3. Vergleich DSM-IV und ICD-10<br />
Sowohl das ICD-10 als auch das DSM-IV definieren die Abhängigkeitserkrankung<br />
als Unfähigkeit zur Abstinenz mit zusätzlichen Merkmalen, wie<br />
dem Verlust der Kontrolle über den geregelten Substanzkonsum, einer Toleranzentwicklung<br />
bezüglich der Substanzwirkungen und dem Auftreten<br />
körperlicher Entzugssymptome. Beide konzentrieren sich auf eine symptomatische<br />
Beschreibung der Störung, die keine Auskunft über die Äthiopathogenese<br />
oder das Wesen der Abhängigkeit erlaubt. Die Abgrenzung des<br />
abhängigen Konsums vom normalen Konsum fällt mit Hilfe der in beiden<br />
Diagnosesystemen vergleichbaren Kriterien nicht leicht, da die deskriptiven<br />
Merkmale hohe Konsummengen, situative Steigerung des Konsums, Symptome<br />
der Intoxikation und körperliche Schäden als Folge wiederholter<br />
Einnahme weder notwendig noch hinreichend für eine Abhängigkeit sind<br />
(Balfour & Fagerstrom, 1996; Hughes, 2006). Das aktuelle Krankheitskonzept<br />
geht außerdem davon aus, dass die Störung irreversibel ist, ein kontrollierter<br />
Konsum der Substanz entsprechend zeitlebens nicht mehr möglich<br />
sei.<br />
Die Nikotinabhängigkeit wird auch deswegen in beiden Systemen als<br />
Krankheit bezeichnet, weil sie mit Leid, Funktionseinschränkungen und<br />
drohendem Tod verbunden ist. Entsprechende Korrelate des abhängigen<br />
Verhaltens von Rauchern sind bisher jedoch nur zum Teil nachweisbar. So<br />
konnte für das Kriterium Kontrollverlust bisher keine neurobiologische<br />
Entsprechung gefunden werden (Hughes, 2006). Auch beim Rückfall stellt<br />
sich die Frage, ob dieser gegen den bewussten Willen – quasi organisch<br />
bedingt – erfolgt oder ob der Betroffene eine bewusste Entscheidung zur<br />
Einnahme der Substanz trifft. Weiterhin bleibt zu bemerken, dass die Definition<br />
der Nikotinabhängigkeit in der ICD-10 dichotom erfolgt. In der Realität<br />
handelt es sich jedoch um ein Kontinuum: manche Raucher rauchen<br />
wenig, inhalieren auch fast nicht, andere rauchen mehr als 50 Zigaretten am<br />
Tag und inhalieren tief, rauchen sogar in der Nacht. Eine dichotome Einteilung<br />
scheint entsprechend nicht möglich zu sein.
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
Abschließend bleibt zu bemerken, dass sich die Diagnose der Nikotinabhängigkeit<br />
im alltäglichen Umgang mit Patienten schwierig gestaltet, da<br />
sich die meisten Menschen auf einem Kontinuum zwischen abhängigem<br />
und nichtabhängigem Verhalten einordnen lassen (Balfour & Fagerstrom,<br />
1996). Dabei befinden sich die meisten Raucher nicht an einem der beiden<br />
Extrempole, eine klare Diagnose ist jedoch nur dort möglich (Lewis, 1994).<br />
2.3. Geschichte des Rauchens<br />
Wie in den bisherigen Kapiteln bereits deutlich geworden ist und in den<br />
nächsten Abschnitten, in denen auf die Folgen des Tabakkonsums eingegangen<br />
wird (s. Kap. 3.7), noch stärker in den Vordergrund treten wird,<br />
handelt es sich bei Nikotin um eine hochgiftige Substanz, deren Einnahme<br />
im schlimmsten Falle auch zum Tod führen kann. Es stellt sich also die<br />
Frage, wie es möglich war, dass sich eine derart gefährliche Gewohnheit<br />
wie das Rauchen über Jahrhunderte hinweg halten und sich in alle Regionen<br />
der Erde ausbreiten konnte. Deshalb sollen im dritten Kapitel auch die positiven<br />
Wirkungen von Nikotin näher dargestellt werden. In diesem Kapitel<br />
erfolgt jedoch zunächst, angelehnt an Walther (1982), ein kurzer historischer<br />
Überblick über die Erfolgsgeschichte des Nikotins.<br />
Die Herkunft des Wortes Tabak ist bis heute nicht ganz klar. Man geht<br />
davon aus, dass es ursprünglich von den Antillen stammt, wo Rauchrohre<br />
als tabacco bezeichnet wurden. Von Oviedo und Las Casas wurde die Bezeichnung<br />
auf die Pflanze und ihre Blätter übertragen und setzte sich gegen<br />
hunderte anderer Begriffe durch. Ursprünglich wuchs die Tabakpflanze, die<br />
den Namen Nicotiana tabacum trägt, nur auf dem amerikanischen Kontinent,<br />
den Sunda-Inseln und in Australien. Vor der Ankunft der Europäer<br />
war der Nutzanbau sogar ausschließlich auf Südamerika beschränkt. Die<br />
östlichen Täler der bolivianischen Anden bildeten die Heimat des Gewächses,<br />
das sich nach und nach innerhalb der tropischen Regionen Südamerikas<br />
ausbreitete. Dass es immer mehr Land mit unterschiedlichsten Boden- und<br />
Klimabedingungen für sich erobern konnte, beruht auf seiner großen Anpassungsfähigkeit.<br />
Für die Maya-Indianer war der Tabak ein Geschenk der<br />
Götter, das sich entsprechend auch als bestes Mittel etablierte, um mit die-<br />
29
30<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
sen in Kontakt zu treten und Energie von ihnen zu erhalten bzw. weniger<br />
Hunger zu verspüren. Mit der Ankunft Kolumbus´ im Jahr 1492 breitete<br />
sich die Nutzung nicht nur in den Norden des Kontinents, sondern auch bis<br />
nach Europa aus. Wahrscheinlich brachten zu Beginn des 16. Jahrhunderts<br />
heimkehrende Spanier und Portugiesen den Tabak in ihre Heimatländer mit,<br />
wo Nicotiana tabacum zunächst als Zierpflanze in den Gärten wuchs und<br />
später als Allheilmittel in jeder Apotheke zum Rauchen, Schnupfen oder für<br />
Umschläge erhältlich war. Jean Nicot, von 1559 bis 1561 französischer<br />
Gesandter in Lissabon, brachte die Pflanze nach Paris und überzeugte den<br />
französischen Hof von ihrer wunderbaren Heilfähigkeit. Ihm zu Ehren<br />
nannte Lièbeault 1570 in seinem Buch „L´agriculture et maison rustique“<br />
die Tabakpflanze nicotiana. In der Folge breitete sie sich von Frankreich<br />
über ganz Europa aus (Hess, 1987). Im Laufe der Zeit entdeckte man auch<br />
die Eigenschaften, die den Tabak als Genussmittel qualifizierten. Anfang<br />
des Folgejahrhunderts brachten wahrscheinlich erneut portugiesische Seeleute<br />
und später holländische Einwanderer den Tabak nach Afrika. Durch<br />
gute Handelskontakte zwischen Portugal, Spanien und Ost- bzw. Südostasien<br />
gelangte er auch dorthin. Im 17. Jahrhundert wurde Nikotin als Wundermittel<br />
gegen die Pest eingesetzt. Die Napoleonischen Kriege und der 30jährige<br />
Krieg unterstützten die Verbreitung der Pflanze zusätzlich. Parallel<br />
dazu wurden jedoch auch erste kritische Stimmen laut. Der englische König<br />
Jakob I. begann in eben diesem Jahrhundert als erster eine Antiraucherkampagne<br />
mit Schmähschriften. Auch der damalige Papst drohte 1642 allen in<br />
der Kirche rauchenden Menschen mit Exkommunizierung. Diese Drohung<br />
galt vor allem für während der Messe rauchende Priester. Die Drohung<br />
zeigte jedoch keine Effekte, die Priester führten als Argument die Reduktion<br />
fleischlicher Lust an, was heute durch die negativen Wirkungen des<br />
Tabaks auf die Potenz auch belegt ist. Ende des 17.Jh. gab es in fast allen<br />
Ländern der Welt Rauchverbote, die wie die Drohungen des Papstes trotz<br />
hoher Strafen keine Wirkung erzielen konnten. So ließ z.B. Sultan Murad<br />
IV. während seiner Regierungszeit in fünf Jahren 25000 Raucher hinrichten.<br />
In anderen Ländern wurden Raucher ausgepeitscht oder die Lippen aufgeschnitten,<br />
sie wurden verbannt, das Vermögen wurde konfisziert oder sogar<br />
die Nase abgeschnitten. In der Türkei wurden Tabakhändler sogar an Ort<br />
und Stelle enthauptet. Trotzdem rauchten die Menschen unbeeindruckt
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
weiter. Nach dem Krimkrieg startete der Tabak schließlich seinen Siegeszug<br />
in den Westen, wo er im ersten und im zweiten Weltkrieg noch einmal eine<br />
Blütezeit erlebte. Zu dieser Zeit waren die Zigaretten gewöhnlich noch<br />
filterlos. Fabrikanten begannen dann nach und nach Filter zu bauen, um den<br />
verlorenen Tabakanteil im nicht gerauchten Teil der Zigarette zu reduzieren<br />
und das Rauchen für Frauen attraktiver zu machen, die sich über gelbe Finger<br />
beschwerten. Nach dem Gesundheitsreport des Surgeon General 1964,<br />
der die Ergebnisse verschiedener großer systematischer Untersuchungen zu<br />
gesundheitlichen Schäden des Rauchens zusammenfasste, stieg das Interesse<br />
an der Reduktion der Teermenge und die Tabakindustrie reagierte mit der<br />
Entwicklung mehrerer Filtertypen. Heute rauchen mehr als 90% aller Raucher<br />
Filterzigaretten. Nach dem Report fiel der Zigarettenkonsum außerdem<br />
deutlich ab, dennoch raucht heute noch jeder vierte Erwachsene. Entsprechend<br />
ist das Rauchen auch heute noch eine gute wirtschaftliche Einnahmequelle,<br />
so dass die Nicotiana tabacum an verschiedensten Orten der Welt<br />
angebaut wird. Dazu zählen die Ostküste Nordamerikas, Mittelamerika,<br />
Brasilien, Argentinien, Syrien, Palästina, Ostafrika und asiatische Monsungebiete.<br />
2.4. Inhaltsstoffe des Tabaks<br />
In einem Überblick über eine Vielzahl von Studien, die sich mit den abhängig<br />
machenden Bestandteilen von Zigaretten beschäftigten, zog Russel<br />
(1978) die Schlussfolgerung, dass Nikotin der Abhängigkeit erzeugende<br />
Inhaltsstoff des Tabakrauchs sein muss. Als Grundlage für diese Annahme<br />
zog er unter anderem Arbeiten heran, in denen die Zusammensetzung der<br />
Zigarette konstant gehalten und lediglich der Nikotingehalt variiert wurde.<br />
In Folge der Variation kam es zu einer veränderten Menge gerauchter Zigaretten<br />
und zu einer unterschiedlichen Inhalationstiefe. Nikotin wurde jedoch<br />
erstmals bereits 1828 von den Chemie- und Medizinstudenten Posselt und<br />
Raimann isoliert und als wichtigster Wirkstoff des Tabaks postuliert. Damals<br />
konnten sie ihre Annahme jedoch noch nicht belegen (Hess, 1987).<br />
Die Herstellung des Tabaks, der in der Zigarette enthalten ist, ist ein sehr<br />
komplexer und arbeitsintensiver Prozess, der hundertmal so aufwendig ist<br />
31
32<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
wie Weizenanbau. Die Pflanze produziert Nikotin in den Blättern, um Insektenfraß<br />
abzuwehren. Deswegen müssen die nikotinfreien Blüten zunächst<br />
entfernt werden. Anschließend wird der verbleibende Rest getrocknet<br />
und fermentiert, was zu einem Absinken des Nikotinanteils um 70%<br />
führt. Entsprechend sind Industriezigaretten nikotinärmer als das Rauchen<br />
von Tabakblättern (Dahlke & Dahlke, 2000).<br />
Generell teilt man den Tabakrauch in zwei Anteile auf: Den Hauptstromrauch,<br />
der vom Raucher inhaliert wird und den Nebenstromrauch, der von<br />
der Spitze der Zigarette entweicht und der deutlich gefährlichere Teil ist. Er<br />
enthält z.B. einen um 3,4fach höheren Anteil an Benzpyren, das das stärkste<br />
bekannte Karzinogen darstellt (Hess, 1987). Auch die Nikotinkonzentration<br />
liegt im Nebenstromrauch 50mal höher.<br />
Der Tabakrauch besteht aus flüchtigen (95% des Gewichts) und korpuskularen<br />
Stadien. Im flüchtigen Stadium konnten 500 Gaskomponenten identifiziert<br />
werden. Dazu zählen Stickstoff, CO, CO2, Ammoniak, Blausäure und<br />
auch Benzin. Im korpuskularen Stadium befinden sich circa 3500 Komponenten,<br />
wobei der Hauptbestandteil Nikotin ist. Weitere Komponenten bilden<br />
Wasser, Nornikotin, Anatabin und Anabasin. Den Rest dieses Stadiums<br />
bezeichnet man als Teer. Dieser besteht unter anderem aus polynuklearem<br />
aromatischem Kohlenwasserstoff, N-Nitrosaminen und aromatischen Aminen.<br />
Neben den bereits genannten Bestandteilen enthält der Tabakrauch<br />
unter anderem die krebsfördernden Substanzen Acrolin, Formaldehyd, N-<br />
Nitrosonornikotin, Anilin, Cadmium, Nickel, Hydrazin, Benz(a)antrazen,<br />
N-Nitrosopyrrolidin, N-Dimenthylnitrosamin, N-Diethylnitrosamin, N-<br />
Ethyl-N-methylnitrosamin und Vinylchlorid (Industriegewerkschaft Metall,<br />
1992). Schließlich werden dem Tabak auch Geschmacksstoffe wie Lakritze,<br />
Coca, Fruchtsäfte, Gewürze und synthetische Erzeugnisse hinzugefügt, da<br />
die Zigaretten sonst zu fad schmecken würden (Hess, 1987).
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
2.5. Nikotinenantiomere und ihre Eigenschaften<br />
2.5.1. Nikotinenantiomere<br />
Nikotin besitzt die chemische Bezeichnung [(s)-3-(1-Methyl-2pyrrolidinyl)pyridin]<br />
und ist ein tertiäres Amin, das als Stereoisomer S-(-)-<br />
Nikotin resorbiert wird. Es handelt sich um ein wasser- und fettlösliches<br />
toxisches Alkaloid, das neben anderen Alkaloiden wie Nor-Nicotin und<br />
Anabasin in den Blättern der Tabakpflanze enthalten ist. Es besteht aus<br />
Pyridin und einem Pyrrolidinring (s. Abb. 4).<br />
Abbildung 4: Chemische Struktur des Nikotins<br />
Bisher wurden zwei Isomere entdeckt, von denen S-(-)-Nikotin als das aktive<br />
Isomer gilt. Unter anderem bewirkt es auch eine 16fache Blutdruckerhöhung<br />
im Vergleich zum weniger aktiven Isomer R-(+)-Nikotin (Aceto,<br />
Martin, Uwaydah, May, Harris, Izazola-Conde, Dewey, Bradshaw & Vincek,<br />
1979). Deswegen befindet sich auch vorwiegend diese Variante im<br />
Tabak. Das zweite Enantiomer entsteht durch Racemisierung während des<br />
Rauchens. Deswegen ist auch ein kleiner Teil der R-(+)-Nikotin-Variante<br />
im Tabakrauch zu finden. Es handelt sich jedoch um einen schwachen cholinergen<br />
Rezeptoragonisten. S-(-)-Nikotin bindet mit 50 bis 100fach stärkerer<br />
Affinität an Nikotinrezeptoren als das weniger aktive R-(+)-Enantiomer<br />
(Balfour & Fagerstrom, 1996). Auch die Toxizität für S-(-)-Nikotin gilt als<br />
doppelt so hoch wie für R-(+)-Nikotin. Außerdem ist das Intoxikationsmuster<br />
unterschiedlich: S-(-)-Nikotin löst eine Erregung aus, die für R-(+)-<br />
Nikotin nicht zu beobachten ist, und ist direkt vor den tödlichen Krämpfen<br />
33
34<br />
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
paralytischer. R-(+)-Nikotin produziert Zittern, das mit der Zeit aber wieder<br />
verschwindet. In höheren Dosen führt es ebenfalls zu zunehmendem Tremor<br />
und schlussendlich zu Erregung und Krämpfen (Holmstedt, 1990).<br />
Menschen sind in der Lage qualitativ zwischen den beiden Isomeren zu<br />
unterscheiden (Walker, Kendal-Reed, Keiger, Bencherif & Silver, 1996).<br />
Thuerauf, Kaegler, Renner, Barocka und Kobal (2000) fanden bei Rauchern<br />
und Nichtrauchern zwar keinen Unterschied in den Riechschwellen zwischen<br />
den beiden Gruppen und den beiden Substanzen, es ergaben sich aber<br />
Differenzen in der hedonischen Einschätzung. R-(+)- Nikotin wurde von<br />
beiden Untersuchungskollektiven als unangenehm eingeschätzt, S-(-)-<br />
Nikotin wurde von den Rauchern als angenehmer empfunden. Jedoch trat<br />
dieser Unterschied nur ein, wenn die beiden Enantiomere in trigeminalen<br />
Konzentrationen verabreicht wurden. In einer weiteren Untersuchung mit<br />
einem Elektroolfaktogramm an Fröschen fanden die Autoren ebenfalls keine<br />
Unterschiede zwischen den beiden Enantiomeren. Da sie geringe und<br />
damit olfaktorische Konzentrationen verabreicht hatten, gingen sie davon<br />
aus, dass die in früheren Untersuchungen festgestellte unterschiedliche<br />
Wahrnehmung der beiden Nikotinsorten nicht über das olfaktorische System<br />
vermittelt sein kann (Thürauf, Renner & Kobal, 1995). In der Folge<br />
arbeiteten sie mit trigeminalen Konzentrationen und fanden mit Hilfe negativer<br />
Mucosapotentiale stereospezifische Aspekte im trigeminalen System.<br />
Dazu gehörten stärkere Antworten, höhere Intensitätseinschätzungen und<br />
geringere trigeminale Schwellen für S-(-)-Nikotin. Sie schlossen daraus,<br />
dass es auf den trigeminalen nozizeptiven Fasern spezifische stereoselektive<br />
Rezeptoren für die beiden Enantiomere geben muss (Thuerauf, Kaegler,<br />
Dietz, Barocka & Kobal, 1999). Im weiteren Verlauf der Arbeit wird der<br />
besseren Lesbarkeit wegen auf die chemisch korrekte Schreibweise verzichtet<br />
und von S- und R-Nikotin gesprochen<br />
2.5.2. Eigenschaften des Nikotins<br />
Im nicht-ionisierten Zustand handelt es sich bei Nikotin um eine schwache<br />
Base, die Membranen passieren kann, z.B. auch die Mundschleimhaut (Benowitz,<br />
1988). In saueren Umgebungen wie dem Tabakrauch mit einem pH-
Nikotinabhängigkeit – Geschichte, Hintergründe und Grundlagen<br />
Wert von 5,5 ist die Durchquerung von Membranen jedoch nicht möglich.<br />
Deswegen erfolgt die Absorption des Nikotins in das Blut beim Rauchen zu<br />
95% über den Alveolärraum der Lunge (Huber, 1992). Durch die Veränderung<br />
von Inhalations- und Rauchtechniken kann der Nikotingehalt zusätzlich<br />
variiert werden. Nach der Aufnahme in den Kreislauf verbreitet sich<br />
das Nikotin schnell in verschiedene Gewebe. Nach ungefähr 7,5 Sekunden<br />
erreicht es das Gehirn bereits in hohen Konzentrationen. Heroin braucht<br />
nach einer Injektion dagegen 14 Sekunden, um an seinem Wirkungsort<br />
anzukommen (Warburton, 1985).<br />
Da verschiedene Autoren eine zwei- bis sechsfach erhöhte Konzentration in<br />
den Arterien gegenüber den Venen festgestellt haben, scheint es dennoch<br />
schnell zu einem Rückgang der Nikotinmenge in Plasma und Gehirn zu<br />
kommen, was auf die rasche Ausbreitung in peripheres Gewebe und körpereigene<br />
Eliminationsmechanismen zurückgeführt wird (Horstmann, 1989).<br />
Nikotin und seine Metaboliten werden mit einer Halbwertszeit von 2 Stunden<br />
von der Niere aus dem Körper ausgeschieden. Es häuft sich jedoch über<br />
vier bis sechs Stunden an und bleibt so über Nacht im Körper (Zevin &<br />
Benowitz, 2000).<br />
Der Abbau des Nikotins erfolgt zu 70% hepatisch, das heißt über die Leber,<br />
und wird zu trans-3´-Hydroxycotinin und Nikotin-1´N-oxid abgebaut (Benowitz<br />
& Jacob, 1993). Wenn der pH-Wert im Urin säuerlich ist, können<br />
die Abbauprodukte auf diesem Weg sogar noch rascher aus dem Kreislauf<br />
entfernt werden. Auch die Aufnahme von Nahrung senkt den Nikotinspiegel<br />
deutlich, was eine Erklärung für die direkte Assoziation von Essen und<br />
Rauchen bei vielen Konsumenten darstellen könnte (Benowitz, 1988). Cotinin,<br />
eines der Hauptmetaboliten des Nikotins, hat eine wesentlich höhere<br />
Halbwertszeit (14 bis 20 Stunden) und wird deswegen auch als Marker für<br />
Nikotinkonsum herangezogen. Da Nikotin und seine Metaboliten wasserlöslich<br />
sind, können sie außerdem auch in der Muttermilch von stillenden Müttern<br />
nachgewiesen werden (Barthwell, 1994).<br />
35
Neurobiologie der Nikotinabhängigkeit<br />
3. Neurobiologie der Nikotinabhängigkeit<br />
Lange Zeit wurden Schwierigkeiten, mit dem Rauchen aufzuhören, als reine<br />
Willensschwäche interpretiert, die nur bei charakterschwachen Menschen<br />
auftreten würden (Ernst, 1989). Leider hält sich diese Vorstellung zum Teil<br />
bis in die heutige Zeit, was sich unter anderem auch darin widerspiegelt,<br />
dass die Krankenkassen Raucherentwöhnungen nur unter bestimmten Bedingungen<br />
bezuschussen und in diesen Fällen die Kosten nur in seltenen<br />
Fällen komplett übernehmen. Neuere Forschungsergebnisse und daraus<br />
resultierende Theorien betonen entgegen alten eindimensionalen Vorstellungen<br />
von der Nikotinabhängigkeit den Einfluss verschiedenster Faktoren<br />
auf den Beginn und die Aufrechterhaltung des Rauchens. Dazu gehören<br />
neben individuellen Merkmalen wie life events (z.B. Scheidung, Tod eines<br />
Angehörigen) und frühkindlichen, sowie adoleszenten Lernerfahrungen<br />
auch gesellschaftliche Rahmenbedingungen wie z.B. die Verfügbarkeit der<br />
Substanz, eine permissive Haltung der Gesellschaft, sowie Einflüsse der<br />
unmittelbaren Lebensumgebung und des sozialen Bezugsraums (Minneker<br />
& Buchkremer, 1989). Auch biologische Prädispositionen im Sinne einer<br />
hereditären oder erworbenen spezifischen, funktionalen oder veränderten<br />
Sensitivität des Individuums, neuromodulatorische Veränderungen durch<br />
den Konsum und die unmittelbare psychotrope Wirkung des Suchtstoffs<br />
werden in neuerer Zeit als wichtige Einflussgrößen miteinbezogen, so dass<br />
man inzwischen von biopsychosozialen Erklärungsmodellen spricht. In den<br />
folgenden Abschnitten erfolgt eine Beschränkung auf die Beschreibung<br />
psychologischer und neurobiologischer Aspekte in Anlehnung an Heinz und<br />
Batra (2003), da eine erschöpfende Darstellung aller möglichen Einflussfaktoren<br />
aufgrund der Komplexität des Störungsbildes einerseits zum aktuellen<br />
Zeitpunkt nicht möglich ist und die Darstellung der sozialen Aspekte, sowie<br />
entwicklungsgeschichtlicher Faktoren inklusive möglicher life events den<br />
Rahmen dieser Arbeit sprengen würde.<br />
37
38<br />
3.1. Acetylcholinrezeptoren<br />
Neurobiologie der Nikotinabhängigkeit<br />
In den letzten Jahrzehnten konnte die Forschung eine herausragende Rolle<br />
des Acetylcholinrezeptors für die Wirkweise des Nikotins identifizieren. Es<br />
handelt sich um phylogenetisch sehr alte Rezeptoren, die sich auch bei wirbellosen<br />
Tieren ausbilden (Leonhard & Bertrand, 2001). Unterschieden<br />
wird entsprechend der natürlich vorkommenden Liganden Nikotin und<br />
Muscarin zwischen nikotinergen und muskarinergen Acetylcholinrezeptoren.<br />
Nikotin bindet wie bereits erwähnt mit hoher Affinität an erstgenannten<br />
und entfaltet so wahrscheinlich seine zentralen und peripheren Wirkungen.<br />
Diese Annahme legen verschiedene experimentelle Studien an Tier und<br />
Mensch nahe, in denen mit Hilfe der beiden Nikotinantagonisten Mecamylamin<br />
und Di-Hydro-Beta-Erythroidin die Wirkungen des Suchtstoffs an<br />
diesen Rezeptoren blockiert werden und sich so die positiven Wirkungen in<br />
Folge der Gabe von Nikotin nicht mehr uneingeschränkt entfalten konnten<br />
(Nemeth-Coslett, Henningfield, O´Keeffe & Griffiths, 1986; Watkins, Epping-Jordan,<br />
Koob & Markou, 1999). Nikotinerge Acetylcholinrezeptoren<br />
finden sich sowohl prä- als auch postsynaptisch an Neuronen und Muskelzellen.<br />
Im Zentralnervensystem werden sie vor allem im Hippocampus<br />
ausgebildet (Hunt & Schmidt, 1978). Leonhard und Bertrand (2001) gehen<br />
davon aus, dass über 45% der Interneurone im Hippocampus mit ihnen<br />
ausgestattet sind. Sie sind Teil einer strukturell verbundenen Superfamilie<br />
von ligandengesteuerten Ionenkanälen, die sich von spannungsgesteuerten<br />
Ionenkanälen abgrenzen lassen (Balfour & Fagerstrom, 1996; Riljak &<br />
Langmeier, 2005). Ihre Aktivierung erfolgt sehr schnell, meist innerhalb<br />
weniger Millisekunden und die Mehrzahl der Rezeptoren sind exzitatorisch<br />
(Arneric, 2000).<br />
Je nach Lokalisation und Anordnung der Rezeptorproteine erfüllen sie unterschiedliche<br />
Funktionen. Neuronale Varianten bestehen aus fünf Untereinheiten,<br />
die als Pentamer aus Glykoproteinen angeordnet sind (Mansvelder,<br />
De Rover, McGehee & Brusaard, 2003). Jedes Rezeptorprotein besitzt<br />
eine Polypeptidkette, die sich viermal durch die Membran zieht (s. Abb. 5),<br />
wobei die zweite Schleife die Innenwand des Kanals bildet. Diese bildet<br />
einen trichterförmigen Kanal, durch den nach Bindung eines Agonisten der
Neurobiologie der Nikotinabhängigkeit<br />
Ionentransport durch die Zellmembran erfolgen kann. In der Folge kommt<br />
es zu einer Depolarisation und erhöhter Exzitabilität (Mansvelder et al.,<br />
2003).<br />
Abbildung 5: Struktur der Acetylcholinrezeptoren 4<br />
Bisher wurden fünf Rezeptorsubtypen identifiziert, die in a-, b-, c-, d- und<br />
e-Einheiten kategorisiert wurden (Arneric, 2000). Für die Nikotinabhängigkeit<br />
werden jedoch bisher nur die a- und b-Subtypen als relevant erachtet.<br />
Jede a-Untereinheit besitzt eine Bindungsstelle für Acetylcholin, an der bei<br />
der nikotinergen Variante auch Nikotin, Kalziumionen, nichtkompetitive<br />
Agonisten (z.B. Physiostigmin, Galanthamin) und verschiedene Inhibitoren<br />
(z.B. Stereoide, Dihydropyridine, Dihydro-b-erythroidin, Arachidonsäure,<br />
Medikamente wie z.B. Mecamylamin) andocken und die Rezeptorfunktion<br />
beeinflussen können. b-Subeinheiten scheinen zum einen das Ausmaß zu<br />
bestimmen, in dem Agonisten und Antagonisten die Kanäle wieder freigeben<br />
und zum anderen in wie weit sich die Kanäle nach Ligandenbindung<br />
öffnen (Papke, 1993).<br />
Wenn Nikotin mit Acetylcholinrezeptoren eine Bindung eingeht, öffnet sich<br />
der Ionenkanal durch die Änderung der Konformation und es folgt wie oben<br />
beschrieben ein signifikanter Kalziumioneneinstrom (Tsuneki, Klink, Korn<br />
& Changeux, 2000). Der Anstieg des intrazellulären Kalziums an präsynaptischen<br />
nikotinergen Acetylcholinrezeptoren löst eine Signalantwort der<br />
4 aus Scheffel-Gymnasium, 2009<br />
39
40<br />
Neurobiologie der Nikotinabhängigkeit<br />
aktivierten Zelle aus und führt zu einer erhöhten Transmission an nachgeschalteten<br />
dopaminergen, glutamatergen und cholinergen Synapsen (McGehee,<br />
Heath, Gelber, Devay & Role, 1995).<br />
Bislang wurden 16 verschiedene Subtypen von nikotinergen Acetylcholinrezeptoren<br />
identifiziert, die aus unterschiedlichen Proteinketten aufgebaut<br />
sind. Beim Menschen handelt es sich dabei um a- (a2-a8) und b-Ketten<br />
(b2-b4), wobei sieben der identifizierten a- und drei der bekannten b-<br />
Varianten im Zentralnervensystem gefunden wurden. Je nach Aufbau der<br />
Rezeptorproteine in einer homomeren, das heißt in einer aus identischen<br />
Proteinen bestehenden Anordnung, oder in einer heteromeren, also in einer<br />
aus verschiedenen Subeinheiten zusammengesetzten Konstellation, entstehen<br />
verschiedene Rezeptorklassen. Die homomere Variante existiert, soweit<br />
bis heute bekannt ist, jedoch nur in Verbindung mit den Subeinheiten a7,<br />
a8 und a9. Die meisten identifizierten Rezeptoren im Gehirn bestehen<br />
vorwiegend aus a4-, a7- und b2-Untereinheiten. Letztgenannte finden sich<br />
am häufigsten im Nucleus Caudatus, Putamen und Hippocampus, a4-<br />
Rezeptorproteine vor allem im Kortex (Leonhard & Bertrand, 2001) und<br />
a7-Varianten im Geniculatum und Thalamus (Agulhorn, Abitbol, Bertrand<br />
& Malafosse, 1999). Der b2-Subeinheit wird die Verantwortung für die<br />
Vermittlung positiver verhaltensverstärkender Wirkungen von Nikotin<br />
(Maskos, Molles, Pons, Besson, Guiard, Guilloux, Evrard, Cazala, Cormier,<br />
Mameli-Engvall, Dufour, Cloez-Tayarani, Bemelmans, Mallet, Gardier,<br />
David, Faure, Granon & Changeux, 2005; Picciotto, Zoll, Rimondini, Léna,<br />
Marubio, Pich, Fuxe & Changeux, 1998) und somit eine wesentliche Funktion<br />
bei der Ausbildung der Abhängigkeit zugesprochen. Untersuchungen<br />
bei Knockout-Mäusen ohne b2-Ketten stützen diese These. Es zeigte sich<br />
eine geringere Verstärkerwirkung von Nikotin bei diesen Tieren (Picciotto<br />
et al., 1998), so dass auf eine Reduktion der Nikotinrezeptorbindungsstellen<br />
im Zentralnervensystem durch die Ausschaltung des b2-<br />
Acetylcholinrezeptorgens geschlossen wurde. a7-Acetylcholinrezeptoren<br />
finden sich hingegen spezifisch auf den GABAergen Interneuronen des<br />
Hippocampus, was zu der Vermutung geführt hat, sie könnten an der Filterung<br />
von sensorischen Informationen im Bereich dieser Hirnregion beteiligt<br />
sein.
Neurobiologie der Nikotinabhängigkeit<br />
Verschiedene Rezeptorklassen interagieren auf unterschiedliche Art mit<br />
Nikotin. Dem a4b2-Subtyp (s. Abb. 6), der vor allem in mesolimbischen<br />
Arealen und im Cortex angesiedelt ist, wird die höchste Affinität für Nikotin<br />
attestiert. Deswegen wird er auch am stärksten mit der Abhängigkeitsentwicklung<br />
assoziiert (Mansvelder et al., 2003). Die Bindungsfähigkeit der<br />
a7-Rezeptorklasse ist dagegen deutlich geringer. Die Stimulation durch<br />
Nikotin führt zudem je nach Andockstelle zu einer unterschiedlich stark<br />
ausgeprägten Desensitisierung und einer damit verbundenen Inaktivierung<br />
der verschiedenen Subtypen (Pidoplichko, DeBiasi, Williams & Dani,<br />
1997), die länger anhält als nach Kontakt mit dem natürlichen Liganden<br />
Acetylcholin. Von einer Inaktivierung betroffen sind die Rezeptorproteine<br />
a2, a4 und a7, a3- und a6-Untereinheiten bleiben dagegen im aktiven<br />
Zustand (Olale, Gerzanih, Kuryatov, Wang & Lindstrom, 1997). Wie bereits<br />
oben erwähnt ist der a4b2-Rezeptortyp hochsensibel für Nikotin, er ist<br />
aber gleichzeitig auch von einer langen Desensitisierungsphase betroffen<br />
(Buisson, Gopalakrishnan, Arneric, Sullivan & Bertrand, 1996). Bei dem<br />
a7-Protein lässt die Desensitisierung dagegen schnell nach (Pidoplichko et<br />
al., 1997; Pidoplichko, Noguchi, Areola, Liang, Peterson, Zhang & Dani,<br />
2004), so dass er schneller erneut reagieren kann. Dieser Rezeptortyp besitzt<br />
jedoch wie bereits beschrieben eine geringere Affinität für Nikotin als die<br />
a4b2-Variante (Buisson et al., 1996). Bei allen anderen Rezeptorprotein-<br />
Mischtypen ist die Densitisierungsgeschwindigkeit auf einem Kontinuum<br />
zwischen den beiden vorgestellten Subtypen anzuordnen.<br />
41
42<br />
Neurobiologie der Nikotinabhängigkeit<br />
Abbildung 6: Aufbau des Acetylcholinrezeptors 5<br />
a4b2- und a7- Rezeptortypen werden häufig auf der gleichen Zelle ausgebildet.<br />
Man nimmt an, dass 30% der Zellen im ventralen Tegmentum, die in<br />
das dopaminerge System projizieren, beide Rezeptortypen besitzen (Pidoplichko<br />
et al., 1997). Für den raschen Kalziumeinstrom nach der Nikotinapplikation<br />
scheint der a7-Subtyp verantwortlich zu sein (Mansvelder &<br />
McGehee, 2000), da die Zellen rasch und mit geringer Affinität reagieren.<br />
Die wesentliche Verstärkerwirkung wird jedoch als durch die verzögerte<br />
Aktivierung bedingt angesehen. Bei anhaltender Nikotinzufuhr reagieren<br />
entsprechend nur noch die weniger sensitiven, sich aber rasch erholenden<br />
a7-Untereinheiten. So bleibt die Funktionsfähigkeit des cholinergen Systems<br />
gewährleistet. Vermutlich wird durch freie a7-Rezeptoren bei anhal-<br />
5 Gedruckt mit der Erlaubnis von Encyclopaedia Britannica, © 2002 by Encyclopaedia Britannica,<br />
Inc. (Encyclopaedia Britannica, 2009)
Neurobiologie der Nikotinabhängigkeit<br />
tender Nikotinzufuhr auch die Stimulation des dopaminergen Systems garantiert,<br />
obwohl die a4b2-Rezeptoren durch die Blockade und Inaktivierung<br />
die Dopaminantwort reduzieren.<br />
Auch im Striatum wurden Hinweise auf die Existenz zweier Arten von<br />
Nikotinrezeptoren auf dopaminergen Neuronen gefunden. Neben a4b2-<br />
Rezeptoren scheinen zusätzlich a3b2-Rezeptoren bei der Freisetzung von<br />
Dopamin involviert zu sein (Kaiser & Wonnacott, 2000). Möglicherweise<br />
sind hier auch noch andere Neurone beteiligt, die nicht dem dopaminergen<br />
System, sondern z.B. dem glutamatergen System angehören könnten, aber<br />
a7-Rezeptoren tragen (Mansvelder & McGehee, 2000).<br />
In vivo- und in vitro-Experimente konnten zeigen, dass bei kontinuierlicher<br />
Gabe von Nikotin in Konzentrationen, die nikotinerge Rezeptoren auf dopaminergen<br />
Neuronen im mesolimbischen System aktivieren können, eine<br />
Vermehrung der Bindungskapazität für Nikotin im Gehirn zu beobachten<br />
ist. Wonnacott, Drasdo, Sanderson und Rowell (1990) gehen davon aus,<br />
dass eine kompensatorische Vermehrung der nikotinergen Acetylcholinrezeptoren<br />
das Ergebnis des Bemühens ist, die Ausgangslage wieder herzustellen.<br />
Der Normalzustand scheint aus dem Gleichgewicht zu sein, da sich<br />
die Anzahl desensitisierter Rezeptoren durch die Bindung des Nikotins<br />
erhöht und so eine geringere Menge funktionsfähiger Andockstellen zur<br />
Verfügung stehen (Peng, Gerzanich, Anand, Whiting & Lindstrom, 1994).<br />
Dieser Prozess wird als Rezeptor-Upregulation (Breese, Marks, Logel,<br />
Adams, Sullivan, Collins & Leonard, 1997; Buisson & Bertrand, 2001)<br />
bezeichnet. Manche Autoren gehen davon aus, dass die Hochregulation<br />
durch eine erhöhte Bildung von Rezeptoren mit Hilfe des Zusammenschlusses<br />
von Subeinheiten im endoplasmatischen Retikulum (Sallette, Bohler,<br />
Benoit, Soudant, Le Novere, Changeux & Corringer, 2004), oder des vermehrten<br />
Transports von Rezeptoren an die Zelloberfläche (Harkness &<br />
Millar, 2002) erfolgt. Neuere Studien gehen jedoch von einem veränderten<br />
Rezeptorzustand aus, der auf variierenden Aktivierungs- und Desensitierungsprozessen<br />
beruht. Vallejo, Buisson, Bertrand und Green (2005) stellten<br />
die Hypothese auf, dass die betroffenen Rezeptoren nach chronischer<br />
Nikotinzufuhr langsam in einem Zustand hoher Affinität stabilisieren und in<br />
43
44<br />
Neurobiologie der Nikotinabhängigkeit<br />
der Folge sowohl eine erhöhte Bindung von Agonisten als auch eine erhöhte<br />
Antwort des Rezeptors möglich wird. Eine direkte Messung der Anzahl der<br />
Rezeptoren an der Zelloberfläche, die von der gleichen Arbeitsgruppe<br />
durchgeführt wurde, ergab keine Veränderungen durch Nikotinzufuhr und<br />
auch die Unterbrechung des Rezeptortransports an die Zelloberfläche durch<br />
Brefeldin A veränderte die Hochregulation nicht, was den Hypothesen von<br />
Harkness und Millar (2002) und Peng et al. (1994) widersprechen würde.<br />
Jedoch wurden bei der Messung der Bindungsstellen nur die aktivierten,<br />
also hochregulierten Rezeptoren gemessen, nicht die sich im Ruhezustand<br />
befindlichen. Entsprechend könnte die erhöhte Bindung des Agonisten auch<br />
auf eine Verschiebung des Gleichgewichts zwischen hochregulierten und im<br />
Ruhezustand befindlichen Rezeptoren durch Nikotinzufuhr betrachtet werden.<br />
Elektrophysiologische Messungen unterstützen diese These (Vallejo et<br />
al., 2005).<br />
Laut Watkins et al. (1999) beschränkt sich das Phänomen der Upregulation<br />
auf den Hippocampus, wo sich die Rezeptoren nahezu verdoppeln, sowie<br />
den Gyrus rectus, den Cortex des Kleinhirns und den Raphekern, in denen<br />
eine Erhöhung um circa 50% erfolgt. Breese et al. (1997) berichten bei<br />
lebenslangen Rauchern außerdem von einer erhöhten Nikotinbindung im<br />
Thalamus. Von der Upregulation sind wegen der starken und lang anhaltenden<br />
Desensitisierung vor allem a4b2-Rezeptoren betroffen. Der menschliche<br />
Organismus befindet sich unter kontinuierlicher Nikotingabe durch die<br />
sich teilweise im inaktiven Zustand befindlichen Rezeptoren nach der<br />
Upregulation in einem kompensierten Zustand. Bleibt jedoch die Zufuhr des<br />
Nikotins aus, wird das Gleichgewicht gestört, da vorher besetzte Rezeptoren<br />
wieder frei werden und vermutlich ihre natürliche Funktion wieder aufnehmen.<br />
Es kommt also zu einem Überangebot funktionsfähiger nikotinerger<br />
Acetylcholinrezeporen, das für die Entstehung der Entzugssymptomatik<br />
verantwortlich sein oder zumindest mit deren Intensität korrelieren könnte.<br />
Da die Symptome im Entzug jedoch vielgestaltig sind, können wahrscheinlich<br />
nur einige durch den Mechanismus der Upregulation erklärt werden.<br />
Dazu zählen neben affektiven Störungen und Einschränkungen der Vigilanz<br />
bzw. der Konzentrationsfähigkeit auch andere Äquivalente der kognitiven<br />
Leistungsfähigkeit. Ein Rückfall beseitigt die Entzugssymptomatik und
Neurobiologie der Nikotinabhängigkeit<br />
wird sofort über dopaminerge Stimulation, sowie durch Deaktivierung der<br />
überschüssigen nikotinergen Rezeptoren vom a4b2-Typ negativ verstärkt.<br />
Der Mechanismus der Upregulation könnte dementsprechend eine Erklärung<br />
für die Nikotinabhängigkeit darstellen. Dabei könnte der Grad der<br />
Abhängigkeit mit einer individuell unterschiedlichen Neuroadaptation zusammenhängen.<br />
3.2. Weitere beteiligte Neurotransmittersysteme<br />
Außer dem cholinergen und dem dopaminergen System wird auch von einer<br />
Reihe weiterer Neurotransmitter angenommen, dass sie Einfluss auf die<br />
Entwicklung bzw. Aufrechterhaltung einer Nikotinabhängigkeit haben. Der<br />
neben den beiden bereits dargestellten Botenstoffen als am wichtigsten<br />
angesehene und am besten erforschte ist das Serotonin. Seine Bahnen entspringen<br />
im Hirnstamm in den so genannten Raphekernen und ziehen von<br />
dort zu einer Vielzahl kortikaler und subkortikaler Regionen (Baumgarten<br />
& Grozdanovic, 1995). Durch die starke Verzweigung des Systems wird<br />
neben der Nikotinabhängigkeit auch bei vielen anderen psychischen Auffälligkeiten<br />
eine Verbindung mit hier lokalisierten Störungen angenommen<br />
(Grove, Coplan & Hollander, 1997; Meltzer, Maes & Elkis, 1994).<br />
3.2.1. Serotonin<br />
In Bezug auf die Nikotinabhängigkeit ist es von besonderer Bedeutung, dass<br />
auf den päsynaptischen Endigungen serotonerger Neuronen nikotininerge<br />
Acetylcholinrezeptoren lokalisiert sind (Benwell, Balfour & Anderson,<br />
1990). Benwell und Balfour (1979) stellten in einer Untersuchung an Ratten<br />
fest, dass sowohl nach einmaliger als auch nach wiederholter, chronischer<br />
Nikotinzufuhr die Konzentration und die Synthese von Serotonin im Bereich<br />
des Hippocampus geringer ausfällt. Dies führte die gleiche Arbeitsgruppe<br />
einige Jahre später (Benwell, Balfour & Anderson, 1988) auf die<br />
Aktivierung entsprechender Rezeptoren in den Raphekernen und im Hippocampus<br />
zurück und bestätigte diese Annahme durch die Beobachtung einer<br />
verminderten Sekretion von Serotonin im Hippocampus von Rauchern.<br />
Zusätzlich wurde eine Erhöhung der Dichte spezifischer Serotoninrezepto-<br />
45
46<br />
Neurobiologie der Nikotinabhängigkeit<br />
ren im Bereich des gesamten Hippocampus entdeckt, die als Kompensationsmechanismus<br />
für die reduzierte Aktivität serotonerger Neuronen verstanden<br />
wird und zu einer weiteren Verringerung des Botenstoffspiegels<br />
führt.<br />
Klinische Wirkungen dieses Neurotransmittersystems sind bisher noch nicht<br />
ausreichend erforscht, Spekulationen ziehen aber vor allem die subjektiv<br />
erlebten anxiolytischen und antidepressiven Effekte des Rauchens in Betracht.<br />
Eine chronische und repetitive Nikotinzufuhr könnte zu einer anhaltenden<br />
Veränderung der synaptischen serotonergen Funktionen im Hippocampus<br />
führen, die durch Ausbleiben von Nikotin, also im Entzug, aus dem<br />
Gleichgewicht gebracht werden und affektive Störungen auslösen könnten.<br />
Dies wäre auch eine mögliche Erklärung für die bei prämorbid nicht erkrankten<br />
Menschen häufig auftretenden depressiven Symptome im ersten<br />
Stadium nach dem Rauchstopp. Andererseits könnte die auffällig erhöhte<br />
Prävalenz des Rauchens bei Depressiven im Vergleich zu psychiatrisch<br />
unauffälligen Menschen auch auf eine Selbstselektion im Sinne einer<br />
„Selbstmedikation“ hindeuten (Batra, 2000). Dann wäre die Störung im<br />
serotonergen System eher eine Ursache des Rauchens. Neben all diesen<br />
Überlegungen darf außerdem nicht außer Betracht gelassen werden, dass<br />
auch andere Inhaltsstoffe im Tabakrauch eine Affektregulation bewirken<br />
könnten.<br />
3.2.2. Weitere Neurotransmitter<br />
Im Gegensatz zur Abhängigkeitsentwicklung bei den meisten anderen psychotropen<br />
Substanzen sind bei Nikotin viele sekundäre Strukturen in die<br />
neurobiologischen Prozesse mit eingebunden und gestalten sie entsprechend<br />
komplizierter. Es ist möglich, dass beim Rauchen verschiedene Transmittersysteme<br />
gegenläufig aktiviert werden. Forschungen auf diesem Gebiet sind<br />
jedoch bisher sehr selten. Bekannt ist, dass Nikotin auch die Freisetzung<br />
von Noradrenalin unter anderem im ventralen Hippocampus bewirkt. Außerdem<br />
wird eine Beteiligung afferenter glutamaterger Neuronen im<br />
präfrontalen Kortex an der dopaminergen Aktivierung angenommen (Vidal,<br />
1994). Auch hier wird präsynaptischen nikotinergen Acetylcholinrezeptoren<br />
eine entscheidende Rolle zugesprochen, da deren Aktivierung zu einer er-
Neurobiologie der Nikotinabhängigkeit<br />
höhten Glutamatausschüttung im Nucleus accumbens führen soll. Schließlich<br />
schreiben Tempel und Zukin (1987) und McGehee (2006) auch den<br />
mu-Opioid-Rezeptoren eine Bedeutung für die Wirkungsvermittlung von<br />
Nikotin zu. Nach dessen Gabe konnten sie einen Anstieg von endogenen<br />
Opioiden im Nucleus accumbens beobachten, denen wiederum eine verhaltensverstärkende<br />
Wirkung zugesprochen wird (Walters, Cleck, Kuo &<br />
Blendy, 2005).<br />
3.3. Dopaminerges Belohnungssystem<br />
Wie jede abhängig machende Substanz ruft auch Nikotin positive Wirkungen<br />
hervor, die dazu beitragen, den Konsum trotz schädlicher Nebenwirkungen<br />
aufrechtzuerhalten. In den beiden vorangegangenen Kapiteln war<br />
bereits mehrfach die Rede von der herausragenden Bedeutung dopaminerger<br />
Strukturen. Im folgenden Abschnitt soll deswegen noch einmal detailliert<br />
auf das Belohnungssystem eingegangen werden.<br />
Rosecrans, Spencer, Krynock und Chance (1978) gelang es mit Hilfe des so<br />
genannten diskriminativen Paradigmas bei Ratten, Hinweise auf die Beteiligung<br />
des dopaminergen Systems bei der Verarbeitung von Nikotin zu finden.<br />
Sie konditionierten die Tiere auf Salin, Nikotin und nikotinähnliche<br />
Substanzen, um deren diskriminative Eigenschaften untersuchen zu können.<br />
Da in dieser Untersuchung ausschließlich Nikotin von den Tieren selbst<br />
appliziert wurde und der Konsum mit einer Dopaminausschüttung im<br />
ventralen Striatum bzw. dem Nucleus accumbens einher ging, werden die<br />
subjektiv als angenehm empfundenen Wirkungen seither diesem System<br />
zugeschrieben (Imperato & Di Chiara, 1986). Im Sinne einer operanten<br />
Konditionierung wird in der Folge die Auftretenswahrscheinlichkeit von<br />
Verhaltensweisen erhöht, die zu der Dopaminausschüttung geführt haben<br />
(Wise, 1988). Diese drogeninduzierte Neurotransmittermodulation wird,<br />
wie bereits in Kapitel 3.1. beschrieben, als notwendiger und entscheidender<br />
neurobiologischer Bestandteil der Abhängigkeitsentwicklung angesehen<br />
(Heinz, 2000; Wise, 1988). Durch diesen Mechanismus tritt Nikotin direkt<br />
mit dem dopaminergen Belohnungs- bzw. Verstärkungssystem in Interaktion,<br />
das entwicklungsgeschichtlich ein sehr altes System ist und über primä-<br />
47
48<br />
Neurobiologie der Nikotinabhängigkeit<br />
re Verstärker wie Nahrungs- oder Flüssigkeitsaufnahme, sexuelle Aktivität<br />
und elterliches Fürsorgeverhalten aktiviert wird. Seine verhaltensverstärkende<br />
Wirkung wird darauf zurückgeführt, dass überlebenswichtige Reize<br />
identifiziert werden mussten und nur so das Überleben der Art gewährleistet<br />
war (Robbins & Everitt, 1999). Skinner (1935) war der erste, der sich mit<br />
dem Konzept der Verhaltensverstärkung auseinandersetzte. Er formulierte<br />
die Annahme, ein Verhalten trete dann häufiger auf, wenn es positiv verstärkt<br />
werde. Allerdings implizierte dieses ursprüngliche Postulat kein verstärktes<br />
Lustempfinden, sondern beinhaltete ausschließlich die erhöhte<br />
Auftretenswahrscheinlichkeit der Verhaltensweisen, unabhängig von tatsächlichem<br />
Lustempfinden, Verlangen oder anderen motivationalen Zuständen.<br />
Auf neurobiologischer Ebene ruft die Aktivierung des dopaminergen Belohnungssystems<br />
eine Verstärkung der Reizüberleitung und –verarbeitung<br />
hervor (Daniel, Weinberger, Jones, Zigun, Coppola, Handel, Bigelow,<br />
Goldberg, Berman & Kleinman, 1991), so dass die erhöhte Antwort auf<br />
eintreffende Reize als Zunahme der Signalübertragung in Abgrenzung zu<br />
Rauschen sichtbar wird und eine fokussierte Aktivierung spezifischer neuronaler<br />
Netze nach sich zieht. Da die Ergebnisse der folgenden Abschnitte<br />
vorwiegend aus Tierexperimenten stammen, ist eine Übertragung dieser<br />
Befunde auf den Menschen nur bedingt möglich.<br />
3.3.1. Neuroanatomie des dopaminergen Belohnungssystems<br />
Das dopaminerge Verstärkungssystem besteht aus vier Bahnsystemen, die<br />
in unterschiedliche Hirnregionen projizieren (Heinz, 2000). Die so genannte<br />
mesostriato-pallidale Bahn beinhaltet den Nucleus caudatus, das Putamen<br />
und die Kernregion des Nucleus accumbens. Das mesostriato-amygdaloide<br />
System besteht vorwiegend aus der „extended Amygdala“, die die Schalenregion<br />
des Nucleus accumbens, sowie die zentrale und laterale Amygdala<br />
umfasst. Der mesolimbische Teil beinhaltet in erster Linie dopaminerge<br />
Projektionsareale des Allokortex, während die vierte, mesocorticale Bahn<br />
dopaminerge Projektionen zum frontalen, parietalen und temporalen Isokortex<br />
unterhält. Die wichtigsten limbischen Zentren sind der Abbildung 7 zu<br />
entnehmen.
Neurobiologie der Nikotinabhängigkeit<br />
Abbildung 7:Die wichtigsten limbischen Zentren des menschlichen Gehirns 6<br />
Ergebnisse von Schultz, Apicella und Ljungberg (1993) legen die Annahme<br />
einer Interaktion zwischen den verschiedenen Teilen des Verstärkungssystems<br />
nahe. So konnten sie beobachten, dass bei Eintreffen einer unerwarteten<br />
Belohnung die Entladungsrate im dorsalen und ventralen Striatum erhöht<br />
war. Nach erfolgter Konditionierung traten jedoch keine Unterschiede<br />
mehr in der Feuerungsmenge der dopaminergen Neuronen als Folge des<br />
Eintretens der Verstärkung auf, wohl aber während der Präsentation des<br />
konditionierten Reizes. Die Autoren schlossen aus diesen Befunden in Bezug<br />
auf den Konsum abhängig machender Substanzen, dass eine dopaminerge<br />
Stimulation zum Einen zielgerichtete Handlungen einleiten könnte,<br />
die zur Beschaffung der Substanz führen und zum Anderen auch für das<br />
reizinduzierte Craving, also das Verlangen nach der Droge nach Auftreten<br />
6 aus Roth, 2009<br />
49
50<br />
Neurobiologie der Nikotinabhängigkeit<br />
eines konditionierten Stimulus, verantwortlich sein könnte. Watanabe<br />
(1996) fand außerdem heraus, dass bestimmte Neuronen nur bei Eintreffen<br />
einer erwarteten Belohnung aktiviert werden, nicht jedoch bei einer überraschenden<br />
Verstärkung. Dies weist auf eine Beteiligung des frontalen Kortex<br />
beim Erlernen belohnungsabhängiger Verhaltensweisen als zentrales Exekutivsystem<br />
hin, das Aufmerksamkeit und Informationsfluss zwischen verschiedenen<br />
Kurzzeitspeichern reguliert und so zielgerichtetes Verhalten<br />
ermöglichen soll.<br />
Die Verstärkerwirkung selbst wird mit verschiedenen Dopaminrezeptoren<br />
assoziiert. So gehen Sibley und Monsma (1992) davon aus, dass vor allem<br />
die Aktivierung von Dopamin- D1-Rezeptoren eine entscheidende Rolle im<br />
Belohnungsprozess spielt. D1-artige Rezeptoren, zu denen D1- und D5-<br />
Varianten zählen, erhöhen über die Aktivierung stimulierender G-Proteine<br />
die cAMP-Konzentration und regen so die GABAergen Neuronen des Striatums<br />
an. Chu und Kelley (1992) postulieren, dass eine konditionierte Verhaltensverstärkung<br />
nur bei gleichzeitiger Gabe von D1- und D2-Agonisten<br />
auftritt. Die Verabreichung oder Aktivierung einzelner Agonisten ist ihrer<br />
Ansicht nach nicht ausreichend. D2-artige Rezeptoren, zu denen der D2-,<br />
D3- und D4-Typ gehören, inhibieren postsynaptisch cAMP in striären GA-<br />
BAergen Neuronen und aktivieren thalamokortikale Projektionen über die<br />
Inhibition des Nucleus subthalamicus (Sibley & Monsma, 1992). Nach<br />
Gabe eines Agonisten für D3-Rezeptoren, die sich vorwiegend im ventralen<br />
Striatum befinden, konnte ein reduziertes Drogensuchverhalten bei Ratten<br />
festgestellt werden (Pilla, Perachon, Sautel, Garrido, Mann, Wermuth,<br />
Schwartz, Everitt & Sokoloff, 1999). Herz (1995) zieht deswegen die<br />
Schlussfolgerung, dass die Selbstapplikation belohnender Substanzen wahrscheinlich<br />
durch unterschiedliche Rezeptorarten vermittelt wird und eine<br />
funktionale Trennung aufgrund der gleichsinnigen Wirkungen in Folge der<br />
Drogeneinnahme und verschiedener Interaktionen innerhalb des Rezeptorsystems<br />
offenbar nicht möglich ist.
3.3.2. Kortikale Projektionsbahnen<br />
Neurobiologie der Nikotinabhängigkeit<br />
Auch verschiedene kortikale dopaminerge Projektionsbahnen interagieren<br />
mit der striären Dopaminfreisetzung und beeinflussen so die verhaltensverstärkenden<br />
Wirkungen von Substanzen. So spielt z.B. das Arbeitsgedächtnis<br />
eine zentrale Rolle beim Erlernen zeitverzögerter operanter Verhaltensweisen.<br />
Während der Verarbeitung feuern präfrontale Neuronen kontinuierlich<br />
in Abhängigkeit von der Reizlokalisation (Williams & Goldman-Rakic,<br />
1995). Zusätzlich werden belohnungsrelevante Informationen über Stimuli<br />
und die operante zeitverzögerte Handlung im präfrontalen Kortex encodiert,<br />
die wiederum die striäre Dopaminfreisetzung beeinflussen. Des Weiteren<br />
ergaben verschiedene Untersuchungen, dass die subkortikale dopaminerge<br />
Transmission von der präfrontalen Dopaminfreisetzung über die Inhibition<br />
der Ausschüttung von Dopamin im Striatum beeinflusst wird. Es wird angenommen,<br />
dass diesem Prozess eine dopaminerge Stimulation GABAerger<br />
Interneuronen im präfrontalen Kortex zugrunde liegt, welche wiederum die<br />
glutamaterge Stimulation der subkortikalen Dopaminfreisetzung inhibieren<br />
(Anderson, Christoff, Stappen, Panitz, Ghahremani, Glover, Gabrieli &<br />
Sobel, 2003; Imperato, Honoré & Jensen, 1990).<br />
3.3.3. Amygdala<br />
Als weiterer wichtiger Bestandteil des dopaminergen Belohnungssystems<br />
gilt die Amgydala, die in einem intensiven Austausch mit dem frontalen<br />
Kortex steht. Der basolaterale Teil scheint entscheidend an Lernvorgängen<br />
beteiligt zu sein und vermittelt offenbar diejenigen Effekte, die affektiv<br />
positiv besetzte Reize auf zielgerichtetes Verhalten haben. Die zentrale<br />
Amygdala steuert hingegen einfache konditionierte appetitive Reaktionen,<br />
die nicht entscheidend zur Steuerung operanten, zielgerichteten Verhaltens<br />
beitragen (Robbins & Everitt, 1999). Generell führt eine Aktivierung der<br />
Amygdala zu einer erhöhten glutamatergen Stimulation des präfrontalen<br />
Kortex und der Shell-Region des Nucleus accumbens. Eine gleichzeitige<br />
striäre Dopaminausschüttung scheint dagegen durch eine hemmende Projektion<br />
des präfrontalen Kortex unterdrückt zu werden (s.o.). Jackobson und<br />
Moghaddam (2001) konnten beobachten, dass bei Hemmung der glutamatergen<br />
Aktivierung des präfrontalen Kortex die subkortikale Dopaminfrei-<br />
51
52<br />
Neurobiologie der Nikotinabhängigkeit<br />
setzung nach Amygdalastimulation anstieg und zur Perseveration der durch<br />
die Amygdala ausgelösten Verhaltensweisen führte. Entsprechend kann<br />
man die Schlussfolgerung ziehen, dass die Aktivierung der basolateralen<br />
Amygdala eine dopaminerg vermittelte Verhaltensaktivierung auslöst, die<br />
bei intaktem Frontalhirn gehemmt wird. Treten Schädigungen der frontalen<br />
Kontrolle auf, ist offenbar eine Manifestation stereotyper Verhaltensweisen<br />
durch konditionierte Reize möglich. Die verstärkte striäre Dopaminfreisetzung<br />
könnte im Fall von Drogenkonsum im ventralen Striatum eine erhöhte<br />
Motivation zur weiteren Substanzeinnahme hervorrufen und im dorsalen<br />
Striatum die stereotypen drogenassoziierten Verhaltensweisen manifestieren.<br />
Auch der Hippocampus, der eine zentrale Rolle bei Gedächtnisprozessen<br />
spielt, steuert die striäre Dopaminfreisetzung und könnte entsprechend<br />
ein neurobiologisches Äquivalent des so genannten Suchtgedächtnisses<br />
darstellen.<br />
Zusammenfassend kann festgehalten werden, dass die durch konditionierte<br />
Reize ausgelöste und dopaminerg vermittelte Motivation zur Drogeneinnahme<br />
wahrscheinlich der vorherigen kortikalen Reizanalyse im frontalen<br />
Kortex und der Amygdala, sowie des Abgleichs mit Gedächtnisspuren im<br />
Hippocampus bedarf (Robbins & Everitt, 1999). Dabei scheint die kortikale<br />
Reizanalyse im Wesentlichen glutamaterg vermittelt zu sein und kann über<br />
glutamaterge Projektionsbahnen zum ventralen Tegmentum (VTA) eine<br />
Dopaminfreisetzung im ventralen Striatum auslösen. Das dopaminerge<br />
Belohungssystem wird also wahrscheinlich nur in Interaktion mit kortikalen<br />
und subkortikalen Zentren aktiviert.<br />
3.3.4. Dopaminerges System: Wanting oder liking?<br />
Grundsätzlich scheint das dopaminerge Verstärkungssystem Umweltreize<br />
als potentiell belohnend zu kodieren, dennoch ist es aber wahrscheinlich<br />
nicht selbst Träger der Lustempfindung nach Eintreffen der Belohnung.<br />
Man geht davon aus, dass das System zwar ein Verlangen nach der Substanz<br />
bewirkt, aber keinen Genuss („wanting, not liking“) (Berridge & Robinson,<br />
1998) zu vermitteln vermag. Die Trennung dieser beiden Phänomene<br />
ist in der Regel schwer zu vollziehen, da Lustempfinden und Verhaltensverstärkung<br />
meist gleichzeitig auftreten. Durch die spezifische selektive
Neurobiologie der Nikotinabhängigkeit<br />
Stimulierung der dopaminergen Neurotransmission können Drogen jedoch<br />
auch dann noch Craving auslösen, wenn sie längst keine angenehmen Wirkungen<br />
mehr hervorrufen. Eine Bestätigung für diese Annahme lieferten<br />
Berridge und Robinson (1998), die nach einer weitgehenden Zerstörung der<br />
dopaminergen Bahnsysteme bei Ratten eine anhaltende hedonische Reaktion<br />
auslösen konnten, wenn sie eine Zuckerlösung verabreichten, während<br />
gleichzeitig die Motivation zum selbst initiierten Konsum quasi nicht mehr<br />
beobachtbar war. Die gleichen Autoren berichten in ihrem Überblick davon,<br />
dass die Dopaminausschüttung in mehreren Untersuchungen bei den Versuchstieren<br />
bereits vor dem Konsum der belohnenden Substanz maximal<br />
war. Würde Dopamin für das ´liking´ verantwortlich sein, müsste das Maximum<br />
jedoch während des tatsächlichen Kontakts mit dem Verstärker<br />
eintreten. Ein weiterer Beleg für diese Hypothese findet sich auch im klinischen<br />
Alltag bei psychiatrischen Patienten, die unter einer verminderten<br />
Empfindlichkeit zentraler Dopamin-D2-Rezeptoren leiden. Bei ihnen finden<br />
sich eine Motivationsstörung und eine affektive Verflachung, jedoch keine<br />
Symptome von Anhedonie (Schmidt, Nolte-Zenker, Patzer, Bauer, Schmidt,<br />
Rommelspacher & Heinz, 2001). Mit der hedonischen Einschätzung des<br />
Verstärkers werden hingegen andere neurale Substrate wie das GA-<br />
BA/Benzodiazepin-System im Hirnstamm, ventrale pallidale Systeme oder<br />
opioide Systeme im Shell des Nucleus accumbens in Verbindung gebracht,<br />
da Manipulationen dieser Areale die Evaluation von Reizen verändern können<br />
(Berridge & Robinson, 1998).<br />
3.3.5. Nucleus accumbens und ventrales Tegmentum<br />
Ein zentraler Bestandteil des mesolombischen dopaminergen Systems ist,<br />
wie bereits mehrfach in den vorangegangenen Abschnitten erwähnt, das<br />
ventrale Striatum. Es besteht aus der Kern- und der Schalenregion des Nucleus<br />
accumbens, der als Sitz des Selbstbelohnungs- und Selbstverstärkungszentrums<br />
gilt. Diese Region ist bei der Administration von Nikotin und für<br />
das Signalisieren der Anwesenheit drogenassoziierter Umweltreize besonders<br />
wichtig, da sie eine zweifache Funktion in der Informationsverarbeitung<br />
hedonischer Effekte besitzt. Dopaminerge Projektionen zur Schalenregion<br />
zeigen die Anwesenheit belohnender Stimuli an und erleichtern so das<br />
53
54<br />
Neurobiologie der Nikotinabhängigkeit<br />
Erlernen neuer Verhaltensweisen, die mit dem Erhalt der Verstärkung verbunden<br />
waren (Benwell & Balfour, 1997; Besson, Granon, Mameli-Engvall,<br />
Cloez-Tayarani, Mauourguet, Cormier, Cazala, David, Changeux & Faure,<br />
2007). Nach Balfour, Wright, Benwell und Birelli (2000) findet hier die<br />
zentrale Vermittlung der verhaltensverstärkenden Effekte des Nikotins statt.<br />
Aus Tierexperimenten ist bekannt, dass die Injektion von Nikotin einen<br />
Anstieg des Dopamins im extrazellulären Raum des Nucleus accumbens<br />
bewirkt (Benwell & Balfour, 1997; Nisell, Monikos & Svensson, 1997;<br />
Pontieri, Tanda, Orzi & Di Chiara, 1996). Dabei liegt der Grad der Erhöhung<br />
über der in Folge der Verabreichung von Morphin, Methadon oder<br />
Alkohol beobachteten, jedoch niedriger als nach der Gabe von Amphetaminen<br />
oder Kokain (Imperato et al., 1990; Iversen, 1996; Pontieri et al., 1996).<br />
Als weitere Untermauerung der entscheidenden Rolle des Nucleus accumbens<br />
in der Verarbeitung von Nikotin wird die um 25% verminderte Dopaminausschüttung<br />
in diesem Gehirnareal im Entzug angeführt (Nomikos,<br />
Hildebrand, Panagis & Svensson, 1999).<br />
Wie bereits erwähnt, wird auch den nikotinischen Acetylcholinrezeptoren,<br />
die auf Dopaminrezeptoren im ventralen Tegmentum lokalisiert sind, eine<br />
wichtige Rolle für die Nikotinwirkung zugeschrieben (Laviolette & van der<br />
Kooy, 2004; Mansvelder et al., 2003). Nach Ansicht der Autoren aktiviert<br />
Nikotin, wenn es das ventrale Tegmentum erreicht, die dort auf den Dopaminneuronen<br />
angesiedelten hochaffinen nikotinischen Acetylcholinrezeptoren.<br />
Diese desensitisieren innerhalb weniger Sekunden bereits bei geringen<br />
Konzentrationen (Pidoplichko et al., 1997) und können entsprechend nicht<br />
für den langanhaltenden Dopaminanstieg im Nucleus accumbens verantwortlich<br />
sein. Deswegen postulieren Laviolette und van der Kooy (2004)<br />
zwei synaptische Mechanismen, die für die anhaltenden stimulierenden<br />
Effekte auf die Dopaminneuronen des ventralen Tegmentums verantwortlich<br />
sein könnten. Dazu zählt zum einen die nikotininduzierte Langzeitpotenzierung<br />
des exzitatorischen glutamatergen Inputs, an der nikotinische<br />
Acetylcholinrezeptoren stark beteiligt sind (s. Kap. 3.5.).<br />
Zum anderen führen die Autoren die nikotininduzierte Depression von Rezeptoren<br />
als entscheidenden Vorgang nach der Nikotinexposition an, die
Neurobiologie der Nikotinabhängigkeit<br />
Folge einer GABAergen Modulation innerhalb des ventralen Tegmentums<br />
ist. Die inhibitorische Kontrolle geht während dieses Prozesses vorwiegend<br />
von GABAergen Interneuronen im ventralen Tegmentum und von projizierenden<br />
GABA-Fasern von anderen Gehirnarealen inklusive des Nucleus<br />
accumbens aus (Laviolette & van der Kooy, 2004). Die Aktivierung erstgenannter<br />
durch exogenes Nikotin führt zu einem Anstieg ihrer Feuerungsrate,<br />
also einer stärker ausgeprägten Hemmung der Zielregionen (Mansvelder,<br />
Keath & McGehee, 2002), und könnte einen Teil des exzitatorischen Inputs<br />
in den ersten Phasen der Nikotinzufuhr außer Gefecht setzen. Da diese nikotinischen<br />
Acetylcholinrezeptoren jedoch vom hochaffinen Typ sind, tritt<br />
eine rasche Desensitisierung innerhalb weniger Minuten ein und es folgt<br />
eine deutliche Abschwächung des anfänglichen, eben geschilderten inhibitorischen<br />
Effekts auf die Dopaminneuronen. Die Mehrheit der cholinergen<br />
Inputs in das ventrale Tegmentum scheint außerdem eher die GABA-<br />
Neuronen zu kontaktieren als die dopaminergen Nervenzellen. Da Nikotin<br />
nicht von der endogenen Acetylcholinesterase gespalten wird, die Rezeptoren<br />
also somit blockiert, und die Acetylcholinrezeptoren, die in diesen Vorgang<br />
involviert sind, vom hochaffinen, schnell desensitisierenden Typ sind,<br />
wird wahrscheinlich jede weitere endogene cholinerge Regulation des synaptischen<br />
Kreislaufs eingeschränkt (Mansvelder et al., 2002). Anfänglich<br />
scheint also zuerst der GABA-Output vom Nucleus accumbens reduziert zu<br />
werden. Wenn das Nikotin den Nucleus accumbens erreicht, wird der eben<br />
geschilderte Prozess, die so genannte Feedforward-Inhibition, erleichtert,<br />
während der exzitatorische Übertragungsweg weitgehend unbehelligt bleibt.<br />
Die endogene cholinerge Modulation könnte also eine Verschiebung der<br />
Balance zwischen GABAerger und glutamaterger synaptischer Transmission<br />
hervorrufen und Veränderungen der Wahrnehmung von belohnenden<br />
Wirkungen nach sich ziehen (Laviolette & van der Kooy, 2004). Auch<br />
wenn andere Drogen den Dopaminmetabolismus und dessen Wiederaufnahme<br />
verändern, um den Dopaminlevel zu erhöhen (Mansvelder & McGehee,<br />
2002), scheint Nikotin also in erster Linie die Aktivität der Neuronen<br />
im ventralen Tegmentum zu verändern, um den Dopaminanstieg zu initiieren.<br />
Die Balance zwischen dem GABAergen und dem glutamatergen System<br />
könnte entsprechend die individuelle Vulnerabilität für die abhängig<br />
machenden Eigenschaften von Nikotin durch die Bestimmung der relativen<br />
55
56<br />
Neurobiologie der Nikotinabhängigkeit<br />
Sensitivität für die verstärkenden oder aversiven psychologischen Nikotineffekte<br />
bestimmen (Mansvelder & McGehee, 2002).<br />
Eine chronische Nikotinzufuhr verändert nach obigen Ausführungen mittel-<br />
und langfristig wahrscheinlich die Schwelle, an der eine positive Verstärkung<br />
im dopaminergen System erfolgt. Nach einer längeren Abstinenzzeit<br />
kann dann eine erneute Zufuhr verhaltensverstärkend wirken, was von starken<br />
Rauchern tatsächlich auch jeden Morgen so beschrieben wird. Diese<br />
positive Verstärkung festigt langfristig das Rauchen und erschwert mit<br />
jedem Eintreten eine Verhaltensänderung.<br />
3.4. Konditionierungsmechanismen und Störungen der<br />
Verhaltenssteuerung<br />
3.4.1. Konditionierungsmechanismen<br />
In Kapitel 3.2. war bereits die Rede von indirekten verhaltensverstärkenden<br />
Wirkungen des Nikotins durch die Freisetzung von endogenen Opioiden.<br />
Generell kann für alle Drogen festgehalten werden, dass ohne die Auslösung<br />
einer oder mehrerer angenehmer Effekte im Zentralnervensystem kein<br />
Abhängigkeitspotential für diese Substanz existiert. Lösen zwei verschiedene<br />
Drogen ähnlich angenehme Reaktionen aus, so ähneln sich meist auch<br />
die zugrunde liegenden neurobiologischen Prozesse. Beispielsweise findet<br />
sowohl bei Nikotin als auch bei Amphetaminen eine Dopaminausschüttung<br />
statt, die in bestimmten Hirnregionen wie dem ventralen Striatum angenehme<br />
Gefühle auslöst und damit die Wahrscheinlichkeit erneuten Konsums<br />
erhöht (Di Chiara, 1995; Wise, 1988). Je häufiger die Substanz eingenommen<br />
wird, desto mehr Umweltreize werden in einem Prozess der klassischen<br />
Konditionierung assoziiert, so dass auch das Auftreten dieser Stimuli<br />
bereits als diskriminativer Hinweisreiz für die Wirkungen der Droge aktiv<br />
werden und die Motivation zum Konsum auslösen kann (Glautier, 2004) (s.<br />
Kap. 3.3.4.). In einer Untersuchung von Wikler (1980) erhielten Ratten nur<br />
in einer bestimmten Box Opiate und entwickelten nach Aussetzen der Substanzgabe<br />
auch ausschließlich dort Entzugserscheinungen, zeigten also eine<br />
konditionierte Reaktion. Diese erhöhte gleichzeitig das Rückfallrisiko in
Neurobiologie der Nikotinabhängigkeit<br />
konditionierten Situationen. Durch die dort auftretenden Entzugserscheinungen<br />
erfolgte dann bei Einnahme der Substanz eine negative Verstärkung<br />
durch Reduktion der aversiven Empfindungen und der Wiedereintritt in den<br />
Suchtkreislauf. Perkins, Gerlach, Vender, Grobe, Meeker und Hutchinson<br />
(2001) stellten zudem bei Rauchern beiderlei Geschlechts fest, dass das<br />
Rauchen durch eine Blockade olfaktorischer und gustatorischer Anteile als<br />
weniger angenehm wahrgenommen wurde. Dies deutet auf eine wichtige<br />
Rolle von Geruchs- und Geschmacksreizen beim Rauchen und offenbar<br />
daran beteiligte Konditionierungsprozesse zwischen diesen Sinnesempfindungen<br />
und Nikotin hin. Wäre dies nicht der Fall, sollten sich die subjektiv<br />
wahrgenommenen Wirkungen des Nikotins auch bei Blockade der Sinnesorgane<br />
nicht verändern.<br />
3.4.2. Störungen der Verhaltenssteuerung<br />
Häufig wurde, wie bereits im vorangegangenen Kapitel beschrieben, eine<br />
Dopaminausschüttung im ventralen Striatum für die konditionierten Reaktionen<br />
auf assoziierte Reize verantwortlich gemacht (Di Chiara, 1995; Wise,<br />
1988). Robinson und Berridge (1993) postulierten jedoch, dass diese Veränderung<br />
der Neurotransmitterkonzentration nicht mit Lust oder Glücksgefühlen<br />
verbunden sei, sondern stattdessen direkt mit dem Verlangen nach<br />
der Suchtsubstanz (s. Kap. 3.3.4.). Diese These würde auch erklären, warum<br />
nach Abklingen der angenehmen Wirkungen trotzdem weiter konsumiert<br />
wird. Viele Abhängige stehen der Droge meist sehr ambivalent gegenüber,<br />
wollen reduzieren oder sogar aufhören (Robbins & Everitt, 1999). Dennoch<br />
findet der Konsum häufig weiterhin statt, da die bewusste Entscheidung<br />
gegen die Applikation von der Motivation zur Einnahme „überrannt“ wird.<br />
Bei bereits seit längerer Zeit abhängigen Patienten treten tatsächlich oft<br />
auch keine angenehmen Wirkungen mehr auf, dennoch berichten sie von<br />
obsessiven Gedanken an den Drogenkonsum (Antonuccio & Boutilier,<br />
2000). Als neurobiologische Grundlage dieser aufdringlichen Kognitionen<br />
werden Aktivierungen des orbitofrontalen Kortex und des Caudatuskopfes<br />
beobachtet (Brody, Mandelkern, London, Childress, Lee, Bota, Ho, Saxena,<br />
Baxter, Madsen & Jarvik, 2002). Dies entspricht den Strukturen, die bei<br />
Zwangserkrankungen aktiv sein sollen (Volkow & Fowler, 2000). Brody et<br />
57
58<br />
Neurobiologie der Nikotinabhängigkeit<br />
al. (2002) und Heinz (1999) gehen davon aus, dass die Aktivierung der<br />
Basalganglien zu einer Ingangsetzung von Handlungsschablonen führt, die<br />
vom orbitofrontalen Kortex aufgrund einer Fehlfunktion desselben als unzureichend<br />
bewertet wird und deshalb einen erneuten Durchlauf des orbitofrontal-striären-thalamischen<br />
Regelkreises im Sinne eines Teufelskreises<br />
nach sich zieht. Es folgt die Enthemmung dieses Systems, das mit stereotypem<br />
Verhalten und Drogenverlangen assoziiert wird (s. a. Kap. 3.3.3.).<br />
Parallel scheinen die emotionale und rationale Verhaltenskontrolle durch<br />
die unspezifische Schädigung des orbitofrontalen und dorsolateralen<br />
präfrontalen Kortex beeinträchtigt zu sein (Bechara, Damasio, Tranel &<br />
Anderson, 1998).<br />
Als weitere Faktoren für die Entstehung einer Abhängigkeitsentwicklung<br />
werden eine Schwäche oder eine Störung der Verhaltensplanung und –<br />
kontrolle und somit auch die Beeinträchtigung der Bewertung langfristiger<br />
Ziele (Breier, Stritzke & Lang, 1999) angeführt. Diese Funktionen werden<br />
traditionell dem frontalen Kortex zugeschrieben, insbesondere der Haubenregion<br />
(= dorsolateraler präfrontaler Kortex) (Bechara et al., 1998; dïEsposito,<br />
Detre, Alsop, Shin, Atlas & Grossmann, 1995). Auch dem anterioren<br />
Cingulum wird eine entscheidende Rolle bei der Verhaltenssteuerung zuerkannt.<br />
Insbesondere bei Konflikten zwischen zwei konkurrierenden Handlungsalternativen<br />
konnte eine Aktivierung dieser Region beobachtet werden<br />
(Carter, Braver, Barch, Botvinick, Noll & Cohen, 1998). Möglicherweise<br />
sind Störungen dieser beschriebenen Regionen bereits an der Entstehung<br />
der Abhängigkeit beteiligt. Im frontalen Kortex können Schädigungen nach<br />
dem Auftreten von Krankheiten oder Verletzungen auftreten, z.B. nach<br />
alkoholbedingter Schädigung des Fetus im Mutterleib, nach Hirntraumen<br />
bei körperlichem Missbrauch, im Rahmen einer Disposition zu Aufmerksamkeitsstörungen<br />
oder auch bei dem so genannten Hyperkinetischen Syndrom<br />
(Giancola & Moss, 1998). Die resultierende Störung der langfristigen<br />
Handlungskontrolle könnte dann leichter zu Rückfällen führen.
Neurobiologie der Nikotinabhängigkeit<br />
3.5. Mechanismus der Long Term Potentiation<br />
In Kapitel 3.4. war im letzten Abschnitt bereits die Rede von glutamatergen<br />
und GABAergen Neuronen und ihrer Rolle bei der Vermittlung der Nikotinwirkung<br />
im Gehirn. Der zugrunde liegende Prozess wird in der Fachliteratur<br />
als Long Term Potentiation bei klassischer Konditionierung bezeichnet<br />
(Konorski, 1948) und umschreibt die Beeinflussung der Stärke neuronaler<br />
Verbindungen durch neu eintreffende Informationen, die überdauernde<br />
Veränderungen in den Erregungsmustern der neuronalen Netze auslösen<br />
können. Verschiedene Nervenzellen stehen über Schnittstellen, die so genannten<br />
Synapsen, miteinander in Verbindung und kommunizieren mit<br />
Hilfe der in den vorangegangenen Kapiteln beschriebenen Neurotransmitter.<br />
Synaptische Verbindungen zwischen zwei Neuronen werden dann verstärkt,<br />
wenn diese beiden gleichzeitig aktiv sind. Dieser Prozess wurde erstmalig<br />
im Bereich des Hippocampus bestätigt. Bliss und Collingridge (1993) konnten<br />
beobachten, dass eine hochfrequente Stimulation exzitatorischer Bahnen,<br />
die in diese Hirnregion projizieren, eine akut auftretende und langfristig<br />
anhaltende Verstärkung der neuronalen Schaltstellen hervorruft. Wenn<br />
diese Stimulation mehrere Stunden anhält, bezeichnet man diesen Mechanismus<br />
als Long Term Potentiation, der neben dem Hippocampus (Yamazaki,<br />
Fujii, Jia & Sumikawa, 2006) inzwischen auch im Neocortex entdeckt<br />
wurde (Bear & Kirkwood, 1993).<br />
Wie bereits erwähnt, sind an der Langzeitpotenzierung verschiedene Neurotransmittersysteme<br />
beteiligt, zu denen auch die NMDA-Rezeptoren gehören.<br />
Ihr Ionenkanal wird normalerweise durch Magnesiumatome blockiert,<br />
die nur dann Ein- und Ausströme in die Zelle ermöglichen, wenn Glutamat<br />
an die Zelle bindet und die Membran des Neurons gleichzeitig ausreichend<br />
durch Signale an AMPA-Rezeptoren depolarisiert wurde (Bliss & Collingridge,<br />
1993). Eine Öffnung des NMDA-Rezeptors erfordert demnach<br />
eine komplexe Interaktion verschiedener, gleichzeitig aktiver afferenter<br />
Fasersysteme. Nach Freigabe des Rezeptors durch die Magnesiumatome<br />
erfolgt ein Kalziumioneneinstrom in die Zelle, der zur Aktivierung einer<br />
Vielzahl weiterer Signaltransduktionsmechanismen führt (Bliss & Collingridge,<br />
1993).<br />
59
60<br />
Neurobiologie der Nikotinabhängigkeit<br />
Neben den eben beschriebenen postsynaptischen Systemen sind auch präsynaptische<br />
Anteile der glutamatergen Neurotransmission an der Long Term<br />
Potentiation beteiligt. Der postsynaptische, NMDA-vermittelte Kalziumeinstrom<br />
führt zur Aktivierung der Nitric Oxid Synthase (NOS) und damit zu<br />
einer vermehrten NO-Synthese. NO wirkt in diesem Prozess offenbar als<br />
retrograder Neurotransmitter, der von der Postsynapse ausgeschieden wird<br />
und auf die Erregbarkeit der Präsynapse zurück wirkt. Weitere potenziell<br />
retrograd wirkende Substanzen sind Kalium und die Arachidonsäure. Die<br />
Freisetzung der Arachidonsäure wird dabei über einen weiteren, so genannten<br />
metabotropen Glutamatrezeptor gesteuert, dessen Aktivierungsniveau<br />
scheinbar wiederum über den NMDA-gesteuerten Kalziumeinstrom reguliert<br />
wird (Bliss & Collingridge, 1993). Der auf den glutamatergen präsynaptischen<br />
Schnittstellen lokalisierte vorherrschende a7-Subtyp des nikotinischen<br />
Acetylcholinrezeptors wird durch die beim Rauchen aufgenommene<br />
Menge von Nikotin außerdem nicht signifikant desensitisiert, so dass es<br />
bei Substanzaufnahme zu einer dauerhaften Steigerung der afferenten glutamatergen<br />
Reizung der Dopaminneuronen kommt, was einen Anstieg der<br />
Dopaminkonzentration nach sich zieht (Pidoplichko et al., 2004).<br />
Für die Ingangsetzung der Long Term Potentiation reichen bereits geringe<br />
Nikotinkonzentrationen von kurzer Dauer aus (Fuji, Ji, Morita & Sumikawa,<br />
1999). Wahrscheinlich werden die beschriebenen synaptischen Veränderungen<br />
bereits nach dem Rauchen einer einzigen Zigarette ausgelöst. Die<br />
nikotininduzierte langanhaltende Potenzierung der glutamatergen Exzitation<br />
der Dopaminneuronen ist der synaptischen Plastizität ähnlich, von der man<br />
ausgeht, dass sie Lern- und Gedächtnisprozessen zugrunde liegt (Mansvelder<br />
& McGehee, 2000).<br />
Zusammenfassend reflektiert der postsynaptische Aktivierungszustand nach<br />
dem Prozess der Long Term Potentiation zum gleichen Zeitpunkt aktive<br />
Erregungsniveaus in verschiedenen Regionen. So kann die zeitliche Assoziation<br />
verschiedener Reizmuster abgebildet werden. Alle nachfolgenden<br />
Signaltransduktionsmechanismen erhöhen dann langfristig die Signalüberleitung<br />
an dieser Synapse. Der Prozess der Long Term Potentiation kann
Neurobiologie der Nikotinabhängigkeit<br />
entsprechend als das neurobiologische Korrelat langfristiger Gedächtnisprozesse<br />
betrachtet werden.<br />
3.6. Psychopharmakologische Wirkungen des Nikotins<br />
Im letzten Kapitel wurde die Verbindung zwischen den Wirkungen von<br />
Nikotin und dem Hippocampus als wichtiger Instanz von Gedächtnisprozessen<br />
im Rahmen der Long Term Potentiation bereits deutlich. Auch in Kapitel<br />
3.4. wurde bereits auf die angenehmen Wirkungen von Drogen im Allgemeinen<br />
hingewiesen, denen durch Konditionierungsprozesse ein entscheidender<br />
Beitrag an der Ausbildung von Abhängigkeit zugeschrieben<br />
wird (Miyata, 2001). Im folgenden Kapitel soll nun darauf eingegangen<br />
werden, welche angenehmen Effekte Nikotin beim Menschen auslöst. Mit<br />
der Identikation aufrechterhaltender Bedingungen durch positive Wirkungen<br />
erfüllt Nikotin das wichtigste Kriterium einer abhängig machenden<br />
Substanz.<br />
3.6.1. Aktivierung oder Sedierung?<br />
Viele Raucher berichten im Anschluss an eine gerauchte Zigarette subjektiv<br />
sowohl von entspannenden als auch von aktivierenden Effekten. Lange Zeit<br />
galten diese Berichte als inkonsistent, vor allem angesichts der Tatsache,<br />
dass ein und dieselbe Person in verschiedenen Situationen von unterschiedlich<br />
empfundenen Wirkungen berichtete. Im Laufe der letzten Jahrzehnte<br />
gelang es verschiedenen Arbeitsgruppen ein unter Drogen typisches bivalentes<br />
Wirkungsspektrum auch für Nikotin zu identifizieren (s. Grobe &<br />
Perkins, 2000). Abhängig von der Dosis kommt es entweder zur Steigerung<br />
oder zur Dämpfung des Antriebs und der Aktivität. Wird Nikotin im Bolus<br />
(griech. = „Wurf“, „Schuss“) aufgenommen, kommt es zu antriebssteigernden<br />
Effekten. Wird es dagegen in niedrigen Dosierungen appliziert, kommt<br />
es zu einer Aktivierung des sympathischen Systems (Benowitz, 1988). Außerdem<br />
wird die lokomotorische Aktivität gesteigert (Balfour, 2002; Le<br />
Foll, Diaz & Sokoloff, 2003; Reavill, Waters, Stolerman & Garcha, 1990),<br />
so dass die Stimulation als angenehm und in Folge als wiederholens- und<br />
erstrebenswert erachtet wird. Nach Warburton (1985) führen niedrige Ap-<br />
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Neurobiologie der Nikotinabhängigkeit<br />
plikationsdosen zu einer cholinergen-katecholaminergen Aktivierung. Höhere<br />
Dosierungen würden dagegen eine cholinerge Blockade und eine nachfolgende<br />
b-Endorphin-Freisetzung bewirken, die beruhigende, entspannende<br />
und sedierende Effekte auslöst (Benowitz, 1996). Comer, Binnie, Lewis,<br />
Lloyd, Oldman und Thornton (1979) und Rémond, Martinerie und Baillon<br />
(1979) gelang es, im EEG im Bereich der Alpha- und Beta-Wellen Korrelate<br />
für die biphasische Wirkung des Rauchens zu finden. Auch Dunn (1978)<br />
und Ashton, Millman, Rawlins, Telford und Thompson (1978) stellten fest,<br />
dass kleine Dosen von Nikotin die kontingente negative Variation (CNV),<br />
welche die messbare Reaktion des Versuchstieres oder der Versuchsperson<br />
zwischen einem Aufmerksamkeit erregenden Signal („auf die Plätze“) und<br />
dem Handlungsbefehl („los“) widerspiegelt, steigern. Große Dosen führten<br />
dagegen zu einer Absenkung des CNV-Signals.<br />
3.6.2. Leistungsfähigkeit<br />
Eng mit der Aktivierung verbunden ist auch die Wirkung des Nikotins auf<br />
die kognitive Leistungsfähigkeit. Levin, Wilson, Rose und McEvoy (1996)<br />
konnten in verschiedenen Untersuchungen positive Effekte auf unterschiedliche<br />
kognitive Leistungen feststellen. Es wurden Kennzeichen einer gesteigerten<br />
Vigilanz und einer verbesserten selektiven Aufmerksamkeit entdeckt<br />
(Levin, Conners, Silva, Hinton, March & Rose, 1998; Warburton, 1985).<br />
Weitere beobachtbare Effekte lagen in der Steigerung der Merk- und Lernfähigkeit,<br />
sowie der Reaktionssicherheit (Levin et al., 1998; Levin et al.,<br />
1996; Zarrindast, Sadegh & Shafaaghi, 1996). Die Informationsverarbeitungsgeschwindigkeit<br />
scheint durch Nikotin gesteigert, die Reaktionszeit<br />
verringert zu sein (Palmer, Buckley & Faulds, 1992). Die meisten Effekte<br />
beruhen wahrscheinlich auf der Fähigkeit von Nikotin, die Acetylcholinauschüttung<br />
im Gehirn zu stimulieren (Balfour & Fagerstrom, 1996). Diese<br />
Ergebnisse weckten erste Hoffnungen, Nikotin als Therapeutikum bei Morbus<br />
Alzheimer einsetzen zu können (s. Kap. 3.11.).
Neurobiologie der Nikotinabhängigkeit<br />
3.6.3. Andere psychophysiologische Wirkungen des Nikotins<br />
Köhler (2000) berichtet zusätzlich von einer antiaggressiven Wirkung und<br />
einer Euphorisierung in Folge von Nikotinkonsum. Letztere führt er auf die<br />
Anregung der dopaminergen mesolimbischen Bahnen durch die Besetzung<br />
von Acetylcholinrezeptoren im Mesencephalon, die folgende erhöhte Dopaminausschüttung<br />
in den Nucleus accumbens durch die Hemmung von<br />
MAO-B und schlussendlich die Wirkung auf das endogene Opioidsystem<br />
zurück. Zusätzlich wird von einer Angst reduzierenden (McClernon & Gilbert,<br />
2004) und einer antinozizeptiven Wirkung des Nikotins ausgegangen,<br />
die in der Stärke der des Morphins vergleichbar sein soll (Aceto, Awaya,<br />
Martin & May, 1983). Diese zeigte sich in einer Untersuchung von Jamner,<br />
Girdler, Shapiro und Jarvik (1998) jedoch nur bei Männern.<br />
3.7. Nebenwirkungen des Nikotins<br />
Neben den beschriebenen angenehmen Wirkungen löst Nikotin sowohl<br />
lang- als auch kurzfristig eine Reihe unangenehmer Begleiterscheinungen<br />
aus. Die gesundheitlichen Konsequenzen des Nikotinkonsums werden inzwischen<br />
als genauso gravierend eingeschätzt wie die so genannter harter<br />
Drogen wie Kokain oder Heroin. Viele dieser Schädigungen sind jedoch<br />
nicht auf Nikotin selbst zurückzuführen, sondern auf die ca. 4000 anderen<br />
festen und gasförmigen Inhaltsstoffe des Tabakrauchs (s. Kap. 2.4.). Da<br />
jedoch diese anderen Bestandteile bis heute für die Forschung schwer zu<br />
untersuchen sind, können noch keine genauen Aussagen über ihre spezifischen<br />
Wirkmechanismen getroffen werden.<br />
Während des Rauchens wird beim Verbrennen des Tabakblatts Nikotin mit<br />
dem Tabakrauch freigesetzt. Die arterielle Aufsättigung des Bluts durch<br />
Nikotin bewirkt, dass 25% des inhalierten Suchtstoffs innerhalb von sieben<br />
bis zehn Sekunden das Gehirn erreichen. Die Wirkungen setzen unmittelbar<br />
nach Erreichen des Zentralnervensystems ein und hängen mit der dosisabhängigen<br />
Zunahme zerebraler Glukoseassimilation zusammen (Pomerleau,<br />
1992). Dazu zählen Vasokonstriktion, die Zunahme der Herzfrequenz,<br />
Blutdruckanstieg, Abnahme des Hautwiderstands und Absinken der Haut-<br />
63
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Neurobiologie der Nikotinabhängigkeit<br />
temperatur. Außerdem wird die Gerinnungsfähigkeit des Blutes durch die<br />
verstärkte Thrombozytenaggregation und die Erhöhung des Fibrinogenspiegels<br />
erhöht (Köhler, 2000).<br />
Erste aversiv erlebte Begleiterscheinungen des Tabakrauchs wie Schwindel<br />
und leichte Übelkeit, die ein naiver Raucher noch empfindet und die durch<br />
Inhaltsstoffe wie Kohlenmonoxid vermittelt werden, werden im Zuge einer<br />
Toleranzentwicklung nicht oder nur noch unterschwellig wahrgenommen<br />
(Fattinger, Verotta & Benowitz, 1997). Auch die schnell eintretenden deutlichen<br />
Einbußen im Schmecken und Riechen kommen dem Raucher entgegen,<br />
da er so den unangenehmen Geruch und Geschmack der Zigarette nicht<br />
mehr bewusst wahrnimmt. Außerdem passt sich das periphere Herz-<br />
Kreislauf-System an die Nikotinzufuhr an. Meist erfolgt eine Dosissteigerung<br />
durch Erhöhung der konsumierten Menge, bis das individuelle Optimum<br />
erreicht ist. Dieses wird meist über Jahre oder sogar Jahrzehnte hinweg<br />
beibehalten und liegt für die Mehrzahl der Raucher zwischen 15 und 30<br />
Zigaretten pro Tag.<br />
Häufig entwickeln sich bereits wenige Stunden nach dem letzten Konsum<br />
erste Entzugserscheinungen, die sich in Rauchverlangen (Nikotin-Craving),<br />
vermehrter Irritierbarkeit, verminderter Frustrationstoleranz, dysphorischer<br />
oder depressiver Stimmung, Ärger, Aggressivität, Angst, Konzentrationsstörungen,<br />
Unruhe, Schlafstörungen und gesteigertem Appetit äußern können<br />
(American Psychiatric Association, 1980). Tsuda, Steptoe, West,<br />
Fieldman und Kirschbaum (1996) und Tateyama, Hummel, Roscher und<br />
Kobal (1998) fanden außerdem heraus, dass es zu einer vorübergehenden<br />
diastolischen Hypotonie und zu einer orthostatischen Dysregulation kommen<br />
kann. Die meisten Entzugssymptome dauern etwa ein bis vier Wochen<br />
nach dem Rauchstopp an, nur in Ausnahmefällen können sie über mehrere<br />
Monate hinweg bestehen bleiben (Milhorn Jr., 1990). Meistens sind sie<br />
nicht so schwer ausgeprägt wie bei anderen Drogen. Sie sind nicht nur Ergebnis<br />
der biologischen Neuroadaptation, sondern auch eine Folge der psychischen<br />
Abhängigkeit. Vor allem Symptome wie affektive Veränderungen,<br />
Reizbarkeit, eine veränderte Frustrationstoleranz und depressive Verstimmungen<br />
sind häufig durch beide Faktoren bedingt.
Neurobiologie der Nikotinabhängigkeit<br />
Überdosierungen führen je nach Dosis zu Erbrechen, Kopfschmerzen, Tachykardien,<br />
Speichelfluss, abdominalen Schmerzen, kaltem Schweiß, Kopfschmerzen,<br />
Schwindel, Übelkeit, Seh- und Hörstörungen, geistiger Verwirrtheit,<br />
deutlicher Schwachheit, Hypotonie und –thermie, Antidiurese,<br />
Diarrhöe und Tremor (Barthwell, 1994). Bei massiven Überschreitungen<br />
des normalen Dosisbereichs, z.B. durch die Aufnahme reinen Nikotins,<br />
kann es auch zu Bewusstseinsstörungen und komatösen Zuständen kommen.<br />
In der Literatur werden selten auch psychopathologische Merkmale<br />
wie optische Halluzinationen beschrieben (Foulds, 2006). Die Toleranzentwicklung<br />
nach regelmäßiger Zufuhr von Nikotin führt neben den bereits<br />
beschriebenen Anpassungsprozessen des Organismus auch dazu, dass ursprünglich<br />
toxische Dosen gut vertragen werden. Der Effekt der zentralen<br />
Stimulation bleibt jedoch – zumindest subjektiv – erhalten. Bei Normalpersonen<br />
ohne Toleranzentwicklung liegt die letal-toxische Grenze bei circa<br />
einem Milligramm pro Kilogramm Körpergewicht, starke Raucher vertragen<br />
hingegen zwischen 20 und 40 Milligramm, manchmal sogar 60 Milligramm<br />
ohne wesentliche Intoxikationszeichen (Fagerstrom et al., 1990).<br />
Der Tod tritt bei Überdosierung meist in Folge eines kardiovaskulären Kollaps<br />
mit Blutdruckabfall und unregelmäßigem Herzschlag, Krämpfen und<br />
Aussetzen der Atmung ein (Barthwell, 1994).<br />
Als langfristige Schädigungen beim Raucher werden vor allem Lungenkrebs,<br />
Krebserkrankungen im Bereich des Rachens, Krebserkrankungen an<br />
der Harnblase, der Niere und der Bauchspeicheldrüse, Schlaganfall, Erkrankungen<br />
der Herzkranzgefäße, Raucherbeine, grauer Star, Störungen des<br />
Geruchssinns, eingeschränktes körperliches Leistungsvermögen, Atemnot<br />
(= Dyspnoe), Hautveränderungen und Unfruchtbarkeit bzw. Impotenz angeführt<br />
(Industriegewerkschaft Metall, 1992).<br />
Ein hohes Risiko besteht auch für Nichtraucher in Raucherumgebungen. Im<br />
Zusammenhang mit Tabak wurden in den USA pro Jahr 5000 Nichtrauchertote<br />
registriert. Kinder aus Raucherhaushalten kommen im ersten Lebensjahr<br />
außerdem deutlich häufiger wegen Erkrankungen der Atemwege, Mittelohrentzündung<br />
oder Nebenhöhlenentzündung ins Krankenhaus. Passiv-<br />
65
66<br />
Neurobiologie der Nikotinabhängigkeit<br />
raucher sind vor allem von kardiovaskulären Erkrankungen, Lungenkrebs<br />
und Asthmaattacken betroffen (Bölcskei & Wagner, 1989).<br />
3.8. Olfaktorisches und trigeminales System<br />
Wie in Kapitel 1.5. bereits beschrieben, besitzt Nikotin sowohl olfaktorische<br />
als auch trigeminale Eigenschaften. Von beiden Komponenten wird angenommen,<br />
dass sie sowohl bei der Entwicklung der Abhängigkeit als auch im<br />
Rahmen klassischer Konditionierungsprozesse und somit bei der Auslösung<br />
von Rückfällen eine wichtige Rolle spielen. Da beide Systeme auch im<br />
Rahmen der in dieser Arbeit dargestellten Untersuchung auf ihren Einfluss<br />
auf die Entstehung und die Stärke von Craving und die Einbindung in klassische<br />
Konditionierungsprozesse untersucht werden sollen, werden sie im<br />
folgenden Kapitel kurz hinsichtlich ihres neurobiologischen Aufbaus dargestellt.<br />
Olfaktorisches System<br />
Die Wahrnehmung olfaktorischer Reize beginnt wie bei anderen Sinnen<br />
ebenfalls direkt im Organ. In der Nase findet dieser Prozess in der Regio<br />
olfactoria der Nasenschleimhaut statt, die sich in der mittleren Nasenmuschel<br />
befindet (Albrecht & Wiesmann, 2006). Hier finden sich olfaktorische<br />
Rezeptorneuronen, deren Axone zu den Bulbi olfactorii ziehen. Auf den<br />
Flimmerhärchen, den so genannten Zilien, befinden sich olfaktorische Rezeptoren,<br />
die als Schlüsselstellen der olfaktorischen Signaltransduktion<br />
angesehen werden. Innerhalb des Bulbus olfactorius bilden die Axone Synapsen<br />
mit den nachgeschalteten Neuronen, den Mitralzellen. Diese Verschaltung<br />
zwischen olfaktorischem Epithel und dem Bulbus olfactorius<br />
erfolgt dabei für alle olfaktorischen Rezeptorneuronen mit demselben Rezeptor<br />
konvergent. Auf Ebene des Bulbus wird also eine Art Zusammenschaltung<br />
von Nervenzellen mit gleichen Charakteristika in den so genannten<br />
Glomeruli vollzogen, die die Schaltstellen mit den Mitralzellen beinhalten<br />
(Albrecht & Wiesmann, 2006). Die Axone der letztgenannten folgen<br />
dann dem Tractus olfactorius und projizieren in der Mehrzahl direkt auf<br />
piriforme und entorhinale Rindenareale des Gehirns, sowie zur Amgydala,<br />
die mit der Verarbeitung von Emotionen und Erinnerungen in Verbindung
Neurobiologie der Nikotinabhängigkeit<br />
gebracht werden (Anderson et al. 2003; Small, Voss, Mak, Simmons, Parrish<br />
& Gitelman, 2004). Diese Verschaltung in der zentralen Anatomie wird<br />
für den im Vergleich zu anderen sensorischen Kanälen stark ausgeprägten<br />
emotionalen Charakter vieler olfaktorischer Gedächtnisinhalte als mit verantwortlich<br />
angesehen (Herz, 2000). Ein kleiner Anteil der Axone verläuft<br />
über den Thalamus zum orbitofrontalen Kortex (Edwards, Mather, Shirley<br />
& Dodd, 1987). Die Mehrzahl aller Fasern projiziert im Unterschied zu<br />
anderen Sinnesmodalitäten ungekreuzt auf ipsilaterale Hirnareale. Bisher ist<br />
es jedoch nicht gelungen, einen eigentlichen olfaktorischen Kortex beim<br />
Menschen zu identifizieren. Es wird aber in zahlreichen Arbeiten auf die<br />
Bedeutung orbitofrontaler Rindenareale bei der Verarbeitung von Geruchsreizen<br />
hingewiesen (z.B. Zatorre, Jones-Gotman, Evans & Meyer, 1992).<br />
Trigeminales System<br />
Das trigeminale System findet sich sowohl im Bereich der Mund- als auch<br />
der Nasenschleimhaut und ist für die somatosensorische Innervation, also<br />
für die Wahrnehmung von Temperatur, Schmerz und Berührung zuständig.<br />
Beschreibungen von Sensationen, die den trigeminalen Nerven zuzuordnen<br />
sind, sind stechend, juckend, brennend und prickelnd (Green &<br />
Lawless, 1991). Sensorische Fasern in den trigeminalen Nerven beinhalten<br />
entsprechend Mechanorezeptoren (schnelle und langsame Adaptation),<br />
Thermorezeptoren (Reaktion auf kalte und warme Reize), Nozizeptoren<br />
(Reaktion auf Schmerzreize) und Propiozeptoren (Reaktion auf Muskel-<br />
oder Gelenkposition). Sie sind außerdem sensitiv für chemische Reize,<br />
weswegen man davon ausgeht, dass sie in der Evolutionsgeschichte den<br />
Sinn eines Schutzes vor giftigen Substanzen erfüllten (Silver & Finger,<br />
1991). Sie verzweigen sich in der nasalen Schleimhaut sehr früh und enden<br />
in freien Nervenendigungen. Manche von ihnen durchqueren das respiratorische<br />
Zellgewebe und enden nur einen Mikrometer unter der Hautoberfläche.<br />
Deswegen nimmt man an, dass chemische Stimuli direkt mit den trigeminalen<br />
Nervenendigungen interagieren und so die relativ kurzen Latenzzeiten<br />
nach Stimulation zu erklären sein könnten. Freie Nervenendigungen<br />
scheinen zudem auch als Effektoren zu dienen und durch Axonreflexe einige<br />
Eigenschaften des Zellgewebes zu verändern, welche die Wahrnehmung,<br />
Verarbeitung und Weiterleitung anderer Rezeptoren beeinflussen. Sie inhi-<br />
67
68<br />
Neurobiologie der Nikotinabhängigkeit<br />
bieren z.B. olfaktorische durch die Aktivierung trigeminaler Rezeptoren.<br />
Wahrscheinlich sind sie Teil der Gruppe der dünnen nicht-myelinisierten C-<br />
Fasern oder der dünnen myeliniserten Ad-Fasern, die generell mit Schmerz<br />
korreliert sind (Kobal & Hummel, 1991). Dabei werden erstgenannte für die<br />
Vermittlung von brennenden Sensationen, letztgenannte für die Weiterleitung<br />
von als stechend wahrgenommenen Empfindungen verantwortlich<br />
gemacht (Hummel & Livermore, 2002). Elektrophysiologische Ableitungen<br />
ergaben in den meisten Fällen deutlich höhere Schwellenwerte für trigeminale<br />
Konzentrationen als für olfaktorische Reize der gleichen Substanz<br />
(Silver & Finger, 1991). In Abbildung 8 sind noch einmal die wichtigsten<br />
trigeminalen Areale zu sehen.<br />
Abbildung 8: Das trigeminale System 7<br />
Auch das trigeminale System ist neben dem olfaktorischen maßgeblich an<br />
der Wahrnehmung von Duftstoffen beteiligt. Fast alle bekannten Substanzen<br />
lösen neben einer olfaktorischen Aktivierung zumindest in hohen Konzentrationen<br />
auch eine trigeminale Empfindung aus (Elsberg, Levy & Brewer,<br />
1935; Hummel, Doty & Yousem, 2005). Bei psychophysischen Tes-<br />
7 aus St. Joseph´s Hospital, 2009 (© by Staywell Custom Communications)
Neurobiologie der Nikotinabhängigkeit<br />
tungen des intranasalen trigeminalen Systems stößt man auf das Problem,<br />
dass die olfaktorische Schwelle einer Substanz immer niedriger liegt als die<br />
trigeminale und somit immer olfaktorische Einflüsse mit erfasst werden.<br />
Das olfaktorische und das trigeminale System sind eng miteinander verknüpft<br />
(Hummel & Livermore, 2002). So weisen Patienten mit Anosmie,<br />
der Unfähigkeit Gerüche wahrzunehmen, ebenfalls eine deutlich reduzierte<br />
trigeminale Sensibilität auf (Boyle, Heinke, Gerber, Frasnelli & Hummel,<br />
2007). Außerdem scheint der trigeminale Anteil mit steigender Konzentration<br />
eines Stoffes mit beiden Eigenschaften den Geruchsanteil zu unterdrücken,<br />
während bei niedrigen Konzentrationen die olfaktorische Wahrnehmung<br />
überwiegt (Green & Lawless, 1991; Kobal & Hummel, 1988; Livermore,<br />
Hummel & Kobal, 1992).<br />
3.9. Vergleich der Nikotinabhängigkeit mit und Abgrenzung<br />
zu anderen Süchten<br />
Allgemein werden immer wieder Gemeinsamkeiten zwischen Nikotin und<br />
non-nikotinischen Drogen berichtet. So gleichen sie sich hinsichtlich der<br />
Tatsache, dass Tiere sich diese Substanzen ohne Zwang selbst administrieren.<br />
Außerdem bestehen Gemeinsamkeiten hinsichtlich der subjektiven<br />
Effekte, dem zwanghaften Konsum, der eingeschränkten Konsumkontrolle,<br />
dem fortgesetzten Konsum trotz schädlicher Konsequenzen, der hohen und<br />
schnellen Rückfallrate nach einem Abstinenzversuch, der Toleranzentwicklung,<br />
dem Auftreten von Entzugssymptomen und dem schnellen Wiedereinsetzen<br />
des Konsumverhaltens nach einem einzelnen Fehltritt. Außerdem<br />
entwickeln alle Arten von Drogen ihre abhängig machenden Effekte über<br />
das dopaminerge System, sind leicht konditionierbar und werden durch den<br />
Genotyp beeinflusst. Es gibt jedoch auch eine Reihe von Unterschieden, die<br />
dem Nikotin unter den abhängig machenden Substanzen eine Sonderrolle<br />
zukommen lassen. So ist Nikotin die einzige Droge im DSM, die nicht<br />
durch Diagnosekriterien zu Intoxikation und drogeninduzierten psychischen<br />
Störungen gekennzeichnet ist. Es wird angenommen, dass diese fehlenden<br />
Schädigungen zur Abhängigkeitsentwicklung beitragen, weil sie den Betroffenen<br />
ermöglichen, über sehr lange Zeitspannen große Mengen an Nikotin<br />
69
70<br />
Neurobiologie der Nikotinabhängigkeit<br />
aufzunehmen, ohne Schwierigkeiten im Alltag zu bekommen (Hughes,<br />
2007). Dies könnte auch der Grund dafür sein, dass die Nikotinabhängigkeit<br />
lange nicht als Abhängigkeit gesehen wurde. Entsprechend ist das Rauchen<br />
wahrscheinlich auch eine der häufigsten und am meisten geduldeten süchtigen<br />
Verhaltensweisen beim Menschen, so dass Automatisierungsprozesse<br />
bei der Nikotinabhängigkeit deutlich stärker ausgeprägt sind als bei anderen<br />
Drogen. Ein Drittel aller Menschen, die jemals eine Zigarette probiert haben,<br />
entwickeln in der Folge eine Nikotinabhängigkeit (Shiffman, 1989).<br />
Henningfield, Cohen und Slade (1991) stellten zudem fest, dass nur 10%<br />
aller Raucher weniger als fünf Zigaretten am Tag rauchen. Im Vergleich zu<br />
Opiaten, die einen großen Dopaminüberschuss außerhalb des Nucleus accumbens<br />
induzieren, der mit Euphorie assoziiert ist und die verstärkenden<br />
Eigenschaften der Droge potenziert, fällt dieser Effekt bei Nikotin sehr<br />
klein aus. Jedoch hat Nikotin die Fähigkeit, Umweltreize in ihren verstärkenden<br />
Eigenschaften zu potenzieren, was für Opiate nicht demonstriert<br />
werden konnte (Balfour et al., 2000). Anders als diese desensitiert Nikotin<br />
außerdem die angesprochenen Rezeptoren, steigert deren Reaktionsbereitschaft<br />
und wirkt dort biphasisch.<br />
Das Konzept der Toleranzentwicklung, unter dem in Diskussionen über<br />
Drogenabhängigkeit häufig der Rückgang verstärkender und subjektiver<br />
Effekte der Droge über die Zeit gemeint ist, bestätigen Raucher nicht. Statt<br />
des zu erwartenden eskalierenden Gebrauchs berichten die meisten erwachsenen<br />
Nikotinkonsumenten keine Dosissteigerung über die Jahre hinweg.<br />
Auch das Kriterium, zu einer bestimmten Gelegenheit mehr zu konsumieren<br />
als ursprünglich gewollt, erfüllen nur wenige Betroffene (Breslau, Kilbey &<br />
Andreski, 1994). Ähnliches gilt für die Diagnosevoraussetzungen, viel Zeit<br />
für die Beschaffung, den Gebrauch und die Erholung von der Droge zu<br />
investieren, sowie Aktivitäten aufzugeben (Breslau et al., 1994), um die<br />
Drogen konsumieren zu können. Dies könnte jedoch möglicherweise darauf<br />
zurückzuführen sein, dass Nikotin legal und deswegen überall erhältlich ist<br />
und außerdem kaum intoxicierende Effekte hat.<br />
Zusammenfassend sehen Nikotinforscher momentan offensichtlich nur<br />
einen eingeschränkten Wert in den DSM- oder ICD-Kriterien für die Niko-
Neurobiologie der Nikotinabhängigkeit<br />
tinabhängigkeit (Breslau et al., 1994; Henningfield, Fant, Buchhalter &<br />
Stitzer, 2005; West, 2006). Validierungsstudien für andere Kriterien konnten<br />
deutlich bessere Werte erzielen als die beiden Klassifikationssysteme<br />
(West, 2006). So zeigte z.B. eine Studie eine deutliche Überlegenheit des<br />
Fagerström-Tests und des einfachen Kriteriums „Anzahl der Zigaretten pro<br />
Tag“ in der Vorhersage der Unfähigkeit, das Rauchen aufzugeben (Henningfield<br />
et al., 2005).<br />
3.10. Zusammenhang des Nikotinkonsums mit psychiatrischen<br />
Krankheitsbildern<br />
Batra (2000) und Kirch (2000) fanden eine deutlich erhöhte Raucherprävalenz<br />
bei Menschen mit psychischen Störungen. Dazu zählten in erster Linie<br />
die Alkohol- und Drogenabhängigkeit, schizophrene Störungen (zwei- bis<br />
dreifach erhöht) und depressive Erkrankungen (zweifach erhöht). Für den<br />
Bereich der affektiven Störungen wurden verschiedene Hypothesen über die<br />
beobachtete Koinzidenz aufgestellt. Kendler, Neale, MacLean, Heath, Eaves<br />
und Kessler (1993) gehen von einer gemeinsamen genetischen Belastung<br />
aus, die mit Veränderungen und Auffälligkeiten im serotonergen<br />
Stoffwechsel verbunden ist. Dem Rauchen wird gleichzeitig aber auch eine<br />
antidepressive Wirkung zugeschrieben, was auch für die These einer<br />
Selbstmedikation sprechen könnte. Durch die entstehende geringere Konzentration<br />
und Aktivität der Monoaminoxidase in den Thrombozyten<br />
kommt es zu einem verminderten Abbau von monoaminergen Neurotransmittern<br />
und damit zu einer erhöhten Verfügbarkeit von Serotonin (Norman,<br />
Chamberlain & French, 1987). Stage, Glassman und Covey (1996) gehen<br />
außerdem von einer verminderten Abstinenzfähigkeit bei Rauchern mit<br />
einer Majoren Depression in der Vorgeschichte aus, da im Entzug 75%<br />
schwere depressive Symptome entwickeln. Im Vergleich dazu sind Menschen<br />
ohne bekannte affektive Störungen nur zu 30% von entsprechenden<br />
Beschwerden betroffen.<br />
Bei schizophrenen Störungen konnten Verbesserungen in verschiedensten<br />
Bereichen beobachtet werden, die mit dem Rauchen einhergehen. Dazu<br />
71
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Neurobiologie der Nikotinabhängigkeit<br />
zählen neben einer Antriebssteigerung bei vorherrschender Negativsymptomatik<br />
(Sandyk & Kay, 1991) und den Verbesserungen der kognitiven<br />
Einschränkungen (Sacco, Termine, Seyal, Dudas, Vessicchio, Krishnan-<br />
Sarin, Jatlow, Wexler & George, 2005), die durch die Neuroleptika auftreten<br />
(Levin et al., 1996), auch die nikotinvermittelte Inhibition affektiver<br />
psychotischer Übererregtheit (Neuwirth, Andresen, Seifert, Strak, Spehr,<br />
Thomasius & Rosenkranz, 1995), sowie die Ausblendefähigkeit für akustische<br />
Stimuli, die aufgrund einer neurobiologischen Dysfunktion nicht mehr<br />
funktioniert (Dursun & Kutcher, 1997). Die Effekte des Nikotins werden<br />
hier dem Ausgleich zugrunde liegender Defizite im dopaminergen System<br />
zugeschrieben (Kirch, 2000).<br />
Bei Alkohol- und Drogenabhängigkeit scheint Nikotin in der Lage zu sein,<br />
alkoholbedingte kognitive Einschränkungen partiell zu kompensieren, was<br />
sich vor allem in der Wahrnehmungs- und Reaktionsfähigkeit bemerkbar<br />
macht. Außerdem scheint die Schwere der Nikotinabhängigkeit mit der<br />
Stärke des Cravings nach Alkohol zusammenzuhängen, was für einen gemeinsamen<br />
pathophysiologischen Mechanismus spricht (Hillemacher, Bayerlein,<br />
Wilhelm, Frieling, Thürauf, Ziegenbein, Kornhuber & Bleich, 2006).<br />
Im Bereich neurodegenerativer Erkrankungen konnten Balfour und Fagerstrom<br />
(1996) bei Parkinson-Erkrankten nach experimenteller Nikotinzufuhr<br />
eine Befundverbesserung feststellen. Bei Morbus-Parkinson handelt es<br />
sich um eine Erkrankung, die durch extrapyramidale Effekte wie Ruhetremor,<br />
Steifheit, Bradykinesie (verlangsamte Bewegungen) und Verlust der<br />
posturalen Reflexe (Gleichgewichtsreflexe) gekennzeichnet ist und als Folge<br />
einer Dysfunktion des nigrostriatalen dopaminergen Systems auftritt.<br />
Diese Fehlfunktion geht wiederum mit der Degeneration dopaminerger<br />
Neurone in der Substantia Nigra einher. Nikotin scheint die Dopaminausschüttung<br />
und die dopaminerge Transmission im Striatum zu erleichtern, was<br />
zu einer Linderung der nigrostriatalen extrapyramidalen Beschwerden führen<br />
könnte. Außerdem schreibt man Nikotin neuroprotektive Eigenschaften<br />
zu, die dopaminerge Neurone in der Substantia Nigra vor neurotoxischer<br />
Zerstörung schützen könnten (Arneric, 2000; Newhouse & Whitehouse,<br />
2000).
Neurobiologie der Nikotinabhängigkeit<br />
Ebenfalls zu den neurodegenerativen Erkrankungen zählt die Alzheimer-<br />
Demenz, die mit der Bildung von amyloiden Plaques, das heißt Ablagerungen<br />
im extrazellulären Raum, verbunden ist, die dem Gewebe eine wachsartige<br />
Beschaffenheit verleihen und Funktionseinschränkungen nach sich<br />
ziehen. Außerdem bilden sich neurofibrilläre Tangles, die als fadenartige<br />
Strukturen im Gehirn in Erscheinung treten. Weiterhin zeigt sich ein abnormer<br />
zerebraler Blutfluss im parietotemporalen Kortex, der durch Nikotin<br />
wieder normalisiert werden kann (Newhouse & Whitehouse, 2000).<br />
Auch bei Aufmerksamkeitsstörungen und Hyperaktivität kommt es wahrscheinlich<br />
durch die Reduktion der Unzulänglichkeiten der kortikalen cholinergen<br />
und dopaminergen Transmission (Arneric, 2000) zu einer nikotinvermittelten<br />
Aufmerksamkeitssteigerung und einer dopaminergen Stimulation<br />
(Levion et al., 1996; Pomerleau, Downey, Stetson & Pomerleau, 1995).<br />
Dursun et al. (1997) fanden außerdem heraus, dass beim Gilles-de-la-<br />
Tourette-Syndrom motorische und sprachliche Tics unter Nikotin seltener<br />
auftreten. Für die Wirkung des Nikotins bei diesem Krankheitsbild haben<br />
die Autoren verschiedene Hypothesen formuliert. So könnten hypersensitive<br />
nikotinische Rezeptoren im Gehirn durch Nikotingabe desensitisiert werden.<br />
Hypersensitive postsynaptische Dopaminrezeptoren könnten als Resultat<br />
der erhöhten Dopaminausschüttung ebenfalls desensitisieren. Weiterhin<br />
besteht die Möglichkeit, dass hypersensitive 5-HAT-Rezeptoren durch<br />
chronische Nikotingabe in ihrer Dichte erhöht und so möglicherweise die<br />
Interaktionen zwischen exzitatorischen und inhibitorischen Subtypen verändert<br />
werden könnten. Schließlich könnte auch ein zentraler hypernoradrenerger<br />
Zustand durch die Abnahme von Noradrenalin im Gehirn durch<br />
Nikotingabe für die Wirkung verantwortlich sein.<br />
Bei Angststörungen haben nur bestimmte nikotinische Acetylcholinrezeptor-Liganden<br />
eine anxiolytische Wirkung, die wiederum an bestimmte nikotinische<br />
Acetylcholinrezeptorsubtypen gekoppelt zu sein scheint (Arneric,<br />
2000). In einigen Studien hat sich Nikotin auch als Analgetikum als wirksam<br />
erwiesen. Die schmerzlindernde Wirkung wird wahrscheinlich über die<br />
Aktivierung von Zellen in subkortikalen Arealen vermittelt, die zur Ausschüttung<br />
von Acetylcholin führen und über die Aktivierung von absteigen-<br />
73
74<br />
Neurobiologie der Nikotinabhängigkeit<br />
den schmerzinhibierenden Nervenbahnen den Schmerz modulieren (s. Arneric,<br />
2000). Auch bei Colitis ulcerosa, einer akuten Magen-Darm-<br />
Erkrankung, bei Störungen der Prostatafunktion und bei Schlafapnoe konnten<br />
Verbesserungen durch Nikotin beobachtet werden.<br />
Generell stellt sich beim Einsatz von Nikotin als Therapeutikum jedoch das<br />
Problem der starken Nebenwirkungen und der negativen Wahrnehmung von<br />
Nikotin in der Öffentlichkeit. Um tatsächlich einen weit reichenden therapeutischen<br />
Einsatz erreichen zu können, müssen also erst selektive nikotinische<br />
Acetylcholinliganden mit geringer ausgeprägten Nebenwirkungen<br />
gefunden werden.<br />
Abschließend lässt sich festhalten, dass es sich bei Nikotinabhängigkeit um<br />
ein sehr komplexes Störungsbild handelt, bei deren Entwicklung eine Vielzahl<br />
von Faktoren beteiligt ist. Neben einem frühen Konsumbeginn mit der<br />
zugehörigen Neuroadaptation, der schnell einsetzenden Drogenwirkung, der<br />
Fähigkeit des Nikotins zu entspannen oder zu stimulieren, der rasch erfolgenden<br />
Aktivierung, dem kurzen und regelmäßigen Konsumintervall, der<br />
Konditionierung auf eine Vielzahl von Reizen, die mit dem alltäglichen<br />
Leben verquickt sind, der oralen Befriedigung und dem sensumotorischen<br />
Handling, scheinen auch Variablen wie Gewichtsverlust, die Möglichkeit<br />
zur selbstständigen Dosisanpassung an eigene Bedürfnisse und die assoziierten<br />
Veränderungen im Selbstbild eine wesentliche Rolle zu spielen<br />
(Block & Buchkremer, 1991).
Therapie der Nikotinabhängigkeit<br />
4. Therapie der Nikotinabhängigkeit<br />
Für die Therapie der Nikotinabhängigkeit sind in den letzten Jahrzehnten<br />
unterschiedlichste Methoden getestet worden. Einige davon werden heute<br />
wegen mangelnder Effektivität oder aus moralischen Gründen nicht mehr<br />
eingesetzt. Dennoch gibt es auch heute eine Vielzahl unterschiedlicher Methoden,<br />
die bei der Raucherentwöhnung angewendet werden. Im folgenden<br />
Kapitel soll eine Auswahl von Interventionsmöglichkeiten vorgestellt werden.<br />
4.1. Erfolgsprädiktoren in der Raucherentwöhnung<br />
Wie bereits angedeutet, beschäftigten sich die Untersuchungen zur Raucherentwöhnung<br />
in den letzten Jahrzehnten nicht nur mit der Wirksamkeit<br />
einzelner Interventionen, sondern auch mit verschiedenen Variablen, für die<br />
ein Zusammenhang mit einem Behandlungserfolg angenommen wurde.<br />
Dabei ergab sich z.B. für das Kriterium, wie viel Zeit morgens nach dem<br />
Aufstehen vergeht, bis die erste Zigarette geraucht wird, eine negative Korrelation<br />
mit dem Ansprechen auf eine Therapie. Je kürzer der Zeitabschnitt,<br />
desto schlechter schnitten die Teilnehmer in der Behandlung ab (Balfour &<br />
Fagerstrom, 1996). Weiterhin wurde festgestellt, dass Menschen mit häufigeren<br />
Aufhörversuchen nach der Therapie weniger rauchten, tendenziell<br />
waren auch mehr erfolgreich Abstinente unter ihnen zu finden. Für die Variablen<br />
Alter, Beruf und Geschlecht konnte Huber (1992) keine Vorhersagekraft<br />
für den Erfolg in der Raucherentwöhnung feststellen, ein hoher<br />
Zigarettenkonsum ging allerdings eher mit niedrigerer Schulbildung einher.<br />
Andere Untersuchungen konnten dagegen Unterschiede in diesen Merkmalen<br />
feststellen (Minneker, Unland & Buchkremer, 1989; Stögbauer & Unland,<br />
1991), so dass weitere Studien für eine abschließende Bewertung<br />
erforderlich sind. Die Unterstützung durch den Partner hat sich generell als<br />
positiver Prädiktor erwiesen und auch eine geringe Belastung vor Therapiebeginn<br />
stellte einen guten Prognosefaktor dar (Ernst, 1989; Minneker &<br />
Buchkremer, 1989).<br />
75
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Therapie der Nikotinabhängigkeit<br />
4.2. Psychotherapeutische Ansätze<br />
Psychotherapeutische Ansätze sind bis heute die als am wirkungsvollsten<br />
eingeschätzten Behandlungsverfahren bei Nikotinabhängigkeit. Deswegen<br />
sollen sie in diesem Kapitel auch an den Anfang gestellt werden. Grundsätzlich<br />
gilt für alle psychotherapeutischen Verfahren, dass die Selbstwirksamkeitserwartung<br />
des Patienten, die so genannte self-efficacy (Bandura, 1982),<br />
beim Patienten von entscheidender Bedeutung für den Erfolg ist. Bei der<br />
Erwartung von Misserfolg besteht die Gefahr einer sich selbst erfüllenden<br />
Prophezeiung. So sehen die Betroffenen Rückfälle z.B. nicht als Ausnahme,<br />
die passieren kann und darf, sondern gehen davon aus, dass ihr Versagen<br />
die Normalität darstellt. Dies kann den Behandlungserfolg stark gefährden.<br />
Nach Prochaska, diClemente und Norcross (1992) durchläuft der Entwöhnungsprozess<br />
auch beim Rauchen fünf verschiedene Phasen. In der ersten<br />
Phase der Präkontemplation besteht noch keine Änderungsbereitschaft. In<br />
der zweiten Phase der Kontemplation merkt der Patient bereits, dass sein<br />
Verhalten problematisch ist und beginnt über eine Verhaltensänderung<br />
nachzudenken. In der Präparationsphase werden dann bereits kleine Veränderungen<br />
im Verhalten eingeleitet, während in der Aktionsphase erfolgreiche<br />
Veränderungen der Gewohnheiten sichtbar werden. Nicht zu vernachlässigen<br />
ist schließlich die Aufrechterhaltungsphase, in der Erfolge gehalten<br />
und Rückfälle verhindert werden. Die meisten Menschen durchlaufen diesen<br />
Prozess jedoch nicht linear, sondern springen zwischen den verschiedenen<br />
Stufen hin und her, bevor sie einen Langzeiterfolg erreichen. Revenstorf,<br />
Henrich und Brengelmann (1987) fanden dem Phasenmodell entsprechend,<br />
dass 98% der Raucher die Gefährlichkeit des Rauchens anerkennen,<br />
jedoch eine Einstellungs- einer Verhaltensänderung vorausgehen muss.<br />
Mit Hilfe von Kreuz- und Partialkorrelationen konnten sie bestätigen, dass<br />
Raucher, die ihre Meinung zum Konsum geändert hatten, diesen auch signifikant<br />
senkten. Auch Block und Buchkremer (1991) fanden heraus, dass die<br />
Förderung kognitiver Variablen wie einer positiven Erfolgserwartung, und<br />
förderliche Selbstinstruktionen vor allem bei Frauen wichtige Bestandteile<br />
eines Entwöhnungsprogramms sein sollten, während bei Männern in erster<br />
Linie der Wunsch nach sozialer Unterstützung, gleichzeitig aber auch die<br />
Tendenz zu Abgrenzung und reaktivem Widerstand Beachtung finden soll-
Therapie der Nikotinabhängigkeit<br />
ten. Rehms, Buchkremer und Stögbauer (1991) betonen ebenfalls die Wichtigkeit<br />
kognitiver Bewältigungsstrategien, der Fähigkeit, Stresssituationen<br />
oder eigene Stressreaktionen umzudeuten, einer internalen Kontrollerwartung<br />
und verhaltensbezogener Copingstrategien für das abstinent Bleiben.<br />
Dabei stehen aktive Kontrollversuche zur Stressbewältigung bei Männern<br />
und eine geringe Bereitschaft, auf Stress emotional und resignativ zu reagieren<br />
bei Frauen im Vordergrund. Die Rückfallwahrscheinlichkeit ist nach<br />
Meinung von Rehms et al. (1991) erhöht, wenn Raucher die Einstellung<br />
haben, ihr Verhalten sei stärker von äußeren Umständen und Zufällen bestimmt,<br />
wenn häufig negative Selbstgespräche stattfinden und allgemein auf<br />
Belastungen eher emotional betroffen reagiert wird.<br />
Carlson (1994) unterteilt psychotherapeutische Behandlungsverfahren in<br />
drei große Gruppen. Dabei rechnet er zu der ersten Kategorie der Aversionsstrategien<br />
vor allem elektrische Schocks in Verbindung mit dem Rauchen.<br />
Die im Hintergrund stehende Theorie geht dabei von einer reziproken<br />
Hemmung habituell gewordener Verhaltensweisen aus. Durch die Darbietung<br />
eines elektrischen oder generell aversiven Reizes soll die unerwünschte<br />
Reaktion gehemmt oder eliminiert werden. Dieser kann mit der Reaktion<br />
gleichzeitig präsentiert werden oder er kann mit rauchassoziierten Auslösern<br />
gekoppelt werden. Die stärker mit Schmerz und Angst assoziierte Reaktion<br />
soll die Wahrscheinlichkeit des Auftretens von gewohnten mit Belohnung<br />
assoziierten Verhaltensweisen, in diesem Falle dem Rauchen, verringern.<br />
Auch die Techniken der negativen Übung, wie Erschöpfung, Sättigung<br />
oder Löschung zählt er zu der Gruppe der Aversionsstrategien. Hier<br />
wird eine Reaktion mehrfach wiederholt. Beim Rauchen bedeutet dies ein<br />
massiertes Üben bzw. Schnellrauchen. Nachteile dieser Techniken sind eine<br />
massive Belastung des Herz-Kreislauf-Systems, das Hervorrufen von anderen<br />
Stressreaktionen und das fehlende Training von Verhaltensfertigkeiten,<br />
die einen Rückfall verhindern könnten.<br />
Die zweite Gruppe besteht aus Selbstkontrollmethoden, zu denen die Veränderung<br />
der Umgebung (z.B. Veränderung der Orte, an denen normalerweise<br />
geraucht wurde), Verhaltensprogrammierung (Bestrafung und Belohnung)<br />
und kognitive Kontrolle (Änderung der Einstellung zum Rauchen)<br />
77
78<br />
Therapie der Nikotinabhängigkeit<br />
zählen. Ziel ist es, das Problemverhalten zu analysieren und Bedingungen<br />
zu identifizieren, die das aktuelle Problemverhalten aufrechterhalten. In der<br />
Folge werden Möglichkeiten erarbeitet, das Problemverhalten zu verändern.<br />
Als grundlegend sind hier Selbstmanagementtechniken in den Bereichen<br />
Selbstbeobachtung, Selbstbewertung und Selbstverstärkung anzusehen. Die<br />
für die Abstinenz notwendige Selbstkontrolle, den kurzfristig unangenehmen<br />
Zustand für ein langfristig besseres Lebensgefühl zu überstehen, lässt<br />
sich nur durch diese Techniken erreichen (Kanfer, Reinecker & Schmelzer,<br />
2006). Entsprechend sind die Hauptbestandteile nach Brengelmann (1976)<br />
die genaue Zielvorgabe (In welchem Zeitraum soll die Anzahl der Zigaretten<br />
auf eine bestimmte Menge reduziert werden?), der Einsatz von Verhaltensregeln<br />
zur Kontrolle des Konsums (z.B. nicht beim Essen rauchen),<br />
Methoden der Selbst- oder Fremdverstärkung zur Bekräftigung und Erfüllung<br />
der Regeln (z.B. Anruf beim Therapeuten bei starkem Verlangen zu<br />
rauchen, Verhaltensverträge) und andere Therapiestrategien wie verdeckte<br />
Sensibilisierung (Cautela, 1967) und die kontrollierte Erfüllung der Therapieregeln<br />
(Compliance-Training). Des Weiteren gehören Stimuluskontrolltechniken<br />
in diese Gruppe von Interventionen, bei denen die Selbstkontrolle<br />
als Stimuluskontrolle (z.B. nur in einem bestimmten Stuhl rauchen), als<br />
„self-monitoring“ (z.B. das Führen von Protokollen) oder für das Rauchen<br />
nach einem zufälligen Signalplan (z.B. durch Kopplung an ein akustisches<br />
Signal) eingesetzt werden kann. Im letztgenannten Fall soll durch die Kopplung<br />
an einen neuen Reiz die Verbindung zu den alten Auslösestimuli gelöscht<br />
und dann durch langsame Reduktion des Signals auch die Rauchgewohnheit<br />
reduziert werden.<br />
Die dritte Gruppe bezeichnet Carlson (1994) als Gesundheitsedukation und<br />
meint damit Psychoedukation über die Auswirkungen des Rauchens auf das<br />
Leben des Einzelnen und über Strategien und Fertigkeiten, um selbstständig<br />
Änderungen einleiten zu können (s.a. Antonuccio & Boutilier, 2000). Als<br />
weitere Möglichkeiten zur Unterstützung bei der Raucherentwöhnung bieten<br />
sich Entspannungs- und Stressbewältigungstrainings an.<br />
Trotz dieser Unterteilung empfiehlt Carlson (1994) multimodale Programme<br />
inklusive einer psychopharmakologischen Behandlung und betont vor
Therapie der Nikotinabhängigkeit<br />
allem die Notwendigkeit einer Rückfallprophylaxe, da das Hauptproblem<br />
bei der Aufrechterhaltung, nicht beim Aufhören selbst zu liegen scheint.<br />
Minneker und Buchkremer (1989) dagegen verglichen verschiedene Rückfallpräventionsmethoden<br />
(z.B. spezielle Rückfallprophylaxestrategien, zusätzliche<br />
wöchentliche Stützsitzungen) mit einem Standardprogramm ohne<br />
Rückfallverhütungstraining und fanden nach halbjähriger Katamnese keine<br />
Überlegenheit. Stattdessen trat sogar eher eine negative Tendenz auf, weswegen<br />
die Autoren diese Verfahren als nicht notwendig erachten.<br />
Neben den standardisierten Gruppenprogrammen (z.B. Hirzel & Schippers,<br />
1985; Tölle & Buchkremer, 1989) gibt es selbstverständlich auch eine Reihe<br />
von Selbsthilfebüchern, mit denen der Betroffene zunächst selbst versuchen<br />
kann, das Rauchen zu beenden (Adams & Tidyman, 1987; Hodgson &<br />
Miller, 1985). Die Abstinenzrate nach einem kognitiv verhaltenstherapeutischen<br />
Entwöhnungsprogramm schwankt zwischen 20% und 30%. (Antonuccio<br />
& Boutilier, 2000).<br />
4.3. Pharmakologische Ansätze<br />
4.3.1. Ältere Ansätze<br />
Einer der ersten pharmakotherapeutischen Versuche in Zusammenhang mit<br />
der Raucherentwöhnung fand mit dem nonselektiven nikotinischen Acetylcholin-Rezeptor-Antagonisten<br />
Mecamylamin statt. Zunächst ergaben sich<br />
signifikante Reduktionen der erlebten Nikotinwirkungen in Abhängigkeit<br />
von der verabreichten Dosis, die produzierten Verhaltenseffekte waren<br />
jedoch sehr inkonsistent. Rose und Levin (1991) verabreichten Nikotin und<br />
Mecamylamin gemeinsam, um so eine Antagonist-Agonist-Mixtur herzustellen,<br />
die bei optimaler Wirkung auf die nikotinischen Acetylcholinrezeptoren<br />
vom a4b2-Typ die Entzugssymptome mildern und die verstärkenden<br />
Wirkungen des Nikotins unterdrücken sollte. In verschiedenen klinischen<br />
Studien konnten tatsächlich unter dieser Kombination höhere Abstinenzraten<br />
im Vergleich mit Nikotinsubstitution allein erzielt werden, was das<br />
Konzept der Kombination aus Antagonist und Agonist unterstützen würde.<br />
In anderen Studien wurde jedoch von einem steigenden Konsum berichtet<br />
79
80<br />
Therapie der Nikotinabhängigkeit<br />
(Nemeth-Coslett et al., 1986). Außerdem reduzierten die Nebenwirkungen<br />
die Compliance bei den Aufhörwilligen stark (Rose, Sampson, Levin &<br />
Henningfield, 1989). Viele weitere Medikamente wie Anticholinergika,<br />
Sedativa, Tranquilizer, Sympathomimetika, Antikonvulsiva (Alsagoff &<br />
Lee, 1993), Clonidin, Naltrexon und Silbernitrat (Hughes, 1993) wurden<br />
mit enttäuschenden Ergebnissen untersucht.<br />
4.3.2. Bupropion<br />
Bei Bupropion (Handelsname Zyban©) handelt es sich um ein nicht trizyklisches<br />
Antidepressivum, das präsynaptische dopaminerge und noradrenerge<br />
Mechanismen inhibiert und so Einfluss auf die zentralen dopaminergen<br />
Nervenbahnen nimmt. Man geht davon aus, dass die Regulation dieser<br />
Systeme zu einem als geringer empfundenen Craving bei Patienten unter<br />
Nikotinabstinenz führt. Bupropion scheint also ein Antagonist für nikotinische<br />
Acetylcholinrezeptoren zu sein. In klinischen Studien wurde eine zweifach<br />
höhere Abstinenz im Vergleich zu Placebotherapie festgestellt (Hughes,<br />
Stead & Lancaster, 2007). Außerdem reduzierte sich die Gewichtszunahme<br />
deutlich (Jorenby, Leischow, Nides, Rennard, Johnston, Hughes,<br />
Smith, Muramoto, Daughton, Doan, Fiore & Baker, 1999). Nebenwirkungen<br />
traten in 6-8% aller Fälle auf, was bis zu einem Drittel Abbrecher unter<br />
den Behandelten führte (Jorenby et al., 1999). Dazu zählten ein hohes<br />
Krampfrisiko (1:1000), Insomnie, Unruhe, dermatologische oder allergische<br />
Reaktionen, Kurzatmigkeit, Engegefühl in der Brust, Ausschlag, Jucken und<br />
Mundtrockenheit (Lancaster & Stead, 2007). Wegen des hohen Risikos von<br />
Nebenwirkungen gilt diese Substanz generell nur als Mittel zweiter Wahl in<br />
der Entwöhnungsbehandlung (Silveira Balbani & Cortez Montovani, 2005).<br />
4.3.3. Nikotinsubstitution<br />
Nikotin wird nicht nur als Therapeutikum für den Einsatz bei neuropsychatrischen<br />
Krankheitsbildern diskutiert. Es wird bereits seit vielen Jahren<br />
in der Raucherentwöhnung eingesetzt. Da Nikotin als der wichtigste abhängig<br />
machende Bestandteil des Tabakrauchs angesehen wird, für die hohen<br />
Erkrankungsrisiken aber in erster Linie die anderen Komponenten des
Therapie der Nikotinabhängigkeit<br />
Rauchs verantwortlich gemacht werden, scheint es eine gute Möglichkeit zu<br />
sein, Rauchern im Entwöhnungsprozess eine Substitution bieten zu können.<br />
Nikotinsubstitution ist in verschiedenen Darreichungsformen entwickelt<br />
worden. Aktuell auf dem Markt erhältlich sind das Nikotinpflaster, der<br />
Nikotinkaugummi und die Sublingualtablette. Der Nikotininhaler und das<br />
Nikotinnasenspray sind in Deutschland nicht mehr zu erwerben, jedoch gibt<br />
es im Internet die Möglichkeit zum Kauf. Der Kaugummi wurde Anfang der<br />
70er Jahre in Schweden entwickelt und ist seit 1981 in Deutschland erhältlich.<br />
Sublingualtabletten sind seit Oktober 2004 in Deutschland zu erwerben.<br />
Sie werden unter die Zunge gelegt. Ziel ist die Verminderung des<br />
Rauchverlangens und die Abschwächung der Entzugserscheinungen. Außerdem<br />
soll eine Ersatzform zu der gewohnten oralen Aktivität geboten<br />
werden. Zusätzlich liegen auch Hinweise für positive Effekte im Hinblick<br />
auf eine Gewichtszunahme vor (Stitzer & Gross, 1988). Als unerwünschte<br />
Nebenwirkungen werden ein Reizzustand in Mund und Rachen, Magenbeschwerden,<br />
Übelkeit, Schluckauf, vermehrter Speichelfluss, Mundulzera,<br />
Kieferbeschwerden und Zittrigkeit genannt. In verschiedenen Studien konnte<br />
eine deutliche Reduktion der Entzugssymptomatik, sowie eine Überlegenheit<br />
des Kaugummis über ein Placebo festgestellt werden. Nach einer<br />
Metaanalyse von Silagy, Lancaster, Stead, Mant und Fowler (2003) liegt die<br />
Abstinenzrate mit Hilfe des Kaugummis nach 1 Jahr bei ungefähr 18%.<br />
Das Nikotinpflaster ist ein selbstklebendes Hautpflaster mit Nikotin in der<br />
Klebeschicht. Eine Überdosierung kann mit hinreichender Sicherheit ausgeschlossen<br />
werden, da das Nikotin im Körper rasch eliminiert wird und Blutspiegelspitzen<br />
durch die kontinuierliche Abgabe vermieden werden. Ein<br />
Nachteil ist jedoch bei allen Pflastern die Tendenz des fallenden Nikotinlevels<br />
am späten Nachmittag. Die meisten Rückfälle passieren entsprechend<br />
am Abend, wenn die Pflaster am wenigsten Schutz bieten. In diesen Zeiten<br />
sollte ein Pflaster dringend mit einem schneller wirkenden Präparat (z.B.<br />
Kaugummi) kombiniert werden (Kornitzer, Boutsen, Dramaix, Thijs &<br />
Gustavsson, 1995). Metaanalysen ergaben nach sechs Monaten eine Abstinenzrate<br />
von circa 22% (Westman & Rose, 2000). In Kombination mit<br />
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Therapie der Nikotinabhängigkeit<br />
verhaltenstherapeutischen Programmen fand Huber (1992) eine Abstinenzrate<br />
von 26%.<br />
Das Nikotinnasenspray wird durch eine direkte Applikation des Nikotins<br />
auf die Nasenschleimhaut angewendet. Der Effekt nach sechs Monaten lag<br />
bei einer Abstinenzrate von 21% (Westman & Rose, 2000). In Deutschland<br />
wurde das Medikament jedoch wegen zu starker Nebenwirkungen wie Nasenirritationen,<br />
Tränenbildung, Niesen, Halsirritationen, laufender Nase,<br />
Husten, Kopfschmerzen, Schwindel, Herzklopfen, Schwitzen (Schneider,<br />
Olmstead, Mody, Doan, Franzon, Jarvik & Steinberg, 1995), bei 10-15%<br />
der Betroffenen auch Übelkeit und zu geringem Absatz 2003 vom Markt<br />
genommen und ist deswegen nur noch über das Internet erhältlich.<br />
Nikotininhalatoren sehen aus wie eine Plastikzigarette, die einen perforierten<br />
Kunststoffaufsatz enthält, der mit Nikotin getränkt ist. Der Inhalationsmechanismus<br />
ist derselbe wie bei der Zigarette (Schneider, Olmstead, Nilsson,<br />
Mody, Franzon & Doan, 1996). Man nimmt an, dass die sensorischen<br />
Sensationen in den Atemwegen, die beim Rauchen auftreten, imitiert werden<br />
und so das Craving weiter reduziert wird (Balfour & Fagerstrom, 1996;<br />
Pritchard, Robinson, Guy, Davis & Stiles, 1996). Die Abstinenzrate lag<br />
nach sechs Monaten bei 24% (Westman & Rose, 2000).<br />
Insgesamt kann bei Nikotinsubstitutionspräparaten wegen der langsamen<br />
Verbreitung des Nikotins im Körper und dem dadurch verzögerten Wirkungseintritt<br />
von einem geringen Abhängigkeitspotential ausgegangen werden<br />
(Hauffe, Imhof & Müller, 1989). Jedoch existieren auch Einzelfallberichte,<br />
in denen Anwender von Nikotinkaugummis abhängig geworden sind<br />
(Hughes, Hatsukami & Skoog, 1986; West & Russel, 1985). Nach aktuellem<br />
Stand werden die Raucher durch die nicht-vollständige Substitution des<br />
beim Rauchen erzielten Nikotinlevels durch alle Präparate unterdosiert, so<br />
dass das Auftreten von Entzugserscheinungen und Craving nach wie vor<br />
möglich ist. Eine Kombination einzelner Anwendungsformen, wie z.B. von<br />
Kaugummi und Pflaster, erhöht die Abstinenzraten auf 35%, was für eine<br />
Aufhebung des Unterdosierungseffekts sprechen könnte (Balfour & Fagerstrom,<br />
1996). Auch die Kombination mit Mecamlyamin als einem Niko-
Therapie der Nikotinabhängigkeit<br />
tinantagonisten, der die belohnenden Aspekte des Nikotins unterdrückt, hat<br />
sich in Kombination mit Substitutionspräparaten zur Abschwächung der<br />
Entzugserscheinungen in niedrigen Dosen mit einer Abstinenzrate von 40%<br />
nach sechs Monaten bewährt (Westman & Rose, 2000). Alle Substitutionspräparate<br />
sind in ihrer Effektivität und ihrem Nebenwirkungsprofil gut<br />
untersucht und gelten als pharmakologisches Mittel erster Wahl (Silagy et<br />
al., 2003).<br />
4.3.4. Vareniclin<br />
Vareniclin ist unter dem Handelsnamen Champix© eines der neuesten Medikamente,<br />
die gegen Nikotinabhängigkeit eingesetzt werden. Es handelt<br />
sich um einen Nikotinrezeptorpartialagonisten, das heißt er wirkt als Agonist<br />
über die Stimulation nikotinischer Acetylcholinrezeptoren gegen die<br />
Entzugssymptomatik inklusive des Cravings und reduziert als Antagonist<br />
der Suchtsubstanz gleichzeitig die Befriedigung durch das Rauchen (Rollema,<br />
Coe, Chambers, Hurst, Stahl & Williams, 2007). Die Wirkungen des<br />
Nikotins werden imitiert, indem eine moderate und anhaltende Dopaminausschüttung<br />
im mesolimbischen System hervorgerufen wird (Sands,<br />
Brooks, Chambers, Coe, Liu & Rollema, 2005). Parallel blockt es den Effekt<br />
einer nachfolgenden Dopaminausschüttung durch Nikotinzufuhr in<br />
Folge der Besetzung nikotinischer Acetylcholinrezeptoren und reduziert so<br />
die psychologische Belohnung bei denen, die trotz der Behandlung weiter<br />
rauchen. In der Theorie sollte die Kombination der beschriebenen beiden<br />
Wirkungen kurzfristig zu einer Reduktion des Rauchens führen. Es wird<br />
angenommen, dass über Monate hinweg so die Schlüsselreize, die mit den<br />
verstärkenden Wirkungen des Nikotins gekoppelt sind, in ihrer Wirkung<br />
gedämpft werden. In der Folge sollten die rauchassoziierten Verhaltensweisen<br />
leichter gelöscht werden, so dass eine Langzeitabstinenz möglich wird<br />
(Rollema et al., 2007). In der Praxis konnte Vareniclin die Effektivitätsrate<br />
gegenüber pharmakologisch nicht unterstützten Stopversuchen um das Dreifache<br />
erhöhen (Aveyard, 2006; Sands et al., 2005). Die Effektivität in der<br />
Rückfallprophylaxe ist jedoch bis heute nicht klar. Als wichtigste Nebenwirkung<br />
wurde eine leichte bis mittelstarke Übelkeit genannt, die mit der<br />
Zeit verschwand. Weiterhin wurden von Schlaflosigkeit, Kopfschmerzen,<br />
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Therapie der Nikotinabhängigkeit<br />
abnormen Träumen und einer zehnprozentigen Dropout-Rate berichtet. Die<br />
wenigen durchgeführten Studien ergaben eine gute Verträglichkeit nach<br />
zwölf Wochen Einnahme (Cahill, Stead & Lancaster, 2007; Foulds, 2006).<br />
Aveyard (2006) fand nach einem Jahr eine Abstinenzrate von 25%. Neuere<br />
Studien lieferten jedoch Hinweise darauf, dass Vareniclin suizidale und<br />
fremdaggressive Gedanken, sowie Stimmungsschwankungen auslösen<br />
könnte („Varenicline (Chantix) warnings: risk versus benefit“, 2008; „Varenicline:<br />
depression and suicide“, 2008).<br />
4.3.5. Rimonabant<br />
Rimonabant mit dem Handelsnamen Acomplia© ist der erste produzierte<br />
und klinisch getestete selektive Typ1-Cannabinoid-(CB1)-Rezeptor-<br />
Antagonist, der in der Raucherentwöhnung dabei helfen könnte, die Balance<br />
im endocannabinoiden System z.B. bezüglich der Kontrolle von Nahrungsaufnahme<br />
und des Energieausgleichs wieder herzustellen, das durch den<br />
länger anhaltenden Konsum von Nikotin gestört sein und das Nikotin- und<br />
Nahrungscraving bedingen könnte. Die zentralen Cannabinoid-(CB1)- Rezeptoren<br />
wurden, wie im Kapitel 3.2.2. beschrieben, erst vor kurzer Zeit mit<br />
Verstärkungsfunktionen im Gehirn in Zusammenhang gebracht und werden<br />
jetzt mit der Nahrungsaufnahme, mit Abhängigkeit und Habituation assoziiert<br />
(Castané, Berrendero & Maldonado, 2005). Wie man bei exzessivem<br />
Essen von einer Überaktivierung des endocannabinoiden Systems ausgeht,<br />
nimmt man auch bei wiederholter Nikotinzufuhr eine ähnliche Reaktion an.<br />
Auf diese Weise wirkt Rimonabant dem Widerstand vieler Raucher, wegen<br />
der befürchteten Gewichtszunahme nicht aufhören zu wollen, entgegen (Siu<br />
& Tindale, 2007). Bezüglich der Gewichtszunahme wurde im Vergleich zu<br />
einer Placebobedingung unter Rimonabant kurz- und langfristig nur ein<br />
moderater Anstieg unter den behandelten Rauchentwöhnern festgestellt<br />
(Cahill & Ussher, 2007). Die Bedeutung für die Rückfallprophylaxe ist<br />
bisher unklar. Durch den doppelten Ansatzpunkt des Medikaments an den<br />
zwei Hauptrisikofaktoren Rauchen und Fettleibigkeit für kardiovaskuläre<br />
Erkrankungen ist Rimonabant ein viel versprechendes klinisches Instrument.<br />
Jedoch liegen eine Reihe von Kontraindikationen vor, die den Einsatz<br />
deutlich einschränken. Als Nebenwirkungen waren vor allem Übelkeit und
Therapie der Nikotinabhängigkeit<br />
obere Atemwegsinfektionen zu beobachten, wobei deren Auftretenswahrscheinlichkeit<br />
als eher gering eingestuft wurde (Cahill & Ussher, 2007).<br />
Weitere geschilderte unbeabsichtigte Nebeneffekte, die bei der Gabe des<br />
Medikaments zur Gewichtsregulation in Erscheinung getreten waren, sind<br />
Müdigkeit, depressive Verstimmungen, Angst und Rhinopharyngitis.<br />
4.3.6. Pharmakologische Entwicklungsansätze<br />
Als neueste Entwicklung im Bereich der Raucherentwöhnung gelten Impfstoffe<br />
gegen Nikotin, die bisher die Phase der klinischen Testung noch nicht<br />
erreicht haben (Vocci & Chiang, 2001). Bisher geht man davon aus, dass sie<br />
bei drei Rauchertypen eine Reduktion des Rauchverhaltens erzielen könnten.<br />
Dazu zählen neben aktuellen Rauchern, die aufhören wollen, und Ex-<br />
Rauchern, die die Rückfallgefahr senken wollen, auch adoleszente Raucher,<br />
bei denen chronisches Rauchen verhindert werden soll. Da Nikotin der<br />
pharmakologische Agent ist, der die Rauchrate bestimmt, könnte eine Reduktion<br />
seiner Aufnahme ins Gehirn einen therapeutischen Nutzen bringen.<br />
Grundlage für eine erfolgreiche Wirkweise ist also die Fähigkeit eines<br />
Impfstoffes, Nikotin im extrazellulären Raum zu binden und dessen Aufnahme<br />
ins Gehirn zu verhindern oder zu reduzieren (Henningfield et al.,<br />
2005). Konsequenterweise könnten die neurobiologischen Phänomene abgeschwächt<br />
werden, die die Drogeneinnahme und –abhängigkeit aufrechterhalten,<br />
indem relevante pharmakokinetische Variablen (z.B. Geschwindigkeit<br />
oder Menge der Aufnahme ins Gehirn) entsprechend beeinflusst<br />
werden. Kriterien, die für klinische Impfstoffe erfüllt sein müssen, sind die<br />
Produktion einer ausreichend großen Menge von hochaffinen, nikotinspezifischen<br />
Antikörpern, um bereits bei den ersten Zügen des Zigarettenrauchens<br />
eine ausreichend große Menge des Suchtstoffes binden zu können<br />
und ein schnelles Bindungsverhalten, um die Menge des ins Gehirn eintretenden<br />
Nikotins auf ein subpharmakologisches Level zu reduzieren. Entsprechend<br />
ist die Hauptsorge in der Forschung, dass die Bindungskapazität<br />
der Antikörper, die durch die Impfung entstehen würden, limitiert und sättigbar<br />
ist, so dass der Raucher nach wiederholtem Rauchen den Effekt der<br />
Impfung rückgängig machen könnte. Obwohl die Entwicklung noch in den<br />
Kinderschuhen steckt, geht man bisher davon aus, dass ein Impfstoff gegen<br />
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Therapie der Nikotinabhängigkeit<br />
Nikotin mit relativ geringen Nebenwirkungen entwickelt (Fagerstrom,<br />
2003) und als Hilfe zur Raucherentwöhnung, als Rückfallprävention und als<br />
prophylaktisches Mittel eingesetzt werden kann. Den größten Effekt erwartet<br />
man sich dann bei Adoleszenten, weil viele Raucher in dieser Altersklasse<br />
(13 bis 18 Jahre) noch keine chronischen Raucher sind. Weitere Forschung<br />
wird zeigen müssen, ob sich diese Hoffnungen tatsächlich bestätigen.<br />
Weitere Substanzen, die sich noch in der Erforschung befinden, sich bisher<br />
aber in der Raucherentwöhnung noch nicht durchgesetzt haben, sollen hier<br />
nur der Vollständigkeit wegen erwähnt werden, um den Rahmen dieser<br />
Arbeit nicht zu sprengen. Dazu zählen Cholin und Substanz P, die über eine<br />
Inhibition der a7-Rezeptoren Einfluss auf die Nikotinwirkung zu nehmen<br />
scheinen (Cuevas & Adams, 2000). Auch Naltrexon, das über einen nichtkompetitiven<br />
Mechanismus in vitro a7-Rezeptoren auf Neuronen im Hippocampus<br />
blockiert und die Aktivität von a4b2-Rezeptoren reduzieren<br />
kann, wird auf seine mögliche Rolle bei der Raucherentwöhnung untersucht.<br />
Es scheint keinen Einfluss auf GABAerge oder NMDA-Rezeptoren<br />
zu haben (Almeida, Pereira, Alkondon, Fawcett, Randall Albuquerque,<br />
2000). So kommt es zu einer Vermehrung von a7-Rezeptoren, parallel wird<br />
die Zunahme von a4b2-Rezeptoren jedoch unterbunden. Schließlich haben<br />
auch endogene Steroide inhibitorische Wirkung gegenüber der Up-<br />
Regulation von a4b2-Rezeptoren. Progesteron z.B. beeinflusst die Acetylcholin-Rezeptoren<br />
mit a3-Proteinketten und solche vom a4b2-Rezeptortyp<br />
(Bullock, Clark, Grady, Robinson, Slobe, Marks & Collins, 1997). Ergänzend<br />
seien Antidepressiva und Serotoninwiederaufnahmehemmer (z.B.<br />
Fluoxetin) erwähnt, die sich in vitro als Inhibitoren der Nikotinrezeptorfunktion<br />
gezeigt haben (Fryer & Lucas, 1999).<br />
4.3.7. andere Behandlungsansätze<br />
Auch im Bereich heilpraktischer Therapiemethoden wurden verschiedene<br />
Interventionen zur Raucherentwöhnung eingesetzt. Dazu zählen neben der<br />
Akupunktur, der Akupressur, der Lasertherapie und der Elektrostimulation<br />
auch die Transkraniale Elektrotherapie, die auch neuroelektrische Therapie
Therapie der Nikotinabhängigkeit<br />
genannt wird. In einem Cochrane Review von White, Rampes und Campbell<br />
(2007) über die Effektivität dieser Methoden wurden 24 Studien eingeschlossen.<br />
Generell konnten keine durchgängigen Belege für ihre Effektivität<br />
entdeckt werden. Schließlich führen die Autoren eine potentielle Effektivität<br />
dieser Methoden auf die Ausschüttung von Neurotransmittern zurück,<br />
deren Wirkung nicht länger als 24 Stunden oder sogar weniger anhalten und<br />
deren Brauchbarkeit entsprechend limitieren würde. Crasilneck (1990) erreichte<br />
durch Hypnose angeblich eine Erfolgsquote von 81% Abstinenz<br />
nach einem Jahr. Er nahm die Sitzung auf Kassette auf, so dass die Klienten<br />
sie mit nach Hause nehmen und dort weiter üben konnten. Allerdings bestand<br />
sein Entwöhnungsprogramm auch aus unterstützenden Anrufen und<br />
einer Art sozialem Vertrag, so dass der Einfluss anderer Wirkfaktoren nicht<br />
ausgeschlossen werden kann. Zudem muss von einer selektiven Stichprobe<br />
ausgegangen werden, da nur wenige Menschen generell zu einer Hypnose<br />
bereit und dann auch noch ausreichend suggestibel sind.<br />
4.4. Zusammenfassende Bewertung bisheriger Therapieverfahren<br />
Nimmt man alle bisher dargestellten Interventionsmaßnahmen noch einmal<br />
in Augenschein, lässt es sich nicht leugnen, dass die Effektivitätsrate selbst<br />
bei kombiniertem Einsatz verschiedener Verfahren nicht als zufrieden stellend<br />
angesehen werden kann. Nur jeder Zweite bis Dritte Rauchentwöhner<br />
bleibt mindestens ein Jahr abstinent. Dies deutet darauf hin, dass eine kausale<br />
Therapie wegen der vielfältigen psychologischen Faktoren und der<br />
noch nicht ausreichend erforschten biologischen Prinzipien zum aktuellen<br />
Zeitpunkt noch nicht möglich ist. Die aktuell beste Lösung scheint deswegen<br />
dennoch eine Kombination von verhaltenstherapeutischen Programmen<br />
mit unterstützender Pharmakotherapie zu sein. Generell sollten dabei zuerst<br />
das Substitutionsprodukt oder das Medikament eingesetzt werden, um die<br />
Entzugssymptomatik zu reduzieren und dann in der Folge Selbstkontrolltechniken<br />
erlernt werden. Schließlich sollte nach drei bis sechs Monaten<br />
eine Wiederholungstherapie stattfinden, um die Effekte langfristig zu stabilisieren<br />
(Benowitz, 1993; Bents & Buchkremer, 1989; Hauffe et al., 1989;<br />
Stögbauer, Minneker & Buchkremer, 1989).<br />
87
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
5. Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
Im Bereich der Nikotinforschung wurden bildgebende Verfahren bisher nur<br />
sehr vereinzelt eingesetzt. In den folgenden Abschnitten sollen die Ergebnisse<br />
erster vorliegender Untersuchungen kurz dargestellt werden, da sie<br />
Hinweise auf an der Abhängigkeit beteiligte Hirnregionen geben können.<br />
5.1. EEG-Untersuchungen<br />
5.1.1. Kurzdarstellung des Verfahrens<br />
Bei der Ableitung von Elektroenzephalogrammen werden elektrische Potentialschwankungen<br />
in der Großhirnrinde registriert. Diese entstehen durch<br />
Aktionspotentiale in Axonen von Neuronen, durch Potentiale des Zellkörpers<br />
und der Dendriten, durch synaptische Potentiale oder durch postsynaptische<br />
Potentiale. Die EEG-Tätigkeit selbst wird durch die in Abhängigkeit<br />
vom Thalamus geregelte Synchronisation oder Desynchronisation der Potentiale<br />
hervorgerufen (Ebe & Homma, 1994). Die Elektroden werden auf<br />
der Kopfhaut angelegt. Gemessen werden die Potentialdifferenzen zwischen<br />
einer differenten und einer Bezugselektrode gemessen. Letztere wird auch<br />
als indifferente Elektrode bezeichnet, da sie sich möglichst weit von den<br />
interessierenden Regionen entfernt befindet. Dabei handelt es sich in den<br />
meisten Untersuchungen um eine Position am Ohrläppchen. Dadurch sind<br />
Amplitudenvergleiche zwischen den einzelnen Ableitepunkten möglich.<br />
Was im EEG zu sehen ist sind Informationen, die vom Kortex an andere<br />
Hirnstrukturen weitergegeben werden. Die elektrische Aktivität an der<br />
Schädeloberfläche schwankt zwischen 1 und 100 mV. Es handelt sich um<br />
ein sehr schwaches Signal, weswegen eine kontinuierliche Verstärkung<br />
durch einen Differenzverstärker erfolgen muss. In regelmäßigen Zeitabständen,<br />
meist 100mal pro Sekunde, wird ein Wert durch einen Analog-Digital-<br />
Wandler ausgelesen und an den Computer weitergeleitet, der aus den Einzeldaten<br />
einen Potentialverlauf rekonstruieren kann. Um zu verhindern, dass<br />
physiologisch irrelevante Frequenzen außerhalb von 0 bis 50 Hz mit erfasst<br />
89
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Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
werden, werden so genannte Tief-Pass- und Hoch-Pass-Filter eingesetzt.<br />
Diese dienen auch zur Eliminierung sehr langsamer Veränderungen im<br />
EEG, die meist nicht biologischen Ursprungs sind, sondern auf Veränderungen<br />
im elektrischen System zwischen Kopfhaut, Elektrodengel und Elektrode<br />
zurückzuführen sind.<br />
Bei akustischer, visueller oder somatosensorischer Reizung peripherer Rezeptoren<br />
treten reizabhängig geringe Potentialschwankungen mit verschiedenen<br />
Latenzen im EEG auf. Diese werden als evozierte oder ereigniskorrelierte<br />
Potentiale bezeichnet. Die Elektroden werden bei dieser Messmethode<br />
meist nach dem 10-20-Elektrodensystem (Jasper, 1958) platziert, wobei sie<br />
beidseits symmetrisch in gleichen Abständen angebracht werden und bei<br />
Erwachsenen circa fünf bis sieben Zentimeter voneinander entfernt liegen.<br />
Die Bezeichnungen der Positionen stimmen dabei mit den anatomischen<br />
Begriffen überein (z.B. Pz = parietal zentral). Ereigniskorrelierte Potentiale<br />
sind prinzipiell in der Lage, auch tiefer im Gehirn liegende Aktivitäten<br />
abzubilden, sie nehmen jedoch mit der Tiefe in ihrer Intensität ab.<br />
Der größte Teil der chemosensorisch evozierten Potentiale besteht aus einer<br />
großen negativen Komponente, die meistens als N1 bezeichnet wird. Diese<br />
tritt normalerweise 320 bis 450ms nach Applikation des Reizes auf. Dieser<br />
Komponente folgt ein großer positiver Ausschlag, der den Namen P2 trägt<br />
und 530 bis 800ms nach Stimulusbeginn sichtbar wird. Eine frühe Komponente<br />
P1 wurde manchmal als erstes positives Maximum zwischen 250 und<br />
320ms beschrieben, sie ist jedoch weniger konsistent ableitbar. Die Amplitude<br />
der drei Komponenten wird von verschiedenen Faktoren beeinflusst.<br />
Trigeminale Reize lösen in der Regel größere Potentiale aus als olfaktorische.<br />
Die Amplitude von N1 liegt gewöhnlich zwischen 3-10mV, die von P2<br />
zwischen 5 und 20mV. Der Vergleich von Latenzzeiten olfaktorischer und<br />
trigeminaler Reize ergab uneinheitliche Ergebnisse (Rombaux, Mouraux,<br />
Bertrand, Guerit & Hummel, 2006).<br />
Von der frühen Komponente P1 wird angenommen, dass sie vorwiegend<br />
exogene kortikale Aktivierungen widerspiegelt, die direkt mit den Reizeigenschaften<br />
(z.B. Intensität) in Zusammenhang stehen und nur gering durch
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
psychologische Variablen, Aufmerksamkeitsprozesse oder organismische<br />
Zustände wie z.B. Schlaf beeinflusst werden (Donchin, Ritter & McCallum,<br />
1978). Die späte P2-Komponente, sowie noch spätere, für diese Arbeit nicht<br />
relevante Parameter reflektieren hingegen endogene kortikale Aktivität, die<br />
die Neuheit und die Bedeutung des sensorischen Ereignisses widerspiegelt<br />
und von physikalischen Reizeigenschaften unabhängig ist (Evans, Cui &<br />
Starr, 1995; Knott, 1991). Diese Einteilung ist jedoch stark vereinfacht, da<br />
nur die ganz frühen Potentiale rein exogen sind. Bereits nach 50 Millisekunden<br />
muss von einem zusätzlichen endogenen Anteil ausgegangen werden.<br />
Möglicherweise könnten Unterschiede in der Größe der endogenen<br />
Komponente zwischen olfaktorischen und trigeminalen Reizen auf deren<br />
Verschiedenartigkeit von normalen Gerüchen zurückzuführen sein (Rombaux<br />
et al., 2006).<br />
5.1.2. relevante Voruntersuchungen mit EEG<br />
Kobal und Hummel (1988, 1991, 1994) und Livermore et al. (1992) fanden<br />
heraus, dass die Amplituden N1/P2, welche die Differenz zwischen den<br />
beiden ersten Extrema im Potential widerspiegeln, bei olfaktorischen Reizen<br />
bei Pz und Cz, also zentral und parietal am größten ausfielen, bei chemosensorischen<br />
Potentialen dagegen eher zentral. Außerdem konnten sie<br />
beobachten, dass bei steigernder trigeminaler Konzentration die Latenzzeiten<br />
immer geringer wurden, während die Amplituden zunahmen. Die Intensitätseinschätzungen<br />
der Probanden korrelierten dabei signifikant mit den<br />
geschilderten Potentialeigenschaften. Auch bei olfaktorischen Potentialen<br />
waren die Abnahme der Amplituden und die Zunahme der Latenzzeiten<br />
signifikant mit den subjektiven Ratings korreliert. Eine Verlängerung der<br />
Latenzzeit P2, also bis zum zweiten Maximum, konnte mit der Verarbeitung<br />
unangenehmer Reize in Verbindung gebracht werden. Je unangenehmer der<br />
Reiz, desto größer war die Latenz. Weiterhin stellten die Autoren fest, dass<br />
die Amplituden bei mehrfacher trigeminaler Stimulation bei Cz abnehmen,<br />
während die Latenzzeiten sich nicht änderten. Um eine ähnliche Habituation<br />
bei olfaktorischen Reizen zu verhindern, muss das Intervall zwischen den<br />
applizierten Reizen, das Interstimulusintervall, mindestens 30 Sekunden<br />
betragen.<br />
91
92<br />
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
Rombaux et al. (2006) stellten in ihrer Untersuchung fest, dass ein Anstieg<br />
der Geruchskonzentration auch einen Anstieg der Amplitude nach sich zog.<br />
Außerdem nahmen die Latenzzeiten deutlich ab. Um maximale Amplituden<br />
ableiten zu können, empfehlen die Autoren ein Interstimulusintervall von<br />
40-50 Sekunden. Es konnten keine weiteren Zuwächse mit steigendem<br />
zeitlichem Abstand mehr erzielt werden. Sie berichten zudem von einer<br />
Lateralisierung in der rechten Hemisphäre, die sie durch mögliche Erinnerungseffekte<br />
und emotionale Prozesse erklären. Zusätzlich weisen sie auf<br />
die Notwendigkeit einer konstanten Vigilanz während der Aufnahme hin,<br />
die durch eine leichte kognitive Aufgabe gewährleistet werden kann, die der<br />
Proband parallel zur Reizapplikation ausführen soll.<br />
Die Arbeitsgruppe von Tateyama et al. (1998) konnte ebenfalls ansteigende<br />
Amplituden und sinkende Latenzzeiten feststellen, wobei diese Effekte am<br />
deutlichsten für die Gipfel P1 und N1 ausfielen. Vorher bestimmte Schwellen<br />
korrelierten mit den gemessenen Latenzzeiten, jedoch nicht mit den<br />
Amplituden.<br />
Oloffson und Nordin (2004) stellten Geschlechtsunterschiede in der wahrgenommenen<br />
Intensität fest, die sich in der signal-to-noise-ratio in den<br />
individuellen trigeminalen evozierten Potentialen widerspiegelten. Bei<br />
Frauen konnten frühe Komponenten (P1, N1) leichter identifiziert werden.<br />
Späte positive Komponenten (P2/P3) zeigten bei allen Elektrodenableitungspunkten<br />
eine größere Amplitude und bei Cz eine geringere Latenzzeit<br />
für das weibliche Geschlecht.<br />
5.2. PET-Untersuchungen<br />
5.2.1. Kurzdarstellung des Verfahrens<br />
In den meisten PET-Untersuchungen werden den Probanden kleine Mengen<br />
radioaktiver Wassermoleküle als Marker injiziert. PET-Kameras registrieren<br />
durch die von diesem Marker ausgesendeten Positronen Veränderungen<br />
im regionalen zerebralen Blutfluss. Weil diese mit neuraler Aktivität einhergehen,<br />
können die Daten Informationen über dynamische Veränderun-
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
gen im Gehirn liefern. Vorteile dieser Untersuchungsart sind, dass das komplette<br />
Gehirn simultan untersucht werden kann und anders als in fMRT-<br />
Studien Aufnahmen des ventralen Temporal- und des Frontallappens nicht<br />
durch Artefakte belastet sind. Ein Nachteil dieser Methode ist unter anderem<br />
die geringe räumliche Auflösung. Durch die Unschärfe der Aufnahmen<br />
können Foki, die weniger als 10-12mm auseinander liegen, nicht unterschieden<br />
werden. Außerdem ist die zeitliche Auflösung von der Halbwertszeit<br />
des Markes abhängig. Generell werden die Daten in Scanperioden von<br />
60-90 Sekunden erhoben und die Aufgaben sind in Blockdesigns angeordnet,<br />
so dass jede Injektion des Markers mit einem Aufgabenblock korrespondiert.<br />
Dieses große Zeitfenster könnte die Detektion von Arealen verhindern,<br />
die nur zu Beginn olfaktorischer Stimulation aktiviert sind (z.B.<br />
Areale, die schnell habituieren). Zusätzlich muss die Anzahl der Scans in<br />
jeder Untersuchung auf 8-16 begrenzt werden, um die radioaktive Exposition<br />
der Probanden in Grenzen zu halten (Weismann, Yousry, Heuberger,<br />
Nolte, Ilmberger, Kobal, Yousry, Kettenmann & Naidich, 2001).<br />
5.2.2. relevante Voruntersuchungen<br />
Brody, Mandelkern, Lee, Smith, Sadeghi, Saxena, Jarvik und London<br />
(2004) und Brody et al. (2002) beobachteten in PET-Studien, dass die Exposition<br />
von unbehandelten Rauchern mit rauchassoziierten Reizen in einer<br />
regionalen hirnmetabolischen Aktivierung des perigenualen/ventral anterioren<br />
cingulären Kortex (ACC) resultierte. Gleichzeitig stellten sie auch positive<br />
Korrelationen zwischen der Intensität des Zigarettencravings und dem<br />
relativen Glucosemetabolismus im orbitofrontalen Kortex, dem dorsolateralen<br />
präfrontalen Kortex und der anterioren Insula fest. Im Vergleich zu<br />
Rauchern, die mit Bupropion behandelt wurden, reagierten unbehandelte<br />
Raucher auf rauchassoziierte Reize mit einer signifikant größeren Aktivierung<br />
im anterioren cingulären Kortex. Die gleiche Arbeitsgruppe fand bei<br />
Rauchern im Entzug ein größeres Bindungspotential im ventralen Striatum<br />
und im linken ventralen Putamen (Brody et al., 2004). Zubieta, Heitzeg, Xu,<br />
Koeppe, Ni, Guthrie und Domino (2005) fanden in einem ähnlichen Untersuchungsdesign<br />
Abnahmen des regionalen cerebralen Blutflusses im anterioren<br />
Cingulum, im präfrontalen Cortex, im Nucleus accumbens und im<br />
93
94<br />
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
rechten Hippocampus, sowie eine bilaterale Reduktion in der Amygdala.<br />
Rose, Behm, Westman und Bates (2003) entdeckten außerdem, dass bei<br />
Rauchern die Gabe des Nikotinantagonisten Mecamylamin den regionalen<br />
cerebralen Blutfluss im ventralen Striatum, dem präfrontalen Cortex, der<br />
Amygdala und dem anterioren Cingulum, dessen Anstieg nach der Präsentation<br />
rauchassoziierter Reize zu beobachten ist, vermindert.<br />
5.3. fMRT-Untersuchungen<br />
5.3.1. Kurzdarstellung des Verfahrens<br />
Die funktionelle Magnetresonanztomographie, kurz fMRT ist ein Echtzeit-<br />
Bildgebungsverfahren und ermöglicht die nicht-invasive Untersuchung<br />
menschlicher Gehirnaktivität durch die Messung lokalisierter, intrinsischer<br />
Signalveränderungen. Sie misst Umverteilungen in der relativen Proportion<br />
von oxygeniertem und deoxygeniertem Blut (Spinelli, Lazeyras, Willi,<br />
Slosman, Delavelle, Seeck & Michel, 2003). Diese treten auf, wenn in einer<br />
Hirnregion eine gestiegene neurale Aktivität einen Anstieg des Blutflusses<br />
hervorruft (Braus, Brassen, Weimer & Tost, 2003). Gegenüber den PET-<br />
Untersuchungen gibt es eine Reihe von Vorteilen. So ist es z.B. ein kostengünstigeres<br />
und leichter zugängliches Verfahren. Durch den Verzicht auf<br />
radioaktive Marker können die Probanden auch mehrfach gescannt werden.<br />
Die räumliche Auflösung des fMRT übersteigt typischerweise auch die des<br />
PET. Um jedoch Gruppenanalysen durchführen zu können, müssen die<br />
individuellen Daten in stereotaktische Koordinaten überführt werden. Um<br />
die normale Restvarianz in der funktionellen Anatomie zwischen den Personen<br />
kompensieren zu können, die teilweise bis zu 10-15mm betragen<br />
kann, müssen im Gegensatz zu PET-Datenanalysen zusätzliche räumliche<br />
Korrekturen vorgenommen werden. Ein weiterer Vorteil dieses Verfahrens<br />
ist, dass für die Aufzeichnung des kompletten Gehirnvolumens die zeitliche<br />
Auflösung auf bis zu vier Sekunden gesteigert werden kann (Braus et al.,<br />
2003). Typischerweise setzt sich das fMRT-Signal ein bis zwei Sekunden<br />
nach Beginn der neuralen Aktivität vom Grundrauschen ab und erreicht<br />
nach ungefähr acht Sekunden ein Plateau. Der größte Nachteil von fMRT-<br />
Untersuchungen sind die in ventralen frontalen und temporalen Gehirnregi-
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
onen häufig auftretenden Artefakte. Die sich dort befindenden Knochen und<br />
die Luft produzierenden Feldinhomogenitäten können zu Signalausfällen<br />
oder –verzerrungen führen. Derartige Störungen können die Auswertung<br />
von Bildern dieser Regionen schwierig oder sogar unmöglich machen. Obwohl<br />
inzwischen eine Reihe von Strategien entwickelt wurden, bleiben<br />
Areale wie der orbitofrontale Kortex in vielen Studien unmessbar (Weismann<br />
et al., 2001).<br />
5.3.2. relevante Voruntersuchungen<br />
Stein (2001) und Stein, Pankiewicz, Harsch, Cho, Fuller, Hoffman, Hawkins,<br />
Rao, Bandettini und Bloom (1998) untersuchten akute Effekte im<br />
zentralen Nervensystem nach der Gabe von Nikotin bei 16 aktiven Rauchern<br />
und fanden einen dosisabhängigen Anstieg der neuronalen Aktivität<br />
in der Insula, im Frontallappen, im Nucleus accumbens, der Amygdala, dem<br />
anterioren Cingulum, im Hypothalamus und im limbischen Thalamus Da<br />
der Frontallappen zahlreiche dopaminerge Innervationen aufweist und der<br />
cinguläre Kortex zahlreiche Verbindungen zu neokortikalen, motorischen<br />
und sensorischen Arealen unterhält, wurde angenommen, dass diese beiden<br />
Regionen in verschiedene kognitive Bereiche, wie z.B. das Arbeitsgedächtnis,<br />
Aufmerksamkeit, Motivation, Stimmung und Emotion, involviert sind.<br />
Zusätzlich finden sich nikotinische Rezeptoren auch auf somatodendritischen<br />
und auf Axonverbindungen des Locus Coeruleus noradrenerger Neuronen<br />
(Mitchell, 1993). Von ihnen ist bekannt, dass sie zum Vorderhirn und<br />
zum Hippocampus projizieren, denen eine entscheidende Rolle in der Regulation<br />
und Modulation der Erregung und der Aufmerksamkeit zugesprochen<br />
wird (Aston-Jones, Rajkowski, Kubiak & Alexinsky, 1994).<br />
Durch visuelle Schlüsselreize hervorgerufenes Craving korrelierte bei Rauchern<br />
im Gegensatz zu Nichtrauchern eher mit der Aktivierung des ventralen<br />
anterioren Cingulum, des superioren frontalen Gyrus, des ventralen<br />
Striatums bzw. des Nucleus accumbens und der Amygdala (David, Munafo,<br />
Johansen-Berg, Smith, Rogers, Matthews & Walton, 2005; McClernon,<br />
Hiott, Huettel & Rose, 2005). Die Erwartung, Rauchen zu dürfen, führte zu<br />
einer veränderten Aktivierung frontaler Regionen, die in PET-und fMRT-<br />
95
96<br />
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
Studien ebenfalls mit Craving in Verbindung gebracht wurden (Brody et al.,<br />
2002; Maas, Lukas, Kaufman, Weis, Daniels, Rogers, Kukes & Renshaw,<br />
1998). Auch der dorsolaterale präfrontale und der orbitofrontale Kortex<br />
präsentierten sich als beeinflussbar durch Erwartungseffekte (Wilson, Sayette,<br />
Delgado & Fiez, 2005). McBride, Barrett, Kelly, Aw und Dagher<br />
(2006) fanden keine Hirnaktivierungen auf Schlüsselreize, wenn die Probanden<br />
wussten, dass sie nicht rauchen dürfen, während im anderen Fall<br />
Aktivierungen in Regionen auftraten, die mit Erregung (z.B. Thalamus,<br />
Cingulum), Aufmerksamkeit (z.B. anteriores Cingulum) und kognitiver<br />
Kontrolle (z.B. dorsolateraler präfrontaler Kortex) in Verbindung gebracht<br />
werden.<br />
Due, Huettel, Hall und Rubin (2002) fanden in einer Untersuchung bei<br />
Rauchern im Entzug nach der Darbietung von rauchassoziierten Bildern ein<br />
größeres fMRT-Signal im mesolimbischen dopaminergen Belohnungssystem<br />
als nach neutralen Reizen. Dabei waren vor allem die rechte posteriore<br />
Amygdala, der posteriore Hippocampus, das ventrale Tegmentum und der<br />
mediale Thalamus aktiviert. Außerdem stellten sie eine erhöhte Aktivierung<br />
in der visuospatialen Aufmerksamkeit, das heißt im bilateralen präfrontalen<br />
und parietalen Kortex, sowie im rechten fusiformen Gyrus fest. Auch im<br />
Vergleich zu einer Nichtrauchergruppe waren die Aktivierungen signifikant<br />
größer. Obwohl keine direkte Applikation von Nikotin erfolgte, wurden die<br />
gleichen aktivierten Areale inklusive der Andeutung einer reduzierten Aktivität<br />
im Nucleus accumbens wie bei tatsächlichem Konsum der Substanz<br />
deutlich. Dadurch wird die Annahme gestützt, dass bereits konditionierte<br />
Reize das Belohnungssystem stimulieren können (Pagnoni, Zink, Montague<br />
& Berns, 2002). David et al. (2007) fanden zudem in einer fMRT-<br />
Untersuchung an Frauen heraus, dass die Aktivierung des Nucleus accumbens<br />
bzw. des ventralen Striatums bei Rauchern, die sich nicht im Entzug<br />
befanden, im Vergleich zu abstinenten Teilnehmern größer war. Weiterhin<br />
waren die Aktivierungen im entzügigen Zustand in der linken Hemisphäre<br />
größer, während bei gewöhnlichem Rauchverhalten ein entgegen gesetztes<br />
Muster zu beobachten war.
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
McClernon, Hiott, Liu, Salley, Behm und Rose (2007) fanden in einer Untersuchung<br />
an Rauchern heraus, dass ein löschungsorientiertes Raucherentwöhnungsprogramm<br />
die Antworten des Gehirns auf rauchassoziierte Reize<br />
verändern kann und dass diese Veränderungen mit einer positiven Behandlungsprognose<br />
zusammenhängen könnten. Bei allen Teilnehmern traten<br />
Veränderungen in der Amygdala auf, Unterschiede im Thalamus wurden<br />
jedoch nur bei Rauchern festgestellt, die eine einmonatige Abstinenz erreichten.<br />
Naqvi, Rudrauf, Damasio und Bechara (2007) und Gray und<br />
Critchley (2007) stellten fest, dass Raucher mit einer Schädigung der Insula<br />
signifikant leichter mit dem Rauchen aufhören konnten und nicht mehr<br />
rückfällig wurden, da nach dem Rauchstop kein Verlangen nach dem Nikotin<br />
mehr aufgetreten war.<br />
In einer erst kürzlich von Albrecht, Kopietz, Linn, Sakar, Anzinger, Schreder,<br />
Pollatos, Brückmann, Kobal und Wiesmann (2008) durchgeführten<br />
fMRT-Studie konnten nach intranasaler Stimulation mit Nikotin Aktivierungen<br />
im piriformen Kortex, im frontalen Kortex, im cingulären Kortex, in<br />
der Insula und im supramarginalen Kortex festgestellt werden. Zusätzlich zu<br />
den Gehirnregionen, die mit olfaktorischen Prozessen in Verbindung gebracht<br />
werden, wurde auch in Verarbeitungszentren trigeminaler Reize<br />
Aktivität detektiert. Dazu zählen der Thalamus, der subzentrale Gyrus und<br />
der sekundäre somatosensorische Kortex (SII). Die Autoren gehen deswegen<br />
davon aus, dass eine vollständige Separation olfaktorischer und trigeminaler<br />
Effekte durch Reduktion der Nikotinkonzentration in verabreichten<br />
Reizen nicht möglich ist. Sogar bei der Verabreichung schwellennaher<br />
Konzentrationen werden trigeminale Areale mit aktiviert.<br />
5.4. Zusammenfassende Bewertung<br />
Die dargestellten bildgebenden Verfahren konnten demonstrieren, dass<br />
Raucher nach der Konfrontation mit rauchassoziierten Reizen eine erhöhte<br />
Aktivierung in Gehirnregionen aufweisen, die mit Aufmerksamkeit (z.B.<br />
anteriores Cingulum, Thalamus), Emotion (z.B. Amygdala), Belohnung<br />
(z.B. Nucleus accumbens) und Motivation (z. B. präfrontaler und orbitofrontaler<br />
Kortex) in Verbindung gebracht werden (Brody et al., 2002;<br />
97
98<br />
Voruntersuchungen im Bereich der Nikotinabhängigkeit<br />
Cerf-Ducastel & Murphy, 2001; David et al., 2005; Domino, Minoshima,<br />
Guthrie, Ohl, Ni, Koeppe & Zubieta, 2000; Domino, Ni, Xu, Koeppe, Guthrie<br />
& Zubieta, 2004, Due et al., 2002; Gottfried, Deichmann, Winston &<br />
Dolan, 2002; McClernon et al., 2007; Poellinger, Thomas, Lio, Lee, Makris,<br />
Rosen & Kwong, 2001; Volkow, Fowler & Wang, 2004; Wiesmann, Kopietz,<br />
Albrecht, Linn, Reime, Kara, Pollatos, Sakar, Anzinger, Fesl et al.,<br />
2006; Yousem, Williams, Howard, Andrew, Simmons, Allin, Geckle,<br />
Suskind, Bullmore, Brammer et al., 1997). Dabei reagieren typische sekundäre<br />
und tertiäre olfaktorische Regionen wie der orbitofrontale und der<br />
piriforme Kortex, das Cingulum, die Insula, die Amygdala und der Hippocampus<br />
(Anderson et al., 2003; Cerf-Ducastel & Murphy, 2001, 2004; Gottfried<br />
et al., 2002; Poellinger et al., 2001; Savic, 2002; Wiesmann, Kettenmann<br />
& Kobal, 2004). Angenehme Duftstoffe scheinen mediale Regionen<br />
des orbitofrontalen Kortex zu aktivieren, während unangenehme Duftstoffe<br />
eher laterale Regionen desselben Hirnbereichs ansprechen (Anderson et al.,<br />
2003; Gottfried et al., 2002; Rolls, Kringelbach & de Araujo, 2003).<br />
Gleichzeitig wurden aber auch Aktivierungen in Hirnarealen gefunden, die<br />
für die Verarbeitung trigeminaler Reize zuständig sind. Dazu gehören der<br />
Thalamus, der Gyrus subcentralis/sekundärer somatosensorischer Kortex,<br />
der Gyrus präcentralis und der Gyrus postcentralis (Boyle et al., 2007; Hari,<br />
Portin, Kettenmann, Jousmäki & Kobal, 1997; Hummel et al., 2005; Kettenmann<br />
Jousmaki, Portin, Salmelin, Kobal & Hari, 1996; Savic, Gulyas &<br />
Berglund, 2002; Yousem et al., 1997). Craving scheint vor allem mit den<br />
Hirnstrukturen der Amygdala, des Nucleus accumbens, des Thalamus, des<br />
Hippocampus und dem anterioren Cingulum (Besson et al., 2007; Due et<br />
al., 2002; McClernon et al., 2005; McClernon et al., 2007) in Verbindung zu<br />
stehen.
6. Die Untersuchung<br />
Die Untersuchung<br />
Wie im Theorieteil dieser Arbeit vorgestellt, wurden bereits einige Versuche<br />
unternommen, Hirnareale zu identifizieren, die an der Verarbeitung der<br />
Wahrnehmung von Nikotin, Konditionierungsprozessen und dem Craving<br />
beteiligt sind. Dabei unterschieden sich die Ansätze hinsichtlich ihrer Vorgehensweisen<br />
und eingesetzten Methoden sehr stark. Bei der Messung evozierter<br />
Potentiale wurden meist nur visuelle Schlüsselreize wie zum Beispiel<br />
das Foto einer rauchenden Zigarette eingesetzt. In anderen Studien wurde<br />
die Substanz injiziert, um pharmakologische Wirkungen untersuchen zu<br />
können. Ziel dieser Studie war es, intranasale Reize zu nutzen, um die sensorischen<br />
Wirkungen des Nikotins zu untersuchen. Dabei sollten mehrere<br />
bildgebende Untersuchungsmethoden mit möglichst identischem Untersuchungsdesign<br />
angewandt und die resultierenden Ergebnisse integriert werden,<br />
was soweit der Autorin bekannt, bisher nicht geschehen ist. Für die<br />
beiden Untersuchungsmethoden der funktionellen Magnetresonanztomographie<br />
und der Elektroenzephalographie erfolgte eine differenzielle Auswertung<br />
für die Gruppen Raucher, Raucher im Entzug und Nichtraucher.<br />
Die Messungen nach Reizung mit beiden Nikotinstereoisomeren erlaubte<br />
die Untersuchung des Einflusses der Rauchervorgeschichte, da nur S-<br />
Nikotin in der Zigarette enthalten ist und somit den Rauchern bekannt ist.<br />
Das Verständnis für die der Nikotinabhängigkeit zugrunde liegenden Mechanismen<br />
sollte dadurch weiter verbessert und eine mögliche Grundlage<br />
für die Entwicklung effektiverer Behandlungsansätze geliefert werden.<br />
Das Untersuchungsdesign wurde so entworfen, dass nach der Eingangsuntersuchung<br />
zur Prüfung der Einschlusskriterien zunächst Untersuchungen<br />
mit dem Elektroenzephalogramm durchgeführt wurden. Anschließend erfolgten<br />
die Messungen mit der funktionellen Magnetresonanztomographie.<br />
Teilnehmende Raucher bildeten die Experimentalgruppe, wobei sie unter<br />
typischem Konsumverhalten und im Entzug gemessen wurden.<br />
Nichtraucher, die als Kontrollgruppe fungierten, durchliefen die angegebenen<br />
Untersuchungen ebenfalls. Jedoch unterschieden sie sich von der Expe-<br />
99
100<br />
Die Untersuchung<br />
rimentalgruppe neben dem Rauchstatus insofern, als jeweils nur eine einmalige<br />
Messung für sie vorgesehen war.<br />
Die zentralen Fragestellungen dieser Untersuchung lauteten demnach:<br />
1. Welche Komponenten des Gehirns sind für die Nikotinwahrnehmung<br />
und dessen hedonische Einschätzung von herausragender Bedeutung?<br />
2. Welche Strukturen sind an Konditionierungsprozessen bezüglich des<br />
Rauchens beteiligt?<br />
3. Lassen sich spezielle Strukturen identifizieren, die für stimulusinduziertes<br />
Craving verantwortlich sind?<br />
Mit der vorliegenden Untersuchung soll ein weiterer Schritt in Richtung der<br />
Beantwortung dieser Fragen erfolgen, um für Folgearbeiten eine differenziertere<br />
Grundlage zu liefern.<br />
6.1. Überblick über den Untersuchungsablauf<br />
Der Ablauf dieses Studienprogramms wird aus Abbildung 9 ersichtlich. Die<br />
verschiedenen Farben geben an, welche Bausteine mit der gleichen Untersuchungsmethode<br />
durchgeführt wurden. Die einzelnen Untersuchungen<br />
fanden jeweils an unterschiedlichen Tagen statt.
Nichtraucher<br />
Ableitung evozierter<br />
Potentiale (EEG)<br />
Ableitung evozierter<br />
Potentiale (fMRT)<br />
Die Untersuchung<br />
Eingangsuntersuchung<br />
Ableitung evozierter<br />
Potentiale (EEG) bei<br />
normalem Zigarettenkonsum<br />
Ableitung evozierter<br />
Potentiale (EEG)im<br />
Zustand nach 3 Tagen<br />
Entzug<br />
Ableitung evozierter<br />
Potentiale (fMRT) bei<br />
normalem Zigarettenkonsum<br />
Ableitung evozierter<br />
Potentiale (fMRT) im<br />
Zustand nach 3 Tagen<br />
Entzug<br />
Abbildung 9: Überblick über den Untersuchungsablauf<br />
Raucher<br />
101
102<br />
Die Untersuchung<br />
6.2. Untersuchungsinstrumente<br />
6.2.1. Olfaktometer<br />
Das Gesamtsystem des Olfaktometers wird durch einen Behälter mit Raumluft<br />
mit einer Flussrate von 8 l/min geleitet, die mit Hilfe von Massenflussmessern<br />
angezeigt und kontrolliert werden kann. Die Luft wird in diesem<br />
Behälter auf 80% Luftfeuchtigkeit angereichert, indem der Strom durch<br />
destilliertes Wasser mit konstanter Temperatur geleitet wird. Um eine Kondensation<br />
während des Transports zu vermeiden, wird das Gasgemisch bzw.<br />
die Raumluft durch eine Ummantelung mit einem zweiten Wasserkreislauf<br />
kontinuierlich geheizt. Der Kanal, der die Luft zum Nasenloch des Probanden<br />
befördert, wird durch ein Heizband mit elektrischem Widerstand erwärmt,<br />
um die Temperatur des Stroms im Moment des Austritts aus dem<br />
Teflonrohr der Nase anzupassen (36,5°C). Das Ende dieses Verbindungsstücks<br />
wird mit Hilfe eines Nasenadapters während der vollständigen Messung<br />
im Nasenloch des Probanden platziert. In Abbildung 10 ist das Olfaktometer<br />
des Typs OM4 (Firma Burghart Messtechnik GmbH, Wedel,<br />
Deutschland) abgebildet, das während der EEG-Untersuchung eingesetzt<br />
wurde.<br />
Abbildung 10: Bei der EEG-Untersuchung eingesetztes Olfaktometer
Die Untersuchung<br />
Auch die Flussrate am Endstück beträgt durchgehend 8 l/min. In den Interstimulusintervallen,<br />
in denen kein Duftstoff zur Nase geleitet wird, fließt<br />
der so genannte Hauptluftstrom zum Probanden. Bei jeder Stimuluspräsentation<br />
öffnet sich ein Paar elektromagnetischer Ventile für die Dauer von<br />
250ms, in denen der Hauptluftstrom durch ein identisches Volumen des mit<br />
Raumluft angereicherten Duftstoffs ersetzt wird. Beide Luftströme fließen<br />
mit gleich bleibendem Volumen von 8 l/min. Während der Interstimulusintervalle<br />
wird der mit dem Geruch angereicherte Luftfluss durch ein Vakuum<br />
abgesaugt und aus dem System entfernt. Nach dem Öffnen der Ventile während<br />
der Stimuluspräsentation wird wiederum der Hauptluftstrom aus dem<br />
Kreislauf geleitet. So kann die Flussrate in der Nase sowohl während, als<br />
auch zwischen den Stimulationsperioden konstant gehalten werden. Alle<br />
Flussraten wurden regelmäßig mit Hilfe eines Gilibrators überprüft und<br />
gegebenenfalls neu kalibriert. Die EEG-Aufzeichnungen wurden 500 Millisekunden<br />
vor Öffnung der Luftstromventile durch ein Trigger-Signal gestartet.<br />
Mit einer zeitlichen Konstanz von 30ms Verzögerung verlässt der Geruch<br />
den Transportschlauch und erreicht die Nase des Probanden. Eine<br />
schematische Darstellung des eben geschilderten Funktionsprinzips des<br />
Olfaktometers findet sich in Abbildung 11.<br />
103
104<br />
Die Untersuchung<br />
Abbildung 11: Funktionsprinzip des Olfaktometers 8<br />
Um auch die Flussrate in der Nase konstant zu halten und so Intensitätsunterschiede<br />
in der Wahrnehmung zu vermeiden (Kobal, van Toller & Hummel,<br />
1989), wurde mit den Teilnehmern velopharyngeales Atmen geübt.<br />
Dies bedeutet, dass die Probanden mit Hilfe eines Blatt Papiers unter der<br />
Nase trainiert wurden, durch den Mund zu atmen. Bei der Atmung durch die<br />
Nase hätte sonst die Gefahr des Schnüffelns bestanden, das auch in der<br />
Absenz olfaktorischer Reize zu Aktivierungen im piriformen, im entorhinalen<br />
und parahippocampalen Kortex führt und die Auswertungen verfälscht<br />
hätte (Anderson et al., 2003). Wenn das Ziel erreicht war, reliabel durch den<br />
Mund zu atmen ohne das Blatt Papier in Bewegung zu versetzen, wurde mit<br />
der Messung begonnen. Alle Reize wurden ausschließlich in das rechte<br />
Nasenloch appliziert, da in Abhängigkeit von der stimulierten Seite unterschiedliche<br />
Aktivierungsmuster gefunden wurden (Frasnelli, Heilmann &<br />
8 aus Burghart Messtechnik GmbH, 2008
Die Untersuchung<br />
Hummel, 2004; Thuerauf, Gossler, Lunkenheimer, Lunkenheimer, Maihöfner,<br />
Bleich, Kornhuber, Markovic & Reulbach, 2008).<br />
6.2.2. Elektroenzephalogramm<br />
Die EEG-Aktivität wurde mit Hilfe von aktiven nicht-polarisierten<br />
Ag/AgCl-Elektroden an Fz, Cz und Pz (Mittellinie), sowie C3 und C4 am<br />
Temporallappen nach dem 10/20-System mit den Bezugselektroden A1 und<br />
A2 an beiden Ohrläppchen (linked earlobes) abgeleitet. Geerdet wurden die<br />
Teilnehmer über drei Erdungselektroden am processus mastoideus, wobei<br />
auf der rechten Seite zwei und an der linken Seite eine angebracht wurden.<br />
Zusätzlich wurde die elektrookulare Aktivität mit Hilfe einer Elektrode<br />
(Fp2) beobachtet, die über dem rechten Auge angebracht war. Die EEG-<br />
Aktivität wurde für jeden applizierten Reiz für jeweils 1024ms nach analoger<br />
Filterung (Bandpassfilter mit einem Bereich von 0.2-70 Hertz) abgeleitet<br />
und mit einem Analog-Digital-Wandler digitalisiert. Die Aufzeichnung<br />
begann jeweils 500ms vor dem Stimulusbeginn. Der Mittelwert dieser<br />
Prästimulusphase diente als Baseline für die Amplitudenbestimmung.<br />
Kobal und Hummel (1991) betonen für EEG-Untersuchungen die Notwendigkeit,<br />
die abgeleiteten Potentiale durch Mittlung (averaging) bei geeigneter<br />
Filterung von der Hintergrundaktivität zu trennen. Die stationären chemosensorisch<br />
evozierten Potentiale heben sich durch die Mittelung von<br />
zehn bis dreißig artefaktfreien EEG-Ableitungen von der Hintergrundaktivität<br />
ab. Höhere Stimuluskonzentrationen, aber auch große und unvorhersagbare<br />
Interstimulusintervalle ergeben Potentiale größeren Ausmaßes. Von<br />
der Größe ihrer Amplituden wird angenommen, dass sie die Anzahl neuronaler<br />
Ressourcen widerspiegeln, die durch einen neuralen Prozess in Anspruch<br />
genommen werden. Die Latenzzeit, mit der sie auftreten, wird mit<br />
der Geschwindigkeit in Verbindung gebracht, mit der der Reiz verarbeitet<br />
wird. Evozierte Potentiale haben eine hohe, in der Größenordnung von<br />
Millisekunden angesiedelte zeitliche, jedoch eine geringe räumliche Auflösung<br />
(Rombaux et al., 2006). Zur Durchführung von Mittelungen müssen<br />
die applizierten Reize identisch replizierbar sein, das heißt es darf keine<br />
Varianzen in Latenzzeiten oder Fluktuationen in Stimuluskonzentrationen<br />
105
106<br />
Die Untersuchung<br />
geben. Außerdem muss der Stimulusonset weniger als 50ms betragen (Murphy,<br />
Nordin, de Wijk, Cain & Polich, 1994), damit die gleichzeitige Aktivierung<br />
einer ausreichenden Menge kortikaler Neuronen garantiert ist. Parallel<br />
darf keine mechanische oder thermische Reizung entstehen, da sonst<br />
die EEG-Antwort nicht mehr den einzelnen Reizaspekten zugeordnet werden<br />
kann. Auch die Atmung muss kontrolliert werden, um eine standardisierte<br />
Verarbeitung der Reize unabhängig von der Ein- und Ausatmung<br />
gewährleisten zu können. Deswegen wird den Probanden, wie oben beschrieben,<br />
die Technik des velopharyngealen Verschlusses beigebracht, bei<br />
der sie während der gesamten Messung durch den Mund atmen (Kobal &<br />
Hummel, 1988).<br />
6.2.3. Funktionelle Magnetresonanztomographie<br />
Für die Aufzeichnung der funktionellen Bilder wurde ein 3-Tesla-<br />
Magnetresonanztomograph Trio der Firma Siemens Vision (Erlangen) eingesetzt.<br />
Es wurde echoplanare Bildgebung (EPI) mit einer T2*-gewichteten<br />
Multischichtgradientenechosequenz [Echozeit (TE) = 30 ms, Repetitionszeit<br />
(TR) = 3000 ms, Voxelgröße 80 x 224 x 2 mm, Matrixgröße 672 x 672]<br />
verwendet. Mit Hilfe einer localizer-Serie wurde die Positionierung des<br />
Probanden vorgenommen, die den Kopf in den drei Raumebenen abbildet.<br />
Das Schichtpaket wurde parallel zur Interkommissurallinie, auch AC/PC-<br />
Linie genannt, die auf einem sagittalen Localizer-Bild eingezeichnet wurde,<br />
ausgerichtet. Im Anschluss wurden je 40 funktionelle halbkoronare Schichten<br />
(2,3 mm dick), die das Gehirn und die Augen des Probanden weitgehend<br />
vollständig abdeckten, aufgenommen. Mit Hilfe einer Reihe von Probemessungen<br />
wurden die verwendeten Parameter (TE, Kippung der Schichten,<br />
Schichtdicke) für die Aufzeichnung intranasal erzeugter evozierter Potentiale<br />
optimiert. Die abgestimmte Triggerung des Magnetresonanztomographen<br />
und des Olfaktometers erfolgte manuell. Das Olfaktometer wurde nach der<br />
dritten Messeinheit gestartet.<br />
Die einzelnen Scanningserien bestanden aus 310 (olfaktorisch) bzw. 250<br />
Bildern (trigeminal) Gesamtvolumen, so dass in einer fMRT-Sitzung insgesamt<br />
560 Bilder entstanden. Nach der Komplettierung der zwei funktionel-
Die Untersuchung<br />
len Durchgänge wurde eine T1-gewichtete strukturelle MP-Rage mit den<br />
gleichen Parametern, die bei den fMRT-Sequenzen eingesetzt wurden, gefahren.<br />
6.3. Eingesetzte Substanzen<br />
6.3.1. Nikotinenantiomere<br />
Zur Gewährleistung einer standardisierten Applikation der beiden Nikotinenantiomere<br />
als eigentliche Testsubstanzen mussten optisch und chemisch<br />
pures S- und R-Nikotin von Dr. C. Marks im Chemischen Laboratorium<br />
Worms mit der gleichen Methode hergestellt werden. Destilliertes R-<br />
Nikotin wurde aus zu 98% chemisch purem S-Nikotin der Firma Aldrich<br />
anhand von Racemisierung und nachfolgende Separation des R-Nikotins<br />
durch Kristallisierung mit (R, R)-Weinsäure und di-p-toloyl-(S, S)-<br />
Weinsäure erzeugt. S-Nikotin wurde aus 98% chemisch purem S-Nikotin<br />
der Firma Aldrich mit Hilfe von Racemisierung und nachfolgende Separation<br />
des S-Nikotins durch Kristallisierung mit (S, S)-Weinsäure und di-ptoloyl-(R,<br />
R)-Weinsäure hergestellt. Beide Endprodukte wurden in Glasröhrchen<br />
in reiner Stickstoffatmosphäre bei -60°C aufbewahrt bis die Experimente<br />
stattfanden. Die optische Reinheit lag bei mehr als 99%.<br />
6.3.2. Kontrollsubstanzen CO2 und Phenylethylalkohol<br />
Wie Doty, Brugger, Jurs, Orndorff, Snyder und Lowry (1978) in einer Untersuchung<br />
mit anosmischen und normosmischen Probanden feststellen<br />
konnten, haben die Mehrzahl der in Studien verwendeten Gerüche sowohl<br />
eine trigeminale als auch eine olfaktorische Komponente. Lediglich Phenylethylalkohol,<br />
Schwefelwasserstoff und Vanillin konnten von anosmischen<br />
Patienten, die zwar auf trigeminale, nicht aber auf olfaktorische Stimulation<br />
reagieren, nicht identifiziert werden. Es kann also davon ausgegangen werden,<br />
dass die genannten Substanzen in niedriger und mittlerer Konzentration<br />
ausschließlich das olfaktorische System aktivieren. Entsprechend wurde als<br />
olfaktorischer Kontrollreiz Phenylethylalkohol eingesetzt. Der Geruch dieser<br />
Substanz ähnelt dem Duft einer Rose.<br />
107
108<br />
Die Untersuchung<br />
Als rein trigeminale Substanz hatte sich in mehreren Untersuchungen CO2<br />
erwiesen (z.B. Kobal & Hummel, 1988). Eine Aktivierung olfaktorischer<br />
Komponenten kann demnach ausgeschlossen werden, so dass es als trigeminaler<br />
Kontrollreiz in dieser Studie eingesetzt werden konnte.<br />
6.4. Daten und Datenquellen 9<br />
Wie aus Abbildung 8 ersichtlich, stützte sich die vorliegende Untersuchung<br />
im Wesentlichen auf zwei Arten von Daten: die EEG-Daten und die fMRT-<br />
Daten. Zusätzlich wurden während aller Untersuchungen verschiedene<br />
Psychophysikdaten erhoben. Im Folgenden wird detaillierter dargestellt,<br />
welche Quellen jeweils verwendet wurden.<br />
EEG-Daten:<br />
Aus den Aufnahmen mit Hilfe des Elektroenzephalogramms resultierten<br />
zwei verschiedene Arten von Informationen, die für olfaktorische und trigeminale<br />
Reize und die einzelnen Untersuchungsgruppen getrennt erfasst<br />
wurden. Zum einen lieferten die evozierten Potentiale Daten zu den maximalen<br />
Amplituden P1, N1 und P2, die in Kapitel 5.1.1. bereits näher beschrieben<br />
wurden. Diese Werte lagen für jeden der abgeleiteten Kanäle Fz,<br />
Cz, Pz, C3 und C4 vor. Diese wurden sowohl als peak-to-peak-Amplituden,<br />
welche die Distanz zwischen zwei Extrema widerspiegeln, als auch als<br />
base-to-peak-Amplituden, die den Abstand jeder einzelnen der Komponenten<br />
von der Baseline darstellen, ausgewertet.<br />
Des Weiteren konnten durch die evozierten Potentiale auch die Größe der<br />
Latenzzeiten zu den Extrema P1, N1 und P2 berechnet werden, indem von<br />
der Gesamtaufnahmezeit die Prästimulusphase von 512 Millisekunden abgezogen<br />
wurde. Auch diese Werte lagen für alle abgeleiteten Elektrodenpositionen<br />
vor.<br />
9 Die einzelnen Fragebögen und Auswertungen finden sich im Anhang dieser Arbeit.
fMRT-Daten:<br />
Die Untersuchung<br />
Für die zeitlich getrennt stattfindenden olfaktorischen und trigeminalen<br />
Sequenzen lagen für jeden Probanden individuelle Aktivierungsmuster nach<br />
erfolgter Stimulation vor. Die funktionellen Daten wurden mit den anatomischen<br />
Aufnahmen zu einem dreidimensionalen Muster integriert und mit<br />
Hilfe der Talairach-Koordinaten in ein „Standardgehirn“ transformiert (eine<br />
detaillierte Beschreibung erfolgt in Kap. 6.8.3). So konnten die Daten der<br />
Einzelprobanden zu einer Multi-Study zusammengefasst werden und die<br />
Aktivierungen, die nicht probandenspezifisch, sondern verallgemeinerbar<br />
nach nasalen Reizen auftreten, interpretiert werden. Diese Muster lagen für<br />
die genannten Sequenzen für jede einzelne Reizklasse getrennt vor.<br />
Psychophysikdaten:<br />
Sowohl während der Aufzeichnung des Elektroenzephalogramms als auch<br />
während der funktionellen Magnetresonanztomographie wurden die Probanden<br />
gebeten, jeden applizierten Reiz mit Hilfe einer visuellen analogen<br />
Ratingskala hinsichtlich verschiedener Qualitäten zu bewerten. Abbildung<br />
12 zeigt die speziell für die beiden Untersuchungsmodalitäten entwickelten<br />
Systeme, in die die Teilnehmer vor Beginn der Messung ausführlich eingewiesen<br />
wurden. Folgende Parameter wurden dabei erhoben: Intensität des<br />
Geruchs, Intensität des Brennens, Intensität des Stechens und Verlangen zu<br />
Rauchen/Craving mit jeweils 0 als minimaler und 100 als maximaler Intensität,<br />
sowie Hedonik mit 0 als maximal unangenehmer, 50 als neutraler und<br />
100 als maximal angenehmer Bewertung.<br />
109
110<br />
Die Untersuchung<br />
Abbildung 12: Ratingverfahren der EEG-Untersuchung (links) und der funktionellen Magnet-<br />
resonanztomographie (rechts)<br />
Außerdem wurden zu Beginn per Fragebogen und Fagerström-Test einige<br />
demographische Variablen und das Rauchverhalten erhoben, anhand derer<br />
die Aufteilung in die Untersuchungsgruppen stattfand. Bei Rauchern und<br />
Rauchern im Entzug erfolgten außerdem ein Bluttest bezüglich des Cotinin-<br />
bzw. Nikotingehalts und die Messung des Kohlenmonoxidgehalts in der<br />
Atemluft mittels Smokerlyzer der Firma Bedfont (Kent, England), um den<br />
Entzugsstatus verifizieren zu können.<br />
6.5. Hypothesen<br />
Ziel der Studie war es herauszufinden, ob sich Raucher, Raucher im Entzug<br />
und Nichtraucher hinsichtlich ihrer Reaktion auf verschiedene Nikotin- und<br />
Kontrollreize unterscheiden. Aus den am Anfang dieses Kapitels dargestellten<br />
Fragestellungen ergaben sich für diese Arbeit folgende Hypothesen:<br />
Die unter Nikotin, CO2 und Phenylethylalkohol auftretenden neuronalen<br />
Aktivitäten in der Elektroenzephalographie bzw. Aktivierungsmuster<br />
in der funktionellen Magnetresonanztomographie entsprechen<br />
den Ergebnissen aus bekannten Voruntersuchungen.<br />
Nichtraucher, Raucher und Raucher im Entzug unterscheiden sich<br />
im Hinblick auf die Amplitudengröße und die Latenzzeiten der<br />
EEG-Komponenten P1, N1 und P2.
Die Untersuchung<br />
Im EEG weisen Nichtraucher, Raucher und Raucher im Entzug<br />
keine Lateralisierungstendenzen auf. Die Frontalisierungstendenz<br />
ist für trigeminale Reize stärker ausgeprägt.<br />
Im fMRT zeigen Raucher und Nichtraucher aufgrund unterschiedlicher<br />
Vorerfahrungen in Folge der Applikation von S-Nikotin<br />
voneinander abweichende Aktivierungsmuster. Dabei werden vor<br />
allem Unterschiede in der Amygdala, im präfrontalen Kortex, im<br />
anterioren Cingulum, in der Insula, im ventralen Striatum, im somatosensorischen<br />
Kortex I und II, im Thalamus und im Hippocampus<br />
bzw. dem parahippocampalen Kortex erwartet.<br />
Raucher und Raucher im Entzug zeigen im Vergleich zu Nichtrauchern<br />
aufgrund ihrer Lerngeschichte ausgeprägte Unterschiede in<br />
der Wahrnehmung von S- und R-Nikotin in der Amygdala, im<br />
präfrontalen Kortex, im anterioren Cingulum, im ventralen Striatum,<br />
im Thalamus, in der Insula und im Hippocampus bzw. im parahippocampalen<br />
Gyrus.<br />
Die auf S-Nikotin folgenden Aktivierungen bei Rauchern im Entzug<br />
sind aufgrund der Abstinenzbedingung in der Amygdala, im<br />
Nucleus accumbens, im Thalamus, im Hippocampus, in der Insula<br />
und im präfrontalen Kortex stärker ausgeprägt als bei Rauchern.<br />
Insgesamt bewerten Nichtraucher die Nikotinenantiomere negativer<br />
als die beiden anderen Untersuchungsgruppen.<br />
Die genaue Durchführung der Untersuchung zur Überprüfung dieser Hypothesen<br />
mit einer Beschreibung der Stichproben und des Ablaufs der einzelnen<br />
Sitzungen wird in den folgenden Kapiteln vorgestellt.<br />
6.6. Eingangsuntersuchung<br />
Alle Teilnehmer der Studie durchliefen zunächst eine eineinhalbstündige<br />
Untersuchung zu Beginn, bei der geprüft wurde, ob sie die Eingangsvoraussetzungen<br />
erfüllten. Zunächst erhielten sie eine ausführliche Probandeninformation,<br />
in der sie über mögliche Nebenwirkungen, sowie Ziel und Ablauf<br />
der Studie informiert wurden (s. Anhang I). Im Anschluss unterschrieben<br />
alle eine Einverständniserklärung für die Teilnahme an der Studie und<br />
111
112<br />
Die Untersuchung<br />
die notwendigen Blutentnahmen. Zudem wurden sie darüber informiert, zu<br />
jedem Zeitpunkt der Studie ohne Angabe von Gründen die Teilnahme beenden<br />
zu können.<br />
Die allgemeinen Einschlusskriterien für die Untersuchung waren für alle<br />
Teilnehmer identisch, sofern sie sich nicht auf das Rauchverhalten bezogen.<br />
Gründe für den Ausschluss aus der Studie waren fehlende Volljährigkeit,<br />
Riechstörungen, relevante psychische, psychiatrische oder körperliche Erkrankungen,<br />
bei Frauen Schwangerschaft und Stillzeit und die Einnahme<br />
von Medikamenten außer Kontrazeptiva. Für die Experimentalgruppe galt<br />
zusätzlich das Kriterium, seit mindestens zwei Jahren mehr als 20 Zigaretten<br />
am Tag zu rauchen und unter einer Nikotinabhängigkeit nach ICD-10 zu<br />
leiden. Zur Charakterisierung des Konsumverhaltens wurde wie bereits<br />
erwähnt der Fagerström-Test eingesetzt. In der Kontrollgruppe durfte kein<br />
regelmäßiger Tabakkonsum zu irgendeinem Zeitpunkt vorgelegen haben,<br />
außerdem mussten die letzten beiden Jahre vollständig rauchfrei gewesen<br />
sein. Durch die beiden letztgenannten Bedingungen konnte zusätzlich die<br />
Grundlage für einen Extremgruppenvergleich und damit für aussagekräftigere<br />
Ergebnisse geschaffen werden. Diese Daten wurden vornehmlich in<br />
einem Interview erhoben.<br />
Körperliche Erkrankungen wurden zusätzlich durch eine Kontrolle von<br />
Standardwerten des Blutbildes und eine ärztliche Untersuchung ausgeschlossen.<br />
Wurden Medikamente eingenommen, erfolgte die Einschätzung<br />
der Relevanz für diese Studie durch einen erfahrenen Pharmakologen.<br />
Speziell für die funktionelle Magnetresonanztomographie wurde außerdem<br />
im Rahmen eines Interviews ausgeschlossen, dass die Probanden unter<br />
relevanten Angststörungen litten oder Metallimplantate (z.B. künstliche<br />
Gelenke, Herzschrittmacher) vorhanden waren. Wegen der möglichen<br />
Auswirkungen auf Stillzeit und Schwangerschaft wurde letztere durch einen<br />
Urintest ausgeschlossen und durch die Frage nach wirksamer Verhütung<br />
während der Untersuchung kontrolliert.
Die Untersuchung<br />
Das Vorliegen einer normalen Geruchsfähigkeit wurde zusätzlich mit Hilfe<br />
des Sniffin´Sticks Test (Burghart Messtechnik GmbH, Wedel, Deutschland)<br />
untersucht. Bei diesem Test werden verschiedene Gerüche mit Hilfe von<br />
Stiften dargeboten, die mit unterschiedlichen Substanzen gefüllt sind (siehe<br />
Abbildung 13). Er besteht aus drei Teilen, die die Geruchsschwelle, die<br />
Geruchsdiskrimination und die Geruchsidentifikation messen. Zur näheren<br />
Darstellung des Verfahrens sei auf Hummel, Sekinger, Wolf, Pauli und<br />
Kobal (1997) verwiesen.<br />
Abbildung 13: Aufbau des Sniffin´Sticks Test (© by Firma Burghart Messtechnik GmbH)<br />
Vor jeder Untersuchungssitzung wurden die Probanden außerdem gebeten,<br />
mindestens sechs Stunden zu schlafen und zwölf Stunden vor Beginn keinen<br />
Alkohol mehr zu sich zu nehmen, um Artefakte in der Bildgebung zu<br />
vermeiden. Zudem wurde nach Infektionskrankheiten und akuter Medikamenteneinnahme<br />
gefragt.<br />
113
114<br />
6.7. EEG-Untersuchung<br />
Die Untersuchung<br />
6.7.1. Stichprobe der EEG-Untersuchung<br />
Eingeschlossen wurden insgesamt 30 studentische Versuchspersonen der<br />
Friedrich-Alexander-Universität Erlangen/Nürnberg, wobei 15 der Probanden<br />
sowohl der Untersuchungsgruppe Raucher als auch der Untersuchungsgruppe<br />
Raucher im Entzug angehörten. Das Alter der Probanden variierte<br />
zwischen 20 und 28, der Durchschnitt lag bei 24,03 Jahren. Insgesamt nahmen<br />
14 männliche und 16 weibliche Personen an der Untersuchung teil. Die<br />
Stichprobe bestand vorwiegend aus Medizinstudenten und wurde durch<br />
Interessierte aus anderen Studienfächern ergänzt.<br />
Als Kriterium für die Stichprobengleichheit diente neben der Geschlechtsaufteilung<br />
auch das Alter:<br />
In beiden Untersuchungsgruppen befanden sich jeweils 8 weibliche<br />
und 7 männliche Versuchspersonen. So konnte der Einfluss von<br />
Geschlechtsunterschieden in der hedonischen (Perkins, et al.,<br />
2001), nozizeptiven (Jamner et al., 1998) und chemosensorischen<br />
(Oloffson & Nordin, 2004; Stuck, Frey, Freiburg, Hörmann, Zahnert<br />
& Hummel, 2006) Wahrnehmung als konfundierender Variable<br />
weitgehend kontrolliert werden.<br />
Das Alter variierte in der Experimentalgruppe zwischen 20 und 28,<br />
der Altersdurchschnitt lag bei 23,87 Jahren. In der Kontrollgruppe<br />
lag der Range zwischen 20 und 27, der Durchschnitt bei 24,13 Jahren.<br />
Der Unterschied war nicht signifikant.<br />
6.7.2. Darstellung des Untersuchungsablaufs der EEG-Untersuchung<br />
Während der Messungen saßen die Probanden in einem klimatisierten, gut<br />
belüfteten Raum und ihre Bewegungen wurden über einen Videokontrollmonitor<br />
beobachtet. Außerdem trugen sie Kopfhörer, über die sie weißes<br />
Rauschen mit ungefähr 50dB Schalldruckpegel hörten, um Geräusche, die<br />
durch das Umschalten des Stimulators entstanden, zu maskieren. Sie wurden<br />
gebeten, ihren Kopf und ihre Augen möglichst wenig zu bewegen und
Die Untersuchung<br />
nicht zu blinzeln. Um ihre Vigilanz zu stabilisieren, lösten die Teilnehmer<br />
parallel zur Messung eine Verfolgungsaufgabe. Ein kleiner Punkt musste<br />
mit Hilfe eines Joysticks in einem größeren Quadrat gehalten werden, das<br />
sich unberechenbar auf dem Bildschirm bewegte.<br />
Jede EEG-Sitzung bestand aus einer Schwellenbestimmung, einer olfaktorischen<br />
und einer trigeminalen Sequenz. Die Schwellenbestimmung erfolgte<br />
nach dem Algorithmus von Wysocki und Beauchamp (1984). Zunächst<br />
wurden die olfaktorischen Schwellen für S- und R-Nikotin bestimmt. Danach<br />
schloss sich für beide Substanzen die Erfassung der Brenn- und Stechschwellen<br />
an. Für die Bestimmung selbst wurden jedem Probanden Reizkombinationen<br />
in aufsteigender Geruchskonzentration appliziert, wobei die<br />
zu Beginn dargebotene jeweils deutlich unter der individuellen Riechschwelle<br />
lag. Jede Reizkomposition bestand aus einem Triplett von zwei<br />
Luftreizen und einem Zielstimulus, die in randomisierter Reihenfolge dargeboten<br />
wurden. Eine Bestimmungsserie wurde beendet, wenn dreimal in<br />
aufeinander folgenden Konzentrationen für den Zielreiz eine klare Sensation<br />
berichtet werden konnte, während die Darbietung der Kontrollstimuli<br />
ohne berichtete Wahrnehmung blieb. Das Triplett mit der geringsten objektiven<br />
Geruchsintensität wurde als Schwelle angenommen. Eine klare Sensation<br />
wurde als eine eindeutige olfaktorische, brennende oder stechende<br />
Wahrnehmung definiert. Die Stimulusdauer betrug jeweils 250 Millisekunden,<br />
das Interstimulusintervall betrug 90 Sekunden.<br />
Die sich anschließende olfaktorische Sequenz bestand jeweils aus zwölf S-<br />
und R-Nikotinreizen, die in Anlehnung an die durchgeführte Schwellenbestimmung<br />
in jeweils individueller Konzentration dargeboten wurden. Der<br />
olfaktorische Zusammensetzung errechnete sich dabei nach folgender Formel:<br />
[Trigeminale Schwelle S-Nikotin – olfaktorische Schwelle S-Nikotin] x 0,3<br />
+ olfaktorische Schwelle S-(-Nikotin)<br />
Der als Kontrollreiz eingesetzte Rosengeruch mit einer Konzentration von<br />
2,4 l/min wurde ebenfalls zwölf Mal angeboten Alle Geruchsreize wurden<br />
115
116<br />
Die Untersuchung<br />
in pseudorandomisierter Reihenfolge appliziert, um Interaktionseffekte<br />
zwischen den einzelnen Reizklassen ausschließen zu können. Die trigeminale<br />
Serie bestand ebenfalls aus jeweils zwölf in pseudorandomisierter<br />
Abfolge verabreichten S- und R-Nikotinreizen in einer Konzentration von 8<br />
l/min. Als Kontrollreiz wurde hier Kohlenstoffdioxid mit einem Fluss von<br />
4,8 l/min eingesetzt. Alle applizierten Stimuli dauerten 250ms. Zur Vermeidung<br />
von Habituationseffekten wurde mit einem Interstimulusintervall von<br />
90s gearbeitet. Die Abfolge der Reize erfolgte wiederum pseudorandomisiert.<br />
Die Anzahl der Reize in den jeweiligen Sequenzen reichte aus, um ein<br />
akzeptables Signal-Rausch-Verhältnis zu erzielen. Zusätzlich sollte durch<br />
das große Stimulusintervall eine mögliche Ansammlung von Nikotin an der<br />
nasalen Mucosa und eine potentielle zeitliche Summation an den Rezeptoren<br />
verhindert werden. In den olfaktorischen Sequenzen konnte so die Möglichkeit<br />
des Auftretens trigeminaler Effekte minimiert werden (Cometto-<br />
Muniz, Cain & Abraham, 2004). Jede EEG-Untersuchung bestand somit aus<br />
insgesamt 72 Geruchsreizen. Die Abfolge der Reize in der olfaktorischen<br />
und trigeminalen Sequenz kann der Tabelle 1 entnommen werden.
Die Untersuchung<br />
olfaktorisch trigeminal<br />
Rose CO2<br />
Rose S-Nikotin<br />
R-Nikotin CO2<br />
S-Nikotin R-Nikotin<br />
R-Nikotin S-Nikotin<br />
R-Nikotin S-Nikotin<br />
S-Nikotin R-Nikotin<br />
S-Nikotin CO2<br />
Rose S-Nikotin<br />
R-Nikotin R-Nikotin<br />
Rose R-Nikotin<br />
S-Nikotin CO2<br />
Rose CO2<br />
R-Nikotin S-Nikotin<br />
R-Nikotin S-Nikotin<br />
S-Nikotin CO2<br />
S-Nikotin R-Nikotin<br />
R-Nikotin CO2<br />
Rose R-Nikotin<br />
S-Nikotin R-Nikotin<br />
R-Nikotin S-Nikotin<br />
Rose R-Nikotin<br />
Rose S-Nikotin<br />
S-Nikotin CO2<br />
S-Nikotin CO2<br />
R-Nikotin S-Nikotin<br />
R-Nikotin S-Nikotin<br />
Rose R-Nikotin<br />
Rose R-Nikotin<br />
R-Nikotin CO2<br />
R-Nikotin R-Nikotin<br />
S-Nikotin R-Nikotin<br />
S-Nikotin S-Nikotin<br />
Rose S-Nikotin<br />
S-Nikotin CO2<br />
Rose CO2<br />
Tabelle 1: Abfolge der Reize in der olfaktorischen und trigeminalen Sequenz in der EEG-<br />
Untersuchung<br />
Zusätzlich zu den EEG-Daten wurden für jeden applizierten Reiz mit Hilfe<br />
einer elektronischen visuellen Analogskala verschiedene psychophysische<br />
Daten erhoben, die durch Unterbrechung des Verfolgungsspiels auf dem<br />
117
118<br />
Die Untersuchung<br />
Monitor eingeblendet wurden. Dabei sollten die Intensität der Reize, die<br />
Hedonik und das aktuelle Verlangen zu Rauchen (Craving) eingeschätzt<br />
werden. Für die trigeminalen Reize wurde zusätzlich die Intensität des<br />
Brennens und Stechens erhoben.<br />
Zur Kontrolle der Angaben der Raucher über die Menge der gerauchten<br />
Zigaretten wurden zum Einen Kohlenmonoxydanalysen in der ausgeatmeten<br />
Luft durchgeführt, wobei ab einem Wert von 4ppm von Nichtrauchern,<br />
bzw. in der Experimentalgruppe von tatsächlichem dreitägigem Entzug<br />
ausgegangen wurde. Zum Zweiten wurde von den Teilnehmern der Raucher-<br />
und der Entzugsbedingung vor jeder Untersuchung eine Blutprobe<br />
entnommen, die hinsichtlich des Cotiningehalts untersucht wurde.<br />
6.7.3. Auswertung der EEG-Daten<br />
Die Auswertung der Datensätze aus der EEG-Untersuchung erfolgte mit<br />
Hilfe des Programms EPevaluate 4.2.1. (Firma Burghart Messtechnik<br />
GmbH, Wedel, Deutschland). Generell stellen Störeinflüsse, die nicht durch<br />
das Gehirn produziert werden, bei dieser Art von Ableitung ein mögliches<br />
Problem dar. Neben hoher Varianzen, die durch die Verwendung verschiedener<br />
Elektrodenarten, Gelsorten und unterschiedliche Kopfhautbeschaffenheiten<br />
entstehen, kann es auch zu veränderten elektrochemischen Eigenschaften<br />
durch Schwitzen kommen (Picton, Lins & Scherg, 1995). Dies<br />
wurde durch eine Klimatisierung des Untersuchungsraums zu verhindern<br />
versucht. Bewegungen der Augen und Lidschläge, die ebenfalls zu Artefakten<br />
führen können, wurden durch die Ausführung der beschriebenen Verfolgungsaufgabe<br />
und die Anweisung, so wenig wie möglich zu zwinkern,<br />
weitgehend unterbunden. Da sich diese Störquelle jedoch auf diesem Weg<br />
nicht vollständig eliminieren lässt, wurden die Einzelableitungen über alle<br />
Reizklassen und Ableitungskanäle mit Hilfe der parallel erfassten elektrookularen<br />
Aktivität auf derartige Artefakte untersucht und durch Zwinkern<br />
verfälschte Potentiale aus der Auswertung ausgeschlossen. Einzelpotentiale,<br />
bei denen ein Bewegungsartefakt oder eine Muskelaktivität ersichtlich war,<br />
wurden ebenfalls nicht berücksichtigt. Diese werden außerdem frequenzabhängig<br />
zum Teil bereits durch den Tief-Pass-Filter eliminiert. Weitere Arte-
Die Untersuchung<br />
fakte, die nicht ereigniskorreliert sind, werden durch den folgenden Prozess<br />
der Mittelung weitgehend ausgeschlossen, wobei der Signal-Rausch-<br />
Abstand auch von der Anzahl der zu verarbeitenden Einzelableitungen<br />
(Wiederholungen) abhängt. Deswegen wurde darauf geachtet, dass für jeden<br />
Probanden in der Regel nicht mehr als ein Drittel der Potentiale von der<br />
Auswertung ausgeschlossen werden musste.<br />
Der Mittelungsprozess erfolgte über die bereits beschriebenen gleich großen<br />
Zeitphasen nach Applikation des Reizes für jede Reizklasse getrennt. Dadurch<br />
wurden wie bereits erwähnt die Störeinflüsse weitgehend eliminiert<br />
und der Signal-Rausch-Abstand durch die Verminderung des Hintergrundrauschens<br />
des Spontan-EEGs im Mittelungsprozess verbessert. Nur so wird<br />
es überhaupt möglich, die ereigniskorrelierten Potentiale auszuwerten. Das<br />
Ergebnis wird als Grand-Average bezeichnet und spiegelt die elektrokortikale<br />
Antwort wider, die ein durchschnittliches Gehirn auf den applizierten<br />
Reiz zeigt.<br />
Die gemittelten Daten wurden hinsichtlich verschiedener Aspekte ausgewertet.<br />
So wurden zunächst die Amplituden P1, N1 und P2 von erfahrenen<br />
Auswertern identifiziert und mit Hilfe zugehöriger Kennzeichnungslinien<br />
im Programm festgelegt. Dabei wurden die maximalen Werte eines Potentialverlaufs<br />
in einem zeitlich sinnvollen Fenster gesucht. Die Differenzen<br />
zwischen den einzelnen Höchstausschlägen, die so genannten peak-to-peak-<br />
Amplituden P1N1 und N1P2, wurden von EPEvaluate automatisch berechnet,<br />
ebenso wie die zugehörigen Latenzzeiten. Peak-to-peak-Amplituden haben<br />
den Vorteil, dass Schwankungen der Baseline keinen Einfluss auf die Differenz<br />
ausüben. Gleichzeitig ist bei signifikanten statistischen Ergebnissen<br />
jedoch nicht mehr klar, welcher Einzelkomponente dieses Resultat zuzuschreiben<br />
ist. Deshalb interessierte auch der Unterschied zwischen den<br />
Einzelamplituden und der Baseline, also dem Zeitabschnitt vor dem Ereignis,<br />
die als Nulllinie des ereigniskorrelierten Potentials dient. Hierfür wurden<br />
zusätzlich die base-to-peak-Amplituden P1, N1 und P2 manuell berechnet.<br />
119
120<br />
Die Untersuchung<br />
Die Lokalisation des Maximums eines Potentials erfolgt meist über die<br />
Bestimmung der Elektrode, an der das Potential maximal ist. Wie bereits<br />
beschrieben, haben Voruntersuchungen die Maximalausschläge für olfaktorische<br />
Reize bei der Ableiteposition Pz und für trigeminale Reize bei Cz<br />
identifiziert, so dass sich die Auswertungen vorwiegend auf die entsprechenden<br />
Elektroden beziehen.<br />
Um mögliche Lateralisierungs- und Frontalisierungseffekte in Abhängigkeit<br />
von der Reizklasse und/oder der Gruppenzugehörigkeit untersuchen zu<br />
können, wurden außerdem Potentiale durch Differenzbildung ermittelt.<br />
Hierbei wurden die Potentiale der beiden Hemisphären voneinander subtrahiert<br />
bzw. Unterschiede zwischen den Ableitungspositionen Pz und Cz mit<br />
der Differenz zwischen Cz und Fz verglichen.<br />
Zur Quellenlokalisation des Potentials wäre jedoch eine hohe Dichte von<br />
Elektroden und eine absolute Gleichverteilung von Elektroden erforderlich<br />
gewesen, was bei dem üblichen 10-20-System nicht gewährleistet ist (Universität<br />
Trier - Fachbereich I: Psychologie, 2003). Eine Lokalisation der<br />
cerebralen Aktivitäten erfolgte mit der fMRT-Untersuchung. Durch die<br />
damit identifizierten beteiligten Hirnareale wurde eine Rekonstruktion des<br />
zeitlichen Verlaufs der cerebralen Reizprozessierung erst möglich.<br />
6.7.4. Ergebnisse der Auswertung der EEG-Daten<br />
In den folgenden Kapiteln werden die Ergebnisse der EEG-Untersuchung<br />
vorgestellt. Zu Beginn liegt der Fokus dabei auf der Identifikation von<br />
Amplitudenmaxima, um in der Folge die Darstellung auf die wichtigsten<br />
Ableitepositionen beschränken zu können. Anschließend wird auf die Analyse<br />
der Psychophysikdaten eingegangen, bevor abschließend der Zusammenhang<br />
zwischen den verschiedenen Datenquellen untersucht wird.<br />
Statistische Vorbemerkungen<br />
Bevor verschiedene Tests zur Überprüfung signifikanter Unterschiede zwischen<br />
den beiden Versuchsbedingungen durchgeführt werden konnten,<br />
mussten die Einzelvariablen zunächst auf ihre Verteilungsform überprüft
Die Untersuchung<br />
werden, um adäquate Rechenverfahren anwenden zu können. Anhand des<br />
Kolmogorov-Smirnov-Tests wurden alle Daten auf Normalverteilung getestet.<br />
Mit Ausnahme weniger Variablen wurde diese Voraussetzung erfüllt.<br />
Somit konnten unter Berücksichtigung der kleinen Stichprobe vorwiegend<br />
Varianzanalysen (ANOVA) und t-Tests für abhängige bzw. unabhängige<br />
Variablen einsetzt werden. Als unabhängig konnten die beiden Stichproben<br />
Nichtraucher und Raucher betrachtet werden, da sie zufällig ausgewählt<br />
wurden und die Parallelität der beiden Gruppen erst nachträglich getestet<br />
wurde. Für den Vergleich zwischen Rauchern und Rauchern im Entzug<br />
wurden t-Tests für abhängige Stichproben eingesetzt, da es sich um einen<br />
Prä-Post-Vergleich der gleichen Teilnehmer handelte. In allen Fällen wurde<br />
dann die konservativere Schätzung gewählt, wenn der Levene-Test auf<br />
Varianzengleichheit einen Wert von 0,05 unterschritt. Die verbliebenen<br />
nicht normalverteilten Variablen wurden mit Hilfe des Wilcoxon-Tests für<br />
Rangsummen auf Signifikanz getestet.<br />
Führt man nun mit allen Variablen einen Vergleich Nichtraucher vs. Raucher<br />
und Raucher vs. Raucher im Entzug mit Hilfe von t-Tests durch, so<br />
resultiert eine große Anzahl von Einzelvergleichen, so dass eine a-Fehler-<br />
Korrektur erforderlich gewesen wäre. Da jedoch zunächst mit Hilfe von<br />
Varianzanalysen die relevanten Gruppenunterschiede identifiziert und die t-<br />
Tests lediglich im Sinne von explorativen Tests eingesetzt wurden, um die<br />
bereits erhaltenen Signifikanzen besser differenzieren zu können, wurde auf<br />
den Einsatz der Bonferoni-Korrektur verzichtet. Wegen der fehlenden Korrektur<br />
wurden hierbei keine statistischen Trends, sondern ausschließlich<br />
signifikante Werte beachtet.<br />
Identifikation der Amplitudenmaxima<br />
Wie bereits erwähnt, wurden zunächst die Ableitepositionen identifiziert,<br />
bei denen die Amplituden für die einzelnen Reizklassen maximal waren, um<br />
eine Reduktion der Datenmenge für nachfolgende Rechnungen zu ermöglichen.<br />
Unter Einbeziehung aller Gruppen kristallisierte sich im olfaktorischen<br />
Bereich die Ableiteposition Pz als Maximum mit einer leichten Frontalisierungstendenz<br />
in zentrale Regionen heraus, was sich mit den Ergebnissen<br />
aus verschiedenen Voruntersuchungen deckt (Kobal & Hummel, 1988,<br />
121
122<br />
Die Untersuchung<br />
1991, 1994; Livermore et al., 1992). Die Werte für die einzelnen Reizklassen<br />
können den Tabellen 2, 3 und 4 entnommen werden. Dabei ist das<br />
Amplitudenmaximum jeweils hervorgehoben.<br />
C3 C4 Fz Pz Cz<br />
P1 0,013693 0,017700 0,019500 0,036713 0,024647<br />
N1 -0,028953 -0,030667 -0,023427 -0,026113 -0,027573<br />
P2 0,084447 0,099833 0,073820 0,144653 0,110873<br />
P1N1 0,042647 0,048367 0,042927 0,062827 0,048493<br />
N1P2 0,113400 0,130500 0,097247 0,170767 0,131053<br />
Tabelle 2: Amplitudenmaxima für olfaktorisches S-Nikotin über alle Untersuchungsgruppen<br />
C3 C4 Fz Pz Cz<br />
P1 0,025727 0,021213 0,029033 0,035380 0,025513<br />
N1 -0,021787 -0,020673 -0,022647 -0,021827 -0,023513<br />
P2 0,070120 0,080900 0,068307 0,128027 0,084820<br />
P1N1 0,047513 0,041887 0,051680 0,066060 0,084820<br />
N1P2 0,091907 0,101573 0,090953 0,142727 0,108333<br />
Tabelle 3: Amplitudenmaxima für olfaktorisches R-Nikotin über alle Untersuchungsgruppen<br />
C3 C4 Fz Pz Cz<br />
P1 0,021087 0,023300 0,032067 0,025373 0,032353<br />
N1 -0,028740 -0,032580 -0,023820 -0,040140 -0,028900<br />
P2 0,068380 0,087767 0,080287 0,152287 0,098440<br />
P1N1 0,049827 0,055880 0,050007 0,065513 0,061253<br />
N1P2 0,097120 0,120347 0,098727 0,192427 0,127340<br />
Tabelle 4: Amplitudenmaxima für Rose über alle Untersuchungsgruppen<br />
Bei einer getrennten Betrachtung der einzelnen Untersuchungsgruppen<br />
bestätigte sich die Ableiteposition Pz als Ort der größten Amplituden mit<br />
einer leichten Verschiebung zu den zentralen Ableitepositionen Cz, C3 und<br />
C4 (Tabellen s. Anhang II). Eine genaue Untersuchung der Maxima wäre<br />
mit Hilfe von Brain-Mapping und einer hohen Anzahl von Elektroden möglich.<br />
Dies wurde in der Literatur bisher jedoch nicht gemacht.
Die Untersuchung<br />
Für die Reizklassen in trigeminaler Konzentration fand sich über alle Gruppen<br />
hinweg eine größere Frontalisierungstendenz im Vergleich zu den olfaktorischen<br />
Reizen, so dass sich die Werte von Pz und Cz annäherten.<br />
Diese Werte können den Tabellen 5, 6 und 7 entnommen werden, wobei<br />
auch hier die Amplitudenmaxima jeweils hervorgehoben sind.<br />
C3 C4 Fz Pz Cz<br />
P1 0,016002 0,016262 0,019304 0,019524 0,018316<br />
N1 -0,030342 -0,040778 -0,024587 -0,035684 -0,037684<br />
P2 0,087716 0,094211 0,084242 0,125984 0,107469<br />
P1N1 0,046344 0,055502 0,043891 0,056376 0,056000<br />
N1P2 0,121416 0,132620 0,108829 0,161669 0,145153<br />
Tabelle 5: Amplitudenmaxima für trigeminales S-Nikotin über alle Untersuchungsgruppen<br />
C3 C4 Fz Pz Cz<br />
P1 0,012453 0,012162 0,020804 0,014580 0,016520<br />
N1 -0,033238 -0,039200 -0,018407 -0,030424 -0,030198<br />
P2 0,090182 0,100251 0,101484 0,123173 0,113262<br />
P1N1 0,039007 0,052731 0,039978 0,044918 0,046718<br />
N1P2 0,114742 0,139451 0,106411 0,153518 0,143460<br />
Tabelle 6: Amplitudenmaxima für trigeminales R-Nikotin über alle Untersuchungsgruppen<br />
C3 C4 Fz Pz Cz<br />
P1 0,013962 0,018689 0,018833 0,020191 0,015478<br />
N1 -0,030947 -0,038609 -0,023764 -0,032698 -0,040287<br />
P2 0,087609 0,100564 0,098196 0,126942 0,108689<br />
P1N1 0,044909 0,057298 0,045404 0,052889 0,054013<br />
N1P2 0,118556 0,139173 0,123487 0,159640 0,146318<br />
Tabelle 7: Amplitudenmaxima für CO2 über alle Untersuchungsgruppen<br />
Auch hier konnten die Ergebnisse aus dem Mittelwertsvergleich für alle<br />
Untergruppen bestätigt werden. Dabei lagen die Maximalwerte in den<br />
Gruppen Raucher und Nichtraucher tendenziell eher im parietalen Bereich,<br />
während diese für Raucher im Entzug für nahezu alle Amplituden über den<br />
123
124<br />
Die Untersuchung<br />
zentralen Ableitepositionen zu finden waren (Tabellen s. Anhang II). Durch<br />
die Annäherung der Werte von Cz und Pz können die vorliegenden Ergebnisse<br />
trotz des parietalen Schwerpunkts als weitgehend übereinstimmend<br />
mit den genannten Voruntersuchungen angesehen werden (Kobal & Hummel,<br />
1988, 1991, 1994; Livermore et al., 1992).<br />
Da sich die Amplitudenmaxima für fast alle Variablen bei den Ableitepositionen<br />
Pz und Cz bzw. über zentralen Ableitepositionen befanden, diese nur<br />
in wenigen Einzelfällen frontal lokalisiert waren, und sich diese Ergebnisse<br />
mit denen früherer Untersuchungen decken, beschränken sich die folgenden<br />
Berechnungen in erster Linie auf die beiden erstgenannten Elektroden. Die<br />
Aspekte Lateralisierung und Frontalisierung werden in den folgenden Abschnitten<br />
gesondert behandelt.<br />
Auswertung der Amplituden<br />
Den Hypothesen entsprechend traten in den späten Komponenten n1p2 und<br />
p2 Unterschiede in der Wahrnehmung verschiedener Reizklassen auf. Für<br />
die Ableiteposition Pz ergab eine univariate Varianzanalyse mit den Faktoren<br />
Reizklasse und Rauchstatus für olfaktorische Konzentrationen einen<br />
signifikanten Einfluss der Gruppenzugehörigkeit auf die genannten Amplituden<br />
(n1p2: F = 8,971, df = 2, p = 0,000; p2: F = 11,14, df = 2, p = 0,000).<br />
Dabei zeigten Nichtraucher durchgehend die größten Amplituden. Außer<br />
bei R-Nikotin resultierten bei normalem Konsumverhalten im Vergleich<br />
zum Entzugszustand höhere Werte. Für das künstliche Enantiomer waren<br />
die Amplituden im Entzug tendenziell größer (s. Anhang II). Auch im trigeminalen<br />
Bereich konnte für die gleichen Komponenten ein statistischer<br />
Trend hinsichtlich des Faktors Rauchstatus für diese Elektrodenableitung<br />
beobachtet werden (n1p2: F = 2,66, df = 2, p = 0,074; p2: F = 2,77, df = 2, p<br />
= 0,066), wobei auch hier Nichtraucher die größten Amplituden aufwiesen.<br />
Bei Rauchern waren hier durchgehend höhere Werte zu beobachten als bei<br />
den Probanden im Entzug (s. Anhang II). Für alle anderen Amplituden<br />
traten keine signifikanten Einflüsse der Faktoren auf. Für die Ableiteposition<br />
Cz konnten in der olfaktorischen Konzentration ebenfalls Einflüsse des<br />
Faktors Rauchstatus festgestellt werden. Neben den bereits beobachteten<br />
Unterschieden in den späten Komponenten (n1p2: F = 4,28, df = 2, p =
Die Untersuchung<br />
0,016; p2: F = 5,84, df = 2, p = 0,004) waren hier jedoch auch signifikante<br />
Differenzen in den frühen Amplituden zu erkennen (p1: F = 4,65, df = 2, p<br />
= 0,011; p1n1: F = 3,30, df = 2, p = 0,04). Die größten Amplituden waren<br />
für wiederum weitgehend für Nichtraucher zu beobachten. Nach Applikation<br />
der beiden Nikotinenantiomere waren für die Amplitude p1n1 jedoch die<br />
Werte in der Entzugsgruppe größer. Außerdem drehte sich hier das Verhältnis<br />
zwischen den beiden Rauchbedingungen um. Im Entzug fielen alle<br />
Amplituden größer aus (s. Anhang II). Dagegen traten für die trigeminalen<br />
Reize über Cz keine statistisch beachtenswerten Einflüsse der untersuchten<br />
Faktoren auf.<br />
Aufbauend auf den Ergebnissen der genannten Varianzanalysen wurden<br />
weitere ANOVAs über alle Ableitepositionen mit den Faktoren Geruchsklasse<br />
und Rauchstatus gerechnet. Jedoch wurde in den nachfolgenden<br />
Berechnungen der Fokus auf statistische Signifikanzen in den Vergleichen<br />
Raucher vs. Nichtraucher und Raucher vs. Raucher im Entzug gelegt. Entsprechend<br />
wurden in die Analysen jeweils nur zwei Untersuchungsgruppen<br />
eingeschlossen. Zwischen erstgenannten beiden Gruppen ergaben sich dabei<br />
sowohl im olfaktorischen als auch im trigeminalen Bereich signifikante<br />
Unterschiede bzw. statistische Trends mit Ausnahme der trigeminalen<br />
Amplitude p1 für alle Einzelamplituden, wobei Nichtraucher mit größeren<br />
Ausschlägen reagierten (s. Anhang II). Die Ergebnisse sind der Tabelle 8 zu<br />
entnehmen.<br />
125
126<br />
Die Untersuchung<br />
Amplitude F-Wert Anzahl der Freiheitsgrade Signifikanz<br />
P1, olfaktorisch 21,48 1 0,000*<br />
N1, olfaktorisch 8,31 1 0,004*<br />
P2, olfaktorisch 38,23 1 0,000*<br />
P1N1, olfaktorisch 27,21 1 0,000*<br />
N1P2, olfaktorisch 35,97 1 0,000*<br />
P1, trigeminal 0,014 1 0,905<br />
N1, trigeminal 9,65 1 0,002*<br />
P2, trigeminal 3,47 1 0,063<br />
P1N1, trigeminal 8,67 1 0,003*<br />
N1P2, trigeminal 9,99 1 0,002*<br />
Tabelle 8: Vergleich der Amplituden Raucher vs. Nichtraucher<br />
Im zweiten Vergleich Raucher vs. Raucher im Entzug traten statistische<br />
Signifikanzen jedoch nur im olfaktorischen Bereich in späten Komponenten<br />
auf. Diese sind in Tabelle 9 aufgelistet. Für die trigeminalen Konzentrationen<br />
trat lediglich ein statistischer Trend für die Amplitude p1n1 auf (F =<br />
3,41, df = 1, p = 0,065). Die Amplituden in der Entzugsgruppe fielen erneut<br />
größer aus als bei den Rauchern (s. Anhang II).
Die Untersuchung<br />
Amplitude F-Wert Anzahl der Freiheitsgrade Signifikanz<br />
P1, olfaktorisch 0,245 1 0,621<br />
N1, olfaktorisch 13,71 1 0,000*<br />
P2, olfaktorisch 7,63 1 0,003*<br />
P1N1, olfaktorisch 10,99 1 0,001*<br />
N1P2, olfaktorisch 14,02 1 0,000*<br />
Tabelle 9: Vergleich der Amplituden Raucher vs. Raucher im Entzug<br />
Schließlich interessierte bei der Analyse der Amplituden der Einfluss der<br />
einzelnen Reizklassen auf die unterschiedlichen EEG-Antworten der Untersuchungsgruppen.<br />
Dabei unterschieden sich die Teilnehmer in den trigeminalen<br />
Konzentrationen weder für die beiden Nikotinsorten, noch für CO2.<br />
Für die ebenfalls getrennt betrachteten olfaktorischen Reizklassen konnten<br />
die bereits beobachteten Unterschiede jedoch tendenziell erneut bestätigt<br />
werden (Tabelle s. Anhang II).<br />
Mit Hilfe explorativer t-Tests wurden die Signifikanzen noch einmal hinsichtlich<br />
der Reizklassen und Ableitepositionen getrennt untersucht. Dabei<br />
ergaben sich im Vergleich Raucher vs. Nichtraucher für keine trigeminale<br />
Reizklasse relevante Unterschiede zwischen den beiden Gruppen. Für olfaktorisches<br />
S-Nikotin fanden sich zentral und parietal statistisch signifikante<br />
Differenzen oder nur knapp über der Signifikanzgrenze liegende Werte in<br />
den späten Komponenten (C3, Amplitude n1: T = 1,97, df = 28, 0,059; C4,<br />
Amplitude p2: T = 2,16, df = 19, p = 0,043; Pz, Amplitude p2: T = -2,02, df<br />
= 23, 0,056). Für olfaktorisches R-Nikotin ergab sich ebenfalls eine Signifikanz<br />
über der Ableiteposition Pz in der Amplitude p2 (T = 2,13, df = 24, p<br />
= 0,044). Die größten Unterschiede fanden sich jedoch für Rose, wo der<br />
Vergleich vor allem für frühe Komponenten signifikant ausfiel (C3, Ampli-<br />
127
128<br />
Die Untersuchung<br />
tude p1: T = -2,59, df = 17, p = 0,019; C3, Amplitude p1n1: T = -2,35, df =<br />
25, p = 0,026; C4, Amplitude n1: T = 2,24, df = 23, p = 0,035; C4, Amplitude<br />
p1n1: T = 2,05, df = 24, p = 0,05; Cz, Amplitude p1: T = -2,09, df =<br />
21, p = 0,049; Fz, Amplitude p1: T = -2,39, df = 19, p = 0,027). Im parietalen<br />
Bereich wurden hingegen ausschließlich späte Komponenten signifikant<br />
(Amplitude p2: T = 2,40, df = 18, p = 0,027; Amplitude n1p2: T = 2,14, df<br />
= 16, p = 0,048). Für die t-Test-Vergleiche der beiden Gruppen Raucher vs.<br />
Raucher im Entzug fand sich nur eine statistische Signifikanz im zentralen<br />
Bereich für olfaktorisches S-Nikotin (C3, Amplitude p1: T = -2,55, df = 14,<br />
p = 0,023).<br />
Insgesamt betrachtet, fielen die Amplituden der Nichtraucher in den olfaktorischen<br />
Konzentrationen konstant größer aus als in den anderen beiden<br />
Untersuchungsgruppen. Dieser eindeutige Trend konnte für trigeminale<br />
Reizklassen nicht beobachtet werden. Exemplarisch sind in der Abbildung<br />
14 die Größen der Amplituden für beide Reizklassen dargestellt.
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Amplitude p2, Kanal Pz, S-Nikotin olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Amplitude p2, Kanal Pz, R-Nikotin olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Amplitude p2, Kanal Pz, Rose olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Die Untersuchung<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Amplitude p2, Kanal Cz, S-Nikotin trigeminal<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
0,25 Amplitude p2, Kanal Cz, R-Nikotin trigeminal<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
0,25 Amplitude p2, Kanal Cz, CO2 trigeminal<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Abbildung 14: Vergleich der Untersuchungsgruppen hinsichtlich der Amplitude p2<br />
C<br />
129
130<br />
Auswertung der Latenzzeiten<br />
Die Untersuchung<br />
Auch für die Latenzzeiten wurden zunächst analog zu der Berechnung der<br />
Amplituden ANOVAs mit den beiden Faktoren Reizklasse und Rauchstatus<br />
für die beiden Ableitepositionen Pz und Cz gerechnet, bei denen die maximale<br />
Antwort des Gehirns beobachtet werden konnte. Dabei ergab sich für<br />
beide Orte in der olfaktorischen Konzentration ein signifikanter Einfluss des<br />
Rauchstatus auf die Latenzzeit p2 (Pz: F = 5,09, df = 2, p = 0,007; Cz: F =<br />
4,380, df = 2, p = 0,014), wobei Raucher im Entzug am schnellsten eine<br />
Reaktion zeigten. Die Latenzzeiten der Nichtraucher fielen im Vergleich zu<br />
denen der Raucher ebenfalls kürzer aus. Im trigeminalen Bereich konnten<br />
erneut keine Unterschiede gefunden werden.<br />
Wieder wurden weitere ANOVAs über alle Ableitepositionen mit den identischen<br />
Faktoren für die Vergleiche Raucher vs. Nichtraucher und Raucher<br />
vs. Raucher im Entzug gerechnet. Im ersten Vergleich resultierte in der<br />
olfaktorischen Konzentration lediglich ein statistischer Trend für den Faktor<br />
Geruch hinsichtlich der Latenzzeit n1 (F = 2,835, df = 2, p = 0,06), wobei<br />
trigeminale Reize zu einer schnelleren Antwort des Gehirns führten. Im<br />
trigeminalen Bereich ergaben sich für die beiden Faktoren eine signifikante<br />
Wechselwirkung für die beiden früheren Latenzzeiten (p1: F = 3,41, df = 2,<br />
p = 0,034; n1: F = 4,63, df = 2, p = 0,01). Nichtraucher reagierten zunehmend<br />
schneller, je trigeminaler der Reiz wurde (von R-Nikotin über S-<br />
Nikotin zu CO2). Für die Latenzzeit p2 ergab sich hingegen ein signifikanter<br />
Einfluss der beiden Einzelfaktoren (Geruch: F = 5,25, df = 2, p = 0,006;<br />
Rauchstatus: F = 4,04, df = 1, p = 0,045) in der bereits beschriebenen Richtung.<br />
Raucher und Raucher im Entzug unterschieden sich unter Berücksichtung<br />
des Faktors Geruch hinsichtlich aller olfaktorischen Latenzzeiten (p1:<br />
F = 13,71, df = 1, p = 0,000; n1: F = 11,5, df = 1, p = 0,001; p2: F = 39,94,<br />
df = 1, p = 0,000), wobei auf CO2 gefolgt von S-Nikotin am schnellsten<br />
reagiert wurde. Im trigeminalen Bereich fanden sich ein entsprechender<br />
statistischer Trend für die Latenzzeit n1 durch den Faktor Geruch (F = 2,91,<br />
df = 2, p = 0,055) und ein signifikanter Einfluss des Rauchstatus auf die<br />
Latenzzeit p2 (F = 5,6, df = 1, p = 0,018), sowie ein statistischer Trend der<br />
Wechselwirkung (F = 2,85, df = 2, p = 0,059). Raucher im Entzug reagier-
Die Untersuchung<br />
ten wie die Nichtraucher mit zunehmenden trigeminalen Aspekten schneller<br />
als die Raucher.<br />
Die nachfolgenden explorativen t-Tests dienten wiederum dazu, die Signifikanzen<br />
noch einmal hinsichtlich der Reizklassen und Ableitepositionen<br />
getrennt zu untersuchen. Im Vergleich Raucher vs. Nichtraucher resultierten<br />
dabei keine Unterschiede. Wie aus den ANOVAs bereits zu erwarten war,<br />
fielen die Differenzen zwischen Rauchern und Rauchern im Entzug größer<br />
aus. Jedoch konzentrierten sie sich zum einen ausschließlich auf den olfaktorischen<br />
Bereich und zum anderen mit einer einzigen Ausnahme auf die<br />
Latenzzeit p2. Die Ergebnisse sind in Tabelle 10 dargestellt.<br />
Latenzzeit T-Wert<br />
Anzahl der<br />
Freiheitsgrade<br />
Signifikanz<br />
P2, Kanal C3, Rose, olfaktorisch 3,180 14 0,007*<br />
P1, Kanal C4, Rose, olfaktorisch 2,402 14 0,031*<br />
P2, Kanal C4, Rose, olfaktorisch -2,521 14 0,024*<br />
P2, Kanal Cz, Rose, olfaktorisch -2,693 14 0,017*<br />
P2, Kanal Fz, Rose, olfaktorisch -2,516 14 0,025*<br />
P2, Kanal Pz, Rose, olfaktorisch -2,90 14 0,012*<br />
P2, Kanal C4, S-Nikotin, olfaktorisch -2,292 14 0,038*<br />
P2, Kanal C4, R-Nikotin, olfaktorisch -2,927 14 0,011*<br />
P2, Kanal Fz, R-Nikotin, olfaktorisch -2,682 14 0,018*<br />
P2, Kanal Cz, R-Nikotin, olfaktorisch -2,915 14 0,011*<br />
P2, Kanal Pz, R-Nikotin, olfaktorisch -2,914 14 0,011*<br />
Tabelle 10: Vergleich der Latenzzeiten Raucher vs. Raucher im Entzug<br />
Wie der Abbildung 15 zu entnehmen ist, fiel die Latenzzeit p2 der Raucher<br />
im Entzug in den olfaktorischen Konzentrationen im Vergleich zu den beiden<br />
anderen Gruppen kürzer aus.<br />
131
132<br />
800<br />
600<br />
400<br />
200<br />
0<br />
800<br />
600<br />
400<br />
200<br />
0<br />
800<br />
600<br />
400<br />
200<br />
0<br />
Latenzzeit p2, Kanal Pz, S-Nikotin olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Latenzzeit p2, Kanal Pz, R-Nikotin olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Latenzzeit p2, Kanal Pz, Rose olfaktorisch<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Die Untersuchung<br />
800<br />
600<br />
400<br />
200<br />
0<br />
800<br />
600<br />
400<br />
200<br />
0<br />
800<br />
600<br />
400<br />
200<br />
0<br />
Latenzzeit p2, Kanal Cz, S-Nikotin trigeminal<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Latenzzeit p2, Kanal Cz, R-Nikotin trigeminal<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Latenzzeit p2, Kanal Cz, CO2 trigeminal<br />
Nichtraucher Raucher<br />
im Entzug<br />
Raucher<br />
Abbildung 15: Vergleich der Untersuchungsgruppen hinsichtlich der Latenzzeit p2
Die Untersuchung<br />
Auswertung von Frontalisierungs – und Lateralisierungstendenzen<br />
Um zu überprüfen, ob generell statistische Unterschiede zwischen den einzelnen<br />
Ableitepositionen aufgetreten waren, wurden zu Beginn univariate<br />
ANOVAs für die einzelnen Untersuchungsgruppen getrennt gerechnet. Für<br />
die Prüfung einer Lateralisierung der Reizverarbeitung wurden dabei zunächst<br />
lediglich die beiden Elektroden C3 und C4 in die Auswertung eingeschlossen.<br />
Dabei ergab sich für Raucher lediglich ein signifikanter Unterschied<br />
für die olfaktorische Amplitude p1 mit einer Dominanz der linken<br />
Hemisphäre (F = 4,40, df = 1, p = 0,039) und ein statistischer Trend für die<br />
trigeminale Amplitude p1n1 mit linksseitig stärker ausgeprägten Komponenten<br />
(F = 3,08, df = 1, p = 0,083). Bei Rauchern im Entzug resultierte ein<br />
statistischer Trend für die olfaktorische Amplitude n1 (F = 2,90, df = 1, p =<br />
0,092). Aus Abbildung 16 wird ersichtlich, dass es sich dabei um eine<br />
rechtshemisphärische Dominanz handelt, die ausschließlich unter S-Nikotin<br />
auftritt. Für alle anderen Komponenten war diese Lateralisierungstendenz<br />
nicht zu beobachten (s. Graphiken Anhang III). Bei Nichtrauchern wurden<br />
keine Unterschiede zwischen den beiden Ableitepositionen deutlich. Die<br />
nähere Untersuchung der Einflüsse einzelner Reizklassen mit Hilfe explorativer<br />
t-Tests führte bei Nichtrauchern lediglich unter CO2 für die Amplitude<br />
p1 zu signifikanten Unterschieden mit einer linksseitigen Dominanz (T =<br />
2,78, df = 14, p = 0,015). Bei Rauchern reagierten die beiden Gehirnhälften<br />
unter olfaktorischem Nikotin in den Amplituden p1 (T = -2,91, df = 14, p =<br />
0,046) und p1n1 (T = 2,71, df = 14, p = 0,017), unter Rose für die Amplitude<br />
p1 (T = -2,24, df = 14, p = 0,042) und für trigeminales R-Nikotin in der<br />
Amplitude p1n1 (T = 2,84, df = 14, p = 0,013) unterschiedlich. Die Dominanz<br />
war dabei in allen Fällen linkshemisphärisch lokalisiert. Bei Rauchern<br />
im Entzug hingegen war keine Lateralisierung zu beobachten.<br />
133
134<br />
0,030<br />
0,025<br />
0,020<br />
0,015<br />
0,010<br />
0,005<br />
0,000<br />
0,06<br />
0,05<br />
0,04<br />
0,03<br />
0,02<br />
0,01<br />
0,00<br />
Raucher, Amplitude p1, olfaktorisch<br />
C3 C4 C3 C4 C3 C4<br />
S-Nikotin R-Nikotin Rose<br />
Raucher, Amplitude p1n1, olfaktorisch<br />
C3 C4 C3 C4 C3 C4<br />
S-Nikotin R-Nikotin<br />
Rose<br />
-0,5<br />
-0,4<br />
-0,3<br />
-0,2<br />
-0,1<br />
0,0<br />
Die Untersuchung<br />
0,030<br />
0,025<br />
0,020<br />
0,015<br />
0,010<br />
0,005<br />
0,000<br />
0,020<br />
0,015<br />
0,010<br />
0,005<br />
0,000<br />
Raucher, Amplitude p1n1, trigeminal<br />
C3 C4 C3 C4 C3 C4<br />
S-Nikotin R-Nikotin<br />
CO2<br />
0,025 Nichtraucher, Amplitude p1, trigeminal<br />
Raucher im Entzug, Amplitude n1, olfaktorisch<br />
C3 C4 C3 C4 C3 C4<br />
S-Nikotin R-Nikotin<br />
Rose<br />
C3 C4 C3 C4 C3 C4<br />
S-Nikotin R-Nikotin<br />
CO2<br />
Abbildung 16: Signifikante Lateralisierungstendenzen getrennt nach Untersuchungsgruppen<br />
Bei der Untersuchung einer Frontalisierungstendenz wurden hingegen die<br />
drei Ableitepositionen Fz, Cz und Pz in die Analyse einbezogen. Dabei<br />
ergaben sich in den ANOVAs signifikante Werte in der Gruppe Raucher<br />
mit parietalem Schwerpunkt für die olfaktorische Amplitude n1p2 (F =
Die Untersuchung<br />
4,06, df = 2, p = 0,019), die olfaktorische Amplitude p2 (F = 7,35, df = 2, p<br />
= 0,001), die trigeminale Amplitude n1p2 (F = 7,39, df = 2, p = 0,001) und<br />
die trigeminale Amplitude p2 (F = 3,34, df = 2, p = 0,038). Bei Nichtrauchern<br />
resultierten signifikante Unterschiede ebenfalls zugunsten der parietalen<br />
Ableiteposition zwischen den untersuchten Elektroden für die olfaktorische<br />
Amplitude n1p2 (F = 5,80, df = 2, p = 0,004), die olfaktorische Amplitude<br />
p2 (F = 7,56, df = 2, p = 0,001), die trigeminale Amplitude n1p2 (F =<br />
4,07, df = 2, p = 0,019) und die trigeminale Amplitude p2 (F = 3,75, df = 2,<br />
p = 0,026). Wie bereits aus den Amplitudenmaxima ersichtlich wurde, können<br />
die Unterschiede generell im Sinne eines parietalen Schwerpunkts interpretiert<br />
werden, was gegen eine Frontalisierungstendenz spricht. Für<br />
Raucher im Entzug konnten erneut keine Unterschiede zwischen den Positionen<br />
beobachtet werden. Die signifikanten Tendenzen werden in den Abbildungen<br />
17 und 18 im Vergleich der einzelnen Ableitungspositionen dargestellt.<br />
0,14<br />
0,12<br />
0,10<br />
0,08<br />
0,06<br />
0,04<br />
0,02<br />
0,00<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Raucher, Amplitude n1p2, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Raucher, Amplitude n1p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
0,12<br />
0,10<br />
0,08<br />
0,06<br />
0,04<br />
0,02<br />
0,00<br />
0,18<br />
0,16<br />
0,14<br />
0,12<br />
0,10<br />
0,08<br />
0,06<br />
0,04<br />
0,02<br />
0,00<br />
Raucher, Amplitude p2, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Raucher, Amplitude p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Abbildung 17: Signifikante Frontalisierungstendenzen bei Rauchern<br />
135
136<br />
0,30<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
0,25<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Nichtraucher, Amplitude n1p2, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Nichtraucher, Amplitude n1p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Die Untersuchung<br />
0,4<br />
0,3<br />
0,2<br />
0,1<br />
0,0<br />
0,20<br />
0,18<br />
0,16<br />
0,14<br />
0,12<br />
0,10<br />
0,08<br />
0,06<br />
0,04<br />
0,02<br />
0,00<br />
Nichtraucher, Amplitude p2, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Nichtraucher, Amplitude p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Abbildung 18: Signifikante Frontalisierungstendenzen bei Nichtrauchern<br />
Zur näheren Untersuchung des Einflusses einzelner Reizklassen wurden<br />
auch hier explorative t-Tests eingesetzt. Dabei fand sich für Nichtraucher<br />
eine statistisch signifikante Tendenz in Richtung der Ableiteposition Fz für<br />
die Amplitude p1 bei der Gabe von CO2 (T = -2,516, df = 14, p = 0,049),<br />
für Raucher konnte keine derartige Tendenz festgestellt werden. Dagegen<br />
ergaben sich bei Rauchern im Entzug für jede Reizklasse vor allem in den<br />
späteren Komponenten Frontalisierungstendenzen mit einem zentralen<br />
Schwerpunkt, was sich mit den Ergebnissen aus der Bestimmung der Amplitudenmaxima<br />
deckt. Die signifikanten Frontalisierungstendenzen für Raucher<br />
im Entzug werden in der Abbildung 19 dargestellt.
0,07<br />
0,06<br />
0,05<br />
0,04<br />
0,03<br />
0,02<br />
0,01<br />
0,00<br />
0,12<br />
0,10<br />
0,08<br />
0,06<br />
0,04<br />
0,02<br />
0,00<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Raucher im Entzug, Amplitude p1n1, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Raucher im Entzug, Amplitude p2, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Raucher im Entzug, Amplitude n1p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Die Untersuchung<br />
0,030<br />
0,025<br />
0,020<br />
0,015<br />
0,010<br />
0,005<br />
0,000<br />
-0,12<br />
-0,10<br />
-0,08<br />
-0,06<br />
-0,04<br />
-0,02<br />
0,00<br />
0,20<br />
0,15<br />
0,10<br />
0,05<br />
0,00<br />
Raucher im Entzug, Amplitude p1, olfaktorisch<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin Rose<br />
Raucher im Entzug, Amplitude n1, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Raucher im Entzug, Amplitude p2, trigeminal<br />
Pz Cz Fz Pz Cz Fz Pz Cz Fz<br />
S-Nikotin R-Nikotin CO2<br />
Abbildung 19: Signifikante Frontalisierungstendenzen bei Rauchern im Entzug<br />
137
138<br />
Die Untersuchung<br />
Die Ergebnisse der t-Tests für Raucher im Entzug sind in Tabelle 11 zu<br />
sehen.<br />
Reizklasse Amplitude T-Wert df Signifikanz<br />
S-Nikotin olfaktorisch P1N1 2,175 14 0,047*<br />
R-Nikotin olfaktorisch P1 -2,709 14 0,017*<br />
R-Nikotin olfaktorisch P1N1 2,510 14 0,025*<br />
Rose P2 2,322 14 0,036*<br />
S-Nikotin trigeminal N1 2,187 14 0,046*<br />
S-Nikotin trigeminal N1P2 2,374 14 0,032*<br />
R-Nikotin trigeminal P2 -2,933 14 0,011*<br />
R-Nikotin trigeminal N1P2 -2,542 14 0,023*<br />
CO2 P2 2,430 14 0,029*<br />
CO2 N1P2 3,867 14 0,002*<br />
Tabelle 11: Frontalisierungstendenzen bei Rauchern im Entzug<br />
6.7.5. Ergebnisse der Auswertung der psychophysischen Daten<br />
Schwellen von S- und R-Nikotin<br />
Aus der Schwellenbestimmung lagen über die Luftflüsse betrachtet für alle<br />
Untersuchungsgruppen Werte für die beiden Nikotinsorten vor. Im direkten<br />
Vergleich ergaben sich in den olfaktorischen Werten keine Unterschiede in<br />
Abhängigkeit des Rauchstatuses. Auch zwischen den Nikotinsorten gab es<br />
nur geringe Differenzen. In den trigeminalen Schwellen unterschieden sich<br />
Raucher und Raucher im Entzug hinsichtlich der Stechschwelle für S-<br />
Nikotin signifikant (T = 2,52, df = 14, p = 0,025), wobei diese bei Rauchern<br />
im Entzug niedriger lag. Nichtraucher zeigten sich hingegen signifikant<br />
sensibler für die brennenden Eigenschaften von R-Nikotin (T = 2,977, df =<br />
28, p = 0,006). Dieser Unterschied trat tendenziell auch für S-Nikotin auf (T<br />
= 1,92, df = 28, p = 0,066). Die einzelnen Werte können der Tabelle 12<br />
entnommen werden, wobei die Einheit Liter pro Minute (l/min) ist.
Die Untersuchung<br />
Schwelle Raucher Raucher im Entzug Nichtraucher<br />
S-Nikotin olfaktorisch 1,28<br />
(0,12769)<br />
S-Nikotin Brennen 3,23<br />
(0,19309)<br />
S-Nikotin Stechen 6,16<br />
(0,45615)<br />
R-Nikotin olfaktorisch 1,65<br />
(0,13866)<br />
R-Nikotin Brennen 7,33<br />
(0,45593)<br />
R-Nikotin Stechen 7,6<br />
(0,27325)<br />
1,2<br />
(0,14209)<br />
3,19<br />
(0,23215)<br />
5,64<br />
(0,48450)<br />
1,63<br />
(0,13866)<br />
7,35<br />
(0,45793)<br />
7,52<br />
(0,33226)<br />
1,27<br />
(0,12857)<br />
2,73<br />
(0,25299)<br />
6,97<br />
(0,42754)<br />
1,84<br />
(0,13616)<br />
5,33<br />
(0,58276)<br />
7,71<br />
(0,18363)<br />
Tabelle 12: Vergleich der Mittelwerte der Schwellenbestimmung über die Untersuchungsgruppen<br />
(SEMs in Klammern)<br />
Auswertung der psychophysischen Ratings<br />
Mit Hilfe weiterer ANOVAs wurde der Einfluss der Reizklasse auf die<br />
unterschiedlichen psychophysischen Ratings zunächst für jede Untersuchungsgruppe<br />
getrennt bestimmt. Dabei wurden in die Analyse der Ratings<br />
Intensität Brennen und Intensität Stechen ausschließlich trigeminale Reize<br />
eingeschlossen, während für alle anderen Einschätzungen Vergleiche über<br />
alle Reizklassen erfolgten. Für Raucher ergaben sich dabei signifikante<br />
Unterschiede in Abhängigkeit des Geruchs für die Variablen Hedonik (F =<br />
10,84, df = 5, p = 0,000), Intensität Brennen (F = 3,19, df = 2, p = 0,051)<br />
und Intensität Stechen (F = 5,31, df = 2, p = 0,009). Auch bei Rauchern im<br />
Entzug fanden sich in den gleichen Variablen statistische Signifikanzen<br />
oder Trends (Hedonik: F = 9,49, df = 5, p = 0,000; Intensität Brennen: F =<br />
2,69, df = 2, p = 0,08; Intensität Stechen: F = 6,14, df = 2, p = 0,005).<br />
Nichtraucher unterschieden sich unter Berücksichtigung der gültigen Werte<br />
139
140<br />
Die Untersuchung<br />
hinsichtlich ihrer Ratings in Abhängigkeit von den Reizklassen ebenfalls<br />
bezüglich der hedonischen Einschätzung (F = 9,19, df = 5, p = 0,000), der<br />
Intensität Brennen (F = 3,591, df = 2, p = 0,049) und der Intensität Stechen<br />
(F = 5,608, df = 2, p = 0,009). In der Rangreihe der hedonischen Bewertung<br />
der Reizklassen waren sich dabei alle Untersuchungsgruppen im Wesentlichen<br />
einig. Am angenehmsten wurde Rose eingeschätzt. Es folgten olfaktorisches<br />
R-Nikotin, olfaktorisches S-Nikotin, trigeminales R-Nikotin und<br />
trigeminales S-Nikotin. CO2 wurde von allen als am unangenehmsten erlebt.<br />
Nichtraucher empfanden in der trigeminalen Konzentration das S-<br />
Nikotin als geringfügig angenehmer als das andere Enantiomer. Am stärksten<br />
empfanden die Entzugsgruppe und die Rauchergruppe das Brennen und<br />
Stechen für CO2, gefolgt von S-Nikotin. R-Nikotin wies erwartungsgemäß<br />
die geringsten trigeminalen Eigenschaften auf.<br />
Zur Identifikation von Unterschieden zwischen den einzelnen Untersuchungsgruppen<br />
wurden auch hier ANOVAs eingesetzt. In den olfaktorischen<br />
Konzentrationen ergaben sich im Vergleich Raucher vs. Nichtraucher<br />
signifikante Einflüsse des Rauchstatus auf die Einschätzung der Intensität<br />
des Geruchs (F = 3,34, df = 2, p = 0,039) und der Hedonik (F = 7,364, df =<br />
2, p = 0,001). Dabei schätzten Raucher die Reize intensiver und angenehmer<br />
ein als Nichtraucher. Im trigeminalen Bereich resultierte ein signifikanter<br />
Einfluss des Faktors Rauchstatus auf die hedonische Einschätzung (F =<br />
9,61, df = 2, p = 0,000). Auch hier empfand die Rauchergruppe die Reize<br />
als weniger unangenehm. Im Vergleich Raucher vs. Raucher im Entzug<br />
resultierten keine signifikanten Unterschiede.<br />
Zur weiteren Differenzierung der gefundenen Ergebnisse wurden wiederum<br />
explorative t-Tests eingesetzt. Im Vergleich Raucher vs. Nichtraucher zeigten<br />
sich dabei signifikante Unterschiede der hedonischen Einschätzung von<br />
olfaktorischem R-Nikotin (T = 2,55, df = 27, p = 0,017), von Rose (T =<br />
2,49, df = 23,5, p = 0,20), von trigeminalem S- Nikotin (T = 2,34, df = 27, p<br />
= 0,27) und von trigeminalem R-Nikotin (T = 2,60, df = 23,3, p = 0,016).<br />
Zwischen Rauchern und Rauchern im Entzug waren erneut keine Unterschiede<br />
zu beobachten. Nichtraucher schätzten dabei alle Reizklassen als<br />
weniger angenehm ein als die beiden Vergleichsgruppen.
Die Untersuchung<br />
6.7.6. Zusammenhänge zwischen EEG-Daten und den psychophysischen<br />
Ratings<br />
Abschließend soll in diesem Kapitel nach der getrennten Darstellung der<br />
EEG-Daten und der psychophysischen Ratings ein Blick auf mögliche Zusammenhänge<br />
zwischen den einzelnen Variablen geworfen werden. Dazu<br />
werden sowohl Korrelationen zwischen Ratings untereinander, als auch<br />
Einzelkomponenten der EEG-Ableitungen mit subjektiven Einschätzungen<br />
in Relation zueinander untersucht.<br />
Zusammenhänge zwischen Craving, Hedonik und späten EEG-<br />
Komponenten<br />
Da sich in den psychophysischen Daten vor allem Unterschiede in den hedonischen<br />
Bewertungen der Reizklassen ergeben hatten, war auch der Einfluss<br />
dieser Differenzen auf das empfundene Craving bei Rauchern und bei<br />
Rauchern im Entzug interessant. Dieser wurde mit Hilfe von Regressionsanalysen<br />
untersucht. Sowohl für Raucher (F = 19,78, df = 1, p = 0,011) als<br />
auch für entzügige Raucher (F = 62,46, df = 1, p = 0,001) konnten signifikante<br />
Zusammenhänge zwischen den beiden untersuchten Faktoren Hedonik<br />
und Craving gefunden werden. Je angenehmer der Reiz empfunden<br />
wurde, desto stärker ausgeprägt war das Verlangen zu Rauchen (s. Abbildungen<br />
20 und 21).<br />
Die Mittelwerte und Standardfehler der Mittelwerte der beiden Variablen<br />
Craving und Hedonik sind in der Tabelle 13 für die beiden Untersuchungsgruppen<br />
dargestellt.<br />
141
142<br />
Craving<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
CO2 trigeminal<br />
S-Nikotin trigeminal<br />
R-Nikotin trigeminal<br />
S-Nikotin olfaktorisch<br />
Die Untersuchung<br />
R-Nikotin olfaktorisch<br />
Rose olfaktorisch<br />
Hedonik<br />
Abbildung 20: Zusammenhang zwischen Craving und hedonischer Einschätzung bei Rauchern<br />
Craving<br />
45<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
CO2 trigeminal<br />
S-Nikotin trigeminal<br />
R-Nikotin trigeminal<br />
S-Nikotin olfaktorisch<br />
R-Nikotin olfaktorisch<br />
Rose olfaktorisch<br />
Hedonik<br />
Abbildung 21: Zusammenhang zwischen Craving und hedonischer Einschätzung bei Rauchern<br />
im Entzug
Die Untersuchung<br />
Geruchsklasse Variable Raucher Raucher im Entzug<br />
Rose Hedonik 61,36<br />
R-Nikotin olfak-<br />
torisch<br />
S-Nikotin olfak-<br />
torisch<br />
R-Nikotin trige-<br />
minal<br />
S-Nikotin trige-<br />
minal<br />
(4,0445)<br />
Craving 26,68<br />
(6,7383)<br />
Hedonik 46,34<br />
(2,4206)<br />
Craving 26,10<br />
(6,0455)<br />
Hedonik 35,52<br />
(3,4430)<br />
Craving 23,33<br />
(5,5246)<br />
Hedonik 32,45<br />
(5,0931)<br />
Craving 19,52<br />
(3,5434)<br />
Hedonik 29,23<br />
Craving<br />
CO2 Hedonik<br />
Craving<br />
(4,1031)<br />
19,79<br />
(3,7198)<br />
23,93<br />
(4,7051)<br />
16,62<br />
(3,4341)<br />
61,35<br />
(4,0455)<br />
35,57<br />
(5,7371)<br />
46,34<br />
(2,4206)<br />
31,77<br />
(5,7072)<br />
35,52<br />
(3,4430)<br />
29,78<br />
(5,6435)<br />
32,45<br />
(5,0931)<br />
26,44<br />
(5,1624)<br />
29,23<br />
(4,1031)<br />
26,27<br />
(4,5775)<br />
23,93<br />
(4,7051)<br />
22,95<br />
(4,6818)<br />
Tabelle 13: Mittelwerte der Variablen Craving und Hedonik für Raucher und Raucher im<br />
Entzug (SEMs in Klammern)<br />
143
144<br />
Die Untersuchung<br />
Um ausschließen zu können, dass die signifikanten Ergebnisse der Regressionsanalyse<br />
darauf zurückzuführen sein könnten, dass die Daten für die<br />
jeweils gleichen Probanden erhoben wurden und somit voneinander abhängig<br />
waren, wurde eine weitere Regressionsanalyse mit zentrierten und quadrierten<br />
Werten gerechnet. Für Raucher ergab sich dabei zwar ein signifikanter<br />
Einfluss der korrigierten Werte (T = -3,492, df = 2, p = 0,040), was auf<br />
einen Einfluss der Abhängigkeit der Daten auf den Regressionszusammenhang<br />
schließen lässt. Für Raucher im Entzug, wo der Effekt auch signifikant<br />
stärker zu erwarten war, wurde dieser Effekt jedoch nicht beobachtet (T = -<br />
0,717, df = 2, p = 0,525), so dass auf einen tatsächlich vorhandenen Einfluss<br />
der Hedonik des Reizes auf das empfundene Craving geschlossen werden<br />
kann.<br />
Da späte Komponenten von EEG-Ableitungen mit hedonischen Bewertungen<br />
in Verbindung gebracht werden (Evans, Cui & Starr, 1995; Knott,<br />
1991), wurde auch der Zusammenhang zwischen diesen und der hedonischen<br />
Bewertung über alle Gruppen hinweg untersucht. Dabei ergab sich<br />
für die späte Komponente n1p2 ein statistischer Trend (F = 3,04, df = 1, p =<br />
0,084) und eine statistische Signifikanz für die Amplitude p2 (F = 4,43, df =<br />
1, p = 0,037). Craving stand hingegen mit den beiden Latenzzeiten p1 (F =<br />
18,28, df = 1, p = 0,000) und n1 (F = 5,67, df = 1, p = 0,017) in signifikanter<br />
Beziehung.<br />
Zusammenhänge zwischen Intensitäten und frühen EEG-Komponenten<br />
Schließlich interessierte noch der Zusammenhang zwischen den subjektiv<br />
empfundenen Intensitäten und den frühen Komponenten, die in anderen<br />
Untersuchungen bereits mit physikalischen Eigenschaften des applizierten<br />
Reizes assoziiert wurden (Evans, Cui & Starr, 1995; Knott, 1991). Die<br />
Hypothesen bestätigend, ergaben sich für die Amplitude p1 (F = 21,26, df =<br />
1, p = 0,000), die Amplitude n1 (F = 21,52, df = 1, p = 0,000), die Amplitude<br />
p1n1 (F = 38,38, df = 1, p = 0,000), die Amplitude n1p2 (F = 4,01, df =<br />
1, p = 0,045), die Latenzzeit p1 (F = 18,62, df = 1, p = 0,000) und die Latenzzeit<br />
n1 (27,35, df = 1, p = 0,000) signifikante wechselseitige Beziehungen<br />
mit der Einschätzung der Intensität des Geruchs. Für die spätere Komponente<br />
p2 konnten keine entsprechenden Resultate beobachtet werden.
Die Untersuchung<br />
Auch für die Intensität des Brennens ergaben sich in den frühen Komponenten<br />
entsprechende Signifikanzen oder Trends (Amplitude p1: F = 3,67, df =<br />
1, p = 0,056; Amplitude n1: F = 4,77, df = 1, p = 0,029; Amplitude p1n1: F<br />
= 6,71, df = 1, p = 0,01; Latenzzeit p1: F = 9,12, df = 1, p = 0,003; Latenzzeit<br />
n1: F = 11,49, df = 1, p = 0,001). Etwas anders stellte sich das Bild für<br />
die Variable Intensität Stechen dar. Hier waren signifikante Zusammenhänge<br />
eher in den späteren Komponenten zu beobachten (Amplitude n1: F =<br />
8,67, df = 1, p = 0,003; Amplitude p2: F = 4,32, df = 1, p = 0,038; Amplitude<br />
p1n1: F = 5,26, df = 1, p = 0,022; Amplitude n1p2: F = 6,60, df = 1, p =<br />
0,01; Latenzzeit p2: F = 11,28, df = 1, p = 0,001).<br />
6.7.7. Zusammenfassung der Ergebnisse aus der EEG-Untersuchung<br />
In Übereinstimmung mit bereits berichteten Untersuchungen (Kobal &<br />
Hummel, 1988, 1991, 1994; Livermore et al., 1992) lag das olfaktorische<br />
Maximum bei der Amplitude Pz. In trigeminalen Konzentrationen hingegen<br />
bestätigte sich der erwartete Maximalausschlag im Sinne einer starken<br />
Frontalisierung. Auch hier lag dieser unter Pz, allerdings konnte eine Verschiebung<br />
zu Cz beobachtet werden. Nichtraucher zeigten im Vergleich zu<br />
Rauchern hinsichtlich der späten Amplituden eine stärkere Ausprägung,<br />
was entsprechend der Untersuchungen von Becker et al. (1993) und Kobal<br />
et al. (1992) für eine negativere Bewertung der applizierten Reize spricht.<br />
Da in der trigeminalen Amplitude p1 kein Unterschied zu beobachten war,<br />
muss wahrscheinlich ein Deckeneffekt durch die hohen trigeminalen Konzentrationen<br />
angenommen werden, der in allen Untersuchungsgruppen<br />
bereits maximale trigeminale Sensationen ausgelöst hatte und eine ausreichende<br />
Differenzierung nicht mehr ermöglichte. Zudem haben P1-<br />
Amplituden aufgrund ihrer geringen Amplitudengröße einen geringeren<br />
Signal-Rausch-Abstand hinsichtlich der EEG-Grundaktivität. Dies erschwert<br />
eine ausreichende Differenzierung zusätzlich. Raucher und Raucher<br />
im Entzug unterschieden sich in erster Linie ebenfalls hinsichtlich olfaktorischer<br />
später Komponenten, wobei sich die Entzugsgruppe durch höhere<br />
Amplituden auszeichnete. Dies könnte entweder für eine negativere Bewertung<br />
der Einzelreize durch Letztere oder eine veränderte anteriore kortikale<br />
Prozessierung in Folge einer Reizumbewertung im Entzug sprechen. Die<br />
145
146<br />
Die Untersuchung<br />
erneut nicht feststellbaren Differenzen für den trigeminalen Bereich unterstützen<br />
die Annahme eines Deckeneffekts. Hinsichtlich der Latenzzeiten<br />
unterschieden sich die Nichtraucher von den Rauchern vorwiegend durch<br />
geringere Latenzzeiten im trigeminalen Bereich, die jedoch in den explorativen<br />
t-Tests nicht näher differenziert werden konnten. Raucher im Entzug<br />
waren im Vergleich zu ihrem Zustand mit normalem Rauchverhalten in der<br />
späten Komponente p2 durch schnellere Reaktionen gekennzeichnet. Dieser<br />
Trend fiel erneut für die olfaktorischen Anteile deutlich stärker aus als für<br />
die trigeminalen und spricht unter Einbezug der Schwellen für eine Sensiblisierung<br />
der Wahrnehmung trigeminaler Aspekte im Entzug. Lateralisierungstendenzen<br />
waren lediglich für frühe Komponenten bei Rauchern zu<br />
beobachten. Bei Nichtrauchern konnten keine systematischen Unterschiede<br />
zwischen den beiden Ableitepositionen C3 und C4 festgestellt werden. Für<br />
Raucher im Entzug trat jedoch speziell unter S-Nikotin eine umgekehrte<br />
Lateralisierungstendenz für die Amplitude n1 mit Betonung der rechten<br />
Hemisphäre auf. Dies könnte darauf hindeuten, dass mit dem Craving verbundene<br />
Prozesse sich vor allem in der rechten Hirnhälfe niederschlagen.<br />
Dieses Phänomen war jedoch für die anderen Amplituden nicht zu beobachten.<br />
Eine Frontalisierungstendenz konnte lediglich bei Rauchern im Entzug<br />
identifiziert werden. Dabei trat diese Tendenz bei den olfaktorischen Konzentrationen<br />
der beiden Nikotinsorten vorwiegend in den frühen Komponenten<br />
auf, während für die trigeminalen Reizklassen vor allem eine Verschiebung<br />
der späten EEG-Anteile erfolgte. Dieses Ergebnis stützt die These,<br />
dass im Entzug trigeminale Anteile der Nikotinreize sensibler wahrgenommen<br />
werden. Auch unterhalb der Schmerzschwelle ist dieses Phänomen<br />
für diese Substanzen zu beobachten. Außerdem scheinen die trigeminalen<br />
Anteile stärker in Bewertungsprozesse, also in die späten Komponenten<br />
einzufließen, was mit der negativeren Einschätzung aller Reize in Einklang<br />
steht.<br />
Hinsichtlich der trigeminalen Schwellen ergaben sich erwartungsgemäß<br />
höhere Werte für R- Nikotin als für S-Nikotin. Unterschiede zwischen den<br />
Gruppen zeigten sich nur insofern, als Nichtraucher sensibler für die Sensation<br />
Brennen reagierten, während Raucher im Entzug subjektiv empfindlicher<br />
für die stechenden Eigenschaften von S-Nikotin waren. Beide Ergeb-
Die Untersuchung<br />
nisse sprechen wiederum für eine stärkere Bedeutung trigeminaler Anteile<br />
in der Gesamtbewertung des jeweiligen Reizes in der abstinenten Gruppe.<br />
Diese könnten die stärker ausgeprägten Amplitudenausschläge für die<br />
Komponente p2 nach der Applikation von olfaktorischem S-Nikotin und<br />
von trigeminalen Reizen (s. Abbildung 14) bei Entzügigen erklären. Diese<br />
Ergebnisse konnten durch die subjektiven Daten jedoch nur bedingt bestätigt<br />
werden. Die signifikant unangenehmere Bewertung der Reize durch<br />
Nichtraucher unterstützt die eben angeführte Hypothese. Die in den EEG-<br />
Daten zu beobachtenden ähnlich groß ausgeprägten Amplituden bei Rauchern<br />
im Entzug fanden jedoch keine Entsprechung in den subjektiven Hedonik-<br />
und Intensitätsratings. Hier konnten keine Unterschiede im Vergleich<br />
zu der Messung bei normalem Konsumverhalten festgestellt werden.<br />
Ein bemerkenswertes Ergebnis ergab sich bei der Betrachtung der Zusammenhänge<br />
zwischen subjektiv empfundenem Craving und eingeschätzter<br />
Hedonik bei Rauchern und Rauchern im Entzug. Bei beiden Gruppen konnte<br />
ein signifikanter Zusammenhang festgestellt werden. Das Verlangen nach<br />
einer Zigarette stieg an, je angenehmer der Reiz eingeschätzt wurde. Zudem<br />
konnte der inverse Einfluss der hedonischen Einschätzung auf die späte<br />
Komponente p2, wie sie bereits in früheren Untersuchungen postuliert wurde<br />
(Evans, Cui & Starr, 1995; Knott, 1991), bestätigt werden. Ebenso gelang<br />
es, die frühen Komponenten wie erwartet mit physikalischen Eigenschaften<br />
des Reizes in Verbindung zu bringen. Diese Ergebnisse lassen<br />
darauf schließen, dass die Komponente p2 tatsächlich die Kodierung endogener<br />
Prozesse (z.B. Bewertung) widerspiegelt, während die frühen Komponenten<br />
mit den physikalischen Reizeigenschaften in Zusammenhang<br />
stehen. Die Komponente n1 scheint hingegen beide Prozesse wider zu spiegeln.<br />
Die abweichenden Ergebnisse für die Variable Intensität Stechen, die<br />
deutlicher mit späteren Komponenten korrelierte, deuten darauf hin, dass<br />
die Empfindung Stechen mit einer späten kortikalen Prozessierung einhergeht.<br />
Signifikante Zusammenhänge traten außerdem zwischen Craving und<br />
verkürzten Latenzzeiten auf. Dieses Ergebnis unterstützt deren Bedeutung<br />
für das Verlangen zu Rauchen.<br />
147
148<br />
6.8. fMRT-Untersuchung<br />
Die Untersuchung<br />
6.8.1. Stichprobe der fMRT-Untersuchung<br />
Die Auswahl der Probanden erfolgte analog zur Stichprobenbildung der<br />
EEG-Untersuchung. Auch hier wurden 30 Studenten in die Untersuchung<br />
eingeschlossen, von denen 15 Nichtraucher und 15 Raucher waren. In jeder<br />
Untersuchungsgruppe befanden sich ebenfalls acht weibliche und sieben<br />
männliche Teilnehmer. Der Altersdurchschnitt der Experimentalgruppe lag<br />
bei 25,67 Jahren (Minimum: 22 Jahre, Maximum: 30 Jahre), in der Kontrollgruppe<br />
bei 25,87 Jahren (Minimum: 21 Jahre, Maximum: 29 Jahre).<br />
6.8.2. Darstellung des Untersuchungsablaufs<br />
Zur Applikation der Geruchsreize wurde ein spezielles fMRT-taugliches<br />
Olfaktometer des Typs OL016 (Firma Burghart Messtechnik GmbH, Wedel,<br />
Deutschland) eingesetzt, das nach dem gleichen grundlegenden Prinzip<br />
funktioniert wie das in Kapitel 6.2.1. bereits dargestellte. Der elementare<br />
Unterschied besteht in einem längeren Transportschlauch zur Nase des<br />
Probanden, da sich das Gerät außerhalb des MRI-Scannerraums befinden<br />
muss und einem Messingendstück, welches die Magnetfelder des Scanners<br />
nicht beeinträchtigt. Durch den längeren Schlauch erhöht sich die Zeit der<br />
Verzögerung, bis der Geruch den Transportschlauch verlässt und die Nase<br />
des Probanden erreicht, auf ca. 80-100ms. Das Olfaktometer ist in Abbildung<br />
22 zu sehen.
Die Untersuchung<br />
Abbildung 22: Aufbau des fMRT-tauglichen Olfaktometers<br />
Der Olfaktometerschlauch wurde mit einer Spezialvorrichtung an der Scannertrage<br />
fixiert. So konnte verhindert werden, dass sich der Messingendkopf<br />
durch Bewegungen des Probanden (z.B. durch Atembewegungen) bewegt<br />
und Artefakte erzeugt. Außerdem erfolgte die Instruktion, sich während der<br />
Messung so wenig wie möglich zu bewegen. Die experimentelle Anordnung<br />
kann der Abbildung 23 entnommen werden.<br />
149
150<br />
Die Untersuchung<br />
Abbildung 23: Experimentelle Anordnung der funktionellen Magnetresonanztomographie<br />
Während der Untersuchung lagen die Probanden in Rückenlage mit dem<br />
Kopf voran im Tomographen auf einer fahrbaren Scannertrage. Im Bereich<br />
des Kopfes wurde eine Magnetspule angebracht. So konnten Kopfbewegungen<br />
gering gehalten werden, welche Korrekturen in den aufgezeichneten<br />
Bildern erforderlich gemacht hätten. Jede fMRT-Sitzung bestand analog zur<br />
EEG-Untersuchung aus einer olfaktorischen Schwellenbestimmung, einer<br />
olfaktorischen und einer trigeminalen Sequenz (s. Kap. 6.7.2.).<br />
Die Stimulation mit Nikotin erfolgte jeweils nach einem event-related-<br />
Design. In der olfaktorischen Sequenz wurde wie bereits in der EEG-<br />
Untersuchung neben S- und R-Nikotin in jeweils individuell bestimmter<br />
olfaktorischer, schwellennaher Konzentration ein Rosengeruch mit 2,4<br />
l/min als Kontrollreiz eingesetzt, wobei jede Reizklasse in pseudorandomisierter<br />
Reihenfolge fünfmal appliziert wurde. Die trigeminale Serie bestand<br />
aus jeweils vier S- und R-Nikotinreizen in trigeminaler Konzentration mit 8<br />
l/min und Kohlenstoffdioxid mit einem Fluss von 4,8 l/min als Kontrollreiz.
Die Untersuchung<br />
Alle applizierten Stimuli dauerten 250ms und wurden auch hier in einer<br />
pseudorandomisierter Reihenfolge dargeboten. Zur Vermeidung von Habituationseffekten<br />
wurde mit einem Interstimulusintervall von 90s gearbeitet.<br />
Die Anzahl der Reize in den jeweiligen Sequenzen reichte aus, um ein akzeptables<br />
Signal-Rausch-Verhältnis im fMRT-Signal zu erzielen. Zusätzlich<br />
konnte durch das große Stimulusintervall eine mögliche Ansammlung von<br />
Nikotin an der nasalen Mucosa und eine potentielle zeitliche Summation an<br />
den Rezeptoren verhindert werden. In der olfaktorischen Sequenz konnte so<br />
die Möglichkeit des Auftretens trigeminaler Effekte ebenfalls minimiert<br />
werden (Cometto-Muniz et al., 2004). Jede fMRT-Untersuchung bestand<br />
somit aus insgesamt 27 Geruchsreizen. Die Abfolge der Reize in der olfaktorischen<br />
und der trigeminalen Sequenz können der Tabelle 14 entnommen<br />
werden.<br />
olfaktorisch trigeminal<br />
R-Nikotin CO2<br />
Rose R-Nikotin<br />
Rose R-Nikotin<br />
S-Nikotin S-Nikotin<br />
R-Nikotin CO2<br />
S-Nikotin S-Nikotin<br />
S-Nikotin S-Nikotin<br />
Rose R-Nikotin<br />
R-Nikotin CO2<br />
R-Nikotin CO2<br />
Rose S-Nikotin<br />
S-Nikotin R-Nikotin<br />
Rose<br />
R-Nikotin<br />
S-Nikotin<br />
Tabelle 14: Abfolge der Reize in der olfaktorischen und trigeminalen Sequenz in der fMRT-<br />
Untersuchung<br />
In Abbildung 24 und 25 sind die Stimulusprotokolle der olfaktorischen und<br />
trigeminalen Sequenzen dargestellt, die für alle Serien identisch waren.<br />
Senkrechte Balken kennzeichnen jeweils die Gabe eines Reizes (grün: S-<br />
Nikotin, blau: R-Nikotin, grau: Rose bzw. CO2). Die korrekte Abfolge der<br />
Stimuli wurde auf einem Monitor verfolgt.<br />
151
152<br />
Die Untersuchung<br />
Abbildung 24: Stimulationsprotokoll der olfaktorischen Sequenz<br />
Abbildung 25: Stimulationsprotokoll der trigeminalen Sequenz<br />
Zusätzlich zu den fMRT-Daten wurden auch in diesem Teil der Untersuchung<br />
für jeden applizierten Reiz mit Hilfe einer elektronischen visuellen<br />
Analogskala verschiedene psychophysische Daten erhoben. Da der Monitor<br />
aufgrund des magnetischen Felds nicht im Untersuchungsraum platziert<br />
werden konnte, wurde eine spezielle Versuchanordnung gewählt, mit deren<br />
Hilfe dem Probanden über einen Spiegel neben der Ratingskala Symbole<br />
dargeboten wurden, deren Zuordnung zu den einzelnen Psychophysikabfragen<br />
sie vor der Untersuchung gelernt hatten. Auch hier wurden die Geruchsintensität<br />
der Reize, die Intensität des Brennens, die Intensität des Stechens,<br />
die Hedonik und das aktuelle Verlangen zu Rauchen (Craving) eingeschätzt.<br />
Die Angaben der Raucher in den beiden Untersuchungsbedingungen Rauchen<br />
und im Entzug wurden wiederum durch Kohlenmonoxidanalysen und<br />
die Entnahme einer Blutprobe überprüft.<br />
6.8.3. Auswertung der funktionellen Bilddaten<br />
Zunächst war eine Reihe von Vorverarbeitungsschritten erforderlich, um die<br />
als Bildvolumen resultierenden Datensätze einer statistischen Auswertung<br />
unterziehen zu können. Die Bilddaten wurden mit Hilfe des Programms<br />
Brain Voyager QX (Version 2.6, Brain Innovation, Maastricht, Niederlande)<br />
analysiert, dass Algorithmen für die Vorverarbeitung und die statistische
Die Untersuchung<br />
Auswertung zur Verfügung stellt. Ein Ausschluss weiterer Daten war nicht<br />
erforderlich, da bereits bei der Aufnahme der funktionellen Bilder die ersten<br />
drei Volumen verworfen wurden. Dieser Schritt diente dazu, Spinsättigungseffekte<br />
zu vermeiden. Diese treten auf, wenn stationäre Spins in der Gewebsschicht<br />
durch multiple Hochfrequenzimpulse Artefakte in den Bildaufnahmen<br />
erzeugen, obwohl sie nur sehr wenig zum Signal beitragen (Joarder<br />
& Gedroyc, 2001). Um tatsächlich nur den Einfluss der ungesättigten Spins<br />
im fließenden Blut erfassen zu können, muss das stationäre Gewebe mit<br />
Voraufnahmen zunächst gesättigt werden, um unverfälschtes Datenmaterial<br />
zu erhalten.<br />
Vorverarbeitung der funktionellen Bilddaten<br />
In dieser Untersuchung konnten die Kopfbewegungen der Probanden durch<br />
die gute Fixierung des Kopfes und die hohe Motivation der Teilnehmer<br />
zwar weitgehend minimiert werden, es konnte jedoch nicht davon ausgegangen<br />
werden, dass überhaupt keine Veränderung der Kopfposition erfolgte.<br />
Da für die statistische Auswertung jedoch eine möglichst stabile Zuordnung<br />
eines Voxels zu einem bestimmten Bereich des Gehirns notwendig ist,<br />
wurde zunächst eine Bewegungskorrektur durchgeführt. In diesem Schritt<br />
erfolgte eine automatische Ausrichtung aller Bildvolumina an anatomischen<br />
Referenzpunkten der ersten Aufnahme der jeweiligen fMRT-Sequenz. Diese<br />
Korrektur geschah durch Translation in den drei Raumrichtungen und<br />
durch Rotation anhand der drei Raumachsen, um Unterschiede zwischen<br />
den Bildern zu minimieren. Weiterhin erfolgte eine slice scan time correction,<br />
eine so genannte Zeitkorrektur, bei der eine Anpassung der linearen<br />
Trendverschiebung der Aktivierungskurven innerhalb der Repetitionszeit<br />
(TR) durchgeführt wird. Zudem wurden die Daten mit einem Hochpassfilter<br />
von fünf Zyklen pro Zeitserie frequenzbasiert gefiltert (Fast-Fourier-<br />
Transformation). Um Aussagen über Hirnaktivierungen eines Probandenkollektivs<br />
machen zu können, mussten hirnanatomische Variabilitäten durch<br />
eine räumliche Normalisierung standardisiert werden. Die funktionellen<br />
Datensätze jedes Probanden wurden hierbei in den Talairach-Raum (Talairach<br />
& Tournoux, 1988) transformiert, was zu einer 4-D-<br />
Datensatzrepräsentation (Raum und Zeit) führte. Dabei werden Unterschiede<br />
zwischen dem Gehirn eines Einzelprobanden und einem Standardhirn<br />
153
154<br />
Die Untersuchung<br />
minimiert. Mit Hilfe einer räumlichen Glättung wurde außerdem das Signal-<br />
Rausch-Verhältnis des fMRT-Signals verbessert. Während dieses Prozesses<br />
werden benachbarte Voxel räumlich zusammengefasst, um hochfrequentes<br />
Rauschen zu unterdrücken. Durch die produzierte Unschärfe des Bildes<br />
können trotz Normalisierung verbliebene Unterschiede zwischen den Einzelgehirnen<br />
ausgeglichen und geringfügig örtlich variierende Aktivierungen<br />
dennoch identifiziert werden.<br />
Vorverarbeitung des anatomischen Projektes<br />
Da die funktionellen Bilder beim Echo-Planar-Imaging eine vergleichsweise<br />
geringe anatomische Auflösung besitzen, wurde in dieser Studie zusätzlich<br />
eine hoch aufgelöste anatomische Aufnahme, eine MPRAGE (magnetization<br />
prepared rapid gradient echo) gemacht. Dabei handelt es sich um<br />
eine Bildersequenz aus 160 sagittalen Aufnahmen mit einer Auflösung von<br />
256x256 Pixeln und einer Dicke von einem Millimeter. Aus diesen Daten<br />
wurde ein dreidimensionaler Datensatz generiert, der ebenfalls zur Standardisierung<br />
einer Talairach-Transformation unterzogen wurde. Erst nach diesem<br />
Schritt ist es möglich, ein einheitliches Koordinatensystem auf die<br />
vorher individuell unterschiedlichen Gehirne anwenden zu können. Von<br />
entscheidender Bedeutung sind dabei die beiden Fixpunkte Comissura anterior<br />
(AC) und Comissura posterior (PC), die neben einigen anderen wichtigen<br />
anatomischen Punkten bei jeder einzelnen Probandenaufnahme definiert<br />
werden müssen. So kann sichergestellt werden, dass sich gleiche morphologische<br />
Bereiche verschiedener Gehirne bei den selben Koordinaten<br />
befinden. Jede funktionelle Sequenz wurde im Anschluss, ähnlich wie bei<br />
der Bewegungskorrektur, mit dem anatomischen Datensatz mittels Reorientierung<br />
koregistriert.<br />
Statistische Auswertung<br />
Die statistische Auswertung wurde für jedes Voxel 10 separat durchgeführt.<br />
Die Einzelanalysen der Bilddaten erfolgten unter Verwendung des allge-<br />
10 Mit einem Voxel ist das dreidimensionale Äquivalent eines Pixels gemeint, das einem diskreten<br />
Wert an einer kartesischen xyz-Koordinate des Datensatzes entspricht.
Die Untersuchung<br />
meinen linearen Modells (General Linear Model, GLM). Dabei wurden die<br />
gemessenen Aktivitäten in einem Voxel durch eine gewichtete Summe von<br />
vorhersagbaren Variablen erklärt. Die errechneten Regressionsgewichte<br />
minimierten den Fehler zwischen vorhergesagten und tatsächlichen Werten.<br />
Eine erstellte Designmatrix umfasste neben diesen Parametern auch die<br />
zeitliche Abfolge der Stimulationsbedingungen und der Baseline während<br />
der einzelnen Sequenzen. Es handelte sich um ein „event-related“-Design,<br />
in dem die verschiedenen Geruchsklassen als einzelne Events bzw. Prädiktoren<br />
spezifiziert wurden. In der vorliegenden Untersuchung resultierten für<br />
jede funktionelle Sequenz entsprechend drei Events. Für die olfaktorische<br />
Abfolge waren dies „olfaktorisches S-Nikotin“, „olfaktorisches R-Nikotin“<br />
und „Rose“, für die trigeminale Version „trigeminales S-Nikotin“, „trigeminales<br />
R-Nikotin“ und „CO2“. Durch die Einführung dieser Prädiktoren<br />
konnte sichergestellt werden, dass bei der Auswertung nur Hirnaktivierungen<br />
berücksichtigt wurden, die auch tatsächlich durch den jeweiligen Reiz<br />
ausgelöst wurden. Gleichzeitig bestand auch die Möglichkeit, den Einfluss<br />
verschiedener Events durch die Einbeziehung zweier Prädiktoren in die<br />
Analyse einander gegenüberzustellen und einen so genannten geplanten<br />
Kontrast zu berechnen. So war es möglich, im direkten Vergleich den dominanteren<br />
Einflussfaktor auf die jeweilige Hirnregion zu identifizieren.<br />
Unter Einbeziehung einer hämodynamischen Modellierung (HRF-Kurve)<br />
resultierten in einem ersten Schritt die geschätzten Parameter für die einzelnen<br />
Bedingungen der Designmatrix. Sowohl die Analysen der einzelnen<br />
Events als auch die Berechnung unterschiedlicher Kontraste erfolgte mit<br />
Hilfe von t-Tests. Positive resultierende t-Werte zeigen einen positiven<br />
Zusammenhang zwischen dem Prädiktor und dem so genannten BOLD-<br />
Signal 11 an, negative entsprechend eine inverse Relation. Bei Vorliegen<br />
einer genauen anatomischen Hypothese über den Ort der Aktivierung - also<br />
der Auswertung der so genannten Regions of Interest - wurde unter Einbeziehung<br />
aller 45 Probanden eine für multiple statistische Tests korrigierte<br />
11 Mit der Blood Oxygen Level Dependency (BOLD) wird ein physikalischer Effekt bezeichnet.<br />
Durch die gestiegene elektrochemische Aktivität der Gehirnzellen eines Areals steigt dort<br />
auch der Bedarf an Sauerstoff und Glukose. Die dadurch hervorgerufenene Veränderungen des<br />
Blutflusses und der Sauerstoffsättigung des Blutes spiegeln sich als Veränderungen des lokalen<br />
Magnetfeldes im sogenannten BOLD-Signal wider (Stöcker & Shah, 2007).<br />
155
156<br />
Die Untersuchung<br />
Signifikanzschwelle von p ≤ 0.05 eingesetzt (trigeminal: FDR-<br />
Korrektur 12 /olfaktorisch: Bonferroni- bzw. FWE-Korrektur). Für nicht erwartete<br />
Veränderungen im Gehirn wurde unter Anwendung der genannten<br />
Korrekturverfahren eine Signifikanzschwelle von p ≤ 0.001 gewählt. Die<br />
korrigierten Schwellenwerte besitzen die höchste statistische Güte für den<br />
Ausschluss falsch positiv aktivierter Voxel. Bei Gruppenvergleichen bzw.<br />
dem Vergleich der Aktivierungsmuster einzelner Reizklassen untereinander<br />
konnten jedoch aufgrund der Stichprobengrößen jeweils nur 15 Probanden<br />
in die Auswertung mit eingeschlossen werden, so dass eine entsprechende<br />
Korrektur aufgrund der geringen Fallzahl nicht möglich war. In diesen Fällen<br />
wurde für die Regions of Interest eine unkorrigierte Schwelle von p ≤<br />
0.05, für weitere aktivierte Regionen eine unkorrigierte Signifikanzschwelle<br />
von p ≤ 0.001 gewählt. Aktivierungsmuster, die weniger als drei Voxel<br />
umfassten, wurden in der Analyse grundsätzlich nicht berücksichtigt.<br />
Bei der Auswertung wurden vorwiegend Gruppenanalysen durchgeführt,<br />
bei denen die transformierten Daten der Einzelpersonen überlagert, gemittelt<br />
und auf ein anatomisches Standardgehirn übertragen wurden. Lediglich<br />
bei der Prüfung von Zusammenhängen zwischen Aktivierungen und subjektiven<br />
Ratings wurden die Einzeldaten der Probanden herangezogen.<br />
6.8.4. Ergebnisse der Auswertung der fMRT-Daten<br />
Aktivierungen nach Applikation olfaktorischer bzw. niedrig dosierter Reize<br />
Bevor die Einzelhypothesen dieser Studie näher untersucht wurden, sollte<br />
zunächst überprüft werden, ob die durch olfaktorische bzw. trigeminale<br />
Reize aktivierten Hirnregionen mit bereits bekannten Voruntersuchungen in<br />
Einklang standen. Dazu wurden die Reaktionen auf die einzelnen Substanzklassen<br />
über alle Untersuchungsteilnehmer hinweg betrachtet. Für den Geruch<br />
Rose, der wie bereits erwähnt als rein olfaktorischer Stimulus betrach-<br />
12 Die Methode der false discovery rate (FDR) wird auch als Sicherheit der Vorhersage bezeichnet.<br />
Sie findet bei mulitplen Testungen eine Reihe von Aktivierungen, die als Abweichungen<br />
von der Nullhypothese der Gleichheit definiert sind. Dabei werden einige falschpositive<br />
Tests zugelassen. Wenn deren Anzahl klein im Verhältnis zur Gesamtzahl der positiven<br />
Tests ist (Wohlschläger, Kellermann & Habel, 2007).
Die Untersuchung<br />
tet wird, fanden sich in Übereinstimmung mit Boyle, Heinke, Gerber, Frasnelli<br />
und Hummel (2007), Heinke (2008), Hummel et al. (2005) und Iannilli,<br />
del Gratta, Gerber, Romani und Hummel (2008) Aktivierungen bilateral<br />
in der Amygdala, im orbitofrontalen Kortex und in der Insula. Im piriformen<br />
Kortex hingegen konnte für Rose kein BOLD-Signal detektiert werden.<br />
Die Reaktionsmuster unter S- und R-Nikotin fielen im Wesentlichen identisch<br />
aus, jedoch zeigten sich hier Aktivierungen im linken piriformen Kortex.<br />
Zusätzlich zu den Regions of Interest fanden sich noch weitere Regionen,<br />
die gemeinsam mit erstgenannten der Tabelle 15 entnommen werden<br />
können.<br />
157
158<br />
Die Untersuchung<br />
Anatomische Region Talairach-Koordinaten<br />
links<br />
Regions of Interest<br />
Talairach-Koordinaten<br />
rechts<br />
Amygdala -22 -13 -12 23 -13 -12<br />
Inferiorer frontaler Gyrus -49 -40 7 43 26 7<br />
Medialer frontaler Gyrus -2 19 49 2 -8 52<br />
Mittlerer frontaler Gyrus -32 -6 61 - - -<br />
Insula -36 -7 16 51 -38 24<br />
Piriformer Kortex 13 -23 -28 -4 - - -<br />
Weitere Regionen<br />
Anteriores Cingulum -3 36 21 5 44 6<br />
Cerebellum -5 -55 -15 25 -55 -24<br />
Cuneus -1 -68 9 2 -78 9<br />
Lingualer Gyrus -2 79 -6 1 -69 3<br />
Lobulus parietalis inferior -52 -42 38 61 -26 24<br />
Mittlerer temporaler Gyrus - - - 57 -33 4<br />
Nucleus caudatus -8 7 7 7 4 8<br />
Postzentraler Gyrus -33 -24 43 59 -23 15<br />
Präzentraler Gyrus -35 -19 44 58 -1 17<br />
Superiorer frontaler Gyrus - - - 61 -7 5<br />
Superiorer temporaler Gyrus - - - 5 7 64<br />
Supramarginaler Gyrus -47 -38 31 59 -37 29<br />
Thalamus -3 -18 8 5 -18 7<br />
Tabelle 15: Aktivierte Hirnregionen nach der Applikation olfaktorischer Reize<br />
13 Diese Region war nur unter S-(-)- und R-(+)-Nikotin aktiviert.
Die Untersuchung<br />
Insgesamt betrachtet, reagierten die einzelnen Hirnregionen in den meisten<br />
Fällen am stärksten auf S-Nikotin. R- Nikotin löste die kleinsten BOLD-<br />
Signale aus (z.B. im inferioren, mittleren und superioren frontalen Gyrus,<br />
im Cerebellum, im Nucleus caudatus, im supramarginalen Gyrus und in der<br />
Insula). Die unter S-Nikotin gefundenen Areale decken sich im Wesentlichen<br />
mit den Ergebnissen von Albrecht (2008). Jedoch fanden sich auch<br />
hier zusätzlich aktivierte Areale im Nucleus caudatus, im anterioren Cingulum,<br />
im Cuneus, sowie im Temporallappen (mittlerer und superiorer temporaler<br />
Gyrus links). In Abbildung 26 sind beispielhaft Aktivierungen nach<br />
der Applikation olfaktorischer Reize zu sehen.<br />
Abbildung 26: Aktivierungen nach Applikation olfaktorischer Reize (Bonferoni-korrigiert, p ≤<br />
0.001)<br />
Erste Reihe (linke Hemisphäre, sagittal): linkes Bild: postzentraler Gyrus, präzentraler Gyrus,<br />
supramarginaler Gyrus, Lobulus parietalis inferior; zweites Bild: Insula, superiorer temporaler<br />
Gyrus, postzentraler Gyrus; drittes Bild: Cerebellum; rechtes Bild: superiorer frontaler Gyrus,<br />
medialer frontaler Gyrus, Nucleus Caudatus, lingualer Gyrus, Cuneus; Zweite Reihe (rechte<br />
Hemisphäre, sagittal): linkes Bild: anteriores Cingulum, Thalamus, Cuneus, lingualer Gyrus,<br />
medialer frontaler Gyrus; zweites Bild: Nucleus Caudatus, Thalamus, lingualer Gyrus; drittes<br />
Bild: Cerebellum; rechtes Bild: präzentraler Gyrus, Lobulus parietalis inferior<br />
159
160<br />
Die Untersuchung<br />
Aktivierungen nach Applikation trigeminaler bzw. hoch dosierter Reize<br />
Auch im trigeminalen Bereich wurden die BOLD-Signale des Gehirns in<br />
Reaktion auf die einzelnen Reizklassen über alle 45 Versuchspersonen<br />
hinweg untersucht. Ebenfalls in Übereinstimmung mit Boyle et al. (2007),<br />
Heinke (2008), Hummel et al. (2005) und Iannilli et al. (2008) konnten für<br />
den rein trigeminalen Reiz CO2 im rechten Cerebellum, in der linken Insula,<br />
im rechten orbitofrontalen Gyrus, bilateral im piriformen Kortex, bilateral<br />
im postzentralen Gyrus und im linken Thalamus gefunden werden. Eine<br />
Deaktivierung zeigte sich in der rechten Insula. Auch hier fand sich im<br />
anterioren Cingulum ein zusätzliches Areal, das auf die Applikation von<br />
CO2 reagierte und gemeinsam mit den Regions of Interest der Tabelle 16<br />
entnommen werden kann.<br />
Anatomische Region<br />
Regions of Interest<br />
Talairach-Koordinaten<br />
links<br />
Talairach-Koordinaten<br />
rechts<br />
Cerebellum - - - 42 -52 -41<br />
Mittlerer frontaler Gyrus - - - 35 58 0<br />
Medialer frontaler Gyrus -22 27 24 - - -<br />
Insula -45 -12 8 40 -35 22<br />
Piriformer Kortex -24 -28 -5 24 -28 -5<br />
Postzentraler Gyrus -29 -40 68 31 -31 67<br />
Thalamus -7 -16 8 - - -<br />
Weitere Regionen<br />
Anteriores Cingulum - - - 20 37 4<br />
Tabelle 16: Signifikante BOLD-Signale nach Applikation von CO2 (Deaktivierungen sind<br />
kursiv und dick gedruckt)
Die Untersuchung<br />
Anders als im olfaktorischen Bereich unterschied sich das trigeminale Aktivierungsmuster<br />
unter Nikotin von dem des Kontrollreizes. Statt einer Aktivierung<br />
im rechten Cerebellum zeigte sich eine Deaktivierung im linken<br />
Cerebellum. Auch in der linken Insula trat kein Signal auf, hingegen reagierte<br />
der linke orbitofrontale Gyrus statt einer Aktivierung mit einer Deaktivierung.<br />
Im rechten orbitofrontalen Gyrus zeigte sich lediglich eine Aktivierung<br />
unter S-Nikotin, nicht jedoch nach der Applikation des anderen<br />
Enantiomers. Im piriformen Kortex konnte unter beiden Isomeren kein<br />
Signal detektiert werden. Im linken postzentralen Gyrus hingegen reagierte<br />
das Gehirn nur auf R-Nikotin, während rechtsseitig unter beiden eine Aktivierung<br />
zu beobachten war. Wiederum anders als bei CO2 konnten bilaterale<br />
Deaktivierungen im präzentralen Gyrus gefunden wurden, eine Antwort des<br />
linken Thalamus war hingegen nicht zu beobachten. Stattdessen trat eine<br />
Deaktivierung im rechten Thalamus auf. Die gefundenen Aktivierungsmuster<br />
decken sich ebenfalls im Wesentlichen mit den bereits von Albrecht<br />
(2008) berichteten. Eine Übersicht der durch die beiden Nikotinsorten aktivierten<br />
Hirnareale findet sich in Tabelle 17.<br />
161
162<br />
Die Untersuchung<br />
Anatomische Region Talairach-Koordinaten links Talairach-Koordinaten<br />
Regions of Interest<br />
rechts<br />
Cerebellum -23 -49 -32 - - -<br />
Mittlerer frontaler Gyrus 14 -2 69 6 35 58 0<br />
Medialer frontaler Gyrus 12<br />
-22 27 24 - - -<br />
Insula - - - 40 -35 22<br />
Präzentraler Gyrus -29 6 26 43 19 40<br />
Postzentraler Gyrus 15 -29 -40 68 31 -31 67<br />
Thalamus - - - 18 -12 7<br />
Weitere Regionen<br />
Anteriores Cingulum 12<br />
- - - 20 37 4<br />
Cingulum - - - 24 -42 27<br />
Lobulus parietalis inferior -54 -63 40 - - -<br />
Precuneus - - - 43 -74 39<br />
Superiorer frontaler Gyrus - - - 36 52 20<br />
Tabelle 17: Signifikante BOLD-Signale nach Applikation von trigeminalem S- und R-Nikotin<br />
(Deaktivierungen sind kursiv und dick gedruckt)<br />
Beispielhaft können auch für die Applikation trigeminaler Reize aktivierte<br />
Hirnareale der Abbildung 27 entnommen werden.<br />
14<br />
Rechtshemisphärisch war nur eine Aktivierung oder Deaktivierung unter S-(-)-Nikotin zu<br />
beobachten.<br />
15<br />
Linkshemisphärisch war nur eine Aktivierung oder Desktivierung unter R-(+)-Nikotin zu<br />
beobachten.
Die Untersuchung<br />
Abbildung 27: Aktivierungen nach Applikation trigeminaler Reize (FDR-korrigiert, p ≤ 0.001)<br />
Erste Reihe (coronar): linkes Bild: rechter postzentraler Gyrus, rechtes Cingulum; zweites Bild:<br />
linker mittlerer frontaler Gyrus, linker präzentraler Gyrus; drittes Bild: rechter mittlerer frontaler<br />
Gyrus, rechter präzentraler Gyrus, rechter superiorer frontaler Gyrus, linker mittlerer frontaler<br />
Gyrus; rechtes Bild: rechtes anteriores Cingulum; Zweite Reihe (transversal): linkes Bild:<br />
rechte Insula, rechter mittlerer frontaler Gyrus, rechtes Cingulum, linker medialer frontaler<br />
Gyrus; zweites Bild: rechtes anteriores Cingulum; drittes Bild: rechter präzentraler Gyrus,<br />
rechter Precuneus, linker präzentraler Gyrus; rechtes Bild: rechter mittlerer frontaler Gyrus,<br />
linker mittlerer frontaler Gyrus<br />
Unterschiede in der Wahrnehmung von S-Nikotin bei Rauchern und Nichtrauchern<br />
Da die Raucher in dieser Untersuchung entsprechend der Einschlusskriterien<br />
tagtäglich mit S-Nikotin in Kontakt waren und entsprechende Konditionierungsmechanismen<br />
postuliert werden können (s. Kap. 3.4.1.), lautete<br />
die erste Hypothese, dass es im Vergleich mit Nichtrauchern zu veränderten<br />
Reaktionen des Gehirns kommt. Zur Überprüfung wurde mit Hilfe des Programms<br />
BrainVoyager ein Kontrast eingesetzt, der den Vergleich der beiden<br />
Gruppen ermöglichte.<br />
Entsprechend der Hypothese traten in der niedrigen Konzentration des S-<br />
Nikotins verschiedene signifikante Unterschiede auf. Nichtraucher reagier-<br />
163
164<br />
Die Untersuchung<br />
ten mit stärkeren Aktivierungen bilateral in der Amygdala, im anterioren<br />
Cingulum, im Cerebellum, im Claustrum, im fusiformen Gyrus, im Hirnstamm,<br />
im inferioren frontalen Gyrus, im inferioren temporalen Gyrus, in<br />
der Insula, im Lobulus paracentralis, im Lobulus parietalis inferior, im medialen<br />
frontalen Gyrus, im mittleren frontalen Gyrus, im mittleren okzipitalen<br />
Gyrus, im mittleren temporalen Gyrus, im Nucleus accumbens (ventrales<br />
Striatum), im parahippocampalen Gyrus, im posterioren Cingulum, im<br />
postzentralen Gyrus, im präzentralen Gyrus, im Putamen (dorsales Striatum),<br />
im superioren temporalen Gyrus und im Thalamus. Linskhemisphärisch<br />
war der gleiche Effekt im Cuneus, im Hippocampus und im Lobulus<br />
parietalis superior zu beobachten, während rechtshemisphärisch der linguale<br />
Gyrus, der Precuneus und der supramarginale Gyrus stärkere BOLD-<br />
Signale aussendeten.<br />
In den hohen Konzentrationen hingegen trat eine stärkere Aktivierung im<br />
rechten mittleren frontalen Gyrus bei Rauchern auf. Weitere Unterschiede<br />
zwischen den beiden Untersuchungsgruppen waren nicht zu beobachten.<br />
Unterschiede in der Wahrnehmung von S- und R-Nikotin<br />
Zur Überprüfung der Hypothese, dass Raucher aufgrund von Konditionierungsprozessen<br />
durch Vorerfahrungen mit S-Nikotin (s. Kap. 3.4.1.) unterschiedlich<br />
auf die beiden Nikotinenantiomere reagieren, wurden die Aktivierungsmuster<br />
in Folge der Applikation beider Isomere pro Untersuchungsgruppe<br />
getrennt analysiert. Dazu wurde ein Kontrast verwendet, der<br />
einen direkten Vergleich ermöglicht.<br />
Bei Nichtrauchern wurden signifikant unterschiedlich ausgeprägte Reaktionen<br />
für die beiden Substanzen in olfaktorischer Konzentration jeweils<br />
linkshemisphärisch im Claustrum, im Hirnstamm, im inferioren frontalen<br />
Gyrus, im medialen frontalen Gyrus, im mittleren frontalen Gyrus und im<br />
Thalamus, sowie bilateral im präzentralen Gyrus und im Putamen identifiziert.<br />
Dabei hatte in allen Fällen S-Nikotin den dominanteren Einfluss, führte<br />
also zu stärkeren Aktivierungen. Trigeminal traten signifikant stärkere<br />
Aktivierungen unter S-Nikotin im rechten Lobulus paracentralis und nach
Die Untersuchung<br />
der Gabe von R-Nikotin im rechten Thalamus auf. Im rechten Putamen<br />
hingegen bewirkte R-Nikotin eine stärkere Deaktivierung.<br />
Bei Rauchern zeigten sich im direkten Vergleich der olfaktorischen Reizklassen<br />
lediglich signifikant stärkere Aktivierungen nach der Applikation<br />
von S-Nikotin im linken mittleren frontalen Gyrus und im rechten präzentralen<br />
Gyrus. Im trigeminalen Bereich waren unter R-Nikotin die Aktivierung<br />
in der rechten Amygdala und die Deaktivierung im rechten anterioren<br />
Cingulum dominanter ausgeprägt. In Reaktion auf S-Nikotin war eine<br />
signifikant stärkere Deaktivierung im linken präzentralen Gyrus zu beobachten.<br />
Auch bei Rauchern im Entzug war das Aktivierungsmuster anders ausgeprägt<br />
als bei Nichtrauchern. Im olfaktorischen Bereich zeigte sich ein signifikant<br />
dominanterer Einfluss des R-Nikotins auf die Aktivierungen im rechten<br />
Hippocampus und im linken Thalamus, das S-Nikotin aktivierte hingegen<br />
den linken Nucleus accumbens und das linke Putamen signifikant stärker.<br />
In den trigeminalen Konzentrationen führte R-Nikotin zu einem signifikant<br />
positiveren BOLD-Signal im linken Nucleus accumbens, eine größere<br />
Deaktivierung unter S-Nikotin zeigte sich im linken präzentralen Gyrus.<br />
In Abbildung 28 ist exemplarisch der über alle Probanden gemittelte Verlauf<br />
des BOLD-Signals beider Isomere in olfaktorischer Konzentration im<br />
rechten Hippocampus zu sehen.<br />
Abbildung 28: Gemittelter BOLD-Verlauf im rechten Hippocampus bei Rauchern im Entzug<br />
nach der Applikation von R-Nikotin (blau) und S-Nikotin im Vergleich 16<br />
16 Die senkrechten Linien kennzeichnen den Zeitraum nach Reizapplikation, der für die Analy-<br />
se als relevant definiert wurde.<br />
165
166<br />
Die Untersuchung<br />
Die im Vergleich mit Nichtrauchern bei Rauchern im Entzug beobachteten<br />
geringer ausgeprägten Unterschiede zwischen den beiden Enantiomeren in<br />
den typischen olfaktorischen und mit Schmerz assoziierten Hirnarealen<br />
könnten als Ergebnis einer Generalisierung von bereits mit S-Nikotin erfolgten<br />
Konditionierungsprozessen auf R-Nikotin gewertet werden. Als<br />
Folge wäre eine sensiblere Wahrnehmung von trigeminalen Eigenschaften<br />
und eine damit einhergehende verringerte olfaktorische und trigeminale<br />
Differenzierungsfähigkeit der beiden Isomere durch die Entzugsgruppe<br />
denkbar. Dieser Effekt schien zumindest im trigeminalen Bereich stark<br />
ausgeprägt zu sein. Im Gegensatz zu Rauchern im Entzug könnte in der<br />
aktuell rauchenden Gruppe durch den anhaltenden und regelmäßigen Kontakt<br />
eine Habituation eingetreten sein, die sich auch auf andere trigeminale<br />
Reize auswirkt. Nichtraucher konnten hingegen die beiden Nikotinsorten<br />
hinsichtlich ihrer olfaktorischen Komponenten besser trennen. Diese Vermutung<br />
wird auch durch die Ergebnisse aus dem vorangegangenen Kapitel<br />
gestützt.<br />
Hingegen könnten die unterschiedlichen Aktivierungsmuster in der Amygdala,<br />
im anterioren Cingulum, im Nucleus accumbens und im Hippocampus<br />
der Hypothese entsprechend auf speziell mit S-Nikotin in Verbindung stehende<br />
Konditionierungsprozesse zurückzuführen sein.<br />
Unterschiede in der Wahrnehmung von S-Nikotin zwischen Rauchern und<br />
Rauchern im Entzug<br />
Um mögliche Cravingzentren im Gehirn lokalisieren zu können, wurde ein<br />
Vergleich zwischen den beiden Untersuchungsgruppen Raucher und Raucher<br />
im Entzug für die Reizklasse S-Nikotin durchgeführt, da sich diese<br />
beiden Gruppen per definitionem lediglich durch die Entzugsbedingung<br />
voneinander unterschieden. Dazu wurde auch an dieser Stelle ein Kontrast<br />
eingesetzt, der den direkten Vergleich der beiden Stichproben über die<br />
Hirnregionen hinweg ermöglichte. Im ersten Schritt wurden dafür alle zwischen<br />
den beiden Untersuchungsbedingungen bei S-Nikotin aufgetretenen<br />
Unterschiede identifiziert. Darauf folgend wurde untersucht, ob die beobachteten<br />
Differenzen für alle applizierten trigeminalen bzw. olfaktorischen
Die Untersuchung<br />
Reizklassen, nur bei den beiden Nikotinenantiomeren oder ausschließlich<br />
für S-Nikotin auftraten.<br />
In der olfaktorischen Konzentration zeigten sich dabei für alle Reizklassen<br />
(S.-Nikotin, R-Nikotin, Rose) signifikante Unterschiede. Effekte mit einer<br />
stärkeren Aktivierung bei Rauchern im Entzug fanden sich bilateral im<br />
anterioren Cingulum, im Nucleus Caudatus, im Cerebellum, im lingualen<br />
Gyrus, im Lobulus paracentralis, im medialen frontalen Gyrus, im Putamen<br />
und im Thalamus. Linkshemisphärisch trat bei Rauchern im Entzug ein<br />
stärkeres positives BOLD-Signal im Cingulum, im inferioren frontalen<br />
Gyrus, im Lobulus parietalis inferior, im Lobulus parietalis superior, im<br />
mittleren temporalen Gyrus, im Precuneus und im supramarginalen Gyrus<br />
auf. Rechtshemisphärisch waren entsprechende Reaktionen im fusiformen<br />
Gyrus, im inferioren temporalen Gyrus, im mittleren frontalen Gyrus, im<br />
mittleren okzipitalen Gyrus, im postzentralen Gyrus und im präzentralen<br />
Gyrus zu beobachten. Die hoch dosierten bzw. trigeminalen Substanzen<br />
lösten im Vergleich von Rauchern und Rauchern im Entzug keine signifikanten<br />
Unterschiede aus, die sowohl für CO2 als auch für die beiden Nikotinenantiomere<br />
auftraten.<br />
Wie bereits erwähnt, wurden im nächsten Schritt Effekte untersucht, die<br />
nikotinspezifisch ausgelöst wurden, also nur für die beiden Nikotinenantiomere<br />
auftraten. Auch hier konnten in den niedrigen bzw. olfaktorischen<br />
Konzentrationen signifikant stärkere Aktivierungen bei den Rauchern im<br />
Entzug beobachtet werden. Diese betrafen bilateral das Claustrum, den<br />
Hippocampus, die Insula, den Nucleus accumbens und den parahippocampalen<br />
Gyrus, linkshemisphärisch den fusiformen Gyrus, den Hirnstamm,<br />
den inferioren okzipitalen Gyrus, den inferioren temporalen Gyrus, den<br />
mittleren frontalen Gyrus, den postzentralen Gyrus, den präzentralen Gyrus,<br />
den superioren frontalen Gyrus und den superioren temporalen Gyrus, sowie<br />
rechtshemisphärisch die Amygdala, den inferioren frontalen Gyrus, den<br />
Lobulus parietalis inferior, den Lobulus parietalis superior und den mittleren<br />
temporalen Gyrus. Im hochkonzentrierten bzw. trigeminalen Bereich<br />
trat dieser Effekt lediglich im linken mittleren frontalen Gyrus auf. In Anbetracht<br />
der Ergebnisse des vorherigen Kapitels kann von einem Generali-<br />
167
168<br />
Die Untersuchung<br />
sierungsprozess der erworbenen Konditionierungen für S-Nikotin auf R-<br />
Nikotin ausgegangen werden, so dass die identifizierten nikotinspezifischen<br />
Aktivierungen als mögliche Korrelate des Cravings gewertet werden können.<br />
Im Folgenden werden deshalb die unter den beiden Nikotinenantiomeren<br />
bei Rauchern im Entzug stärker aktivierten Hirnareale mit den subjektiven<br />
Ratings für alle Substanzklassen korreliert, um weitere Anhaltspunkte für<br />
mögliche Cravingzentren zu erhalten. Die Pearson-Korrelation wurde dabei<br />
für die linke Insula (n = 45, r = -0,364, p = 0,014), die rechte Insula (n = 45,<br />
r = -0,303, p = 0,043), den linken inferioren temporalen Gyrus (n = 45, r = -<br />
0,350, p = 0,018), den linken mittleren frontalen Gyrus (n = 45, r = 0,494, p<br />
= 0,001) und den rechten inferioren frontalen Gyrus (n = 45, r = -0,317, p =<br />
0,034) signifikant. Ein Trend kristallisierte sich für den rechten Nucleus<br />
accumbens (n = 45, r = 0,273, p = 0,070) heraus.<br />
Aufgrund der Vorergebnisse aus dem EEG-Teil, dass Raucher und Raucher<br />
im Entzug unter Rose subjektiv das stärkste Craving empfanden, auch die<br />
unter dieser Substanz aufgetretenen Aktivierungen als Korrelate des Rauchverlangens<br />
gewertet werden könnten, wurden auch für die unter allen drei<br />
Substanzen signifikant reagierenden Areale mit den subjektiven Ratings<br />
korreliert. Dabei kristallisierten sich mit Hilfe der Pearson-Korrelation über<br />
die Hedonikeinschätzungen aller drei Substanzklassen signifikante Zusammenhänge<br />
mit dem linken Cingulum (n = 45, r = -0,340, p = 0,022) und im<br />
rechten mittleren frontalen Gyrus (n = 45, r = 0,379, p = 0,10), sowie tendenzielle<br />
Interaktionen mit dem linken Cerebellum (n = 45, r = -0,257, p =<br />
0,089), dem linken Thalamus (n = 45, r = -0,255, p = 0,090) und dem rechten<br />
mittleren okzipitalen Gyrus (n = 45, r = -0,278, p = 0,065) heraus.<br />
Da anhand des vorliegenden Untersuchungsdesigns nicht ausgeschlossen<br />
werden konnte, dass die erfasste Variable Hedonik durch eine weitere Variable,<br />
die den je nach Reizklasse unterschiedlich ausgeprägten trigeminalen<br />
Anteil der Einzelsubstanzen abbildet, beeinflusst wurde, erfolgte zudem<br />
eine Betrachtung der Areale, die zur Schmerzmatrix gezählt werden. Dabei<br />
handelt es sich um die Insula, das anteriore Cingulum, den ventralen orbi-
Die Untersuchung<br />
tofrontalen bzw. inferioren frontalen Kortex, den dorsolateralen präfrontalen<br />
bzw. mittleren frontalen Kortex, den Thalamus und das ventrale Striatum<br />
bzw. den Nucleus accumbens. Da bei der Auswertung der Aktivierungen<br />
die Signifikanzschwellen in den trigeminalen und olfaktorischen Konzentrationen<br />
unterschiedlichen Korrekturen (Bonferroni- bzw. FDR-<br />
Korrektur) unterzogen wurden (s. Kap. 6.8.3.), musste die Analyse der beiden<br />
Bereich getrennt erfolgen. Mit Hilfe einer ordinalen Betrachtung, die<br />
unabhängig von statistischen Signifikanzen erfolgte, zeigte sich in den olfaktorischen<br />
Konzentrationen ein Zusammenhang mit der Stärke der Aktivierung<br />
der Schmerzmatrix in Abhängigkeit von der applizierten Reizklasse<br />
und der Reihenfolge der hedonischen Bewertung der Substanzen. Dabei<br />
reagierte das Gehirn unter Rose in den untersuchten Regionen durchgehend<br />
weniger stark als nach der Gabe der beiden Nikotinenantiomere. Letztere<br />
lagen sowohl in ihrer hedonischen Bewertung als auch in der Stärke der<br />
Aktivierungen in ähnlichen Wertebereichen (s. Kap. 6.8.5.). Auch in den<br />
trigeminalen Substanzklassen konnte dieser Zusammenhang beobachtet<br />
werden. Hier gestaltete sich das Bild jedoch insofern anders, als in vielen<br />
Fällen die beiden Nikotinenantiomere Deaktivierungen hervorriefen, während<br />
der Applikation von CO2 vorwiegend Aktivierungen folgten (s. Anhang<br />
III). Unter Berücksichtigung der negativen Vorzeichen ergab sich<br />
entsprechend der hedonischen Einschätzung (s. Kap. 6.8.5.) die stärkste<br />
positive Reaktion in den untersuchten Hirnregionen für CO2, gefolgt von S-<br />
Nikotin mit einer durchschnittlich betrachtet leicht ausgeprägten Deaktivierung.<br />
Unter R-Nikotin waren die Deaktivierungen tendenziell am stärksten<br />
ausgeprägt.<br />
6.8.5. Ergebnisse der Auswertung der psychophysischen Daten<br />
Analog zu den Berechnungen bei der EEG-Untersuchung wurde auch hier<br />
mit Hilfe von ANOVAs der Einfluss der Reizklasse auf die unterschiedlichen<br />
psychophysischen Ratings zunächst für jede Untersuchungsgruppe<br />
getrennt untersucht. Die Ergebnisse für Raucher und Raucher im Entzug<br />
ergaben erneut signifikante Unterschiede in Abhängigkeit des Geruchs für<br />
die Variablen Hedonik (Raucher: F = 3,306, df = 5, p = 0,008; Raucher im<br />
Entzug: F = 2,785, df = 5, p = 0,020), Intensität Brennen (Raucher: F =<br />
169
170<br />
Die Untersuchung<br />
4,215, df = 5, p = 0,001; Raucher im Entzug: F = 2,358, df = 5, p = 0,044)<br />
und Intensität Stechen (Raucher: F = 12,060, df = 5, p = 0,000; Raucher im<br />
Entzug: F = 6,652, df = 5, p = 0,000). Auch für Nichtraucher ergaben sich<br />
in den gleichen Variablen signifikante Unterschiede (Hedonik: F = 5,418, df<br />
= 5, p = 0,000; Intensität Brennen: F = 4,604, df = 5, p = 0,001; Intensität<br />
Stechen: F = 15,610, df = 5, p = 0,000). Bei allen drei Untersuchungsgruppen<br />
traten im Vergleich der olfaktorischen Sequenz mit der trigeminalen<br />
Reizabfolge hinsichtlich der Ratings Intensität Brennen bzw. Stechen und<br />
Hedonik Signifikanzen auf. Die Rangreihe der hedonischen Einschätzung<br />
der Einzelreize variierte je nach Untersuchungsgruppe diesmal sehr stark.<br />
Die Abfolgen sind beginnend mit der angenehmsten Reizklasse der Tabelle<br />
18 zu entnehmen.<br />
Raucher Raucher im Entzug Nichtraucher<br />
R-Nikotin olfaktorisch<br />
(44,26)<br />
Rose<br />
(43,63)<br />
R-Nikotin trigeminal<br />
(38,22)<br />
S-Nikotin olfaktorisch<br />
(37,51)<br />
S-Nikotin trigeminal<br />
(34,72)<br />
CO2<br />
(26,59)<br />
Rose<br />
(49,12)<br />
R-Nikotin trigeminal<br />
(43,07)<br />
R-Nikotin olfaktorisch<br />
(42,56)<br />
S-Nikotin olfaktorisch<br />
(36,62)<br />
S-Nikotin trigeminal<br />
(33,23)<br />
CO2<br />
(29,25)<br />
Rose<br />
(46,03)<br />
R-Nikotin olfaktorisch<br />
(33,99)<br />
S-Nikotin olfaktorisch<br />
(30,84)<br />
R-Nikotin trigeminal<br />
(28,35)<br />
S-Nikotin trigeminal<br />
(24,67)<br />
CO2<br />
(21,10)<br />
Tabelle 18: Rangfolge der Einzelreize hinsichtlich ihrer hedonischen Bewertung nach Untersuchungsgruppen<br />
getrennt betrachtet (Mittelwerte in Klammern)<br />
Zur Identifikation von Unterschieden zwischen den einzelnen Untersuchungsgruppen<br />
wurden erneut ANOVAs eingesetzt. Zwischen Rauchern<br />
und Nichtrauchern ergaben sich lediglich in den trigeminalen Konzentrationen<br />
signifikante Einflüsse des Rauchstatus auf die Ratings. Die Reize wurden<br />
von den Rauchern signifikant angenehmer eingeschätzt (F = 7,846, df =<br />
1, p = 0,006). Raucher und Raucher im Entzug unterschieden sich aus-
Die Untersuchung<br />
schließlich hinsichtlich des eingeschätzten Cravings. Dabei resultierten<br />
statistische Signifikanzen in der olfaktorischen Konzentration (F = 11,875,<br />
df = 1, p = 0,001). Trigeminal war ein statistischer Trend zu beobachten (F<br />
= 2,799, df = 1, p = 0,098), wobei Raucher im Entzug erwartungsgemäß<br />
höhere Werte für das Rauchverlangen schätzten.<br />
Zur weiteren Differenzierung der erhaltenen Ergebnisse wurden wiederum<br />
explorative t-Tests eingesetzt. Im Vergleich Raucher vs. Nichtraucher zeigten<br />
sich dabei signifikante Unterschiede in der Intensität des Stechens von<br />
trigeminalem S-Nikotin (T = 2,472, df = 28, p = 0,020). Raucher und Raucher<br />
im Entzug unterschieden sich hinsichtlich des Cravings bei olfaktorischem<br />
S-Nikotin (T = -3,13, df = 14, p = 0,007), bei olfaktorischem R-<br />
Nikotin (T = 3,02, df = 14, p = 0,009) und bei Rose (T = -3,21, df = 14, p =<br />
0,006).<br />
6.8.6. Zusammenfassung der Ergebnisse aus der fMRT-<br />
Untersuchung<br />
Im ersten Teil der Auswertung der Daten aus der funktionellen Magnetresonanztomographie<br />
wurde zunächst untersucht, ob die applizierten Reize in<br />
olfaktorischer und trigeminaler Konzentration zu ähnlichen Untersuchungsergebnissen<br />
führten wie von verschiedenen anderen Voruntersuchungen<br />
berichtet (z.B. Boyle et al., 2007; Heinke, 2008; Hummel et al., 2005; Iannilli<br />
et al., 2008). Die Regions of Interest konnten dabei für beide Konzentrationsbereiche<br />
bestätigt werden, jedoch traten auch in niedrigen Konzentrationen<br />
Aktivierungen in Hirnarealen auf, die typischerweise mit trigeminalen<br />
Reizungen in Verbindung gebracht werden. Die Aktivierungsmuster, die<br />
unter den beiden Nikotinsorten zu beobachten waren, deckten sich weitgehend<br />
mit den Ergebnissen von Albrecht (2008). Während in den olfaktorischen<br />
Konzentrationen ausschließlich Aktivierungen resultierten, waren im<br />
trigeminalen Bereich vorwiegend Deaktivierungen festzustellen.<br />
Unterschiede zwischen Nichtrauchern und Rauchern in der Reaktion auf S-<br />
Nikotin zeigten sich in erster Linie in den niedrigen bzw. olfaktorischen<br />
Konzentrationen, was mit den Ergebnissen aus der EEG-Untersuchung in<br />
171
172<br />
Die Untersuchung<br />
Einklang steht. Diese traten vorwiegend in Bereichen auf, die mit Schmerzverarbeitung<br />
(z.B. somatosensorischer Kortex I und II, Cerebellum, Thalamus)<br />
und dem Craving (z.B. Insula, ventrales Striatum, parahippocampaler<br />
Kortex, Hippocampus, präfrontaler Kortex) in Verbindung gebracht werden.<br />
Es wird davon ausgegangen, dass diese beobachteten Unterschiede auf<br />
Habituationsprozesse zurückzuführen sind, die Raucher mit S-Nikotin bereits<br />
sammeln konnten, während Nichtraucher weitgehend naiv darauf reagierten.<br />
Raucher im Entzug scheinen hingegen für trigeminale Aspekte<br />
sensibilisiert zu sein und diese früher wahrzunehmen, während olfaktorische<br />
Aspekte eher in den Hintergrund treten. Dass für die trigeminalen<br />
Reizklassen keine Unterschiede zu beobachten waren, könnte wie bereits<br />
erwähnt auf einen Deckeneffekt zurückzuführen sein. Dafür sprechen auch<br />
Ergebnisse aus früheren Untersuchungen (Hummel, Hummel, Pauli & Kobal,<br />
1992; Thürauf, Kaegler, Renner, Barocka & Kobal, 2000), in denen mit<br />
schwellennahen trigeminalen Reizen gearbeitet wurde und bei denen sich<br />
die Reaktionen von Rauchern und Nichtrauchern unterschieden. In der vorliegenden<br />
Untersuchung wurden mit 8 l/min hingegen sehr hohe Konzentrationen<br />
für die beiden Nikotinstereoisomere gewählt.<br />
Im Vergleich der beiden Nikotinenantiomere reagierten lediglich die Nichtraucher<br />
mit unterschiedlichen Aktivierungsmustern auf die beiden Substanzen.<br />
Bei Rauchern und bei Rauchern im Entzug schienen die diskriminativen<br />
Eigenschaften weniger ausgeprägt wahrgenommen zu werden. Dieser<br />
Effekt könnte durch den Lernprozess der Generalisierung zu erklären sein,<br />
so dass die bereits mit S-Nikotin stattgefundenen Konditionierungsprozesse<br />
auf R-Nikotin übertragen wurden. Der Hypothese entsprechend zeigten sich<br />
jedoch in typischerweise mit Craving verbundenen Regionen (z.B. Amygdala,<br />
anteriores Cingulum, Nucleus accumbens, Hippocampus) signifikante<br />
Unterschiede zwischen den beiden Enantiomeren, die als für S-Nikotin<br />
spezifische Konditionierungsprozesse gewertet werden können.<br />
Auch der Vergleich der Reaktionen auf S-Nikotin von Rauchern und Rauchern<br />
im Entzug deutete auf eine erhöhte trigeminale Sensibilität bei Rauchern<br />
im Entzug hin, da wiederum vor allem Schmerz verarbeitende Hirnareale<br />
signifikant unterschiedlich reagierten. Unterschiedliche Reaktionen
Die Untersuchung<br />
im Gehirn, die spezifisch für S-Nikotin zu beobachten gewesen wären,<br />
traten nicht auf. Jedoch konnten eine Reihe von nikotinspezifischen Differenzen<br />
zwischen den beiden Untersuchungsgruppen festgestellt werden, die<br />
auf den Entzug zurückzuführen sein könnten. Aufgrund der bereits oben<br />
geschilderten Generalisierungsprozesse hätten damit beide Nikotinenantiomere<br />
gleichermaßen die Fähigkeit, in den dargestellten Arealen das Verlangen<br />
zu Rauchen auszulösen. Auf biologischer Ebene kann dieses Phänomen<br />
durch die Stickstoffatome der beiden Stereoisomere, die fast identisch sind,<br />
erklärt werden (Aceto, Tucker, Ferguson & Hinson, 1986). Im Gegensatz zu<br />
Opioidenantiomeren, die sich in ihrer Affinität für mu1-Rezeptoren um das<br />
Zehnfache voneinander unterscheiden (Kristensen, Christensen & Christrup,<br />
1995), sind aufgrund der einfachen Struktur des Nikotinmoleküls nur geringe<br />
stereoselektive Unterschiede zu erwarten. Um aber wirklich nur die Regions<br />
of Interests für das Craving zu identifizieren, wurden die Daten der<br />
gefundenen Voxel mit den zugehörigen Psychophysikdaten korreliert. Dabei<br />
kristallisierten sich bilateral der präfrontale Kortex und die Insula und<br />
linkshemisphärisch der inferiore temporale Gyrus und das Cingulum für das<br />
Verlangen zu Rauchen als relevant heraus. Der Nucleus accumbens, das<br />
linke Cerebellum, der linke Thalamus und rechte mittlere okzipitale Gyrus<br />
wiesen ebenfalls tendenziell einen Zusammenhang mit dem empfundenen<br />
Craving auf.<br />
In Bezug auf die psychophysischen Daten bestätigte sich der Trend, dass<br />
Nichtraucher die Reizklassen negativer bewerteten als die beiden anderen<br />
Untersuchungsgruppen. Andere beobachtete Unterschiede, z.B. in der Intensität<br />
des Brennens oder der Ausprägung des Cravings, können im Wesentlichen<br />
auf die Untersuchungsbedingungen oder die Reizklassen zurückgeführt<br />
werden und finden deswegen an dieser Stelle keine Erwähnung<br />
mehr.<br />
173
Integration und Diskussion der Daten<br />
7. Integration und Diskussion der Daten<br />
Das Ziel dieser Arbeit war es zum Einen, mit Hilfe von evozierten Potentialen<br />
im EEG Unterschiede in den Amplituden p1, n1 und p2 zwischen Nichtrauchern,<br />
Rauchern und Rauchern im Entzug zu untersuchen, die auf Konditionierungsprozesse<br />
und damit in Zusammenhang stehende veränderte<br />
hedonische Bewertungen bei den letztgenannten beiden Gruppen zurückzuführen<br />
sein könnten. Weiterhin sollten die im ersten Teil der Arbeit gefundenen<br />
Differenzen mit Hilfe eines ereigniskorrelierten Designs im fMRT<br />
bezüglich der Lokalisation interessanter Zentren des Cravings und von<br />
Konditonierungsprozessen weiter ausdifferenziert werden.<br />
7.1. Stimulation mit unterschiedlichen Reizklassen<br />
Soweit der Autorin bekannt ist, wurden in bisherigen Untersuchungen entweder<br />
ausschließlich S-Nikotinstimuli (z.B. Albrecht, 2008) oder exklusive<br />
andere Substanzen wie beispielsweise Vanillin oder Schwefelwasserstoff<br />
(z.B. Savic et al., 2002; Livermore et al., 1992; Boyle et al, 2007; Hummel<br />
et al., 2005) für die Untersuchung neuronaler Aktivitäten verwendet. Da ein<br />
Hauptfokus dieser Studie auf der Identifizierung von Konditionierungsprozessen<br />
durch die dauerhafte Konfrontation mit natürlichem, in Tabakrauch<br />
vorkommendem S-Nikotin bei Rauchern und Rauchern im Entzug lag, wurden<br />
Kontrollreize benötigt, um nikotinunabhängige Veränderungen getrennt<br />
von Sensibilisierungspozessen erfassen zu können. Dafür erschienen ein als<br />
rein olfaktorischer Phenylethylalkohol und ein als rein trigeminal bekannter<br />
Reiz CO2 besonders geeignet. Zudem war es so möglich zu untersuchen,<br />
welche zusätzlichen Effekte unter Nikotin im Vergleich zu den beiden Kontrollreizen<br />
zu beobachten sind.<br />
Zudem wurde neben dem natürlichen S-Enantiomer das künstlich hergestellte<br />
R-Nikotin eingesetzt. Auf diese Weise konnten zwei Substanzen mit<br />
identischen physikochemischen Eigenschaften verglichen werden. Da Raucher<br />
im Gegensatz zum künstlichen Isomer durch den Zigarettenkonsum<br />
bereits Vorerfahrungen mit dem natürlichen Enantiomer sammeln konnten,<br />
175
176<br />
Integration und Diskussion der Daten<br />
wurde davon ausgegangen, dass auftretende Differenzen in der Wahrnehmung<br />
der Substanzen auf Lernprozesse zurückzuführen sind.<br />
In der vorliegenden Studie wurden sowohl die olfaktorischen als auch die<br />
trigeminalen Aspekte von Nikotin untersucht, wobei im Kontrast zu bisherigen<br />
Studien mit 8 l/min sehr hohe Konzentrationen verwendet wurden.<br />
Dies geschah aus zwei Gründen: Zum Einen hatten verschiedene Voruntersuchungen<br />
bereits von Unterschieden in der hedonischen Bewertung zwischen<br />
Rauchern und Nichtrauchern in mittleren trigeminalen Konzentrationen<br />
(Hummel et al., 1992; Thürauf et al., 2000) berichtet, zum Anderen ist<br />
aber auch die hohe Rückfallquote bei Rauchern durch den Zigarettengeruch<br />
bekannt. Da sich sowohl in der EEG-, als auch in der fMRT-Untersuchung<br />
nur geringe Unterschiede in den trigeminalen Konzentrationen zwischen<br />
den Untersuchungsgruppen zeigten, muss bei einer Konzentration von 8<br />
Litern pro Minute möglicherweise von einem Deckeneffekt ausgegangen<br />
werden, der bei allen Teilnehmern zu als ähnlich unangenehm empfundenen<br />
Reaktionen geführt haben könnte.<br />
7.2. EEG-Untersuchung<br />
Identifikation der Amplitudenmaxima<br />
Im ersten Teil der Untersuchung wurden zunächst die Amplitudenmaxima<br />
der einzelnen Reizklassen in den olfaktorischen und trigeminalen Konzentrationen<br />
bestimmt. Übereinstimmend mit Kobal & Hummel (1988, 1991,<br />
1994) und Livermore et al. (1992) lag das olfaktorische Maximum für Rose<br />
und S-Nikotin bei Pz. Auch für R-Nikotin war der Ausschlag für die meisten<br />
Amplituden an dieser Ableiteposition am größten, jedoch ergab sich eine<br />
leichte Verschiebung zu zentralen Regionen für n1 und p1n1. Da sich in der<br />
fMRT-Untersuchung in der Gruppe der Raucher im Entzug eine Sensibilisierung<br />
für trigeminale Aspekte herauskristallisiert hatte, könnten die Frontalisierungstendenz<br />
als weiterer Hinweis für eine sensiblere Wahrnehmung<br />
von Schmerzaspekten gedeutet werden. Um diese Hypothese näher untersuchen<br />
zu können, wäre jedoch eine getrennte Auswertung der Amplitudenmaxima<br />
für die einzelnen Untersuchungsgruppen erforderlich, wobei der
Integration und Diskussion der Daten<br />
Maximalausschlag für Nichtraucher bei Pz liegen müsste. Zudem würde<br />
dieses Ergebnis bedeuten, dass R-Nikotin stärkere trigeminale Eigenschaften<br />
besitzt als bisher angenommen. Diese würden sich dann im Gehirn bereits<br />
in sehr niedrigen Konzentrationen sehr früh zeigen, scheinen aber die<br />
Schwelle der bewussten Wahrnehmung viel später zu überschreiten als bei<br />
S-Nikotin. Die erwartete Frontalisierung in Richtung der Elektrode Cz für<br />
trigeminale Reize konnte ebenfalls bestätigt werden. Auch hier lag das<br />
Zentrum eher im parietalen Bereich, es zeigte sich aber eine Verschiebung<br />
zu zentralen Regionen für R-Nikotin und CO2. Für S-Nikotin änderte sich<br />
das Verteilungsmuster nicht, jedoch wurden die Amplituden unter Pz tendenziell<br />
kleiner, während sie unter Cz eher zunahmen. Dies deutet erneut<br />
auf Habituationseffekte der Raucher bezüglich der trigeminalen Aspekte in<br />
der Nikotinwahrnehmung hin. Betrachtet man in diesem Kontext zudem die<br />
Ergebnisse der fMRT-Untersuchung, kann festgestellt werden, dass in zentralen<br />
und frontalen Regionen und unter trigeminaler Reizung vorwiegend<br />
eine Deaktivierung der Hirnregionen zu beobachten war. Diese korreliert<br />
nach Lasogga (2007), Li, Luo, Schulte und Hudetz (2006), Wade (2002)<br />
und Czisch, Wehrle, Kaufmann, Wetter, Holsboer, Pollmächer, sowie Auer<br />
(2004) mit einer Abnahme der reizinduzierten neuronalen Antwort und<br />
einer Zunahme der generellen oszillatorischen Aktivität des EEGs. Diese<br />
führt Lasogga (2007) auf die Unterdrückung eines erlernten motorischen<br />
Verhaltensprogramms, also auf die Aktivierung GABAerger Rezeptoren,<br />
zurück. Da sich in der fMRT-Untersuchung im parietalen Bereich vorwiegend<br />
positive BOLD-Signale zeigten, stehen die Ergebnisse der EEG-<br />
Untersuchung mit diesen Resultaten in Einklang. Durch die Tatsache, dass<br />
in diese Auswertung alle Probanden eingeschlossen wurden und somit 30<br />
Teilnehmer (Raucher, Raucher im Entzug) über eine Vorgeschichte mit<br />
Nikotin verfügten, könnten sich in den Ergebnissen komplexere Mechanismen<br />
wie z.B. mit dem Rauchen assoziierte Handlungsabläufe widerspiegeln.<br />
So könnte z.B. das zum Mund Führen der Zigarette, das Anzünden<br />
oder eine spezielle Handhaltung, die von Rauchern und Rauchern im Entzug<br />
mit dem Nikotingeruch assoziativ verknüpft sind, als Verhaltensprogramme<br />
unterdrückt worden sein. Bei einer getrennten Untersuchung der<br />
Nichtraucher dürfte es dann lediglich zu einer Geruchswahrnehmung und<br />
einem entsprechenden Aktivierungsmuster kommen.<br />
177
178<br />
Integration und Diskussion der Daten<br />
Auswertung der Amplituden und Latenzzeiten<br />
Im nächsten Schritt wurden Unterschiede zwischen Rauchern und Nichtrauchern<br />
bzw. Rauchern und Rauchern im Entzug sowohl mit Hilfe von ANO-<br />
VAs als auch mit explorativen t-Tests untersucht. Als einzige nicht signifikante<br />
Variable in diesem Vergleich kristallisierte sich die Amplitude p1 in<br />
der trigeminalen Konzentration heraus, was die Annahme eines Deckeneffektes<br />
weiter unterstützt. Zudem wurde bereits erwähnt, dass die Amplitude<br />
p1 generell sehr gering ausgeprägt ist und deshalb ein schlechtes Signal-<br />
Rausch-Verhältnis aufweist. In allen anderen Komponenten der evozierten<br />
Potentiale zeigten sich signifikant größere p2-Amplituden für Nichtraucher,<br />
was nach Kobal et al. (1992) und Becker et al. (1993) für eine negativere<br />
Bewertung der Reizklassen spricht. Dies deckt sich mit den Ergebnissen der<br />
psychophysischen Auswertung. In der Auswertung Raucher vs. Raucher im<br />
Entzug zeigten sich signifikante Differenzen erneut nur im olfaktorischen<br />
Konzentrationsbereich. Hier wiesen Raucher im Entzug durchgehend die<br />
größeren Amplituden auf. Dies könnte einerseits bedeuten, dass die dreitägige<br />
Abstinenz eine bessere Riechfähigkeit nach sich zieht und die Bewertung<br />
auf diesem Wege beeinflusst wird. Andererseits könnten diese Effekte<br />
jedoch auch durch stärkeres Craving ausgelöst worden sein und die damit<br />
verbundenen Emotionen könnten eine negativere hedonische Einschätzung<br />
nach sich gezogen haben. Für die zweite Annahme sprechen auch die in den<br />
späten Komponenten signifikant verkürzten Latenzzeiten der Raucher im<br />
Entzug im Vergleich zur normalen Rauchergruppe, jedoch wiederum nur im<br />
olfaktorischen Bereich, der für alle olfaktorischen Reizklassen getrennt zu<br />
beobachten war. Würde eine im Vergleich zu Rauchern sensibilisierte<br />
Wahrnehmung vorliegen, sollte sich diese eher in verkürzten Latenzzeiten<br />
in den frühen Komponenten widerspiegeln. Eine Verkürzung der Latenzzeiten<br />
in den späten Anteilen des evozierten Potentials würde dagegen für eine<br />
veränderte kortikale Prozessierung sprechen. Im direkten graphischen Vergleich<br />
zeigte sich außerdem, dass die Latenzzeiten der späten EEG-Anteile<br />
bei Rauchern im Entzug sogar gegenüber den Nichtrauchern deutlich verkürzt<br />
war, sie also eine schnellere Prozessierung zeigten als die Nichtraucher,<br />
die die Reize am negativsten beurteilten. Zudem konnten mit Hilfe<br />
einer Regressionsanalyse signifikante Zusammenhänge zwischen dem Craving<br />
und den Latenzzeiten festgestellt werden, die bereits von Domino
Integration und Diskussion der Daten<br />
(2003) postuliert wurden. Jedoch waren sie in der vorliegenden Untersuchung<br />
im Gegensatz zu seinem Ergebnis verkürzt. Betrachtet man die geschilderten<br />
Ergebnisse im Zusammenspiel, spricht dies eher für die Annahme<br />
eines durch Craving ausgelösten Effekts.<br />
Auswertung von Frontalisierungs – und Lateralisierungstendenzen<br />
Die untersuchten Lateralisierungstendenzen erwiesen sich lediglich für die<br />
frühen Komponenten bei der Gruppe der Raucher als signifikant, für Raucher<br />
im Entzug ergab sich speziell für S-Nikotin eine Verschiebung des<br />
Reaktionsschwerpunkts in die rechte Hirnhälfte. Weitere Untersuchungen<br />
könnten klären, ob bei Rauchern möglicherweise ein Zusammenhang mit<br />
der Händigkeit besteht. Hinsichtlich der Frontalisierungstendenzen resultierte<br />
ausschließlich bei den Entzügigen ein signifikantes Ergebnis. Dabei<br />
trat dieser Effekt in den olfaktorischen Konzentrationen vorwiegend in den<br />
frühen Komponenten auf, was wiederum die Annahme einer sensibleren<br />
Wahrnehmung unterstützen würde. Hingegen zeigte sich in späten Komponenten<br />
eher eine Verschiebung in zentraler Richtung. Die trigeminalen<br />
Anteile scheinen entsprechend stärker in Bewertungsprozesse mit einzufließen,<br />
was mit der negativeren hedonischen Einschätzung in Einklang steht.<br />
Die beobachteten Frontalisierungstendenzen sind zudem kongruent zu den<br />
beschriebenen olfaktorischen und trigeminalen Amplitudenmaxima.<br />
Auswertung der psychophysischen Daten<br />
Erwartungsgemäß lagen die Schwellen für die beiden Nikotinsorten bei<br />
allen Untersuchungsgruppen im olfaktorischen Bereich nahe beieinander,<br />
während die bewusste trigeminale Wahrnehmung bei S-Nikotin deutlich<br />
niedriger lag als bei R-Nikotin (Thürauf, Kaegler, Dietz, Barocka & Kobal,<br />
1999). Die Bedeutung trigeminaler Aspekte für die negativere Gesamtbewertung<br />
der Reize in Verbindung mit den geringer ausgeprägten P2-<br />
Amplituden steht im Einklang mit den subjektiven Bewertungen der Nichtraucher.<br />
Die beobachtete Tendenz einer sensibleren Schmerzwahrnehmung<br />
bei Rauchern im Entzug, die sich auch in den EEG-Daten zeigte, fand jedoch<br />
nur eine bedingte Entsprechung in den visuellen Ratings. Hier lagen<br />
die trigeminalen Schwellen für R-Nikotin nach drei Tagen Abstinenz in<br />
179
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Integration und Diskussion der Daten<br />
einem ähnlichen Konzentrationsbereich wie unter normalen Rauchbedingungen.<br />
Für S-Nikotin hingegen spiegelte sich im Vergleich zur Rauchergruppe<br />
für die Teilnehmer im Entzug eine deutliche Sensibilisierung wider.<br />
Dieses Ergebnis könnte darauf zurückzuführen sein, dass R-Nikotin im<br />
Vergleich zu S-Nikotin deutlich geringer ausgeprägte trigeminale Eigenschaften<br />
besitzt, die zwar vorbewusst vom Gehirn verarbeitet, aber nicht<br />
bewusst vom Probanden wahrgenommen werden.<br />
Ein zusätzliches überraschendes Ergebnis zeigte sich bei der Betrachtung<br />
der Zusammenhänge zwischen subjektiv empfundenem Craving und der<br />
eingeschätzten Hedonik bei Rauchern und Rauchern im Entzug. Je angenehmer<br />
der Reiz beurteilt wurde, desto stärker war das Verlangen zu Rauchen<br />
ausgeprägt. Wie in früheren Untersuchungen postuliert (Evans, Cui &<br />
Starr, 1995; Knott, 1991), spiegelte sich die Bewertung auch in der späten<br />
Komponente p2 invers wider, während die Intensitätsratings mit frühen<br />
Komponenten signifikant korrelierten. Dies lässt auf eine Kodierung endogener<br />
Prozesse wie Bedeutung und Bewertung in der späten Komponente<br />
und physikalischer Reizeigenschaften in den frühen EEG-Anteilen schließen.<br />
Die anders gearteten Einschätzungen der Intensität des Stechens, die<br />
eher mit späten Komponenten korrelierten, lassen möglicherweise auf kognitive<br />
Prozesse schließen, die an der Unterscheidung zwischen Brennen und<br />
Stechen beteiligt sind.<br />
7.3. fMRT-Untersuchung<br />
Aktivierungen nach Applikation olfaktorischer bzw. niedrig dosierter Reize<br />
Auch im zweiten Teil der Studie wurden zunächst die resultierenden Aktivierungsmuster<br />
mit denen aus bekannten Voruntersuchungen verglichen. In<br />
Übereinstimmung mit Boyle et al. (2007), Heinke (2008), Hummel et al.<br />
(2005) und Iannilli, del Gratta, Gerber, Romani und Hummel (2008) traten<br />
Aktivierungen bilateral in der Amygdala, im orbitofrontalen Kortex und in<br />
der Insula auf. Diese Regionen werden dem olfaktorischen System zugeordnet.<br />
Im piriformen Kortex hingegen konnte für Rose kein BOLD-Signal<br />
detektiert werden. Die Reaktionsmuster unter S- und R-Nikotin fielen im<br />
Wesentlichen identisch aus, jedoch fanden sich hier Aktivierungen im lin-
Integration und Diskussion der Daten<br />
ken piriformen Kortex. Bisherige Untersuchungen (Levy et al., 1997; Zatorre<br />
et al., 1992) gingen davon aus, dass der piriforme Kortex während des<br />
Riechvorgangs aktiviert ist. Das vorliegende Ergebnis steht im Einklang mit<br />
den Ergebnissen von Boyle et al. (2007) und Heinke et al. (2008), die ebenfalls<br />
mit rein olfaktorischen Substanzen arbeiteten. Sie sprechen dafür, dass<br />
der piriforme Kortex an der Verarbeitung von Reizen mit einer Mischung<br />
aus olfaktorischen und trigeminalen Eigenschaften beteiligt ist, jedoch nicht<br />
oder deutlich weniger stark bei rein olfaktorischen oder trigeminalen Substanzen.<br />
Zusätzlich traten Aktivierungen im superioren temporalen Gyrus<br />
auf, der mit der frühen kognitiven Verarbeitung olfaktorischer Reize in<br />
Verbindung gebracht wird (Kettenmann et al., 1996), im Nucleus caudatus,<br />
dem eine Funktion in der olfaktorischen Diskrimination zugeschrieben wird<br />
(Savic et al., 2000), und dem Cerebellum, das ebenfalls in die Verarbeitung<br />
von Gerüchen involviert sein soll (Boyle et al., 2007). Zudem zeigten sich<br />
BOLD-Signale im Okzipitallappen (lingualer Gyrus, Cuneus), in dem der<br />
visuelle Kortex verortet wird, im supramarginalen Gyrus, der mit semantischer<br />
Repräsentation in Zusammenhang gebracht wird (Russ, Mack, Grama,<br />
Lanfermann & Knopf, 2003) und im mittleren temporalen Gyrus, dem eine<br />
Rolle für die Distanzeinschätzung zugeschrieben wird (Martin, Wiggs,<br />
Ungerleider & Haxby, 1996). Da auch Korrelationen mit dem subjektiv<br />
empfundenen Craving festgestellt wurden, kann eine Artefaktbildung aufgrund<br />
des Untersuchungsaufbaus mit der visuellen Analogskala ausgeschlossen<br />
werden. Dem anterioren Cingulum wird eine spezifische Rolle für<br />
das Craving zugeschrieben (Brody et al., 2004). Da die Aktivierungsmuster<br />
über alle drei Untersuchungsgruppen hinweg summiert wurden und somit<br />
die Gruppe der Raucher erneut überwog, erscheint eine Beteiligung dieser<br />
Region an der Verarbeitung der dargebotenen Reize nach dem Ergebnis der<br />
EEG-Untersuchung, dass angenehme Reize das Craving steigern, nachvollziehbar.<br />
Es fanden sich jedoch auch Areale, die in erster Linie mit der<br />
Schmerzverarbeitung assoziiert sind. Dazu gehören der somatosensorische<br />
Kortex I und II (postzentraler Gyrus, Lobulus parietalis inferior, präzentraler<br />
Gyrus), der superiore frontale Gyrus (Heinke, 2008) und der Thalamus.<br />
Dieses Muster war für die beiden Nikotinsorten zu erwarten, da sie eine<br />
trigeminale Komponente besitzen. Für den Geruchsstoff Phenylethylalkohol,<br />
der als rein olfaktorische Substanz gilt, ist dies jedoch überraschend.<br />
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Integration und Diskussion der Daten<br />
Dies könnte der Effekt eines Artefakts gewesen sein (z.B. unbeabsichtigte<br />
Vermischung von Substanzen durch das Olfaktometer). Es wäre jedoch<br />
auch denkbar, dass bei Rose eine Nozizeption ohne bewusste Schmerzwahrnehmung<br />
ausgelöst worden ist. Die geschilderten Aktivierungsmuster<br />
decken sich im Wesentlichen mit den Ergebnissen von Albrecht (2008).<br />
Statt einer Aktivierung im Lobulus parietalis inferior fand diese Arbeitsgruppe<br />
jedoch eine Beteiligung des Lobulus parietalis superior und des<br />
Precuneus. Diese Regionen liegen sehr nahe beieinander, so dass der Unterschied<br />
möglicherweise auf die unterschiedlichen Auswertungsprogramme<br />
oder Unschärfen in der Auswertung zurückgeführt werden können. In der<br />
vorliegenden Untersuchung wurden hingegen vor dem oben geschilderten<br />
Hintergrund zusätzlich BOLD-Signale im Nucleus caudatus, im anterioren<br />
Cingulum, im lingualen Gyrus und im Cuneus detektiert.<br />
Aktivierungen nach Applikation trigeminaler bzw. hoch dosierter Reize<br />
Ebenfalls in Übereinstimmung mit Boyle et al. (2007), Heinke (2008),<br />
Hummel et al. (2005) und Iannilli et al. (2008) konnten für den rein trigeminalen<br />
Reiz CO2 im rechten Cerebellum, in der linken Insula, im rechten<br />
orbitofrontalen Gyrus, bilateral im piriformen Kortex, bilateral im postzentralen<br />
Gyrus und im linken Thalamus Aktivierungen detektiert werden. Eine<br />
Deaktivierung zeigte sich in der rechten Insula. Auch hier fand sich im<br />
anterioren Cingulum ein zusätzliches Areal, das mit einer Deaktivierung auf<br />
die Applikation von CO2 reagierte. Wie bereits beschrieben werden sowohl<br />
der Insula als auch dem anterioren Cingulum eine Beteiligung an Cravingprozessen<br />
zugeschrieben. Der in der EEG-Untersuchung aufgetretene<br />
Zusammenhang zwischen Craving und Hedonik konnte in der fMRT-<br />
Untersuchung erneut bestätigt werden, so dass die Deaktivierungen in den<br />
beiden beschriebenen Regionen als negatives Korrelat des Rauchverlangens<br />
interpretiert werden könnten. Anders als im olfaktorischen Bereich unterschied<br />
sich das trigeminale Aktivierungsmuster unter Nikotin von dem des<br />
Kontrollreizes. Statt einer Aktivierung im rechten Cerebellum zeigte sich<br />
eine Deaktivierung im linken Cerebellum. Zudem konnten bilaterale Deaktivierungen<br />
im präzentralen Gyrus gefunden werden, eine Antwort des linken<br />
Thalamus war wiederum nicht zu beobachten. Stattdessen trat eine<br />
Deaktivierung im rechten Thalamus auf. In der linken Insula trat kein Signal
Integration und Diskussion der Daten<br />
auf, hingegen reagierte der linke orbitofrontale Gyrus statt mit einer Aktivierung<br />
mit einer Deaktivierung. Die genannten Areale sind alle an der<br />
Steuerung motorischer Funktionen beteiligt, so dass die negativen BOLD-<br />
Signale durch den größeren Anteil der Raucher- bzw. Entzugsgruppe (n =<br />
30, Nichtraucher: n = 15) in der Auswertung wiederum auf eine Unterdrückung<br />
eines gelernten Verhaltens schließen lassen (Czischet al., 2004; Lasogga,<br />
2007; Li et al., 2006; Wade, 2002). Im rechten orbitofrontalen Gyrus<br />
zeigte sich eine Aktivierung unter S-Nikotin, nicht jedoch nach der Applikation<br />
des anderen Enantiomers. Diese Region kristallisierte sich auch in<br />
der vorliegenden Untersuchung als biologisches Korrelat des Cravings heraus,<br />
was die spezifische Aktivierung unter S-Nikotin erklärt. Im piriformen<br />
Kortex konnte unter beiden Isomeren kein Signal detektiert werden. Dadurch<br />
wird die Annahme eines Deckeneffekts durch die hohen Konzentrationen<br />
unterstützt, die eine Unterdrückung der olfaktorischen Aspekte nach<br />
sich zieht (Green & Lawless, 1991; Kobal & Hummel, 1988; Livermore,<br />
Hummel & Kobal, 1992) und entsprechend durch die „fehlende Mischung“<br />
beider Aspekte keine Aktivierung des piriformen Kortex erfolgte. Die gefundenen<br />
Aktivierungsmuster decken sich ebenfalls im Wesentlichen mit<br />
den bereits von Albrecht (2008) berichteten. Wiederum zeigte sich in dieser<br />
Studie zusätzlich eine Deaktivierung im anterioren Cingulum. Im Gegensatz<br />
zu Albrecht (2008) waren die meisten BOLD-Signale in dieser Untersuchung<br />
jedoch negativ. Dies könnte darauf zurückzuführen sein, dass die<br />
vorliegende Studie mit Extremgruppen durchgeführt wurde. Albrecht<br />
(2008) arbeitete mit Gelegenheitsrauchern, bei denen die zum Rauchen<br />
zugehörigen Verhaltensmuster noch nicht oder nicht so ausgeprägt und<br />
habitualisiert sind, dass die Verhaltensprogramme bei suchtrelevanter<br />
Reizkonfrontation unterdrückt werden müssten. Die Ergebnisse widersprechen<br />
sich also nicht, sondern ergänzen sich eher durch die Rekrutierung<br />
unterschiedlicher Probandengruppen. Die genannte Arbeitsgruppe fand<br />
zudem Aktivierungen im Nucleus caudatus und im mittleren, sowie superioren<br />
temporalen Gyrus. Da diesen wie bereits erwähnt eine Funktion in der<br />
olfaktorischen Diskrimination (Savic et al., 2000) bzw. in der frühen kognitiven<br />
Verarbeitung olfaktorischer Reize (Kettenmann et al., 1996) zugeschrieben<br />
wird, spricht das Nichtauftreten von Aktivierungen in den genannten<br />
Hirnregionen in der vorliegenden Studie erneut für einen trigemina-<br />
183
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Integration und Diskussion der Daten<br />
len Deckeneffekt. Für eine nähere Untersuchung der aufgestellten Hypothesen<br />
wäre eine getrennte Betrachtung der Aktivierungsmuster für die drei<br />
Probandengruppen erforderlich. Dies ist jedoch nicht Ziel dieser Arbeit<br />
gewesen und würde den Rahmen sprengen.<br />
Unterschiede in der Wahrnehmung von S-Nikotin bei Rauchern und Nichtrauchern<br />
Im direkten Vergleich hinsichtlich ihrer Reaktionen auf S-Nikotin ergaben<br />
sich nach Subtraktion der Werte der Nichtraucher von denen der Raucher<br />
durchgehend positive t-Werte. Dies bedeutet, dass bei fehlender Vorerfahrung<br />
mit dieser Substanz bilateral stärkere Aktivierungen in der Amygdala,<br />
im anterioren Cingulum, im Cerebellum, im Claustrum, im fusiformen<br />
Gyrus, im Hirnstamm, im inferioren frontalen Gyrus, im inferioren temporalen<br />
Gyrus, in der Insula, im Lobulus paracentralis, im Lobulus parietalis<br />
inferior, im medialen frontalen Gyrus, im mittleren frontalen Gyrus, im<br />
mittleren okzipitalen Gyrus, im mittleren temporalen Gyrus, im Nucleus<br />
accumbens, im parahippocampalen Gyrus, im posterioren Cingulum, im<br />
postzentralen Gyrus, im präzentralen Gyrus, im Putamen, im superioren<br />
temporalen Gyrus und im Thalamus auftreten. Linskhemisphärisch war der<br />
gleiche Effekt im Cuneus, im Hippocampus und im Lobulus parietalis superior<br />
zu beobachten, während rechtshemisphärisch der linguale Gyrus, der<br />
Precuneus und der supramarginale Gyrus stärkere BOLD-Signale aussendeten.<br />
Da Nichtraucher diesen Reiz subjektiv als unangenehmer bewerteten<br />
und die eingeschlossene Rauchergruppe nicht durch Entzugscraving beeinträchtigt<br />
war, war eine stärkere Beteiligung von Hirnarealen zu erwarten,<br />
die mit negativen bzw. positiven Emotionen und kognitiver Informationsverarbeitung<br />
(Bewertung, Planen), jedoch weniger mit Rauchverlangen in<br />
Verbindung gebracht werden. Die ausgeprägteren BOLD-Signale von mit<br />
Craving assoziierten Regionen wie dem Nucleus accumbens, der Insula,<br />
dem präfrontalen Kortex oder dem anterioren Cingulum bei Nichtrauchern<br />
können entsprechend nicht als Korrelate des Rauchverlangens interpretiert<br />
werden. Betrachtet man das Verlangen zu Rauchen jedoch ebenfalls als eine<br />
Emotion, so würden die genannten Regionen Teil des emotionsverarbeitenden<br />
Systems und in Bewertungsprozesse involviert sein. Diese Ansicht ist<br />
bereits von verschiedenen Autoren vertreten worden (Anderson, et al.,
Integration und Diskussion der Daten<br />
2003; Rolls et al., 2003). Ein durch Nichtraucher als unangenehm bewerteter<br />
Reiz könnte dann die gleichen oder ähnliche Regionen aktivieren wie<br />
empfundenes Craving bei Rauchern im Entzug. Die signifikant größeren<br />
BOLD-Signale in Schmerzarealen bei Nichtrauchern könnten darauf zurückzuführen<br />
sein, dass bei Rauchern durch den regelmäßigen Zigarettenkonsum<br />
eine Habituation bezüglich der trigeminalen Aspekte des Nikotins<br />
stattgefunden haben könnte. Dieser Effekt wird durch die EEG-Daten gestützt,<br />
die gezeigt haben, dass das Muster neuronaler kortikaler Aktivität<br />
sich in trigeminalen Konzentrationen unter S-Nikotin im Vergleich zu olfaktorischen<br />
Konzentrationen nicht verändert. Auch die in der EEG-<br />
Untersuchung bestimmten Schwellen unterstützen diese Annahme.<br />
Unterschiede in der Wahrnehmung von S- und R-Nikotin<br />
Bei dem Vergleich der Aktivierungsmuster nach Applikation der unterschiedlichen<br />
Nikotinenantiomere, der für jede Untersuchungsgruppe getrennt<br />
erfolgte, erwiesen sich die Nichtraucher als diejenigen, deren Gehirn<br />
die beiden Substanzen durch unterschiedliche BOLD-Signale am Besten<br />
unterscheiden konnten. Die Unterschiede zeigten sich sowohl in Schmerzarealen<br />
als auch im ventralen Striatum und im präfrontalen Kortex. Aufgrund<br />
der deutlich höher liegenden trigeminalen Schwellen des R-Nikotins<br />
waren erstgenannte Differenzen in trigeminalen Regionen zu erwarten. Da<br />
Nichtraucher S-Nikotin außerdem konstant negativer bewerteten als R-<br />
Nikotin könnte dies erneut ein Hinweis auf eine Beteiligung von Arealen an<br />
Emotionen sein, die ursprünglich mit Craving assoziiert wurden. Bei Rauchern<br />
unterschieden sich die Reaktionen des Gehirns lediglich im präfrontalen<br />
Kortex und in der Amygdala, während sich diese bei Entzügigen wiederum<br />
im ventralen Striatum, dem Hippocampus, dem Thalamus und dem<br />
präzentralen Gyrus heraus kristallisierten. Das Aktivierungsmuster der Raucher<br />
im Entzug näherte sich also dem der Nichtraucher wieder an, jedoch<br />
waren bei den abstinenten Rauchern die BOLD-Signale in den Schmerzarealen<br />
stärker ausgeprägt. Trotz der mehrfach berichteten generellen trigeminalen<br />
Sensibilisierung fielen die Unterschiede bei Rauchern im Entzug<br />
zwischen den beiden Enantiomeren in den typischen olfaktorischen und mit<br />
Schmerz assoziierten Hirnarealen geringer aus als bei Nichtrauchern. Dies<br />
könnte auf Generalisierungsprozesse von bereits mit S-Nikotin erfolgten<br />
185
186<br />
Integration und Diskussion der Daten<br />
Konditionierungsprozessen auf R-Nikotin zurückgeführt werden. Die sensiblere<br />
Wahrnehmung von trigeminalen Eigenschaften, ein früheres Auftreten<br />
schmerzhafter Aspekte bereits in geringen Konzentrationen und eine<br />
damit einhergehende verringerte olfaktorische und trigeminale Differenzierungsfähigkeit<br />
der beiden Isomere durch die Entzugsgruppe wären so denkbar.<br />
Die Habituation auf S-Nikotin durch den anhaltenden und regelmäßigen<br />
Kontakt bei Rauchern könnte sich hingegen auch auf andere trigeminale<br />
Reize auswirken. Unterschiedliche Aktivierungsmuster von S- und R-<br />
Nikotin in der Amygdala, im anterioren Cingulum, im Nucleus accumbens<br />
und im Hippocampus zeigten sich wie erwartet nur bei Rauchern, jedoch<br />
nicht bei Nichtrauchern nicht festgestellt werden. Somit könnten diese Regionen<br />
entweder mit Craving oder mit speziell mit S-Nikotin in Verbindung<br />
stehenden Konditionierungsprozesse in Zusammenhang stehen.<br />
Unterschiede in der Wahrnehmung von S-Nikotin zwischen Rauchern und<br />
Rauchern im Entzug<br />
Der Vergleich der Reaktionen von Rauchern und Rauchern im Entzug auf<br />
S-Nikotin unterstützte noch einmal die Hypothese einer erhöhten trigeminalen<br />
Sensibilität nach drei Tagen Abstinenz. Auch diese Effekte fanden sich<br />
wiederum fast ausschließlich in den olfaktorischen bzw. niedrigen Konzentrationen.<br />
Regionen, die bei den beiden Gruppen spezifisch auf S-Nikotin<br />
unterschiedlich reagierten, konnten nicht identifiziert werden. Jedoch zeigten<br />
sich für die beiden Nikotinenantiomere signifikante Differenzen in Regionen,<br />
die dem Gedächtnis (Hippocampus, parahippocampaler Gyrus),<br />
dem Craving bzw. der Emotionsverarbeitung (Insula, Nucleus accumbens,<br />
präzentraler Gyrus, Amygdala) und der Schmerzverarbeitung (postzentraler<br />
Gyrus, präzentraler Gyrus) zugerechnet werden. Die erhöhte trigeminale<br />
Sensibilität im Entzug zeigte sich also erneut. Die verbliebenen Regionen<br />
wurden zudem zur weiteren Absicherung ihrer Relevanz für das Craving<br />
mit den subjektiven Ratings korreliert. Übereinstimmend mit Besson et al.<br />
(2007), Due et al. (2002), McClernon et al. (2005) und McClernon et al.<br />
(2007) kristallisierten sich dabei die Insula und der präfrontale Kortex als<br />
mit dem Craving assoziiert heraus. Auch der von diesen Arbeitsgruppen als<br />
relevant erachtete Nucleus accumbens zeigte tendenziell einen Zusammenhang<br />
mit dem subjektiv empfundenen Verlangen zu Rauchen. Zusätzlich
Integration und Diskussion der Daten<br />
ergab die Analyse eine Bedeutung des linken inferioren temporalen Gyrus,<br />
was bisher noch von keiner Gruppe berichtet wurde. Dieses Areal wird<br />
primär mit Gedächtnisfunktionen im visuellen Bereich assoziiert (Orrison<br />
Jr., 2008, S. 82), so dass eine Beteiligung dieser Gehirnregion am Craving<br />
darauf hindeutet, dass möglicherweise auch visuelle Repräsentationen<br />
suchtassoziierter Reize an der Modulation des Rauchverlangens beteiligt<br />
sein könnten. Diese These wird auch durch den statistischen Trend der Korrelation<br />
des subjektiven Cravings mit dem rechten mittleren okzipitalen<br />
Gyrus, der ebenfalls bisher von keiner Forschergruppe als relevant berichtet<br />
wurde, unterstützt. Ebenfalls erstmalig mit dem Rauchverlangen wurde das<br />
linke Cingulum in Verbindung gebracht, das mit der Verarbeitung unangenehmer<br />
Emotionen in Verbindung gebracht wird (Fujiwara, Hirao, Namiki,<br />
Yamada, Shimizu, Fukuyama, Hayashi & Murai, 2007). Das Craving konnte<br />
also entsprechend der Hypothese in Regionen angesiedelt werden, die<br />
vorwiegend mit der Emotionsverarbeitung assoziiert waren. Craving könnte<br />
also eine spezielle emotionale Reaktion sein, die neben den bekannten Gefühlen<br />
wie Traurigkeit oder Ekel erzeugt wird. Zudem konnten in Übereinstimmung<br />
mit Voruntersuchungen (Besson et al., 2007; Due et al., 2002;<br />
McClernon et al., 2005; McClernon et al., 2007) der rechte mittleren frontalen<br />
Gyrus und tendenziell das linke Cerebellum, sowie der linken Thalamus<br />
mit dem Craving in Zusammenhang gebracht werden. Im trigeminalen Bereich<br />
traten keine Unterschiede auf, die mit der untersuchten Variable korrelierten,<br />
was auf eine untergeordnete oder unter Einbezug der Korrelation<br />
des Rauchverlangens und der Hedonik sogar hemmende Rolle des Schmerzes<br />
auf das Craving hindeutet.<br />
Da die Daten aus der Auswertung der psychophysischen Ratings sich weitgehend<br />
mit den Ergebnissen der EEG-Untersuchung deckten, wird hier auf<br />
eine erneute Diskussion verzichtet.<br />
187
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Integration und Diskussion der Daten<br />
7.4. Integration der Untersuchungsergebnisse<br />
Abschließend sollen die Ergebnisse dieser Studie noch einmal kurz und<br />
prägnant zusammengefasst werden. Es kristallisierte sich heraus, dass Raucher<br />
durch den Zigarettenkonsum offenbar an trigeminale Aspekte habituieren,<br />
während sie im Entzug eine noch deutlich ausgeprägtere Sensibilität für<br />
intranasal verabreichte Schmerzreize zeigten als Nichtraucher. Zudem stand<br />
das Craving sowohl bei Nichtentzügigen als auch am dritten Tag der Abstinenz<br />
mit der Hedonik des applizierten Reizes in Zusammenhang. Je angenehmer<br />
der Reiz eingeschätzt wurde, desto stärker sehnten sie sich nach<br />
einer Zigarette. Weiterhin bemerkenswert war das Resultat, dass Nichtraucher<br />
und Raucher im Entzug mit ähnlichen Gehirnarealen auf die Applikation<br />
von S-Nikotin reagierten, während Raucher dies nicht taten. Da bei<br />
Nichtrauchern kein Entzug vorliegen konnte, aber ausgeprägte negative<br />
Emotionen berichtet bzw. negative hedonische Bewertungen abgegeben<br />
wurden, könnte es sich bei Craving ebenfalls um eine starke emotionale<br />
Reaktion handeln. Die Rolle des inferioren temporalen Kortex muss dabei<br />
noch geklärt werden. Insgesamt betrachtet, traten die geschilderten Ergebnisse<br />
sowohl in der EEG- als auch in der fMRT-Untersuchung fast betont in<br />
olfaktorischen Bereichen auf. Da bereits zwei Studien mit niedrigen bis<br />
mittleren trigeminalen S- und R-Nikotinreizen gearbeitet hatten, war es Ziel<br />
der vorliegenden Untersuchung, den Einfluss sehr hoher schmerzhafter<br />
Konzentrationen der beiden Substanzen zu untersuchen. Aufgrund der Ergebnisse<br />
dieses Experiments kann am wahrscheinlichsten von einer das<br />
Craving unterdrückenden Rolle schmerzhafter Reize ausgegangen werden.
8. Ausblick<br />
Ausblick<br />
Die vorliegende Studie konnte einerseits bereits bekannte Resultate aus<br />
Voruntersuchungen bestätigen. Gleichzeitig lieferte sie auch eine Reihe<br />
neuer Erkenntnisse, die bei Bestätigung durch weitere Studien aktuelle<br />
Vorgehensweisen in der Raucherentwöhnung in Frage stellen könnten. So<br />
würde die Bedeutung trigeminaler Aspekte erklären, warum sensory replacement<br />
zu einer Erhöhung der Erfolgsquote führte (s. Behm, Schur, Levin,<br />
Tashkin & Rose, 1993). Da sich der Zusammenhang zwischen den hedonischen<br />
Einschätzungen und dem empfundenen Craving sowie die gesteigerte<br />
trigeminale Sensitivität im Entzug nicht nur für Nikotinreize, sondern auch<br />
für eingesetzte Kontrollreize zeigte, kann von einem Generalisierungseffekt<br />
auf verschiedene Reizklassen ausgegangen werden. Die vorliegenden Ergebnisse<br />
liefern somit eine Erklärung, warum auch Methoden wie der Citric<br />
Inhaler, die keine Nikotinanaloga sind, bei der Raucherentwöhnung helfen.<br />
Eine weitere Möglichkeit könnte auch die Stimulation von Hirnarealen,<br />
deren Aktivierung sich als hemmend für Craving gezeigt hat, durch moderne<br />
Hirnstimulationsverfahren, wie zum Beispiel die Magnetstimulation (s.<br />
z.B. Boggio, Liguori, Sultani, Rezende, Fecteau & Fregni, 2009; Eichhammer,<br />
Johann, Kharraz, Binder, Pittrow, Wodarz & Hajak, 2003), darstellen.<br />
Ein weiterer Ansatzpunkt könnte die Sensibilisierung für Schmerzreize im<br />
Entzug sein. In dieser Untersuchung lag der Fokus ausschließlich auf nasalen<br />
Reizen. Weitere Untersuchungen könnten sich mit der generellen<br />
Schmerzsensibilisierung im Entzug beschäftigen, die in Verbindung mit der<br />
geringeren Frustrationstoleranz und Reizbarkeit ebenfalls Rückfall fördernd<br />
sein könnte. Sollte sich das Ergebnis auf breiter Ebene bestätigen, müsste<br />
dies auch im Rahmen von Entwöhnungsprogrammen z.B. in Form von<br />
Psychoedukation Raum finden. Gleichzeitig könnte dieser Effekt der<br />
Schmerzsensibilisierung möglicherweise jedoch auch zur Rückfallprophylaxe<br />
genutzt werden. Entwöhner könnten für Warnzeichen des Cravings<br />
sensibilisiert werden, denen sie dann mit dem Schnüffeln an einem unangenehmen,<br />
nozizeptiven bzw. schmerzhaften Geruch mit starken trigeminalen<br />
Eigenschaften begegnen könnten, bevor sie zur Zigarette greifen. Das Ergebnis,<br />
dass angenehme Reize das Craving sowohl bei aktuell Rauchenden<br />
189
190<br />
Ausblick<br />
als auch im Entzug steigern, könnte den Einsatz von Genusstrainings im<br />
Rahmen der Entwöhnung in Frage stellen. Die Aussage vieler Raucher, vor<br />
allem unter dem Einfluss von Alkohol, nach dem Essen oder einer Tasse<br />
Kaffee rückfällig zu werden, unterstützt das vorliegende Ergebnis. Auch<br />
hier sind weitere Studien erforderlich, um zu überprüfen, ob eventuell generell<br />
angenehme Reize einschließlich angenehmer Aktivitäten die Rückfallgefahr<br />
erhöhen oder ob dieser Befund eher auf einen Epieffekt einer nozizeptiven<br />
bzw. schmerzhaften Reizung zurückzuführen ist. Letzteres würde<br />
wiederum für den Einsatz von Hirnstimulationsmethoden (s.o.) sprechen.<br />
Bei Zutreffen der ersten Hypothese und unter der Berücksichtigung, dass es<br />
sich bei Craving um eine spezielle emotionale Reaktion handeln könnte,<br />
müsste das Vorgehen in Raucherentwöhnungskursen angepasst werden.<br />
Eine Aneinanderreihung von positiv bewerteten Reizen in Form von Verstärkerketten<br />
(z.B. Essen, Rotwein, Dessert) könnte, statt wie bisher angenommen,<br />
nicht zu einer Reduzierung, sondern zu einer Steigerung des empfundenen<br />
Cravings führen. So würde sich statt der Empfehlung alternativer<br />
Genussreize (z.B. Schokolade, Rotwein) die Methode der Konfrontation mit<br />
Reaktionsverhinderung in Anlehnung an das weit verbreitete Vorgehen bei<br />
Angst- oder Zwangserkrankungen (Hamm, 2005; Lakatos & Reinecker,<br />
2007) zur Bewältigung des Rauchverlangens empfehlen. So könnte neben<br />
der Steigerung der Selbstwirksamkeitserwartung (Bandura, 1982) und einer<br />
kognitiven Umstrukturierung eine Veränderung zugrunde liegender neuronaler<br />
Strukturen eingeleitet werden.<br />
Zusammenfassend ist es die Meinung der Autorin, dass interdisziplinäre<br />
Studien mit bildgebenden Verfahren trotz eines zunehmenden Trends nach<br />
wie vor zu wenig durchgeführt werden bzw. die wenigen Untersuchungen<br />
nicht ausreichend beachtet werden. So zogen zum Beispiel die von Naquvi<br />
et al. (2007) geschilderten Fallberichte zu den Auswirkungen eines Insulainfarkts<br />
auf das Craving bzw. den Rauchstopp keine therapeutischen Konsequenzen<br />
nach sich. Insgesamt ist eine weitere und profunde Analyse des<br />
Zusammenwirkens von Hirnarealen, die mit Sucht, Craving und der sensorischen<br />
Repräsentation des Suchtstoffs Nikotin verbunden sind, erforderlich,<br />
um sowohl psychologische als auch medizinische Interventionen<br />
verbessern zu können.
Ausblick<br />
Man könnte sagen, daß das wahre Leben beim Unscheinbaren beginnt – wo<br />
Veränderungen stattfinden, die uns geringfügig und unendlich klein erscheinen.<br />
Das wahre Leben wird nicht dort gelebt, wo sich große äußere<br />
Umwälzungen ereignen – wo Menschen umherziehen, aufeinanderstoßen,<br />
kämpfen und einander erschlagen; es wird nur dort gelebt, wo diese winzigen,<br />
winzigen unendlich kleinen Veränderungen stattfinden.<br />
Leo Tolstoj<br />
1828 - 1910<br />
191
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237
Verzeichnis der Abbildungen<br />
Verzeichnis der Abbildungen<br />
Abb. 1: Kriterien der Substanzabhängigkeit nach DSM-IV ................ 21<br />
Abb. 2: Kriterien des Substanzmissbrauchs nach DSM-IV ................. 22<br />
Abb. 3: Kriterien des Nikotinentzugs nach DSM-IV........................... 24<br />
Abb. 4: Chemische Struktur des Nikotins............................................ 33<br />
Abb. 5: Struktur der Acetylcholinrezeptoren....................................... 39<br />
Abb. 6: Aufbau des Acetylcholinrezeptors .......................................... 42<br />
Abb. 7: Die wichtigsten limbischen Zentren des menschlichen Gehirns<br />
........................................................................................ 49<br />
Abb. 8: Das trigeminale System .......................................................... 68<br />
Abb. 9: Überblick über den Untersuchungsablauf............................. 101<br />
Abb. 10: Bei der EEG-Untersuchung eingesetztes Olfaktometer ........ 102<br />
Abb. 11: Funktionsprinzip des Olfaktometers ..................................... 104<br />
Abb. 12: Ratingverfahren der EEG-Untersuchung und der<br />
funktionellen Magnetresonanztomographie.......................... 110<br />
Abb. 13: Aufbau des Sniffin´Sticks Test ............................................. 113<br />
Abb. 14: Vergleich der Untersuchungsgruppen hinsichtlich der Amplitude<br />
p2 .................................................................................. 129<br />
Abb. 15: Vergleich der Untersuchungsgruppen hinsichtlich der Latenzzeit<br />
p2.................................................................................... 132<br />
Abb. 16: Signifikante Lateralisierungstendenzen getrennt<br />
nach Untersuchungsgruppen ................................................. 134<br />
Abb. 17: Signifikante Frontalisierungstendenzen bei Rauchern<br />
..................................................................................... 135<br />
Abb. 18: Signifikante Frontalisierungstendenzen bei Nichtrauchern<br />
..................................................................................... 136<br />
Abb. 19: Signifikante Frontalisierungstendenzen bei Rauchern<br />
im Entzug .................................................................... 137<br />
Abb. 20: Zusammenhang zwischen Craving und hedonischer<br />
Einschätzung bei Rauchern................................................... 142<br />
Abb. 21: Zusammenhang zwischen Craving und hedonischer<br />
Einschätzung bei Rauchern im Entzug ................................. 142<br />
Abb. 22: Aufbau des fMRT-tauglichen Olfaktometers........................ 149<br />
239
240<br />
Verzeichnis der Abbildungen<br />
Abb. 23: Experimentelle Anordnung der funktionellen Magnetresonanztomographie<br />
.......................................................150<br />
Abb. 24: Stimulationsprotokoll der olfaktorischen Sequenz ................152<br />
Abb. 25: Stimulationsprotokoll der trigeminalen Sequenz...................152<br />
Abb. 26: Aktivierungen nach Applikation olfaktorischer Reize ..........159<br />
Abb. 27: Aktivierungen nach Applikation trigeminaler Reize .............163<br />
Abb. 28: Gemittelter BOLD-Verlauf im rechten Hippocampus<br />
bei Rauchern im Entzug nach der Applikation<br />
von R- und S-Nikotin im Vergleich ......................................165
Verzeichnis der Tabellen<br />
Verzeichnis der Tabellen<br />
Tab. 1: Abfolge der Reize in der olfaktorischen und trigeminalen<br />
Sequenz in der EEG-Untersuchung................................ 117<br />
Tab. 2: Amplitudenmaxima für olfaktorisches S-Nikotin<br />
über alle Untersuchungsgruppen ............................................. 122<br />
Tab. 3: Amplitudenmaxima für olfaktorisches R-Nikotin<br />
über alle Untersuchungsgruppen ............................................. 122<br />
Tab. 4: Amplitudenmaxima für Rose über alle Untersuchungsgruppen.........................................................................<br />
122<br />
Tab. 5: Amplitudenmaxima für trigeminales S-Nikotin über<br />
alle Untersuchungsgruppen...................................................... 123<br />
Tab. 6: Amplitudenmaxima für olfaktorisches R-Nikotin<br />
über alle Untersuchungsgruppen ............................................. 123<br />
Tab. 7: Amplitudenmaxima für CO2 über alle Untersuchungsgruppen123<br />
Tab. 8: Vergleich der Amplituden Raucher vs. Nichtraucher .............. 126<br />
Tab. 9: Vergleich der Amplituden Raucher vs. Raucher im Entzug .... 127<br />
Tab. 10: Vergleich der Latenzzeiten Raucher vs. Raucher im Entzug... 131<br />
Tab. 11: Frontalisierungstendenzen bei Rauchern im Entzug................ 138<br />
Tab. 12: Vergleich der Mittelwerte der Schwellenbestimmung<br />
über die Untersuchungsgruppen .............................................. 139<br />
Tab. 13: Mittelwerte der Variablen Craving und Hedonik für<br />
Raucher und Raucher im Entzug ............................................. 143<br />
Tab. 14: Abfolge der Reize in der olfaktorischen und trigeminalen<br />
Sequenz in der fMRT-Untersuchung ............................. 151<br />
Tab. 15: Aktivierte Hirnregionen nach der Applikation olfaktorischer<br />
Reize ........................................................................................ 158<br />
Tab. 16: Signifikante BOLD-Signale nach Applikation von CO2 ......... 160<br />
Tab. 17: Signifikante BOLD-Signale nach Applikation von<br />
trigeminalem S- und R-Nikotin ............................................... 162<br />
Tab. 18: Rangfolge der Einzelreize hinsichtlich ihrer hedonischen<br />
Bewertung nach Untersuchungsgruppen getrennt<br />
betrachtet ....................................................................... 170<br />
241
Anhang<br />
Anhang<br />
243
244<br />
Anhang<br />
C3 C4 Fz Pz Cz<br />
P1 0,018993 0,014373 0,018173 0,022407 0,022453<br />
N1 -0,022600 -0,036073 -0,037760 -0,020227 -0,033140<br />
P2 0,073247 0,064407 0,076820 0,086147 0,084960<br />
P1N1 0,041593 0,050447 0,053267 0,039993 0,055593<br />
N1P2 0,095847 0,100480 0,114580 0,105433 0,117160<br />
Tabelle A1: Amplitudenmaxima für olfaktorisches S-Nikotin für die Gruppe Raucher im<br />
Entzug<br />
C3 C4 Fz Pz Cz<br />
P1 0,010780 0,010973 0,012227 0,014380 0,019620<br />
N1 -0,029927 -0,036720 -0,031400 -0,024700 -0,034740<br />
P2 0,063187 0,059953 0,068300 0,077680 0,077200<br />
P1N1 0,040707 0,047693 0,043627 0,039080 0,054360<br />
N1P2 0,093113 0,096673 0,099700 0,102380 0,111940<br />
Tabelle A2: Amplitudenmaxima für olfaktorisches R-Nikotin für die Gruppe Raucher im<br />
Entzug<br />
C3 C4 Fz Pz Cz<br />
P1 0,014547 0,013967 0,018947 0,018387 0,020507<br />
N1 -0,020660 -0,027720 -0,028240 -0,027093 -0,027847<br />
P2 0,068113 0,065813 0,062127 0,081660 0,082380<br />
P1N1 0,035207 0,041687 0,047187 0,045480 0,048353<br />
N1P2 0,088773 0,093533 0,093607 0,108753 0,110227<br />
Tabelle A3: Amplitudenmaxima für Rose für die Gruppe Raucher im Entzug<br />
C3 C4 Fz Pz Cz<br />
P1 0,010513 0,017740 0,017660 0,018333 0,017320<br />
N1 -0,016047 -0,022607 -0,022767 -0,023013 -0,024273<br />
P2 0,056920 0,060813 0,055893 0,088260 0,062540<br />
P1N1 0,026560 0,040347 0,040427 0,041347 0,041353<br />
N1P2 0,072967 0,083420 0,078660 0,111273 0,086567<br />
Tabelle A4: Amplitudenmaxima für olfaktorisches S-Nikotin für die Gruppe Raucher
Anhang<br />
C3 C4 Fz Pz Cz<br />
P1 0,016807 0,018707 0,012387 0,023080 0,015287<br />
N1 -0,017853 -0,020040 -0,017500 -0,024013 -0,018507<br />
P2 0,043333 0,058593 0,047027 0,074920 0,050207<br />
P1N1 0,034660 0,038747 0,029887 0,047093 0,033793<br />
N1P2 0,061187 0,078633 0,064527 0,098933 0,068713<br />
Tabelle A5: Amplitudenmaxima für olfaktorisches R-Nikotin für die Gruppe Raucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,007667 0,021253 0,011100 0,017560 0,012993<br />
N1 -0,022513 -0,015593 -0,022573 -0,016447 -0,022840<br />
P2 0,049920 0,061553 0,054907 0,082867 0,062880<br />
P1N1 0,030180 0,036847 0,033673 0,034007 0,035833<br />
N1P2 0,072433 0,077147 0,077480 0,099313 0,085720<br />
Tabelle A6: Amplitudenmaxima für Rose für die Gruppe Raucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,013693 0,017700 0,019500 0,036713 0,024647<br />
N1 -0,028953 -0,030667 -0,023427 -0,026113 -0,027573<br />
P2 0,084447 0,099833 0,073820 0,144653 0,110873<br />
P1N1 0,042647 0,048367 0,042927 0,062827 0,048493<br />
N1P2 0,113400 0,130500 0,097247 0,170767 0,131053<br />
Tabelle A7: Amplitudenmaxima für olfaktorisches S-Nikotin für die Gruppe Nichtraucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,025727 0,021213 0,029033 0,035380 0,025513<br />
N1 -0,021787 -0,020673 -0,022647 -0,021827 -0,023513<br />
P2 0,070120 0,080900 0,068307 0,128027 0,084820<br />
P1N1 0,047513 0,041887 0,051680 0,066060 0,049027<br />
N1P2 0,091907 0,101573 0,090953 0,142727 0,108333<br />
Tabelle A8: Amplitudenmaxima für olfaktorisches R-Nikotin für die Gruppe Nichtraucher<br />
245
246<br />
Anhang<br />
C3 C4 Fz Pz Cz<br />
P1 0,021087 0,023300 0,032067 0,025373 0,032353<br />
N1 -0,028740 -0,032580 -0,023820 -0,040140 -0,028900<br />
P2 0,068380 0,087767 0,080287 0,152287 0,098440<br />
P1N1 0,049827 0,055880 0,050007 0,065513 0,061253<br />
N1P2 0,097120 0,120347 0,098727 0,192427 0,127340<br />
Tabelle A9: Amplitudenmaxima für Rose für die Gruppe Nichtraucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,022760 0,019667 0,021493 0,025293 0,021473<br />
N1 -0,030753 -0,032740 -0,025987 -0,029033 -0,039127<br />
P2 0,091680 0,088840 0,100940 0,096853 0,109073<br />
P1N1 0,053513 0,052407 0,047480 0,054327 0,060600<br />
N1P2 0,122433 0,121580 0,126927 0,125887 0,148200<br />
Tabelle A10: Amplitudenmaxima für trigeminales S-Nikotin für die Gruppe Raucher im Entzug<br />
C3 C4 Fz Pz Cz<br />
P1 0,009653 0,012667 0,017980 0,014100 0,019160<br />
N1 -0,033140 -0,032807 -0,020687 -0,024440 -0,027253<br />
P2 0,090480 0,088013 0,099393 0,104653 0,120493<br />
P1N1 0,042793 0,045473 0,040967 0,038540 0,046413<br />
N1P2 0,123620 0,120820 0,120140 0,129093 0,147747<br />
Tabelle A11: Amplitudenmaxima für trigeminales R-Nikotin für die Gruppe Raucher im<br />
Entzug<br />
C3 C4 Fz Pz Cz<br />
P1 0,021667 0,026793 0,021687 0,025253 0,023113<br />
N1 -0,030787 -0,032160 -0,028740 -0,034460 -0,039907<br />
P2 0,094533 0,088067 0,109920 0,102193 0,116633<br />
P1N1 0,052453 0,058953 0,050427 0,059713 0,063020<br />
N1P2 0,125320 0,120227 0,138660 0,136653 0,156540<br />
Tabelle A12: Amplitudenmaxima für CO2 für die Gruppe Raucher im Entzug
Anhang<br />
C3 C4 Fz Pz Cz<br />
P1 0,015787 0,018873 0,016273 0,019480 0,017920<br />
N1 -0,023933 -0,036213 -0,024233 -0,035540 -0,033393<br />
P2 0,079607 0,082500 0,065660 0,134420 0,092093<br />
P1N1 0,039720 0,055087 0,040507 0,055020 0,051313<br />
N1P2 0,103540 0,118713 0,089893 0,169960 0,125487<br />
Tabelle A13: Amplitudenmaxima für trigeminales S-Nikotin für die Gruppe Raucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,011513 0,013260 0,019227 0,019167 0,017580<br />
N1 -0,036253 -0,035413 -0,015427 -0,026860 -0,027193<br />
P2 0,076020 0,094013 0,115520 0,130173 0,100480<br />
P1N1 0,034207 0,048673 0,034653 0,045767 0,044773<br />
N1P2 0,098713 0,129427 0,090447 0,156793 0,127673<br />
Tabelle A14: Amplitudenmaxima für trigeminales R-Nikotin für die Gruppe Raucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,012693 0,014460 0,015260 0,018860 0,012020<br />
N1 -0,021940 -0,029073 -0,020953 -0,023367 -0,026460<br />
P2 0,085660 0,097773 0,093380 0,142433 0,097733<br />
P1N1 0,034633 0,043533 0,036213 0,042227 0,038480<br />
N1P2 0,107600 0,126847 0,114333 0,165800 0,124193<br />
Tabelle A15: Amplitudenmaxima für CO2 für die Gruppe Raucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,009460 0,010247 0,020147 0,013800 0,015553<br />
N1 -0,036340 -0,053380 -0,023540 -0,042480 -0,040533<br />
P2 0,091860 0,111293 0,086127 0,146680 0,121240<br />
P1N1 0,045800 0,059013 0,043687 0,059780 0,056087<br />
N1P2 0,138273 0,157567 0,109667 0,189160 0,161773<br />
Tabelle A16: Amplitudenmaxima für trigeminales S-Nikotin für die Gruppe Nichtraucher<br />
247
248<br />
Anhang<br />
C3 C4 Fz Pz Cz<br />
P1 0,016193 0,010560 0,025207 0,010473 0,012820<br />
N1 -0,030320 -0,049380 -0,019107 -0,039973 -0,036147<br />
P2 0,104047 0,118727 0,089540 0,134693 0,118813<br />
P1N1 0,040020 0,064047 0,044313 0,050447 0,048967<br />
N1P2 0,121893 0,168107 0,108647 0,174667 0,154960<br />
Tabelle A17: Amplitudenmaxima für trigeminales R-Nikotin für die Gruppe Nichtraucher<br />
C3 C4 Fz Pz Cz<br />
P1 0,007527 0,014813 0,019553 0,016460 0,011300<br />
N1 -0,040113 -0,054593 -0,021600 -0,040267 -0,054493<br />
P2 0,082633 0,115853 0,091287 0,136200 0,111700<br />
P1N1 0,047640 0,069407 0,049573 0,056727 0,060540<br />
N1P2 0,122747 0,170447 0,117467 0,176467 0,158220<br />
Tabelle A18: Amplitudenmaxima für CO2 für die Gruppe Nichtraucher<br />
Amplitude F-Wert Anzahl der Frei-<br />
heitsgrade<br />
Signifikanz<br />
S-Nikotin P2 3,07 1 0,057<br />
S-Nikotin, N1P2 2,78 1 0,074<br />
R-Nikotin, P2 3,51 1 0,039*<br />
R-Nikotin, N1P2 2,76 1 0,075<br />
Rose, P2 4,67 1 0,015*<br />
Rose, N1P2 3,64 1 0,035*<br />
Tabelle A19: Vergleich der olfaktorischen Amplituden über alle Untersuchungsgruppen
UNIVERSITY OF BAMBERG PRESS<br />
Die Nikotinabhängigkeit ist von großer Bedeutung für die aktuelle<br />
Gesellschaft, weil sie die Nummer eins der vermeidbaren Todesursachen<br />
unserer Zeit ist. Viele Mechanismen, die ihr zugrunde liegen,<br />
werden in neuerer Zeit auch mit der Pathophysiologie verschiedener<br />
psychiatrischer Störungsbilder wie z.B. Morbus Alzheimer<br />
oder ADHS in Verbindung gebracht. Nikotinerg-cholinerge Schaltkreise<br />
stellen sich außerdem zunehmend als entscheidender Faktor<br />
für kognitive Prozesse wie Gedächtnis, Lernen, Aufmerksamkeit<br />
und Wahrnehmung heraus. Viele grundlegende Mechanismen sind<br />
jedoch nach wie vor unbekannt.<br />
Die vorliegende Arbeit beschäftigt sich mit neurophysiologischen<br />
und psychophysiologischen Reaktionen von Rauchern, Rauchern<br />
im Entzug und Nichtrauchern auf olfaktorische und trigeminale<br />
Nikotinreize sowie auf Kontrollsubstanzen. Hierfür wurden die<br />
evozierten Antworten mit EEG und funktioneller Magnetresonanztomographie<br />
aufgezeichnet und analysiert. Der kombinierte<br />
Einsatz verschiedenster Verfahren zur Messung von Reaktionen<br />
des menschlichen Gehirns in verschiedenen Zuständen (Rauchen,<br />
Nichtrauchen, im Entzug) auf intranasale Reize ist neuartig und<br />
liefert neben der Bestätigung bereits vorliegender Ergebnisse eine<br />
Reihe neuer Erkenntnisse, die sowohl für die Forschung als auch für<br />
die Praxis wertvolle Anregungen geben können.<br />
ISBN 978-3-923507-69-6<br />
ISSN 1866-8674<br />
Preis 16,80 Euro
Nachschlagewerk zum Thema E-Zigaretten<br />
48 Monoamine Oxidase Inhibitors Allow Locomotor<br />
and Rewarding Responses to Nicotine.
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Original Article<br />
Neuropsychopharmacology (2006) 31, 1704–1713. doi:10.1038/sj.npp.1300987;<br />
published online 14 December 2005<br />
Preclinical Research<br />
Monoamine Oxidase Inhibitors Allow<br />
Locomotor and Rewarding Responses to<br />
Nicotine<br />
Anne-Sophie Villégier 1,2 , Lucas Salomon 1 , Sylvie Granon 3 , Jean-<br />
Pierre Changeux 3 , James D Belluzzi 2 , Frances M Leslie 2 and<br />
Jean-Pol Tassin 1<br />
1 Inserm U.114, Collège de France, Place Marcelin Berthelot, Paris, France<br />
2 Department of Pharmacology, School of Medicine and Transdisciplinary<br />
Tobacco Use Research Center, University of California, Irvine, CA, USA<br />
3 Laboratoire de Neurobiologie Moléculaire, C.N.R.S., Récepteurs et Cognition,<br />
Institut Pasteur, Paris, France<br />
Correspondence: Dr J-P Tassin, Inserm U.114, Collège de France, 11, Place<br />
Marcelin Berthelot, 75231 Paris, France. Tel: +33 1 44271231; Fax: +33 1<br />
44271260; E-mail: jean-pol.tassin@college-de-france.fr<br />
Received 29 July 2005; Revised 28 September 2005; Accepted 21 October 2005;<br />
Published online 14 December 2005.<br />
Abstract<br />
Subscribe<br />
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Although nicotine is generally considered to be the main<br />
compound responsible for the addictive properties of<br />
tobacco, experimental data indicate that nicotine does not<br />
exhibit all the characteristics of other abused substances,<br />
such as psychostimulants and opiates. For example, nicotine<br />
is only a weak locomotor enhancer in rats and generally fails<br />
to induce a locomotor response in mice. This observation<br />
contradicts the general consensus that all drugs of abuse<br />
release dopamine in the nucleus accumbens, a subcortical<br />
structure, and thus increase locomotor activity in rodents.<br />
Because tobacco smoke contains monoamine oxidase<br />
inhibitors (MAOIs) and decreases MAO activity in smokers, we<br />
have combined MAOIs with nicotine to determine whether it<br />
is possible to obtain a locomotor response to nicotine in<br />
C57Bl6 mice. Among 15 individual or combined MAOIs,<br />
including harmane, norharmane, moclobemide, selegiline,<br />
pargyline, clorgyline, tranylcypromine and phenelzine, only<br />
irreversible inhibitors of both MAO-A and -B<br />
(tranylcypromine, phenelzine, and clorgyline+selegiline)<br />
allowed a locomotor response to nicotine. The locomotor<br />
stimulant interaction of tranylcypromine and nicotine was<br />
absent in 2-nicotinic acetylcholine receptor subunit<br />
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Abstract<br />
INTRODUCTION<br />
MATERIALS AND<br />
METHODS<br />
RESULTS<br />
DISCUSSION<br />
CONCLUSION<br />
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Acknowledgements<br />
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knockout mice. Finally, it was found that, whereas naïve rats<br />
did not readily self-administer nicotine (10 g/kg/injection), a<br />
robust self-administration of nicotine occurred when animals<br />
were pretreated with tranylcypromine (3 mg/kg). Our data<br />
suggest that MAOIs contained in tobacco and tobacco smoke<br />
act in synergy with nicotine to enhance its rewarding effects.<br />
Keyw ords: MAOIs, nicotine, locomotor activ ity, 2 nAChR subunit knockout,<br />
self-administration<br />
INTRODUCTION<br />
Top<br />
Drugs of abuse, such as D-amphetamine, cocaine, morphine, or<br />
heroin, share the ability to cause addiction in humans and to<br />
increase release of dopamine (DA) in the nucleus accumbens (Di<br />
Chiara and Imperato, 1988; Vezina et al, 1989; Pontieri et al, 1995;<br />
Koob, 1998; Robbins and Everitt, 1999). The same drugs induce<br />
locomotor hyperactivity, behavioral sensitization, conditioned place<br />
preference, and self-administration in rodents (Vezina et al, 1994;<br />
Pontieri et al, 1995; Biala and Langwinski, 1996; Carboni et al,<br />
2003; Li et al, 2003). Tobacco is a potent reinforcing agent in<br />
humans, and nicotine is generally considered to be the major<br />
compound responsible for its addictive properties (Dani and<br />
Heinemann, 1996; Balfour et al, 2000; Di Chiara, 2000). However,<br />
animal experiments indicate some discrepancies between the<br />
effects of nicotine and those of other drugs of abuse. For example,<br />
the stimulation of DA release in the nucleus accumbens after<br />
several nicotine injections remains controversial (Vezina et al,<br />
1992; Balfour et al, 1998; Di Chiara, 2000), and repeated nicotine<br />
treatments in rats induce a behavioral sensitisation, which vanishes<br />
quicker than for other drugs of abuse (Ksir et al, 1985; Villégier et<br />
al, 2003). Similarly, although self-administration of nicotine is<br />
observed in rodents (Corrigall and Coen, 1989; Donny et al, 1995;<br />
Martellotta et al, 1995; Shoaib et al, 1997; Caggiula et al, 2001)<br />
and monkeys (Goldberg et al, 1981; Wakasa et al, 1995), its<br />
development seems slower and weaker than for other drugs of<br />
abuse (Manzardo et al, 2002), and often needs facilitation by the<br />
use of food restriction (Corrigall et al, 2002; Rauhut et al, 2002) or<br />
cocaine pre-treatment (Picciotto et al, 1998). These differences<br />
suggest either that nicotine possesses both aversive and rewarding<br />
properties (Risinger and Brown, 1996; Shoaib et al, 2002), or that<br />
the addictive effects of tobacco are not only due to nicotine. A<br />
recent report suggests that agents in tobacco smoke can enhance<br />
nicotine self-administration (Belluzzi et al, 2005).<br />
One of the most striking differences between the effects of nicotine<br />
and those of other drugs of abuse concerns its locomotor effects.<br />
Although psychostimulants and opiates induce a substantial<br />
locomotor hyperactivity both in rats and mice, nicotine is a weak<br />
locomotor stimulant in rats and generally fails to induce locomotor<br />
hyperactivity in mice at any dose (Marks et al, 1983; Freeman et<br />
al, 1987; Kita et al, 1988; Damaj and Martin, 1993; Smolen et al,<br />
1994; Itzhak and Martin, 1999; Sparks and Pauly, 1999; Gaddnas<br />
et al, 2000; Castane et al, 2002).<br />
Tobacco and tobacco smoke are known to contain a number of<br />
compounds, among which monoamine oxidase inhibitors (MAOIs)<br />
have been the focus of special interest (Poindexter and Carpenter,<br />
1962; Breyer-Pfaff et al, 1996; Rommelspacher et al, 2002). Many<br />
authors have found that tobacco smokers, when compared to<br />
nonsmokers, have MAO-A and -B activities that are reduced by up<br />
to 40% (Oreland et al, 1981; Yu and Boulton, 1987; Berlin et al,<br />
1995; Fowler et al, 1996a, 1996b). Inhibition of monoamine<br />
oxidases (MAOs) by tobacco smoke does not result from the<br />
actions of nicotine (Carr and Basham, 1991), but from that of other
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compounds that are also present in other psychotropic plants<br />
(Uebelhack et al, 1998; Rommelspacher et al, 2002). We have<br />
recently shown that MAOI pretreatment allows the maintenance of<br />
locomotor behavioral sensitization to nicotine in rats (Villégier et al,<br />
2003), thus suggesting a role of MAOIs in the addictive properties<br />
of tobacco. We have therefore analyzed the consequences of<br />
different MAOI pretreatments on the locomotor response to nicotine<br />
in the mouse. First, different individual or combined MAOIs were<br />
injected into mice and their locomotor responses were analyzed for<br />
380 min. In another series of experiments, nicotine was injected at<br />
different times after MAOI(s) injection and locomotor effects of<br />
nicotine were calculated as the difference between responses with<br />
and without nicotine. Among the different MAOIs tested,<br />
tranylcypromine was found particularly effective in increasing<br />
locomotor response to nicotine. Tranylcypromine is a 'cyclized'<br />
amphetamine with an exposed amino group making that compound<br />
an irreversible mixed MAOI 5000 times as potent an MAOI as<br />
amphetamine (Zirkle and Kaiser, 1964).<br />
To verify that locomotor effects of nicotine were related to the<br />
stimulation of nicotinic acetylcholine receptors (nAChRs),<br />
locomotor activity was monitored in the presence of<br />
tranylcypromine in mice knockout for the 2 subunit ( 2-nAchR-<br />
KO). This subunit is part of the 4 2 nAChR, one of the most<br />
frequently found nAChR oligomers in mammalian brain (Pidoplichko<br />
et al, 1997; Charpantier et al, 1998).<br />
Finally, self-administration of nicotine was examined in rats<br />
pretreated with tranylcypromine.<br />
MATERIALS AND METHODS<br />
Top<br />
Subjects<br />
Mice Animals were adult male mice, on genetic background<br />
C57Bl6, weighing 35–45 g when experiments were conducted.<br />
Generation of the 2-nAChR subunit KO mice and their genetic<br />
background (C57Bl6) are as described previously by Picciotto et al<br />
(1995). Mice were maintained on a 12 h light/12 h dark cycle (light<br />
on between 0700 and 1900) at constant temperature (22°C), with<br />
food and water ad libitum . Animals were housed by groups of four<br />
and were habituated to their home cages for at least 1 week before<br />
the experiments. Mice were used only once and were treated in<br />
accordance with the Guide for Care and Use of Laboratory Animals<br />
established by the National Institutes of Health and with the<br />
European Community Council Directive 86/609/EEC.<br />
Rats Animals were Sprague–Dawley rats (Charles River<br />
Laboratories). After surgery, all animals were single-housed and<br />
maintained on a 12-h light/dark cycle (lights on at 0700) with food<br />
and water available ad libitum . Rats were allowed at least 3 days of<br />
postoperative recovery before any treatment began. All tests were<br />
performed during the light part of the light–dark cycle. All<br />
experimental procedures were performed in compliance with NIH<br />
Guide for Care and Use of Laboratory Animals (NIH No 85–23, rev.<br />
1985) and approved by the UCI Institutional Animal Care and Use<br />
Committee.<br />
Drugs<br />
(-)-Nicotine hydrogen tartrate, tranylcypromine hydrochloride,<br />
pargyline hydrochloride, R-(-)-deprenyl hydrochloride (selegiline),<br />
clorgyline, phenelzine sulfate were purchased from Sigma Aldrich<br />
(France). Moclobemide was from Roche Pharma (France). Drugs<br />
were dissolved in saline (NaCl, 0.9%) and the pH adjusted to 7.4
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 4/18<br />
with NaOH. Harmane and norharmane hydrochloride were from<br />
Sigma Aldrich (France). They were dissolved in distilled water with<br />
a few drops of 0.1 M lactic acid in order to get a pH>5. Doses are<br />
expressed as salts for all compounds except for nicotine which is<br />
expressed as base. Nicotine was injected subcutaneously<br />
(1.5 ml/kg per injection for mice) or intravenously (i.v.) (10 g/kg in<br />
20 l per injection for rats), whereas other treatments were injected<br />
intraperitoneally (i.p.) (3 ml/kg per injection).<br />
Measurement of Locomotor Activity<br />
Mice were introduced into a circular corridor (4.5 cm width, 17 cm<br />
external diameter) crossed by four infrared beams (1.5 cm above<br />
the base) placed at every 90° (Imetronic, Pessac, France).<br />
Locomotor activity was counted when animals interrupted two<br />
successive beams and thus had travelled a quarter of the circular<br />
corridor (1/4 turn). In each session, mice were placed in the<br />
locomotor apparatus for 90 min to record spontaneous activity<br />
before drug or vehicle treatment (MAOI or saline).<br />
To study the locomotor effects of various MAOIs, mice received an<br />
injection of MAOI and locomotor response was recorded during a<br />
subsequent 380-min. period. To study the effect of MAOI<br />
pretreatment on nicotine's locomotor effects, nicotine or saline were<br />
injected 100, 180, and 210 min following tranylcypromine,<br />
phenelzine, and clorgyline+selegiline administrations, respectively.<br />
These times were chosen because they corresponded to the delay<br />
from the time of injection to the onset of MAOI-induced locomotor<br />
effects. In the case of the other MAOIs, which did not elicit any<br />
locomotor effect, nicotine or saline was injected between 100 and<br />
210 min following MAOI administration. These injection times also<br />
marked the beginning of the 120-min period for measurement of the<br />
locomotor response to nicotine reported in Figure 2a and b. Tests<br />
were performed between 12:00 and 18:00 in stable conditions of<br />
temperature and humidity.<br />
Figure 2.<br />
Locomotor activity induced by nicotine in<br />
the presence of MAOIs: according to data<br />
shown in Figure 1b, nicotine or saline<br />
injections were performed 100, 210, and<br />
180 min following treatment injection for<br />
conditions 1, 2, and 3, respectively, and<br />
between 100 and 210 min following<br />
treatment injection for conditions 4–15.<br />
Diagrams a and b represent nicotine vs<br />
saline's effects on MAOI-induced locomotor<br />
effects. Locomotor response to<br />
MAOIs+saline (a) or ((MAOIs+nicotine)-<br />
(MAOIs+saline)) (b) was measured for<br />
120 min following saline or nicotine<br />
administration. * P
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wounds were closed with wound clips, antiseptic ointment was<br />
applied to the wounds, and Baytril (0.1 ml/150 g, i.m.) was injected<br />
to prevent infection. Antiseptic ointment was applied to the exposed<br />
cannula housing after each surgery to prevent infection, and a metal<br />
cap was attached to prevent damage to the cannula. The animals<br />
were kept in a warm cage for postsurgical observation until they<br />
emerged from anesthesia.<br />
The catheters were flushed daily with 0.2 ml sterile heparinized<br />
saline solution (0.3 ml of 1000 U/ml heparin in 30 ml saline) to<br />
maintain catheter patency. On test days, heparinized saline was<br />
injected before and after the self-administration session. After the<br />
final daily flush, the injection tubing was heat-sealed near the top of<br />
the cannula and left on in order to maintain a closed system and<br />
prevent clogging of the catheter in the home cage. The exposed<br />
cannula was protected by a threaded aluminum standoff. After the<br />
final daily test session, Propofol (0.6 ml/kg) was injected through<br />
the catheter to test the patency of the i.v. catheter as indicated by<br />
rapid (5–10 s) anesthesia. Data from all animals not demonstrating<br />
rapid anesthesia were discarded.<br />
Self-Administration<br />
Drug self-administration At 3–5 days after surgery, rats were<br />
tested in self-administration chambers with two nose-poke holes<br />
side-by-side in the door. A 10-ml syringe was mounted in an<br />
infusion pump, located outside the test chamber, and connected by<br />
polyethylene tubing to a feed-through swivel located above the test<br />
chamber. The other side of the feed-through swivel was connected<br />
to the infusion cannula on the animal's back with polyethylene<br />
tubing covered by a steel spring to prevent puncture from biting. The<br />
syringe was filled with enough solution to provide a maximum of<br />
200 injections. During each 1.1-s 20- l infusion, the signal light over<br />
the hole associated with drug injection went on for a 1.1-s period<br />
and, immediately after the drug infusion, responses were counted<br />
but had no effect for a 60-s period. All experimental parameters and<br />
data collection were controlled by a multichannel computer system<br />
(MED Associates, Inc., St Albans, VT).<br />
Acquisition of nicotine self-administration after a<br />
pretreatment with tranylcypromine A nose-poke response was<br />
used to measure drug self-administration. This response relies on<br />
the animals' natural olfactory exploration to provide adequate initial<br />
levels of responding. Priming at the start of each session was not<br />
employed because of possible aversive effects of non-contingent<br />
injections in naïve animals. A total of 27 rats were used in the<br />
experiment. Tests for acquisition of self-administration commenced<br />
without prior response training and consisted of five daily 3-h<br />
sessions with a fixed-ratio one (FR 1) reinforcement schedule.<br />
Each nose-poke at the reinforced hole (R) delivered nicotine (10<br />
g/kg/injection) or saline vehicle. To control for nonspecific activating<br />
effects of drugs, nonreinforced nose-pokes (NR) at a second<br />
adjacent hole were counted, but they had no programmed<br />
consequences. At 60 min before each session, rats received a<br />
pretreatment with tranylcypromine (3 mg/kg, i.p.) or saline vehicle<br />
(1 ml/kg, i.p.).<br />
Statistical Analysis of the Data<br />
Mice Results presented are means SEM of data obtained with 8<br />
–10 animals. Data were subjected to analysis of variance (ANOVA)<br />
using two-way ANOVA for MAOI treatment time (Figure 1b and<br />
comparison between Figure 3b and 3c), or for nicotine dose time<br />
(Figure 2a), three-way ANOVA for MAOI treatment nicotine dose<br />
time (Figure 3b and c) and genotype MAOI treatment time
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 6/18<br />
(comparison between Figures 3b and 4) with repeated measures on<br />
10 min intervals. Significant main effects or interactions were tested<br />
separately with ANOVAs and Bonferroni- or Dunnett's-corrected<br />
post hoc comparisons (Figures 1b, 2, 3 and 4). Time was<br />
considered as a within-subject factor and pharmacological<br />
treatments corresponded to independent groups of animals and<br />
were considered as between-subject factors. All data analyses<br />
were performed using GraphPad Prism 4.0 software (San Diego,<br />
CA) or SYSTAT 10 statistical software. Statistical significance was<br />
set at P
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 7/18<br />
Full figure and legend (25K)<br />
Rats For group differences over days, daily total 3-h self-injections<br />
for each group over the 5-day acquisition period were analyzed by<br />
three-way ANOVA for MAOI treatment nicotine dose day with<br />
repeated measures on day (Figure 5a). Daily reinforced (R) and<br />
nonreinforced (NR) scores were analyzed with a three-way ANOVA<br />
on nicotine dose reinforced/nonreinforced responses day with<br />
repeated measures on day. Significant main or interaction effects<br />
were further analyzed by one-way ANOVA for treatment for each<br />
day with Bonferroni- or Dunnett's-adjusted post hoc comparisons.<br />
Figure 5.<br />
RESULTS<br />
Effect of tranylcypromine on nicotine selfadministration:<br />
naïve animals were tested in<br />
daily 3-h self-administration sessions on an<br />
FR1 schedule. The mean ( SEM) total<br />
responses are plotted daily for each<br />
treatment group. (a) Reinforced responding<br />
for either nicotine (10 g/kg/injection) or<br />
saline, in rats pretreated with saline or<br />
tranylcypromine (3 mg/kg, i.p.). Rats<br />
pretreated with tranylcypromine and having<br />
access to i.v. injection of nicotine (10<br />
g/kg/injection) self-injected significantly<br />
more than rats pretreated with<br />
tranylcypromine having access to<br />
intravenous injection of saline or those<br />
pretreated with saline ** P
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Effects of Different Individual or Combined MAOIs on<br />
Nicotine-Induced Locomotor Activity<br />
Figure 2a shows locomotor activity following a saline injection in<br />
mice pretreated with MAOIs. Saline was injected at t=190, 270,<br />
300 min for tranylcypromine, phenelzine, clorgyline+selegiline, and<br />
between t=190 and t=300 for combinations 4–15, respectively. As<br />
previously explained in Material and Methods, these times were<br />
chosen because they corresponded to the onset of MAOI-induced<br />
locomotor effects. These times also corresponded to the start of<br />
the 120-min period used to assess the locomotor response scores<br />
shown in Figure 2a and b. Figure 2b summarizes the locomotor<br />
responses induced by nicotine under the same conditions. Data are<br />
presented as total activity obtained in presence of<br />
MAOI(s)+nicotine (1 mg/kg) minus the activity score obtained in the<br />
corresponding MAOI(s)+saline condition. Significant differences in<br />
locomotor responses between MAOI(s)+nicotine and<br />
MAOI(s)+saline occurred only for those MAOI treatment conditions<br />
that induced significant locomotor enhancement in the absence of<br />
nicotine (+69% t(1,14)=3.123 P
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 9/18<br />
interaction F(11,154)=6.067 P
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 10/18<br />
Mice and Trigger Nicotine-Induced Locomotor Response<br />
The data obtained with 15 individual or combined MAOIs indicate<br />
that only tranylcypromine, phenelzine, and the combination of<br />
clorgyline and selegiline induce locomotor activity. Tranylcypromine<br />
and phenelzine are irreversible mixed MAOIs, whereas clorgyline<br />
and selegiline are both irreversible and specific for MAO-A and -B,<br />
respectively. These findings indicate that only the irreversible<br />
blockade of both MAO-A and -B initiates a locomotor response in<br />
mice. Interestingly, this effect needs at least 80 min to develop,<br />
suggesting that an accumulation of extracellular monoamines is<br />
necessary for the effect to appear.<br />
Whereas each MAO isozyme exhibits some substrate specificity<br />
for noradrenaline, dopamine, or serotonin, there is sufficient overlap<br />
that both types of MAO must be inhibited to influence brain<br />
monoamine levels greatly (Shih, 2004). Thus, concomitant<br />
blockade of both MAO-A and -B may be necessary to induce<br />
locomotor activation. Furthermore, the finding that only irreversible<br />
MAOIs induce a locomotor response suggests that a sufficient<br />
accumulation of extracellular monoamines can only occur following<br />
sustained MAO inhibition. When nicotine was tested following<br />
MAOI pretreatment, the same three combinations of MAOI that<br />
induced locomotor activity also triggered a locomotor response to<br />
nicotine. This strongly suggests that the locomotor response to<br />
nicotine also necessitates an increase in the extracellular levels of<br />
monoamines, an increase that nicotine alone cannot sustain.<br />
Interestingly, when MAO activities in the brains of tobacco smokers<br />
were analyzed, both MAO-A and -B were found to be decreased<br />
(Fowler et al 1996a, 1996b).<br />
Further experiments performed in our laboratory have indicated that<br />
pretreatment with D-amphetamine which, as mentioned earlier, also<br />
stimulates locomotor activity but is 5000-fold less potent than<br />
tranylcypromine as a MAOI (Zirkle and Kaiser, 1964), does not<br />
induce any locomotor response to nicotine (AS Villégier et al,<br />
unpublished data). This indicates, first that the stimulatory<br />
locomotor effect of MAOIs cannot explain their induction of a<br />
locomotor response to nicotine and, second, that increases in<br />
extracellular levels of noradrenaline or dopamine (Darracq et al,<br />
1998) induced by D-amphetamine are not sufficient to produce a<br />
nicotine locomotor response. Indeed, microdialysis experiments<br />
have shown that it is specifically the facilitation of serotonergic<br />
transmission by MAOIs which is related to the increase in<br />
locomotor activity observed with nicotine (AS Villégier et al,<br />
unpublished data).<br />
It is interesting to note that harmane and norharmane, two MAOIs<br />
known to be present in tobacco (Poindexter and Carpenter, 1962),<br />
have no effect on nicotine locomotor response under our<br />
experimental conditions. This can be explained if one considers<br />
that they are both reversible MAOIs and block either MAO-A or -B<br />
(see Figure 1a). This suggests that, among the 3000 compounds<br />
contained in tobacco, harmane and norharmane probably do not<br />
contribute to the higher addictive effects of tobacco when compared<br />
with nicotine alone. Another MAOI, acetaldehyde, is very abundant<br />
in tobacco and tobacco smoke and was recently shown to enhance<br />
nicotine self-administration in adolescent rats (Lefèvre, 1989; Bates<br />
et al, 1999; Belluzzi et al, 2005). This compound may be a good<br />
candidate as a MAOI which facilitates the rewarding effects of<br />
tobacco.<br />
Why Does Nicotine Induce Locomotor Hyperactivity in Rats<br />
and not in Mice ?<br />
Although weak, nicotine exhibits a locomotor stimulant effect in<br />
rats and also, following repeated administration, behavioral<br />
sensitization (Vezina et al, 1994; Nisell et al, 1996; Villégier et al,
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 11/18<br />
2003). We show here that, in mice, MAOI pretreatment is<br />
necessary to obtain an acute locomotor response to nicotine. One<br />
reason for this difference could be that MAO activity differs between<br />
rats and mice.<br />
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a<br />
neurotoxin that induces a neurodegeneration of nigrostriatal<br />
dopaminergic neurons in mice and Parkinson's disease in man<br />
(Gerlach and Riederer, 1996). It has been shown that MPTP<br />
induces neurodegeneration through one of its toxic metabolites, 1methyl-4-phenylpyridine<br />
(MPP+). It is MAO-B which converts<br />
MPTP to MPP+ and the inhibition of MAO-B by deprenyl prevents<br />
the neurotoxic effects of MPTP (Heikkila et al, 1984; Langston et<br />
al, 1984; Fuller et al, 1988). Moreover, mice deficient in MAO-B do<br />
not sustain damage to striatal dopaminergic terminals after MPTP<br />
injection (Grimsby et al, 1997). Interestingly, rats have been<br />
reported to be at least partly resistant to the neurotoxic effects of<br />
MPTP (Mokry, 1995). This suggests that MAOs are less efficient in<br />
rats than in mice, thus allowing nicotine effects on monoamine<br />
extracellular levels, such as those on DA utilization or release<br />
(Tassin et al, 1992; Vezina et al, 1992; Di Chiara, 2000), to be<br />
maintained longer. MAO inhibition by irreversible MAOIs would<br />
induce a long-lasting increase in extracellular monoamines levels in<br />
mice.<br />
Implication of 2 nAChR in Locomotor Effects Induced by<br />
Nicotine<br />
To date, 12 neuronal nAChR subunits have been cloned in<br />
mammals, eight of which ( 3-7, 2-4) are expressed in rat<br />
dopaminergic neurons (Le Novere et al, 1996; Charpantier et al,<br />
1998; Klink et al, 2001; Champtiaux et al, 2002). Three main types<br />
of heteromeric nAChRs ( 4 2, 6 2, and 4 6 2) have been<br />
identified in dopaminergic terminal fields, whereas (non 6) 4 2<br />
nAChRs represent the majority of functional heteromeric nAChRs<br />
on dopaminergic neuronal somata and dendrites (Champtiaux et al,<br />
2003). Homomeric 7 and heteromeric 4 2 nAChRs, located in<br />
the ventral tegmental area (VTA) on glutamatergic and GABAergic<br />
neurons, respectively, have also been proposed to control the<br />
electrophysiological response of mesencephalic dopaminergic<br />
neurons to nicotine (Mansvelder and McGehee, 2000; Mansvelder<br />
et al, 2002).<br />
2-nAChR-KO mice exhibited an enhanced locomotor response to<br />
saline and tranylcypromine when compared with WT mice, thus<br />
confirming the hyper-reactivity to stress and drugs of abuse<br />
previously described in this strain (Villégier et al, 2004). However,<br />
nicotine-induced locomotor stimulation was not observed in 2nAChR-KO<br />
mice pretreated with tranylcypromine. This was not due<br />
to a ceiling effect. Although comparable locomotor responses were<br />
obtained with tranylcypromine (10 mg/kg) in 2-nAChR-KO mice<br />
and tranylcypromine (20 mg/kg) in WT mice, nicotine (1 mg/kg)<br />
only evoked locomotor activation in the WT mice pretreated with<br />
20 mg/kg tranylcypromine and not in 2-nAChR-KO mice.<br />
Moreover, nicotine induced a locomotor inhibition in 2-nAChR-KO<br />
mice pretreated with tranylcypromine. Altogether, this suggests that<br />
the nicotine-evoked locomotor response in WT animals pretreated<br />
with tranylcypromine is related to the stimulation of nAChRs<br />
containing the 2 subunit, such as the 4 2 nAChRs. The<br />
inhibition observed in 2-nAChR-KO mice may be due to a<br />
hyperdepolarization block of VTA-dopaminergic neurons caused by<br />
the glutamate released by the stimulation of the homomeric 7<br />
nAChRs located in the VTA (Mansvelder et al, 2002).<br />
Nicotine Self-Administration in Rats Pretreated with<br />
Tranylcypromine<br />
To determine whether our data obtained on locomotor responses to
http://www.nature.com/npp/journal/v31/n8/full/1300987a.html 12/18<br />
nicotine in mice may be related to an eventual rewarding effect of<br />
nicotine, we tested the effect of MAOI pretreatment on nicotine selfadministration<br />
in rats. As previously described, nicotine selfadministration<br />
is weaker than for other drugs of abuse and often<br />
needs facilitation by the use of food restriction or cocaine<br />
pretreatment. Since our experiments did not include any of these<br />
conditions, nicotine was not self-administered in saline-pretreated<br />
rats, as has been shown previously (Belluzzi et al, 2005). However,<br />
when pretreated with tranylcypromine, rats exhibited a robust selfadministration,<br />
strongly suggesting that MAOIs facilitate the effects<br />
of nicotine on the reward system. Tranylcypromine also increased<br />
the global activity of the animals as seen by increased saline selfinjections.<br />
However, the significant difference observed between the<br />
reinforced and the nonreinforced hole indicates that MAOIs<br />
specifically stimulate nicotine-seeking behaviour.<br />
CONCLUSION<br />
Top<br />
Pretreatment of mice with irreversible and mixed MAOI(s) facilitates<br />
nicotine-induced locomotor activation. The absence of a locomotor<br />
response to nicotine in 2-nAChR-KO mice confirms the<br />
involvement of nAChRs containing 2 subunits in the locomotor<br />
effects observed in the presence of MAOIs in WT mice. Finally, the<br />
facilitation of nicotine self-administration by MAOI pretreatment<br />
strongly indicates that the MAOIs present in tobacco and tobacco<br />
smoke act in synergy with nicotine to induce addiction. The<br />
utilization of MAOIs in experimental models of reward may<br />
therefore provide a more complete scheme of the addictive<br />
properties of tobacco.<br />
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Acknowledgements<br />
This work was supported by a fellowship from Fondation Gilbert<br />
Lagrue and by PHS Grant DA13332. We thank Luis Stinus for his<br />
advice on self-administration conditions.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
49 Uncoupling between noradrenergic and sero-<br />
tonergic neurons as a molecular basis of stable<br />
changes in behavior induced by repeated drugs<br />
of abuse.
http://www.ncbi.nlm.nih.gov/pubmed/17686465 1/2<br />
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Biochem Pharmacol. 2008 Jan 1;75(1):85-97. Epub 2007 Jun 30.<br />
Uncoupling between noradrenergic and serotonergic neurons as a<br />
molecular basis of stable changes in behavior induced by repeated drugs<br />
of abuse.<br />
Tassin JP.<br />
PubMed<br />
Institut National de la Santé et de la Recherche Médicale Unité 114, Centre National de la Recherche Scientifique UMR<br />
7148, Collège de France 11, Place Marcelin Berthelot, 75231 Paris Cedex 05, France. jean-pol.tassin@college-defrance.fr<br />
Abstract<br />
A challenge in drug dependence is to delineate long-term behavioral and neurochemical<br />
modifications induced by drugs of abuse. In rodents, drugs of abuse induce locomotor hyperactivity,<br />
and repeating injections enhance this response. This effect, called behavioral sensitization, persists<br />
many months after the last administration, thus mimicking long-term sensitivity to drugs observed in<br />
human addicts. Although addictive properties of drugs of abuse are generally considered to be<br />
mediated by an increased release of dopamine in the ventral striatum, recent pharmacological and<br />
PMID: 17686465 [PubMed - indexed for MEDLINE]<br />
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Behavioral sensitization to<br />
[Proc amphetamine Natl Acad results Sci U from S A. an 2006]<br />
Drugs of abuse specifically<br />
[Neuropsychopharmacology. sensitize noradrenergic and2008]<br />
Alpha1b-adrenergic receptors<br />
control locomotor [J Neurosci. and rewarding 2002]<br />
Review [Involvement of prefrontal<br />
genetic experiments indicate an implication of alpha1b-adrenergic receptors in behavioral [Nihon andShinkei<br />
serotonergic Seishin Yakurigaku neurons Zasshi. in 20...]<br />
rewarding responses to psychostimulants and opiates. Later on, it was shown that not only<br />
Review Neuropsychotoxicity of<br />
noradrenergic but also serotonergic systems, through 5-HT(2A) receptors, were controlling abused drugs: [J Pharmacol effects of Sci. 2008]<br />
behavioral effects of drugs of abuse. More recently, experiments performed in animals knockout for<br />
alpha1b-adrenergic or 5-HT(2A) receptors indicated that noradrenergic and serotonergic neurons,<br />
See reviews...<br />
besides their activating effects, inhibit each other by means of the stimulation of alpha1b-adrenergic<br />
See all...<br />
and 5-HT(2A) receptors and that this mutual inhibition vanishes in wild type mice with repeated<br />
injections of psychostimulants, opiates or alcohol. Uncoupling induced by repeated treatments with<br />
drugs of abuse installs a stable sensitization of noradrenergic and serotonergic neurons, thus Cited by 6 PubMed<br />
explaining an increased reactivity of dopaminergic neurons and behavioral sensitization. We Central articles<br />
propose that noradrenergic/serotonergic uncoupling is a common stable neurochemical<br />
Biogenic amines and their<br />
consequence of repeated drugs of abuse which may also occur during chronic stressful situations metabolites [BMC are differentially Neurosci. 2011]<br />
and facilitate the onset of mental illness. Drug consumption would facilitate an artificial re-coupling<br />
Nicotine alters limbic function in<br />
of these neurons, thus bringing a temporary relief.<br />
[Neuropsychopharmacology. adolescent rat by a 5-HT1A 2011]<br />
Abnormal cortical responses to<br />
somatosensory [BMC stimulation Neurol. 2010] in<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
50 Acute effects of using an electronic nicotine-<br />
delivery device (e-cigarette) on myocardial func-<br />
tion comparison with the effects of regular ciga-<br />
rettes.
Nachschlagewerk zum Thema E-Zigaretten<br />
51 Metabolism and Disposition Kinetics of Nicotine.
http://pharmrev.aspetjournals.org/content/57/1/79.abstract 1/7<br />
HOME CURRENT ISSUE ARCHIVE FEEDBACK SUBSCRIPTIONS ALERTS HELP<br />
Metabolism and Disposition Kinetics of Nicotine<br />
Janne Hukkanen, Pleyton Jacob III and Neal L. Benowitz<br />
+ Author Affiliations<br />
Address correspondence to: Dr. Neal L. Benowitz, Division of Clinical Pharmacology and<br />
Experimental Therapeutics, University of California, San Francisco, Box 1220, San<br />
Francisco, CA 94143-1220. E-mail: nbeno@itsa.ucsf.edu<br />
Abstract<br />
Nicotine is of importance as the addictive chemical in tobacco, pharmacotherapy for<br />
smoking cessation, a potential medication for several diseases, and a useful probe drug<br />
for phenotyping cytochrome P450 2A6 (CYP2A6). We review current knowledge about the<br />
metabolism and disposition kinetics of nicotine, some other naturally occurring tobacco<br />
alkaloids, and nicotine analogs that are under development as potential therapeutic<br />
agents. The focus is on studies in humans, but animal data are mentioned when relevant<br />
to the interpretation of human data. The pathways of nicotine metabolism are described in<br />
detail. Absorption, distribution, metabolism, and excretion of nicotine and related<br />
compounds are reviewed. Enzymes involved in nicotine metabolism including cytochrome<br />
P450 enzymes, aldehyde oxidase, flavin-containing monooxygenase 3, amine N-<br />
methyltransferase, and UDP-glucuronosyltransferases are represented, as well as factors<br />
affecting metabolism, such as genetic variations in metabolic enzymes, effects of diet,<br />
age, gender, pregnancy, liver and kidney diseases, and racial and ethnic differences. Also<br />
effects of smoking and various inhibitors and inducers, including oral contraceptives, on<br />
nicotine metabolism are discussed. Due to the significance of the CYP2A6 enzyme in<br />
nicotine clearance, special emphasis is given to the effects and population distributions of<br />
CYP2A6 alleles and the regulation of CYP2A6 enzyme.<br />
Footnotes<br />
↵1 Abbreviations: NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; NNAL, 4-<br />
(methylnitrosamino)-1-(3-pyridyl)-1-butanol; NRT, nicotine replacement therapy; FMO,<br />
flavin-containing monooxygenase; UGT, uridine diphosphate-glucuronosyltransferase;<br />
P450, cytochrome P450; PXR, pregnane X receptor; CAR, constitutive androstane<br />
receptor; OCTN1, organic cation transporter number 1; ABT-418, (S)-3-methyl-5-(1-<br />
methyl-2-pyrrolidinyl) isoxazole hydrochloride; ABT-089, 2-methyl-3-(2-(S)-<br />
pyrrolidinylmethoxy) pyridine dihydrochloride; ABT-594, (R)-5-(2-azetidinylmethoxy)-2-<br />
chloropyridine; SIB-1765F, [±]-5-ethynyl-3-(1-methyl-2-pyrrolidinyl) pyridine fumarate;<br />
SIB-1508Y, [S]-[-]-5-ethynyl-3-(1-methyl-2-pyrrolidinyl) pyridine maleate; RJR-2403,<br />
(E)-N-methyl-4-(3-pyridinyl)-3-butene-1-amine; GTS-21 or DMXB, 3′-(2,4-<br />
dimethoxybenzylidine)-anabaseine; SIB-1663, [±]-7-methoxy-2,3,3a,4,5,9b-<br />
hexahydro-1H-pyrrolo-[3,2h]-isoquinoline; A-85380, 3-[2(S)-2-azetidinyl-<br />
methoxy]pyridine.<br />
Article, publication date, and citation information can be found at<br />
http://pharmrev.aspetjournals.org.<br />
doi:10.1124/pr.57.1.3.<br />
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Smokers<br />
Nicotine Tob Res August 1, 2011 13:686-690<br />
Abstract Full Text Full Text (PDF)<br />
Effect of Mint Drink on Metabolism of Nicotine as Measured by Nicotine<br />
to Cotinine Ratio in Urine of Jordanian Smoking Volunteers<br />
Nicotine Tob Res August 1, 2011 13:661-667<br />
Abstract Full Text Full Text (PDF)<br />
Human Theta Burst Stimulation Enhances Subsequent Motor Learning<br />
and Increases Performance Variability<br />
Cereb Cortex July 1, 2011 21:1627-1638<br />
Abstract Full Text Full Text (PDF)
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Chronic nicotine exposure exacerbates acute renal ischemic injury<br />
Am. J. Physiol. Renal Physiol. July 1, 2011 301:F125-F133<br />
Abstract Full Text Full Text (PDF)<br />
Association of the Nicotine Metabolite Ratio and CHRNA5/CHRNA3<br />
Polymorphisms With Smoking Rate Among Treatment-Seeking Smokers<br />
Nicotine Tob Res June 1, 2011 13:498-503<br />
Abstract Full Text Full Text (PDF)<br />
Menthol's potential effects on nicotine dependence: a tobacco industry<br />
perspective<br />
Tobacco Control May 1, 2011 20:ii29-ii36<br />
Abstract Full Text Full Text (PDF)<br />
Electrophysiological evidence of nicotine's distracter-filtering properties<br />
in non-smokers<br />
J Psychopharmacol February 1, 2011 25:239-248<br />
Abstract Full Text Full Text (PDF)<br />
High-Throughput Simultaneous Analysis of Five Urinary Metabolites of<br />
Areca Nut and Tobacco Alkaloids by Isotope-Dilution Liquid<br />
Chromatography-Tandem Mass Spectrometry with On-Line Solid-Phase<br />
Extraction<br />
Cancer Epidemiol. Biomarkers Prev. October 1, 2010 19:2570-2581<br />
Abstract Full Text Full Text (PDF)<br />
Glucuronidation Genotypes and Nicotine Metabolic Phenotypes:<br />
Importance of Functional UGT2B10 and UGT2B17 Polymorphisms<br />
Cancer Res. October 1, 2010 70:7543-7552<br />
Abstract Full Text Full Text (PDF)<br />
Carbamazepine but Not Valproate Induces CYP2A6 Activity in Smokers<br />
with Mental Illness<br />
Cancer Epidemiol. Biomarkers Prev. October 1, 2010 19:2582-2589<br />
Abstract Full Text Full Text (PDF)<br />
Repetitive Nicotine Exposure Leads to a More Malignant and Metastasis-<br />
Prone Phenotype of SCLC: A Molecular Insight into the Importance of<br />
Quitting Smoking during Treatment<br />
Toxicol Sci August 1, 2010 116:467-476<br />
Abstract Full Text Full Text (PDF)<br />
UGT2B10 Genotype Influences Nicotine Glucuronidation, Oxidation, and<br />
Consumption<br />
Cancer Epidemiol. Biomarkers Prev. June 1, 2010 19:1423-1431<br />
Abstract Full Text Full Text (PDF)<br />
Biomarker evaluation of Greek adolescents' exposure to secondhand<br />
smoke<br />
Hum Exp Toxicol June 1, 2010 29:459-466<br />
Abstract Full Text (PDF)<br />
Estimation of Nicotine Dose after Low-level Exposure Using Plasma and<br />
Urine Nicotine Metabolites<br />
Cancer Epidemiol. Biomarkers Prev. May 1, 2010 19:1160-1166<br />
Abstract Full Text Full Text (PDF)<br />
Nicotine and its metabolites in amniotic fluid at birth - Assessment of<br />
prenatal tobacco smoke exposure<br />
Hum Exp Toxicol May 1, 2010 29:385-391<br />
Abstract Full Text (PDF)<br />
Effect of an electronic nicotine delivery device (e cigarette) on desire to<br />
smoke and withdrawal, user preferences and nicotine delivery:<br />
randomised cross-over trial<br />
Tobacco Control April 1, 2010 19:98-103<br />
Abstract Full Text Full Text (PDF)<br />
From the Cover: Kinetics of brain nicotine accumulation in dependent
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and nondependent smokers assessed with PET and cigarettes containing<br />
11C-nicotine<br />
Proc. Natl. Acad. Sci. USA March 16, 2010 107:5190-5195<br />
Abstract Full Text Full Text (PDF)<br />
Role of CYP2A5 in the Clearance of Nicotine and Cotinine: Insights from<br />
Studies on a Cyp2a5-null Mouse Model<br />
J. Pharmacol. Exp. Ther. February 1, 2010 332:578-587<br />
Abstract Full Text Full Text (PDF)<br />
Nicotine Exacerbates Brain Edema during In Vitro and In Vivo Focal<br />
Ischemic Conditions<br />
J. Pharmacol. Exp. Ther. February 1, 2010 332:371-379<br />
Abstract Full Text Full Text (PDF)<br />
Nicotine Metabolism in African Americans and European Americans:<br />
Variation in Glucuronidation by Ethnicity and UGT2B10 Haplotype<br />
J. Pharmacol. Exp. Ther. January 1, 2010 332:202-209<br />
Abstract Full Text Full Text (PDF)<br />
Utility and Relationships of Biomarkers of Smoking in African-American<br />
Light Smokers<br />
Cancer Epidemiol. Biomarkers Prev. December 1, 2009 18:3426-3434<br />
Abstract Full Text Full Text (PDF)<br />
Assessment of Smoking Behaviors and Alcohol Use in the National<br />
Social Life, Health, and Aging Project<br />
J Gerontol B Psychol Sci Soc Sci November 1, 2009 64B:i119-i130<br />
Abstract Full Text Full Text (PDF)<br />
Presence of the Carcinogen N'-Nitrosonornicotine in the Urine of Some<br />
Users of Oral Nicotine Replacement Therapy Products<br />
Cancer Res. November 1, 2009 69:8236-8240<br />
Abstract Full Text Full Text (PDF)<br />
Association of serum cotinine level with a cluster of three nicotinic<br />
acetylcholine receptor genes (CHRNA3/CHRNA5/CHRNB4) on<br />
chromosome 15<br />
Hum Mol Genet October 15, 2009 18:4007-4012<br />
Abstract Full Text Full Text (PDF)<br />
Prediction of Birth Weight By Cotinine Levels During Pregnancy in a<br />
Population of Black Smokers<br />
Pediatrics October 1, 2009 124:e671-e680<br />
Abstract Full Text Full Text (PDF)<br />
Characterization of a Nicotine-Sensitive Neuronal Population in Rat<br />
Entorhinal Cortex<br />
J. Neurosci. August 19, 2009 29:10436-10448<br />
Abstract Full Text Full Text (PDF)<br />
Urine nicotine metabolite concentrations in relation to plasma cotinine<br />
during low-level nicotine exposure<br />
Nicotine Tob Res August 1, 2009 11:954-960<br />
Abstract Full Text Full Text (PDF)<br />
Association of cotinine levels and preeclampsia among African-<br />
American women<br />
Nicotine Tob Res June 1, 2009 11:679-684<br />
Abstract Full Text Full Text (PDF)<br />
Effects of acute nicotine on event-related potential and performance<br />
indices of auditory distraction in nonsmokers<br />
Nicotine Tob Res May 1, 2009 11:519-530<br />
Abstract Full Text Full Text (PDF)<br />
A pilot study of nicotine delivery to smokers from a metered-dose<br />
inhaler<br />
Nicotine Tob Res April 3, 2009 0:ntp027v1-ntp027<br />
Abstract Full Text Full Text (PDF)
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Evidence for endogenous formation of N'-nitrosonornicotine in some<br />
long-term nicotine patch users<br />
Nicotine Tob Res January 27, 2009 0:ntn004v1-ntn004<br />
Abstract Full Text Full Text (PDF)<br />
Correlation between the Urine Profile of 4-(Methylnitrosamino)-1-(3-<br />
Pyridyl)-1-Butanone Metabolites and N7-Methylguanine in Urothelial<br />
Carcinoma Patients<br />
Cancer Epidemiol. Biomarkers Prev. December 1, 2008 17:3390-3395<br />
Abstract Full Text Full Text (PDF)<br />
Nicotine Intake in Cigarette Smokers in England: Distribution and<br />
Demographic Correlates<br />
Cancer Epidemiol. Biomarkers Prev. December 1, 2008 17:3331-3336<br />
Abstract Full Text Full Text (PDF)<br />
Nicotine Metabolism in Three Ethnic/Racial Groups with Different Risks<br />
of Lung Cancer<br />
Cancer Epidemiol. Biomarkers Prev. December 1, 2008 17:3526-3535<br />
Abstract Full Text Full Text (PDF)<br />
Continuous and Intermittent Nicotine Treatment Reduces L-3,4-<br />
Dihydroxyphenylalanine (L-DOPA)-Induced Dyskinesias in a Rat Model of<br />
Parkinson's Disease<br />
J. Pharmacol. Exp. Ther. October 1, 2008 327:239-247<br />
Abstract Full Text Full Text (PDF)<br />
Review: Pharmacotherapy for smoking cessation<br />
Ther Adv Respir Dis October 1, 2008 2:301-317<br />
Abstract Full Text (PDF)<br />
Nicotine and Postoperative Management of Pain<br />
Anesth. Analg. September 1, 2008 107:739-741<br />
Full Text Full Text (PDF)<br />
Cotinine Selectively Activates a Subpopulation of<br />
{alpha}3/{alpha}6{beta}2 Nicotinic Receptors in Monkey Striatum<br />
J. Pharmacol. Exp. Ther. May 1, 2008 325:646-654<br />
Abstract Full Text Full Text (PDF)<br />
Evidence for Carbon Monoxide as the Major Factor Contributing to<br />
Lower Fetal Weights in Rats Exposed to Cigarette Smoke<br />
Toxicol Sci April 1, 2008 102:383-391<br />
Abstract Full Text Full Text (PDF)<br />
Measuring Secondhand Smoke Exposure in Children: An Ecological<br />
Measurement Approach<br />
J Pediatr Psychol March 1, 2008 33:156-175<br />
Abstract Full Text Full Text (PDF)<br />
Microsomal epoxide hydrolase, glutathione S-transferase P1, traffic and<br />
childhood asthma<br />
Thorax December 1, 2007 62:1050-1057<br />
Abstract Full Text Full Text (PDF)<br />
123I-5-IA-85380 SPECT Imaging of Nicotinic Acetylcholine Receptor<br />
Availability in Nonsmokers: Effects of Sex and Menstrual Phase<br />
JNM October 1, 2007 48:1633-1640<br />
Abstract Full Text Full Text (PDF)<br />
Glucuronidation of Nicotine and Cotinine by UGT2B10: Loss of Function<br />
by the UGT2B10 Codon 67 (Asp>Tyr) Polymorphism<br />
Cancer Res. October 1, 2007 67:9024-9029<br />
Abstract Full Text Full Text (PDF)<br />
Drug interactions with smoking<br />
Am J Health Syst Pharm September 15, 2007 64:1917-1921<br />
Abstract Full Text Full Text (PDF)
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Nicotine Glucuronidation and the Human UDP-Glucuronosyltransferase<br />
UGT2B10<br />
Mol. Pharmacol. September 1, 2007 72:761-768<br />
Abstract Full Text Full Text (PDF)<br />
Relationship of Human Toenail Nicotine, Cotinine, and 4-<br />
(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol to Levels of These<br />
Biomarkers in Plasma and Urine<br />
Cancer Epidemiol. Biomarkers Prev. July 1, 2007 16:1382-1386<br />
Abstract Full Text Full Text (PDF)<br />
Urinary cotinine as an objective measure of cigarette smoking in chronic<br />
kidney disease<br />
Nephrol Dial Transplant July 1, 2007 22:1950-1954<br />
Abstract Full Text Full Text (PDF)<br />
State of the Art Reviews: Smoking Cessation: A Review of Treatment<br />
Considerations<br />
AMERICAN JOURNAL OF LIFESTYLE MEDICINE May 1, 2007 1:201-213<br />
Abstract Full Text (PDF)<br />
A two-component small multidrug resistance pump functions as a<br />
metabolic valve during nicotine catabolism by Arthrobacter<br />
nicotinovorans<br />
Microbiology May 1, 2007 153:1546-1555<br />
Abstract Full Text Full Text (PDF)<br />
Characterization and Comparison of Nicotine and Cotinine Metabolism<br />
in Vitro and in Vivo in DBA/2 and C57BL/6 Mice<br />
Mol. Pharmacol. March 1, 2007 71:826-834<br />
Abstract Full Text Full Text (PDF)<br />
Mass Spectrometric Quantitation of Nicotine, Cotinine, and 4-<br />
(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol in Human Toenails<br />
Cancer Epidemiol. Biomarkers Prev. December 1, 2006 15:2378-2383<br />
Abstract Full Text Full Text (PDF)<br />
Multiple-dose pharmacokinetics of the selective nicotinic receptor<br />
partial agonist, varenicline, in healthy smokers.<br />
J Clin Pharmacol December 1, 2006 46:1439-1448<br />
Abstract Full Text Full Text (PDF)<br />
Degradative transport of cationic amphiphilic drugs across phospholipid<br />
bilayers<br />
Phil Trans R Soc A October 15, 2006 364:2597-2614<br />
Abstract Full Text Full Text (PDF)<br />
Copyright © 2013 by the American Society for Pharmacology and Experimental Therapeutics<br />
ISSN 1521-0081 (Online)
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52 Electronic Cigarettes As a Smoking-Cessation<br />
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Volume 52, Issue 2 , Pages 144-150, February 2013<br />
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Adolescent Males' Awareness of and Willingness to Try Electronic<br />
Cigarettes<br />
Jessica K. Pepper, M.P.H., Paul L. Reiter, Ph.D., Annie-Laurie McRee, Dr.P.H., Linda D. Cameron, Ph.D., Melissa B. Gilkey, Ph.D., Noel T. Brew er,<br />
Ph.D.<br />
Received 19 June 2012; accepted 19 September 2012. published online 30 November 2012.<br />
Abstract Full Text PDF References<br />
Article Outline<br />
I. Abstract<br />
II. Methods<br />
A. Participants<br />
B. Measures<br />
C. Data analyses<br />
III. Results<br />
A. Participants<br />
B. Use of e-cigarettes<br />
C. Aw areness of e-cigarettes<br />
D. Willingness to try e-cigarettes<br />
IV. Discussion<br />
V. References<br />
VI. Copyright<br />
Abstract<br />
Purpose<br />
Electronic cigarettes (e-cigarettes) are a new type of device that delivers vaporized nicotine without the tobacco combustion<br />
of regular cigarettes. We sought to understand awareness of and willingness to try e-cigarettes among adolescent males, a<br />
group that is at risk for smoking initiation and may use e-cigarettes as a “gateway” to smoking.<br />
Methods<br />
A national sample of 11–19-year-old males ( n = 228) completed an online survey in November 2011. We recruited<br />
participants through their parents, who were members of a panel of U.S. households constructed using random-digit dialing<br />
and addressed-based sampling.<br />
Results<br />
Only two participants (< 1%) had previously tried e-cigarettes. Among those who had not tried e-cigarettes, most (67%) had<br />
heard of them. Awareness was higher among older and non-Hispanic adolescents. Nearly 1 in 5 (18%) participants were<br />
willing to try either a plain or flavored e-cigarette, but willingness to try plain versus flavored varieties did not differ. Smokers<br />
were more willing to try any e-cigarette than nonsmokers (74% vs. 13%; OR 10.25, 95% CI 2.88, 36.46). Nonsmokers who<br />
had more negative beliefs about the typical smoker were less willing to try e-cigarettes (OR .58, 95% CI .43, .79).<br />
Conclusions<br />
Most adolescent males were aware of e-cigarettes, and a substantial minority were willing to try them. Given that even<br />
experimentation with e-cigarettes could lead to nicotine dependence and subsequent use of other tobacco products,<br />
regulatory and behavioral interventions are needed to prevent “gateway” use by adolescent nonsmokers. Campaigns<br />
promoting negative images of smokers or FDA bans on sales to youth may help deter use.<br />
Keyw ords: Electronic cigarette , Adolescents , Males , Nicotine , Smoking , Aw areness<br />
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Electronic cigarettes (e-cigarettes) are battery-operated devices that are typically made to look and perform like regular<br />
cigarettes. They contain an inhalation-activated mechanism that heats liquid from a cartridge composed of humectants and<br />
nicotine, although non-nicotine e-cigarettes are also available. Users, sometimes called “vapers,” inhale the resulting vapor.<br />
Safety data on e-cigarettes are sparse and inconsistent [1], [2], giving rise to considerable concern about the lack of quality<br />
control in manufacturing [3]. The U.S. Food and Drug Administration (FDA) is working to regulate e-cigarettes as tobacco<br />
products [4], but regulations are not yet in place.<br />
While fewer than 3% of American adults had used e-cigarettes as of 2010 [5], public interest is skyrocketing [6], and the<br />
popular media (e.g., New York Times; Parade Magazine) has covered them extensively [7], [8]. Existing research suggests<br />
that smokers are more likely than nonsmokers to try e-cigarettes [5]. The most frequently cited reason for use among<br />
“vapers” is to help them quit smoking or reduce use of traditional cigarettes [9], [10], [11]. Given the unknown long-term<br />
consequences of e-cigarette use and the lack of comprehensive data on product safety or utility as a cessation aid, the<br />
public health and tobacco control communities are both strongly divided about whether e-cigarettes are dangerous or a<br />
promising harm reduction strategy for adult smokers [12], [13], [14], [15].<br />
Tobacco control advocates and researchers are also concerned that e-cigarettes could act as “gateway” devices, getting<br />
novice users, particularly young people, addicted to nicotine and encouraging future tobacco use [15]. Given that most<br />
tobacco use begins during adolescence and males are more likely than females to use tobacco products [16], we sought to<br />
understand how male adolescents respond to e-cigarettes. Because earlier beliefs about a “typical smoker” are related to<br />
future use of cigarettes by adolescents [17], we also wished to explore how social images of smokers might influence<br />
willingness to try a cigarette-like product. No published studies we are aware of have examined U.S. adolescent males'<br />
views about e-cigarettes. We surveyed a national sample of males ages 11–19 to explore their awareness of e-cigarettes<br />
and their willingness to try them.<br />
Back to Article Outline<br />
Methods<br />
Participants<br />
Parents and their adolescent sons participated in an online, two-wave survey on adolescent health described in detail by<br />
Reiter et al [18]. In brief, a survey company constructed a national panel of U.S. households by using probability sampling, a<br />
combination of list-assisted, random-digit dialing and address-based sampling to reach cell phone-only households [19].<br />
The survey company then randomly sampled panel members who were parents with sons ages 11–17 years. In August and<br />
September 2010, parents and sons completed the online Wave 1 survey. We re-contacted these parents and sons in<br />
November 2011 to participate in the present survey (i.e., Wave 2). Four parents indicated that their sons were 11 years old at<br />
Wave 2, suggesting that the son's age documented in the panel profile or Wave 2 survey was off by a year. In exchange for<br />
participation, parents received 1,000 points (worth about $1) that they could later redeem for small cash payments.<br />
Households without Internet access received laptops and free Internet access. Sons received 10,000 points (worth about<br />
$10) for completing the Wave 2 survey. The Institutional Review Board at the University of North Carolina approved the study.<br />
The survey company sent e-mail invitations to participate in the study to 421 parents who participated in the Wave 1 survey.<br />
Three reminder e-mails were sent to parents between Waves 1 and 2 to maximize participation at Wave 2. Only the Wave 2<br />
survey included items about e-cigarettes. Of the 327 parents (78%) who completed the Wave 2 surveys, 228 (70%) had<br />
adolescent sons who also completed surveys. There were no differences between the 70% of sons who completed Wave 2<br />
surveys and the 30% who did not in terms of: son's race or ethnicity; parent's age, gender, marital status, or smoking status;<br />
or the household's income, urbanicity, or region. Sons who completed the Wave 2 survey were less likely to have parents<br />
who attended at least some college than sons who did not complete the Wave 2 survey (56% vs. 69%, p = .04).<br />
Measures<br />
Sons' Wave 2 surveys assessed awareness of e-cigarettes by asking “Have you ever heard of electronic cigarettes, often<br />
called e-cigarettes?” (0 = no, 1 = yes). All sons then viewed a brief informational statement about e-cigarettes: “E-cigarettes<br />
look like regular cigarettes but they are different. They create a mist that you breathe in like smoke, but they are not made of<br />
tobacco.” We then asked “Have you ever seen someone using an e-cigarette?” (0 = no, 1 = yes) and “Have you ever used an<br />
e-cigarette?” (0 = no, 1 = yes).<br />
Because e-cigarettes are available in a variety of flavors (plain as well as candy- or fruit-flavored), we assessed willingness<br />
to use an e-cigarette with two items: “If one of your best friends were to offer you an e-cigarette, would you try it?” and “If one<br />
of your best friends were to offer you a flavored e-cigarette (chocolate, mint, apple, etc.), would you try it?” Responses of<br />
“definitely not” or “probably not” were coded as 0, and responses of “definitely yes” or “probably yes” were coded as 1. For<br />
some analyses, we grouped responses of willingness to try plain and flavored e-cigarettes to create a variable for<br />
willingness to try any kind of e-cigarette (0 = no, 1 = yes), such that ‘1’ included respondents who were willing to try plain but<br />
not flavored e-cigarettes, flavored but not plain e-cigarettes, or both kinds of e-cigarettes.<br />
We classified adolescent participants as nonsmokers (coded as 0) if they responded “never, I am not a smoker” to the<br />
question “How often do you smoke now?” We classified all other responses (“less than once a month,” “at least once a<br />
month,” “at least once a week,” and “at least once a day”) as indicating smokers (coded as 1). The item “Do you think you will<br />
smoke a cigarette in the next year?” assessed participants' susceptibility to cigarette use. We coded responses of “definitely<br />
not” or “probably not” as 0 and responses of “definitely yes” or “probably yes” as 1.<br />
As described by the prototype/willingness model, adolescents' willingness to engage in risky behaviors like smoking is<br />
influenced by their self-comparisons to a social image (or prototype) of the kind of person who engages in that behavior [20].<br />
Thus, prior to asking participants about their awareness and use of e-cigarettes, we evaluated their smoker prototypes [21],<br />
[22]. We instructed them to “Consider a typical person your age who smokes. How would you describe this person using the<br />
following characteristics?” For each of a set of eight adjectives, displayed in a random order, participants responded on a 5point<br />
scale from “not at all” (coded as 1) to “very much” (5). We created a mean score (range 1–5) for the four items that<br />
assessed positive smoker prototypes (stylish, tough, cool, and independent; alpha = .79), and a mean score for the four<br />
items that assessed negative smoker prototypes (unattractive, immature, inconsiderate, and trashy; alpha = .85).<br />
Demographic characteristics included sons' age, ethnicity (Hispanic/Latino or not Hispanic/Latino), and race (white or nonwhite),<br />
as well as parents' marital status, education, and smoking habits. We classified parents as having “never or rarely<br />
smoked” (smoked less than 100 cigarettes in their lifetimes), being “former smokers” (smoked more than 100 cigarettes in
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their lifetimes but not current smokers), or being “current smokers” (smoke cigarettes some days or every day). We also<br />
collected data on household characteristics: income, urbanicity (as described by the Census Bureau definition of<br />
metropolitan statistical areas, http://factfinder.census.gov/home/en/epss/glossary_r.html), and region of residence<br />
(Northeast, Midwest, South, and West). All demographic characteristics (except son's age and son's smoking status) used<br />
data collected at Wave 1. The complete parent and son surveys are available online at<br />
http://www.unc.edu/∼ntbrewer/hpv.htm.<br />
Data analyses<br />
Among sons without past use of e-cigarettes, we examined bivariate correlates of awareness of and willingness to try any<br />
kind of e-cigarette (plain, flavored, or both) using logistic regression. All correlates identified as statistically significant<br />
(p < .05) in bivariate analyses were included in a multivariate model. For willingness to try e-cigarettes, we repeated the<br />
multivariate analysis restricted to nonsmokers. We analyzed data with SPSS version 17.0 (SPSS Inc., Chicago, IL). Statistical<br />
tests were two-tailed with a critical alpha of .05.<br />
Back to Article Outline<br />
Results<br />
Participants<br />
Adolescents' mean age was 15.1 years (Table 1 ). Most were nonsmokers (91%), white (80%), and lived in urban areas<br />
(84%). About half of parents reported a household income of less than $60,000 (48%). Most parents had never or rarely<br />
smoked (43%) or were former smokers (41%).<br />
Table 1. Demographic characteristics (n = 228)<br />
Adolescent males<br />
n (%)<br />
Age, mean (SD) 15.1 (2.1)<br />
Race<br />
Parent<br />
White 182 (80)<br />
Non-w hite 46 (20)<br />
Ethnicity<br />
Hispanic/Latino 38 (17)<br />
Non-Hispanic/Latino 190 (83)<br />
Smoking status<br />
Nonsmoker 207 (91)<br />
Smoker 21 (9)<br />
Positive smoker prototype, mean (SD) a 1.7 (.8)<br />
Negative smoker prototype, mean (SD) b 3.2 (1.1)<br />
Will smoke in the next year<br />
No 208 (91)<br />
Yes 20 (9)<br />
Tried an e-cigarette<br />
Age<br />
No 226 (99)<br />
Yes 2 (1)<br />
< 45 years 140 (61)<br />
≥ 45 years 88 (39)<br />
Gender<br />
Female 119 (52)<br />
Male 109 (48)<br />
Marital status<br />
Married/living w ith partner 181 (79)<br />
Other 47 (21)<br />
Education
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High school or less 100 (44)<br />
Some college or more 128 (56)<br />
Smoking status<br />
Households<br />
Never or rarely smoked 97 (43)<br />
Former smoker 94 (41)<br />
Current smoker 37 (16)<br />
Annual income<br />
< $60,000 110 (48)<br />
≥ $60,000 118 (52)<br />
Urbanicity<br />
Rural 37 (16)<br />
Urban 191 (84)<br />
Region of residence<br />
Northeast 41 (18)<br />
Midw est 60 (26)<br />
South 86 (38)<br />
West 41 (18)<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough, cool, and independent. Range: not at all (coded as 1) – very<br />
much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive, immature, inconsiderate, and trashy. Range: not at all (coded<br />
as 1) – very much (5).<br />
Use of e-cigarettes<br />
Only 2 of 228 adolescents (< 1%) had previously tried an e-cigarette. Both of these participants also smoked regular<br />
cigarettes. We excluded these two adolescents from subsequent analyses.<br />
Awareness of e-cigarettes<br />
The majority of adolescents (67%) had heard of e-cigarettes ( Table 2 ). In bivariate analyses, older adolescents were more<br />
likely to be aware of e-cigarettes (Table 2). About three out of four participants ages 14–16 and 17–19 were aware (72% and<br />
76%, respectively) compared to half (52%) of those 11–13 years old. Hispanic/Latino males were less likely to be aware of<br />
e-cigarettes than those of other ethnicities (50% vs. 71%), and white males were more likely to be aware of e-cigarettes than<br />
were other races (71% vs. 53%). Sons of parents with greater than high school education were less likely to be aware of ecigarettes<br />
(61% vs. 76%), as were sons living in urban versus rural areas (64% vs. 83%). Neither parents' nor sons'<br />
smoking status was correlated with having heard of e-cigarettes.<br />
Table 2. Correlates of awareness of e-cigarettes ( n = 226)<br />
Number aware of e-cigarettes/total number in<br />
category (%)<br />
Bivariate Multivariate<br />
n (%) OR (95% CI) OR (95% CI)<br />
Overall 152/226 (67)<br />
Adolescent males'<br />
characteristics<br />
Age<br />
11–13 years (Ref) 33/64 (52) 1 – 1 –<br />
14–16 years 66/92 (72) 2.34 (1.22,<br />
4.65)∗<br />
17–19 years 53/70 (76) 2.93 (1.41,<br />
6.10)∗∗<br />
Hispanic/Latino<br />
2.12 (1.06,<br />
4.26)∗<br />
2.61 (1.21,<br />
5.64)∗<br />
No (Ref) 133/188 (71) 1 – 1 –<br />
Yes 19/38 (50) .41 (.20, .84)∗ .44 (.21,<br />
.95)∗
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b<br />
Race<br />
Non-w hite (Ref) 24/45 (53) 1 – 1 –<br />
White 128/181 (71) 2.11 (1.08,<br />
4.12)∗<br />
Smoking status<br />
Nonsmoker (Ref) 137/207 (66) 1 –<br />
Smoker 15/19 (79) 1.92 (.61, 5.99)<br />
Positive smoker prototype a .78 (.55, 1.09)<br />
Negative smoker prototype<br />
Parents' characteristics<br />
Age<br />
< 45 years (Ref) 89/138 (64) 1 –<br />
.79 (.62, 1.02)<br />
≥ 45 years 63/88 (72) 1.39 (.78, 2.48)<br />
Gender<br />
Female (Ref) 78/118 (66) 1 –<br />
Male 74/108 (69) 1.12 (.64, 1.95)<br />
Marital status<br />
Other (Ref) 30/47 (64) 1 –<br />
Married 122/179 (68) 1.21 (.62, 2.38)<br />
Education<br />
High school or less<br />
(Ref)<br />
1.87 (.92,<br />
3.78)<br />
75/99 (76) 1 – 1 –<br />
Some college or more 77/127 (61) .49 (.28, .88)∗ .59 (.31,<br />
1.10)<br />
Smoking status<br />
Never or rarely smoked<br />
(Ref)<br />
61/97 (63) 1 –<br />
Former smoker 63/92 (68) 1.28 (.70, 2.34)<br />
Current smoker 28/37 (76) 1.84 (.78, 4.32)<br />
Household characteristics<br />
Annual income<br />
< $60,000 (Ref) 71/109 (65) 1 –<br />
≥ $60,000 81/117 (69) 1.20 (.69, 2.10)<br />
Urbanicity<br />
Rural (Ref) 30/36 (83) 1 – 1 –<br />
Urban 122/190 (64) .36 (.14, .91)∗ .54 (.20,<br />
1.43)<br />
Region<br />
Northeast (Ref) 32/41 (78) 1 –<br />
Midw est 41/60 (68) .61 (.24, 1.52)<br />
South 55/84 (65) .53 (.22, 1.27)<br />
West 24/41 (59) .40 (.15, 1.04)<br />
Note. Analyses excluded two adolescents who had previously used e-cigarettes. Multivariate model contains all correlates<br />
statistically significant (p < .05) in bivariate models.<br />
CI = confidence interval; OR = odds ratio; Ref = reference category.<br />
∗ p < .05.
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∗∗ p < .01.<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough, cool, and independent. Range: not at all (coded as 1) – very<br />
much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive, immature, inconsiderate, and trashy. Range: not at all (coded<br />
as 1) – very much (5).<br />
In the multivariate model of sons' awareness, only age and Hispanic ethnicity remained statistically significant. Participants<br />
ages 14–16 were more likely to have heard of e-cigarettes (OR 2.12, 95% CI 1.06, 4.26) compared to participants ages 11<br />
–13, as were participants ages 17–19 (OR 2.61, 95% CI 1.21, 5.64). Hispanic participants were less likely to be aware of ecigarettes<br />
(OR .44, 95% CI .21, .95).<br />
Willingness to try e-cigarettes<br />
A substantial minority of adolescent boys (18%) were willing to try an e-cigarette if it was offered by one of their best friends:<br />
13% were willing to try a plain e-cigarette, and an additional 5% were willing to try flavored e-cigarettes or both kinds. The<br />
same proportion of respondents were willing to try plain e-cigarettes or to try flavored e-cigarettes (p = .15). In bivariate<br />
analyses, adolescent males ages 17–19 were more willing to try an e-cigarette compared to their 11–13- year-old<br />
counterparts (29% vs. 11%) (Table 3 ). The small number of adolescent males who smoked were much more willing to try ecigarettes<br />
(74% vs. 13%) than the remaining respondents. However, sons of parents who were current smokers were less<br />
willing compared to sons of parents who had never or rarely smoked (5% vs. 22%). Sons living in households with annual<br />
incomes of $60,000 or more were also less likely to be willing to try an e-cigarette (13% vs. 24%). Participants willing to try ecigarettes<br />
had less negative beliefs about the typical smoker (mean negative prototype 2.65 vs. 3.35). Prior awareness of ecigarettes<br />
was not associated with willingness to use them (p = .38).<br />
Table 3. Correlates of willingness to try an e-cigarette (plain or flavored) (n = 226)<br />
Number willing to try an e-cigarette/total number<br />
in category (%)<br />
Bivariate Multivariate<br />
n (%) OR (95% CI) OR (95% CI)<br />
Overall 41/226 (18)<br />
Adolescent males'<br />
characteristics<br />
Age<br />
11–13 years (Ref) 7/64 (11) 1 – 1 –<br />
14–16 years 14/92 (15) 1.46 (.55, 3.85) 1.16 (.42, 3.16)<br />
17–19 years 20/70 (29) 3.26 (1.27,<br />
8.35)∗<br />
Hispanic/Latino<br />
Race<br />
No (Ref) 34/188 (18) 1 –<br />
Yes 7/38 (18) 1.02 (.42, 2.52)<br />
Non-w hite (Ref) 8/45 (18) 1 –<br />
White 33/181 (18) 1.03 (.44, 2.42)<br />
Smoking status<br />
1.46 (.49, 4.32)<br />
Nonsmoker (Ref) 27/207 (13) 1 – 1 –<br />
Smoker 14/19 (74) 18.67 (6.22,<br />
55.98)∗∗∗<br />
Positive smoker<br />
prototype a<br />
Negative smoker<br />
prototype b<br />
Aw areness of ecigarettes<br />
1.18 (.79, 1.77)<br />
Not aw are 11/74 (15) 1 –<br />
Aw are 30/152 (20) 1.41 (.66, 3)<br />
Parents' characteristics<br />
Age<br />
< 45 years (Ref) 26/138 (19) 1 –<br />
10.25 (2.88,<br />
36.46)∗∗<br />
∗<br />
.58 (.43, .79)∗∗ .74 (.52, 1.05)
http://www.jahonline.org/article/S1054-139X(12)00409-0/fulltext 7/10<br />
≥ 45 years 15/88 (17) .89 (.44, 1.78)<br />
Gender<br />
Female (Ref) 23/118 (19) 1 –<br />
Male 18/108 (17) .83 (.42, 1.63)<br />
Marital status<br />
Other (Ref) 12/47 (26) 1 –<br />
Married 29/179 (16) .56 (.26, 1.21)<br />
Education<br />
High school or less<br />
(Ref)<br />
Some college or<br />
more<br />
Smoking status<br />
Never or rarely<br />
smoked (Ref)<br />
20/99 (20) 1 –<br />
21/127 (17) .78 (.40, 1.54)<br />
21/97 (22) 1 – 1 –<br />
Former smoker 18/92 (20) .88 (.43, 1.78) .85 (.38, 1.89)<br />
Current smoker 2/37 (5) .21 (.05, .93)∗ .28 (.06, 1.38)<br />
Household characteristics<br />
Annual income<br />
< $60,000 (Ref) 26/109 (24) 1 – 1 –<br />
≥ $60,000 15/117 (13) .47 (.23, .94)∗ .72 (.33, 1.60)<br />
Urbanicity<br />
Rural (Ref) 6/36 (17) 1 –<br />
Urban 35/190 (18) 1.13 (.44, 2.92)<br />
Region<br />
Northeast (Ref) 6/41 (15) 1 –<br />
Midw est 12/60 (20) 1.46 (.50, 4.26)<br />
South 17/84 (20) 1.48 (.54, 4.09)<br />
West 6/41 (15) 1 (.29, 3.40)<br />
Note. Analyses excluded two adolescents who had previously used e-cigarettes. Multivariate model contains all correlates<br />
significant (p < .05) in bivariate models.<br />
CI = confidence interval; OR = odds ratio; Ref = reference category.<br />
∗ p < .05.<br />
∗∗ p < .01.<br />
∗∗∗ p < .001.<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough, cool, and independent. Range: not at all (coded as 1) – very<br />
much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive, immature, inconsiderate, and trashy. Range: not at all (coded<br />
as 1) – very much (5).<br />
Only sons' smoking status remained statistically significant in the multivariate model (OR 10.25, 95% CI 2.88, 36.46).<br />
However, when we excluded sons who smoked (n = 19) from the model, only endorsement of negative smoker prototypes<br />
was statistically significant. That is, willingness to try e-cigarettes was associated with less negative beliefs about the typical<br />
smoker (mean negative prototype 2.83 vs. mean 3.39, OR .58, 95% CI .43, .79). When negative beliefs were dichotomized<br />
using a median split, the association held. More adolescents below or at the median of negative beliefs were willing to try an<br />
e-cigarette compared to adolescents above the median (24% vs. 12%, p = .02).<br />
Back to Article Outline<br />
Discussion<br />
Although few adolescent males in our national sample had tried e-cigarettes, around two-thirds were aware of them. This
http://www.jahonline.org/article/S1054-139X(12)00409-0/fulltext 8/10<br />
figure is much higher than expected, given that only 32% of adults in a national sample were aware of e-cigarettes as of<br />
2010 [5]. The high rate of awareness in our sample may reflect the increasing popularity of and media attention given to the<br />
product [5], [7], [8] or to the rise in e-cigarette promotion in the past 2 years [6], [16]. For example, e-cigarettes are advertised<br />
extensively online, and disposable e-cigarettes are now sold in many convenience stores and gas stations. Our findings<br />
may also reflect higher awareness among adolescents than adults.<br />
Within our sample, older adolescents were more likely to be aware of e-cigarettes than younger adolescents, while Hispanic<br />
adolescents were less likely to be aware compared to their non-Hispanic counterparts. This pattern could reflect greater<br />
awareness of or exposure to all nicotine and tobacco products. Cigarette smoking rates increase with age throughout<br />
adolescence, and Hispanic young adults are less likely to smoke than white young adults [16].<br />
Consistent with findings on adolescent males' susceptibility to regular cigarettes, nearly 1 in 5 adolescent males in our<br />
study were willing to try either a plain or flavored e-cigarette if one of their best friends offered it; willingness to try plain<br />
versus flavored varieties did not differ. This preliminary finding suggests that, at present, candy or fruit flavors do not increase<br />
the attractiveness of e-cigarettes to adolescents. However, before their ban by the FDA in 2009 [23], flavored non-electronic<br />
cigarettes were particularly popular among youth smokers compared to adult smokers, in part due to youth-targeted<br />
advertising [24]. Future marketing of flavored e-cigarettes toward young people could increase the appeal of the product<br />
relative to unflavored e-cigarettes.<br />
Being a smoker was the strongest predictor of willingness to try an e-cigarette. Even after controlling for other statistically<br />
significant correlates, the odds of a smoker being willing to try an e-cigarette were 10 times the odds of a nonsmoker. This<br />
pattern is consistent with survey data showing that most adult e-cigarette users are or were smokers [5]. Because<br />
adolescent smokers exhibit more sensation seeking than nonsmokers [25], smokers may be more willing to try new,<br />
potentially risky behaviors, such as e-cigarette use, than their nonsmoking counterparts. Alternatively, both smoking and<br />
nonsmoking adolescents might view e-cigarettes as similar, or even equivalent, to regular cigarettes. Thus, if they have<br />
already used one product, they are willing to try the other. Similar to adult smokers, young smokers may also be attracted to<br />
e-cigarettes because they view them as a tool to quit smoking, an option for using nicotine in places where smoking is<br />
banned, or a less unpleasant version of regular cigarettes [9], [26].<br />
When we removed smokers from analyses, the only predictor of willingness to try an e-cigarette in multivariate analyses was<br />
smoker prototype. Specifically, having more negative beliefs about the typical smoker was associated with lower willingness.<br />
According to the prototype/willingness model, risky behavior, particularly among adolescents, is driven by a combination of<br />
reasoned cognitions and social reactions [20]. One assumption of the model is that adolescents associate risk behaviors<br />
with specific social images (also called prototypes) of a person who engages in that behavior. Comparing themselves to<br />
that social image influences their willingness and behavior. Thus, associating oneself with positive images of smokers<br />
should predict future smoking behavior, as has been found in longitudinal studies [17]. Our findings are consistent with the<br />
prototype/willingness model. Believing that smokers were unattractive, immature, inconsiderate, or trashy was associated<br />
with reduced interest in trying e-cigarettes, possibly because respondents viewed e-cigarettes as similar—or even the same<br />
—as regular cigarettes. Thus, they were less willing to try a product that they associated with these negative prototypes. In<br />
line with the prototype/willingness model and given that teenagers are already influenced by images of smoking in the<br />
media [27], our findings suggest that presenting negative portrayals of smokers could potentially discourage nonsmokers<br />
from trying e-cigarettes.<br />
Although willingness to use e-cigarettes among nonsmokers was lower than among smokers, even minimal interest<br />
among this population is concerning, given that most adolescent males are nonsmokers [16]. Furthermore, nicotine<br />
dependence can start to occur within weeks of occasional tobacco use [28], so even brief experimentation with nicotinecontaining<br />
e-cigarettes could bolster adolescents' interest in using other tobacco products.<br />
Because this study was cross-sectional, we were not able to assess whether attitudes about smokers influenced<br />
willingness to try e-cigarettes or vice versa. Moreover, we could not address whether participants' attitudes and behaviors<br />
changed over time. Another limitation is that we asked participants about their willingness to try “an e-cigarette” and “a<br />
flavored e-cigarette” without specifying that the former question referred to regular, unflavored e-cigarettes. We also did not<br />
ask e-cigarette users about the duration or frequency of their use or whether they began using e-cigarettes prior to initiating<br />
smoking regular cigarettes. However, the small number of respondents (n = 2) in this group and our study's cross-sectional<br />
design would prevent us from examining the “gateway” hypothesis in any case. Participants self-reported their smoking and<br />
e-cigarette use, but adolescents' self-reported use of regular cigarettes is largely consistent with the results of serum<br />
cotinine testing [29]. Although we examined predictors of self-reported intention, rather than behavior, this choice is<br />
appropriate for studying early adoption of new behaviors [30]. The study benefited from the use of a national sample, which<br />
increases our confidence that the findings may generalize to other U.S. adolescent males.<br />
Should additional studies replicate our findings of high level of awareness and moderate willingness to try e-cigarettes<br />
among adolescent males, the FDA should evaluate devoting regulatory resources toward preventing youth from initiating<br />
use. Specifically, we believe that the FDA should consider implementing a ban on the sale of e-cigarettes to minors and<br />
monitoring advertisements, particularly those for flavored e-cigarettes, to ensure that they do not target youth. As e-cigarette<br />
research continues, it will be important to track the number of youth who initiate e-cigarette use as a precursor to smoking.<br />
Back to Article Outline<br />
References<br />
1. U.S. Food and Drug Administration. Evaluation of e-cigarettes. 2009. Available at:<br />
http://w w w.fda.gov/dow nloads/Drugs/ScienceResearch/UCM173250.pdf.<br />
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4. U.S. Food and Drug Administration. Regulation of e-cigarettes and other tobacco products. 2011. Available at:
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7. Tierney J . A tool to quit smoking has some unlikely critics . New York Times; 2011 Nov 7;<br />
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8. Mishori R . E-cigarettes: Can they help you quit? . Parade Magazine; 2009 July 12;<br />
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9. Etter JF , Bullen C . Electronic cigarette: users profile, utilization, satisfaction and perceived efficacy . Addiction .<br />
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10. Etter JF . Electronic cigarettes: A survey of users . BMC Public Health . 2010;10:231<br />
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11. Foulds J , Veldheer S , Berg A . Electronic cigarettes (e-cigs): View s of aficionados and clinical/public health perspectives .<br />
Int J Clin Pract . 2011;65:1037–1042<br />
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12. Bell K , Keane H . Nicotine control: E-cigarettes, smoking and addiction . Int J Drug Policy . 2012;23:242–247<br />
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13. Borland R . Electronic cigarettes as a method of tobacco control . BMJ . 2011;343:d6269<br />
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14. Cobb NK , Byron MJ , Abrams DB , et al. Novel nicotine delivery systems and public health: The rise of the "e-cigarette." .<br />
Am J Public Health . 2010;100:2340–2342<br />
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15. Riker CA , Lee K , Darville A , et al. E-cigarettes: Promise or peril? . Nurs Clin N Am . 2012;47:159–171<br />
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16. U.S. Department of Health and Human Services . Preventing tobacco use among youth and young adults: A report of the<br />
Surgeon General . Atlanta, GA: Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and<br />
Health Promotion, Office on Smoking and Health; 2012;<br />
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17. Aloise-Young PA , Hennigan KM , Graham JW . Role of the self-image and smoker stereotype in smoking onset during early<br />
adolescence: A longitudinal study . Health Psychol . 1996;15:494–497<br />
View In Article MEDLINE CrossRef<br />
18. Reiter PL , McRee AL , Kadis JA , et al. HPV vaccine and adolescent males . Vaccine . 2011;29:5595–5602<br />
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19. Dennis JM. Description of w ithin-panel survey sampling methodology: The Know ledge Netw orks approach. 2009. Available at:<br />
http://w w w.know ledgenetw orks.com/ganp/docs/KN-Within-Panel-Survey-Sampling-Methodology.pdf.<br />
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20. Gibbons FX , Gerrard M , Lane DJ . A social reaction model of adolescent health risk . In: Suls J , Wallston KA editor. Social<br />
psychological foundations of health and illness . Malden, MA: Blackw ell Publishing Ltd.; 2003;p. 107–136<br />
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21. McCool JP , Cameron L , Petrie K . Stereotyping the smoker: Adolescents' appraisals of smokers in film . Tob Control .<br />
2004;13:308–314<br />
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22. McCool J , Cameron LD , Robinson E . Do parents have any influence over how young people appraise tobacco images in the<br />
media? . J Adolesc Health . 2011;48:170–175<br />
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23. U.S. Food and Drug Administration. Flavored tobacco. 2011. Available at:<br />
http://w w w.fda.gov/TobaccoProducts/ProtectingKidsfromTobacco/FlavoredTobacco/default.htm.<br />
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24. Klein SM , Giovino GA , Barker DC , et al. Use of flavored cigarettes among older adolescent and adult smokers: United<br />
States, 2004–2005 . Nicotine Tob Res . 2008;10:1209–1214<br />
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25. Frankenberger KD . Adolescent egocentrism: A comparison among adolescents and adults . J Adolescence . 2000;23:343<br />
–354<br />
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26. McQueen A , Tow er S , Sumner W . Interview s w ith "vapers": Implications for future research w ith electronic cigarettes .<br />
Nicotine Tob Res . 2011;13:860–867<br />
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27. McCool JP , Cameron LD , Petrie KJ . The influence of smoking imagery on the smoking intentions of young people: Testing<br />
a media interpretation model . J Adolesc Health . 2005;36:475–485<br />
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28. DiFranza JR , Rigotti NA , McNeill AD , et al. Initial symptoms of nicotine dependence in adolescents . Tob Control . 2000;9:313<br />
–319<br />
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29. Caraballo RS , Giovino GA , Pechacek TF . Self-reported cigarette smoking versus serum cotinine among U.S. adolescents .<br />
Nicotine Tob Res . 2004;6:19–25<br />
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30. Gierisch JM , Reiter PL , Rimer BK , et al. Standard definitions of adherence for infrequent yet repeated health behaviors .<br />
Am J Health Behav . 2010;34:669–679<br />
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Funding: Support for this study w as provided by the American Cancer Society (MSRG-06-259-01-CPPB), the Cancer Control Education<br />
Program at UNC Lineberger Comprehensive Cancer Center (R25 CA57726), the National Institutes of Health (P50CA105632 and<br />
P30CA016058), and a NRSA in Primary Medical Care at the University of Minnesota (T32HP22239).<br />
Conflicts of interest: None.<br />
PII: S1054-139X(12)00409-0<br />
doi:10.1016/j.jadohealth.2012.09.014<br />
© 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
53 Singapore-ENDS-study TobaccoControl-2012-<br />
050483.full.
1 Cigarette Testing Laboratory,<br />
Applied Sciences Group, Health<br />
Sciences Authority, Singapore<br />
2 Tobacco Regulation Branch,<br />
Health Products Regulation<br />
Group, Health Sciences<br />
Authority, Singapore<br />
Correspondence to<br />
Dr Nuan Ping Cheah,<br />
Cigarette Testing Laboratory,<br />
Applied Sciences Group,<br />
Health Sciences Authority,<br />
11 Outram Road, Singapore<br />
169078, Singapore;<br />
cheah_nuan_ping@hsa.gov.sg<br />
Received 19 February 2012<br />
Revised 15 October 2012<br />
Accepted 30 October 2012<br />
To cite: Cheah NP,<br />
Chong NWL, Tan J, et al.<br />
Tob Control Published<br />
Online First: 30 November<br />
2012 doi:10.1136/<br />
tobaccocontrol-2012-<br />
050483<br />
Downloaded from<br />
tobaccocontrol.bmj.com on December 2, 2012 - Published by group.bmj.com<br />
TC Online First, published on December 1, 2012 as 10.1136/tobaccocontrol-2012-050483<br />
Research paper<br />
Electronic nicotine delivery systems: regulatory<br />
and safety challenges: Singapore perspective<br />
Nuan Ping Cheah, 1 Norman Wee Lin Chong, 2 Jing Tan, 1 Faridatul Akmam Morsed, 1<br />
Shen Kuan Yee 2<br />
ABSTRACT<br />
Objective Many electronic nicotine delivery systems<br />
(ENDS) are marketed as safer tobacco alternative<br />
products or effective cessation therapies. ENDS samples<br />
were evaluated for design features, including nicotine<br />
and glycols content. This could be useful in developing a<br />
legal framework to handle ENDS.<br />
Methods Identification of the nicotine, glycerol and<br />
propylene glycol (PPG) contents was conducted using<br />
gas chromatography mass spectrometry with<br />
quantification performed using flame ionisation<br />
techniques.<br />
Results Varying nicotine amounts were found in ENDS<br />
cartridges which were labelled with the same<br />
concentration. Chemicals such as PPG and glycerol were<br />
found to be present in the nicotine-containing liquid of<br />
the cartridges. ENDS varied in their contents and<br />
packaging information. Limited information was available<br />
on the contents of nicotine and other chemicals present<br />
in a variety of ENDS sampled.<br />
Conclusions Based on samples tested in this study,<br />
many contain misleading information on product<br />
ingredients. The results show poor consistency between<br />
actual nicotine content analysed on ENDS cartridges and<br />
the amount labelled. These findings raise safety and<br />
efficacy concerns for current and would-be recreational<br />
users or those trying to quit smoking.<br />
INTRODUCTION<br />
Electronic nicotine delivery systems (ENDS), commonly<br />
called electronic cigarettes, e-cigarettes or<br />
vapourisers, are typically battery-operated devices<br />
that are designed and used in the same manner as a<br />
conventional cigarette but claimed to rapidly<br />
deliver nicotine to its users without exposure to<br />
harmful carcinogens and toxicants. Alternative versions<br />
include electronic cigars and shisha pipes. 1<br />
An ENDS product usually consists of a cartridge,<br />
heating element, lithium battery and light-emitting<br />
diode (LED) light which emits a reddish light when<br />
puffed (figure 1). Nicotine refill cartridges are available<br />
in different concentrations ranging from zero<br />
nicotine, low and mid-range doses (eg, 6–8 mg/ml<br />
and 10–14 mg/ml respectively), to high and extrahigh<br />
doses (eg, 16–18 mg/ml and 24–36 mg/ml<br />
respectively). 2 The concentration labels are often<br />
printed on the e-liquid bottle or cartridge.<br />
Without the need for combustion or tobacco,<br />
such devices heat up compounds typically composed<br />
of propylene glycol (PPG) (a known irritant<br />
when inhaled or ingested) and nicotine, which is<br />
vapourised as a mist, providing the sensory and<br />
visual sensation of exhaling ‘smoke’. Manufacturers<br />
often offer such compounds with varying levels of<br />
nicotine and assorted flavours.<br />
Studies done by the US Food and Drug<br />
Administration 3–7 have shown that ENDS may pose<br />
health risks to its users as they may contain toxic<br />
chemicals and other impurities. Moreover, the<br />
amounts of nicotine stated on the nicotine cartridges<br />
did not match with the result of laboratory<br />
analysis, raising concerns about their quality and<br />
safety. 7<br />
To further understand the ENDS product, a<br />
sample of different types of ENDS products was<br />
tested and the content of its main chemicals, nicotine<br />
and glycols, is presented and discussed.<br />
METHODS<br />
Sample and standard preparation<br />
The sale of ENDS is prohibited in Singapore.<br />
The Immigration and Checkpoints Authority of<br />
Singapore provided the samples used in this study<br />
from its seizure operations conducted between<br />
October 2010 and March 2011. Seizures are made<br />
from individuals who attempt to carry in ENDS via<br />
border checkpoints or at parcel screening facilities<br />
when individuals attempt to import ENDS via<br />
internet purchases.<br />
ENDS reviewed in this study were obtained from<br />
seizure samples. A total of 20 variants of ENDS<br />
cartridge were analysed. Each brand was evaluated<br />
on design, nicotine content and labelling information<br />
(table 1).<br />
Determination of nicotine, PPG and glycerol was<br />
carried out using organic solvent extraction followed<br />
by detection by gas chromatography. The<br />
extraction steps are described in detail by Trehy<br />
et al. 3 In addition, the completeness of the extraction<br />
of the studied analyte was re-examined by<br />
re-extracting five of the studied cartridges<br />
(E-vaporizer—16 mg; Smoker Haven; Smoking<br />
Everywhere—Med 11 mg; V2CIGS—Red-12 and<br />
Fifty-One—6 mg). The re-extracted solution was<br />
found to have non-detectable amounts of nicotine,<br />
PPG and glycerol (ie, below the detection level of<br />
the method). We obtained recovery between 80%<br />
and 90% using the laboratory fortified matrix with<br />
known concentration between the low and high<br />
levels of all three chemicals studied (nicotine, PPG<br />
and glycerol). The detection limits for this method<br />
were 0.02 mg for nicotine, 0.5 mg for PPG and<br />
0.5 mg for glycerol. A series of standard solutions<br />
were prepared by dissolving reference standards in<br />
methanol. The correlation coefficient of the calibration<br />
curve (R 2 ) was >0.995. The analysis was conducted<br />
in triplicate (ie, test on three cartridges per<br />
product) per brand.<br />
Copyright Article author (or their employer) 2012. Produced by BMJ Publishing Group Ltd under licence.<br />
Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483 1
Research paper<br />
Figure 1 ‘eGo’ manufactured by<br />
JOYE Technology, China. The design of<br />
the eGo electronic cigarette differs<br />
from conventional designs that<br />
resemble conventional cigarettes,<br />
purportedly to allow the user to vape<br />
more discretely in public. Although its<br />
shape is closer to that of a cigar, the<br />
black rubberised exterior and silver/<br />
gold finishing makes this design less<br />
similar to a tobacco product. Another<br />
unique feature of this design is the<br />
presence of a button, which allows<br />
users to activate the atomiser without<br />
initiating the first puff (http://<br />
jantyworld.com).<br />
Downloaded from<br />
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Materials and instrument<br />
The standard of nicotine (99.7%) was obtained from Merck<br />
Chemicals. Glycerol (99.5%) and PPG (99.5%) were from<br />
Sigma-Aldrich. Other chemicals and solvents used were of analytical<br />
or high-performance liquid chromatography grade. Gas<br />
chromatography with flame ionisation detector (Agilent 6890 N<br />
Series) was used to quantify the content of nicotine, PPG and<br />
glycerol in ENDS. A J&W DB-Wax capillary column coated<br />
with a 1 μm thick polyethylene glycol (30 m×0.53 mm) was<br />
used for the analysis. Each compound was identified using the<br />
same instrument with mass spectrometer detection.<br />
RESULTS<br />
The vast majority of the 20 brands of ENDS provided information<br />
on the health impact of ENDS use and the risk of nicotine<br />
addiction (table 1). All 20 brands of ENDS evaluated in this<br />
study were marketed as safer and healthier alternatives to conventional<br />
smoking, or as smoking cessation aids.<br />
Twelve brands included some form of health caution, with a<br />
warning for users who are under 18 years, pregnant or who<br />
have a heart condition, diabetes, high blood pressure or asthma.<br />
Only two brands provided a warning on nicotine addiction.<br />
Seventeen products were found to contain detectable<br />
amounts of nicotine (table 2). Four of the 20 brands sampled<br />
were found to contain nicotine even though these products<br />
claimed to be nicotine free. Across the 20 products, nicotine<br />
content ranged up to 15.3 mg per cartridge, PPG content<br />
ranged up to 1020 mg per cartridge and glycerol content ranged<br />
from 19.4 to 1020 mg per cartridge. In 16 of the 20 brands<br />
sampled, actual nicotine content did not correspond to the<br />
amount that the cartridge purported to contain.<br />
Two products contained a very high level of glycerol (w/w):<br />
e-joy with 374 mg and Fifty-One with 827 mg (labelled as<br />
6 mg). Eighteen products were found to contain more than<br />
100 mg of PPG per cartridge.<br />
Polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific<br />
nitrosamine compounds were not found in the ENDS cartridges<br />
in this study. This is expected as tobacco-specific nitrosamines<br />
are mostly formed during the ageing, curing and fermentation<br />
of tobacco, whereas PAHs are smoke compounds formed due to<br />
incomplete combustion of organic materials. Descriptions and<br />
illustrations of four ENDS products are included in figures 1–5.<br />
DISCUSSION<br />
Labelling of constituents and health information on the 20<br />
brands of ENDS sampled was inadequate. About half of the<br />
sampled brands did not label the nicotine amounts on the packaging<br />
and did not provide any health caution on risks of nicotine<br />
use, particularly to at-risk subpopulations like pregnant<br />
women and minors. The majority of the brands sampled were<br />
found to have inaccurate nicotine labelling and did not give the<br />
amount of nicotine on the individual cartridge wrapper, consistent<br />
with previously published work. 8 Future regulation of<br />
ENDS should determine appropriate warnings on the risks and<br />
harm associated with nicotine exposure due to inhalation and<br />
mishandling. In addition, our findings show that there is significant<br />
difference in the nicotine content across ENDS of the same<br />
concentration label. There are brand-to-brand and cartridgeto-cartridge<br />
variations. ENDS that contain low amounts of<br />
nicotine may have the potential to serve as a starting point for<br />
would-be tobacco users. 9 High concentrations of nicotine in<br />
ENDS may pose other risks. For example, an estimated level of<br />
10 mg nicotine can be fatal to children. 10 The effectiveness of<br />
nicotine delivery in such devices is still in question, with competing<br />
views on the use of such products as gateways to tobacco<br />
use 9 or as cessation aids, like nicotine replacement therapy.<br />
11 12<br />
Due to its odourless and smokeless delivery system, the<br />
e-cigarette can be used in non-smoking areas, as suggested by<br />
some ENDS product inserts. This has the potential to allow<br />
people to satisfy the smoking urge despite being in areas where<br />
smoking is prohibited.<br />
The presence of a high amount of glycols (PPG and glycerol)<br />
in great quantities in these devices raises another concern. PPGs,<br />
the main liquid found in the cartridge, is a non-toxic chemical<br />
widely used as humectants in food products and as additives in<br />
asthma inhalers and nebulisers. Unlike inhalers or nebulisers,<br />
2 Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483
Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483 3<br />
Table 1 Product and labelling information of 20 variants of electronic nicotine delivery system (ENDS) cartridges seized by Singapore Customs<br />
No Sample<br />
1 V2CIGS<br />
(Red-12)<br />
2 V2CIGS<br />
(Red-Full<br />
18 mg)<br />
3 Personal<br />
Vaporizer 510<br />
(Med)<br />
Cartridge<br />
colour<br />
Cartridge<br />
leak Manufacturer<br />
Blue No VMR Products<br />
LLC<br />
Red No VMR Products<br />
LLC<br />
Black Yes Shenzhen<br />
Kangshengda<br />
Technology Co<br />
4 Smoker Haven Black No SmokerHaven<br />
Electronic<br />
Cigarette<br />
5 Super<br />
Cigarette<br />
(Med 14 mg)<br />
Nicotine<br />
amount<br />
given on<br />
packaging Health statements Health caution<br />
12 mg V2 electronic cigarettes are designed to give you<br />
a similar experience to smoking cigarettes, but<br />
with substantially less health risk than<br />
traditional smoking<br />
18 mg V2 electronic cigarettes are designed to give you<br />
a similar experience to smoking cigarettes, but<br />
with substantially less health risk than<br />
traditional smoking<br />
Not stated The main ingredients of the liquid are water and<br />
non-carcinogenic and non-toxic common legal<br />
food and taste additives<br />
Not stated Nicotine by itself is not dangerous. It is just like<br />
caffeine in coffee. It is addictive but not<br />
dangerous. In fact nicotine in cigarettes is not<br />
dangerous, the burning process and other 4000<br />
chemicals is the one that is dangerous like tar,<br />
carbon monoxide, carcinogens<br />
Beige No Not stated 14 mg It cares for your health, creating more healthy<br />
smoking experience and has become popular as<br />
the best alternative to smoking up to the<br />
present<br />
6 e-joy White No Everbright<br />
Technologies Co<br />
7 E-vaporizer<br />
(16 mg)<br />
8 Smoking<br />
Anywhere<br />
9 Simple<br />
Smoker<br />
10 Eluma<br />
(12 mg)<br />
Beige No Longmada<br />
Technology Co<br />
Not stated Electronic cigarettes do not contain tobacco, tar,<br />
real smoke nor other chemicals like traditional<br />
cigarettes<br />
Warning on<br />
nicotine<br />
addiction<br />
For<br />
adult<br />
use<br />
only<br />
label<br />
Nicotine<br />
label on<br />
wrapper<br />
Nicotine<br />
label on<br />
individual<br />
cartridge<br />
If you are allergic to nicotine or any combination of<br />
inhalants, if you are pregnant and breastfeeding, or<br />
if you have a heart condition, diabetes, high blood<br />
pressure or asthma, consult your physician before<br />
using V2 nicotine products<br />
Not stated Yes Yes Yes<br />
If you are allergic to nicotine or any combination of<br />
inhalants, if you are pregnant and breastfeeding, or<br />
if you have a heart condition, diabetes, high blood<br />
pressure or asthma, consult your physician before<br />
using V2 nicotine products<br />
Not stated Yes Yes Yes<br />
Not stated Not stated Not<br />
stated<br />
Not stated Not stated<br />
Not for non-smokers, pregnant women,<br />
breastfeeding women, and persons with or at risk<br />
of heart disease, high blood pressure, diabetes,<br />
taking medicine for depression or asthma. Consult<br />
a physician if you experience nicotine misuse<br />
symptoms such as nausea, vomiting, dizziness,<br />
weakness or rapid heartbeat<br />
Yes Yes Not stated Not stated<br />
Not stated Not stated Not<br />
stated<br />
Not stated Not stated<br />
Not stated Not stated Not<br />
stated<br />
16 mg Not stated Not smoking at all is always the healthiest choice!<br />
Also, women who are pregnant should not smoke,<br />
not even the electronic cigarette. If you have<br />
doubts about the use of electronic cigarettes, which<br />
may have an impact on health, please consult your<br />
family doctor<br />
Beige No Not stated 1.7 mg Congratulations on your beginning to choose a<br />
healthy lifestyle which will also create a healthy<br />
and environmental-friendly living space for both<br />
you and your family<br />
White No Not stated Not stated The cartridges do not contain tar and nicotine<br />
thus they are health-friendly products<br />
White No Eluma Cigs, LLC 12 mg The main difference is there’s no tobacco so no<br />
tar, ash, odour or carcinogens<br />
Minors under the age of 18, people without the<br />
habit of smoking, people allergic to nicotine or any<br />
components of inhalants and breastfeeding women<br />
Not stated Not stated Not<br />
stated<br />
Persons under 18 years of age are not permitted to<br />
use or purchase Eluma. Non-smokers, children,<br />
women who are pregnant, women breastfeeding or<br />
people at risk from heart disease, high blood<br />
pressure, diabetes, or taking medicine for<br />
depression or asthma should not use this product<br />
Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Continued<br />
Research paper<br />
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4 Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483<br />
Table 1 Continued<br />
No Sample<br />
11 E-cigarette<br />
Create<br />
Healthy Life<br />
12 Slim<br />
E-cigarette<br />
13 Fifty-One<br />
(6 mg)<br />
14 Best Ecig<br />
(24 mg)<br />
Cartridge<br />
colour<br />
Cartridge<br />
leak Manufacturer<br />
Beige No Hong Kong<br />
Famouse<br />
Technology Co<br />
Pink No Shenzhen<br />
Transpring<br />
Enterprise<br />
Beige No Shenxhen<br />
Simeiyue<br />
Technology Co<br />
Black No Best Ecig<br />
Electronic<br />
Technology Co<br />
15 E-pipe (0 mg) Beige No E-Cig technology<br />
Inc<br />
Nicotine<br />
amount<br />
given on<br />
packaging Health statements Health caution<br />
Not stated We believe that electronic cigarette will be able<br />
to eradicate tobacco smoke harmful to human<br />
magic<br />
Unsuitable users: those under the age of 18,<br />
people without the habit of smoking, pregnant and<br />
breast feeding women<br />
Warning on<br />
nicotine<br />
addiction<br />
Not stated Not stated Not stated Not stated Not<br />
stated<br />
6 mg The Fifty-One electronic cigarette is a<br />
revolutionary, innovative device which offers<br />
those who already smoke a better smoking<br />
alternative to traditional tobacco cigarettes<br />
24 mg Tomatoes also contain nicotine but do not cause<br />
harm to the human body. The real injury to the<br />
human body is not from nicotine, but from tar.<br />
The e-cigarette does not contain tar<br />
This product in no way intends to diagnose, treat,<br />
cure or mitigate any disease or condition<br />
Unsuitable users: people under the age of 18,<br />
people without the habit of smoking, pregnant and<br />
breast feeding women<br />
0 mg The healthiest pipe you will ever get E-pipe is for the adults who are smoking, not for<br />
the young people under the legal age, not for<br />
pregnant women or other people who are not<br />
suitable for smoking<br />
16 Vapor (0 mg) Beige No Not stated 0 mg Our new smoking alternative has no tar or<br />
carbon monoxide provides a satisfying smoking<br />
experience and can be used inside and even in<br />
planes<br />
17 Smoking<br />
Everywhere<br />
(Med 11 mg)<br />
Beige No Shenzhen Boge<br />
Technology Co<br />
18 Pons Black No Bilstar<br />
International<br />
19 Victorian<br />
Classic<br />
20 BoJinQiShi<br />
(Platinum<br />
Knight)<br />
Black No Ecig<br />
International<br />
Beige No Zhejiang Fu<br />
Electronics Co<br />
11 mg Smokers can finally get their nicotine fix,<br />
without experiencing the harmful side effects<br />
attributed to the tar contained in real tobacco<br />
products<br />
Not stated The liquid container contains nicotine diluents<br />
which are ready to be atomised; it does not<br />
contain ingredients harmful to human body,<br />
such as tar and carcinogenic substances.<br />
Not stated Nicotine in itself is not harmful. It is addictive<br />
like caffeine in coffee but nicotine is not<br />
dangerous when inhaled<br />
Not stated It’s the world’s latest technology and does not<br />
contain nicotine, tar, benzene, carbon monoxide<br />
For<br />
adult<br />
use<br />
only<br />
label<br />
Not stated Not stated Not<br />
stated<br />
Nicotine<br />
label on<br />
wrapper<br />
Nicotine<br />
label on<br />
individual<br />
cartridge<br />
Not stated Yes Not stated Not stated<br />
Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Not stated Yes Not stated Not stated<br />
Not stated Not stated<br />
Smoking Everywhere Electronic Cigarette is<br />
intended for use by adult smokers and not<br />
intended for pregnant women or those who are<br />
sensitive to nicotine. Nicotine is highly addictive<br />
and may be dangerous to your health. Smoking<br />
Everywhere Electronic Cigarette is not intended as<br />
a smoking cessation device<br />
Yes Yes Not stated Not stated<br />
Prevent contact with mucous membranes; avoid<br />
overexposure to skin and body. For your safety, do<br />
not overuse, apply ONLY as directed. Must be<br />
18 years of age to purchase/use.<br />
Not stated Yes Not stated Not stated<br />
Not stated Not stated Not<br />
stated<br />
Not stated Not stated<br />
Not stated Not stated Not<br />
stated<br />
Not stated Not stated<br />
Research paper<br />
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Table 2 Nicotine, propylene glycol (PPG) and glycerol content of 20 variants of electronic nicotine delivery system (ENDS) cartridges, seized by<br />
Singapore Customs<br />
ENDS cartridge Nicotine content (mg/cartridge) PPG content (mg/cartridge) Glycerol content (mg/cartridge)<br />
V2CIGS (Red-12) 10.3–15.3 581–834 105–142<br />
V2CIGS (Red-Full 18 mg) 10–13.8 697–719 163–222<br />
Personal Vaporizer 510 (Med) 5.4–7.01 308–358 76.6–108<br />
Smoker Haven 2.64–3.06 215–247 58.6–65.4<br />
Super Cigarette (Med 14 mg) 1.51–1.75 218–228 51.7–62.5<br />
e-joy 6.68–7.7 19.7–41.3 311–412<br />
E-vaporizer (16 mg) 4.62–5.56 249–276 38.9–44.6<br />
Smoking Anywhere 0.65–1.13 89.4–152 19.4–24.2<br />
Simple Smoker Not detected 175–201 53.5–59<br />
Eluma (12 mg) 6.9–8.83 444–546 155–179<br />
E-cigarette Create Healthy Life 3.58–4.33 255–292 32.2–35.3<br />
Slim E-cigarette Not detected 140–180 42.7–53.9<br />
Fifty-One (6 mg) 6.26–12.3 0–9.17 444–1020<br />
Best Ecig (24 mg) 2.72–3.73 188–235 34.9–47.1<br />
E-pipe (0 mg) 0–1 641–1320 142–359<br />
Vapor (0 mg) Not detected 155–177 53.9–65.3<br />
Smoking Everywhere (Med 11 mg) 2.24–2.72 231–268 40.2–48.3<br />
Pons 6.09–8.71 216 –428 69.5–82<br />
Victorian Classic 9.2–12 269–440 102–125<br />
BoJinQiShi (Platinum Knight) 6.61–9.97 326–369 110–157<br />
the e-cigarette device consists of a heating component and the<br />
heating of glycols (PPGs or glycerols) generates various carbo-<br />
13 14<br />
nyls which are toxic to the users.<br />
There are additional safety concerns associated with these<br />
products. Carbonyls such as acetaldehyde (0–14 mg/m 3 ),<br />
formaldehyde (0–97 mg/m 3 ), acrolein (0–9.3 mg/m 3 ), glyoxal<br />
(0–42 mg/m 3 ) and methylglyoxal (0–38 mg/m 3 ) have been<br />
detected in the air generated from electronically heated cigarettes.<br />
15 Methylglyoxal, the most mutagenic of all aldehydes, is<br />
known to inhibit formaldehyde metabolism, thus enhancing<br />
Figure 2 ‘SGS electronic cigarette’<br />
manufactured by Wiwin Industry Co,<br />
China. The packaging of the SGS<br />
electronic cigarette very closely<br />
resembles the Marlboro conventional<br />
cigarette packaging. The design and<br />
colour of the battery and cartridge<br />
closely resemble a typical cigarette.<br />
The amber light-emitting diode which<br />
lights up during puff inhalation also<br />
adds to the illusion of smoking.<br />
Although there is no evidence to show<br />
that any conventional cigarette<br />
company has a stake in this product,<br />
the red chevron design of the<br />
packaging (which serves as a charger<br />
for the electronic cigarette battery)<br />
resembles similar branding of a<br />
conventional cigarette brand. (No<br />
independent marketing website found<br />
at time of print.)<br />
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Research paper<br />
formaldehyde-inducing cytotoxicity. 16 High concentrations<br />
of short-chain aldehydes such as formaldehyde, acetaldehyde<br />
and acrolein are produced during the heating of ENDS.<br />
Formaldehyde, a chemical used in wood preservation and<br />
embalming, is classified as carcinogenic to humans by the<br />
International Agency for Research on Cancer (IARC) and is suspected<br />
to be the cause of various diseases (IARC 2006).<br />
Acetaldehyde is known to contribute to tobacco’s addictive<br />
properties. 17 18 The safety of the combination substances that<br />
are delivered to the lungs by ENDS has not been evaluated for<br />
Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483 5
Research paper<br />
Figure 3 ‘Tattoo’ manufactured by<br />
Smoke Free Electronic Cigarettes,<br />
China. While its mechanism is no<br />
different from other brands of<br />
electronic cigarettes, its branding is<br />
unique. Touting to be inspired by<br />
designs of a famous US tattoo artist,<br />
Ed Hardy, its ‘Tattoo’ branding could<br />
arguably be geared towards the<br />
younger target audience. Its marketing<br />
strategies include packaging the<br />
product in collectable tattoo designed<br />
boxes with messages like ‘Take control<br />
of your life! No more letting other<br />
people tell you when or where you can<br />
smoke!’ and ‘Join the smoke free<br />
electronic cigarette revolution! Be<br />
bold! Be unique! Be you!’ Available in<br />
black, white, gold, silver, red and pink,<br />
it may be argued that certain colour<br />
schemes may attract particular<br />
consumer populations, such as young<br />
women (http://www.smokefreeonline.<br />
com).<br />
either short-term or long-term use, making toxicological evaluation<br />
challenging.<br />
The current study is limited to the 20 ENDS products confiscated<br />
from the Immigration and Checkpoints authority, and<br />
thus may not be a conclusive representation of all other ENDS<br />
products on the market. Evaluation of the ENDS products is<br />
limited to the content of the electronic cigarette cartridges.<br />
CONCLUSION<br />
In the realm of public health, more knowledge on the toxicological<br />
effects and risk assessment of ENDS is needed. These<br />
novelty tobacco-related products may not fit neatly under<br />
Figure 4 ‘Super eGo’ manufactured<br />
by E-Cig Technology Inc, China. The<br />
Super eGo claims to offer different<br />
battery amperages. Stronger batteries<br />
are claimed to provide users with<br />
longer-lasting use, be able to provide<br />
deeper inhalation and higher nicotine<br />
‘hits’ compared with other brands of<br />
ENDS. Variants come in three-piece or<br />
two-piece formats. The three-piece<br />
formats are made up of the battery,<br />
atomiser and cartridge whereas the<br />
two-piece formats are made up of the<br />
battery and cartomiser. The cartomiser<br />
serves as the replaceable integrated<br />
combination of the atomiser and<br />
cartridge. The two-piece format aims<br />
to appeal to users who find cleaning<br />
and replacing faulty atomisers<br />
inconvenient (http://www.gatorvapor.<br />
com/super_ego.html).<br />
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conventional classifications of pharmaceutical or tobacco products.<br />
This may pose a challenge for many regulatory bodies to<br />
regulate these products within existing laws.<br />
While the current attention on traditional tobacco products is<br />
important, it is also necessary to focus on novelty products like<br />
ENDS, which may encourage maintenance of tobacco usage<br />
behaviour and slow down the impact of national smoking<br />
control programmes.<br />
Tobacco control policy makers and professionals are seriously<br />
urged to find ways to address the gap in the scientific understanding<br />
and the legal framework of such products, as this gap<br />
may impede efforts at curbing tobacco use.<br />
6 Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483
Figure 5 ‘E-pipe’ manufactured by<br />
E-Cig Technology Inc, China. A variant<br />
design from the e-cigarette, which<br />
could appeal to a niche target<br />
audience of pipe users, the E-pipe<br />
contains the basic components of its<br />
e-cigarette peer: the battery, atomiser,<br />
cartridge and the additional inhaler<br />
mouth piece which comes in contact<br />
with the lips. The E-pipe also contains<br />
a red light-emitting diode which<br />
activates during puffing, adding to the<br />
illusion of smoking a conventional pipe<br />
(http://www.e-cig.com).<br />
What this study adds<br />
Downloaded from<br />
tobaccocontrol.bmj.com on December 2, 2012 - Published by group.bmj.com<br />
▸ While the marketing and product ranges of electronic<br />
nicotine delivery systems (ENDS) have grown in recent years,<br />
questions on the safety and efficacy of these products as<br />
cessation tools have not been fully addressed. Preliminary<br />
tests by the US Food and Drug Administration found varying<br />
levels of nicotine, carcinogens and diethylene glycol in some<br />
samples, highlighting concerns on quality control and<br />
potential toxicity to users. Trtchounian’s examination of six<br />
brands of ENDS suggested a lack of adequate labelling and<br />
raised questions on quality control. Our study of 20 brands<br />
of ENDs provides further data on inconsistencies in the<br />
amount of nicotine found in cartridges compared with the<br />
labelling and the pervasiveness of misleading information on<br />
product labelling and packaging. This supports the current<br />
literature and regulators’ concerns of questionable safety<br />
and quality of ENDS and highlights the need for more<br />
research to help regulators make empirically based policy<br />
decisions.<br />
Acknowledgements The authors would like to thank the Health Sciences<br />
Authority for supporting this project. The authors thank Dr Reinskje Talhout and the<br />
anonymous reviewers for their constructive comments and suggestions.<br />
Contributors NPC handled the conceptualisation, analysis and interpretation of<br />
the quantitative aspects of ENDS constituents. NPC wrote the toxicological section<br />
and integrated all information gathered in this paper. NC handled the acquisition,<br />
qualitative review of ENDS samples and packaging information, and assisted NPC in<br />
the drafting, revision and approval of the final version of the paper. JT organised the<br />
analytical and chemical analysis section. FAM analysed, tabulated and interpreted<br />
the chemical part of the work. SKY provided writing assistance and technical advice<br />
on the regulatory aspects of the paper. All the named authors contributed<br />
substantially to the writing of this paper. NPC, NC and the rest of the authors<br />
approve the concept, approach and the final version of this paper.<br />
Funding This study was funded by ASG Research Fund (ASG07/10), Health<br />
Sciences Authority, Singapore.<br />
Competing interests None.<br />
Research paper<br />
Provenance and peer review Not commissioned; externally peer reviewed.<br />
Data sharing statement Additional unpublished information and data are<br />
available to the editorial team and reviewers upon request.<br />
REFERENCES<br />
1 Yuan R. Electronic Shisha Charcoal. Hunan, China: Hunan Ren Yuan Group<br />
Industrial Corporation.<br />
2 Health New Zealand. The Ruyan E-cigarette. Christchurch: Health New Zealand.<br />
2007.<br />
3 Trehy ML, Ye W, Hadwiger ME, et al. Analysis of electronic cigarette cartridges,<br />
refill solutions, and smoke for nicotine and nicotine related impurities. J Liquid<br />
Chromatogr Relat Technol 2011;34:1442–56.<br />
4 FDA. Summary of Results: Laboratory Analysis of Electronic Cigarettes Conducted by<br />
FDA. Silver Spring, Maryland: US Food and Drug Administration. 2009.<br />
5 FDA. FDA Warns of Health Risks Posed by E-cigarettes. Silver Spring, Maryland: US<br />
Food and Drug Administration. 2009.<br />
6 FDA. Concerns Voiced by the Public Health Experts about Electronic Cigarettes.<br />
Silver Spring, Maryland: US Food and Drug Administration. 2009.<br />
7 FDA. Electronic Cigarettes. Silver Spring, Maryland: US Food and Drug<br />
Administration. 2010.<br />
8 Trtchounian A, Williams M, Talbot P. Conventional and electronic cigarettes<br />
(e-cigarettes) have different smoking characteristics. Nicotine Tob Res<br />
2010;12:905–12.<br />
9 Henningfield JE, Zaatari GS. Electronic nicotine delivery systems: emerging science<br />
foundation for policy. Tob Control 2010;19:89–90.<br />
10 Etter JF, Bullen C, Flouris AD, et al. Electronic nicotine delivery systems: a research<br />
agenda. Tob Control 2011;20:243–8.<br />
11 Eissenberg T. Electronic nicotine delivery devices: ineffective nicotine delivery and<br />
craving suppression after acute administration. Tob Control 2010;19:87–8.<br />
12 Foulds J, Veldheer S, Berg A. Electronic cigarettes (e-cigs): views of aficionados and<br />
clinical/public health perspectives. Int J Clin Pract 2011;65:1037–42.<br />
13 Uchiyama S, Inaba Y, Kunugita N. Determination of acrolein and other carbonyls in<br />
cigarette smoke using coupled silica cartridges impregnated with hydroquinone and<br />
2,4-dinitrophenylhydrazine. J Chromatogra A 2010;1217:4383–8.<br />
14 WHO. The Scientific Basis of Tobacco Product Regulation. World Health<br />
Organization Technical Report Series. Geneva: WHO. 2008.<br />
15 Uchiyama SI, Kunugita N. Determination of acrolein and other carbonyls in cigarette<br />
smoke using coupled silica cartridges impregnated with hydroquinone and<br />
2,4-dinitrophenylhydrazine. J Chromatogra A 2010;1217:4383–8.<br />
16 Teng S, Beard K, Pourahmad J, et al. The formaldehyde metabolic detoxification<br />
enzyme systems and molecular cytotoxic mechanism in isolated rat hepatocytes.<br />
Chem Biol Interact 2001;130–132:285–96.<br />
17 International Agency for Research on Cancer. Formaldehyde, 2-Butoxyethanol and<br />
1-tert-Butoxypropan-2-ol. IARC Monographs on the Evaluation of Carcinogenic<br />
Risks to Humans, Vol.88, Lyon, France: IARC, 2006.<br />
18 Talhout R, Opperhuizen A, van Amsterdam JG. Role of acetaldehyde in tobacco<br />
smoke addiction. Eur Neuropsychopharmacol 2007;17:627–36.<br />
Cheah NP, et al. Tob Control 2012;0:1–7. doi:10.1136/tobaccocontrol-2012-050483 7
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References<br />
Email alerting<br />
service<br />
Electronic nicotine delivery systems:<br />
regulatory and safety challenges: Singapore<br />
perspective<br />
Nuan Ping Cheah, Norman Wee Lin Chong, Jing Tan, et al.<br />
Tob Control published online December 1, 2012<br />
doi: 10.1136/tobaccocontrol-2012-050483<br />
Updated information and services can be found at:<br />
http://tobaccocontrol.bmj.com/content/early/2012/11/30/tobaccocontrol-2012-050483.full.html<br />
These include:<br />
This article cites 10 articles, 4 of which can be accessed free at:<br />
http://tobaccocontrol.bmj.com/content/early/2012/11/30/tobaccocontrol-2012-050483.full.html#re<br />
f-list-1<br />
P
Nachschlagewerk zum Thema E-Zigaretten<br />
54 Adolescent Males Awareness of and Willingness<br />
to Try Electronic Cigarettes
Original article<br />
Adolescent Males’ Awareness of and Willingness to Try Electronic Cigarettes<br />
Jessica K. Pepper, M.P.H. a,b , Paul L. Reiter, Ph.D. c , Annie-Laurie McRee, Dr.P.H. d ,<br />
Linda D. Cameron, Ph.D. e , Melissa B. Gilkey, Ph.D. b , and Noel T. Brewer, Ph.D. a,b, *<br />
a<br />
Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina<br />
b<br />
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina<br />
c<br />
Division of Cancer Prevention and Control, College of Medicine, The Ohio State University, Columbus, Ohio<br />
d<br />
Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota<br />
e<br />
Psychological Sciences, School of Social Sciences, Humanities, and Arts, University of California, Merced, California<br />
Article history: Received June 19, 2012; Accepted September 19, 2012<br />
Keywords: Electronic cigarette; Adolescents; Males; Nicotine; Smoking; Awareness<br />
A B S T R A C T<br />
See Related Editorial p. 135<br />
Purpose: Electronic cigarettes (e cigarettes) are a new type of device that delivers vaporized<br />
nicotine without the tobacco combustion of regular cigarettes. We sought to understand aware<br />
ness of and willingness to try e cigarettes among adolescent males, a group that is at risk for<br />
smoking initiation and may use e cigarettes as a “gateway” to smoking.<br />
Methods: A national sample of 11e19 year old males (n 228) completed an online survey in<br />
November 2011. We recruited participants through their parents, who were members of a panel of<br />
U.S. households constructed using random digit dialing and addressed based sampling.<br />
Results: Only two participants (< 1%) had previously tried e cigarettes. Among those who had not<br />
tried e cigarettes, most (67%) had heard of them. Awareness was higher among older and non<br />
Hispanic adolescents. Nearly 1 in 5 (18%) participants were willing to try either a plain or<br />
flavored e cigarette, but willingness to try plain versus flavored varieties did not differ. Smokers<br />
were more willing to try any e cigarette than nonsmokers (74% vs. 13%; OR 10.25, 95% CI 2.88,<br />
36.46). Nonsmokers who had more negative beliefs about the typical smoker were less willing to<br />
try e cigarettes (OR .58, 95% CI .43, .79).<br />
Conclusions: Most adolescent males were aware of e cigarettes, and a substantial minority were<br />
willing to try them. Given that even experimentation with e cigarettes could lead to nicotine<br />
dependence and subsequent use of other tobacco products, regulatory and behavioral interven<br />
tions are needed to prevent “gateway” use by adolescent nonsmokers. Campaigns promoting<br />
negative images of smokers or FDA bans on sales to youth may help deter use.<br />
Ó 2013 Society for Adolescent Health and Medicine. All rights reserved.<br />
Funding: Support for this study was provided by the American Cancer Society<br />
(MSRG-06-259-01-CPPB), the Cancer Control Education Program at UNC Lineberger<br />
Comprehensive Cancer Center (R25 CA57726), the National Institutes of<br />
Health (P50CA105632 and P30CA016058), and a NRSA in Primary Medical Care<br />
at the University of Minnesota (T32HP22239).<br />
Conflicts of interest: None.<br />
* Address correspondence to: Noel T. Brewer, Ph.D., Gillings School of Global<br />
Public Health, Department of Health Behavior, University of North Carolina at<br />
Chapel Hill, 325A Rosenau Hall, CB 7440, Chapel Hill, NC 27599-7440.<br />
E-mail address: ntb@unc.edu (N.T. Brewer).<br />
Journal of Adolescent Health 52 (2013) 144 150<br />
1054-139X/$ see front matter Ó 2013 Society for Adolescent Health and Medicine. All rights reserved.<br />
http://dx.doi.org/10.1016/j.jadohealth.2012.09.014<br />
www.jahonline.org<br />
IMPLICATIONS AND<br />
CONTRIBUTION<br />
Electronic cigarettes may<br />
be a "gateway" to future<br />
smoking. In this national<br />
sample, most adolescent<br />
males had heard of<br />
electronic cigarettes, and<br />
a substantial minority<br />
were willing to try them.<br />
Regulatory bodies and<br />
health professionals who<br />
work with adolescents<br />
should monitor use of<br />
this increasingly popular<br />
nicotine delivery device.<br />
Electronic cigarettes (e cigarettes) are battery operated<br />
devices that are typically made to look and perform like<br />
regular cigarettes. They contain an inhalation activated mecha<br />
nism that heats liquid from a cartridge composed of humectants<br />
and nicotine, although non nicotine e cigarettes are also avail<br />
able. Users, sometimes called “vapers,” inhale the resulting<br />
vapor. Safety data on e cigarettes are sparse and inconsistent
[1,2], giving rise to considerable concern about the lack of quality<br />
control in manufacturing [3]. The U.S. Food and Drug Adminis<br />
tration (FDA) is working to regulate e cigarettes as tobacco<br />
products [4], but regulations are not yet in place.<br />
While fewer than 3% of American adults had used e cigarettes<br />
as of 2010 [5], public interest is skyrocketing [6], and the popular<br />
media (e.g., New York Times; Parade Magazine) has covered them<br />
extensively [7,8]. Existing research suggests that smokers are more<br />
likely than nonsmokers to try e cigarettes [5]. The most frequently<br />
cited reason for use among “vapers” is to help them quit smoking<br />
or reduce use of traditional cigarettes [9e11]. Given the unknown<br />
long term consequences of e cigarette use and the lack of<br />
comprehensive data on product safety or utility as a cessation aid,<br />
the public health and tobacco control communities are both<br />
strongly divided about whether e cigarettes are dangerous or<br />
a promising harm reduction strategy for adult smokers [12e15].<br />
Tobacco control advocates and researchers are also concerned<br />
that e cigarettes could act as “gateway” devices, getting novice<br />
users, particularly young people, addicted to nicotine and<br />
encouraging future tobacco use [15]. Given that most tobacco use<br />
begins during adolescence and males are more likely than<br />
females to use tobacco products [16], we sought to understand<br />
how male adolescents respond to e cigarettes. Because earlier<br />
beliefs about a “typical smoker” are related to future use of<br />
cigarettes by adolescents [17], we also wished to explore how<br />
social images of smokers might influence willingness to try<br />
a cigarette like product. No published studies we are aware of<br />
have examined U.S. adolescent males’ views about e cigarettes.<br />
We surveyed a national sample of males ages 11e19 to explore<br />
their awareness of e cigarettes and their willingness to try them.<br />
Methods<br />
Participants<br />
Parents and their adolescent sons participated in an online,<br />
two wave survey on adolescent health described in detail by<br />
Reiter et al [18]. In brief, a survey company constructed a national<br />
panel of U.S. households by using probability sampling,<br />
a combination of list assisted, random digit dialing and address<br />
based sampling to reach cell phone only households [19]. The<br />
survey company then randomly sampled panel members who<br />
were parents with sons ages 11e17 years. In August and<br />
September 2010, parents and sons completed the online Wave 1<br />
survey. We re contacted these parents and sons in November<br />
2011 to participate in the present survey (i.e., Wave 2). Four<br />
parents indicated that their sons were 11 years old at Wave 2,<br />
suggesting that the son’s age documented in the panel profile or<br />
Wave 2 survey was off by a year. In exchange for participation,<br />
parents received 1,000 points (worth about $1) that they could<br />
later redeem for small cash payments. Households without<br />
Internet access received laptops and free Internet access. Sons<br />
received 10,000 points (worth about $10) for completing the<br />
Wave 2 survey. The Institutional Review Board at the University<br />
of North Carolina approved the study.<br />
The survey company sent e mail invitations to participate in<br />
the study to 421 parents who participated in the Wave 1 survey.<br />
Three reminder e mails were sent to parents between Waves 1<br />
and 2 to maximize participation at Wave 2. Only the Wave 2<br />
survey included items about e cigarettes. Of the 327 parents<br />
(78%) who completed the Wave 2 surveys, 228 (70%) had<br />
adolescent sons who also completed surveys. There were no<br />
J.K. Pepper et al. / Journal of Adolescent Health 52 (2013) 144 150 145<br />
differences between the 70% of sons who completed Wave 2<br />
surveys and the 30% who did not in terms of: son’s race or<br />
ethnicity; parent’s age, gender, marital status, or smoking status;<br />
or the household’s income, urbanicity, or region. Sons who<br />
completed the Wave 2 survey were less likely to have parents<br />
who attended at least some college than sons who did not<br />
complete the Wave 2 survey (56% vs. 69%, p .04).<br />
Measures<br />
Sons’ Wave 2 surveys assessed awareness of e cigarettes by<br />
asking “Have you ever heard of electronic cigarettes, often called<br />
e cigarettes?” (0 no, 1 yes). All sons then viewed a brief<br />
informational statement about e cigarettes: “E cigarettes look<br />
like regular cigarettes but they are different. They create a mist<br />
that you breathe in like smoke, but they are not made of<br />
tobacco.” We then asked “Have you ever seen someone using an<br />
e cigarette?” (0 no, 1 yes) and “Have you ever used an<br />
e cigarette?” (0 no, 1 yes).<br />
Because e cigarettes are available in a variety of flavors (plain<br />
as well as candy or fruit flavored), we assessed willingness to use<br />
an e cigarette with two items: “If one of your best friends were to<br />
offer you an e cigarette, would you try it?” and “If one of your best<br />
friends were to offer you a flavored e cigarette (chocolate, mint,<br />
apple, etc.), would you try it?” Responses of “definitely not” or<br />
“probably not” were coded as 0, and responses of “definitely yes”<br />
or “probably yes” were coded as 1. For some analyses, we grouped<br />
responses of willingness to try plain and flavored e cigarettes to<br />
create a variable for willingness to try any kind of e cigarette (0<br />
no, 1 yes), such that ‘1’ included respondents who were willing<br />
to try plain but not flavored e cigarettes, flavored but not plain<br />
e cigarettes, or both kinds of e cigarettes.<br />
We classified adolescent participants as nonsmokers (coded<br />
as 0) if they responded “never, I am not a smoker” to the question<br />
“How often do you smoke now?” We classified all other<br />
responses (“less than once a month,” “at least once a month,”“at<br />
least once a week,” and “at least once a day”) as indicating<br />
smokers (coded as 1). The item “Do you think you will smoke<br />
a cigarette in the next year?” assessed participants’ susceptibility<br />
to cigarette use. We coded responses of “definitely not” or<br />
“probably not” as 0 and responses of “definitely yes” or “probably<br />
yes” as 1.<br />
As described by the prototype/willingness model, adoles<br />
cents’ willingness to engage in risky behaviors like smoking is<br />
influenced by their self comparisons to a social image (or<br />
prototype) of the kind of person who engages in that behavior<br />
[20]. Thus, prior to asking participants about their awareness and<br />
use of e cigarettes, we evaluated their smoker prototypes [21,22].<br />
We instructed them to “Consider a typical person your age who<br />
smokes. How would you describe this person using the following<br />
characteristics?” For each of a set of eight adjectives, displayed in<br />
a random order, participants responded on a 5 point scale from<br />
“not at all” (coded as 1) to “very much” (5). We created a mean<br />
score (range 1e5) for the four items that assessed positive<br />
smoker prototypes (stylish, tough, cool, and independent;<br />
alpha .79), and a mean score for the four items that assessed<br />
negative smoker prototypes (unattractive, immature, inconsid<br />
erate, and trashy; alpha .85).<br />
Demographic characteristics included sons’ age, ethnicity<br />
(Hispanic/Latino or not Hispanic/Latino), and race (white or non<br />
white), as well as parents’ marital status, education, and smoking<br />
habits. We classified parents as having “never or rarely smoked”
146<br />
(smoked less than 100 cigarettes in their lifetimes), being<br />
“former smokers” (smoked more than 100 cigarettes in their<br />
lifetimes but not current smokers), or being “current smokers”<br />
(smoke cigarettes some days or every day). We also collected<br />
data on household characteristics: income, urbanicity (as<br />
described by the Census Bureau definition of metropolitan<br />
statistical areas, http://factfinder.census.gov/home/en/epss/<br />
glossary_r.html), and region of residence (Northeast, Midwest,<br />
South, and West). All demographic characteristics (except son’s<br />
age and son’s smoking status) used data collected at Wave 1.<br />
The complete parent and son surveys are available online at<br />
http://www.unc.edu/wntbrewer/hpv.htm.<br />
Data analyses<br />
Among sons without past use of e cigarettes, we examined<br />
bivariate correlates of awareness of and willingness to try any<br />
kind of e cigarette (plain, flavored, or both) using logistic<br />
regression. All correlates identified as statistically significant<br />
(p < .05) in bivariate analyses were included in a multivariate<br />
model. For willingness to try e cigarettes, we repeated the<br />
multivariate analysis restricted to nonsmokers. We analyzed data<br />
with SPSS version 17.0 (SPSS Inc., Chicago, IL). Statistical tests<br />
were two tailed with a critical alpha of .05.<br />
Results<br />
Participants<br />
Adolescents’ mean age was 15.1 years (Table 1). Most were<br />
nonsmokers (91%), white (80%), and lived in urban areas (84%).<br />
About half of parents reported a household income of less than<br />
$60,000 (48%). Most parents had never or rarely smoked (43%) or<br />
were former smokers (41%).<br />
Use of e cigarettes<br />
Only 2 of 228 adolescents (< 1%) had previously tried an<br />
e cigarette. Both of these participants also smoked regular<br />
cigarettes. We excluded these two adolescents from subsequent<br />
analyses.<br />
Awareness of e cigarettes<br />
The majority of adolescents (67%) had heard of e cigarettes<br />
(Table 2). In bivariate analyses, older adolescents were more<br />
likely to be aware of e cigarettes (Table 2). About three out of four<br />
participants ages 14e16 and 17e19 were aware (72% and 76%,<br />
respectively) compared to half (52%) of those 11e13 years old.<br />
Hispanic/Latino males were less likely to be aware of e cigarettes<br />
than those of other ethnicities (50% vs. 71%), and white males<br />
were more likely to be aware of e cigarettes than were other<br />
races (71% vs. 53%). Sons of parents with greater than high school<br />
education were less likely to be aware of e cigarettes (61% vs.<br />
76%), as were sons living in urban versus rural areas (64% vs.<br />
83%). Neither parents’ nor sons’ smoking status was correlated<br />
with having heard of e cigarettes.<br />
In the multivariate model of sons’ awareness, only age and<br />
Hispanic ethnicity remained statistically significant. Participants<br />
ages 14e16 were more likely to have heard of e cigarettes (OR<br />
2.12, 95% CI 1.06, 4.26) compared to participants ages 11e13, as<br />
were participants ages 17e19 (OR 2.61, 95% CI 1.21, 5.64).<br />
J.K. Pepper et al. / Journal of Adolescent Health 52 (2013) 144 150<br />
Table 1<br />
Demographic characteristics (n 228)<br />
Hispanic participants were less likely to be aware of e cigarettes<br />
(OR .44, 95% CI .21, .95).<br />
Willingness to try e cigarettes<br />
n (%)<br />
Adolescent males<br />
Age, mean (SD)<br />
Race<br />
15.1 (2.1)<br />
White 182 (80)<br />
Non-white<br />
Ethnicity<br />
46 (20)<br />
Hispanic/Latino 38 (17)<br />
Non-Hispanic/Latino<br />
Smoking status<br />
190 (83)<br />
Nonsmoker 207 (91)<br />
Smoker 21 (9)<br />
Positive smoker prototype, mean (SD) a<br />
1.7 (.8)<br />
Negative smoker prototype, mean (SD) b<br />
Will smoke in the next year<br />
3.2 (1.1)<br />
No 208 (91)<br />
Yes<br />
Tried an e-cigarette<br />
20 (9)<br />
No 226 (99)<br />
Yes<br />
Parent<br />
Age<br />
2 (1)<br />
< 45 years 140 (61)<br />
45 years<br />
Gender<br />
88 (39)<br />
Female 119 (52)<br />
Male<br />
Marital status<br />
109 (48)<br />
Married/living with partner 181 (79)<br />
Other<br />
Education<br />
47 (21)<br />
High school or less 100 (44)<br />
Some college or more<br />
Smoking status<br />
128 (56)<br />
Never or rarely smoked 97 (43)<br />
Former smoker 94 (41)<br />
Current smoker<br />
Households<br />
Annual income<br />
37 (16)<br />
< $60,000 110 (48)<br />
$60,000<br />
Urbanicity<br />
118 (52)<br />
Rural 37 (16)<br />
Urban<br />
Region of residence<br />
191 (84)<br />
Northeast 41 (18)<br />
Midwest 60 (26)<br />
South 86 (38)<br />
West 41 (18)<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough,<br />
cool, and independent. Range: not at all (coded as 1) very much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive,<br />
immature, inconsiderate, and trashy. Range: not at all (coded as 1) very much (5).<br />
A substantial minority of adolescent boys (18%) were willing<br />
to try an e cigarette if it was offered by one of their best friends:<br />
13% were willing to try a plain e cigarette, and an additional 5%<br />
were willing to try flavored e cigarettes or both kinds. The same<br />
proportion of respondents were willing to try plain e cigarettes<br />
or to try flavored e cigarettes (p .15). In bivariate analyses,<br />
adolescent males ages 17e19 were more willing to try an<br />
e cigarette compared to their 11e13 year old counterparts (29%
Table 2<br />
Correlates of awareness of e-cigarettes (n 226)<br />
Number aware of e-cigarettes/total number<br />
in category (%)<br />
vs. 11%) (Table 3). The small number of adolescent males who<br />
smoked were much more willing to try e cigarettes (74% vs. 13%)<br />
than the remaining respondents. However, sons of parents who<br />
were current smokers were less willing compared to sons of<br />
parents who had never or rarely smoked (5% vs. 22%). Sons living<br />
in households with annual incomes of $60,000 or more were also<br />
less likely to be willing to try an e cigarette (13% vs. 24%).<br />
Participants willing to try e cigarettes had less negative beliefs<br />
about the typical smoker (mean negative prototype 2.65 vs.<br />
3.35). Prior awareness of e cigarettes was not associated with<br />
willingness to use them (p .38).<br />
J.K. Pepper et al. / Journal of Adolescent Health 52 (2013) 144 150 147<br />
Bivariate Multivariate<br />
n (%) OR (95% CI) OR (95% CI)<br />
Overall<br />
Adolescent males’ characteristics<br />
Age<br />
152/226 (67)<br />
11 13 years (Ref) 33/64 (52) 1 1<br />
14 16 years 66/92 (72) 2.34 (1.22, 4.65)* 2.12 (1.06, 4.26)*<br />
17 19 years<br />
Hispanic/Latino<br />
53/70 (76) 2.93 (1.41, 6.10)** 2.61 (1.21, 5.64)*<br />
No (Ref) 133/188 (71) 1 1<br />
Yes<br />
Race<br />
19/38 (50) .41 (.20, .84)* .44 (.21, .95)*<br />
Non-white (Ref) 24/45 (53) 1 1<br />
White<br />
Smoking status<br />
128/181 (71) 2.11 (1.08, 4.12)* 1.87 (.92, 3.78)<br />
Nonsmoker (Ref) 137/207 (66) 1<br />
Smoker 15/19 (79) 1.92 (.61, 5.99)<br />
Positive smoker prototype a<br />
.78 (.55, 1.09)<br />
Negative smoker prototype b<br />
Parents’ characteristics<br />
Age<br />
.79 (.62, 1.02)<br />
< 45 years (Ref) 89/138 (64) 1<br />
45 years<br />
Gender<br />
63/88 (72) 1.39 (.78, 2.48)<br />
Female (Ref) 78/118 (66) 1<br />
Male<br />
Marital status<br />
74/108 (69) 1.12 (.64, 1.95)<br />
Other (Ref) 30/47 (64) 1<br />
Married<br />
Education<br />
122/179 (68) 1.21 (.62, 2.38)<br />
High school or less (Ref) 75/99 (76) 1 1<br />
Some college or more<br />
Smoking status<br />
77/127 (61) .49 (.28, .88)* .59 (.31, 1.10)<br />
Never or rarely smoked (Ref) 61/97 (63) 1<br />
Former smoker 63/92 (68) 1.28 (.70, 2.34)<br />
Current smoker<br />
Household characteristics<br />
Annual income<br />
28/37 (76) 1.84 (.78, 4.32)<br />
< $60,000 (Ref) 71/109 (65) 1<br />
$60,000<br />
Urbanicity<br />
81/117 (69) 1.20 (.69, 2.10)<br />
Rural (Ref) 30/36 (83) 1 1<br />
Urban<br />
Region<br />
122/190 (64) .36 (.14, .91)* .54 (.20, 1.43)<br />
Northeast (Ref) 32/41 (78) 1<br />
Midwest 41/60 (68) .61 (.24, 1.52)<br />
South 55/84 (65) .53 (.22, 1.27)<br />
West 24/41 (59) .40 (.15, 1.04)<br />
Note. Analyses excluded two adolescents who had previously used e-cigarettes. Multivariate model contains all correlates statistically significant (p < .05) in bivariate<br />
models.<br />
CI confidence interval; OR odds ratio; Ref reference category.<br />
* p < .05.<br />
** p < .01.<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough, cool, and independent. Range: not at all (coded as 1) very much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive, immature, inconsiderate, and trashy. Range: not at all (coded as 1) very much (5).<br />
Only sons’ smoking status remained statistically significant in<br />
the multivariate model (OR 10.25, 95% CI 2.88, 36.46). However,<br />
when we excluded sons who smoked (n 19) from the model,<br />
only endorsement of negative smoker prototypes was statisti<br />
cally significant. That is, willingness to try e cigarettes was<br />
associated with less negative beliefs about the typical smoker<br />
(mean negative prototype 2.83 vs. mean 3.39, OR .58, 95% CI .43,<br />
.79). When negative beliefs were dichotomized using a median<br />
split, the association held. More adolescents below or at the<br />
median of negative beliefs were willing to try an e cigarette<br />
compared to adolescents above the median (24% vs. 12%, p .02).
148<br />
Table 3<br />
Correlates of willingness to try an e-cigarette (plain or flavored) (n 226)<br />
Discussion<br />
Number willing to try an e-cigarette/total number<br />
in category (%)<br />
Although few adolescent males in our national sample had<br />
tried e cigarettes, around two thirds were aware of them. This<br />
figure is much higher than expected, given that only 32% of<br />
adults in a national sample were aware of e cigarettes as of 2010<br />
[5]. The high rate of awareness in our sample may reflect the<br />
increasing popularity of and media attention given to the<br />
J.K. Pepper et al. / Journal of Adolescent Health 52 (2013) 144 150<br />
Bivariate Multivariate<br />
n (%) OR (95% CI) OR (95% CI)<br />
Overall<br />
Adolescent males’ characteristics<br />
Age<br />
41/226 (18)<br />
11 13 years (Ref) 7/64 (11) 1 1<br />
14 16 years 14/92 (15) 1.46 (.55, 3.85) 1.16 (.42, 3.16)<br />
17 19 years<br />
Hispanic/Latino<br />
20/70 (29) 3.26 (1.27, 8.35)* 1.46 (.49, 4.32)<br />
No (Ref) 34/188 (18) 1<br />
Yes<br />
Race<br />
7/38 (18) 1.02 (.42, 2.52)<br />
Non-white (Ref) 8/45 (18) 1<br />
White<br />
Smoking status<br />
33/181 (18) 1.03 (.44, 2.42)<br />
Nonsmoker (Ref) 27/207 (13) 1 1<br />
Smoker 14/19 (74) 18.67 (6.22, 55.98)*** 10.25 (2.88, 36.46)***<br />
Positive smoker prototype a<br />
1.18 (.79, 1.77)<br />
Negative smoker prototype b<br />
Awareness of e-cigarettes<br />
.58 (.43, .79)** .74 (.52, 1.05)<br />
Not aware 11/74 (15) 1<br />
Aware<br />
Parents’ characteristics<br />
Age<br />
30/152 (20) 1.41 (.66, 3)<br />
< 45 years (Ref) 26/138 (19) 1<br />
45 years<br />
Gender<br />
15/88 (17) .89 (.44, 1.78)<br />
Female (Ref) 23/118 (19) 1<br />
Male<br />
Marital status<br />
18/108 (17) .83 (.42, 1.63)<br />
Other (Ref) 12/47 (26) 1<br />
Married<br />
Education<br />
29/179 (16) .56 (.26, 1.21)<br />
High school or less (Ref) 20/99 (20) 1<br />
Some college or more<br />
Smoking status<br />
21/127 (17) .78 (.40, 1.54)<br />
Never or rarely smoked (Ref) 21/97 (22) 1 1<br />
Former smoker 18/92 (20) .88 (.43, 1.78) .85 (.38, 1.89)<br />
Current smoker<br />
Household characteristics<br />
Annual income<br />
2/37 (5) .21 (.05, .93)* .28 (.06, 1.38)<br />
< $60,000 (Ref) 26/109 (24) 1 1<br />
$60,000<br />
Urbanicity<br />
15/117 (13) .47 (.23, .94)* .72 (.33, 1.60)<br />
Rural (Ref) 6/36 (17) 1<br />
Urban<br />
Region<br />
35/190 (18) 1.13 (.44, 2.92)<br />
Northeast (Ref) 6/41 (15) 1<br />
Midwest 12/60 (20) 1.46 (.50, 4.26)<br />
South 17/84 (20) 1.48 (.54, 4.09)<br />
West 6/41 (15) 1 (.29, 3.40)<br />
Note. Analyses excluded two adolescents who had previously used e-cigarettes. Multivariate model contains all correlates significant (p < .05) in bivariate models.<br />
CI confidence interval; OR odds ratio; Ref reference category.<br />
* p < .05.<br />
** p < .01.<br />
*** p < .001.<br />
a Mean rating of the typical smoker on these characteristics: stylish, tough, cool, and independent. Range: not at all (coded as 1) very much (5).<br />
b Mean rating of the typical smoker on these characteristics: unattractive, immature, inconsiderate, and trashy. Range: not at all (coded as 1) very much (5).<br />
product [5,7,8] or to the rise in e cigarette promotion in the past<br />
2 years [6,16]. For example, e cigarettes are advertised exten<br />
sively online, and disposable e cigarettes are now sold in many<br />
convenience stores and gas stations. Our findings may also reflect<br />
higher awareness among adolescents than adults.<br />
Within our sample, older adolescents were more likely to be<br />
aware of e cigarettes than younger adolescents, while Hispanic<br />
adolescents were less likely to be aware compared to their
non Hispanic counterparts. This pattern could reflect greater<br />
awareness of or exposure to all nicotine and tobacco products.<br />
Cigarette smoking rates increase with age throughout adoles<br />
cence, and Hispanic young adults are less likely to smoke than<br />
white young adults [16].<br />
Consistent with findings on adolescent males’ susceptibility<br />
to regular cigarettes, nearly 1 in 5 adolescent males in our study<br />
were willing to try either a plain or flavored e cigarette if one of<br />
their best friends offered it; willingness to try plain versus<br />
flavored varieties did not differ. This preliminary finding suggests<br />
that, at present, candy or fruit flavors do not increase the<br />
attractiveness of e cigarettes to adolescents. However, before<br />
their ban by the FDA in 2009 [23], flavored non electronic ciga<br />
rettes were particularly popular among youth smokers<br />
compared to adult smokers, in part due to youth targeted<br />
advertising [24]. Future marketing of flavored e cigarettes<br />
toward young people could increase the appeal of the product<br />
relative to unflavored e cigarettes.<br />
Being a smoker was the strongest predictor of willingness to<br />
try an e cigarette. Even after controlling for other statistically<br />
significant correlates, the odds of a smoker being willing to try an<br />
e cigarette were 10 times the odds of a nonsmoker. This pattern<br />
is consistent with survey data showing that most adult e cigarette<br />
users are or were smokers [5]. Because adolescent smokers<br />
exhibit more sensation seeking than nonsmokers [25], smokers<br />
may be more willing to try new, potentially risky behaviors, such<br />
as e cigarette use, than their nonsmoking counterparts. Alterna<br />
tively, both smoking and nonsmoking adolescents might view<br />
e cigarettes as similar, or even equivalent, to regular cigarettes.<br />
Thus, if they have already used one product, they are willing to try<br />
the other. Similar to adult smokers, young smokers may also be<br />
attracted to e cigarettes because they view them as a tool to quit<br />
smoking, an option for using nicotine in places where smoking is<br />
banned, or a less unpleasant version of regular cigarettes [9,26].<br />
When we removed smokers from analyses, the only predictor<br />
of willingness to try an e cigarette in multivariate analyses was<br />
smoker prototype. Specifically, having more negative beliefs<br />
about the typical smoker was associated with lower willingness.<br />
According to the prototype/willingness model, risky behavior,<br />
particularly among adolescents, is driven by a combination of<br />
reasoned cognitions and social reactions [20]. One assumption of<br />
the model is that adolescents associate risk behaviors with<br />
specific social images (also called prototypes) of a person who<br />
engages in that behavior. Comparing themselves to that social<br />
image influences their willingness and behavior. Thus, associ<br />
ating oneself with positive images of smokers should predict<br />
future smoking behavior, as has been found in longitudinal<br />
studies [17]. Our findings are consistent with the prototype/<br />
willingness model. Believing that smokers were unattractive,<br />
immature, inconsiderate, or trashy was associated with reduced<br />
interest in trying e cigarettes, possibly because respondents<br />
viewed e cigarettes as similardor even the samedas regular<br />
cigarettes. Thus, they were less willing to try a product that they<br />
associated with these negative prototypes. In line with the<br />
prototype/willingness model and given that teenagers are<br />
already influenced by images of smoking in the media [27],<br />
our findings suggest that presenting negative portrayals of<br />
smokers could potentially discourage nonsmokers from trying<br />
e cigarettes.<br />
Although willingness to use e cigarettes among non<br />
smokers was lower than among smokers, even minimal<br />
interest among this population is concerning, given that most<br />
J.K. Pepper et al. / Journal of Adolescent Health 52 (2013) 144 150 149<br />
adolescent males are nonsmokers [16]. Furthermore, nicotine<br />
dependence can start to occur within weeks of occasional<br />
tobacco use [28], so even brief experimentation with nicotine<br />
containing e cigarettes could bolster adolescents’ interest in<br />
using other tobacco products.<br />
Because this study was cross sectional, we were not able to<br />
assess whether attitudes about smokers influenced willingness<br />
to try e cigarettes or vice versa. Moreover, we could not address<br />
whether participants’ attitudes and behaviors changed over<br />
time. Another limitation is that we asked participants about their<br />
willingness to try “an e cigarette” and “a flavored e cigarette”<br />
without specifying that the former question referred to regular,<br />
unflavored e cigarettes. We also did not ask e cigarette users<br />
about the duration or frequency of their use or whether they<br />
began using e cigarettes prior to initiating smoking regular<br />
cigarettes. However, the small number of respondents (n 2) in<br />
this group and our study’s cross sectional design would prevent<br />
us from examining the “gateway” hypothesis in any case.<br />
Participants self reported their smoking and e cigarette use, but<br />
adolescents’ self reported use of regular cigarettes is largely<br />
consistent with the results of serum cotinine testing [29].<br />
Although we examined predictors of self reported intention,<br />
rather than behavior, this choice is appropriate for studying early<br />
adoption of new behaviors [30]. The study benefited from the use<br />
of a national sample, which increases our confidence that the<br />
findings may generalize to other U.S. adolescent males.<br />
Should additional studies replicate our findings of high level<br />
of awareness and moderate willingness to try e cigarettes among<br />
adolescent males, the FDA should evaluate devoting regulatory<br />
resources toward preventing youth from initiating use. Specifi<br />
cally, we believe that the FDA should consider implementing<br />
a ban on the sale of e cigarettes to minors and monitoring<br />
advertisements, particularly those for flavored e cigarettes, to<br />
ensure that they do not target youth. As e cigarette research<br />
continues, it will be important to track the number of youth who<br />
initiate e cigarette use as a precursor to smoking.<br />
References<br />
[1] U.S. Food and Drug Administration. Evaluation of e-cigarettes. 2009.<br />
Available at: http://www.fda.gov/downloads/Drugs/ScienceResearch/<br />
UCM173250.pdf.<br />
[2] Laugesen M. Safety report on the Ruyan e-cigarette cartridge and inhaled<br />
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[3] U.S. Food and Drug Administration. Electronic cigarettes. News & events.<br />
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ucm172906.htm.<br />
[4] U.S. Food and Drug Administration. Regulation of e-cigarettes and other<br />
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PublicHealthFocus/ucm252360.htm.<br />
[5] Regan AK, Promoff G, Dube SR, et al. Electronic nicotine delivery systems:<br />
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online ahead of print].<br />
[6] Ayers JW, Ribisl KM, Brownstein JS. Tracking the rise in popularity of<br />
electronic nicotine delivery systems (electronic cigarettes) using search<br />
query surveillance. Am J Prev Med 2011;40:448 53.<br />
[7] Tierney J. A tool to quit smoking has some unlikely critics. New York Times;<br />
2011 Nov 7.<br />
[8] Mishori R. E-cigarettes: Can they help you quit? Parade Magazine; 2009<br />
July 12.<br />
[9] Etter JF, Bullen C. Electronic cigarette: users profile, utilization, satisfaction<br />
and perceived efficacy. Addiction 2011;106:2017 28.<br />
[10] Etter JF. Electronic cigarettes: A survey of users. BMC Public Health 2010;<br />
10:231.<br />
[11] Foulds J, Veldheer S, Berg A. Electronic cigarettes (e-cigs): Views of<br />
aficionados and clinical/public health perspectives. Int J Clin Pract 2011;65:<br />
1037 42.
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[12] Bell K, Keane H. Nicotine control: E-cigarettes, smoking and addiction. Int J<br />
Drug Policy 2012;23:242e7.<br />
[13] Borland R. Electronic cigarettes as a method of tobacco control. BMJ 2011;<br />
343:d6269.<br />
[14] Cobb NK, Byron MJ, Abrams DB, et al. Novel nicotine delivery systems and<br />
public health: The rise of the "e-cigarette." Am J Public Health 2010;100:<br />
2340e2.<br />
[15] Riker CA, Lee K, Darville A, et al. E-cigarettes: Promise or peril? Nurs Clin N<br />
Am 2012;47:159e71.<br />
[16] U.S. Department of Health and Human Services. Preventing tobacco use<br />
among youth and young adults: A report of the Surgeon General. Atlanta,<br />
GA: Centers for Disease Control and Prevention, National Center for<br />
Chronic Disease Prevention and Health Promotion, Office on Smoking and<br />
Health; 2012.<br />
[17] Aloise-Young PA, Hennigan KM, Graham JW. Role of the self-image and<br />
smoker stereotype in smoking onset during early adolescence: A longitudinal<br />
study. Health Psychol 1996;15:494e7.<br />
[18] Reiter PL, McRee AL, Kadis JA, et al. HPV vaccine and adolescent males.<br />
Vaccine 2011;29:5595e602.<br />
[19] Dennis JM. Description of within-panel survey sampling methodology:<br />
The Knowledge Networks approach. 2009. Available at: http://www.<br />
knowledgenetworks.com/ganp/docs/KN-Within-Panel-Survey-Sampling-<br />
Methodology.pdf.<br />
[20] Gibbons FX, Gerrard M, Lane DJ. A social reaction model of adolescent<br />
health risk. In: Suls J, Wallston KA, editors. Social psychological foundations<br />
of health and illness. Malden, MA: Blackwell Publishing Ltd.;<br />
2003:107e36.<br />
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[21] McCool JP, Cameron L, Petrie K. Stereotyping the smoker: Adolescents’<br />
appraisals of smokers in film. Tob Control 2004;13:308e14.<br />
[22] McCool J, Cameron LD, Robinson E. Do parents have any influence over<br />
how young people appraise tobacco images in the media? J Adolesc Health<br />
2011;48:170e5.<br />
[23] U.S. Food and Drug Administration. Flavored tobacco. 2011. Available at:<br />
http://www.fda.gov/TobaccoProducts/ProtectingKidsfromTobacco/Flavored<br />
Tobacco/default.htm.<br />
[24] Klein SM, Giovino GA, Barker DC, et al. Use of flavored cigarettes among<br />
older adolescent and adult smokers: United States, 2004e2005. Nicotine<br />
Tob Res 2008;10:1209e14.<br />
[25] Frankenberger KD. Adolescent egocentrism: A comparison among adolescents<br />
and adults. J Adolescence 2000;23:343e54.<br />
[26] McQueen A, Tower S, Sumner W. Interviews with "vapers": Implications<br />
for future research with electronic cigarettes. Nicotine Tob Res 2011;13:<br />
860e7.<br />
[27] McCool JP, Cameron LD, Petrie KJ. The influence of smoking imagery on the<br />
smoking intentions of young people: Testing a media interpretation model.<br />
J Adolesc Health 2005;36:475e85.<br />
[28] DiFranza JR, Rigotti NA, McNeill AD, et al. Initial symptoms of nicotine<br />
dependence in adolescents. Tob Control 2000;9:313e9.<br />
[29] Caraballo RS, Giovino GA, Pechacek TF. Self-reported cigarette smoking<br />
versus serum cotinine among U.S. adolescents. Nicotine Tob Res 2004;6:<br />
19e25.<br />
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669e79.
Nachschlagewerk zum Thema E-Zigaretten<br />
55 Examination of exhaled vapor from e-cigarettes
Gutachten Nr. 12-09556-4/gch<br />
Diese Version ersetzt die Version 12-09556-3<br />
Altenberge, 01.02.2012<br />
Prüfung des ausgeatmeten Dampfes von e-Zigaretten<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
56 Impact of an Electronic Cigarette on Smoking<br />
Reduction
Int. J. Environ. Res. Public Health 2013, 10, 446-461; doi:10.3390/ijerph10020446<br />
Article<br />
International Journal of<br />
Environmental Research and<br />
Public Health<br />
ISSN 16604-601<br />
www.mdpi.com/journal/ijerph<br />
Impact of an Electronic Cigarette on Smoking Reduction and<br />
Cessation in Schizophrenic Smokers: A Prospective 12-Month<br />
Pilot Study<br />
Pasquale Caponnetto 1,2,3, *, Roberta Auditore 1 , Cristina Russo 1,2,3 , Giorgio Carlo Cappello 4<br />
and Riccardo Polosa 2,3<br />
1<br />
CTA-Villa Chiara Psychiatric Rehabilitation Clinic and Research, Mascalucia (Catania) 95030,<br />
Italy; E-Mails: robertaauditore@virgilio.it (R.A.); kristina_russo@yahoo.com (C.R.)<br />
2<br />
Smoking Prevention/Cessation Centre, A.O.U, Policlinico-V. Emanuele, University of Catania,<br />
Catania 95100, Italy; E-Mail: polosa@unict.it<br />
3<br />
Institute of Internal Medicine, G. Rodolico Hospital, A.O.U, Policlinico-V. Emanuele, University of<br />
Catania, Catania 95100, Italy<br />
4<br />
National Strategic Planning & Analysis Research Center, Mississippi State University, Mississippi<br />
State, MS 39762, USA; E-Mail: carlocappello@live.it<br />
* Author to whom correspondence should be addressed; E-Mail: p.caponnetto@unict.it;<br />
Tel.: +390-957-910-366; Fax: +390-957-435-083.<br />
Received: 26 November 2012; in revised form: 9 January 2013 / Accepted: 10 January 2013 /<br />
Published: 28 January 2013<br />
OPEN ACCESS<br />
Abstract: Background: Cigarette smoking is a tough addiction to break. This dependence<br />
is the most common dual diagnosis for individuals with schizophrenia. Currently three<br />
effective drugs are approved for smoking cessation: nicotine replacement therapy (NRT),<br />
varenicline and bupropion. However, some serious side effects of varenicline have been<br />
reported, including depression, suicidal thoughts, and suicide. The use of bupropion also has<br />
side effects. It should not be used by people who have epilepsy or any condition that lowers the<br />
seizure threshold, nor by people who take a specific class of drugs called monoamine oxidase<br />
inhibitors. Hence, there are pharmacodynamic reason to believe they could precipitate or<br />
exacerbate psychosis. For its capacity to deliver nicotine and provide a coping mechanism<br />
for conditioned smoking cues by replacing some of the rituals associated with smoking<br />
gestures, electronic-cigarettes may reduce nicotine withdrawal symptoms without serious<br />
side effects. Our recent work with ECs in healthy smokers not intending to quit consistently<br />
show surprisingly high success rates. We hypothesised that these positive findings could be
Int. J. Environ. Res. Public Health 2013, 10 447<br />
replicated in difficult patients with schizophrenia This tool may help smokers with<br />
schizophrenia remain abstinent during their quitting attempts or to reduce cigarette<br />
consumption. Efficacy and safety of these devices in long-term smoking cessation and/or<br />
smoking reduction studies have never been investigated for this special population.<br />
Methods: In this study we monitored possible modifications in smoking habits of<br />
14 smokers (not intending to quit) with schizophrenia experimenting with the “Categoria”<br />
e-Cigarette with a focus on smoking reduction and smoking abstinence. Study participants<br />
were invited to attend six study visits: at baseline, week-4, week-8, week-12 week-24 and<br />
week 52. Product use, number of cigarettes smoked, carbon monoxide in exhaled breath<br />
(eCO) and positive and negative symptoms of schizophrenia levels were measured at each<br />
visit. Smoking reduction and abstinence rates were calculated. Adverse events were also<br />
reviewed. Results: Sustained 50% reduction in the number of cig/day at week-52 was<br />
shown in 7/14 (50%) participants; their median of 30 cig/day decreasing significantly to<br />
15 cig/day (p = 0.018). Sustained smoking abstinence at week-52 was observed in 2/14<br />
(14.3%) participants. Combined sustained 50% reduction and smoking abstinence was<br />
shown in 9/14 (64.3%) participants. Nausea was observed in 2/14 (14.4%) of participants,<br />
throat irritation in 2/14 (14.4%) of participants, headache in 2/14 (14.4%) of participants ,<br />
and dry cough in 4/14 (28.6%) of participants. However, these adverse events diminished<br />
substantially by week-24. Overall, one to two cartridges/day were used throughout the<br />
study. Positive and negative symptoms of schizophrenia are not increased after smoking<br />
reduction/cessation in patients using e-cigarettes. Conclusions: We have shown for the first<br />
time that the use of e-cigarette substantially decreased cigarette consumption without<br />
causing significant side effects in chronic schizophrenic patients who smoke not intending<br />
to quit. This was achieved without negative impacts on the symptoms of schizophrenia as<br />
assessed by SAPS and SANS symptoms scales.<br />
Keywords: smoking cessation; smoking reduction; electronic cigarette; electronic nicotine<br />
delivery device; schizophrenia<br />
1. Introduction<br />
Schizophrenia is a mental disorder characterized by a breakdown of thought processes and by poor<br />
emotional responsiveness. It is well established in studies across several countries that tobacco<br />
smoking is more prevalent among schizophrenic patients than the general population [1]. For example,<br />
in the US, 80% or more of schizophrenics smoke, compared to approximately 20% of the general<br />
population [2]. Many social, psychologic and biologic explanations have been proposed, but today<br />
research focuses on neurobiological action of nicotine and its pharmacodynamic interactions.<br />
For example, it was hypothesized that schizophrenic patients smoke to reduce symptoms and/or to<br />
mitigate the negative effects of neuroleptic therapy [3], that smoking may contribute to development of<br />
the disorder by altering neuro-chemical systems in the brain, [4] and that both conditions could arise<br />
from a common genetic vulnerability [1]. Smoking is often accepted as a customary social activity in
Int. J. Environ. Res. Public Health 2013, 10 448<br />
many psychiatric treatment facilities, sometimes despite smoking bans and schizophrenic patients are<br />
seldom encouraged to quit smoking [5]. As a consequence, smoking related morbidity and mortality<br />
are particularly high in patients with schizophrenia [6].<br />
As the risk of serious disease diminishes rapidly after quitting and life-long abstinence is known to<br />
reduce the risk of lung cancer, heart disease, strokes, chronic lung disease and other cancers [7,8],<br />
smoking cessation in these patients is mandatory.<br />
Although there is little doubt that currently-marketed smoking cessation products increase the<br />
chance of committed smokers to stop smoking [9], they are not particularly effective in schizophrenic<br />
patients who smoke [5,10,11]. This scenario is further complicated by the belief that quitting smoking<br />
will worsen psychiatric symptoms, or that these patients have little or no interest in quitting. Moreover,<br />
the prescribing information for bupropion and varenicline, two important first-line medications for<br />
nicotine dependence, carry a “black-box” warning highlighting an increased risk of psychiatric<br />
symptoms and suicidal ideation in patients reporting any history of psychiatric illness [12]. A more<br />
effective approach to smoking cessation interventions in schizophrenic patients who smoke thus is an<br />
important unmet need. The electronic-cigarette (Figure 1) is a battery-powered electronic nicotine<br />
delivery device (ENDD) resembling a cigarette designed for the purpose of nicotine delivery, where no<br />
tobacco or combustion is necessary for its operation [13]. Consequently, this product may be<br />
considered as a lower risk substitute for factory-made cigarettes. In addition, people report buying<br />
them to help quit smoking, to reduce cigarette consumption and to relieve tobacco withdrawal<br />
symptoms due to workplace smoking restrictions [14]. Besides delivering nicotine, e-cigarettes may<br />
also provide a coping mechanism for conditioned smoking cues by replacing some of the rituals<br />
associated with smoking gestures. For this reason, e-cigarettes may help smokers to remain abstinent<br />
during their quit attempts or to reduce cigarette consumption. A recent internet survey on the<br />
satisfaction of e-cigarette use has reported that the device helped in smoking abstinence and improved<br />
smoking-related symptoms [15], but under acute experimental conditions, two marketed electronic<br />
cigarette brands suppressed tobacco abstinence symptom ratings without leading to measurable levels<br />
of nicotine or carbon monoxide (CO) in exhaled breath [16].<br />
Figure 1. The e-cigarette is a battery-powered electronic nicotine delivery device (ENDD)<br />
designed for the purpose of providing inhaled doses of nicotine by way of a vaporized<br />
solution to the respiratory system.
Int. J. Environ. Res. Public Health 2013, 10 449<br />
Our recent work with ECs in healthy smokers not intending to quit consistently show surprisingly<br />
high success rates [17,18]. We hypothesised that these positive findings could be replicated in difficult<br />
patients with schizophrenia. With this in mind, we designed a prospective proof-of-concept study to<br />
monitor possible modifications in the smoking habits of a group of well characterized regular smokers<br />
with schizophrenia experimenting a popular brand of e-cigarette (“Categoria”, Arbi Group Srl, Italy)<br />
focusing on smoking reduction and smoking abstinence. We also measured positive and negative<br />
symptoms of schizophrenia and possible adverse events.<br />
2. Experimental Section<br />
2.1. Participants<br />
Cronic schizophrenic in-patients, who smoked ≥20 factory-made cigarettes per day (cig/day) for at<br />
least the past 10 years, able to understand the assessment procedures, and to provide written informed<br />
consent were recruited from the “C.T.A, Villa Chiara-Psichiatrica Riabilitativa e Ricerca”, Mascalucia<br />
(Catania, Italy). All patients fulfilled ICD-10 [19] and DSM-IV-TR [20] criteria for schizophrenia.<br />
The diagnosis was made by a psychiatrist and a clinical psychologist, based on definitions of these<br />
diseases in ICD-10 and DSM-IV-TR, and using a structured clinical interview [21] the Structured<br />
Clinical Interview for DSM IV Axis I Disorders (SCID-I).<br />
None of the participants reported a history of alcohol and illicit drug use. We also excluded subjects<br />
who reported recent myocardial infarction, angina pectoris, high blood pressure (BP > 140 mmHg<br />
systolic and/or 90 mmHg diastolic), diabetes mellitus, severe allergies, poorly controlled asthma or<br />
other airway diseases. The study was approved by the local institutional ethics committee and<br />
participants gave written informed consent prior to participation in the study.<br />
2.2. Study Design and Baseline Measures<br />
Eligible participants were invited to use an electronic-cigarette (“Categoria” e-Cigarette, Arbi<br />
Group Srl, Milano, Italy) and were followed up prospectively for 12 months. They attended a total of<br />
six study visits at our smoking cessation clinic (Smoking Cessation/Research Centre, University of<br />
Catania, Italy): a baseline visit and five follow-up visits, (at week-4, week-8, week-12, week-24 and<br />
week 52) (Figure 2).<br />
At baseline (study visit 1), basic demographic and a detailed smoking history were taken and<br />
individual pack-years (pack/yrs) calculated together with scoring of their level of nicotine dependence<br />
by means of Fagerstrom Test of Nicotine Dependence (FTND) questionnaire [22].<br />
Positive and negative symptoms of schizophrenia were assessed with the Scale for Assessment of<br />
Negative Symptoms (SANS) [23] and the Scale for Assessment of Positive Symptoms (SAPS) [24].<br />
Additionally, levels of carbon monoxide in exhaled breath (eCO) were measured using a portable<br />
device (Micro CO, Micro Medical Ltd, Kent, UK). Participants were given a free e-cigarette kit<br />
containing two rechargeable batteries, a charger, and two atomizers and instructed on how to charge,<br />
activate and use the e-cigarette. Key troubleshooting issues were addressed and phone numbers were<br />
supplied for both technical and medical assistance. A full 4-weeks supply of 7.4 mg nicotine cartridges<br />
(“Original” cartridges, Arbi Group Srl, Milano, Italy) was also provided and participants were trained
Int. J. Environ. Res. Public Health 2013, 10 450<br />
on how to load them onto the e-cigarette’s atomizer. Random checks confirmed that the nicotine<br />
content per cartridge was 7.25 mg. Detailed toxicology and nicotine content analyses of “Original”<br />
cartridges had been carried in a laboratory certified by the Italian Institute of Health [25].<br />
Figure 2. Number of patients recruited and flow of patients within the study.<br />
Participants were permitted to use the study product ad libitum throughout the day (up to a<br />
maximum of 4 cartridges per day, as recommended by the manufacturer) in the anticipation of<br />
reducing the number of cig/day smoked, and to fill out a 4-weeks’ study diary recording product use,<br />
number of any tobacco cigarettes smoked, and adverse events.<br />
Participants were invited to came back at week-4 (study visit 2), week-8 (study visit 3), and week-12<br />
(visit 4), (a) to receive further free supply of nicotine cartridges together with the study diaries for the<br />
residual study periods, (b) to record their eCO levels, and (c) to give back completed study diaries and<br />
unused study products.<br />
Study participants attended two final follow-up visits at week-24 (study visit 5) and at week-52<br />
(study visit 6) to report product use (cartridges/day) and the number of any tobacco cigarettes smoked<br />
(from which smoking reduction and smoking abstinence could be calculated), to re-check eCO levels<br />
and to assess positive and negative symptoms of schizophrenia by the Scale for Assessment of
Int. J. Environ. Res. Public Health 2013, 10 451<br />
Negative Symptoms (SANS) and the Scale for Assessment of Positive Symptoms (SAPS). The SAPS<br />
consists of 31 items tapping four symptom domains and a global rating of positive symptoms<br />
(range 01–55). Higher scores indicate more positive symptoms. SAPS items are rated on a 6-point<br />
scale (0 = none, 5 = severe). The SANS is composed of 19 items measuring five domains as well as the<br />
global ratings of negative symptoms (range 0–5). Higher scores indicate more negative symptoms.<br />
SANS items are rated on a 6-point scale (0 = none, 5 = severe). Adverse events were obtained from<br />
their study diaries.<br />
Given the observational nature of this study, no emphasis on encouragement, motivation and reward<br />
for the smoking cessation effort were provided since this study was intended to monitor the case of a<br />
smoker with schizophrenia (unwilling to quit) trying out an unconventional nicotine delivery device in<br />
a real life setting.<br />
2.3. Study Outcome Measures<br />
The primary efficacy measure was sustained 50% reduction in the number of cig/day at week-52<br />
from baseline (reducers) [26]; defined as sustained self-reported 50% reduction in the number of<br />
cig/day compared to baseline for the 30 days period prior to week-52 study visit (eCO levels were<br />
measured to objectively verify smoking status and to document a reduction compared to baseline).<br />
An additional secondary efficacy measure of the study was sustained smoking abstinence at week-52<br />
(quitters); defined as complete self-reported abstinence from tobacco smoking (not even a puff) for the<br />
30 days period prior to week-52 study visit (eCO levels were measured to objectively verify smoking<br />
status with an eCO concentration of ≤10 ppm). Those smokers who failed to meet the above criteria at<br />
the final week-52 follow-up visit (study visit 6) were categorized as reduction/cessation failures<br />
(failures).<br />
2.4. Statistical Analyses<br />
This was an exploratory study with opportunistic sampling and sample size calculations were not<br />
performed. Primary and secondary outcome measures were computed by including all enrolled<br />
participants. The changes from baseline (study visit 1) in number of cig/day and in eCO levels were<br />
compared with data recorded at subsequent follow-up visits using Wilcoxon Signed rank test as these<br />
methods were non-parametric. Parametric and non-parametric models were expressed as mean (±SD)<br />
and median [interquartile range (IQR)], respectively. Correlations were calculated using Spearman’s<br />
Rho Correlation. Statistical tests were 2-tailed, and p values of
Int. J. Environ. Res. Public Health 2013, 10 452<br />
3. Results and Discussion<br />
3.1. Participant Characteristics<br />
A total of 14 (M 6; F 8; mean (±SD) age of 44.6 (±12.5) years) chronic schizophrenic inpatients<br />
who smoked [mean (±SD) pack/years of 28.8 (±12.9)] consented to participate and were included in<br />
the study (Table 1). All fourteen patients completed the study.<br />
3.2. Outcome Measures<br />
Subjects eligible for<br />
inclusion<br />
(n = 14)<br />
Table 1. Patient demographics.<br />
Parameter Mean (±SD) *<br />
Age 44.6 (±12.5)<br />
Sex 6M; 8F<br />
Pack Years 28.8 (±12.9)<br />
FTND 7 (5, 10) *<br />
SAPS 15 (9.5, 22) *<br />
SANS 44 (26.75, 53.5) *<br />
Cigarettes/day 30 (20, 35) *<br />
eCO 29 (23.5, 35.2) *<br />
* Non-parametric data expressed as median (IQR).<br />
Abbreviations: SD: Standard Deviation; M: Male; F: Female;<br />
FTND: Fagerstrom Test of Nicotine Dependence; eCO:<br />
exhaled carbon monoxide; IQR: interquartile range; SAPS:<br />
Scale for Assessment of Positive Symptoms; SANS: Scale for<br />
Assessment of Negative Symptoms.<br />
Participants’ smoking status and positive and negative symptoms of schizophrenia at baseline and at<br />
52-week is shown on Table 2. Sustained 50% reduction in the number of cig/day at week-52 was<br />
shown in 7/14 (50%) participants, with a median of 30 cig/day (IQR 30, 60) decreasing significantly to<br />
15 cig/day (IQR 10, 20) (p = 0.018). There were 2/14 (14.3%) quitters. Overall, combined sustained<br />
50% reduction and smoking abstinence was shown in 9/14 (64.3%) participants, with a median of<br />
30 cig/day (IQR 25, 45) decreasing significantly to 12 cig/day (IQR 4.5, 17.5) (p = 0.007). Details of<br />
mean cigarette use are shown in Figure 3a. In the present study, the smoking reduction with<br />
“Categoria” e-Cigarette use was associated to a substantial decrease in the level of eCO (Figure 3b).<br />
3.3. Product Use<br />
Details of mean cartridge use throughout the study is shown in Figure 3c. The reported number of<br />
cartridges/day used by our study participants was dissimilar, ranging from a maximum of four<br />
cartridges/day (as per manufacturer’s recommendation) to a minimum of 0 cartridges/day (“zero” was<br />
recorded in the study diary, when the same cartridge was used for more than 24 hours). For the whole<br />
group (n = 14), a mean (±SD) 1.1 (±0.7) cartridges/day was used throughout the study. The number of<br />
cartridges/day used was slightly higher when these summary statistics were computed with the<br />
exclusion of the six study failures; the value increasing to a mean (±SD) of 1.3 (±0.5) cartridges/day.
Int. J. Environ. Res. Public Health 2013, 10 453<br />
Correlation between the number of cartridges/day and smoking reduction in those participants with<br />
sustained 50% reduction in smoking was non-significant (Rho-0.809; p = 0.28). The correlation<br />
between the number of cartridges/day, and combined sustained 50% reduction and smoking abstinence<br />
was non-significant (Rho-0.322; p = 0.398).<br />
Table 2. Subject parameter outcomes and psychopathological trends following 52 weeks of<br />
electronic cigarette use.<br />
Parameter AT BASELINE<br />
AT 52-Weeks<br />
Post E-Cigarette<br />
p value ‡<br />
Sustained 50% (excluding quitters) reduction in cigarette smoking (n = 7)<br />
Age 42.4 (±8.3) †<br />
Sex 3M; 4F<br />
Pack Years 34.7 (±12.1) †<br />
Cigarettes/day 30 (30, 60) * 15 (10, 20) * 0.018<br />
eCO 32 (22, 39) * 17 (11, 20) * 0.028<br />
SAPS 15 (12, 23) * 12 (10, 25) * 0.147<br />
SANS 51 (41, 63) * 45 (40, 48) * 0.351<br />
Sustained 100% (quitters) reduction in cigarette smoking (n = 2)<br />
Age 51(±7.1) †<br />
Sex 1M; 1F<br />
Pack Years 20.25 (±0.0) †<br />
Cigarettes/day 20 (15, 15) * 0 (0, 0) * 0.157<br />
eCO 24 (15.7, 20. 3) * 2 (1.5, 1.5) * 0.180<br />
SAPS 13 (3, 16.5) * 14 (4.5, 16.5) * 0.317<br />
SANS 27.5 (7.5, 33.8) * 26.5 (7.5, 32.2) * 0.317<br />
Sustained >50% (including quitters) reduction in cigarette smoking (n = 9)<br />
Age 44.3 (±8.5) †<br />
Sex 4M; 5F<br />
Pack Years 31.5 (±12.2) †<br />
Cigarettes/day 30 (25, 45) * 12 (4.5, 17.5) * 0.007<br />
eCO 22 (15, 32) * 12 (6, 15.5) * 0.021<br />
SAPS 15 (10, 22.5) * 12 (10, 22.5) * 0.203<br />
SANS 48 (35.5, 62) * 45 (39, 27.5) * 0.260<br />
Smoking Failure (
Int. J. Environ. Res. Public Health 2013, 10 454<br />
Figure 3. Changes in the mean (±SD) cigarette, eCO levels and cartridge use throughout the study.<br />
(a)<br />
(b)<br />
(c)<br />
Mean Cigarettes/day<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
Week 0 Week 4 Week 8 Week 12 Week 24 Week 52<br />
Time<br />
>50% reduction<br />
Quitters<br />
Failures
Int. J. Environ. Res. Public Health 2013, 10 455<br />
3.4. Adverse Events<br />
The most frequently reported adverse events were nausea, shown in 2/14 (14.4%), throat irritation<br />
shown in 2/14 (14.4%), headache shown in 2/14 (14.4%), and dry cough shown in 4/14 (28.6%) (Table 3).<br />
Table 4 shows the distribution of the four most commonly reported adverse events (AEs), separately<br />
for failures, reducers, abstainers. These events were most commonly reported at the beginning of the<br />
study and appeared to wane spontaneously by study visit 5. Withdrawal symptoms were absent (i.e.,<br />
depression, anxiety, insomnia, irritability, hunger, constipation were not reported). Moreover, no<br />
serious adverse events (i.e., events requiring unscheduled visit to the family practitioner or<br />
hospitalization) occurred during the study.<br />
Table 3. Adverse events reported by participants who completed all study visits.<br />
Adverse Event<br />
4-week n/n (%) 8-week n/n (%)<br />
Study Visits<br />
12-week n/n (%) 24-week n/n (%) 52-week n/n (%)<br />
Throat irritation * 1/14 (7.2%) 2/14 (14.4%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Mouth Irritation * 0/14 (0%) 0/14 (0) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Sore Throat 0/14 (0%) 0/14 (0) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Dry cough 4/14 (28.6%) 4/14 (28.6%) 1/14 (7.2%) 0/14 (0%) 0/14 (0%)<br />
Dry mouth 0/14 (0%) 0/14 (0) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Mouth ulcers 0/14 (0%) 0/14 (2.9%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Dizziness § 0/14 (0%) 0/14 (0) 0/14 (10%) 0/14 (0%) 0/14 (0%)<br />
Headache 2/14 (14.4%) 1/14 (7.2%) 1/14 (7.2%) 0/14 (0%) 0/14 (0%)<br />
Nausea 2/14 (14.4%) 0/14 (0%) 1/14 (7.2%) 0/14 (0%) 0/14 (0%)<br />
Depression 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Anxiety 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Insomnia 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Irritability 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Hunger 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
Constipation 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%) 0/14 (0%)<br />
* Throat and mouth irritation were described either as tickling, itching, or burning sensation. § Dizziness, was<br />
also used to mean vertigo and light-headedness.<br />
Table 4. Distribution of the four most commonly reported adverse events (AEs), separately<br />
for failures, reducers, abstainers.<br />
AEs 4-week 8-week 12-week 24-week 52-week<br />
failures (n 2) failures (n 2) failures (n 0) failures (n 0) failures (n 0)<br />
Dry cough reducers (n 1) reducers (n 1) reducers (n 1) reducers (n 0) reducers (n 0)<br />
abstainers (n 1) abstainers (n 1) abstainers (n 0) abstainers (n 0) abstainers (n 0)<br />
failures (n 0) failures (n 0) failures (n 0) failures (n 0) failures (n 0)<br />
Headache reducers (n 1) reducers (n 0) reducers (n 0) reducers (n 0) reducers (n 0)<br />
abstainers (n 1) abstainers (n 1) abstainers (n 1) abstainers (n 0) abstainers (n 0)<br />
failures (n 1) failures (n 0) failures (n 0) failures (n 0) failures (n 0)<br />
Nausea reducers (n 0) reducers (n 0) reducers (n 0) reducers (n 0) reducers (n 0)<br />
abstainers (n 1) abstainers (n 0) abstainers (n 0) abstainers (n 0) abstainers (n 0)<br />
Throat<br />
irritation<br />
failures (n 0)<br />
reducers (n 1)<br />
abstainers (n 0)<br />
failures (n 1)<br />
reducers (n 1)<br />
abstainers (n 0)<br />
failures (n 0)<br />
reducers (n 0)<br />
abstainers (n 0)<br />
failures (n 0)<br />
reducers (n 0)<br />
abstainers (n 0)<br />
failures (n 0)<br />
reducers (n 0)<br />
abstainers (n 0)
Int. J. Environ. Res. Public Health 2013, 10 456<br />
3.5. Positive and Negative Symptoms of Schizophrenia<br />
Positive and negative symptoms of schizophrenia are not increased after smoking reduction/cessation<br />
in patients using e-cigarettes (Table 2). Other studies suggests that positive and negative symptoms of<br />
schizophrenia are not increased after smoking cessation in patients receiving nicotine patches or placebo<br />
patches [28], after smoking reduction following a treatment of bupropion [29], or after smoking reduction<br />
following a treatment of nicotine patches [30].<br />
3.6. Discussion<br />
We have shown for the first time that the use of e-cigarettes substantially decreased cigarette<br />
consumption without causing significant side effects in chronic schizophrenic patients who smoke.<br />
This was achieved without negative impacts on symptoms of schizophrenia as assessed by SAPS and<br />
SANS symptoms scales.<br />
Severity of nicotine dependence, smoking prevalence, and the likelihood of success of quit attempts<br />
are much worse in schizophrenia than in patients with other mental disorders or smokers in the general<br />
population. Therefore, our findings may be of great importance.<br />
Smokers with schizophrenia may use nicotine as a self-medication for the illness. The self<br />
medication hypothesis is supported by study showing that smoking can transiently reverse the deficit [6]<br />
in the processing of auditory stimuli that is found in patients with schizophrenia [31] and by research<br />
suggesting that smoking cigarette has a beneficial effect on visuospatial working memory in smokers<br />
with schizophrenia [32].<br />
Patients with schizophrenia may also smoke to offset the side effects of antipsychotic drugs, as<br />
suggested by research showing that a nicotine patch attenuates the adverse side effects of these drugs [33]<br />
and that cigarette smoking reduces neuroleptic-induced parkinsonism [34].<br />
Another hypothesis is that some antipsychotic drugs may increase smoking, as suggested by<br />
research showing that haloperidol caused a dose-related increase in ad lib smoking in patients with<br />
schizophrenia, in comparison with their baseline level when they were taking no antipsychotic<br />
medications [35].<br />
A further hypothesis is that genetic factors explain the co-occurrence of smoking and<br />
schizophrenia [36], as suggested by research showing that nicotinic receptors are abnormally<br />
expressed [37] and function abnormally in people with schizophrenia [38].<br />
In this pilot study, we have shown for the first time that substantial and objective modifications in<br />
the smoking habits may occur in smokers with schizophrenia using e-cigarettes, with significant<br />
smoking reduction and smoking abstinence and no apparent increase in withdrawal symptoms and in<br />
positive and negative symptoms of schizophrenia. Chronic schizophrenic patients using e-cigarettes<br />
substantially decreased cigarette consumption with an overall quit rate in 2/14 (14.3%) at week-52.<br />
Moreover, at least 50% reduction in cigarette smoking was observed in 7/14 (50%) of participants.<br />
Overall, combined reduction and smoking abstinence was shown in 9/14 (64.3%) of participants. Some<br />
of the smoking/reduction failures could have been related to malfunctions and technical failures of the<br />
product tested in the present study.
Int. J. Environ. Res. Public Health 2013, 10 457<br />
These preliminary findings are of great importance considering that chronic schizophrenic patients<br />
who smoke are generally not interested in quitting. The large magnitude of this effect suggests the<br />
e-cigarette may be a valuable tool of tobacco harm reduction in this special population. These positive<br />
findings may be explained by the great compensatory effect of e-cigarettes at both physical and<br />
behavioral level [9–13,14]; in particular these products are known to provide a coping mechanism for<br />
conditioned smoking cues by replacing some of the rituals associated with smoking gestures (e.g.,<br />
hand-to-mouth action of smoking). In agreement with this, we have recently demonstrated that nicotine<br />
free inhalators can only improve quit rates in those smokers for whom handling and manipulation of<br />
their cigarette played an important role in their ritual of smoking [39].<br />
The most frequent adverse events reported by our patients were throat irritation, nausea, headaches<br />
and dry cough, but all appeared to wane spontaneously with time. Throat irritation and dry cough are<br />
likely to be secondary to exposure to propylene glycol mist generated by the e-cigarette’s atomizer.<br />
Propylene glycol is a low toxicity compound widely used as a food additive and in pharmaceutical<br />
preparations. Exposure to propylene glycol mist may occur from smoke generators in discotheques,<br />
theatres, and aviation emergency training and is known to cause ocular, mouth, throat, upper airway<br />
irritation and cough [40,41].<br />
In contrast with other ENDDs that are known to generate substantial level of eCO [42], in the<br />
present study, the smoking reduction/cessation with “Categoria” e-cigarette use was associated to a<br />
substantial decrease in the level of eCO. This is in agreement with previous studies [17,18].<br />
Therefore, the e-cigarette can be seen as a safe harm-reduction strategies for smokers with<br />
schizophrenia. Harm-reduction strategies are aimed at reducing the adverse health effects of tobacco<br />
use in individuals unable or unwilling to quit. Substantially reducing the number of cig/day is one of<br />
several kinds of harm reduction strategies [43]. Here, we propose an alternative harm reduction<br />
approach for patients with schizophrenia with the e-cigarette being used as a safe alternative source of<br />
nicotine for patients who smoke.<br />
It is uncertain whether substantial smoking reduction in smokers using the e-cigarette will translate<br />
in health benefits, but a number of studies have analyzed the ability of smoking reduction to lower<br />
health risks and have reported some reductions in cardiovascular risk factors and lung cancer<br />
mortality [44–46]. Moreover, reduction in cigarette smoking by e-cigarette may well increase<br />
motivation to quit as indicated by a substantial body of evidence showing that gradually cutting down<br />
smoking can increase subsequent smoking cessation among smokers [47–50].<br />
There are some limitations in our study. Firstly, this was a small uncontrolled study, hence the<br />
results observed may be due to a chance finding and not to a true effect; consequently the results<br />
should be interpreted with caution. However, it would have been quite problematic to have a placebo<br />
arm in such a study. Secondly, this is not an ordinary cessation study and therefore direct comparison<br />
with other smoking cessation products cannot be made. Lastly, assessment of withdrawal symptoms in<br />
our study was not rigorous. Withdrawal was assessed at each visit by simply asking about the<br />
presence/absence of irritability, restlessness, difficulty concentrating, increased appetite/weight gain,<br />
depression or insomnia. It is likely that this way of collecting information is liable to recall bias.<br />
Therefore, the reported lack of withdrawal symptoms in the study participants should be considered<br />
with caution [4].
Int. J. Environ. Res. Public Health 2013, 10 458<br />
4. Conclusions<br />
Even with intensive smoking cessation management programs specifically designed for patients<br />
with schizophrenia, quit rates are low [51]. Although not formally regulated as a pharmaceutical<br />
product, the e-cigarette can help smokers with schizophrenia to reduce their cigarette consumption or<br />
remain abstinent and reduce the burden of smoking-related morbidity and mortality, particularly in<br />
schizophrenic patients who smoke. However, large and carefully conducted RCTs, among healthy<br />
smokers and among persons with more common mental health problems like anxiety ordepression,<br />
will be required before a definite answer about the efficacy and safety of these devices can be<br />
formulated.<br />
Acknowledgments<br />
The authors thank the mental health professionals in Comunità Terapeutica Assistita (CTA) Villa<br />
Chiara- Psichiatrica Riabilitativa e Ricerca, the study participants and their families. We wish to thank<br />
Arbi Group Srl (Milano, Italy) for the free supplies of “Categoria” e-cigarette kits and nicotine<br />
cartridges as well as their support. We would also like to thank LIAF (Lega Italiana AntiFumo) for the<br />
collaboration.<br />
Conflict of Interest<br />
Pasquale Caponnetto, Roberta Auditore, Cristina Russo and Giorgio Carlo Cappello declare no<br />
conflict of interest. Riccardo Polosa has received lecture fees and research funding from Pfizer and<br />
GlaxoSmithKline, manufacturers of stop smoking medications. He has served as a consultant for Pfizer<br />
and Arbi Group Srl (Milano, Italy), the distributor of the Categoria TM e-cigarette.<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
57 Press Release-Observation of electronic ciga-<br />
rette use in France
Respiratory Diseases Departmental Committee, Dordogne (France)<br />
Périgueux, 5 December 2012<br />
Press Release<br />
The use of electronic cigarettes lead to a substantial reduction in tobacco addiction<br />
in 72% of smokers, according to the first study of this device conducted in France<br />
The absence of clinical trials concerning electronic cigarettes makes it impossible to declare them<br />
officially as « health products » enabling smokers to give up or reduce their smoking habits.<br />
However, many smokers have taken up the electronic cigarette with this aim in view. For this<br />
reason the Respiratory Diseases Departmental Committee (Comité Départemental contre les<br />
Maladies Respiratoires) of Dordogne (France) has decided to observe the use of electronic<br />
cigarettes, in collaboration with the Périgueux Health Examinations Centre. This is the first study<br />
of this scope to be published in France.<br />
One hundred smokers declaring that they had no wish to stop smoking in the immediate future<br />
agreed to use a lowerrange electronic cigarette for a period of three months. They were asked to<br />
use this in the place of normal cigarettes, possibly alternating the two. Of the hundred volunteers,<br />
74 respected the study protocol over the threemonth period. Of the 74 participants 53 (72%)<br />
significantly reduced their cigarette smoking, and 8 (11%) stopped smoking completely. The<br />
remaining volunteers declared that they had reduced smoking by less than 50%.<br />
The electronic cigarette was well accepted, by the participants but also by those around them,<br />
family, work colleagues or general public. Two thirds of the electronic smokers noted positive<br />
effects on their health; 15% pointed out discomfort (irritation of the mouth, lips or throat). A<br />
sixmonth appraisal is underway.<br />
Though this first French observation was conducted with limited means, it confirms the potential<br />
of the electronic cigarette in protecting the health of smokers, whether or not they contemplate<br />
giving up smoking.<br />
« One cannot recognize that smoking is the first cause of avoidable deaths, and yet not make any<br />
study of the electronic cigarette, which meets the approval of millions of users worried about their<br />
health » declared Dr Jacques Granger, President of the Respiratory Diseases Departmental<br />
Committee of Dordogne. This observation carried out on one hundred electronic cigarette<br />
smokers calls for other more detailed studies. There is a clear improvement over three months in<br />
the state of health of those who took part, without any serious sideeffects, and there is no lack of<br />
volunteers.<br />
Contact : Luc DUSSART 1r9csoeur1@gmail.com +33 663 650 144<br />
On line version : Press Release Observation of electronic cigarette use in France, 5 December 2012
Nachschlagewerk zum Thema E-Zigaretten<br />
58 Electronic Nicotine Delivery Systems
Introduction<br />
Electronic Nicotine Delivery Systems<br />
International Tobacco Control Four-Country Survey<br />
Sarah E. Adkison, MA, Richard J. O’Connor, PhD, Maansi Bansal-Travers, PhD,<br />
Andrew Hyland, PhD, Ron Borland, PhD, Hua-Hie Yong, PhD,<br />
K. Michael Cummings, MPH, PhD, Ann McNeill, PhD, James F. Thrasher, PhD,<br />
David Hammond, PhD, Geoffrey T. Fong, PhD<br />
Background: Electronic nicotine delivery systems (ENDS) initially emerged in 2003 and have since<br />
become widely available globally, particularly over the Internet.<br />
Purpose: Data on ENDS usage patterns are limited. The current paper examines patterns of ENDS<br />
awareness, use, and product-associated beliefs among current and former smokers in four countries.<br />
Methods: Data come from Wave 8 of the International Tobacco Control Four-Country Survey,<br />
collected July 2010 to June 2011 and analyzed through June 2012. Respondents included 5939 current<br />
and former smokers in Canada (n1581); the U.S. (n1520); the United Kingdom (UK; n1325);<br />
and Australia (n1513).<br />
Results: Overall, 46.6% were aware of ENDS (U.S.: 73%, UK: 54%, Canada: 40%, Australia:<br />
20%); 7.6% had tried ENDS (16% of those aware of ENDS); and 2.9% were current users (39% of<br />
triers). Awareness of ENDS was higher among younger, non-minority smokers with higher<br />
incomes who were heavier smokers. Prevalence of trying ENDS was higher among younger,<br />
nondaily smokers with a high income and among those who perceived ENDS as less harmful<br />
than traditional cigarettes. Current use was higher among both nondaily and heavy (20<br />
cigarettes per day) smokers. In all, 79.8% reported using ENDS because they were considered less<br />
harmful than traditional cigarettes; 75.4% stated that they used ENDS to help them reduce their<br />
smoking; and 85.1% reported using ENDS to help them quit smoking.<br />
Conclusions: Awareness of ENDS is high, especially in countries where they are legal (i.e., the U.S.<br />
and UK). Because trial was associated with nondaily smoking and a desire to quit smoking, ENDS<br />
may have the potential to serve as a cessation aid.<br />
(Am J Prev Med 2013;44(3):207–215) © 2013 American Journal of Preventive Medicine<br />
Electronic nicotine delivery systems (ENDS; also<br />
called e-cigarettes) initially emerged in China in<br />
2003 and have since become widely available globally,<br />
particularly over the Internet. ENDS heat and vapor-<br />
From the Department of Health Behavior (Adkison, O’Connor, Bansal-<br />
Travers, Hyland), Roswell Park Cancer Institute, Buffalo, New York; The<br />
Cancer Council Victoria (Borland, Yong), Carlton, Victoria, Australia;<br />
Department of Psychiatry and Behavioral Sciences (Cummings), Medical<br />
University of South Carolina, Charleston; Department of Health Promotion,<br />
Education, and Behavior (Thrasher), University of South Carolina,<br />
Columbia, South Carolina; Division of Epidemiology and Public Health<br />
(McNeill), University of Nottingham, United Kingdom; and School of<br />
Public Health & Health Systems (Hammond), and Department of Psychology<br />
(Fong), University of Waterloo, Waterloo, Ontario, Canada<br />
Address correspondence to: Richard J. O’Connor, PhD, Associate Professor<br />
of Oncology, Department of Health Behavior, Roswell Park Cancer<br />
Institute, Buffalo NY 14263. E-mail: Richard.oconnor@roswellpark.org.<br />
0749-3797/$36.00<br />
http://dx.doi.org/10.1016/j.amepre.2012.10.018<br />
ize a solution containing nicotine, and many are designed<br />
to resemble traditional tobacco cigarettes. Some advocates<br />
of tobacco harm reduction have pointed to these<br />
products as viable substitutes for cigarettes because they<br />
produce fewer toxins in the vapor delivered to the user. 1–5<br />
However, concerns exist regarding unknown long-term<br />
safety; inadequate data on contents and emissions, especially<br />
with long-term use; and unsupported product<br />
claims as a smoking-cessation aid. 6–9<br />
There also may be unintended consequences associated<br />
with ENDS use, including the potential to induce<br />
nicotine addiction in nonsmokers or maintain addiction<br />
in current smokers who might otherwise quit. Additionally,<br />
concerns have been raised that ENDS may undermine<br />
comprehensive indoor smoking restrictions and<br />
smokefree air policies. 10 Because of these concerns,<br />
ENDS have been banned in Canada (www.hc-sc.gc.ca/<br />
ahc-asc/media/advisories-avis/_2009/2009_53-eng.php)<br />
© 2013 American Journal of Preventive Medicine • Published by Elsevier Inc. Am J Prev Med 2013;44(3):207–215 207
208 Adkison et al / Am J Prev Med 2013;44(3):207–215<br />
and Australia (www.tga.gov.au/consumers/ecigarettes.<br />
htm); however, they are legal in the U.S. and the United<br />
Kingdom (UK). Despite bans on retail sale, access is diffıcult<br />
to control because the products are marketed heavily over<br />
the Internet.<br />
Because ENDS are relatively new, data on usage patterns<br />
are sparse. 11 Surveys of self-selected ENDS users suggest<br />
that many are former or current cigarette smokers who use<br />
the products to reduce or quit smoking. 2,12,13 A survey of a<br />
broader U.S. population showed that awareness of ENDS<br />
increased from 16.4% in 2009 to 32.2% in 2010, concurrent<br />
with a rise in ever-use (0.6% in 2009 to 2.7% in 2010). 14<br />
Ever-use was concentrated primarily among tobacco users.<br />
A nationally representative sample of U.S. adults found that<br />
40.2% were aware of ENDS, and awareness and use was<br />
highest among current smokers (ever use: 11.4% current<br />
smokers, 2.0% former smokers, 0.8% never smokers). 15 An<br />
online survey of approximately 2500 smokers in England in<br />
2010 found that around 60% were aware of ENDS, 9% had<br />
tried them, and 3% were current users. 16 The current authors<br />
are not aware of any studies to date that have examined<br />
cross-national patterns of ENDS use, and no studies have<br />
examined use in markets where ENDS are nominally<br />
banned. The current paper examines patterns of ENDS<br />
awareness, use, and product-associated beliefs among current<br />
and former cigarette smokers in the U.S., Canada, Australia,<br />
and the UK.<br />
Methods<br />
Data come from Wave 8 of the International Tobacco Control<br />
(ITC) Four-Country Survey conducted July 2010 to June 2011 in<br />
the U.S., Canada, Australia, and the UK via telephone interviews<br />
and web surveys. Additionally, where available, data from Wave 7<br />
(conducted October 2008 to July 2009) were analyzed to explore<br />
changes in smoking behavior between ENDS users and non-users.<br />
Details about the study design, sampling frames, and overall aims<br />
of the project are described elsewhere. 17,18<br />
At initial enrollment, respondents included adult smokers aged<br />
18 years who smoked at least 100 cigarettes in their lifetime and at<br />
least 1 cigarette in the past 30 days at the time of recruitment.<br />
Probability sampling methods were used to recruit the sample<br />
using random-digit dialing. If multiple adult smokers were present<br />
in the home, the next-birthday method was used to select the<br />
respondent. Those who quit smoking remained in the sample for<br />
follow-up interviews. Respondents who were lost at each wave were<br />
replenished using the same procedures as the original recruitment<br />
except in the UK. Data were collected for 5939 respondents across<br />
the four countries at Wave 8: U.S. (n1520); Canada (n1581);<br />
Australia (n1513); UK (n1325).<br />
Measures<br />
In addition to the main tobacco use questions asked in previous waves,<br />
the Wave-8 survey included additional questions regarding awareness<br />
and use of ENDS. These include Have you ever heard of electronic<br />
cigarettes or e-cigarettes? Have you ever tried an electronic cigarette?<br />
and How often, if at all, do you currently use an electronic cigarette?<br />
Current ENDS users were asked four questions regarding their reasons<br />
for use (yes/no). These include the following: (1) electronic cigarettes<br />
may not be as bad for your health; (2) easier to cut down on the<br />
number of cigarettes you smoke; (3) can smoke in places where smoking<br />
regular cigarettes is banned; and (4) might help you quit. All<br />
respondents aware of ENDS were asked whether or not they thought<br />
electronic cigarettes were more harmful than, less harmful than, or<br />
equally harmful as regular cigarettes to one’s health.<br />
Data Analysis<br />
Data were analyzed using SPSS 16.0. Differences in demographic and<br />
smoking-related variables of respondents who were aware of, tried,<br />
and used ENDS compared to those who were not were evaluated with<br />
chi-square tests. Logistic regression was used to evaluate the independent<br />
influence of the predictors of awareness, trial, and use. The entire<br />
sample was used to estimate prevalence; however, the analytic samples<br />
for the logistic regression models varied by dependent variable. For<br />
models predicting awareness, the entire sample was analyzed; for<br />
models predicting ever-use, only participants who were aware of<br />
ENDS were analyzed; for models predicting current use, only participants<br />
who had ever used ENDS were analyzed. Each analysis was<br />
adjusted with sample weights that accounted for sampling probability<br />
and the known distribution of gender, age, and race within the smoker<br />
population for each country.<br />
Results<br />
Prevalence of Awareness, Trial, and Usage<br />
Across countries, nearly half (46.6%, n2757) of respondents<br />
reported having heard of ENDS. Analyses revealed<br />
differences in ENDS awareness by country, 2 (3,<br />
n5921)932.5 (p0.001). Greatest awareness was reported<br />
in countries where the use of ENDS is mostly<br />
permitted; nearly three quarters (73.4%) of respondents<br />
in the U.S. and more than half (54.4%) of respondents in<br />
the UK indicated awareness of these devices. Where<br />
ENDS were banned, awareness was lower but still substantial,<br />
with 39.5% and 20.0% reporting awareness in<br />
Canada and Australia, respectively (Table 1).<br />
Overall, 7.6% (n450) of respondents had tried ENDS<br />
(16.3% of those aware). Among those aware, trial was<br />
more prevalent in some countries, 2 (3, n2755)38.2<br />
(p0.001): 20.4% in the U.S. and 17.7% in the UK reported<br />
trying ENDS, whereas 10.1% in Canada and 10.9%<br />
in Australia reported doing so. Approximately 3% of<br />
respondents (38.7% of triers) reported current use at the<br />
time of the survey. Current use was not different across<br />
the four countries, 2 (3, n450)5.96 (p0.114).<br />
Sociodemographic and Smoking-Related<br />
Correlates of Awareness<br />
Younger, higher-income, well-educated respondents<br />
were more likely to report ENDS awareness overall and in<br />
each country. Daily smokers, those who smoked menthol<br />
cigarettes, men, and respondents who took the survey<br />
www.ajpmonline.org
Table 1. Prevalence of ENDS awareness, trial, and use among current and former tobacco users, % yes (SE)<br />
Country<br />
Aware of ENDS<br />
(overall)<br />
Tried ENDS<br />
(overall )<br />
over the Internet were more likely to be aware of ENDS<br />
overall. In the U.S., greater awareness also was reported<br />
among white respondents, English-speaking respondents,<br />
and among those who had a complete ban on<br />
smoking within the home. In the UK, men were more<br />
likely to be aware of ENDS (Table 2).<br />
Logistic regression was used to evaluate independent<br />
correlates of ENDS awareness across the four countries<br />
(Table 3). Across-country analysis was chosen because<br />
model fıt was superior to that for within-country analysis<br />
(across: Nagelkerke R 2 0.25, receiver operating characteristic<br />
[ROC]0.76, Hosmer-Lemeshow [H-L] statistic<br />
for across-country analysis insignifıcant, p0.25); –2 loglikelihood<br />
showed improved fıt with the inclusion of the<br />
country variable (without: 7146.50, with: 6243.78, withincountry<br />
analysis: Nagelkerke R 2 range0.07–0.11, ROC<br />
range0.64–0.68, H-L: signifıcant in Canada, U.S., UK).<br />
To assess how smoking behavior influenced awareness, a<br />
fıve-level smoking status measure was constructed, comprising<br />
two daily use categories (0–20 cigarettes per day<br />
[cpd] and 21 cpd); a nondaily use category; and two<br />
quitter categories (recent [12 months] and long-term<br />
[12 months]).<br />
Respondents in the U.S. (OR4.86, CI4.09, 5.77)<br />
and the UK (OR2.090, CI1.77, 2.47) had greater odds<br />
of having heard of ENDS than those in Canada, whereas<br />
Australian respondents had lower odds (OR0.37,<br />
CI0.31, 0.44). Heavy smokers (20 cpd) had the greatest<br />
(OR1.24, CI1.04, 1.48) and long-term quitters had<br />
the lowest odds (OR0.83, CI0.69, 1.00) of awareness.<br />
Consistent with the chi-square analysis, young, welleducated,<br />
higher-income, male smokers and those who<br />
responded via the Internet had greater odds of ENDS<br />
awareness.<br />
Tried ENDS<br />
(among aware)<br />
Current ENDS<br />
user (overall)<br />
Current ENDS user<br />
(among tried)<br />
All countries 46.56 (.6) 7.6 (0.3) 16.3 (0.7) 2.9 (0.2) 38.7 (2.3)<br />
n 5921 5939 2755 5939 450<br />
Canada 39.53 (1.2) 4 (0.5) 10 (1.2) 1 (0.3) 33 (6.0)<br />
n 1571 1581 621 1581 63<br />
U.S. 73.43 (1.1) 14.9 (0.9) 20.4 (1.2) 6 (0.6) 37 (3.2)<br />
n 1517 1520 1113 1520 227<br />
United Kingdom 54.42 (14.0) 9.6 (0.8) 17.7 (1.4) 4 (0.6) 46 (4.4)<br />
n 1323 1325 719 1325 127<br />
Australia 20.00 (1.0) 2 (0.4) 11 (1.8) 1 (0.2) 27 (7.9)<br />
n 1510 1513 302 1513 33<br />
ENDS, electronic nicotine delivery systems<br />
March 2013<br />
Adkison et al / Am J Prev Med 2013;44(3):207–215 209<br />
Sociodemographic and Smoking-Related<br />
Correlates of Trial<br />
Chi-square analyses showed that, among those aware,<br />
younger, female respondents were more likely to try<br />
ENDS. Current rather than former smokers and current<br />
nondaily smokers were more likely to try ENDS. Those<br />
who smoked menthol cigarettes were more likely to try<br />
ENDS than respondents who smoked nonmenthol cigarettes.<br />
Survey mode was related to having tried these<br />
devices; however, unlike the association for awareness,<br />
telephone respondents were most likely to have tried<br />
ENDS. Within-country chi-square tests showed this association<br />
was only signifıcant in the U.S.<br />
In the U.S., greater ENDS trial was reported among<br />
younger, white, nondaily, higher-income smokers. In<br />
the UK, trial was more common among younger and<br />
higher-income smokers, and among women and minority<br />
populations. In Australia and Canada, where<br />
ENDS were banned, few demographic characteristics<br />
were associated with having tried ENDS, although<br />
nondaily smokers in Australia were more likely to have<br />
tried ENDS (32%).<br />
Among those aware, independent correlates of those<br />
who tried ENDS were assessed (Table 3). Across-country<br />
analysis was employed consistent with the model for<br />
awareness. Model-fıt statistics were similar for the acrossand<br />
within-country analysis (across: Nagelkerke R 2 <br />
0.179, ROC0.786, H-L insignifıcant, p0.152); model<br />
fıt improved with the inclusion of the country variable<br />
(–2 log-likelihood, without: 1929.37, with: 1893.67). For<br />
within-country analysis, Nagelkerke R 2 range0.177–<br />
0.265, ROC range0.729–0.837, and H-L signifıcant in<br />
Australia.
210 Adkison et al / Am J Prev Med 2013;44(3):207–215<br />
Table 2. Correlates of ENDS awareness overall and by country and sample demographics, %<br />
Variable<br />
Age (years)<br />
All countries Canada U.S. United Kingdom Australia<br />
Aware Sample Aware Sample Aware Sample Aware Sample Aware Sample<br />
18–24 67.8 5.1 36 2 95 6 63 4 55 9<br />
25–39 52.5 33.2 48.5 31.4 79.0 32.1 61.4 33.8 24 39<br />
40–54 43.8 33.9 37.1 37.2 73.4 34.5 53.7 31.1 16 29<br />
55 41.7 27.8 35.7 29.5 64.7 27.2 48.0 29.6 16 22<br />
2 (n5920)86.40**** (n1571)18.45**** (n1517)42.03**** (n1321)16.65**** (n1510)53.36****<br />
Gender<br />
Female 44.9 44.8 38.5 44.8 72.2 44.2 51.1 46.4 18.8 43.0<br />
Male 48.0 55.2 40.5 55.2 74.4 55.8 57.7 53.6 21.0 57.0<br />
2 (n5920)5.72*** (n1570)0.68 (n1517)0.89 (n1322)5.72*** (n1510)1.07<br />
Race<br />
White 46.5 88.9 39.4 90.8 75.8 83.2 55.0 95.7 19.8 89.8<br />
Nonwhite 47.5 11.1 42 9 64.6 16.8 44 4 21 10<br />
2 (n5877)0.22 (n1571)0.34 (n1501)14.98**** (n1323)3.50* (n1486)0.07<br />
Income<br />
Low 43.1 25.2 29 16 66.3 32.7 47.3 26.7 13 14<br />
Moderate 47.6 33.6 42.3 40.3 77.3 33.6 53.0 29.6 20 30<br />
High 47.8 41.1 42.1 43.8 77.9 33.8 62.6 43.7 23.5 55.9<br />
2 (n5443)9.38*** (n1439)16.47**** (n1378)20.75**** (n1200)20.24**** (n1426)13.78****<br />
Education a<br />
Low 41.9 42.5 35.5 36.9 68.8 37.9 54.1 54.4 16.0 43.4<br />
Moderate 50.3 35.0 44.1 43.2 78.7 39.4 50.1 23.6 21 29<br />
High 51.5 22.4 38.8 19.9 73.5 22.7 60.6 22.0 30 27<br />
2 (n5904)47.30**** (n1566)9.73*** (n1515)14.51**** (n1315)6.52** (n1509)25.31****<br />
Smoking frequency<br />
Smoker 47.7 77.5 39.5 76.7 73.6 80.3 55.9 75.4 20.5 74.5<br />
Quitter 43.2 22.5 39.7 23.3 72.5 19.7 50.1 24.6 19 25<br />
2 (n5920)8.82*** (n1570)0.01 (n1516)0.16 (n1322)3.50* (n1509)0.62<br />
Smoking frequency<br />
Daily 47.8 71.7 39.4 70.4 73.7 73.9 56.3 72.3 20.0 65.2<br />
Nondaily 45.9 5.8 41 6 73 6 9 3 25 9<br />
Quitter 43.2 22.5 39.7 23.3 72.5 19.7 50.1 24.6 19 26<br />
2 (n5921)9.26*** (n1571)0.16 (n1515)0.18 (n1322)4.44 (n1510)1.93<br />
Plan to quit<br />
Yes/Quit 46.7 81.1 40.3 83.4 74.3 82.3 54.8 74.4 20.8 88.4<br />
No 46.0 18.9 35.9 16.6 70.3 17.7 53.8 25.6 16.1 11.6<br />
2 (n5854)0.15 (n1552)1.87 (n1486)1.86 (n1319)0.09 (n1498)2.48<br />
(continued on next page)<br />
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Table 2. (continued)<br />
Variable<br />
Smoke menthol<br />
cigarettes<br />
All countries Canada U.S. United Kingdom Australia<br />
Aware Sample Aware Sample Aware Sample Aware Sample Aware Sample<br />
Yes 57.1 16.0 45 6 69.8 29.2 61 6 20 9<br />
No 46.3 84.0 38.9 93.8 76.1 70.8 55.6 94.4 20.8 90.6<br />
2 (n4436)24.17**** (n1193)0.84 (n1195)5.26** (n965)0.60 (n1083)0.08<br />
Home smoking ban<br />
Yes 45.0 47.1 40.3 47.7 77.3 50.9 52.3 36.5 19.0 57.6<br />
No 48.1 52.9 39.0 52.3 69.7 49.1 55.8 63.5 21.5 42.4<br />
2 (n5912)5.50** (n1568)0.26 (n1513)11.16**** (n1322)1.55 (n1509)1.44<br />
Survey mode<br />
Telephone 44.1 60.5 32.7 49.7 72.7 69.9 50.5 59.4 16.5 50.3<br />
Web 51.0 39.5 50.0 50.3 75.1 30.1 61.2 40.6 25.5 49.7<br />
2 (n5920)25.88**** (n1572)47.35**** (n1517)0.91 (n1322)14.03**** (n1509)17.95****<br />
Note: Boldface indicates significance.<br />
aEducation level: lowhigh school or less; moderatesome technical school or some university; highUniversity degree or more.<br />
*p0.10; **p0.05; ***p0.01; ****p0.001<br />
ENDS, electronic nicotine delivery systems<br />
Respondents in the U.S. and UK had approximately<br />
two times greater odds of trying ENDS than Canadians.<br />
Consistent with awareness, younger (aged 18–24 years)<br />
and high-income respondents had greater odds of trying<br />
ENDS. Of particular interest, ENDS trial was associated<br />
with respondent smoking status and perceptions of harm.<br />
Nondaily smokers had nearly two times greater odds of<br />
reporting ever-use than respondents who smoked 20<br />
cpd. Those who reported that ENDS were less harmful<br />
than traditional cigarettes had nearly four times greater<br />
odds of trying ENDS.<br />
Sociodemographic and Smoking-Related<br />
Correlates of Current Use<br />
Correlates of continued ENDS use among those who have<br />
tried ENDS included education and frequency of smoking.<br />
Half (51%) of those in the highest education bracket<br />
reported continued use, 2 (2, n451)10.72 (p0.005).<br />
Additionally, current nondaily smokers (58%) were more<br />
likely than daily smokers (35.9%) to continue use,<br />
2 (1, n402)8.998 (p0.003).<br />
Logistic regression of independent correlates of use<br />
among triers was employed across country (across:<br />
Nagelkerke R 2 0.175, ROC0.726, H-L p0.03; model<br />
fıt improved with inclusion of the country variable: –2<br />
log-likelihood, without: 484.71, with: 475.39). This analysis<br />
showed that among triers, odds of continuing ENDS<br />
use did not vary by country (Table 3). Additionally, welleducated,<br />
nondaily smokers had greater odds of contin-<br />
March 2013<br />
Adkison et al / Am J Prev Med 2013;44(3):207–215 211<br />
ued use and heavier (20 cpd) and nondaily smokers had<br />
greater odds of continued use than quitters. Additional<br />
logistic regression analyses among current smokers<br />
showed that heaviness of smoking was not associated<br />
with trial or continued use of ENDS.<br />
Perceptions of Risk<br />
All respondents who were aware of ENDS were asked<br />
about their perceptions of risk associated with use. The<br />
vast majority of respondents who were aware of ENDS<br />
reported that ENDS were less harmful than traditional<br />
cigarettes (all: 70.3%; Canada: 63.9%; U.S.: 65.9%; UK:<br />
82.2%; Australia: 71.0%). Chi-square analyses revealed<br />
that these cross-country differences were signifıcant,<br />
2 (2, n2746)71.464 (p0.001). Perceptions of<br />
harm were higher in the U.S. than the UK,<br />
2 (2, n1825)58.155 (p0.001), where ENDS are legal,<br />
and perceptions of harm in Canada were higher than<br />
they were in Australia, 2 (2, n921)4.522 (p0.03),<br />
where ENDS are banned.<br />
Reduction in Cigarettes Per Day and in<br />
Quitting Over Time<br />
Current ENDS users were asked questions regarding<br />
their reasons for use (Figure 1). The majority of respondents<br />
indicated that they used ENDS to reduce the harm<br />
of, or to help themselves quit using, traditional cigarettes.
212 Adkison et al / Am J Prev Med 2013;44(3):207–215<br />
Table 3. Logistic regression of awareness, trial, and current use of ENDS, OR (95% CI)<br />
Variable Heard of ENDS Tried ENDS Current ENDS user<br />
Country<br />
Canada ref ref ref<br />
U.S. 4.86**** (4.09, 5.77) 2.24**** (1.59, 3.16) 1.08 (0.52, 2.12)<br />
United Kingdom 2.09**** (1.77, 2.47) 1.86**** (1.30, 2.68) 2.07* (0.96, 4.45)<br />
Australia<br />
Smoking frequency<br />
0.37**** (0.31, 0.44) 0.84 (0.51, 1.39) 0.58 (0.19, 1.78)<br />
Daily, 1–20 cpd ref ref ref<br />
Daily, 20 cpd 1.24** (1.04, 1.48) 0.96 (0.69, 1.35) 2.36** (1.22, 4.57)<br />
Nondaily smoker 0.97 (0.75, 1.26) 1.85*** (1.23, 2.78) 3.02*** (1.4, 6.52)<br />
Recent quitter 0.88 (0.71, 1.10) 1.07 (0.71, 1.62) 1.91 (0.83, 4.40)<br />
Long-term quitter<br />
Ethnicity<br />
0.83** (0.69, 1.00) 0.13**** (0.06, 0.27) 0.10 (0.01, 1.62)<br />
Nonwhite/non–English ref ref ref<br />
White/English<br />
Gender<br />
1.30*** (1.07, 1.59) 1.35 (0.91, 2.02) 1.75 (0.76, 4.07)<br />
Male ref ref ref<br />
Female<br />
Age (years)<br />
0.82**** (0.73, 0.93) 1.22* (0.97, 1.54) 1.26 (0.79, 2.00)<br />
18–24 ref ref ref<br />
25–39 0.52**** (0.36, 0.76) 0.53*** (0.33, 0.84) 0.73 (0.32, 1.68)<br />
40–54 0.36**** (0.25, 0.53) 0.34**** (0.21, 0.55) 1.07 (0.47, 2.47)<br />
55–Max<br />
Education<br />
0.35**** (0.24, 0.51) 0.35**** (0.21, 0.57) 1.19 (0.50, 2.83)<br />
Low ref ref ref<br />
Moderate 1.22*** (1.06, 1.40) 1.00 (0.77, 1.31) 0.72 (0.43, 1.22)<br />
High<br />
Income<br />
1.09 (0.92, 1.29) 0.90 (0.66, 1.24) 2.14** (1.13, 4.05)<br />
Low ref ref ref<br />
Moderate 1.47**** (1.25, 1.72) 1.17 (0.85, 1.60) 0.96 (0.51, 1.80)<br />
High<br />
Perceptions of harm<br />
1.57**** (1.34, 1.85) 1.57*** (1.15, 2.14) 1.28 (0.69, 2.35)<br />
Less harmful than cigarettes — 3.74**** (2.64, 5.30) 1.78 (0.81, 3.91)<br />
equally or more harmful a<br />
Plan to quit smoking<br />
— ref ref<br />
Yes/already quit ref ref ref<br />
No 0.95 (0.80, 1.11) 1.10 (0.82, 1.47) 1.10 (0.62, 1.95)<br />
(continued on next page)<br />
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Table 3. (continued)<br />
Variable Heard of ENDS Tried ENDS Current ENDS user<br />
Cohort<br />
Wave of recruitment<br />
Survey mode<br />
1.06**** (1.03, 1.09) 1.07** (1.01, 1.13) 1.14** (1.01, 1.28)<br />
Telephone ref ref ref<br />
Web 1.60**** (1.40, 1.83) 0.87 (0.68, 1.12) 0.95 (0.57, 1.58)<br />
n 5307 2321 335<br />
–2 log-likelihood 6243.77 1893.67 475.39<br />
Note: Boldface indicates significance.<br />
a Response options include more harmful, equally harmful, and don’t know.<br />
*p0.10, **p0.05, ***p0.01, ****p0.001<br />
cpd, cigarettes per day; ENDS, electronic nicotine delivery systems<br />
Three quarters of users reported use to help them reduce<br />
the number of cigarettes they smoke.<br />
To evaluate claims of reduction in cigarette use, change<br />
in the number of cigarettes per day was assessed between<br />
Wave 7 and Wave 8. A repeated-measures ANOVA,<br />
among smokers at Wave 7 with wave (Waves 7 and 8) as<br />
the within-subjects factor and user status (ENDS user<br />
versus non-user) as the between-subjects factor, showed<br />
an interaction between user status and Wave. ENDS users<br />
were more likely to have reduced their cigarettes per day<br />
between waves than non-users, F (1, 4092)4.65<br />
(p0.05). For users in Wave 7, M20.10, SD12.36; for<br />
those in Wave 8, M16.32, SD12.35. For non-users in<br />
Wave 7, M16.86, SD9.95; for those in Wave 8,<br />
M15.01, SD10.83. Notably, 85% (n146) of current<br />
ENDS users stated that they used ENDS as a tool to help<br />
them quit smoking, although only 11% of current ENDS<br />
users report having quit since Wave 7. Quitting did not<br />
differ between users and non-users, 2 (2, n4136)<br />
0.422 (p0.516).<br />
Use in smokefree zones<br />
Help me reduce<br />
Less-harmful<br />
Help me quit<br />
0 20 40 60 80 100<br />
Percentage<br />
Figure 1. Percentage of current ENDS users who stated<br />
that they used ENDS for various reasons<br />
ENDS, electronic nicotine delivery systems<br />
March 2013<br />
Adkison et al / Am J Prev Med 2013;44(3):207–215 213<br />
Discussion<br />
Nationally representative samples of current and former<br />
smokers surveyed in the four largest English-speaking<br />
countries showed substantial awareness of ENDS, ranging<br />
from 73% in the U.S. to 20% in Australia. Among<br />
those aware, 16% had tried ENDS (7.6% of the total<br />
sample), and among those who had tried ENDS, 39%<br />
(2.9% of the sample) were current users. Across countries,<br />
awareness of these relatively new products was<br />
higher among younger, non-minority populations with<br />
higher incomes. Trial and use of ENDS was associated<br />
with smoking status and frequency of smoking, with nondaily<br />
smokers being the most likely to try ENDS, although<br />
there were few nondaily smokers in the sample. Current<br />
use was associated with a greater reduction in cigarettes<br />
per day over time, compared to non-ENDS users (among<br />
cohort participants, where data were available); however,<br />
users were not more likely to quit smoking than<br />
non-users.<br />
The relatively higher prevalence of ENDS use among<br />
nondaily smokers may have multiple explanations. First,<br />
nondaily smokers may supplement their nicotine intake<br />
from other sources, as smoking is restricted in public<br />
places and cigarettes are increasingly expensive. As more<br />
data become available, it will be important to evaluate<br />
whether ENDS use is related to supplementing due to<br />
smoking restrictions at home, in the workplace, or other<br />
public spaces with smokefree policies. The available data<br />
for this sample did not show a difference in trial of ENDS<br />
between respondents who did versus those who did not<br />
have complete smoking bans in the home, although continued<br />
use was more likely among respondents in the U.S.<br />
who did not have home smoking bans. Second, the use of<br />
ENDS may have driven smokers to reduce their overall<br />
cigarette smoking to a nondaily pattern.
214 Adkison et al / Am J Prev Med 2013;44(3):207–215<br />
Consistent with previous research, 12,13,19 the majority<br />
of survey participants indicated that they used ENDS to<br />
reduce the harm of traditional cigarettes or to help them<br />
quit traditional cigarettes. This association between trial<br />
and intention to quit smoking reflects on the potential for<br />
ENDS as cessation tools, as reported by many selfselected<br />
ENDS users. 2,4,12,13 However, in the absence of a<br />
clinical RCT to evaluate the effıcacy of ENDS as a stopsmoking<br />
aid, it is hard to judge claims about the effectiveness<br />
of these products as treatments for nicotine<br />
addiction.<br />
To date, one study has assessed ENDS as a harm reduction<br />
and cessation aid with promising results. 19 However,<br />
nearly three quarters (70.4%) of this sample reported that<br />
they used ENDS as a way to obtain nicotine in smokefree<br />
spaces, indicating that ENDS are being used also to satisfy<br />
nicotine addiction during periods of temporary abstinence.<br />
With the addition of future International Tobacco<br />
Control survey waves, it will be possible to track whether<br />
those self-selecting to use ENDS compared to those not<br />
using ENDS are more or less successful with their efforts<br />
to abstain from smoking.<br />
Levels of awareness, trial, and use were surprisingly<br />
high in two countries where the products are nominally<br />
illegal (Canada, Australia), which may demonstrate the<br />
importance of the Internet in promoting the product, 20<br />
the ease with which products can be imported for personal<br />
use, and illegal sales. Indeed, those who responded<br />
via a computer-based survey, which may indicate greater<br />
use of and familiarity with the Internet, were more likely<br />
to report awareness of these devices. These fındings demonstrate<br />
how easily product restrictions can be evaded in<br />
the Internet age, and this should be of importance to<br />
regulators. Future studies should investigate how ENDS<br />
users obtain their device, determine the market share of<br />
various ENDS products in use, and how product delivery<br />
and marketing influences usage patterns.<br />
Limitations<br />
A limitation of the current study is inclusion of only<br />
current and former cigarette smokers. Understanding the<br />
awareness, trial, and use of ENDS among nonsmokers, in<br />
particular adolescents, is of great importance to understanding<br />
their potential impact on public health. Some<br />
research shows that adolescents not otherwise susceptible<br />
to cigarette smoking were less likely to be aware of or use<br />
ENDS (J Delmerico, Roswell Park Cancer Institute, unpublished<br />
observations, 2012). Research among adults<br />
also shows that ever-use of ENDS among never-smokers<br />
is low. 14,15 Additionally, the limited set of questions<br />
touched only on awareness, trial, use, and selected reasons<br />
for use, and did not address issues related to ENDS<br />
marketing, product characteristics, or pricing.<br />
Conclusion<br />
This study represents a snapshot in time of the use of ENDS<br />
from mid-2010 to mid-2011. As the market evolves, awareness,<br />
trial, and use of ENDS is likely to increase. The association<br />
of trial and current use with beliefs about the relative<br />
safety of ENDS highlights the importance of marketing in<br />
shaping public perceptions around the product. Should regulatory<br />
authorities approve direct claims about reduced<br />
harm, one might expect greater adoption of these products,<br />
at least among current cigarette smokers. If credible evidence<br />
can be provided that ENDS reduces the number of<br />
cigarette smokers and does not attract use among nonsmokers,<br />
then the net public health effect is likely to be positive.<br />
The International Tobacco Control Four-Country Project was<br />
supported by the U.S. National Cancer Institute (RO1 CA100362<br />
and P01 CA138389); Canadian Institutes of Health Research<br />
(79551 and 115016); National Health and Medical Research Council<br />
of Australia (450110, APP1005922); Cancer Research UK<br />
(C312/A11943); Ontario Institute for Cancer Research (Senior<br />
Investigator Award to GTF); and Canadian Cancer Society Research<br />
Institute (Prevention Scientist Award to GTF). RJO has<br />
consulted for the U.S. Food and Drug Administration and the<br />
WHO concerning tobacco product regulation. KMC has consulted<br />
with various manufacturers of stop-smoking medications in<br />
the past, and currently serves as a paid expert witness in litigation<br />
against cigarette manufacturers. RB has consulted to the Australian<br />
Department of Health on tobacco control issues.<br />
No other fınancial disclosures were reported by the authors<br />
of this paper.<br />
References<br />
1. Cahn Z, Siegel M. Electronic cigarettes as a harm reduction strategy for<br />
tobacco control: a step forward or a repeat of past mistakes? J Public<br />
Health Policy. 2011;32(1):16–31.<br />
2. Siegel MB, Tanwar KL, Wood KS. Electronic cigarettes as a smokingcessation<br />
tool: results from an online survey. Am J Prev Med<br />
2011;40(4):472–5.<br />
3. Borland R. Electronic cigarettes as a method of tobacco control. Br<br />
Med J 2011;343:1238.<br />
4. Foulds J, Berg A, Veldheer S. Electronic cigarettes (e-cigs): views of<br />
afıcionados and clinical/public health perspectives. Int J Clin Pract<br />
2011;65(10):1037–42.<br />
5. Wagener TL, Siegel M, Borrelli B. Electronic cigarettes: achieving a<br />
balanced perspective. Addiction. 2012;107(4). E-pub Apr 4, 2012.<br />
6. Williams M, Talbot P. Variability among electronic cigarettes in the<br />
pressure drop, airflow rate, and aerosol production. Nicotine Tob Res<br />
2011;13(12):1276–83.<br />
7. Trtchounian A, Talbot P. Electronic nicotine delivery systems: is there<br />
a need for regulation? Tob Control. 2010;20:47–52.<br />
8. Cobb NK, Abrams DB. E-cigarette or drug-delivery device? Regulating<br />
novel nicotine products. N Engl J Med 2011;365(3):193–5.<br />
9. McCauley L, Markin C, Hosmer D. An unexpected consequence of<br />
electronic cigarette use. Chest. 2012;141(4):1110–3.<br />
www.ajpmonline.org
10. Henningfıeld JE, Zaatari GS. Electronic nicotine delivery systems:<br />
emerging science foundation for policy. Tob Control. 2010;<br />
19(2):89–90.<br />
11. Etter J-F, Bullen C, Flouris AD, Laugesen M, Eissenberg T. Electronic<br />
nicotine delivery systems: a research agenda. Tob Control. 2011;<br />
20(3):243–8.<br />
12. Etter J-F, Bullen C. Electronic cigarette: users profıle, utilization,<br />
satisfaction and perceived effıcacy. Addiction 2011;106(11):<br />
2017–28.<br />
13. Etter J-F. Electronic cigarettes: a survey of users. BMC Public Health<br />
2010;10:231–7.<br />
14. Regan AK, Promoff G, Dube SR, Arrazola R. Electronic nicotine delivery<br />
systems: adult use and awareness of the “e-cigarette” in the U.S. Tob<br />
Control. 2011. E-pub 10/27/2011.<br />
15. Pearson JL, Richardson A, Niaura RS, Vallone DM, Abrams DB. e-cigarette<br />
awareness, use, and harm perceptions in U.S. adults. Am J Public<br />
Health 2012;19:19.<br />
16. Dockrell M. What smokers tell us about e-cigarettes. UK National<br />
Smoking Cessation Conference; June; UK 2010.<br />
March 2013<br />
Adkison et al / Am J Prev Med 2013;44(3):207–215 215<br />
17. Fong GT, Cummings KM, Borland R, et al. The conceptual framework<br />
of the International Tobacco Control (ITC) Policy Evaluation Project.<br />
Tob Control 2006;15(suppl 3):iii3–iii11.<br />
18. Thompson ME, Fong GT, Hammond D, et al. Methods of the International<br />
Tobacco Control (ITC) Four Country Survey. Tob Control.<br />
2006;15(suppl 3):iii12–iii8.<br />
19. Polosa R, Caponnetto P, Morjaria JB, Papale G, Campagna D, Russ C.<br />
Effect of an electronic nicotine delivery device (e-Cigarette) on smoking<br />
reduction and cessation: a prospective 6-month pilot study. BMC<br />
Public Health 2011;11(1):786–97.<br />
20. Ayers JW, Ribisl KM, Brownstein JS. Tracking the rise in popularity of<br />
electronic nicotine delivery systems (electronic cigarettes) using search<br />
query surveillance. Am J Prev Med 2011;40(4):448–53.<br />
Supplementary data<br />
Did you know?<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
59 Acute effects of using an electronic nicotine-<br />
delivery divice
Acute effects of using an electronic nicotine-delivery<br />
device (e-cigarette) on myocardial function:<br />
comparison with the effects of regular cigarettes<br />
K. Farsalinos, D. Tsiapras, S. Kyrzopoulos, M. Savvopoulou, E. Avramidou, D.<br />
Vassilopoulou, V. Voudris<br />
Department of Cardiology, Onassis Cardiac Surgery Center, Athens, Greece<br />
Director: V. Voudris<br />
Conflict of interest: none declared
What is it?<br />
Liquid contents<br />
•Glycerol<br />
•Propylene glycol<br />
•Flavorings<br />
•Nicotine (optional)
W hy should we study it?<br />
Smoking is a major risk factor for cardiovascular disease<br />
Electronic cigarettes are used by millions of people as an alternative<br />
to smoking<br />
Interesting characteristics: nicotine delivery, dealing with<br />
psychological addiction<br />
Laboratory analysis showed that they are less toxic than cigarettes<br />
WHO has asked for clinical studies to be performed, because these<br />
products should be regulated<br />
First ever study of the effects of electronic cigarettes on<br />
cardiac function
Design<br />
Smokers<br />
N=20<br />
e-cigarette<br />
users<br />
N=22<br />
(All had quit smoking for > 1 month)<br />
Study protocol<br />
Echocardiography: GE VIVID 7, EchoPac<br />
Cigarette used: 1mg nicotine, 10mg tar, 10mg CO<br />
E-cigarette liquid used: 11mg/ml nicotine (Nobacco, USA MIX)<br />
Haemodynamic<br />
measurements<br />
+<br />
Baseline<br />
echocardiogram<br />
Smoking 1 cigarette (smokers)<br />
e-cigarette use for 7 minutes<br />
(e-cigarette users)<br />
Haemodynamic<br />
measurements<br />
+<br />
Second<br />
echocardiogram
Smoking vs electronic cigarette<br />
Results - Conclusions<br />
Haemodynamics: significant elevation in blood pressure and heart rate (+8% in<br />
systolic, +6% in diastolic, +10% in heart rate) after smoking<br />
Slight elevation of diastolic blood pressure alone (+4%) after electronic cigarette use<br />
Cardiac function: diastolic function acutely impaired in smokers (4 parameters<br />
adversely affected), in agreement with previous studies<br />
No difference in diastolic function observed after electronic cigarette use<br />
Potential mechanisms<br />
Less nicotine absorbed (Bullen at al, Tob Control 2010)<br />
Absence of combustion and different chemical composition, leading to less toxic<br />
chemicals created and absorbed<br />
Electronic cigarette may be a safer alternative to<br />
tobacco cigarettes<br />
Substituting tobacco cigarettes with electronic<br />
cigarettes may be beneficial to health
Nachschlagewerk zum Thema E-Zigaretten<br />
60 Analysis of Components from “e-Juice XX HIGH<br />
36mg/ml rated Nicotine
LPD Laboratory Services<br />
<br />
Philips Road<br />
Blackburn<br />
Lancashire, BB1 5RZ<br />
United Kingdom<br />
www.lpdlabservices.co.uk<br />
enquiries@lpdlabservices.co.uk<br />
Tel 01254-507379<br />
Fax 01254-507402
• <br />
• <br />
• <br />
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<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
©
©
© <br />
<br />
<br />
<br />
1,3-bis(3-phenoxyphenoxy) Benzene <br />
<br />
<br />
3-Cyclohexene-1-menthol,<br />
.alpha.,.alpha.4-trimethyl<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
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<br />
<br />
<br />
<br />
Glycerin <br />
Vanillin
Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic<br />
environment.<br />
These risk phrases will need to be considered in relation to the products classification under the CHIP<br />
Regulations. As the nicotine level is above 1% but under the 7% level the preparation will require to be<br />
labelled “Toxic” for health effect, but as the nicotine level is under 25% in the preparation, the preparation<br />
does not require to be labelled as “Dangerous for the environment”,<br />
<br />
<br />
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• <br />
• <br />
• <br />
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<br />
<br />
<br />
• 3-Cyclohexene-1-menthol, .alpha.,.alpha.4-trimethyl (which is an alpha-Terpinol)<br />
• Vanillin<br />
©
©
Nachschlagewerk zum Thema E-Zigaretten<br />
61 Levels of selected carcinogens and toxicants in<br />
vapour from electronic cigarettes
http://tobaccocontrol.bmj.com/content/early/2013/03/05/tobaccocontrol-2012-050859.abstract 1/2<br />
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Home > Online First > Article<br />
Tob Control doi:10.1136/tobaccocontrol-2012-050859<br />
Research paper<br />
Levels of selected carcinogens and toxicants in<br />
vapour from electronic cigarettes<br />
Maciej Lukasz Goniewicz 1,2,3 , Jakub Knysak 3 , Michal Gawron 3 , Leon Kosmider 3,4 ,<br />
Andrzej Sobczak 3,4 , Jolanta Kurek 4 , Adam Prokopowicz 4 , Magdalena Jablonska-Czapla 5 ,<br />
Czeslawa Rosik-Dulewska 5 , Christopher Havel 6 , Peyton Jacob III 6 , Neal Benowitz 6<br />
+<br />
Author Affiliations<br />
Correspondence to<br />
Dr Maciej L Goniewicz, Department of Health Behavior, Division of Cancer Prevention and<br />
Population Sciences, Roswell Park Cancer Institute, Elm & Carlton Streets / Carlton House<br />
A320, Buffalo, NY 14263, USA; maciej.goniewicz@roswellpark.org<br />
Received 24 October 2012<br />
Accepted 31 January 2013<br />
Published Online First 6 March 2013<br />
Abstract<br />
Significance Electronic cigarettes, also known as e-cigarettes, are devices designed to<br />
imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They<br />
are purported to deliver nicotine without other toxicants and to be a safer alternative to regular<br />
cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature<br />
of vapour generated from e–cigarettes. The aim of this study was to screen e-cigarette<br />
vapours for content of four groups of potentially toxic and carcinogenic compounds:<br />
carbonyls, volatile organic compounds, nitrosamines and heavy metals.<br />
Materials and methods Vapours were generated from 12 brands of e-cigarettes and the<br />
reference product, the medicinal nicotine inhaler, in controlled conditions using a modified<br />
smoking machine. The selected toxic compounds were extracted from vapours into a solid or<br />
liquid phase and analysed with chromatographic and spectroscopy methods.<br />
Results We found that the e-cigarette vapours contained some toxic substances. The levels<br />
of the toxicants were 9–450 times lower than in cigarette smoke and were, in many cases,<br />
comparable with trace amounts found in the reference product.<br />
Conclusions Our findings are consistent with the idea that substituting tobacco cigarettes<br />
with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. Ecigarettes<br />
as a harm reduction strategy among smokers unwilling to quit, warrants further<br />
study. (To view this abstract in Polish and German, please see the supplementary files<br />
online.)<br />
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Nachschlagewerk zum Thema E-Zigaretten<br />
62 Perceived efficacy of e-cigarettes versus nico-<br />
tine
Barbeau et al. Addiction Science & Clinical Practice 2013, 8:5<br />
http://www.ascpjournal.org/content/8/1/5<br />
RESEARCH Open Access<br />
Perceived efficacy of e-cigarettes versus nicotine<br />
replacement therapy among successful<br />
e-cigarette users: a qualitative approach<br />
Amanda M Barbeau * , Jennifer Burda and Michael Siegel<br />
Abstract<br />
Background: Nicotine is widely recognized as an addictive psychoactive drug. Since most smokers are biobehaviorally<br />
addicted, quitting can be very difficult and is often accompanied by withdrawal symptoms. Research<br />
indicates that nicotine replacement therapy (NRT) can double quit rates. However, the success rate for quitting<br />
remains low. E-cigarettes (electronic cigarettes) are battery-powered nicotine delivery devices used to inhale doses<br />
of vaporized nicotine from a handheld device similar in shape to a cigarette without the harmful chemicals present<br />
in tobacco products. Anecdotal evidence strongly suggests that e-cigarettes may be effective in helping smokers<br />
quit and preventing relapse, but there have been few published qualitative studies, especially among successful<br />
e-cigarette users, to support this evidence.<br />
Methods: Qualitative design using focus groups (N = 11); 9 men and 2 women. Focus groups were conducted by<br />
posing open-ended questions relating to the use of e-cigarettes, comparison of effectiveness between NRTs and<br />
e-cigarettes, barriers to quitting, and reasons for choosing e-cigarettes over other methods.<br />
Results: Five themes emerged that describe users’ perceptions of why e-cigarettes are efficacious in quitting<br />
smoking: 1) bio-behavioral feedback, 2) social benefits, 3) hobby elements, 4) personal identity, and 5) distinction<br />
between smoking cessation and nicotine cessation. Additionally, subjects reported their experiences with NRTs<br />
compared with e-cigarettes, citing negative side effects of NRTs and their ineffectiveness at preventing relapse.<br />
Conclusion: These findings suggest tobacco control practitioners must pay increased attention to the importance<br />
of the behavioral and social components of smoking addiction. By addressing these components in addition to<br />
nicotine dependence, e-cigarettes appear to help some tobacco smokers transition to a less harmful replacement<br />
tool, thereby maintaining cigarette abstinence.<br />
Keywords: Smoking, E-cigarettes, Addiction, Smoking cessation, Qualitative research, Focus group<br />
Background<br />
Nicotine is widely recognized as an addictive psychoactive<br />
drug [1]. Since most smokers are bio-behaviorally<br />
addicted, quitting can be very difficult and is often accompanied<br />
by withdrawal symptoms such as anxiety and<br />
irritability. Additionally, many smoking cessation products<br />
focus on the neuropharmacology of nicotine but fail<br />
to address the bio-behavioral component that is heavily<br />
ingrained in most addictive practices [2]. As a result,<br />
* Correspondence: abarbeau@bu.edu<br />
Department of Community Health Sciences, Boston University School of<br />
Public Health, 801 Massachusetts Avenue, 3rd Floor, Boston, MA 02118, USA<br />
smoking cessation may be unsuccessful, even when there<br />
is a strong desire to quit.<br />
Research indicates that smoking cessation medications<br />
and nicotine replacement therapy (NRT) can double quit<br />
rates [3]. However, even with the use of medications, the<br />
success rate for quitting remains low. The percentage of<br />
smokers who relapse within six months with the use of<br />
NRT is reported to be 93% [4]. Although many NRT<br />
products have been available in the US during the past<br />
decade, the overall quit rate has changed very little, from<br />
48.7% in 1998 to 51.1% in 2008 [5].<br />
E-cigarettes (electronic cigarettes) are battery-powered<br />
nicotine delivery devices. Users inhale doses of vaporized<br />
© 2013 Barbeau et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative<br />
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and<br />
reproduction in any medium, provided the original work is properly cited.
Barbeau et al. Addiction Science & Clinical Practice 2013, 8:5 Page 2 of 7<br />
http://www.ascpjournal.org/content/8/1/5<br />
nicotine from a handheld device similar in shape to a<br />
cigarette. They are also available in additional shapes,<br />
sizes, and vaporized flavors. E-cigarettes deliver nicotine<br />
without any combustion or smoke [6,7]. The recent<br />
introduction of e-cigarettes to smokers in the US presents<br />
a possible new means to enable effective smoking<br />
cessation as it addresses the biochemical and behavioral<br />
aspects of smoking addiction.<br />
One clinical trial of e-cigarettes conducted among<br />
smokers with no desire to quit reported a six-month<br />
point prevalence smoking cessation rate of 22.5% [8]. An<br />
additional 32.5% of smokers reduced their cigarette consumption<br />
by at least 50% [8]. In a previously reported<br />
survey of a sample of e-cigarette users, it was found that<br />
the six-month point prevalence of smoking abstinence<br />
was 31%, and respondents who used e-cigarettes over 20<br />
times per day had a quit rate of 70.0%—significantly<br />
higher than other smoking cessation methods [9]. Several<br />
studies have suggested that merely the presence of<br />
smoking behavioral stimuli, even in the absence of nicotine,<br />
can reduce the cravings to smoke [10,11]. A number<br />
of studies have demonstrated the efficacy of<br />
e-cigarettes in alleviating cravings for cigarettes [12,13].<br />
Evidence strongly suggests that e-cigarettes may be effective<br />
in helping smokers quit and preventing relapse,<br />
but there have been few published studies to explain<br />
why this might be the case. A recent study on<br />
e-cigarette use was conducted by interviewing individual<br />
users; key themes associated with e-cigarette use were<br />
identified, such as the culture of “vaping” and the social<br />
and informational support among the community [14].<br />
This paper reports a qualitative investigation of the effectiveness<br />
of e-cigarettes through focus group discussions<br />
among current e-cigarette users. We asked<br />
subjects to discuss their perceptions of the efficacy of<br />
e-cigarettes for smoking cessation compared to NRTs.<br />
This study adds substantially to the current literature on<br />
e-cigarettes by helping to identify hypotheses to explain<br />
the popularity of these devices and to shed light on the<br />
factors which influence the efficacy of different smoking<br />
cessation products.<br />
Methods<br />
Study design<br />
A qualitative study was conducted using focus group<br />
methodology. The study was designed to generate hypotheses<br />
regarding the factors that influence the efficacy<br />
of smoking cessation aids and to assess the sociocultural<br />
and behavioral facets of addiction that the e-cigarette<br />
may provide.<br />
Recruitment<br />
Focus groups were held with a convenience sample of 14<br />
participants recruited by posting an ad on the e-cigarette<br />
forums http://www.e-cigarette-forum.com/forum/ and<br />
www.vapersclub.com. Interested participants responded<br />
to the ad via an email address that was only accessible to<br />
study recruiters. E-cigarette users, also known as<br />
“vapers,” use these websites to discuss topics ranging<br />
from e-cigarette brand recommendations to laws about<br />
e-cigarettes. E-cigaretteforum.com has 100,000 posts a<br />
month and describes itself as the world’s largest ecigarette<br />
forum. Vapersclub.com is the website for the<br />
National Vapers Club, a consumer-based organization<br />
run and sponsored by vapers that encourages selfregulation<br />
by e-cigarette retailers until the federal government<br />
develops regulatory standards. The study’s<br />
advertisement on the websites contained an explanation<br />
of the study’s purpose, estimated time needed to participate,<br />
incentives for participation, and a contact email address.<br />
Interested individuals replied to the advertisement<br />
via a confidential email address. Potential subjects were<br />
contacted to determine eligibility for inclusion. Enrollment<br />
criteria for the focus groups included being between<br />
the ages of 18 and 64, English speaking, past smoker,<br />
current e-cigarette user, and able to travel to Boston, MA,<br />
to participate. Recruitment took place until two focus<br />
groups with 5–7 participants each had registered. This<br />
study was reviewed and approved by the Boston University<br />
Medical Campus Institutional Review Board, assigned<br />
reference number H-29473.<br />
Participants<br />
The study participants (N = 11) consisted of 9 men and<br />
2 women. There were four participants aged 18–24 years,<br />
four participants aged 25–44 years, and three participants<br />
aged 45–64 years. Nine of the participants identified<br />
themselves as non-Hispanic white. Six participants<br />
had some college or an associate degree, three had a<br />
four-year college degree, and two had a graduate degree.<br />
Their smoking histories varied. Three participants<br />
smoked for one to five years, one smoked for five to 10 -<br />
years, and six smoked from 10 to 40 years. Ten out of<br />
the 11 participants were not current users of regular cigarettes.<br />
All but two participants smoked at least a half<br />
pack of cigarettes per day before using e-cigarettes.<br />
Smoking history and exposure to e-cigarettes and other<br />
NRTs was determined by completing a survey. The survey<br />
asked a series of questions about current smoking<br />
status, smoking history, and e-cigarette and tobacco<br />
cigarette usage, in addition to asking about smoking status<br />
as of February 2010. No participants were excluded<br />
from the study due to an inability to drive to Boston, because<br />
it was clearly stated in the ad that the focus group<br />
was to take place in Boston. Thus we can reasonably assume<br />
those who could not travel to Boston to attend the<br />
focus group did not inquire about the study.
Barbeau et al. Addiction Science & Clinical Practice 2013, 8:5 Page 3 of 7<br />
http://www.ascpjournal.org/content/8/1/5<br />
Data collection<br />
Subjects read and signed a study consent form before<br />
participating in a focus group session. Participants also<br />
filled out a short anonymous survey outlining their<br />
smoking history and history of e-cigarette use. Two investigators<br />
were present at both focus groups. One investigator<br />
moderated open-ended questions relating to<br />
the use of e-cigarettes, how effective they are with quitting<br />
smoking compared with other approaches, barriers<br />
to quitting, and reasons for choosing e-cigarettes over<br />
other methods. The second investigator took notes. The<br />
focus groups were recorded with a digital voice recorder<br />
for quality assurance, and participants were assigned and<br />
referred to by numbers in order to remove personal<br />
identifiers and protect their identity. The focus group<br />
notes did not contain personal identifiers. Both focus<br />
groups lasted approximately 90 minutes.<br />
Data analysis<br />
The purpose of our study was to gain qualitative insight<br />
into whether e-cigarettes were effective aids in longterm<br />
smoking cessation and why this might be the case,<br />
in addition to gaining a greater understanding of their<br />
efficacy on reducing cravings and preventing smoking<br />
relapse. Therefore, we used grounded theory as the conceptual<br />
framework to develop theories and explanations<br />
for the data [15]. Grounded theory focuses on generating<br />
theory instead of using a particular theoretical content<br />
that focuses on an element of human experience, like<br />
culture or interpretations, to explain the data [16]. Similar<br />
to McQueen et al.’s research with vapers [14], we did<br />
not develop theories or hypotheses to explain why<br />
e-cigarettes may be effective for quitting smoking prior<br />
to conducting the research. We developed broad research<br />
questions prior to the focus groups but allowed<br />
the data to develop themes and explanations as<br />
grounded theory suggests.<br />
After the two focus group recordings were transcribed,<br />
the transcripts were coded for major themes. The two study<br />
investigators read through both transcripts separately and<br />
assigned each sentence or paragraph a descriptive and interpretive<br />
code rather than using computer software to identify<br />
themes. Investigators met to compare codes and discussed<br />
themes in order to generate theory topics to further analyze,<br />
wrote down key points that were raised in the focus groups,<br />
and then identified central themes. The coded transcripts<br />
and key point research documents were compared to ensure<br />
that all points discussed in the focus groups were acknowledged<br />
in the themes and theory developed from the data,<br />
and that all investigators agreed with the thematic outcomes.<br />
The two groups themes were concordant, and the five<br />
themes generated were observed in both groups, indicating<br />
that saturation of themes was achieved.<br />
The rationale for conducting a small focus group study<br />
was a limitation in study funding and access to<br />
e-cigarette users. This study was meant to serve as a<br />
small sampling of e-cigarette users, and the data<br />
obtained to be used to develop possible hypotheses for<br />
testing the effectiveness of e-cigarettes in larger studies.<br />
We used two focus groups instead of one because we<br />
wanted at least 10 participants and we wanted to be able<br />
to compare themes generated by two distinct groups.<br />
Results<br />
Five main themes were identified that explain why<br />
e-cigarettes appear, at least anecdotally, to be efficacious<br />
in helping tobacco users quit smoking. Table 1 provides<br />
an outline of the themes identified and some examples<br />
of narratives expressed by focus group participants illustrating<br />
those themes. Additionally, focus group members<br />
discussed the perceived efficacy of e-cigarettes compared<br />
with conventional NRTs (e.g., nicotine patch, nicotine<br />
gum).<br />
Theme: bio-behavioral feedback<br />
Participants in both focus groups felt that e-cigarette<br />
vaping mimicked smoking a real cigarette. The e-cigarette<br />
addressed participants’ oral fixation as well as the experience<br />
of inhaling, feeling the smoke hit the back of the<br />
throat (“throat hit”), and seeing the vapor cloud when exhaling.<br />
Participants emphasized the significance of the<br />
throat hit and vapor cloud, “That feeling when it comes<br />
down and hits your throat and you inhale it, that’s, like, a<br />
big deal for us all.” Additionally, the e-cigarette users<br />
followed their regular cigarette routine when vaping: “[...]<br />
When I quit cigarettes, my fixation with, you know,<br />
vaping, is very similar. So I like to vape while I’m inthe<br />
car, I like to vape after I have a meal, or when I have a coffee,<br />
or when I’m drinking, and so on; so it mirrors that,<br />
almost.” Participants explained that they were able to swap<br />
e-cigarettes into their normal everyday smoking routine.<br />
Theme: social benefits<br />
The notion of a vaping community was continually reiterated<br />
among participants. They pointed out the significance<br />
of having the online community forums where<br />
they could ask questions and find support and encouragement<br />
from fellow users. One participant shared, “Going<br />
to the website, you start hearing people’s stories [...]<br />
you research until you find something, and I kept coming<br />
back to this and really liked it. There’s a big support<br />
community ethic, which is part of it.” Another participant<br />
shared, “Having the support [from other e-cigarette<br />
users] was instrumental.” In addition to the large support<br />
network in the vaping community, enjoying the social<br />
aspect of e-cigarettes was noted. There are vaping<br />
clubs where e-cigarette users can vape together and hold
Table 1 Identified themes and examples of narratives expressed by focus group participants<br />
Themes Bio-behavioral feedback Social benefits Hobby elements Personal identity Difference<br />
between smoking<br />
cessation and<br />
nicotine cessation<br />
Narratives “That feeling when it comes down and<br />
hits your throat and you inhale it, that’s<br />
like a big deal for us all.”<br />
“[...] When I quit cigarettes, my fixation<br />
with, you know, vaping, is very similar. So<br />
I like to vape while I’m in the car, I like to<br />
vape while after I have a meal or when I<br />
have a coffee or when I’m drinking and<br />
so on, so it mirrors that almost.”<br />
“Going to the website you start hearing<br />
people’s stories [...] you research until<br />
you find something and I kept coming<br />
back to this and really liked it. There’s a<br />
big support community ethic, which is<br />
part of it.”<br />
“Having the support was instrumental.”<br />
“You don't hear about two people on the<br />
patch talking about their patches or what<br />
brand their trying or what not.”<br />
“I learned about [...] the<br />
different bases and juices.<br />
There’s so much knowledge out<br />
there and I became a nerd. And<br />
it became a hobby.”<br />
“I like all the flavors, I like the<br />
devices. You know, it’s my new<br />
hobby, my new collection. I<br />
don’t collect lighters now, I’m<br />
collecting juice and devices.”<br />
“You know, for years, I loved being able<br />
to carry around my pack of cigarettes<br />
and my Red Sox lighter. I miss carrying<br />
my Red Sox lighter [...] it becomes who<br />
you are. It becomes, you don’t do<br />
anything without a cigarette in your<br />
hand. Now I can still do that and still get<br />
the nicotine without disgusting<br />
somebody else because I am smoking,<br />
and it does stink.”<br />
“Perfect vape.” Refer to themselves as “vapers.”<br />
“When I first started,<br />
that was the plan.<br />
But I enjoy it now. I<br />
don’t see anything<br />
wrong with it.”<br />
“My goal is to be<br />
nicotine free at<br />
some point but I’m<br />
not in a hurry,<br />
either.”<br />
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discussions. As one participant mentioned, “You don’t<br />
hear about two people on the patch talking about their<br />
patches or what brand their trying or what not.” Participants<br />
enjoyed the sense of community and support from<br />
other vapers.<br />
Theme: hobby elements<br />
The participants repeatedly discussed vaping as a hobby.<br />
Most of them didn’t necessarily see e-cigarettes as a<br />
means to quit nicotine altogether but liked the experience<br />
in addition to mixing and matching different types of<br />
e-cigarette parts and “juice” flavors. One participant described<br />
it as a hobby: “I learned about [...] the different<br />
bases and juices. There’s so much knowledge out there,<br />
and I became a nerd. And it became a hobby.” Another<br />
person shared, “I like all the flavors, I like the devices. You<br />
know, it’s my new hobby, my new collection. I don’t collect<br />
lighters now, I’m collecting juice and devices.” Participants<br />
enjoyed the autonomy of playing with the different<br />
components of e-cigarette to find their “sweet spot” or<br />
“perfect vape.”<br />
Theme: personal identity<br />
The majority of participants identified themselves<br />
as “vapers.” Previously they had defined themselves as<br />
“smokers,” and the e-cigarette allowed them to redefine<br />
their identity. According to one former smoker, “You<br />
know, for years, I loved being able to carry around my<br />
pack of cigarettes and my Red Sox lighter. I miss carrying<br />
my Red Sox lighter [...] it becomes who you are. It<br />
becomes, you don’t do anything without a cigarette in<br />
your hand. Now, I can still do that and still get the nicotine<br />
without disgusting somebody else because I am<br />
smoking, and it does stink.” Instead of identifying as<br />
smokers and their brand of cigarettes, they now discuss<br />
and identify themselves by the type of e-cigarette they<br />
use and flavors they like.<br />
Theme: difference between smoking cessation and<br />
nicotine cessation<br />
As mentioned in the hobby elements theme, many of the<br />
participants did not necessarily see e-cigarettes as a means<br />
to transition to quitting nicotine altogether. Participants<br />
emphasized the difference between smoking cessation and<br />
nicotine cessation. E-cigarettes allowed them to quit<br />
smoking, but some participants did not want to quit nicotine,<br />
because they enjoy the e-cigarette experience and<br />
viewed it as going from a dangerous form of nicotine intake<br />
in cigarettes to a safer form in e-cigarettes. When<br />
asked about lowering the nicotine levels to the possibility<br />
of zero, one participant responded, “When I first started,<br />
that was the plan. But I enjoy it now. I don’t see anything<br />
wrong with it.” For those intending to eventually quit<br />
using e-cigarettes, the sense of urgency of needing to quit<br />
is not the same as with regular cigarettes. One participant<br />
shared, “My goal is to be nicotine-free at some point, but<br />
I’m notinahurry,either.” Participants also discussed how<br />
the NRTs they were familiar with (patch, gum, etc.) were<br />
meant to be temporary and to eventually wean people off<br />
of nicotine all together, whereas reducing nicotine dependence<br />
is optional with e-cigarettes.<br />
Perceived efficacy of e-cigarettes versus conventional<br />
nicotine replacement therapies<br />
In the first focus group, three of six participants had<br />
tried varenicline, four of six had tried nicotine gum, and<br />
five of six had tried the nicotine patch. In the second<br />
focus group, participants expressed little confidence in<br />
the perceived efficacy of conventional NRTs, claiming<br />
that they still found themselves craving cigarettes while<br />
using these methods. They also reported undesirable<br />
side-effects and many quit attempts using NRTs that<br />
resulted in relapse to cigarette use. One participant<br />
reported that, while on the patch, “If you’re asking what<br />
do we mean when we say the patches didn’t work, at a<br />
certain point in time I was having a cigarette after; so<br />
whether it was a failure of the patch, or psychological, or<br />
with me or us, it does seem at the end of the day or end<br />
of the month you’re back on the cigarettes.” Another<br />
participant reported that the patch satiated the physiological<br />
craving for nicotine but not the psychological:<br />
“[...] The patch was able to satisfy the physical craving<br />
for me. It’s the psychological craving.”<br />
Negative side-effects were reported during the use of<br />
NRTs. Some claimed to experience negative side-effects<br />
with the gum and the patch, with one participant suffering<br />
from hiccups during the use of the gum: “You get<br />
the hiccups. You feel your heart going like crazy.” Others<br />
reported extremely disturbing dreams while taking<br />
varenicline. One participant even claimed to smoke cigarettes<br />
while using varenicline: “I smoked through the<br />
whole thing. I was just smoking and taking varenicline.”<br />
When asked how e-cigarettes compare with traditional<br />
NRTs, one participant stated, “It’s the only thing that<br />
ever worked. I think it’s part the act. I think its part the<br />
way it’s delivered.” And another, speaking about NRTs,<br />
stated, “The delivery doesn’t work, that’s what I learned.<br />
Plain and simple.”<br />
Discussion<br />
Results from these focus groups add to the albeit still<br />
limited research base regarding e-cigarettes and their<br />
usefulness as smoking cessation tools. The information<br />
gained provides new insights into the social and group<br />
dynamics that may underlie the reasons why NRT has<br />
such low observed rates of effectiveness, and why<br />
e-cigarettes, at least anecdotally, appear to be more<br />
effective for many vapers. Most notably, these include
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e-cigarettes becoming part of the vaper’s social identity,<br />
the recognition of vaping as a hobby, and the ability of<br />
these devices to aid in smoking cessation without complete<br />
nicotine cessation.<br />
These insights suggest that health practitioners should pay<br />
increased attention to the behavioral and social components<br />
of smoking addiction, many of which are not addressed by<br />
conventional NRTs, as noted by participants in this study.<br />
Greater understanding of these components could lead to<br />
more effective approaches to treating cigarette addiction, as<br />
the e-cigarette users in our focus groups experienced alleviation<br />
of withdrawal symptoms and achieved smoking cessation<br />
more effectively than they had with conventional NRT.<br />
The ability for e-cigarette users to redefine themselves<br />
from “smokers” to “vapers” could be incredibly useful<br />
not only in helping tobacco smokers transition to a less<br />
harmful replacement tool but also in helping them<br />
maintain cigarette abstinence. Many participants in the<br />
focus groups reported having relapsed multiple times<br />
using the patch, nicotine gum, and prescription medications.<br />
This sense of identity as a vaper, both on an individual<br />
and group level, appears to give e-cigarette users<br />
a sense of ownership over their cigarette addiction. This<br />
identity also appeared to be formed and reinforced<br />
through the support provided by e-cigarette online forums,<br />
where e-cigarette users exchanged information,<br />
displayed pride over number of days cigarette-free, and<br />
received encouragement for quitting [14].<br />
E-cigarette use being described as a hobby suggests that<br />
the experience is enjoyable and that having a variety of<br />
flavors, devices, and nicotine levels available reinforces the<br />
motivation to quit smoking and helps prevent relapse. However,<br />
due to this variety, further investigation into the concept<br />
of the learning curve that occurs with e-cigarette use is<br />
warranted.<br />
Both groups emphasized the difference between smoking<br />
cessation and nicotine cessation and viewed the e-cigarette<br />
as being a safer form of nicotine delivery. Participants recognized<br />
that their addiction to nicotine had not subsided, but<br />
the means for nicotine administration was replaced by a perceived<br />
safer alternative.<br />
The perceptions of e-cigarette users towards vaping as<br />
compared to smoking are relevant to legal and policy considerations<br />
regarding these products. The subjects in our<br />
study clearly viewed e-cigarettes as both a tool for smoking<br />
cessation and a safer alternative to cigarettes. However, the<br />
current legal and policy framework surrounding e-cigarettes<br />
precludes their being marketed with claims that they are<br />
safer than regular cigarettes or that they may be useful in<br />
smoking cessation. The former claim might be considered a<br />
reduced-risk claim under the Family Smoking Prevention<br />
and Tobacco Control Act [17], and the latter might be considered<br />
a therapeutic claim, which would put the product<br />
under the scrutiny of the US Food, Drug, and Cosmetic Act<br />
[18]. Ironically, although e-cigarettes contain no tobacco, the<br />
courts have ruled that these products must be regulated as<br />
tobacco products rather than as drugs [19]. The way<br />
in which actual users of e-cigarettes perceive these products<br />
should be considered by the US Food and Drug<br />
Administration, which is currently developing regulations<br />
for e-cigarettes.<br />
This study was limited in that the sample of participants<br />
was not representative of all e-cigarette users; they<br />
were recruited from only two online forums and included<br />
only participants who were willing and able to<br />
drive to the focus group location. Furthermore, the sample<br />
represents e-cigarette users who were committed<br />
and involved enough with e-cigarettes to be on these<br />
forums. This presents an inherent bias in the sample, as<br />
those who participated in the focus groups likely favored<br />
e-cigarettes for smoking cessation. Therefore, the information<br />
gained within the focus groups may not be<br />
generalizable to e-cigarette users overall, and this inherent<br />
bias could lead to an overestimation of the successful<br />
use of e-cigarettes as smoking cessation tools. Although<br />
it is true that sampling bias exists, we do not believe this<br />
threatens the validity of our conclusions, as this study<br />
was intended to bring to light how e-cigarettes are perceived<br />
among those who have found them helpful.<br />
Further research with larger sample sizes from multiple<br />
sites would yield a greater representation of the<br />
e-cigarette user population, as would the inclusion of<br />
previous e-cigarette users who relapsed.<br />
Conclusion<br />
There is anecdotal evidence that e-cigarettes may be<br />
useful in helping smokers quit, but little is known about<br />
the reasons why these products help smokers achieve<br />
cessation or how smokers perceive these products in<br />
comparison to other cessation strategies such as traditional<br />
NRTs. We conducted focus groups with<br />
e-cigarette users to assess their perceptions of the efficacy<br />
of these devices in smoking cessation compared<br />
with other strategies such as varenicline, nicotine gum,<br />
and the nicotine patch. We identified five major themes<br />
to explain why e-cigarettes appear to be helpful in aiding<br />
cessation, at least for some users. These themes highlight<br />
the need for health practitioners and policy makers<br />
to give greater consideration to the physical, behavioral,<br />
and social aspects of cigarette smoking addiction and<br />
not merely to treat smoking addiction as a pharmacologic<br />
addiction to nicotine.<br />
Competing interests<br />
The authors declare that they have no competing interests.<br />
Authors’ contributions<br />
All authors participated in the conception of the study and in crafting the<br />
research design. AB and JB prepared the IRB protocol, conducted the focus<br />
group sessions, and analyzed the focus group transcripts. All authors
Barbeau et al. Addiction Science & Clinical Practice 2013, 8:5 Page 7 of 7<br />
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participated in the review and interpretation of the data, the preparation of<br />
the manuscript, and the review of the manuscript for critical content. All<br />
authors read and approved the final manuscript.<br />
Acknowledgments<br />
We would like to thank Dr. Michael Siegel for his support and advisement<br />
throughout the process of conducting the research for this paper.<br />
Received: 22 May 2012 Accepted: 1 March 2013<br />
Published: 5 March 2013<br />
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Cite this article as: Barbeau et al.: Perceived efficacy of e-cigarettes<br />
versus nicotine replacement therapy among successful<br />
e-cigarette users: a qualitative approach. Addiction Science & Clinical<br />
Practice 2013 8:5.<br />
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