Legaliseringsguiden, genomgång av ... - PDF Archive

there is a greater respiratory burden of carbon monoxide and smoke
particulates such as tar than when smoking a similar quantity of tobacco.
Cannabis smoking is likely to weaken the immune system. Infections of the
lung are due to a combination of smoking-related damage to the cells lining
the bronchial passage (the fine hair-like projection on these cells filter out
inhaled microorganisms) and impairment of the principal immune cells in
the small air sacs caused by cannabis.
The evidence concerning a possible link between cannabis smoking and
Chronic Obstructive Pulmonary Disease (COPD) has not yet been
conclusively established. A number of studies indicate a causal relationship
between the two whereas others contradict these findings.
Research linking cannabis smoking to the development of respiratory cancer
exists although there have also been conflicting findings. Not only does the
tar in a cannabis cigarette contain many of the same known carcinogens as
tobacco smoke but the concentrations of these are up to 50% higher in the
smoke of a cannabis cigarette. It also deposits four times as much tar on the
respiratory tract as an unfiltered cigarette of the same wieght. Smokers of
cannabis and tobacco have shown a greater increase in cellular
abnormalities indicating a cumulative effect of smoking both.
The THC in cannabis has been shown to have a short term bronchodilator
effect. This has lead to suggestions that THC may have therapeutic benefits
in asthma. However, the noxious gases, chronic airway irritation or
malignancy after long term use associated with smoking would seem likely
to negate these benefits.
— British Lung Foundation - A Smoking Gun [12]
Kritik av studien kan läsas här: UKCIA critique of the BLF report "A smoking gun"
En genomgång av litteraturen kring cannabis och lungproblem [13] som publicerades 2010 av engelska
forskare ger också stöd för att lungproblemen existerar. Det kan dock riktas kritik mot källorna som
anges och därmed resultatet, det handlar om många gamla Tashkin-studier och Aldingtons från 2008
(vi kommer till den).
Det finns ett par studier från Nordafrika som indikerar en högre cancerrisk för cannabisrökare, en från
Marocko mellan 1996-1998 [14] och en från Tunisien 1988-1989 [15] . En granskning av bl.a Tashkin visar
brister i forskningen:
An eightfold increase in risk among marijuana users was observed in a lung cancer
study in Tunisia. However, there was no assessment of the dose response, and
marijuana may have been mixed with tobacco
“
... The two lung cancer studies with assessment of marijuana use as a possible risk
factor were conducted in North Africa. Hsairi et al. (1993) reported a highly elevated
OR for ever use of cannabis in a case–control study in Tunisia, including 110 lung
cancer cases and 110 control subjects (OR 5 8.2, 95% CI 5 1.3-15.5). Dose-response
relations for frequency and duration of marijuana use were not assessed. The
amount of marijuana and tobacco used among these subjects would be of great
interest to know because marijuana is thought to be used in larger amounts, and
together with tobacco, in this region. Sasco et al. (2002) studied hashish and kiff use
in Morocco in a case–control study, including 118 lung cancer cases and 235 control
subjects. Kiff (or kif), prevalent in Northern Morocco, is a preparation of powder
from the dried flower of the female Cannabis sativa plant mixed with tobacco (Nahas
et al., 1975). They reported an increased risk of lung cancer for subjects who used
hashish/kiff and snuff (OR 5 5.64, 95% CI 5 1.55-20.54), but results were less clear
for subjects who used hashish/kiff without snuff (OR 5 1.99, 95% CI 5 0.63-6.30) and
subjects who used snuff only (OR 5 1.06, 95% CI 5 0.33-3.47). A possible explanation
for the observed association may be that this category captured subjects who used
hashish/kiff and snuff at higher durations and frequencies. Because kiff includes
tobacco, the independent effect of marijuana cannot be assessed in this study.
— Hashibe, 2005 [16]
”
364