Legislative smoking bans for reducing secondhand smoke exposure ...

participants and outcomes for each study. No randomized controlled
trials were identified. Twenty four studies included cohort
follow up pre and post ban, in working populations, 18 studies
comprised repeated cross-sectional measures mainly in general
populations and 13 studies were quasi-experimental in design, in
that they included a reference area. By tracking the same people
over time, a longitudinal cohort is not affected by extraneous, between
examination, confounders.
The studies examined the effect of clean indoor air legislation
implemented in countries, states and regional areas. The effect
of the implementation of smoking ban legislation was considered
in 13 different countries. Seventeen studies were in United States
of America, eight in Scotland, five in Ireland, four in Italy, three
each in Spain and Norway, two each in New Zealand, Canada and
Finland, and one each in France, England, the Netherlands and
Sweden.
Legislative smoking bans vary in the extent to which they allow
smoking or restrict it to designated areas. For this review, legislation
which prohibits smoking in indoor workplaces, including
bars and restaurants, is categorised as comprehensive, even though
it may allow exemptions in particular settings e.g. prisons, or psychiatric
and mental health settings. Legislation which allows designated
smoking areas in indoor workplaces, including bars and
restaurants, is categorised as a partial ban. Ten studies (Alcouffe
1997; Bondy 2009; Brownson 1995; Fernández 2009; Galán
2007; Gallus 2007; Heloma 2003; Khuder 2007; Jiménez-Ruiz
2008; Verdonk-Kleinjan 2009) examined the effects of less restrictive
legislation which did not prohibit smoking in bars and restaurants,
and are categorised as partial ban studies. The remaining
studies are categorised as comprehensive bans.
Twenty-two studies were concerned with reduction of workplace
exposure, nineteen of which were concerned with hospitality workers.
Measures of passive exposure considered in these studies were
self-reported exposure in general - at work or at home or in cars,
biomarker verification, and prevailing air quality.
Measures of active smoking considered were smoking prevalence
rates, tobacco consumption and smoking cessation. Health outcome
measures considered were respiratory and sensory symptomatology,
cardiovascular events, including hospital admission
rates for acute coronary syndrome or myocardial infarction.
Risk of bias in included studies
See Characteristics of included studies for a summary of the
methodological characteristics.
Study design
The predominant type of study design was uncontrolled beforeand-after
studies, either with cohort follow up or repeated crosssectional
surveys. We found no randomized controlled trials where
the primary intervention was a smoking ban. Thirteen quasi-experimental
studies included a reference area with intervention and
control conditions but non-randomly allocated, seven in a general
or workplace setting (Allwright 2005; Biener 2007; Bondy 2009;
Fernández 2009; Fong 2006; Hahn 2008; Hyland 2009), and six
which were concerned with hospital admissions (Bartecchi 2006;
Fichtenberg 2000; Khuder 2007; Pell 2008; Sargent 2004; Seo
2007). All the remainder were uncontrolled studies with baseline
measures and at least one or two post-ban assessments, including
one study with three post-ban follow-up surveys (Farrelly 2005).
Blinding
Study investigators and participants could not be blinded since
the introduction of legislation was public knowledge and was associated
with a highly visible health behaviour . In one study the
assessors measuring cotinine concentration were blinded as to the
smoking status of the participants (Fernández 2009).
Selection of participants
Random sampling was used to select the participants in 16
studies (Biener 2007; Braverman 2008; Brownson 1995; CDC
2007; Eagan 2006; Fong 2006; Fowkes 2008; Gallus 2007;
Gilpin 2002; Hahn 2008; Haw 2007; Hyland 2009; Jiménez-Ruiz
2008; Lemstra 2008; Mullally 2009; Verdonk-Kleinjan 2009;).
In five studies the method of selection was unclear or not reported
(Akhtar 2007; Alcouffe 1997; Cesaroni 2008; Galán 2007;
Palmersheim 2006). Eleven studies used a convenience sample
(Abrams 2006; Bondy 2009; Ellingsen 2006; Farrelly 2005;
Fernández 2009; Goodman 2007; Gotz 2008; Heloma 2003;
Larsson 2008; Menzies 2006; Mulcahy 2005), with all but Abrams
2006 and Heloma 2003 set in the hospitality sector. In six studies
the bars were randomly selected for inclusion and their employees
were invited either to participate (Eisner 1998; Fernando 2007;
Hahn 2006; Pearson 2009; Semple 2007) or a mixture of random
and convenience sampling was used (Allwright 2005) to select
pubs in the intervention and control communities respectively.
In Waa 2006, a random sample of participants was selected from
the pre-ban cross-sectional surveys, and a convenience sample was
used in the follow-up surveys. In one study, the assessors had to
go through the entire list of randomized bars many times in order
to achieve adequate sample size (Pearson 2009).
Comparability of intervention and control
communities at baseline
Eight of the quasi-experimental studies described the demographic
characteristics of participants in the control and intervention conditions
at baseline (Allwright 2005; Bartecchi 2006; Biener 2007;
Bondy 2009; Fernández 2009; Fong 2006; Hahn 2008; Seo 2007).
Legislative smoking bans for reducing secondhand smoke exposure, smoking prevalence and tobacco consumption (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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