Legislative smoking bans for reducing harms from secondhand smoke exposure, smoking prevalence and tobacco consumption

Background Smoking bans have been implemented in a variety of settings, as well as being part of policy in many jurisdictions to protect the public and employees from the harmful effects of secondhand smoke (SHS). They also offer the potential to influence social norms and the smoking behaviour of those populations they affect. Since the first version of this review in 2010, more countries have introduced national smoking legislation banning indoor smoking. Objectives To assess the effects of legislative smoking bans on (1) morbidity and mortality from exposure to secondhand smoke, and (2) smoking prevalence and tobacco consumption. Search methods We searched the Cochrane Tobacco Addiction Group Specialised Register, MEDLINE, EMBASE, PsycINFO, CINAHL and reference lists of included studies. We also checked websites of various organisations. Date of most recent search; February 2015. Selection criteria We considered studies that reported legislative smoking bans affecting populations. The minimum standard was having an indoor smoking ban explicitly in the study and a minimum of six months follow‐up for measures of smoking behaviour. Our search included a broad range of research designs including: randomized controlled trials, quasi‐experimental studies (i.e. non‐randomized controlled studies), controlled before‐and‐after studies, interrupted time series as defined by the Cochrane Effective Practice and Organisation of Care Group, and uncontrolled pre‐ and post‐ban data. Data collection and analysis One author extracted characteristics and content of the interventions, participants, outcomes and methods of the included studies and a second author checked the details. We extracted health and smoking behaviour outcomes. We did not attempt a meta‐analysis due to the heterogeneity in design and content of the studies included. We evaluated the studies using qualitative narrative synthesis. Main results There are 77 studies included in this updated review. We retained 12 studies from the original review and identified 65 new studies. Evidence from 21 countries is provided in this update, an increase of eight countries from the original review. The nature of the intervention precludes randomized controlled trials. Thirty‐six studies used an interrupted time series study design, 23 studies use a controlled before‐and‐after design and 18 studies are before‐and‐after studies with no control group; six of these studies use a cohort design. Seventy‐two studies reported