Abstract: We included 17 observational studies in this review. We found no randomized controlled trials. Twelve studies are based in hospitals, three in prisons and two in universities. Three studies used a controlled before-and-after design, with another site used for comparison. The remaining 14 studies used an uncontrolled before-and-after study design. Five studies reported evidence from two participant groups, including staff and either patients or prisoners (depending on specialist setting), with the 12 remaining studies investigating only one participant group. The four studies (two in prisons, two in hospitals) providing health outcomes data reported an effect of reduced secondhand smoke exposure and reduced mortality associated with smoking-related illnesses. No studies included in the review measured cotinine levels to validate secondhand smoke exposure. Eleven studies reporting active smoking rates with 12,485 participants available for pooling, but with substantial evidence of statistical heterogeneity (I² = 72%). Heterogeneity was lower in subgroups defined by setting, and provided evidence for an effect of tobacco bans on reducing active smoking rates. An analysis exploring heterogeneity within hospital settings showed evidence of an effect on reducing active smoking rates in both staff (risk ratio (RR) 0.71, 95% confidence interval ( CI) 0.64 to 0.78) and patients (RR 0.86, 95% CI 0.76 to 0.98), but heterogeneity remained in the staff subgroup (I² = 76%). In prisons, despite evidence of reduced mortality associated with smoking-related illnesses in two studies, there was no evidence of effect on active smoking rates (1 study, RR 0.99, 95% CI 0.84 to 1.16). We judged the quality of the evidence to be low, using the GRADE approach, as the included studies are all observational. We found evidence of an effect of settings-based smoking policies on reducing smoking rates in hospitals and universities. In prisons, reduced mortality rates and reduced exposure to secondhand smoke were reported. However, we rated the evidence base as low quality. We therefore need more robust studies assessing the evidence for smoking bans and policies in these important specialist settings.

Plain-language summary: Studies have shown that workplaces providing services to help smokers to stop smoking have been effective. Services can include providing nicotine replacement therapy (NRT) and counselling support to help smokers quit. However, it is not known if policies that stop people smoking in institutions are effective. Whilst smoking is banned in many public places, it is not banned in all of them. Smoking is allowed in some healthcare organisations, universities and prisons. Study characteristics We searched for studies that measured whether introducing a smoking policy or ban, in hospitals, universities or prisons, reduced secondhand smoke exposure and helped people to quit smoking. The study could be in any language. It had to report information on health and smoking before the policy or ban started and for at least six months afterwards. We have included 17 studies in this review. Twelve studies provide evidence from hospitals, three from prisons and two from universities. The evidence is up-to-date to June 2015. Key results We grouped together 11 of the included studies, involving 12,485 people, and found that banning smoking in hospitals and universities increased the number of smoking quit attempts and reduced the number of people smoking. In prisons, there was a reduction in the number of people who died from diseases related to smoking and a reduction in exposure to secondhand smoke after policies and bans were introduced, but there was no evidence of reduced smoking rates. Quality of the evidence We found no relevant high-quality studies to include in our review. Future high-quality research may lead to a change in these conclusions and it is not possible to draw firm conclusions from the current evidence. We need more research from larger studies to investigate smoking bans and policies in these important settings.