To investigate trends in smoking cessation before and after the introduction of Scottish smoke-free legislation and to assess the perceived influence of the legislation on giving up smoking and perceptions of the legislation in smokers.

Longitudinal data on smoking cessation were obtained from 1998 to 2007 on a cohort of 3350 Scottish adults aged between 50 and 75 years at baseline. All members of the cohort were participating in a clinical trial of aspirin in people at moderately increased risk of cardiovascular events. A subgroup of 474 participants who had smoked in the year prior to the introduction of legislation in March 2006 also completed a questionnaire on the influence and perceptions of the smoke-free legislation following its introduction.

Smoking status was recorded yearly, including dates of quitting and restarting. Participants who gave up smoking for at least 3 months were recorded as having quit smoking. The questionnaire included scales on whether the smoke-free legislation had helped/influenced cessation, made the individual think about/prompt them to quit and perceptions of the legislation.

The odds of smokers quitting annually increased throughout the 7-year period prior to introduction of the smoke-free legislation to 2 years afterwards (odds ratio 1.09, 95% confidence interval 1.05-1.12, P<0.001). During 2006, the pattern of quarterly quitting rates changed, with an increase in quit rates (to 5.1%) in the 3-month period prior to introduction of the legislation (January-March 2006). Socio-economic status was not related to smoking cessation. In the subgroup completing the questionnaire (n=474), 57 quit smoking between June 2005 and May 2007 and 43.9% of these said that the smoke-free legislation had helped them to quit. Most (>70%) smokers were positive about the legislation, especially those from more affluent compared with more deprived communities (P=0.01).

The Scottish smoke-free legislation was associated with an increase in the rate of smoking cessation in the 3-month period immediately prior to its introduction. Overall quit rates in the year the legislation was introduced and the subsequent year were consistent with a gradual increase in quit rates prior to introduction of the legislation. Socio-economic status was not related to smoking cessation, but individuals from more affluent communities were more positive about the legislation.