School smoking policies and smoking prevalence among adolescents: multilevel analysis of cross-sectional data from Wales

Objective-To examine the association between school smoking policies and sm oking prevalence among pupils. Design-Multilevel analysis of cross-sectional data from surveys of schools and pupils. Setting-55 secondary schools in Wales. Subjects-55 teachers and 1375 pupils in year Il(aged 15-16). Main outcome measures-Self-reported smoking behaviour. Results-The prevalence of daily smoking in schools with a written policy on smoking for pupils, teachers, and other adults, with no pupils or teachers allowed to smoke anywhere on the school premises, was 9.5% (95% confidence interval (CI) 6.1% to 12.9%). In schools with no policy on pupils) or teac hers' smoking, 30.1% (95% CI 23.6% to 36.6%) of pupils reported daily smoki ng. In schools with an intermediate level of smoking policy, 21.0% (95% CI 17.8% to 24.2%) smoked every day. School smoking policy was associated with school level variation in daily smoking (p = 0.002). In multilevel analysi s, after adjusting for pupils' sex, parents) and best friends' smoking stat us, parental expectations, and alienation from school, there was less unexp lained school level variation, but school smoking policy remained significa nt (p = 0.041). The association of smoking policy with weekly smoking was w eaker than for daily smoking, and not significant after adjustment for pupi l level variables. Both daily and weekly smoking prevalence were lower in s chools where pupils' smoking restrictions were always enforced. Enforcement of teacher smoking restrictions was not significantly associated with pupi ls' smoking. Conclusions-This study demonstrates an association between policy strength, policy enforcement, and the prevalence of smoking among pupils, after havi ng adjusted for pupil level characteristics. These findings suggest that th e wider introduction of comprehensive school smoking policies may help redu ce teenage smoking.