Results of outdoor smoking bans at secondary schools on adolescents smoking behaviour: a quasi-experimental study

Background: Research on the effectiveness of school smoking policies on adolescents' smoking behaviour remain inconclusive. This study evaluates the results of an outdoor school ground smoking ban at secondary schools on adolescents smoking behaviour, taking individual characteristics into account. Methods: Data on 2684 adolescents from 18 Dutch secondary schools (nine with and nine without an outdoor smoking ban) were obtained at two moments. Associations between outdoor school ground smoking bans, individual characteristics, and smoking prevalence and frequency were measured. Multilevel logistic regression analyses were used. At schools with a ban implementation fidelity was checked. Results: Although smoking prevalence and frequency appeared to make a slower increase at schools with an outdoor smoking ban compared with schools without an outdoor smoking ban, the differences were not significant. Differences between schools in the prevalence of smoking behaviour of students could mainly be explained by individual characteristics. Smoking prevalence and frequency were higher among adolescents with a positive attitude towards smoking and when significant others were more positive about smoking. Smoking prevalence and frequency were significantly lower when adolescents perceived it as easy not to smoke. Implementation fidelity was good at schools with a ban. Conclusions: No short-term effects were found of an outdoor smoking ban. A longer follow-up time than 6 months is needed. In addition, future research should investigate effectiveness in relation to the enforcement of the ban, comprehensiveness of the ban and when it is prohibited to leave school grounds, as smoking behavior might be transferred off school grounds.