|| Checking for direct PDF access through Ovid
In Germany, the smoking prevalence among adolescents is among the highest in Europe. Our aim was to evaluate the long-term effectiveness of a combined student–parent and a student-only smoking prevention programme to reduce the smoking prevalence among 7th grade students in Berlin.Three-armed cluster-randomized controlled trial (RCT). Schools as cluster units were randomized into (i) student intervention, (ii) combined student–parent intervention or (iii) control group, with follow-up after 12 and 24 months.High schools and integrated secondary schools in Berlin, Germany.Seventh grade students aged 11–16 years. We included 47 schools, 161 classes and 2801 students [50.1% girls, mean age ± standard deviation (SD) = 13.0 ± 0.6 years].The primary outcome was self-reported regular smoking (at least one cigarette per day) after 24 months (point prevalence). Further self-reported outcomes were other smoking behaviours as well as parental rules and attitudes towards smoking. Comparisons were calculated as odds ratios (OR) with 95% confidence intervals (CI).At baseline, 2.3% of the students reported that they smoked regularly. After 24 months, 7.8% and 7.0% were regular smokers in the student–only intervention and the student–parent intervention, respectively, compared with 10.1% in the control group. The OR for being a regular smoker was 0.81 (0.34–1.92) for the student–parent intervention versus control, 0.95 (CI = 0.41–2.22) for the student-only intervention versus control and 0.85 (0.38–1.89) for student–parent intervention versus student-only intervention.A combined student–parent smoking prevention intervention delivered via secondary schools in Berlin, Germany did not result in a statistically significant reduction in regular smoking compared with a control group or a student-only intervention. The student-only intervention did not result in a significant reduction in regular smoking compared with the control group.