Effectiveness of the "Smoke-Free Class Competition" in delaying the onset of smoking in adolescence. Effects of Smokefree Class Competition 1 year after the end of intervention: a cluster randomised controlled trial. Prevention of smoking in adolescents with lower education: a school based intervention study. Adverse effects of a social contract smoking prevention program among children in Québec, Canada. Lack of sustainable prevention effect of the "Smoke-Free Class Competition" on German pupils.
This paper examines the effectiveness of the "Smoke-Free Class Competition" in delaying the onset of smoking in adolescence. Each participating class must decide if they want to be a "smoke-free class" for the 6-month period from fall to spring. Classes monitor their (non-)smoking behavior and report it to the teacher regularly. Classes in which pupils refrain from smoking for this period of time participate in a prize draw, in which they can win a number of attractive prizes.
                To evaluate the effectiveness of the competition, a sample of 131 participating and nonparticipating classes (number of pupils 2,142; mean age 12.9 years, SD = 0.98) was compared with regard to their smoking behavior. Smoking status was determined by self-assessment on three occasions: (a) prior to the beginning of the competition, (b) 1 month after the competition, and (c) 1 year after the start of the competition.
                From pretest to posttest smoking increased by 7.5% in the comparison group, while it decreased by 0.2% in the intervention group (OR = 2.19; P < 0.001). In the follow-up measurement, a clear increase in smoking prevalence occurs in all groups; however, the pupils in the intervention condition still have a significant lower increase of smoking (OR = 1.45; P < 0.01). Moreover, with regard to the nonsmokers at baseline, pupils in the comparison group showed significantly higher prevalences in smoking than the intervention group in the postmeasurement, 7.8 versus 13.9% (OR = 1.98; P < 0.001), as well as in the in the follow-up-measurement, 17 versus 21.3% (OR = 1.36; P < 0.05).
                The results suggest that the participation in the competition could delay the onset of smoking in adolescence. The Smokefree Class Competition, a school-based smoking prevention intervention, is widely disseminated in Europe. Participating classes commit themselves to be smoke-free and self-monitor their smoking status. Classes that remain smoke-free for 6 months can win prizes. Effects of the intervention on current smoking, initiation and progression of smoking were investigated.
                Cluster randomised controlled trial. 84 schools (208 classes with 3490 students; mean age 12.6 years, 50.4% female) in Saxony-Anhalt, Germany, were randomly assigned to intervention or control condition. A baseline survey was conducted before the implementation of the programme, while post-test and follow-up surveys were carried out 7 (immediately after the end of the competition), 12 and 19 months after baseline. Effects of participation in the programme on current and lifetime smoking were analysed by multilevel models controlling for confounding variables.
                Intervention students smoking occasionally at baseline smoked less frequently than students taking not part in the intervention at 7 and 12 months after baseline. Persistent beneficial programme effects were also found for lifetime smoking: intervention students were less likely to progress from experimental to established use.
                Data suggest that Smokefree Class Competition reduces the probability of progressing from occasional and experimental stages of smoking to more established forms of use.
                Trial registration ISRCTN27091233 in Current Control Trial Register. To assess the effect of an antismoking intervention focusing on adolescents in lower education. Students with lower education smoke more often and perceive more positive norms, and social pressure to smoke, than higher educated students. An intervention based on peer group pressure and social influence may therefore be useful to prevent smoking among these students.
                Group randomised controlled trial.
                26 Dutch schools that provided junior secondary education.
                1444 students in the intervention and 1118 students in the control group, all in the first grade, average age 13 years.
                Three lessons on knowledge, attitudes, and social influence, followed by a class agreement not to start or to stop smoking for five months and a class based competition.
                Comparison of smoking status before and immediately after and one year after the intervention, using multilevel analysis.
                In the intervention group, 9.6% of non-smokers started to smoke, in the control group 14.2%. This leads to an odds ratio of 0.61 (95% CI= 0.41 to 0.90) to uptake smoking in the intervention group compared with the control group. One year after the intervention, the effect was no longer significant.
                In the short-term, an intervention based on peer pressure decreases the proportion of adolescents with lower education who start smoking. Influencing social norms and peer pressure would therefore be a promising strategy in terms of preventing smoking among adolescents. The results also suggest that additional interventions in later years are needed to maintain the effect. To evaluate the impact of a smoke-free class competition in elementary schools in Québec, Canada before widespread dissemination of the program across the province.
                In a quasiexperimental study design, 843 students in 27 schools exposed to "Mission TNT.06" were compared to 1213 students in 57 matched comparison schools. Baseline data were collected in grade 6 prior to implementation of the program. Follow-up data were collected in grade 7 after students had transitioned to secondary school.
                The program improved knowledge about the harmful effects of second-hand smoke, but had no impact on knowledge about the harmful effects of smoking, attitudes about the acceptability of cigarettes, beliefs about the tobacco industry, or self-efficacy to resist peer pressure to smoke. After exposure to the program, intervention students were more likely to misreport their smoking status and to report unfavourable attitudes about classmates who smoke.
                Mission TNT.06 may encourage young smokers to misreport their smoking status and to marginalise classmates who smoke. These findings prompted recommendations to conduct more in-depth evaluation of the smoke-free class competition before widespread dissemination of the program across the province. This study examines the effectiveness of the school-based campaign "Smoke-Free Class Competition" as a means of preventing young non-smokers from taking up smoking.
                Based on two measurements of the Heidelberg Children's Panel Study (1998 and 2000), a longitudinal sample of 1704 pupils was examined: 948 in the intervention group and 756 in the control group. In order to evaluate the effects of the intervention, we compared the smoking behavior in the intervention and the control group at two points in time, shortly before, and 18 months after the intervention, on an individual case basis.
                (1) Stabilization of never-smoking rates: the proportion of pupils remaining a never-smoker at the follow-up is 62.1% in the intervention group and 61.5% in the control group (OR 1.02, 95% CI: 0.83-1.24); (2) Lowering of relapse rates among ex-smokers: the proportion of former smokers who had not started smoking again in the follow-up is 45.1% in the intervention group and 41.4% in the control group (OR 1.07, 95% CI: 0.77-1.49).
                The "Smoke-Free Class Competition" did not prevent smoking among adolescents and does not appear to be an effective substitute to the complete ban of tobacco advertising, the abolition of vending machines and the creation of smoke-free environments in German schools.
To date, incentive programmes have not been shown to prevent smoking initiation among youth, although there are relatively few published studies and these are of variable quality. Trials included in this meta-analysis were all studies of the SFC competition, which distributed small to moderately sized prizes to whole classes, usually through a lottery system. 
Future studies might investigate the efficacy of incentives given to individual participants to prevent smoking uptake. Future research should consider the efficacy of incentives on smoking initiation, as well as progression of smoking, evaluate these in varying populations from different socioeconomic and ethnic backgrounds, and describe the intervention components in detail.