QUESTION

Do school-based programmes prevent tobacco smoking in children and young people?

RELEVANCE TO NURSING CARE

The main preventable risk factor for mortality and morbidity worldwide is tobacco smoking (in forms such as cigarette and water pipe use); a potential 20% reduction in death rates could be achieved if people did not use tobacco. It is known that if children or young people start to smoke they may become regular smokers in later life and have difficulty quitting. The younger a child is when they start to smoke, the more likely they are to continue to regularly smoke in adulthood. School-based programmes provide an opportunity to engage the majority of children and young people worldwide in health promotion.

There are five types of smoking prevention curricular strategies that school-based programmes can offer: information-only education to provide accurate facts to pupils, social competence support to reduce personal susceptibility through developing skills such as self-control and esteem, social influence training to build resistance against peer pressure and learn tobacco refusal skills, combined social competence and influence approaches and multimodal interventions (which integrate training with initiatives in school policy, parental and/or community involvement). As smoking prevention programmes are widely offered, it was important to update the Cochrane review, first undertaken in 2002, and thereby establish the current effectiveness of school-based interventions.1

STUDY CHARACTERISTICS

Any type of school-based intervention programme that aimed to prevent smoking use with any sort of comparison was included in the review. The primary outcome measure was changed from baseline measurement in reported tobacco use, with at least 6 months follow-up postintervention. Participants were either children (5-12 years) and/or adolescents (13-18 years) during the time of the intervention. The review included any type of research design in which students, classes, school, or districts were randomized to either an intervention programme or a control group. The search identified 134 studies (133 cluster randomized controlled trials, one randomized controlled trial) with a total of 428 293 participants from 25 countries. Approximately half of the reviewed studies were deemed to be 'low risk' and the remainder 'uncertain risk' of selection bias. Blinding was uncertain in the majority of cluster randomized controlled trials. Most studies were 'low or uncertain risk' of attrition bias and 'low risk' of reporting bias. A large number of studies (49) did not provide sufficient data to be analysed in the review; however, the reviewers also deemed that these studies were more likely to be subject to selection bias.

The reviewers presented the reviewed evidence in the form of pure-prevention studies that involved only participants who had 'never smoked' at study baseline, trials that only reported change in smoking behaviour over time, and point prevalence of smoking studies, wherein cross-sectional information from a class or school was gathered about smoking rates before the intervention and at follow-up. Meta-analyses were undertaken wherever possible.

1. Meta-analysis of 'pure-prevention' interventions (49 trials with 142 447 participants found no overall effect of programmes versus control at 1 year or less, following the intervention [odds ratio (OR) 0.94, 95% confidence interval (CI) 0.85-1.05]. Nonetheless, a subgroup analysis identified that six trials with combined social competence and influence curricula did prevent smoking (OR 0.49, 95% CI 0.28-0.87). There was, however, no effect for the one information-only study (OR 0.12, 95% CI 0.00-14.87), 25 social influences studies (OR 1.00, 95% CI 0.88-1.13), or five multimodal studies (OR 0.89, 95% CI 0.73-1.08). No 'social competence-only' programme was included in the review.When all the trial results were pooled at longest-term follow-up, an overall significant effect was found (OR 0.88, 95% CI 0.82-0.96). Subsequent subgroup analysis did not detect differences for information-only, social influence-only and multimodal interventions. Subgroup analysis of adult-led pure-prevention programmes in comparison with those led by peer presenters (analysis based on data from 56 study arms/groups) also had a significant impact (OR 0.88, 95% CI 0.81-0.96) at 13 months or more postintervention. Overall, adding booster sessions did not impact pooled data at 1 year or less (OR 0.94, 95% CI 0.85-10.5; based on 36 arms) or at longest follow-up (OR 0.90, 95% CI 0.83-0.97, P = 0.1; 66 arms).

2. A meta-analysis of trials that reported only a change in smoking behaviour over time (15 trials with 45 555 participants) at '1 year or less' found that fewer controls commenced smoking (standardized mean difference 0.04, 95% CI 0.02-0.06). There was no significant difference at longest-term follow-up (standardized mean difference 0.01, 95% CI -0.00 to 0.02).

3. A meta-analysis could not be performed on studies that reported point prevalence of smoking (25 trials) data because they were too heterogeneous. In 16 trials (21 comparison arms), at '1 year or less', eight of 21 comparisons favoured the control and at longest-term follow-up, 20 of 25 studies favoured the control.

IMPLICATIONS FOR NURSING CARE

Pure-prevention interventions (with nonsmoking participants at the start of the study) lowered smoking commencement rates in the year following the intervention (longest follow-up). Trials that combined social competence building and influence-resisting pure-prevention interventions, however, had an effect both in the '12 months following' and 'at 13 months and longer' postintervention time periods. For interventions with follow-up longer than 1 year, adult-led interventions were more effective than peer-led ones.

IMPLICATIONS FOR RESEARCH

Further research is needed with standardized outcomes, clearly defined and analysed smoking career stage of participants (i.e. never-smoker, experimenters, etc.), that compare sex and ethnic group differences. Studies should follow-up participants for more than 1 year, undertake economic evaluations and explore further the effectiveness of social competence alone and combined social competence with influence interventions.

Reference