A Cochrane rev iew [Abstract] 1 identified 134 randomized controlled trials involving a total of 428 293 participants. Pure Prevention cohorts (Group 1) included 49 studies (n=142 447). Pooled results at follow-up at one year or less found no overall effect of intervention curricula versus control (odds ratio (OR) 0.94, 95% CI 0.85 to 1.05). In a subgroup analysis, the combined social competence and social influences curricula (6 RCTs) showed a statistically significant effect in preventing the onset of smoking (OR 0.49, 95% CI 0.28 to 0.87; 7 arms); whereas significant effects were not detected in programmes involving information only (OR 0.12, 95% CI 0.00 to 14.87; 1 study), social influences only (OR 1.00, 95% CI 0.88 to 1.13; 25 studies), or multimodal interventions (OR 0.89, 95% CI 0.73 to 1.08; 5 studies). In contrast, pooled results at longest follow-up showed an overall significant effect favouring the intervention (OR 0.88, 95% CI 0.82 to 0.96). This represents a risk reduction of 12%. Subgroup analyses detected significant effects in programmes with social competence curricula (OR 0.52, 95% CI 0.30 to 0.88), and the combined social competence and social influences curricula (OR 0.50, 95% CI 0.28 to 0.87), but not in those programmes with information only, social influence only, and multimodal programmes.
Change in Smoking Behaviour over time (Group 2) included 15 studies (n=45 555). At one year or less there was a small but statistically significant effect favouring controls (standardised mean difference (SMD) 0.04, 95% CI 0.02 to 0.06). For follow-up longer than one year there was a statistically nonsignificant effect (SMD 0.02, 95% CI -0.00 to 0.02).
A systematic review 2 described the effectiveness of parent-focused interventions in reducing or preventing adolescent tobacco, alcohol, and illicit substance use. A total of 42 studies were included. Parenting interventions were effective at preventing and decreasing adolescent tobacco, alcohol, and illicit substance use over the short and long term. The majority of effective interventions required 12 or less contact hours and were implemented through in-person sessions including parents and youth. Few interventions were delivered outside of school or home settings.
Comment: The quality of evidence is downgraded by study quality and inconsistency (heterogeneity).
Primary/Secondary Keywords