The 7-year effectiveness of school-based alcohol use prevention from adolescence to early adulthood: An RCT of universal, selective and combined interventions.

Background: Alcohol use is a leading cause of burden of disease among young people. Prevention strategies can be effective in the short-term, however little is known about their longer-term effectiveness. This study examined the sustainability of universal, selective and combined school-based alcohol use prevention implemented in adolescence (13 years) into adulthood (20 years).

Methods: Participants from a cluster randomized controlled trial conducted between 2012-2015 were followed up to 7-years post-baseline. At baseline, participants were 2,190 students (mean age: 13.3 years) from 26 Australian secondary schools. Schools were randomly allocated to one of four intervention conditions: universal prevention for all students (Climate); selective prevention for high-risk students (Preventure); combined universal and selective prevention (Climate and Preventure; CAP); or health education as usual (Control). Primary outcomes were self-reported 1) frequency of alcohol consumption and binge drinking, 2) alcohol-related harms and 3) hazardous alcohol use, at 7-years post-baseline.

Results: Compared to the control group, students in all three intervention groups reported reduced odds of experiencing alcohol-related harms at 7-years post-baseline (ORs=0.13-0.33). In addition, students in the Climate (OR=0.04) and Preventure (OR=0.17) groups reported lower odds of hazardous drinking compared to the control group. The Preventure group also reported lower odds of weekly alcohol use (OR=0.17), and the Climate group reported lower odds of binge-drinking (OR=0.12) compared to the control group. Results from piecewise models suggested slowed growth trajectories of alcohol use during middle adolescence were a key mechanism driving the intervention effects.

Conclusion: This study delineated the long-term sustainability of universal, selective and combined interventions for the prevention of alcohol use. This study demonstrated that both universal and selective preventive interventions delivered in schools can have long lasting effects and reduce risky drinking and related harms into adulthood. No added benefit was observed by delivering the combined interventions.