A Component Evaluation of a Randomised Control Community Intervention to Reduce Adolescent Alcohol Use in Australia.

Despite a decline in Australian adolescents reporting to have consumed alcohol, a high proportion of the adolescent population still consumes alcohol. Community-led prevention interventions that systematically and strategically implement evidence-based programs have been shown to be effective in producing population-behaviour change related to youth alcohol and drug use. This study evaluated the post-intervention effects of a multi-component community intervention in Australia. It comprised social marketing targeting adolescents and parents, and a community intervention to reduce underage alcohol sales. Structural equation modelling was used to examine direct and indirect effects of community intervention components on intention and consumption. Self-report surveys (N = 3377) and community sales data (27 communities) were analysed to evaluate the effect of the intervention components on intention and consumption before the age of 18. The intervention reduced alcohol sales to minors (OR = .82). Exposure to the social marketing was significantly associated with household no-alcohol rules (OR = 2.24) and parents not supplying alcohol (OR = .72). The intervention predicted intention not to consume alcohol before age 18; intention was associated with not consuming alcohol (OR = 5.70). Total indirect effects from the intervention through to intention were significant. However, parents setting a rule and not supplying alcohol were the only significant direct effects to intention. Parents setting a rule was directly associated with lower consumption. Overall, the intervention logic was supported by the data modelling. The study extends prior knowledge of community-based interventions to prevent adolescent alcohol use by identifying critical intervention components and effect mechanisms. ClinicalTrials.gov Identifier: ACTRN12612000384853.