Publication Highlights

Background and Aims: Recent research suggests parental supply of alcohol is associated with more risky drinking and alcohol‐related harm among adolescents. However, the overall effect of parental supply across adolescence remains unclear because parental supply of alcohol varies over adolescence. Due to the complexity of longitudinal data, standard analytic methods can be biased. This study examined the effect of parental supply of alcohol on alcohol‐related outcomes in early adulthood using robust methods to minimise risk of bias.

Participants: Cohort of school students (n=1906) recruited in the first year of secondary school (average age 12.9yrs) from Australian schools in 2010‐11, interviewed annually for seven years.

Measurements: The exposure variable was self‐reported parental supply of alcohol (including sips/whole drinks) across five years of adolescence (waves 1‐5). Outcome variables were self‐reported binge drinking, alcohol‐related harm, and symptoms of alcohol use disorder, measured in the two waves after the exposure period (waves 6‐7). To reduce risk of bias, we used Targeted Maximum Likelihood Estimation to assess the (counterfactual) effect of parental supply of alcohol in all five waves versus no supply, on alcohol‐related outcomes.

Findings: Parental supply of alcohol across adolescence saw greater risk of binge drinking (RR:1.53; 95% CI:1.27‐1.84) and alcohol‐related harms (RR:1.44; 95% CI:1.22‐1.69) in the year following the exposure period compared with no supply in adolescence. Earlier initiation of parental supply also increased risk of binge drinking (RR:1.10; 95% CI:1.05‐1.14), and any alcohol‐related harm (RR:1.09; 95% CI:1.05‐1.13) for each year earlier parental supply began compared with later (or no) initiation.