BACKGROUND AND AIMS: Role models around the adolescent, including parents, peers, best friends, and older siblings all act in ways to socialize the adolescent into alcohol use. This study aims to examine the effect of exposure to sibling's drinking alongside the more traditionally examined role models on alcohol use among adolescents.

DESIGN AND SETTING: A longitudinal study followed adolescents from the Netherlands (45.6% male) who completed a questionnaire every six months over three years (seven in total). This resulted in 5,112 observations clustered in 765 participants between 10 and 16 years old.

MEASUREMENTS: We examined three alcohol use measures: alcohol use in the last 6 months, in the last 4 weeks and binge drinking in the last 4 weeks - both cross-sectionally at each timepoint and their change from one timepoint to the next in a series of multilevel logistic regression models.

FINDINGS: Results revealed a non-significant difference in any of the exposure or alcohol use variables between those with or without older siblings. Higher exposure to sibling drinking was significantly associated with all alcohol use outcomes: use in the last 6 months; and binge drinking. When adding the other role models (i.e., peers, mothers, fathers and best friends), the significant association between sibling's exposure and adolescent's alcohol use remains.

CONCLUSION: It would appear that, after adjustment for the effect of role models, adolescents who are exposed to more sibling drinking are more likely to have drunk alcohol in the past 6 months and past 4 weeks, and also to binge drink.