Purpose: The age of drinking onset is a central concept for both policy and prevention of alcohol-related harm, yet evidence on the predictive value of the age of onset is lacking. This study compares alcohol outcomes of adolescents who started to drink early with those who started later, and tests if associations are moderated by other explanatory factors.

Methods: Data from a two-wave longitudinal prospective cohort survey with a Swedish nationwide sample of 4,018 adolescents aged 15/16 years at baseline (T1) and 17/18 years at follow-up (T2) were used. Outcome variables at T2 were Alcohol Use Disorders Identification Test (AUDIT)–C, risky drinking, and binge drinking monthly or more often. A vast number of explanatory factors at T1 were controlled for.

Results: Early drinking onset predicted later higher AUDIT-C scores (β = 0.57, p value < .001), and higher probability of risky drinking (odds ratio = 1.95, 95% confidence interval = 1.56–2.44), and binge drinking (odds ratio = 1.38, confidence interval = 1.06–1.81), controlled for other explanatory factors. If binge drinking frequency at T1 was included, the associations remained for AUDIT-C and risky drinking, but not for binge drinking at T2. No significant interactions between early drinking onset and the explanatory factors were found.

Discussion: Early drinking onset predicts subsequent higher alcohol consumption in late adolescence. Adolescents who had an early drinking onset drank more after 2 years than their peers who started later. The age of drinking onset is an independent predictor of alcohol use outcomes, beyond the effect of age of binge drinking onset.