To test the hypothesis that first alcohol use during childhood is associated with heavy drinking patterns during adolescence and with parental drinking patterns and parental rules about alcohol consumption.

A national cross-sectional survey of 17 371 high-school students. Students were drawn from 789 public and private schools in all the Brazilian state capitals using a multistage probabilistic sampling method and a self-report questionnaire. Weighted data were analyzed through logistic regression testing for differences on the associated factors for first use of alcohol during childhood. Survival analysis and Cox proportional hazard models were used to confirm results.

Among the 82% alcohol lifetime users, 11% had first used alcohol before age 12 years. The lack of perception of possible punishment by parents is associated with childhood alcohol use (OR 2.22, 95% CI 1.67-2.95). Adolescents who first used alcohol during childhood compared with those who only used alcohol at later ages are more likely to engage in binge drinking behaviors (OR 1.57, 95% CI 1.17-2.10), to have a pattern of heavy alcohol use (OR 1.98, 95% CI 1.26-3.09), and to have recently used illegal drugs (OR 1.74, 95% CI 1.39-2.16). According to hazard ratios, students with an earlier age of onset were more likely to have used tobacco and any illegal drug in the past year.

Childhood alcohol may be a risk factor for the most dangerous patterns of alcohol use in adolescence and is associated with parental alcohol use. Parental rules about child alcohol use must be clear because perception of punishment might delay the age of first alcohol use.