In this cohort study, we included 3,491 11-year-olds and 1,949 15-year-olds from the 2004 Pelotas Birth Cohort. All outcomes were identified via confidential questionnaires and were analyzed as binary variables.
Results:
At age 11, there was a higher prevalence of cigarette experimentation among boys. At age 15, there was a higher prevalence of experimentation with alcohol, cigarettes, and substances among girls; experimentation with cigarettes and sex were more prevalent among those in a low socioeconomic position. We found a high cumulative incidence of alcohol experimentation, as well as persistent alcohol experimentation, in both boys and girls.