Prevalence of adolescent risk behaviors at 11 and 15 years of age: data from the 2004 Pelotas birth cohort.

OBJECTIVES: The objective of this study was to investigate the prevalence of the following risk behaviors: experimentation with cigarettes, electronic cigarettes, alcohol, substances, delinquent behavior, and sex at age 15, stratified by sex and socioeconomic position. We also investigated the prevalence of cigarette and alcohol experimentation at age 11 and the persistence and cumulative incidence of these behaviors between 11 and 15 years of age. METHODS: 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. CONCLUSION: Further research should clarify causal paths of the high prevalence of risk behaviors during adolescence and its increase among girls.