Tobacco use and friendship networks: a cross-sectional study among Brazilian adolescents.

AIM: To determine the prevalence of tobacco use and its association with types of friendship networks, socioeconomic status and gender among Brazilian adolescents. METHODS: A cross-sectional study was carried out with a representative sample of 905 students aged 15 to 19 years. Information on social networks and tobacco use was collected by the self-administered questionnaire 'Alcohol, Smoking and Substance Involvement Screening Test" and the question "What is your most important group of close friends?'. Socioeconomic status was assessed using an area-based social vulnerability index and type of school. Multinomial logistic regression analysis was employed to test associations between tobacco use and the independent variables. RESULTS: The overall prevalence of tobacco use was 18.9%. Female adolescents had 3.80-fold greater odds of reporting weekly to daily tobacco use compared to male adolescents. Participants who reported that their most important groups of close friends were from church had a lower risk of reporting weekly to daily tobacco use in comparison to those who reported that their best friends were from school. CONCLUSIONS: The prevalence of tobacco use was high and was associated with school-based (as compared to church-based) friendship networks, female gender and higher area-level socioeconomic status.