Association between binge drinking, type of friends and gender: a cross-sectional study among Brazilian adolescents.

Background: Hazardous drinking among adolescents is a major public health concern. The purpose of this study was to examine the prevalence of binge drinking/alcohol consumption and its association with different types of friendship networks, gender and socioeconomic status among students in Belo Horizonte, Minas Gerais, Brazil.

Methods: We conducted a cross-sectional study on a representative random sample of 891 adolescents (41% male, aged 15-19 years) from public and private schools in 2009-2010. Information on friendship networks and binge drinking was collected using two validated self-administered questionnaires: the Integrated Questionnaire for the Measurement of Social Capital and the first 3 items in the Alcohol Use Disorders Identification Test (AUDIT C). We used the area-based Social Vulnerability Index (SVI), mother and father's educational background, and the type of school to assess socioeconomic status. The chi-squared test was used to examine the associations between sample characteristics or the type of friends and binge drinking (p-values <0.05 were considered statistically significant). Ordinal logistic regression was used to estimate the association between binge drinking and the independent variables.

Results: A total of 321 (36%) adolescents reported binge drinking (5 or more drinks in one occasion), and among them, 233 (26.2%) adolescents reported binge drinking less than monthly to monthly, and 88 (9.9%) weekly to daily. Binge drinking was associated with being male (OR = 1.52, 95% CI 1.01-2.28) and with living in a low vulnerability area (having the best housing conditions, schooling, income, jobs, legal assistance and health) (OR = 1.66, 95% CI 1.05-2.62). Students who reported that their closest friends were from school (as opposed to friends from church) had an increased risk of binge drinking (OR = 3.55, 95% CI 1.91-5.87). In analyses stratified by gender, the association was significant only among the female students.

Conclusions: The prevalence of binge drinking was high in this sample of Brazilian adolescents, and gender, low social vulnerability and friendship network were associated with binge drinking.