Objective: The aim of this study was to determine the prevalence of overweight in adolescents in a southern Brazilian city, and ascertain gender differences and association with socio-economic and demographic conditions, family factors and individual behaviours.
Methods: Cross-sectional population-based study with random cluster sampling of households, including 722 adolescents (10-19 years), from a city in southern Brazil. Body mass index (BMI) was calculated based on the National Center for Health and Statistics reference curve, defining overweight as BMI 85th percentile.
Results: Prevalence of overweight was 17% in girls and 19% in boys. In multivariate Poisson regression, chronic illness in parent(s) and household of up to four people were associated with overweight in boys, whereas low fibre intake, more hours spent watching television and regular exercise were associated with overweight in girls.
Conclusion: The prevalence of overweight in Brazilian adolescents is high, with gender differences in associated factors. Health workers in schools and public health services should be aware of these differences in order to improve preventive and therapeutic strategies in this age group.