Family context and the physical activity of adolescents: comparing differences

Family context plays an important role with regard to the physical activity (PA) of adolescents. Intense changes in family composition, including an increase of single-parent structures can affect behavior. To estimate the prevalence of PA, between boys and girls of 11-17 years old, and investigate its association with family context variables. A cross-sectional population-based study "The BH Health Study" was conducted in two health districts of Belo Horizonte. The outcome was PA (≥ 300 minutes/week), which was created from a score that combined time and frequency of cycling and walking to school and leisure time. The independent variables were family context, sociodemographic characteristics and nutritional status. Poisson regression was used with a robust variance and was stratified by gender. 1,015 adolescents participated, 52.8% of whom were male, with a mean age of 14 (± 1.9) years old. The prevalence of PA was 38.8% for girls and 54.5% for boys. Among girls, the family context variables were not significantly associated with PA. Boys were more active when there was an adult in the household reported who did PA (PR = 1.26; 95%CI 1.02 - 1.55) and when living with a single mother (PR = 1.63; 95%CI 1.01 - 2.63). It was also observed that boys that live with their mother and father (PR=1.90; 95%CI 1.06 - 3.41) or only with their mother (PR = 1.82; 95%CI 1.01 - 3.27) reported did PA more frequently in their free time. The presence of an active adult in the household, mainly the mother, appears to be an important factor associated with boys' PA.