Mudança da atividade física na adolescência e seus preditores: um estudo prospectivo no Sul do Brasil

Abstract

OBJECTIVES: The aim of this study was to evaluate the prevalence of physical activity and its correlates among adolescents aged 14-15 years. METHODS: A cross-sectional study was carried out in Pelotas, Southern Brazil, comprising 4325 individuals from the 1993 Birth Cohort. Physical activity was analyzed using three approaches: 1) prevalence of any leisure-time physical activity; 2) prevalence of any active commuting to school; 3) prevalence of engagement in at least 300 min/wk of a combination of both. The correlates examined included demographic, socioeconomic, behavioral, social and biological factors, as well as the number of leisure-time physical activities practiced. Statistical analyses were done through Poisson regression. RESULTS: The proportion of adolescents engaged in any leisure-time physical activity was 75.6%; and 73.4% were active commuters. Total physical activity prevalence (score  300 min/wk) was 48.2%, being higher for boys (62.6%) than girls (34.5%), and increasing linearly according to the number of physical activities performed (p<0.001). The correlates of physical activity according to the 300 min/wk threshold were: being non-white, having failed at school and time spent playing video games. Lower socioeconomic status, higher computer use and parents physical activity demonstrated association only among girls only. CONCLUSIONS: Fewer than half of adolescents met the recommendations for physical activity, and this proportion tended to decrease among the wealthiest. Correlates of physical activity in adolescence differed according to the domain investigated (i.e. leisure time or transport). Engagement in a wide variety of physical activities should be encouraged since childhood.