[Social mobility, lifestyle and body mass index in adolescents].

OBJECTIVE To analyze the association between social mobility, lifestyle and body mass index in adolescents. METHODS A cohort study of 1,716 adolescents aged 10 to 17 years of both sexes. The adolescents were participants in a cohort study and were born between 1994 and 1999. The adolescents, from public and private schools, were assessed between 2009 and 2011. Lifestyle was assessed by interview and anthropometry was used to calculatebody mass index. For the economic classification, both at pre-school age and in adolescence, the criteria recommended by the Brazilian Association of Research Companies were used. Upward social mobility was categorized as an increase by at least one class in economic status within a 10-year-period. Poisson regression was used to estimate the association between upward social mobility and the outcomes assessed. RESULTS Among all respondents (71.4% follow-up of the cohort), 60.6% had upward social mobility. Among these, 93.6% belonged to socioeconomic class D and 99.9% to economy class E. Higher prevalence of social mobility was observed for students with black skin (71.4%) and mulatto students (61.9%) enrolled in public schools (64.3%) whose mothers had less schooling in the first evaluation (67.2%) and revaluation (68.7%). After adjustment for confounding variables, upward social mobility was associated only with sedentary behavior (p = 0.02). The socioeconomic class in childhood was more associated with the outcomes assessed than was upward mobility. CONCLUSIONS Upward social mobility was not associated with most of the outcomes evaluated, possibly as it is discreet and because the period considered in the study may not have been sufficient to reflect substantial changes in lifestyle and body mass index in adolescents.