[Nutritional evaluation follow-up of the 1982 birth cohort, Pelotas, Southern Brazil].

OBJECTIVE To estimate the prevalence of over/underweight and its association with demographic and socioeconomic factors. METHODS Longitudinal cohort study of youths born in 1982 in Pelotas, Southern Brazil. In 2004-5 we interviewed 4,198 of the 5,914 cohort subjects, obtaining weight and stature measurements that were used to calculate body mass index (BMI). Underweight was defined as BMI lower than 18,5 kg/m(2); overweight as BMI between 25 and 30kg/m(2); and obesity as BMI IMC > 30kg/m(2). The effects of socioeconomic (family income and schooling) and demographic (skin color) variables, birthweight, and breastfeeding on underweight, overweight, and obesity were analyzed separately for men and women using Poisson regression. RESULTS Prevalence of underweight, obesity, and overweight were 6.0%, 8.2%, and 28.9%, respectively. In adjusted analysis, only birthweight remained associated with underweight among men and women. Poor men showed higher risk of underweight, but were protected from obesity and overweight. By contrast, risk of obesity and overweight was higher among poor women. CONCLUSIONS The present results underscore the importance of socioeconomic determinants on nutritional status, with special emphasis on the distinct effects these factors have among men and women in different nutritional conditions.