Overweight and obesity in Brazilian adolescents

OBJECTIVE: This study aimed to describe the prevalence of overweight and ob esity (OW+O) among Brazilian adolescents and to identify risks for subpopul ations defined according to the five country macro-regions and situation (u rban-rural) of the domiciles, income, years of school attendance, age and s ex. DESIGN: A nationwide home-based survey representative of the Brazilian civi lian noninstitutionalized population, performed in 1989. METHODS: The sampling plans followed a stratified, multistage, probability cluster design in The National Research of Health and Nutrition sample, whi ch collected anthropometric data of 14,455 domiciles. In all, 13,715 adoles cents ranging from 10 to 19 y of age were studied. The OW + O was defined f rom a body mass index (BMI) equal or superior to the 85th percentile of the reference population of the NCHS. The prevalences in the different studied groups were compared using the adjusted odds ratio in logistic regression models. RESULTS: The prevalence of OW + O was of 7.7%, reaching 10.6% within the fe male group and 4.8% within the male group. A direct relation could be estab lished between the socioeconomic level and OW + O. Adolescents of the most industrialized region of the country presented a risk of OW + O 1.86 (95% C l 1.51 - 2.30) times higher than that found in the least developed region. Male youngsters who lived in urban areas were more liable (OR = 1.71, 95% C l 1.30-2.25) to overweight than their counterparts of rural areas. The occu rrence of menarche increased two and a half times (OR = 2.58, 95% CI 2.11 - 3.15) the risk of OW + O within the female group of adolescents. CONCLUSIONS: The results demonstrate a low prevalence of OW + O among Brazi lian adolescents when compared with adolescents of more industrialized regi ons. The OW + O is twice as high within the female group, which represents a much greater difference than the one encountered in industrialized countr ies, probably owing to the muscular work carried out preponderantly by male adolescents of lower socioeconomic levels. Higher prevalences in subpopula tions of higher socioeconomic level and of more industrialized regions show the great need for differentiated actions to control overweight and obesit y in the country.