Evolution of total body and regional adiposity from late adolescence to early adulthood in a birth cohort study

BACKGROUND: Differences in total body and regional adiposity according to sex are observed from an early age, but these differences become more evident after puberty due to hormonal changes. We aimed to assess the evolution of total body and regional adiposity from 18 to 22 years of age and the associated sociodemographic and nutritional characteristics. METHODS: In total, 3274 individuals from the 1993 Pelotas birth cohort study followed up at 18 and 22 years of age. Measures of total body and regional adiposity were assessed using whole-body dual-energy X-ray absorptiometry (DXA) and the TC2 Three-Dimensional Photonic Scanner. We used fat mass index obtained from DXA as a measure of total body adiposity, and android and gynoid fat mass percentages (android or gynoid fat mass [kg]/total fat mass [kg])*100) as measures of regional adiposity. In addition, waist, hip and thigh circumferences from the photonic scanner were also used as measures of regional adiposity. We evaluated these measurements at 18 and 22 years of age by sex and estimated differences between them according to sociodemographic and nutritional characteristics. RESULTS: While men and women did not differ in terms of BMI, females exhibited a higher fat mass index, gynoid fat mass percentage, and hip and thigh circumferences; men exhibited higher android fat mass percentage and waist circumference at both time points. Increases in all body measurements from age 18 to 22 were observed in men and women, except for gynoid fat mass percentage, which decreased in both sexes. Socioeconomic position and race were the independent variables most associated with adiposity rising from age 18 to 22 in women, with black women and women of lower socioeconomic positions exhibiting larger increases in adiposity. CONCLUSION: There was an increase in adiposity and a centralization of body shape from late adolescence to early adulthood, indicating possible early risks for noncommunicable diseases in this cohort.