Weight gain in childhood and body composition at 18 years of age in Brazilian males

AIM To assess the association between weight gain at different time periods during childhood and measures of adiposity in late adolescence. METHODS A population-based birth cohort carried out in Pelotas, a 320 000-inhabitant city in a relatively developed area in Southern Brazil. All newborns in the city's hospitals were enrolled in 1982. Weight gain from 0-1, 1-2, 2-4 and 4-15 years were expressed as changes in weight-for-age Z-scores relative to the NCHS/WHO reference. In 2000, 79% (2250) of all males were located when enrolling at the national Army. Weight and height were assessed. Body composition indicators (fat mass/height(2), lean mass/height(2), fat mass/lean mass(2.3)) were estimated through bioimpedance. Analyses were adjusted for maternal and social factors, as well as for gestational age. RESULTS In the adjusted analyses, birthweight and weight gain in the first year of life were positively associated with attained height at age 18 years. Except for the fat mass/lean mass(2.3) ratio, all weight-related outcomes were positively associated with weight gain in different periods of life. Children who gained weight rapidly in more than one time period became fatter at age 18 years, independently of when fast growth took place. CONCLUSIONS Height was primarily determined by fetal and infant growth. Weight-related indices, including the fat/lean mass ratio, were more strongly influenced by later growth. No clear critical windows of growth during which absolute tissue masses are programmed could be identified.