Determinants of body composition measured by dual-energy X-ray absorptiometry in Dutch children and adolescents.

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.