DIFFERENCES IN BODY-COMPOSITION OF BLACK-AND-WHITE GIRLS

Adults have racial differences in body composition that may modulate r isks resulting from obesity. Although black and white children have be en shown previously to have differences in bone mineral density and su bcutaneous body fat, differences in visceral adipose tissue have not b een evaluated. We studied 20 black and 20 white normal-weight girls ag ed 7-10 y, who were matched for weight, body mass index (BMI), bone ag e, chronological age, Tanner breast stage, and socioeconomic status. E ach underwent anthropometric measurements, bioelectrical impedance ana lysis, dual-energy X-ray absorptiometry (DXA), and abdominal magnetic resonance imaging (MRI) for determination of total (TAT), visceral (VA T), and subcutaneous (SAT) adipose tissue. Serum lipids and fasting an d 2-h oral-glucose-tolerance test (OGTT) glucose and insulin concentra tions were also measured. There were no differences between groups in absolute waist circumference or waist-to-hip ratio, but waist-to-thigh ratio was smaller in black than in white girls. Black girls had great er bone mineral density and less TAT, VAT, and SAT than whites. VAT wa s not significantly correlated with any measure of insulin, or with se rum lipids. However, both basal and 2-h OGTT serum insulin were signif icantly correlated with SAT as assessed by MRI in black girls (r(2) = 0.46 for basal insulin, P = 0.001; r(2) = 0.31 for 2-h insulin, P = 0. 01) but not in white girls (r(2) < 0.05, for basal and 2-h insulin, NS ). We conclude that there are significant racial differences in body c omposition and differences in the strength of association between abdo minal adipose tissue depots and insulin sensitivity in black and white girls.