DIFFERENTIAL EFFECT OF RACE ON THE AXIAL AND APPENDICULAR SKELETONS OF CHILDREN

The prevalence of osteoporosis and the incidence of fractures are subs tantially lower in black than in white subjects, a finding generally a ttributed to racial differences in adult bone mass. Whether these raci al differences are present in childhood is the subject of considerable interest, as the amount of bone gained during growth is a major deter minant of future susceptibility to fractures. We measured the density and size of the vertebrae and femurs of 80 black and 80 white healthy children, 8-18 yr of age, matched for age, gender, height, weight, and stage of sexual development, using computed tomography. Race had a si gnificant and differential effect on the bones in the axial and append icular skeletons. In the axial skeleton, black children had greater ca ncellous bone density, but similar cross-sectional area of the vertebr al bodies. In contrast, in the appendicular skeleton, black children h ad greater femoral cross-sectional area, but similar cortical bone are a and cortical bone density. Compared to white children, vertebral bon e density and femoral cross-sectional area at sexual maturity were, on the average, 10.75% and 5.7% higher, respectively, in black children. Such significant variations may contribute to the racial differences in the prevalence of osteoporosis between black and white adults.