Body composition and muscle strength as determinants of racial difference in bone mineral density

The purpose of this study was to determine the contribution of body composition and muscle strength to racial differences in bone mineral density (BMD) in chronically active older adults. Participants were 49 men and 56 women grouped according to self-selected race (Black, Asian, or White). BMD, body composition, and knee strength were measured. Asian men had significantly lower body mass, strength, and BMD than White and Black men did (p < .05). Asian and White women had significantly lower body mass and BMD than Black women did (p < .05), with few strength differences between groups. When lean mass was controlled by ANCOVA, racial differences in BMD disappeared for all bone sites in both sexes. Controlling for body mass eliminated most racial differences in BMD. Controlling for strength did not alter racial differences in BMD for either sex. These results suggest that racial differences in BMD might in part result from differences in lean mass.