Bone mass, skin color and body size among black and white women.

We investigated the relationship between bone mass and two variables, skin color and body size, that may contribute to the higher prevalence of osteoporosis among white than among black populations. From a sample of 36 black and 99 white women were obtained measurements of height, weight, skin color (Photovolt 670 reflectometer) and radial bone mineral content (BMC) and bone width (BW) (single photon absorptiometry). There was no significant correlation between skin reflectance and age-adjusted BMC in either population. Multiple regression models of BMC and BMC/BW on age, weight/height and skin reflectance yielded significant correlations ranging from 0.62 to 0.77, but the partial coefficients for skin reflectance were not significant. BMC and age were negatively correlated in both groups, with a significantly steeper slope for the whites. Weight was positively correlated with BMC in both populations, but differences in weight did not explain the differences in bone mass between the blacks and whites.