Racial difference in the correlates of bone mineral content/density and age at peak among reproductive-aged women

Summary  Racial/ethnic differences were observed in age at peak bone density and their correlates, with whites peaking at least 5 years earlier at the femoral neck than black and Hispanic women. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women. Introduction  The influence of race/ethnicity on bone measurements has not been widely examined. This study identifies age and amount of bone accumulated at peak density and their correlates by race/ethnicity. Methods  Bone mineral content (BMC) and bone mineral density (BMD) of the spine and femoral neck were measured by dual X-ray absorptiometry in 708 white, black, and Hispanic reproductive-aged women. Race-specific nonlinear models were used to describe the relationship between age and bone measurements, after adjusting for body weight and height. Log-transformed bone measurements were used to determine predictors based on multiple linear regression. Results  Predictors, which were race and site specific, included age, age at menarche, body weight, height, months of depot medroxyprogesterone acetate use, weight-bearing exercise, and alcohol use. Women of all races gained BMC and BMD at the spine up to 30–33 years of age. BMC and BMD of the femoral neck peaked among white women earlier (≤16 years) than among blacks (BMC 22 years; BMD 21 years) and Hispanics (BMC 29 years; BMD 20 years). Conclusion  Age at peak bone mass and its correlates differ by race/ethnicity. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women. This work was supported by the National Institute of Child Health and Human Development grants R01HD39883 and K24HD043659 awarded to ABB and General Clinical Research Centers (GCRC) program, National Center for Research Resources, NIH, M01RR000073.