Ethnic differences in composite indices of femoral neck strength
- 208 Downloads
Bone mineral density does not explain race/ethnicity differences in hip fracture risk. In this study, we demonstrated that race/ethnicity differences in composite hip strength indices were consistent with documented race/ethnicity differences in hip fracture risk, suggesting that unlike bone density, the composite indices may represent ethnicity-independent measures of bone strength.
African–American and Asian women have lower risks of hip fracture than Caucasian women, but such racial/ethnic variation in hip fracture risk cannot be explained by bone mineral density (BMD). The composite indices of femoral neck strength integrate femoral neck and body size with BMD and predict hip fracture risk in Caucasian women. We hypothesize that unlike race/ethnic differences in BMD, race/ethnic differences in the composite strength indices would be consistent with race/ethnic differences in hip fracture risk.
We studied a community-based sample of Caucasian (n = 968), African–American (n = 512), Chinese (n = 221), and Japanese (n = 239) women, premenopausal or in early perimenopause, from the Study of Women's Health Across the Nation.
Unadjusted indices were similar in Caucasian and African–American women but higher in Asian women. After adjusting for age, body mass index, and menopause status, all three minority groups had higher composite strength indices than Caucasian women. Foreign-born Japanese women had higher unadjusted and adjusted composite strength indices than US-born Japanese women, but such differences by nativity were not observed in Chinese women.
We concluded that composite strength indices have the potential to explain racial/ethnic differences in hip fracture risk, suggesting that composite strength indices may represent ethnicity-independent measures of bone strength. This contention needs to be verified by further research on the fracture predictive ability of composite strength indices in multi-ethnic longitudinal cohorts.
KeywordsBone size Composite strength indices Ethnic difference Femoral neck strength Hip geometry Nativity
- 3.Siris ES, Miller PD, Barrett-Connor E, Faulkner KG, Wehren LE, Abbott TA, Berger ML, Santora AC, Sherwood LM (2001) Identification and fracture outcomes of undiagnosed low bone mineral density in postmenopausal women: results from the National Osteoporosis Risk Assessment. Jama 286(22):2815–2822CrossRefPubMedGoogle Scholar
- 9.Johnell O, Kanis JA, Oden A, Johansson H, De Laet C, Delmas P, Eisman JA, Fujiwara S, Kroger H, Mellstrom D, Meunier PJ, Melton LJ 3rd, O'Neill T, Pols H, Reeve J, Silman A, Tenenhouse A (2005) Predictive value of BMD for hip and other fractures. J Bone Miner Res 20(7):1185–1194CrossRefPubMedGoogle Scholar
- 10.Kanis JA, Oden A, Johnell O, Johansson H, De Laet C, Brown J, Burckhardt P, Cooper C, Christiansen C, Cummings S, Eisman JA, Fujiwara S, Gluer C, Goltzman D, Hans D, Krieg MA, La Croix A, McCloskey E, Mellstrom D, Melton LJ 3rd, Pols H, Reeve J, Sanders K, Schott AM, Silman A, Torgerson D, van Staa T, Watts NB, Yoshimura N (2007) The use of clinical risk factors enhances the performance of BMD in the prediction of hip and osteoporotic fractures in men and women. Osteoporos Int 18(8):1033–1046CrossRefPubMedGoogle Scholar
- 16.Mackey DC, Eby JG, Harris F, Taaffe DR, Cauley JA, Tylavsky FA, Harris TB, Lang TF, Cummings SR (2007) Prediction of clinical non-spine fractures in older black and white men and women with volumetric BMD of the spine and areal BMD of the hip: the Health, Aging, and Body Composition Study*. J Bone Miner Res 22(12):1862–1868CrossRefPubMedGoogle Scholar
- 34.Sowers M, Crawford S, Sternfeld B, Morganstein D, Gold E, Greendale G, Evans D, Neer R, Matthews K, Sherman S, Lo A, Weiss G, Kelsey J (2000) Design, survey, sampling and recruitment methods of SWAN: a multi-center, multi-ethnic, community based cohort study of women and the menopausal transition. Menopause: biology and pathobiology. Academic, San DiegoGoogle Scholar