Clinical review: Ethnic differences in bone mass--clinical implications.

CONTEXT

Differences in bone mineral density (BMD) as assessed with dual-energy x-ray absorptiometry are observed between geographic and ethnic groups, with important implications in clinical practice.

EVIDENCE ACQUISITION

PubMed was employed to identify relevant studies. A review of the literature was conducted, and data were summarized and integrated.

EVIDENCE SYNTHESIS

The available data highlight the complex ethnic variations in BMD, which only partially account for observed variations in fracture rates. Factors contributing to ethnic differences include genetics, skeletal size, body size and composition, lifestyle, and social determinants. Despite BMD differences, the gradient of risk for fracture from BMD and other clinical risk factors appears to be similar across ethnic groups. Furthermore, BMD variation is greater within an ethnic population than between ethnic populations. New imaging technologies have identified ethnic differences in bone geometry, volumetric density, microarchitecture, and estimated bone strength that may contribute to a better understanding of ethnic differences in fracture risk.

CONCLUSIONS

Factors associated with ethnicity affect BMD and fracture risk through direct and indirect mechanisms.