Osteoporosis Ask The Expert
April 14, 2007
Answer from Dr. Gruber The answer to your question is not entirely known, although certain factors probably contribute. First however, it is important to recognize that the data indicate that among Asians the rate of hip fractures varies considerably whether one is speaking of Japanese, American-Asians, Koreans, New Zealand, Hawaii, etc. In general, Asian women have higher fracture rates than African-Americans but lower than Caucasians. Presumably racial and ethnic influences on risk for developing osteoporosis and fragility fractures depends on (undefined) genetic factors which govern bone mass, geometry, and size of bones (all contributing to strength), bone turnover rates, overall body composition (both muscle mass and fat lessen fracture rates), and calcium metabolism. In addition, lifestyle issues such as physical activity, smoking, etc. probably play a role although this has not been well studied in terms of its relationship to race and ethnicity. In summary, a wide range in fracture incidence worldwide suggests that many factors enter into the determination of skeletal health. Bone mass itself (i.e., bone density) is only a portion of the risk profile.