Hip fracture incidence rates are predicted to increase dramatically in the first half of the 21st century, especially in Asia, Latin America, Africa, and the Middle East. These increased rates will result primarily from the effects of public health efforts to improve nutrition and infectious-disease control, both of which contribute to improved longevity of populations. An example of a rapid increase in hip fracture incidence rates has been reported in Hong Kong. Findings of studies there suggest that environmental changes, ie, westernization, urbanization, or both, are strongly related with declines in bone mineral density and increases in fractures. Hip fracture incidence rates in Western nations are typically increasing at much more modest rates than those in Hong Kong and other Asian nations. Epidemiologic investigations have identified multiple risk factors, including exposures earlier in life to adverse factors that are considered to contribute to the development of osteoporosis in both Western and Asian nations. The major risk factors are inadequate nutrition, limited physical activity, and low lifetime estrogen exposure. A dietary shift toward a more plant-based diet in Western nations may be beneficial to bone health, but is not likely to counter the adverse effects of limited physical activity and low estrogen exposure.