The epidemiology and definition of osteoporosis

Osteoporosis is operationally defined in terms of bone mineral mass or apparent density and is an accurate predictor of fracture risk. The clinical significance of osteoporosis lies in the Fractures that arise. Common sites of fracture include the forearm, spine and hip. Of these, the greatest morbidity, mortality and costs ate accounted far by hip fracture. In many countries the size of the problem is increasing due in part to the increasing ge and sex specific incidences. Also, Fracture risk differs markedly between countries and in the case of hip fracture the risk varies by more than IO-fold. The reasons for the differences are not known but differences in physical activity is a plausible hypothesis.