骨质疏松症以骨矿含量或骨密度进行定义，是一种能准确预测骨折危险的标志。然而，人们对不同社区中骨量及其与骨折危险性关系的流行病学尚不了解。相反，我们却深知国家间髋部骨折的危险性可相差１０倍之多。这种差别的原因还不清楚，但体力活动上的差异似乎是一种可能的假设。由于老龄人口的增长及性别与年龄危险性的增加，髋部骨折的问题很可能与日俱增。 Osteoporosis, defined as bone mineral content or bone density, is a hallmark of accurate prediction of fracture risk. However, the epidemiology of bone mass and the risk of fractures in different communities is unknown. On the contrary, we know that there is a tenfold difference between the risks of hip fracture in different countries. The reason for this difference is unclear, but differences in physical activity seem to be a possible hypothesis. Due to the growth of the aging population and the increased risk of gender and age, hip fracture problems are likely to increase with each passing day.