Factor of risk for hip fracture in normal Chinese men and women in Taiwan

We have investigated the age-related change in Factor of risk (Phi) for the proximal femoral load during free fall in 548 females and 240 males aged 2 1-79 years. These individuals were divided into either young (age <50 years ) or old group (age greater than or equal to 50 years). Another 26 females with hip fractures were included for comparison. The bone mineral density ( BMD) of proximal femoral neck was measured by a Norland XR-26 dual-energy X -ray absorptiometer (DXA). The estimated fracture load (L) of femoral neck was calculated from the BMD with the regression equation derived by Courtne y et al. [2,3] and estimated fall force (F) by body weight and height accor ding to the regression equation derived by Nakamura et al. [6] respectively . Phi was defined as the quotient of F/L. The results showed an age-related decrease of BMD (P < 0.001) in both genders corrected for weight and heigh t. By multiple Linear regression analysis, the F decreased significantly wi th aging corrected for BMD in old males (partial r = -0.255,P < 0.01) and i ncreased with aging in all females (young, partial r=0.287, p < 0.001; old, (partial r = 0.252, P < 0.001). L, decreased significantly with aging corr ected for height and weight in males (young, partial r = -0.401, P < 0.01; old, partials = -0.178, P < 0.05) and females young, partial r = -0.168, P < 0.05; old, partial r = -0.459, P < 0.001). However Phi decreased with agi ng in young males (P < 0.01) and females (young: P < 0.001, old: P < 0.001) . Phi increased in old women but not in old men, and was higher in old wome n compared with old men. The 26 patients with hip fractures had a significa ntly higher Phi value than 85 age-matched women. In conclusion, Phi may pro vide a comprehensive comparison of the risk of hip fracture in the elderly population.