MARKERS OF BONE-RESORPTION PREDICT HIP FRACTURE IN ELDERLY WOMEN - THE EPIDOS PROSPECTIVE-STUDY

Increased bone turnover has been suggested as a potential risk factor for osteoporotic fractures, We investigated this hypothesis in a prosp ective cohort study performed on 7598 healthy, women more than 75 year s of age, One hundred and twenty-six women (mean years 82.5) who susta ined a hip fracture during a mean 22-month follow-up were age-matched with three controls who did not fracture, Baseline samples were collec ted prior to fracture for the measurement of two markers of bone forma tion and three urinary markers of bone resorption: type I collagen cro ss-linked N- (NTX) or C-telopeptide (CTX) and free deoxypyridinoline ( free D-Pyr). Elderly women had increased bone formation and resorption compared with healthy premenopausal women, Urinary excretion of CTX a nd free D-Pyr, but not other markers, was higher in patients with hip fracture than in age-matched controls (p = 0.02 and 0.005, respectivel y), CTX and free D-Pyr excretion above the upper limit of the premenop ausal range was associated with an increased hip fracture risk,vith an odds ratio (95% confidence interval) of 2.2 (13-3.6) and 1.9 (1.1-3.2 ), respectively, while markers of formation were not. Increased bone r esorption predicted hip fracture independently of bone mass, i.e., aft er adjustment for femoral neck bone mineral density (BMD) and independ ently of mobility status assessed by the gait speed, Women with both a femoral BMD value of 2.5 SD or more below the mean of young adults an d either high CTX or high free D-Pyr levels were at greater risk of hi p fracture, with an odds ratio of 4.8 and 4.1, respectively, than thos e with only low BMD or high bone resorption, Elderly women are charact erized by increased bone turnover, and some markers of bone resorption predict the subsequent risk of hip fracture independently of hip BMD, Combining the measurement of BMD and bone resorption may be useful to improve the assessment of the risk of hip fracture in elderly women.