Identification and fracture outcomes of undiagnosed low bone mineral density in postmenopausal women - Results from the National Osteoporosis Risk Assessment

Context Large segments of the population at risk for osteoporosis and fract ure have not been evaluated, and the usefulness of peripheral measurements for short-term prediction of fracture risk is uncertain. Objectives To describe the occurrence of low bone mineral density (BMD) in postmenopausal women, its risk factors, and fracture incidence during short -term follow-up. Design The National Osteoporosis Risk Assessment, a longitudinal observatio nal study initiated September 1997 to March 1999, with approximately 12 mon ths of subsequent follow-up. Setting and Participants A total of 200160 ambulatory postmenopausal women aged 50 years or older with no previous osteoporosis diagnosis, derived fro m 4236 primary care practices in 34 states. Main Outcome Measures Baseline BMD T scores, obtained from peripheral bone densitometry performed at the heel, finger, or forearm; risk factors for lo w BMD, derived from questionnaire responses; and clinical fracture rates at 12-month follow-up. Results Using World Health Organization criteria, 39.6% had osteopenia (T s core of -1 to -2.49) and 7.2% had osteoporosis (T score less than or equal to -2.5). Age, personal or family history of fracture, Asian or Hispanic he ritage, smoking, and cortisone use were associated with significantly incre ased likelihood of osteoporosis; higher body mass index, African American h eritage, estrogen or diuretic use, exercise, and alcohol consumption signif icantly decreased the likelihood. Among the 163 979 participants with follo w-up information, osteoporosis was associated with a fracture rate approxim ately 4 times that of normal BMD (rate ratio, 4.03; 95% confidence interval [CII, 3.59-4.53) and osteopenia was associated with a 1.8-fold higher rate (95% Cl, 1.49-2.18). Conclusions Almost half of this population had previously undetected low BM D, including 7% with osteoporosis. Peripheral BMD results were highly predi ctive of fracture risk. Given the economic and social costs of osteoporotic fractures, strategies to identify and manage osteoporosis in the primary c are setting need to be established and implemented.