Prevalence of osteoporosis in women referred for bone density testing: utility of multiple skeletal sites

The objective of this study was to determine retrospectively the prevalence of osteoporosis in a referral population and to compare the effectiveness of measuring multiple skeletal sites for identifying osteoporosis. Although osteoporosis is considered to be a major public health problem in the United States, and there are reliable methods for diagnosis based on bone densitometry, fewer than 25% of cases are currently identified. There is no consensus about which skeletal site(s) should be measured for optimal results. In this study, bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) at the radius (proximal site), lumbar spine, femoral neck, and total proximal femur regions in 537 consecutive white females age 50 and older referred by community physicians for bone densitometry. The prevalence of osteopenia and osteoporosis (based on the World Health Organization definitions) was determined, as well as the incidence of misclassification of patients based on different skeletal sites. Overall, 53.3% had osteoporosis, an additional 37.7% had osteopenia, and only 8.7% had normal BMD at all measurement sites. The prevalence was similar at all measurement sites and the incidence of misclassification was low. Given the magnitude of undetected osteoporosis and the efficacy of bone densitometry at any skeletal site, these data have important implications for the optimal deployment of bone density measurement facilities.