PHALANGEAL BONE-DENSITY AND HIP FRACTURE RISK

Objective: To assess the long-term predictive usefulness of radiograph ic absorptiometry measurements of phalangeal bone density for hip frac ture risk. Methods: Participants were members of the First National He alth and Nutrition Examination Survey Epidemiologic Follow Up Study co hort. Subjects were followed up for a maximum of 16 years. The First N ational Health and Nutrition Examination Survey data were obtained fro m a nationally representative sample of noninstitutionalized civilians . A cohort of 3481 white and black subjects (1559 white women) aged 45 through 74 years at baseline (1971-1975) were observed through 1987. Ninety-eight percent of the original cohort completed the study. Hospi tal records and death certificates were used to identify a total of 72 hip fracture cases. Phalangeal bone density at baseline was measured using photodensitometry (PD), and later reanalyzed by radiographic abs orptiometry (RA), a newer, more sophisticated technique. Results: Resu lts were evaluated to determine the relative risk for hip fracture per 1-SD decrease in bone density, after controlling for age at baseline, race, gender, weight, and previous fractures. Both RA and PD measurem ents showed a significant inverse relationship to hip fracture risk, w ith RA density measurements showing a slightly higher adjusted relativ e risk per 1-SD density decrease than PD measurements. For RA bone den sity, the relative risk for all subjects was 1.81 (95% confidence inte rval, 1.34-2.44) compared with 1.57 (95% confidence interval, 1.19-2.0 7) for PD bone density after adjusting for age at baseline, race, gend er, weight, and previous fractures. Results for white women were essen tially the same as those for all subjects for RA bone density and PD b one density. Conclusions: Phalangeal bone density determined from stan dard hand x-ray films is a significant predictor of future hip fractur e risk. Availability of a valid method to assess fracture risk using c onventional radiographs will expand the ability to identify individual s with osteoporosis.