Vertebral fractures and mortality in older women - A prospective study

Background: Osteoporotic fractures, including clinically detected vertebral fractures, are associated with increased mortality. However, only one thir d of vertebral fractures are diagnosed. It is unknown whether vertebral fra ctures, whether clinically apparent or not, are associated with greater mor tality. Objectives: To test the hypothesis that women with prevalent vertebral frac tures have greater mortality than those without fractures and to describe c auses of death associated with vertebral fractures. Design: Prospective cohort study with mean follow-up of 8.3 years. Setting: Four clinical centers in the United States. Participants: A total of 9575 women aged 65 years or older and enrolled in the Study of Osteoporotic Fractures. Measurements: Vertebral fractures by radiographic morphometry; calcaneal bo ne mineral density; demographic, medical history, and lifestyle variables; blood pressure; and anthropometric measures. In a subset of 606 participant s, thoracic curvature was measured during a second clinic visit. Main Outcome Measures: Hazard ratios for mortality and cause-specific morta lity. Results: At baseline, 1915 women (20.0%) were diagnosed as having vertebral fractures. Compared with women who did not have a vertebral fracture, wome n with 1 or more fractures had a 1.23-fold greater age-adjusted mortality r ate (95% confidence interval, 1.10-1.37). Mortality rose with greater numbe rs of vertebral fractures, from 19 per 1000 woman-years in women with no fr actures to 44 per 1000 woman-years in those with 5 or more fractures (P for trend, <.001). In particular, vertebral fractures were related to the risk of subsequent cancer (hazard ratio, 1.4; 95% confidence interval, 1.1-1.7) and pulmonary death (hazard ratio, 2.1; 95% confidence interval, 1.4-3.0). In the subset of women who underwent thoracic curvature measurements, seve re kyphosis was also related to pulmonary deaths (hazard ratio, 2.6; 95% co nfidence interval, 1.3-5.1). Conclusion: Women with radiographic evidence of vertebral fractures have an increased mortality rate, particularly from pulmonary disease and cancer.