Hyperkyphosis Predicts Mortality Independent of Vertebral Osteoporosis in Older Women

Background: Excessive kyphosis may be associated with earlier mortality, but previous studies have not controlled for clinically silent vertebral fractures, which are a known mortality risk factor. Objective: To determine whether hyperkyphosis predicts increased mortality independent of vertebral fractures. Design: Prospective cohort study. Setting: Four clinical centers in Baltimore County, Maryland; Portland, Oregon; Minneapolis, Minnesota; and the Monongahela Valley, Pennsylvania. Patients: 610 women, age 67 to 93 years, from a cohort of 9704 women recruited from community-based listings between 1986 and 1988. Measurements: Kyphosis was measured by using a flexicurve. Prevalent radiographic vertebral fractures at baseline were defined by morphometry, and mortality was assessed during an average follow-up of 13.5 years. Results: In age-adjusted models, each SD increase in kyphosis carried a 1.14-fold increased risk for death (95% CI, 1.02 to 1.27; P = 0.023). After adjustment for age and other predictors of mortality, including such osteoporosis-related factors as low bone density, moderate and severe prevalent vertebral fractures, and number of prevalent vertebral fractures, women with greater kyphosis were at increased risk for earlier death (relative hazard per SD increase, 1.15 [CI, 1.01 to 1.30]; P = 0.029). On stratification by prevalent vertebral fracture status, only women with prevalent fractures were at increased mortality risk from hyperkyphosis, independent of age, self-reported health, smoking, spine bone mineral density, number of vertebral fractures, and severe vertebral fractures (relative hazard per SD increase, 1.58 [CI, 1.06 to 2.35]; P = 0.024). Limitation: The study population included only white women. Conclusion: In older women with vertebral fractures, hyperkyphosis predicts an increased risk for death, independent of underlying spinal osteoporosis and the extent and severity of vertebral fractures. Primary Funding Source: National Institute of Arthritis and Musculoskeletal and Skin Diseases and National Institute on Aging.