Association between low bone density and stroke in elderly women: The study of osteoporotic fractures

Background and Purpose: To determine whether women with low bone mineral density are at increased risk of stroke, the present study was conducted. Methods: We studied 4024 ambulatory women aged 65 years or older participating in the prospective Study of Osteoporotic Fractures. Bone mineral density was measured at baseline using single photon absorptiometry; strokes were ascertained using a computerized Medicare data base and death certificates. Results: During a mean of 1.98 years of follow-up, 83 women suffered first strokes (five fatal). Osteopenia was associated with an increased stroke risk Each SD decrease in bone mineral density at the calcaneus (0.09 g/cm2) was associated with a 1.31-fold increase in stroke (95% confidence interval, 1.03-1.65), adjusted for age, follow-up time, and several potential confounders, including diabetes, systolic blood pressure, use of alcohol, cigarettes or postmenopausal estrogens, cognitive ability, grip strength, and functional ability. The observed relation between bone density and stroke was strongest for intracerebral hemorrhages and occlusions. Conclusions: Most likely, low bone density does not cause stroke; some other process probably results in both osteopenia and cerebrovascular disease.