Abstract
BACKGROUND: A growing body of evidence links coronary artery atherosclerosis and calcification to osteoporosis in women. The endothelium plays a critical role in maintaining vascular integrity and may play a role in bone metabolism. We aimed to determine whether early coronary atherosclerosis, as detected by coronary microvascular endothelial dysfunction (CMED), predicts the development of osteoporosis in postmenopausal women. METHODS: Coronary vascular reactivity was evaluated in 194 postmenopausal women greater than 50 years of age and with non-obstructive coronary arteries by administration of intracoronary acetylcholine during diagnostic angiography. CMED was defined as ≤50% increase in coronary blood flow from baseline in response to maximal dose. After a median follow-up of 7.0±0.3 years, patients were assessed by a questionnaire for development of osteoporosis. RESULTS: The average age of the cohort was 60.9±7.4 years. Women with CMED were twice as likely to develop osteoporosis compared with women without endothelial dysfunction after adjustment for potential confounders (relative risk, 2.4; 95% confidence interval [CI], 1.1, 5.6, P=0.02). Epicardial endothelial dysfunction was not associated with development of osteoporosis. DISCUSSION: Early coronary atherosclerosis with endothelial dysfunction is an independent marker for increased risk of developing osteoporosis in postmenopausal women greater than 50 years of age without obstructive coronary artery disease. The current study supports a link between coronary atherosclerosis and osteoporosis.