The relation of low levels of bone mineral density with coronary artery calcium and mortality.

ABSTRACT

Osteoporosis and atherosclerosis are two prevalent major healthcare concerns that frequently coexist. The clinical outcome of 5590 consecutive subjects who underwent coronary artery calcium (CAC) scanning and thoracic bone mineral density (BMD) measurement was assessed. A significant link between low BMD levels and CAC with increased risk of mortality in both genders across ethnicities noted. INTRODUCTION: While a relation of CAC with lower levels of BMD reported previously; it is unclear whether low levels of BMD would be an independent risk factor for CAC and mortality. This study investigated the relation of BMD levels with CAC and mortality in both genders across ethnicities. METHODS: This study consisted of 5590 consecutive at-risk subjects without known coronary artery disease (CAD), age 57 ± 12, and 69% male, who underwent non-enhanced cardiac computed tomography, and were followed for mean of 8 years. The subjects' CAC (Agatston score) and thoracic BMD levels (mg/cm3) were measured. CAC stratified based on the severity to CAC 0, 1-100, 101-400, and 400+. Low-BMD levels defined as BMD levels below median (180 mg/cm3). Physician verified that all-cause mortality was assessment hard-endpoint. Multivariate regression analysis, adjusted for age, gender, and other cardiovascular risk factors, was used to assess the relationship between BMD and CAC. RESULTS: The BMD levels were proportionally lowering with the severity of CAC in both genders, especially in postmenopausal women (p < 0.05). The risk of each standard deviation reduce in BMD levels increased with the severity of CAC, as compared to CAC = 0 across ethnicities (p < 0.05). Low BMD levels were an independent predictor of mortality and event-free survival rate decreased from 99% in those within normal BMD levels to 93% in those with low BMD levels (p = 0.0001). Furthermore, a significant link between low BMD levels and CAC > 0 with increased risk of mortality was noted (p = 0.0001). The relative risk of death was 2.8, 5.9, and 14.3-folds higher in CAC 1-100, 101-400, and 400+ with low BMD levels, compared to CAC = 0 and within normal BMD levels, respectively (p < 0.05). CONCLUSIONS: The lower BMD levels are independently associated with the severity of CAC that predicts mortality.