Abstract 11492: Relationship Between Coronary Artery Calcium and Thoracic Spine Bone Mineral Density: The Multi-Ethnic Study of Atherosclerosis

Background: Traditionally, osteoporosis and coronary artery disease were considered unrelated. Beyond age, these two conditions appear to share common etiologies that are not yet fully understood. Objective: We sought to evaluate the relationship between thoracic spine bone mineral density (BMD) and severity of coronary artery calcium (CAC) score. Methods: MESA is a cohort study of 6,814 men and women from six U.S. cities between the ages of 45 and 84 years, who were free of clinical CVD. Included participants had thoracic spine BMD and CAC that was assessed by non-contrast chest CT, using methods previously described by Budoff et al 2010. Multivariate regression analysis was performed to examine the association of thoracic spine BMD and CAC score after adjusting for conventional risk factors of atherosclerosis including age, gender, BMI, race/ethnicity, diabetes, hypertension medications, lipid lowering medications, smoking history and family history of CAD. Results: Correlation coefficient, r, was -0.29 (p<0.0001), indicating inverse relationship between CAC and BMD. BMD was categorized as normal (T-score>-1), osteopenia (-2.5<T-score=<-1) or osteoporosis (T-score<=-2.5). Prevalence of CAC >0 was 36% in normal group, 49% in the osteopenia group and 68% in the osteoporosis group. In adjusted regression models, the odds of CAC were significantly higher in those with osteoporosis (OR: 1.57 95% CI: 1.31,1.88) p<0.0001 and trending higher in those with osteopenia (OR: 1.15; 95% CI:1.00,1.32) p=0.049. Analysis stratified based on gender, the odds of CAC in men with osteoporosis is higher (OR: 1.61; 95% CI: 1.24,2.09) p=0.0004 compared to women with osteoporosis (OR: 1.48; 95% CI: 1.15,1.90) p=0.002. Conclusion: The prevalence of CAC was significantly higher in osteoporosis group compared to normal BMD. There is an inverse relationship between BMD and CAC independent of cardiovascular risk factors.