Association between coronary artery calcium and thoracic spine bone mineral density: Multiethnic Study of Atherosclerosis (MESA).

Background And Aims: Previously, osteoporosis and coronary artery disease were considered unrelated. However, beyond age, these two conditions appear to share common etiologies that are not yet fully understood. We examined the relationship between thoracic spine bone mineral density (BMD) and severity of coronary artery calcium (CAC) score.

Methods And Results: MESA is a prospective cohort study of 6814 men and women between the ages of 45 and 84 years, without clinical cardiovascular disease. This study included participants who underwent non-contrast chest CT scans to determine CAC score and thoracic spine BMD. The thoracic spine BMD was categorized into osteoporosis (defined as T score: ≤ -2.5), osteopenia (T-score between: -2.5 and -1) and normal BMD (T-score ≥ -1). There were 3392 subjects who had CAC >0 at baseline. The prevalence of CAC >0 was 36% in normal BMD group, 49% in the osteopenia and 68% in osteoporosis group. After adjusting for risk factors of atherosclerosis, in multivariate regression models we found a significant association between CAC and osteoporosis (OR: 1.40, 95% CI 1.16-1.69, p value < 0.0004). Furthermore, we stratified our results by gender and found a statistically significant association in both men and women.

Conclusion: Results from this cross-sectional analysis of a large population based ethnically diverse cohort indicate a significant inverse relationship between thoracic BMD and CAC in both genders independent of other cardiovascular risk factors. Future studies need to explore the underlying pathophysiological mechanisms relating BMD and coronary artery calcification.