Is reduced bone mineral density independently associated with coronary artery calcification in subjects older than 50 years?

It has not been clearly defined whether reduced bone mineral density (BMD) is a direct risk factor of vascular calcification. A total of 2,160 subjects who were older than 50 years and underwent routine health examination at the Seoul National University Hospital Healthcare System Gangnam Center were included in this study. Coronary artery calcium scores (CACS) were calculated to quantify the extent of coronary artery calcification (CAC) using computed tomography. Bone dual-energy X-ray absorptiometry was also performed in all the subjects. BMD was classified as normal, osteopenia, or osteoporosis according to the lowest T score in the lumbar spine, femoral neck, or total hip. The mean value of CACS was 66.1 +/- A 234.0, and 1,372 subjects (63.5%) showed no coronary artery calcium deposits. A gender difference in the association between BMD and CACS was observed; a significant relationship was identified only in women. Unadjusted odds ratio for the presence of CAC in female subjects with reduced BMD was 1.925 (95% CI 1.383-2.679, p < 0.001). However, after adjusting for age and other risk factors, the association was no longer significant. Age, hypertension, glucose, and male gender were independent factors determining CAC in multiple regression analysis. Although reduced BMD and CAC were common findings among the elderly, the close association between them diminished after considering other factors affecting CAC.