Volumetric BMD and Vascular Calcification in Middle-Aged Women: The Study of Women's Health Across the Nation

UNLABELLED: The association of spine vBMD with AC and CAC was studied in a biracial cohort of 490 middle-aged women in the Study of Women's Health Across the Nation. Lower vBMD was related to high AC, but not to CAC, independent of age and shared risk factors between osteoporosis and cardiovascular disease. INTRODUCTION: This analysis studied the association of spine volumetric BMD (vBMD) with aortic (AC) and coronary artery (CAC) calcification in middle-aged women and evaluated whether such associations were independent of age and shared risk factors between osteoporosis and cardiovascular disease (CVD) or explained by endogenous estradiol levels. MATERIALS AND METHODS: Vascular calcification and trabecular vBMD of the spine were measured using electron-beam CT in 490 women free from clinical CVD in the Study of Women's Health Across the Nation. Women were 45-58 years of age, 61% were white, and 64% were perimenopausal. Calcification scores were categorized into three levels (no AC, N = 146; moderate AC, scores = 1-74, N = 221; high AC, N = 123; no CAC, N = 256; moderate CAC, score = 1-7.54, N = 111; high CAC, N = 123). The highest categories were set at the 75th percentiles. Multinomial logistic regression was used to assess the association between vBMD (per SD) and the AC and CAC levels, with no calcification as the reference group. RESULTS: AC and CAC were detected in 70% and 48% of the population, respectively. Mean vBMD was 161.6 +/- 37.2 (SD) mg/ml. vBMD was associated with high AC in unadjusted, age-adjusted, and risk factor-adjusted analysis. Per 1 SD decrease in vBMD, the adjusted odds of high AC compared with no AC was significantly increased by 68% (95% CI, 1.06-2.68). Estradiol did not influence this association. vBMD was related to high CAC in unadjusted (OR = 1.35; 95% CI, 1.08-1.70) but not adjusted models. No associations of vBMD with moderate AC or CAC were observed. CONCLUSION: Lower vBMD was related to high AC, but not to CAC, in a biracial cohort of healthy middle-aged women independent of age and shared risk factors between osteoporosis and CVD. Further research should study possible pathophysiological links between the two conditions and the potential for common preventive and therapeutic interventions.