Abstract P186: Quality of Total Heart Adipose Tissue May Contribute to the Presence and Extent of Coronary Artery Calcification in Women at Midlife: The Study of Women’s Health Across the Nation

Abstract

Background: The location and quantity of specific adipose tissue depots have been shown to be independent predictors of subclinical atherosclerosis. Most recently, attention has been focused on the quality of these fat depots as a novel marker of CVD risk. Adipose tissue attenuation, measured via radiodensity in computed tomography (CT) Hounsfield units (HU), is one such marker of fat quality. Our objective was to determine the cross-sectional association between total heart adipose tissue (TAT) radiodensity and coronary artery calcification (CAC) in women at midlife, a time period marked with an increase in CVD risk. Methods: Participants from the Study of Women’s Health Across the Nation (SWAN) Ectopic Cardiovascular Fat Ancillary Study were evaluated. CAC and TAT were measured using electron-beam CT. CAC was evaluated as 1) presence of CAC (CAC Agatston score >10), and 2) extent of CAC (continuous Agatston score). TAT radiodensity was evaluated as tertiles of HU (lowest tertile, -91 to -81 HU; middle tertile, -80 to -78 HU; highest tertile -77 to -67 HU). Logistic (for CAC presence) and Tobit regression (for CAC extent) were used for statistical analyses. Results: A total of 495 women with a mean age of 51 years were examined. This sample of women was 63% white, 37% black, 54% pre-/early peri-menopausal, 35% late peri-/postmenopausal, and 11% used hormones. In unadjusted logistic and Tobit regression models ( Table 1 ), the tertiles of TAT were significantly and inversely associated with the presence and extent of CAC. In fully adjusted models, the middle tertile remained significantly inversely associated with the presence and extent of CAC compared to the lowest tertile, but the adjusted estimates for the highest tertile were attenuated and non-significant ( Table 1 ). Conclusions: There appears to be an inverse relationship between TAT radiodensity and CAC which is more pronounced for those with mid-range radiodensity values. These results merit further investigation.