Abstract MP72: Apolipoprotein B and Apolipoprotein B, LDL-C Discordance in Young Adults Are Associated With Coronary Artery Calcification at 25 Year Follow-Up: The Coronary Artery Disease in Young Adults (CARDIA) Study

Abstract

Introduction: High ApoB has been shown to predict cardiovascular disease (CVD) in adults even in the context of low LDL-C. It is not known, however, if high ApoB and high ApoB, low LDL-C discordance in young adults are associated with coronary artery calcium (CAC) in mid-life. Methods: Data were derived from CARDIA, a multicenter study of the development and determinants of CVD risk factors in young adults recruited at ages 18 to 30. All participants with complete baseline CVD risk factor data, ApoB, and year-25 CAC score were included in this study. Baseline lipid fractions and ApoB were measured by standard assays. Year-25 CAC was assessed using two consecutive CT scans with presence of CAC defined as having a positive, non-zero Agatston score using the average of two scans. Baseline ApoB values were divided into tertiles. Four mutually exclusive concordant/discordant groups were created based on median ApoB and LDL-C. Logistic regression was performed for unadjusted and adjusted models. Results: 3496 participants were included [mean age=25±3.6, BMI=24.5±5Kg/m2, 44.4% male, and the following mean lipid values (mg/dL): total cholesterol=177.3±33.1, LDL-C=109.9±31.1, HDL-C=53±12.8, ApoB=90.7±24, median triglycerides=61(IQR 46-83)]. Compared with the lowest ApoB tertile, the middle [OR=1.55 (95% CI 1.22-1.95)] and high [OR=2.35 (95% CI 1.87-2.97)] tertiles exhibited increased odds of developing year-25 CAC in traditional risk factor-adjusted models. High ApoB, low LDL-C discordance was also associated with year-25 CAC in adjusted models [OR=1.57 (95% CI 1.12-2.20)]. Conclusions: These data suggest a dose-response association between ApoB in young adults and presence of mid-life CAC independent of baseline traditional CVD risk factors. High ApoB, low LDL-C discordance was also associated with year-25 CAC, suggesting that ApoB in young adults may help identify individuals with modest LDL-C levels who are at increased risk for subclinical atherosclerosis in mid-life.