Abstract 12101: Family History of Coronary Heart Disease and Coronary Artery Calcium in South Asians and 4 Other Racial/Ethnic Groups in the US: The Mediators of Atherosclerosis in South Asians Living in America study and the Multi-Ethnic Study of Atherosclerosis

Introduction: High coronary heart disease (CHD) rates among South Asians (SAs) are not fully explained by traditional risk factors. The association of a family history of CHD (FH) with subclinical atherosclerosis as measured by coronary artery calcium (CAC) in SAs is unknown. Hypothesis: FH is significantly and independently associated with CAC presence and burden in SAs and other ethnicities. Methods: We included all participants aged 45-84 years from two community-based populations: the MASALA study of SAs and the MESA study of Non-Hispanic Whites (NHWs), African Americans (AAs), Chinese Americans (CAs), and Hispanics (HPs). All participants underwent baseline CAC scanning. FH was defined as a self-reported history of CHD in a first-degree relative. We used multivariable regression models to assess the association of FH with CAC (>0 and >100) and likelihood ratio tests to assess the incremental predictive ability of FH to identify CAC (>0 and >100) when added to the 2013 ACC/AHA ASCVD risk estimate in each racial/ethnic group. Results: Baseline demographics are shown in the table. NHWs, AAs, and HPs with a FH had a significantly higher proportion of CAC>0 and CAC>100 than those without FH. In unadjusted and multivariable analyses, FH was significantly associated with CAC burden in NHWs, AAs, and HPs, but not in CAs or SAs (Table). Similarly, FH significantly added to the ASCVD risk estimate in predicting prevalent CAC>0 and CAC>100 in NHWs, AAs, and HPs (p-values <0.01 for all), but not in CAs (p-value 0.151 and 0.362) or in SAs (p-value 0.778 and 0.216, respectively). In a sensitivity analysis, FH was significantly associated with very high CAC>400 in SAs, but not in CAs. Conclusion: FH was strongly and independently associated with CAC burden in NHWs, AAs, and HPs; this association was weaker and non-significant in CAs and SA in the US. Understanding the reasons behind these findings will require evaluation in larger populations of CAs and SAs with detailed ascertainment of FH.