Association of Abdominal Aorta Calcium and Coronary Artery Calcium with Incident Cardiovascular and Coronary Heart Disease Events in Black and White Middle-Aged People: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND: Assessing coronary artery calcium (CAC) is among AHA/ACC prevention guidelines for people at least 40 years old at intermediate risk for coronary heart disease (CHD). To study enhanced risk stratification, we investigated the predictive value of abdominal aorta calcium (AAC) relative to CAC for cardiovascular disease (CVD) and CHD events in Black and White early middle-aged participants, initially free of overt CVD. METHODS AND RESULTS: In the CARDIA (Coronary Artery Risk Development in Young Adults) study, a multi-center, communitybased, longitudinal cohort study of CVD risk, the CAC and AAC scores were assessed in 3011 participants in 2010– 2011 with follow-up until 2019 for incident CVD and CHD events. Distributions and predictions, overall and by race, were computed. During the 8-year follow-up, 106 incident CVD events (55 were CHD) occurred. AAC scores tended to be much higher than CAC scores. AAC scores were higher in Black women than in White women. CAC predicted CVD with HR 1.77 (1.52– 2.06) and similarly for AAC, while only CAC predicted CHD. After adjustment for risk factors and calcium in the other arterial bed, the association of CAC with CVD was independent of risk factors and AAC, while the association of AAC with CVD was greatly attenuated. However, AAC predicted incident CVD when CAC was 0. Prediction did not vary by race. CONCLUSIONS: AAC predicted CVD nearly as strongly as CAC and could be especially useful as a diagnostic tool when it is an incidental finding or when no CAC is found.