UCLA

Background

Coronary artery calcium (CAC) predicts atherosclerotic cardiovascular disease (ASCVD) events, inclusive of coronary heart disease (CHD) and stroke, and is a decision-making aid for primary prevention. The predictive value of CAC categories for CHD and stroke separately and across sex and race groups of an asymptomatic population is unclear.

Methods

White, Black, and Hispanic participants of MESA (Multi-Ethnic Study of Atherosclerosis) and DHS (Dallas Heart Study) underwent CAC measurement at enrollment and were followed for incident ASCVD events. Ten-year CHD-to-stroke incidence ratios across CAC score categories 0, 1 to 99, and ≥100 were assessed. Associations of CAC with incident CHD and stroke events were evaluated using multivariable-adjusted Cox models and multiplicative interactions of CAC with sex/race were tested.

Results

Among 7042 participants (mean age, 57 years, 54% women, 36% Black, 23% Hispanic, 49% CAC=0, 19% CAC ≥100), 574 incident ASCVD events (333 CHD and 241 stroke) were observed over 12.3-year follow-up. Ten-year CHD-to-stroke incidence ratio increased significantly across CAC categories in men, women, Whites, Blacks, and Hispanics (all P<0.001). High CAC burden (score ≥100) was independently associated with ASCVD and CHD risk in all groups and with stroke risk in the overall cohort and Blacks. No sex- or race-based CAC interactions for ASCVD, CHD, and stroke events were observed. Adding CAC to a traditional risk factor model improved risk discrimination and reclassification for CHD but not for stroke events.

Conclusions

In 2 population-based cohorts of asymptomatic individuals, 10-year CHD-to-stroke incidence ratio was higher with increasing CAC score categories across sex and race groups, and CAC was consistently a better predictor of CHD than stroke. High CAC burden comparably associated with ASCVD risk across sex and race groups.