Abstract P122: Racial/Ethnic Variation in Incidence and Progression of Coronary Artery Calcification: Implications for Understanding the Hispanic Paradox

Abstract

Background: Previous studies show that Hispanic persons have similar or lower levels of coronary artery calcium (CAC) and slower progression than non-Hispanic whites (NHW), even after adjustment for traditional risk factors. We examined whether this health advantage in CAC incidence and progression among Hispanic adults extends across all levels of risk factor (RF) burden, and whether associations vary by nativity (foreign-born, US-born) and by heritage group (Mexican, non-Mexican). Methods: We analyzed data on Hispanic and NHW participants aged 45-84 years from the Multi-Ethnic Study of Atherosclerosis (MESA). Follow-up CAC measurements and complete covariate data were available for 3694 participants with an average of 6.6 years between the follow-up and baseline scans (2000-2002). Baseline measures of the following traditional RFs were considered: current cigarette smoking, high total cholesterol, hypertension, diabetes, and obesity, with RF burden scores ranging from 0-5. Outcomes were incident CAC (any follow-up CAC >0 Agatston units) among individuals without detectable CAC at baseline, and CAC progression (any positive increase in CAC) among all participants estimated using relative risk regression. All models were adjusted for age, sex, RF burden, race/ethnicity, education, income, and time between scans Results: Although a higher proportion of Hispanics had RF burden scores ≥3 compared to NHW (14.6% vs 8.9%, p<0.0001), Hispanics had a lower adjusted incidence (risk ratio (RR) = 0.83, 95% CI: 0.72-0.96) and less progression of CAC (RR=0.90, 95% CI: 0.86-0.95) than NHW. However, there was evidence of heterogeneity in this pattern. For example, among individuals with no detectable baseline CAC, a Hispanic health advantage was only seen among individuals with RF burden scores of 0 (RR=0.66, 95% CI: 0.48-0.91 for Hispanics vs. NHW at RF=0), with race/ethnic differences getting progressively smaller with increasing RF burden (for RF ≥3: RR=1.01, 95% CI: 0.69-1.48). Compared to NHW, lower adjusted incidence and progression of CAC was evident to an even greater extent among foreign-born Hispanics, but a health advantage was still present for US-born Hispanics, and for both Hispanic heritage groups. However, these patterns also only remained among individuals with lower RF burden scores. Conclusions: The Hispanic health advantage in CAC incidence and progression was primarily evident among individuals with fewer traditional risk factors for CVD, but was present among different Hispanics groups. Future research is necessary to identify the factors underlying this advantage, and the dynamics that erode it as RF burden increases.