Remnant Cholesterol and the Risk of Coronary Artery Calcium Progression: Insights From the CARDIA and MESA Study

BACKGROUND: Remnant cholesterol (RC) contributes to residual risk of atherosclerotic cardiovascular disease, but population-based evidence on the prospective relationship between RC and coronary artery calcium (CAC) progression is rare. METHODS: We pooled data obtained from 6544 atherosclerotic cardiovascular disease-free individuals from the CARDIA study (Coronary Artery Risk Development in Young Adults; n=2635) and MESA (Multi-Ethnic Study of Atherosclerosis; n=3909), with a mean +/- SD age of 47.2 +/- 19.8 years; 3019 (46.1%) were men who completed computed tomography of CAC at baseline. RC was measured as total cholesterol minus HDL (high-density lipoprotein) cholesterol minus calculated LDL (low-density lipoprotein) cholesterol (LDL-C) estimated by using the Martin/Hopkins equation. Adjusted Cox models were used to assess the relationships between RC levels and CAC progression. We also performed discordance analyses examining the risk of CAC progression in RC versus LDL-C discordant/concordant groups using median cut points and clinically relevant LDL-C targets. RESULTS: During a median follow-up of 8.6 years, 2778 (42.5%) participants had CAC progression. After multivariable adjustment for demographics and cardiovascular risk factors, a 1-mg/dL increase in RC levels was associated with a 1.3% higher risk of CAC progression (hazard ratio, 1.013 [95% CI, 1.008-1.017]). Results were similar when we categorized individuals by RC quartiles. Furthermore, the discordant high RC/low LDL-C group had a significantly higher risk of CAC progression than the concordant low RC/LDL-C group regarding their medians (hazard ratio, 1.195 [95% CI, 1.063-1.343]) or when setting the clinical LDL-C cut points at 100 and 130 but not 70 mg/dL. The association remained robust across a series of sensitivity analyses. CONCLUSIONS: Elevated RC levels were associated with an increased risk of CAC progression independent of traditional cardiovascular risk factors, even in individuals with optimal LDL-C levels.