Association of apolipoprotein A5 concentration with serum insulin and triglyceride levels and coronary artery disease in Korean men

Objective: Whereas the relation between apolipoprotein A5 (APOA5) gene polymorphisms and triglycerides (TG) levels is well established, the associations between apoA5 concentrations, TG and coronary artery disease (CAD) remain controversial. Therefore, we investigated these relations in the setting of a case-control study involving Korean males. Methods: ApoA5, TG, insulin, free fatty acid (FFA) and lipoprotein profiles were determined using a cross-sectional design in 777 healthy controls and 367 CAD patients. Results: Plasma apoA5 concentration was lower in CAD patients than controls (192.7 ± 5.2 vs. 237.2 ± 3.7 ng/ml, P < 0.001). Values in the second and top tertiles of apoA5 were associated with a decreased odds ratio (OR) for CAD when compared with values in the bottom tertile; OR for apoA5 top tertile was 0.33 (95% CI, 0.23-0.47) in the age- and BMI-adjusted model and 0.35 (95% CI, 0.23-0.56) following additional adjustments for smoking, drinking status, blood pressure, TG and HDL-cholesterol. After adjustment for age and BMI, plasma apoA5 concentration was negatively correlated with serum TG (r = -0.188, P < 0.001) and insulin (r = -0.185, P < 0.001) in normotriglyceridemic controls (TG < 150 mg/dL, n = 509) whereas apoA5 was positively correlated with serum TG in hypertriglyceridemic controls (TG ≥ 150 mg/dL, n = 268) (r = 0.246, P < 0.001) and total CAD patients (r = 0.177, P < 0.01). Regardless of TG levels and CAD status, apoA5 concentration was positively correlated with HDL-cholesterol and FFA levels. Conclusions: Our data supports an inverse association between plasma apoA5 concentrations and CAD risk, probably due to the observed negative correlations of apoA5 with TGs and insulin, although these correlations were affected by TG levels.