Association between plasma lipids, and apolipoproteins and coronary artery disease: a cross-sectional study in a low-risk Korean population

BACKGROUND: Due to the lower level of the traditional lipid profiles in Koreans than in the series of patients from the western countries, the need to investigate other lipid parameters to help identify the individuals at high risk of CAD has been emphasized. AIM AND METHODS: To investigate whether apolipoprotein B (apo B), apolipoprotein A-I (apo A-I) and their ratio give additional information to the traditional lipid risk factors for discriminating the individuals at high-risk for coronary artery disease (CAD), 544 subjects, who met the lipid criteria of total cholesterol (TC) <230 mg/dl, low-density lipoprotein cholesterol (LDL-C) <120 mg/dl and high-density lipoprotein cholesterol (HDL-C) >40 mg/dl were recruited. Patients were considered to be CAD(+) if they had > or =50% stenosis in at least one coronary artery. RESULTS: In men, TC and apo B/apo A-I ratio were significantly different between groups with and without CAD after adjusting for age and diabetes (P = 0.037 and 0.035), and in women, triglyceride (TG), HDL-C and apo B/apo A-I ratio were significantly different after adjusting for age, diabetes and smoking status (P = 0.006, 0.007 and 0.030, respectively). In the lowest quartile of TC, TG and LDL-C, and the highest quartile of HDL-C, only apo B/apo A-I ratio was associated with CAD in both men and women. The only variable showing a significant difference between patients with and without CAD was apo B/apo A-I ratio. In models assessing whether apolipoproteins give additional information to traditional lipid risk factors, HDL-C, LDL-C, apo B/apo A-I ratio and in women but not in men, TG and apo B were all independent markers for the presence of CAD. Among the nontraditional lipid factors, only apo B/apo A-I ratio showed its additional value for identifying the presence of CAD. CONCLUSION: Apo B/apo A-I ratio is the only variable that differentiates the patients with CAD from those without and, furthermore, gives additional information to that supplied by traditional lipid risk factors in a low-risk Korean population.