Is increased apolipoprotein B-A major factor enhancing the risk of coronary artery disease in type 2 diabetes?

ABSTRACT

OBJECTIVES: An association of Apolipoprotein B (Apo B) with coronary artery disease (CAD) independent of LDL cholesterol (LDLc) concentrations has been reported in white population. This analysis was taken up to study whether the higher CAD risk in Asian Indians with diabetes could be explained by possible alterations in Apo B and Apolipoprotein A1 (Apo A1) concentrations. METHODS: The study group consisted of four hundred and forty seven men aged > or = 25 years, 167 with CAD and 280 with no CAD, classified by coronary angiography. Plasma lipid profile including total cholesterol, LDLc, Apo A1 and Apo B were done. Glucose tolerance was evaluated in all. RESULTS: Age, BMI, Apo B, and Apo A1 were significantly associated with CAD in a multiple regression analysis. Hyper Apo B was more common than hyper LDLc in CAD (73.6% vs 20.4%, chi2 = 157, P < 0.001). Apo B concentrations were increased in diabetic subjects even in the presence of normal levels of LDLc and in the absence of CAD. CONCLUSIONS: The study has shown that the apolipoproteins B and A1 provide better information regarding the risk of CAD. Apo B abnormalities exist in large percentages of CAD subjects despite having normal levels of LDLc. Diabetes per se enhances the Apo B concentrations and this could probably be one of the mechanisms of accelerated CAD in diabetes. Hyper Apo B may be an index of CAD risk.