Relation between XbA1 apolipoprotein B gene polymorphism and cardiovascular risk in a type 2 diabetic cohort

Aim: To evaluate in a prospective study the association of XbA1 apolipoprotein B (apoB) gene polymorphism with lipid parameters and cardiovascular (CV) events in a type 2 diabetic cohort. Methods and results: A cohort of 212 type 2 diabetic patients, free of any cardiovascular complication, was studied. Cardiovascular events were registered for all the patients for 5 years. XbA1 apolipoprotein B gene polymorphism was analysed by PCR-RFLP method. A mild increase in HbA1c was found in X+X+ carriers (P=0.014). Despite this lower glycemic control, there were no differences between genotype subgroups for lipid parameters except for apoB, significantly higher in X+X+ than in X–X– subjects. In univariate analysis, the cardiovascular events rate was higher in X–X– but did not reach statistical significance (P=0.07). In stepwise multivariate regression analysis, cardiovascular events risk was significantly higher in X– carriers (P=0.014) and also in smokers, microalbuminuric and older patients. Conclusions: We report for the first time in a prospective study the association of XbA1 apolipoprotein B gene polymorphism and cardiovascular events in a diabetic population. The mechanism underlying the excess of cardiovascular risk in X– carriers, despite a better metabolic profile, is likely to involve a linkage disequilibrium between apolipoprotein B gene locus and another gene locus related to cardiovascular risk.