Objective: The most important cause of morbidity and mortality in type 1 diabetes mellitus (DM) is atherosclerosis. Apolipoprotein E (Apo E) polymorphism is accused of being the genetic risk factor for atherosclerosis. The aim of the present study was to determine which Apo E polymorphism was related to atherosclerosis in patients with type 1 DM.
Methods: Seventy-four patients with type 1 DM were enrolled in the study. Age, diabetes duration, daily insulin dose, microalbuminuria, and major cardiovascular risk factors including anthropometric and metabolic parameters were assessed in each patient. Non-invasive ultrasonographic measurements were also performed. For determination of Apo E genotype, DNA was extracted from venous blood from all subjects using standard methods. Apo E genotyping was performed using a PCR-restriction fragment-length polymorphism assay.
Results: Systolic blood pressure and carotid artery intima-media thickness (CA-IMT) were increased in subjects with E4/E4 polymorphism. According to univariate analysis, when adjusted for all risk factors, genotypes did not differ for total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides (p>0.05). However, E3/E3, E3/E4 and E4/E4 genotypes were found to be associated with an increase in CA-IMT (p<0.001).
Conclusions: Our results suggest that the polymorphism associated with atherosclerosis in type1 DM is Apo E4/E4.