Relationship Between the ApoE Gene Polymorphism and Type 2 Diabetes Mellitus Complications

Background: Apolipoprotein E (ApoE) polymorphisms are associated with type 2 diabetes mellitus (T2DM) and its complications, but studies have shown conflicting results. Objective: To examine the relationship of ApoE gene polymorphisms with T2DM and its complications. Materials and Methods: This case–control study of patients with T2DM was conducted between June 2016 and July 2019. Healthy individuals were recruited as controls. The patients were grouped according to coronary heart disease (CHD), cerebral infarction (CI), diabetic nephropathy (DN), and neurological complications. The ApoE genotype was determined using a commercial gene chip. Results: Compared with controls, the frequencies of genotype ɛ3/4 (20.8% vs. 11.7%, p = 0.04) and allele ɛ4 (14.3% vs. 8.3%, p = 0.03) of patients with T2DM were higher. The frequency of genotype ɛ3/4 was higher in the T2DM with CHD group (30.4% vs. 17.4%, p = 0.01 vs. non-CHD) and in T2DM with CI (29.2% vs. 18.1%, p = 0.045 vs. non-CI). The frequency of genotype ɛ2/3 was higher in the T2DM with DN group (19.3% vs. 9.1%, p = 0.01 vs. non-DN). There were no significant differences between T2DM with and without neuropathy (p > 0.05). Conclusion: The ApoE allele ɛ4 may be a risk factor for T2DM, CHD in T2DM, and CI in T2DM, while the ApoE allele ɛ2 may be a risk factor for DN.