ε2 allele and ε2-involved genotypes (ε2/ε2, ε2/ε3, and ε2/ε4) may confer the association of APOE genetic polymorphism with risks of nephropathy in type 2 diabetes: a meta-analysis

Background Diabetic nephropathy (DN) contributes to end-stage renal failure. Microvascular injury resulted from reactive oxygen species is implicated in the pathogenesis of DN. Genetic polymorphism of Apolipoprotein E (APOE) influences the antioxidative properties of the protein. The relationship ofAPOEpolymorphism with the risks of nephropathy in type 2 diabetes (T2DN) remains elusive. Methods An up-to-date meta-analysis was conducted on the basis of studies selected from PubMed, WanFang database, Embase, Vip database, Web of Science, Scopus, and CNKI database. Results A total of 33 studies conferring 3266 cases and 3259 controls were selected on the basis of criteria of inclusion and exclusion in this meta-analysis. ForAPOEalleles, the pooled odds ratio (OR) of epsilon 2 vs. epsilon 3 was 1.89 (95% confidence intervals [95% CI]: 1.49-2.38,P < 0.0001). With regard toAPOEgenotypes, epsilon 2/epsilon 2, epsilon 2/epsilon 3, and epsilon 2/epsilon 4 increased the risk of T2DN (epsilon 2/epsilon 2 vs. epsilon 3/epsilon 3: OR = 2.32, 95% CI: 1.52-3.56,P = 0.0001; epsilon 2/epsilon 3 vs. epsilon 3/epsilon 3: OR = 1.97, 95% CI: 1.50-2.59,P<0.0001; epsilon 2/epsilon 4 vs. epsilon 3/epsilon 3: OR = 1.69, 95% CI: 1.18-2.44,P = 0.0046). Conclusions This meta-analysis found that theAPOE epsilon 2 allele and the epsilon 2-involved genotypes (epsilon 2/epsilon 2, epsilon 2/epsilon 3, and epsilon 2/epsilon 4) are the risk factors of T2DN.