Polymorphisms of eNOS gene are associated with diabetic nephropathy: a meta-analysis

The aim of the current study is to assess the association between the alleles of endothelial nitric oxide synthases (eNOS) gene 4b/a, G894T, T786C polymorphisms and diabetic nephropathy (DN) through meta-analyses. We also performed a subgroup analysis based on ethnicity (Caucasians, East-Asian and other populations). A total of 3793 patients (DN) and 3161 controls (diabetes without nephropathy) for 4b/a, 2654 patients and 1993 controls for G894T and 1348 patients and 1175 controls for T786C were included in our analysis. Overall, allele contrast (4a versus 4b) of 4b/a polymorphism produced significant results in the global population [random effects model (RE) odds ratio (OR) = 1.33; 95% confidence interval (CI) = 1.10-1.61, P = 0.003] and East-Asian population (RE OR = 1.68; 95% CI = 1.23-2.30, P = 0.001), but not in the Caucasian population. In allele contrast of G894T, an obvious significant result was observed in the East-Asian population [fixed effects model OR = 1.69; 95% CI = 1.37-2.08, P < 0.0001], but not in the Caucasian population. Sensitivity analyses generated similar results to those of the primary analyses. The evidence accumulated suggested that 4b/a and G894T polymorphisms in the eNOS gene were associated with susceptibility to DN in Asian populations, but not in Caucasian populations.