Association between the -634 C/G polymorphisms of the vascular endothelial growth factor and retinopathy in type 2 diabetes: A meta-analysis

AimsTo investigate the association of vascular endothelial growth factor (VEGF) -634 C/G polymorphism with retinopathy in type 2 diabetes.Methods8 studies with 1183 cases and 1057 controls were included. Allelic and genotypic comparisons between cases and controls were evaluated.ResultsOur meta-analysis did not suggest a significant association of the -634 C/G polymorphism with diabetic retinopathy (DR) and proliferative diabetic retinopathy (PDR) (P > 0.05). The pooled odds ratios (ORs) for allelic frequency comparison, recessive model comparison, dominant model comparison, and additive model showed that the -634 C/G polymorphism is significantly associated with nonproliferative diabetic retinopathy (NPDR): OR = 1.61 [95% confidence interval (CI, 1.23, 2.10)], P = 0.0005, Pheterogeneity = 0.38, OR = 2.24 [95% CI (1.15, 4.39)], P = 0.02, Pheterogeneity = 0.24, OR = 1.87 [95% CI (1.01, 3.48)], P = 0.05, Pheterogeneity = 0.16, and OR = 2.91 [95% CI (1.33, 6.39)], P = 0.008, Pheterogeneity = 0.26, respectively. However, in sensitivity analyses, we only detected a marginally significant association of the C allele with NPDR: OR = 1.54 [95% CI (1.00, 2.39)], P = 0.05, Pheterogeneity = 0.17.ConclusionsOur meta-analysis does not support the association of the VEGF -634 C/G polymorphism with DR and PDR. Significant association between this polymorphism and NPDR was detected in this meta-analysis. However, this association is not robust and could be due to chance.