VEGF-634G>C polymorphism and diabetic retinopathy risk: A meta-analysis

Background: Vascular endothelial growth factor (VEGF), a multifunctional cytokine that promotes angiogenesis and is a potent mediator of microvascular permeability, which is critical for the development of diabetic retinopathy (DR). It has demonstrated that VEGF - 634G>C (rs2010963) polymorphism alters the transcriptional activity of the gene. However, studies on the association between VEGF - 634G>C polymorphism and DR in type 2 diabetes have reported conflicting results. Thus, the aim of the present study was to investigate whether VEGF - 634G>C polymorphism is associated with the risk of DR in type 2 diabetes. Methods: A systematic search of electronic databases (PubMed, Embase and Web of Science) and reference lists of relevant articles was carried out until September 15, 2012. The pooled odds ratios (ORs) and their corresponding 95% confidence interval (CI) were calculated by a fixed effect model. Results: A total of 1525 DR cases and 1422 diabetic without retinopathy (DWR) controls in 9 independent studies were included in the meta-analysis. A significant relationship between VEGF - 634G>C polymorphism and DR was found in an allelic genetic model (OR: 1.13, 95% CI: 1.01 to 1.25, P = 0.03) and a recessive genetic model (OR: 1.26,95% CI: 1.02 to 1.55, P = 0.03). Conclusion: Our research confirmed the association between the VEGF - 634G>C polymorphism and DR in subjects with type 2 diabetes. Well-designed studies with larger sample size and more ethnic groups are required to further validate the results. (C) 2013 Elsevier B.V. All rights reserved.