Objective: The purpose of this study was to evaluate the effect of the single nucleotide polymorphism (SNP) -634G>C at the 5' regulatory region of the vascular endothelial growth factor (VEGF) in the risk of proliferative diabetic retinopathy (PDR) in the Brazilian population of European ancestry with type 2 diabetes.
Research design and methods: A case-control study was conducted in 501 type 2 diabetic patients of European ancestry. Patients underwent a standardized clinical, ophthalmological, and laboratory evaluation. Of these, 167 patients had PDR (case patients), and 334 were considered as control subjects (patients without PDR) for PDR. A reference population (110 individuals of European ancestry) was also evaluated.
Results: No evidence of association between -634G>C/VEGF and the presence of diabetic retinopathy or type 2 diabetes was observed (P > 0.05). However, CC homozygous for the SNP -634G>C was significantly more frequent in patients with PDR (37 of 167; 22.2%) than in the corresponding control group (40 of 334; 12%) in accordance with a recessive model (P = 0.003). This effect was further observed when creatinine, BMI, sex, duration of type 2 diabetes, HDL cholesterol, and systolic blood pressure were taken into account (odds ratio 1.9 [95% CI 1.01-3.79], P = 0.04).
Conclusions: The presence of the allele -634C/VEGF in homozygosity is an independent risk factor for the development of PDR in type 2 diabetic patients of European ancestry.