title: Nitric oxide synthase 3 (NOS3) 4b/a, T-786C and G894T polymorphisms in association with diabetic retinopathy susceptibility: a meta-analysis.
abstract: OBJECTIVE
  To assess the association between the NOS3 4b/a, T-786C and G894T polymorphisms and diabetic retinopathy (DR) susceptibility.
  
  
  METHODS
  Twenty-one studies covering 8,111 subjects were included. The fixed or random effect model used was based on heterogeneity.
  
  
  RESULTS
  A significant association of the intron 4a allele in the NOS3 4b/a polymorphism with reduced risk of DR was found in dominant (OR 0.778, 95% CI 0.654-0.926) and additive (OR 0.809, 95% CI 0.698-0.937) models. Subgroup analysis revealed that the intron 4a allele additive model (OR 0.807, 95% CI 0.697-0.935) was associated with DR risk in type 2 diabetic patients. We also found a marginally significant association of the C allele in the T-786C polymorphism with reduced risk of proliferative DR. In contrast, no statistically significant association was observed between the G894T polymorphism and DR risk, either in the overall or subgroup analyses.
  
  
  CONCLUSIONS
  The intron 4a allele of the 4b/a polymorphism in the eNOS gene has protective effects against DR, especially in type 2 diabetic patients. The C allele of the T-786C polymorphism may be a protective factor for proliferative DR. However, the G894T polymorphism does not appear to influence the development of DR. This conclusion warrants confirmation by further studies.
authors.affiliation: Department of Ophthalmology, First People's Hospital of Shanghai, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Shuzhi
authors.initials: S
authors.lastname: Zhao
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Bingqing
authors.initials: B
authors.lastname: Zheng
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zheng
mesh_terms: D000483:Alleles; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics; D003930:Diabetic Retinopathy / Q000235:genetics* / Q000517:prevention & control; D004198:Disease Susceptibility; D005260:Female; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D008875:Middle Aged; D052250:Nitric Oxide Synthase Type III / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide
chemical_list: C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III