The relationship between methylenetetrahydrofolate reductase C677T polymorphism and diabetic retinopathy: A meta-analysis in multiethnic groups

ABSTRACTBackground: Many studies have analyzed the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and diabetic retinopathy (DR), however, the results remained inconclusive. We therefore aim to address this association by performing a meta-analysis in multiethnic groups. Methods: Related studies were identified from PubMed and Chinese databases up to October 2016. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations.Results: A total of 20 studies including 1860 DR cases and 3646 controls were involved in this meta-analysis. In the overall population, we found that MTHFR C677T polymorphism was significantly associated with an increased risk of DR for each genetic model. In this meta-analysis stratified by ethnicity, significantly increased risk of DR with the MTHFR C677T variants was found in the Chinese, Japanese, and Turks populations.Conclusions: Our study suggested that the MTHFR C677T polymorphism may contri...