Methylenetetrahydrofolate reductase C677T polymorphism and diabetic retinopathy risk: a meta-analysis of the Chinese population

OBJECTIVES: This study evaluated associations between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms and diabetic retinopathy (DR) susceptibility within the Chinese population. METHODS: Five databases (PubMed, EMBASE, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure) were used for literature searches of open access articles from inception through April 2017. RESULTS: Eight publications were identified involving 600 DR cases, 363 healthy controls, and 646 nondiabetic retinopathy (NDR) controls. There was a positive association between MTHFR C677T polymorphisms and DR risk within the Chinese population (DR with NDR controls: T vs. C, odds ratio (OR): 2.14, 95% confidence interval (CI): 1.55–2.97; TT vs. CC, OR: 4.19, 95% CI: 2.09–8.41; TT + CT vs. CC, OR: 2.83, 95% CI: 1.86–4.40; TT vs. CC + CT, OR: 2.48, 95% CI: 1.52–4.05. DR with healthy controls: T vs. C, OR: 2.48, 95% CI: 1.99–3.09; TT vs. CC, OR: 4.92, 95% CI: 3.18–7.62; TT + CT vs. CC, OR: 3.22, 95% CI: 2.32–4.48; TT vs. CC + CT, OR: 3.11, 95% CI: 1.83–5.28). The association was similar in South China and North China, when stratifying by geographic areas. CONCLUSION: MTHFR C677T polymorphisms increase DR risk within the Chinese population.