Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and susceptibility to diabetic nephropathy in Chinese type 2 diabetic patients: a meta-analysis

The association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and diabetic nephropathy (DN) or diabetes mellitus (DM) risk has been widely reported, but the results are still debatable. To investigate the role of MTHFR C677T polymorphism on DM or DN, 13 separate studies in the Chinese population on the relation between MTHFR C677T polymorphism and DM or DN were analyzed by a meta-analysis. Five genetic models were used to estimate the association between MTHFR C677T polymorphism and the risk of DM or DN. Overall, our meta-analysis for DN versus healthy controls produced significant results for all genetic contrasts except for the co-dominant model (allele contrast: OR = 2.24, 95% CI: 1.88-2.65, p<0.00001, P-heterogeneity = 0.49). However, the meta-analysis for DM versus healthy controls produced non-significant results for all contrasts (allele contrast: OR = 1.12, 95% CI: 0.92-1.35, p = 0.25, P-heterogeneity = 0.07). In addition, the meta-analysis for DM versus DN produced significant results for all contrasts (allele contrast: OR = 1.88, 95% CI: 1.65-2.15, p<0.00001, P-heterogeneity = 0.83). The current meta-analysis suggested that MTHFR C677T polymorphism might influence DN risk, but not for DM in the Chinese population.