Methylenetetrahydrofolate Reductase C677T Polymorphism and Type 2 Diabetes Mellitus in Chinese Population: A Meta-Analysis of 29 Case-Control Studies

Abstract

BackgroundMethylenetetrahydrofolate reductase (MTHFR), a key enzyme in folate metabolism, had significant effects on the homocysteine levels. The common functional MTHFR C677T polymorphism had been extensively researched. Several studies had evaluated the relationship between MTHFR C677T polymorphism and type 2 diabetes mellitus (T2DM), but the results were still controversial in the Chinese Han population. This meta-analysis was conducted to evaluate the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population.MethodsWe searched the relevant studies in multiple electronic databases, which published up to December 2013. We reviewed and extracted data from all the included studies on the relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The odds ratios (ORs) and their 95% confidence intervals (95%CIs) were used to evaluate the relationship. Fixed-effects and random-effects meta-analysis were used to pool ORs by the heterogeneity. Publication bias and sensitivity analysis were also examined.Results29 studies were finally included in our meta-analysis, which contained 4656 individuals with T2DM and 2127 healthy controls. There was a significant relationship between MTHFR C677T polymorphism and T2DM under dominant (OR: 1.70, 95% CI: 1.42–2.02), recessive (OR: 1.48, 95% CI: 1.21–1.80), homozygous (OR: 1.89, 95% CI: 1.47–2.42), heterozygous (OR: 1.58, 95% CI: 1.33–1.87), and additive (OR: 1.46, 95% CI: 1.28–1.68) genetic model in a random-effects model. Subgroup analysis also reached similar results. Sensitivity analysis indicated that the overall result were dependable.ConclusionsThere was a significant relationship between MTHFR C677T polymorphism and T2DM in the Chinese Han population. The results of our meta-analysis suggested that MTHFR 677T allele might be a risk genetic factor of T2DM in the Chinese Han population.

Additive Interaction of MTHFR C677T and MTRR A66G Polymorphisms with Being Overweight/Obesity on the Risk of Type 2 Diabetes

“…A recent meta-analysis of 29 epidemiologic studies demonstrated that there was a significant association between the MTHFR C677T polymorphism and T2D in the Chinese Han population [39]. Our data suggested that the MTHFR 677TT genotype was associated with a higher risk of T2D than the CC genotype, and the direction and magnitude of the association were consistent with those reported in previous excellent meta-analyses [11,40]. …”

Methylenetetrahydrofolate Reductase C677T Polymorphism and Recurrent Pregnancy Loss Risk in Asian Population: A Meta-analysis

“…Because of the large sample sizes, metaanalysis has more statistical power than a single study to obtained reliable result. Several large-scale meta-analyses combining data from multiple studies have been published investigating the association between MTHFR C677T polymorphism and various disease/disorders such as- Down syndrome [66], Neural Tube defects [67], cleft lip with/without palate [68], congenital heart defects [69], stroke [70], diabetes mellitus [71], Alzheimers disease [72], schizophrenia [73] and cancer [74].…”

Opposite impact of Methylene tetrahydrofolate reductase C677T and Methylene tetrahydrofolate reductase A1298C gene polymorphisms on systemic inflammation

“…It is believed that this 2 gene polymorphisms affect 30%‐50% of general population and are related with increased risks for many diseases. MTHFR C677T polymorphism was found to be related with diabetes, insulin resistance, risk of coronary artery disease (CAD), premature CAD, and severity of CAD . In a meta‐analysis, C677T polymorphism was shown to be associated with the risk of myocardial infarction (MI) in African, North American, and elderly populations .…”