Methylenetetrahydrofolate reductase C677T gene polymorphism and coronary artery disease in a Chinese Han population: a meta-analysis.

Methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism has been suggested to be associated with increased coronary artery disease (CAD) risk. To explore the relationship between MTHFR C677T gene polymorphism and CAD in the Chinese Han population, a meta-analysis was performed. Fourteen separate studies were included and 2981 subjects were involved in the current meta-analysis. The pooled odds ratio (OR) between CAD size to CAD size and control size (CAD/CAD + control) and the corresponding 95% confidence interval (95% CI) between the CC and TT genotype groups were estimated by a random-effects model. Meta-regression was performed to explore the heterogeneity source. The CAD/CAD + control values were 0.45 for the CC genotype group and 0.62 for the TT genotype group. The pooled OR for the CAD/CAD + control between the CC and TT genotype groups was 0.55 (95% CI, 0.37-0.83; P(heterogeneity) = .0004, I(2) = 64.7%). These results indicated that MTHFR C677T gene polymorphism and CAD were significantly associated (P = .005) in the Chinese Han population. Publication year was detected as the main heterogeneity source. In a stratified analysis by publication year, the pooled OR was 0.76 (95% CI, 0.37-1.57; P(heterogeneity) = .0002; I(2) = 79.6%) in subgroup 1 (publication years 1999-2004). No significant association between gene polymorphism and CAD was found in this subgroup (P = .46). In subgroup 2 (publication years 2005-2011), the pooled OR was 0.39 (95% CI, 0.28-0.55; P(heterogeneity) = .53; I(2) = 0); and the association between gene polymorphism and CAD was significant (P < .00001). In the Chinese Han population, the TT genotype for the MTHFR C677T gene appeared to be associated with increased CAD risk.