Lack of association between MTHFR C677T Gene polymorphism with alcohol dependence: A meta-analysis of case-control studies

Many studies have reported that MTHFR C677T (rs 1801133) polymorphism is associated with the risk of alcohol dependence(AD). However, there are conflicting results regarding this relationship. In this article, we performed a meta-analysis of case-control studies to assess synthetically the influence of MTHFR C677T polymorphism on the risk of AD. All relevant studies were searched from Cochrane Library, EmBase, PubMed, and Web of science. 7 studies were included to evaluate the strength of associations between the MTHFR C677T polymorphism and AD by pooled odds ratios (ORs) and 95% confidence intervals (CIs). The present meta-analysis evaluated a total of 1066 AD patients and 1049 controls and showed that MTHFR C677T polymorphism was not significantly associated with AD susceptibility in all five genetic models (Allelic, T vs C: OR = 1.04,95% CI: 0.83-1.31, P = 0.73; Homozygous, TT vs CC: OR = 0.98,95% CI: 0.57-1.68, P = 0.94; Heterozygous, TT vs CT: OR = 0.87,95% CI: 0.64-1.19, P = 0.39; Dominant, TT + CT vs CC: OR = 1.12,95% CI: 0.92-1.35, P = 0.26; Recessive, TT vs CT + CC: OR = 0.93,95% CI: 0.58-1.47, P = 0.74). On subgroup analysis by ethnicity, there was still insignificant association was detected in the Caucasians and Asians under the five genetic models respectively. In conclusion, the present data revealed that MTHFR C677T polymorphism may not be associated with AD susceptibility. Further well designed studies in a larger population and biological functional analysis of MTHFR are needed to elucidate the role of MTHFR C677T Gene polymorphism in AD.