title: Association between MTHFR C677T polymorphism and depression: An updated meta-analysis of 26 studies.
abstract: BACKGROUND
  Previous studies concerning the association between the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and depression have provided inconclusive findings. A meta-analysis was therefore performed to investigate a more reliable estimate.
  
  
  METHODS
  This meta-analysis recruited 26 published studies which were selected by a search of electronic databases up to January 2013, including 4992 depression cases and 17,082 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between MTHFR C677T polymorphism and depression susceptibility using random effect models.
  
  
  RESULTS
  Meta-analyses results suggested that MTHFR C677T polymorphism contributed to the increased depression risk in overall populations (for T vs. C: OR=1.19, 95%CI=1.07-1.32; for TT+CT vs. CC: OR=1.15, 95%CI=1.01-1.31; for TT vs. CC: OR=1.42, 95%CI=1.16-1.75; for TT vs. CT+CC: OR=1.38, 95%CI=1.16-1.63). Subgroup analysis by ethnicity indicated an association in Asian populations (for T vs. C: OR=1.36, 95%CI=1.11-1.66; for TT+CT vs. CC: OR=1.32, 95%CI=1.03-1.69; for TT vs. CC: OR=1.88, 95%CI=1.26-2.79; for TT vs. CT+CC: OR=1.76, 95%CI=1.30-2.38); and a marginal association in White populations (for TT vs. CT+CC: OR=1.15, 95%CI=1.01-1.31). However, the association between the MTHFR C677T polymorphism and depression was not observed in the elderly.
  
  
  CONCLUSIONS
  The MTHFR C677T polymorphism was associated with an increased risk of depression, especially in Asian populations. However, there was no evidence indicating a correlation in the elderly.
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Anhui Medical University, No. 81 Meishan road, Hefei, Anhui 230032, China.
authors.forename: Yi-Le
authors.initials: YL
authors.lastname: Wu
authors.forename: Xiu-Xiu
authors.initials: XX
authors.lastname: Ding
authors.forename: Ye-Huan
authors.initials: YH
authors.lastname: Sun
authors.forename: Hui-Yun
authors.initials: HY
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Xue
authors.initials: X
authors.lastname: Zhao
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Jiang
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Lv
authors.forename: Zhen-Qiang
authors.initials: ZQ
authors.lastname: Wu
mesh_terms: D044466:Asian People / Q000208:ethnology / Q000235:genetics*; D003866:Depressive Disorder / Q000208:ethnology / Q000235:genetics*; D056726:Genetic Association Studies / Q000379:methods*; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D044465:White People / Q000208:ethnology / Q000235:genetics*
chemical_list: C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: 5,10-methylenetetrahydrofolate reductase; CIs; Depression; HWE; Hardy–Weinberg equilibrium; MTHFR; Meta-analysis; Methylenetetrahydrofolate reductase; ORs; Odds ratios; Polymorphism; confidence intervals