title: Association of glutathione peroxidase-1 (GPx-1) rs1050450 Pro198Leu and Pro197Leu polymorphisms with cardiovascular risk: a meta-analysis of observational studies.
abstract: OBJECTIVE
  To clarify the association between rs1050450 polymorphism in Glutathione peroxidase-1 (GPx-1) and the risk of cardiovascular diseases (CVD) by performing a meta-analysis of published studies. There is growing evidence from different study types for an association of the GPx-1 polymorphism and cardiovascular outcomes, but observational studies have so far shown inconsistent results.
  
  
  METHODS
  Relevant publications were searched through PubMed, Embase database databases and the Cochrane Library. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of association under the best genetic model. Both Q statistic and the I (2) were used to check heterogeneity. Meta-regression analysis was performed to explore heterogeneity source. Sensitivity analysis, cumulative meta-analysis analysis and publication bias were used to test the reliability of the results.
  
  
  RESULTS
  Data were available from two cohort studies and 8 case-control studies involving 1,430 cases and 3,767 controls. The pooled ORs for overall CVD risk was 1.36 with 95% CI: 1.08-1.70 under a co-dominant model, and that for East Asian subgroup was 1.84 (95% CI: 1.39-2.43). Substantial heterogeneity for ORs were detected among all the included studies, mainly caused by ethnic differences between East Asian and non-East Asian populations. Although Egger's regression test suggested no statistical significant publication bias, Begg's funnel plot exhibited obvious asymmetry. The statistical significance disappeared after adjusting for potential publication bias in the overall studies. However, no substantial publication bias was found in the East Asian subgroup.
  
  
  CONCLUSIONS
  GPx-1 gene Pro198Leu and Pro197Leu polymorphisms considerably increased the risk of CVD in the East Asian population. Large-scale investigations are needed to confirm the results in different ethnicities.
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Jun-Xia
authors.initials: JX
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Zhi-Mei
authors.initials: ZM
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Lin-Lin
authors.initials: LL
authors.lastname: Zhu
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Gao
authors.affiliation: Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu Province 210006, China.
authors.forename: Shao-Liang
authors.initials: SL
authors.lastname: Chen
keywords: Cardiovascular diseases; Glutathione peroxidase-1; Meta-analysis; Polymorphism