title: Association between TNFA Gene Polymorphisms and Helicobacter pylori Infection: A Meta-Analysis.
abstract: BACKGROUND
  Several host genetic factors are thought to affect susceptibility to Helicobacter pylori infection-related diseases, including tumor necrosis factor (TNF)-α. Previous studies have evaluated the association between TNFA gene polymorphisms and H. pylori infection, but the results were inconclusive. We conducted this meta-analysis to clarify the association between TNFA polymorphisms and H. pylori infection.
  
  
  METHODS
  Published literature within PubMed, Embase, and the Cochrane Library were used in our meta-analysis. Data were analyzed with the Stata13.1 software package using pooled odds ratios (ORs) with 95% confidence intervals (CI).
  
  
  RESULTS
  A total of 24 studies were included in our study. The TNFA -308G>A polymorphism was associated with decreasing H. pylori infection (AA vs. AG+GG, OR = 0.64, 95% CI = 0.43-0.97; AA vs. GG, OR = 0.64, 95% CI = 0.43-0.97). A significantly decreased risk was also found for -1031T>C polymorphism (CC vs. CT+TT, OR = 0.61, 95% CI = 0.44-0.84). -863C>A polymorphism was associated with increasing risk of H. pylori infection (AA+AC vs. CC, OR = 1.47, 95% CI = 1.16-1.86; A allele vs. C allele, OR = 1.40, 95% CI = 1.14-1.72). There was no significant association between -857C>T polymorphism and H. pylori infection. When stratified analysis was conducted on H. pylori infection detection methods, -857C>T and -863C>A polymorphisms were associated with H. pylori infection for the non-ELISA subgroup. When stratified for ethnicity or study design, -863C>A significantly increased the risk and -1031T>C decreased the risk for the Asian subgroup and hospital-based subgroup.
  
  
  CONCLUSIONS
  Results of our meta-analysis demonstrate that TNFA -308G>A and -1031 T>C polymorphisms may be protective factors against H. pylori infection, and -863C>A may be a risk factor, especially in Asian populations. Further studies with larger sample sizes are required to validate these results.
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Second Hospital of Gansu Province, Lanzhou, China.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Department of Gastroenterology, Second Hospital of Gansu Province, Lanzhou, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Ximei
authors.initials: X
authors.lastname: Fu
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Jing
authors.affiliation: Department of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Han
mesh_terms: D020022:Genetic Predisposition to Disease; D016481:Helicobacter Infections / Q000235:genetics*; D016480:Helicobacter pylori; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha
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