title: Meta-analysis: polymorphisms in TNF-alpha gene promoter and Crohn's disease.
abstract: BACKGROUND
  Tumour necrosis factor alpha (TNF-alpha) is involved in the pathogenesis of Crohn's disease (CD). However, results on the association between the polymorphisms in TNF-alpha promoter and the risk of CD are inconsistent.
  
  
  OBJECTIVE
  To perform a quantitative synthesis for the genetic polymorphisms in TNF-alpha promoter and CD risk.
  
  
  METHODS
  Databases were searched (up to 2009) and 31 studies were included. Risks of CD associated with the polymorphisms in TNF-alpha promoter were assessed.
  
  
  RESULTS
  Overall, individuals with -1031 TC+CC genotype had a slightly increased risk to develop CD compared with individuals with -1031 TT genotype (OR, 1.32; 95% CI, 1.03-1.70). In the further stratified analysis, we found Asians with the -1031T>C, -863 C>A and -857 C>T variant polymorphisms have almost one and a half CD risk compared with other genotypes (OR, 1.58; 95% CI, 1.16-2.15; OR, 1.55; 95% CI, 1.18-2.02; OR, 1.54; 95% CI, 1.19-1.99 respectively). We did not find -308 G>A variant associated with CD location and disease behaviours in stratified analysis.
  
  
  CONCLUSIONS
  TNF-alpha polymorphisms in the promoter region might be used as a biomarker for CD risk prediction. Larger studies with mixed ethnicity subjects and stratified by clinical and sub clinical characteristics are needed to validate our findings.
authors.affiliation: Xijing Hospital of Digestive Diseases, State Key Library of Cancer Biology, Fourth Military Medical University, Xi'an, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Han
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Han
authors.forename: Y
authors.initials: Y
authors.lastname: Han
authors.forename: J
authors.initials: J
authors.lastname: Qiu
authors.forename: Y
authors.initials: Y
authors.lastname: Shi
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: A
authors.initials: A
authors.lastname: Sun
authors.forename: J
authors.initials: J
authors.lastname: Ding
authors.forename: K
authors.initials: K
authors.lastname: Wu
authors.forename: D
authors.initials: D
authors.lastname: Fan
mesh_terms: D003424:Crohn Disease / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D009336:Necrosis / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012307:Risk Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha