title: Association between Helicobacter pylori infection and the risk of colorectal neoplasia: a systematic review and meta-analysis.
abstract: OBJECTIVE
  The existing evidence on the relationship between Helicobacter pylori infection and the risk of colorectal neoplasia is inconsistent. We conducted a systematic review with a meta-analysis to explore this relationship and to determine whether the relationship varies according to the study characteristics.
  
  
  METHODS
  We searched the PubMed database and the reference lists of pertinent articles published up to July 2012. Summary odds ratios (ORs) with their 95% confidence intervals (CIs) were estimated using a random-effects model.
  
  
  RESULTS
  Twenty-seven studies including 3792 cases of colorectal adenoma (CRA) and 3488 cases of colorectal cancer (CRC) were identified. Overall, H. pylori infection was associated with an increased risk of CRA (OR = 1.66, 95% CI 1.39-1.97, I(2)  = 54.3%) and CRC (OR = 1.39, 95% CI 1.18-1.64, I(2)  = 35.8%), although there was significant heterogeneity among the studies. Subgroup analysis revealed that the positive correlation did not differ by sex, geographic variation or subsite of neoplasia, but might vary by the method of detection of H. pylori. The study was underpowered to determine the risk of colorectal neoplasia associated with cytotoxin-associated gene A-positive H. pylori.
  
  
  CONCLUSIONS
  This meta-analysis demonstrates a positive association between H. pylori infection and the risk of colorectal neoplasia.
authors.affiliation: State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.forename: Z-P
authors.initials: ZP
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Xu
authors.forename: L-C
authors.initials: LC
authors.lastname: Gao
authors.forename: D-M
authors.initials: DM
authors.lastname: Fan
mesh_terms: D000236:Adenoma / Q000453:epidemiology*; D002277:Carcinoma / Q000453:epidemiology*; D003111:Colonic Polyps / Q000453:epidemiology*; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori; D006801:Humans; D016017:Odds Ratio; D012307:Risk Factors
keywords: Helicobacter pylori; colorectal adenoma; colorectal cancer; meta-analysis; systematic review