title: Association between Helicobacter pylori infection and colorectal neoplasm risk: a meta-analysis based on East Asian population.
abstract: OBJECTIVE
  The association between Helicobacter pylori (HP) infection and colorectal neoplasm risk was not clear. The aim of this study was to evaluate whether HP infection can increase the risk of developing colorectal neoplasm by meta-analysis.
  
  
  METHODS
  A detailed literature search was performed on Medline, PubMed, Web of Science, and China National Knowledge Infrastructure for related research publications written in English and/or Chinese. The relevant case-control or cohort studies reporting an association between HP infection and colorectal neoplasm risk were screened and included in this meta-analysis. The association between HP infection and colorectal neoplasm risk was expressed by odds ratio (OR) and its 95% confidence interval (CI). The heterogeneity among the included articles was assessed by I 2 test, and the pooled OR was calculated by fixed effect model in case of no significant heterogeneity otherwise random effect model was employed. All the statistical analyses were done by STATA-11.0 and MetaAnalyst Beta 3.13 software.
  
  
  RESULTS
  Finally, a total of 2081 colorectal neoplasm patients and 5598 healthy controls from nine eligible studies were included in this meta-analysis. The pooled OR for the association between HP infection and colorectal neoplasm risk was 0.18 with its 95% CI of 0.99-1.40, (P > 0.05). We further divided the colorectal neoplasm into the hyperplastic polyps, adenomas and colorectal cancer sub-groups according to colorectal neoplasm types. The pooled ORs and their 95% CIs were OR Hyperplastic_polyps = 0.72, 95% CI: 0.44-1.18, (P > 0.05), OR Adenomas = 1.83, 95% CI: 1.35-2.51, (P < 0.01), OR Colorectal_cancer = 1.08, 95% CI: 0.89-1.68 (P > 0.05). For different region sub-groups, the pooled ORs and 95% CIs were OR South_Korea = 1.18, 95% CI: 0.84-1.66, (P > 0.05), OR China = 0.78, 95% CI: 0.53-1.13, (P > 0.05), OR Taiwan = 1.06, 95% CI: 0.69-1.62, (P > 0.05), OR Japan = 1.33, 95% CI: 1.07-1.65, (P < 0.05) for South Korea, China main land, Taiwan and Japanese.
  
  
  CONCLUSIONS
  In general, no statistical association between HP infection and colorectal neoplasm risk was found in this meta-analysis. But, HP infection may increase the risk of developing colorectal adenomas.
authors.affiliation: Department of Clinical Laboratory, Peking University People's Hospital, 100044 Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Guo
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Li
mesh_terms: D015179:Colorectal Neoplasms / Q000382:microbiology*; D016481:Helicobacter Infections / Q000150:complications* / Q000453:epidemiology*; D016480:Helicobacter pylori; D006801:Humans; D012307:Risk Factors