title: Helicobacter species infection may be associated with cholangiocarcinoma: a meta-analysis.
abstract: OBJECTIVE
  Since the discovery of Helicobacter species in human biliary system, the association between Helicobacter species infection and cholangiocarcinoma is under debate. This meta-analysis aims to explore this issue.
  
  
  METHODS
  Literature search was carried out to identify all eligible articles. We performed overall meta-analysis of all included studies and subgroup analysis based on regional distribution. Subgroup analysis in the light of detection methods and specimens was also conducted.
  
  
  RESULTS
  Ten case-control studies were included. Overall meta-analysis favoured a significant association between Helicobacter species infection and cholangiocarcinoma (cumulative OR 8.88, 95% CI 3.67-21.49). Subgroup analysis based on geographic distribution indicated that Helicobacter species infection may serve as a risk factor not only in a region with high cholangiocarcinoma incidence (Asia, OR 6.68, 95% CI 2.29-19.49) but also in low incidence region (Europe, OR 14.90, 95% CI 4.79-46.35). The other subgroup analysis showed that PCR was the most effective and efficient method to detect Helicobacter species in surgically resected tissue and bile. There was significant heterogeneity among studies and obvious publication bias.
  
  
  CONCLUSIONS
  Our meta-analysis supports the possible association between Helicobacter species infection and cholangiocarcinoma. Further investigations are required to clarify the role of Helicobacter species in this malignancy.
authors.affiliation: Department of Hepatobiliary Surgery II, Southern Medical University Zhujiang Hospital, Guangzhou, Guangdong Province, China; Department of Hepatobiliary Surgery, Wuxi People's Hospital of Nanjing Medical University, Wuxi, Jiangsu Province, China.
authors.forename: M
authors.initials: M
authors.lastname: Xiao
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001650:Bile Duct Neoplasms / Q000382:microbiology*; D001653:Bile Ducts, Intrahepatic / Q000382:microbiology*; D018281:Cholangiocarcinoma / Q000382:microbiology*; D004812:Epidemiologic Methods; D016998:Helicobacter / Q000302:isolation & purification; D016481:Helicobacter Infections / Q000150:complications*; D006801:Humans