title: Helicobacter pylori infection and oesophageal cancer risk: association studies via evidence-based meta-analyses.
abstract: OBJECTIVE
  Infection of Helicobacter pylori, a major cause of various gastric diseases, has been reported to play a role in the process of tumorigenesis and progression of gastric carcinoma. Some studies have been devoted to the relationship between H. pylori infection and oesophageal cancer and have yielded conflicting results. Whether infection of H. pylori is a risk factor for this cancer remains uncertain. In this study we aimed to evaluate the association of H. pylori infection with oesophageal cancer risk.
  
  
  METHODS
  The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications, then the extracted data were further analysed by systematic meta-analyses.
  
  
  RESULTS
  In total, 195 articles were identified, of which 12 case-control studies concerning oesophageal cancer were selected. Oesophageal adenocarcinoma risk for H. pylori infection was 0.58-fold (95% confidence interval 0.48-0.70) (Z=5.79, P<0.01) compared with the controls. Oesophageal squamous cell carcinoma risk was 0.80-fold (95% confidence interval 0.45-1.43) (Z=0.75, P>0.05) compared with the controls. Compared with CagA-negative H. pylori, CagA-positive H. pylori markedly decreased oesophageal cancer risk.
  
  
  CONCLUSIONS
  The pooled data suggest infection of H. pylori as a possible preventive factor for oesophageal adenocarcinoma and failed to suggest a significant association between H. pylori infection and oesophageal squamous cell carcinoma.
authors.affiliation: Department of Otolaryngology, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Xianlu
authors.initials: X
authors.lastname: Zhuo
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Wenlei
authors.initials: W
authors.lastname: Zhuo
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Zhang
mesh_terms: D016022:Case-Control Studies; D016208:Databases, Factual; D004938:Esophageal Neoplasms / Q000209:etiology*; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D006801:Humans; D012306:Risk; D012307:Risk Factors