title: Helicobacter pylori infection may be implicated in the topography and geographic variation of upper gastrointestinal cancers in the Taihang Mountain high-risk region in northern China.
abstract: BACKGROUND
  Helicobacter pylori infection is prevalent in China. Chronic infection of the bacterial not only causes distal stomach cancer, but also confers risk to gastric cardia adenocarcinoma. Because H. pylori infection is inversely associated with esophageal adenocarcinoma, globally the infection rate is significantly correlated with the ratio of squamous carcinoma to adenocarcinoma of the esophagus. These agree with the topography of upper gastrointestinal cancer observed in the Taihang Mountain high-risk region where both gastric cardia and non-cardia adenocarcinoma coincide with esophageal squamous cancer, but with almost no distal esophageal adenocarcinoma. Moreover, as altitude increases from plain to mountains, we observed progressively increasing incidence rates of gastric adenocarcinomas in recent years in the region. Because H. pylori infection is a definite carcinogen to gastric adenocarcinoma and is more prevalent in the mountain than in plain areas due to undeveloped living conditions, the observation gives the impression as though H. pylori infection is implicated.
  
  
  OBJECTIVE
  This article aims to note the role of H. pylori infection in upper gastrointestinal cancer in the Taihang Mountain high-risk region in northern China.
  
  
  METHODS
  First the unique topography and geographic variation of upper gastrointestinal cancer in the region is described to indicate a possible role of H. pylori infection, then we review studies on prevalence of H. pylori infection in the high-risk region and describe difference in socioeconomic development and water hygiene between the plains and the mountains as related to the prevalence of H. pylori infection.
  
  
  RESULTS
  Coincidence of gastric cancer in the region and a progressively increasing rate of the cancer from the plain towards the mountains indicate H. pylori infection may be implicated in upper gastrointestinal cancer.
  
  
  CONCLUSIONS
  International collaboration is needed to study H. pylori and upper gastrointestinal cancer in the region when rapid industrialization is just beginning.
authors.affiliation: Department of Epidemiology, 4th Hospital of Hebei Medical University, Shijiazhuang, China.
authors.forename: Denggui
authors.initials: D
authors.lastname: Wen
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.forename: Baoen
authors.initials: B
authors.lastname: Shan
authors.forename: Shijie
authors.initials: S
authors.lastname: Wang
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology* / Q000382:microbiology* / Q000473:pathology; D005843:Geography; D016481:Helicobacter Infections / Q000150:complications* / Q000453:epidemiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged