title: Helicobacter pylori infection and the risk of gastric malignancy.
abstract: OBJECTIVE
  This prospective cohort study investigated the impact of Helicobacter pylori infection on the development of various gastric malignancies.
  
  
  METHODS
  We prospectively followed up 1,225 dyspeptic Taiwanese who had nonulcer dyspepsia, gastric ulcers, or duodenal ulcers at enrollment. Among them, 618 (50.4%) had H. pylori infection and 607 (49.6%) did not. Patients underwent endoscopy at enrollment and at 1- to 3-yr intervals thereafter.
  
  
  RESULTS
  During a mean follow-up of 6.3 yr, gastric adenocarcinoma developed in 7 of the 618 H. pylori-infected patients, but in none of the 607 uninfected patients (1.1%vs 0.0%, P= 0.015). The incidence of gastric lymphoma was 0.2% (1/618) and 0% in H. pylori-infected and uninfected patients. Taken together, the development rate of gastric malignancy in H. pylori-infected patients was significantly higher than that in uninfected patients (1.3%vs 0%, P= 0.007). Among H. pylori-infected subjects, the incidence of gastric malignancy was similar between those receiving and not receiving eradication therapy (1.4%vs 1.2%). Multivariate analysis showed that intestinal metaplasia was the only independent factor predicting subsequent development of gastric malignancy in H. pylori-infected subjects with an odds ratio of 4.5 (95% CI 1.1-19.1).
  
  
  CONCLUSIONS
  In this prospective cohort study, all gastric malignancies, including adenocarcinoma and lymphoma, developed in H. pylori-infected patients. The finding implies that H. pylori is a necessary cause of most gastric malignancies. Follow-up for H. pylori-infected patients who have intestinal metaplasia is indicated.
authors.affiliation: Division of Gastroenterology and General Medicine, Department of Medicine, Kaohsiung Veterans General Hospital and National Yang-Ming University, Kaohsiung, Taiwan.
authors.forename: Ping-I
authors.initials: PI
authors.lastname: Hsu
authors.forename: Kwok-Hung
authors.initials: KH
authors.lastname: Lai
authors.forename: Ping-Ning
authors.initials: PN
authors.lastname: Hsu
authors.forename: Gin-Ho
authors.initials: GH
authors.lastname: Lo
authors.forename: Hsien-Chung
authors.initials: HC
authors.lastname: Yu
authors.forename: Wen-Chi
authors.initials: WC
authors.lastname: Chen
authors.forename: Feng-Woei
authors.initials: FW
authors.lastname: Tsay
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Lin
authors.forename: Hui-Hwa
authors.initials: HH
authors.lastname: Tseng
authors.forename: Luo-Ping
authors.initials: LP
authors.lastname: Ger
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Chen
mesh_terms: D000230:Adenocarcinoma / Q000382:microbiology*; D016009:Chi-Square Distribution; D016099:Endoscopy, Gastrointestinal; D005260:Female; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000382:microbiology*; D013624:Taiwan