Risk Factors for Helicobacter pylori Infection among a Rural Population in Japan: Relation to Living Environment and Medical History.

BACKGROUND: Helicobacter pylori infection is related to several gastroduodenal diseases, though the route of transmission remains unclear. METHODS: A cross-sectional study that included 695 healthy people (males 308, females 387; median age 60 years) participating in a health checkup program in Yamagata Prefecture was conducted. H. pylori status was determined in all subjects by evaluation of serum anti-H. pylori immunoglobulin G antibody. Antibody against hepatitis A virus was used as a marker of fecal-oral exposure to assess the agreement between H. pylori infection and hepatitis A virus infection. Data on other factors known or suspected to be related to infection status were also collected using a questionnaire. RESULTS: Seroprevalence of H. pylori and hepatitis A virus was 60% and 70%, respectively. Kappa values for subjects aged 20-49 and aged 50 or older were 0.07 and 0.02, respectively, and agreement between the presences of both infections was assessed as slight. In the multivariate logistic regression analysis, H. pylori infection was significantly associated with availability of a sewage system in childhood (presence [reference], absence [odds ratio (OR)=4.06, 95% confidence interval (CI): 1.36-13.94]) and the number of gastrointestinal endoscopies undergone (none [reference], once [OR=1.64, 95% CI: 0.83-3.27], 2-3 times [OR=3.11, 95% CI: 1.65-5.99], or 4 or more times [OR=3.18, 95% CI: 1.71-6.03]), (p<0.01 for trend). CONCLUSIONS: Our results suggest that poor hygiene in childhood is related to H. pylori infection. The fecal-oral route does not seem to be an important mode of transmission, but the possibility of transmission by gastrointestinal endoscopic examination exists.