Seroprevalence of Helicobacter pylori, incidence of gastric cancer, and peptic ulcer-associated hospitalizations in a Canadian Indian population

The living conditions of many aboriginal communities in Canada may place th eir residents at risk for Ii pylori infection. Our aims were to determine: (1) the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance of H. pylori infection in this population, and (3) i f H. pylori could be identified by polymerase chain reaction from the local water. A demographic questionnaire was administered, and blood was collect ed from subjects in an Indian community in northwestern Manitoba. The serum was analyzed by ELISA for IgG to H, pylori and to CagA. ABO and Lewis anti gens were tested. Age-adjusted incidence of gastric cancer and of hospitali zations associated with diagnoses of peptic ulcer were determined for the I ndian and non-Indian Manitoba population in the years 1989-1993. Nested PCR was performed on lake water using H. pylori-specific primers and the ampli cons probed with an internal Dig-labeled probe. Three hundred six (59%) of approximately 518 individuals who were resident in the community at the tim e of the study were enrolled. The ELISA for H. pylori was positive in 291 ( 95%). There was no association between H. pylori seropositivity and age, se x, gastrointestinal complaints, medications, housing characteristics, and A BO or Lewis antigen status. CagA was positive in 84.5% of infected subjects . The average annual age-adjusted incidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higher for treaty-st atus Indians (394.3/100,000) than for non-Indians (203.8/100,000), but gast ric cancer rates were similar (11.2/100,000 vs 11.6/ 100,000). No H. pylori DNA was detected in the lake water. In conclusion, the seroprevalence of C agA-positive H. pylori is high in this representative Manitoban Indian comm unity, This may be associated with an increased risk for peptic ulcer disea se but is not associated with an increased risk for gastric cancer.