Seroprevalence of Helicobacter pylori, Incidence of Gastric Cancer, and Peptic Ulcer-Associated Hospitalizations in a Canadian Indian Population

The living conditions of many aboriginalcommunities in Canada may place their residents at riskfor H. pylori infection. Our aims were to determine: (1)the seroprevalence of H. pylori in a traditional Indian community, (2) the clinical relevance ofH. pylori infection in this population, and (3) if H.pylori could be identified by polymerase chain reactionfrom the local water. A demographic questionnaire was administered, and blood was collected fromsubjects in an Indian community in northwesternManitoba. The serum was analyzed by ELISA for IgG to H.pylori and to CagA. ABO and Lewis antigens were tested. Age-adjusted incidence of gastric cancer and ofhospitalizations associated with diagnoses of pepticulcer were determined for the Indian and non-IndianManitoba population in the years 1989-1993. Nested PCR was performed on lake water using H.pylori-specific primers and the amplicons probed with aninternal Dig-labeled probe. Three hundred six (59%) ofapproximately 518 individuals who were resident in the community at the time of the study wereenrolled. The ELISA for H. pylori was positive in 291(95%). There was no association between H. pyloriseropositivity and age, sex, gastrointestinalcomplaints, medications, housing characteristics, and ABOor Lewis antigen status. CagA was positive in 84.5% ofinfected subjects. The average annual age-adjustedincidence of hospitalizations associated with diagnoses of peptic ulcer disease in Manitoba was higherfor treaty-status Indians (394.3/100,000) than fornon-Indians (203.8/100,000), but gastric cancer rateswere similar (11.2/100,000 vs 11.6/ 100,000). No H. pylori DNA was detected in the lake water. Inconclusion, the seroprevalence of CagA-positive H.pylori is high in this representative Manitoban Indiancommunity. This may be associated with an increased risk for peptic ulcer disease but is notassociated with an increased risk for gastriccancer.