Helicobacter pylori and stomach cancer: A case-control study in Venezuela

The role of Helicobacter pylori infection in gastric cancer was evaluated i n a high-risk population in Venezuela using serological assays in a study o f 302 cases and 483 neighborhood controls. To investigate the claim that as says for ii. pylori should use antigens derived from local strains, four di fferent assays derived from Venezuelan and European strains were used, Prev alence of IBG II. pylori antibodies in controls was very high, with estimat es between 72 and 92%, Prevalence was similar in cases and controls. Howeve r, cases had lower antibody titers, This effect was observed only in subjec ts with low pepsinogen (PC) levels PGI/PGII <3.0), which suggested that ext ensive atrophy in cases causes a loss of H. pylori infection, with a conseq uent reduction in antibody titer, In addition, advanced cases (stage IT or higher) had lower antibody titers than less advanced cases, which indicated that the lower antibody titers in cases may be attributable partially to a diminished immune response. All of the four assays for anti-II, pylori ant ibodies gave similar results, No evidence was found for the superiority of the assay based on Venezuelan strains. These results are consistent with ot her case-control studies In high-risk populations and highlight the difficu lties of investigating H. pylori infection in retrospective studies.