Helicobacter pylori Infection and Gastric Cancer (A Nested Case-Control Study in a Rural Area of Japan)

We conducted a seroepidemiological nested case-control study to determine the association of gastriccancer with Helicobacter pylori infection and atrophicgastritis. A cohort of 2858 participants in an annual multiphasic health check-up werefollowed for eight years. Data for 45 gastric cancercases and 225 sex-, age-, and address-matched controlsubjects were analyzed. Helicobacter pylori infectionwas determined by IgG antibodies, and atrophicgastritis was diagnosed by both serum pepsinogen I level(≤70 ng/ml) and the pepsinogen I/II ratio (≤3.0).Univariate analysis showed that Helicobacter pylori and atrophic gastritis were significantlyassociated with gastric cancer. In a multivariateanalysis, atrophic gastritis was associated withsignificantly increased risk of cancer (odds ratio,3.38; 95% confidence interval, 1.54-7.42); however,Helicobacter pylori was not associated with cancer (oddsratio, 1.84; 95% confidence interval, 0.59-5.72). Theseresults suggest that Helicobacter pylori infection alone is not directly associated with gastriccarcinogenesis but has an indirect relation to gastriccancer through the development of atrophicgastritis.