85 Association of serum antibodies to the helicobacter pylori caga antigen with precancerous gastric lesions in chinese populations with contrasting gastric cancer rates

Abstract PURPOSE: To assess whether serologic markers of Helicobacter pylori infection can account for the differences in prevalence of advanced precancerous gastric lesions (APGL) between two rural Chinese villages. METHODS: We studied asymptomatic adult subjects in Bei Duan village (N = 196) in Linqu County (a high-risk area for gastric cancer) and in Shi Huang village (N = 192) in Cangshan County (a low-risk area for gastric cancer) in Shandong Province, China. Prevalence of APGL was assessed by microscopic examination of endoscopic stomach biopsies. Enzyme-linked immunosorbent assays (ELISA) were used to detect IgG to the H. pylori whole-cell antigen, and to the CagA protein. A logistic regression model was used to quantify the role of the two H. pylori seromarkers in explaining the differences in prevalence of APGL between the two villages, after adjusting for age and sex. RESULTS: The prevalence of APGL was much greater in Bei Duan than in Shi Huang. Although H. pylori seroprevalence by the whole-cell ELISA was similar in the two populations, seroprevalence of CagA was significantly greater in Bei Duan. Although age, sex, and both H. pylori seromarkers were associated with APGL in the logistic regression model, the effect of village of residence remained strong after adjustment for all four covariates. CONCLUSION: Only a relatively small proportion of the variation in prevalence of APGL in the rural Chinese population can be explained by differences in H. pylori seroprevalence, or by differences in CagA seroprevalence.