We clarified the clinical significance of measurement of IgG antibody titers against Helicobacter pylori using data from a nested case-control study from a large-scale cohort study in Japan.Method:
Participants included 36,745 subjects from the Japan Health Center-based Prospective Study who responded to the baseline questionnaire and provided a blood sample. Subjects were aged 40-69 years and were followed over 15 years after initial sampling. Controls were matched to 511 gastric cancer patients. Plasma surface antigen (Hp)-IgG titer was measured using ELISA, and mucosal atrophy was determined by measuring pepsinogen I and II levels.Results:
Seropositive subjects with low Hp-IgG titer and mucosal atrophy showed a higher risk for gastric cancer than high-titer subjects. Odds ratio (OR) referred to cases with true negative IgG titers and no mucosal atrophy. In moderately atrophic subjects, the low titer OR was 19.0, with a 95% confidence interval (CI) of 7.7-46.9, and 12.5 for high titer, with a 95% CI of 5.2-30.0. In severely atrophic subjects, the low titer OR was almost double that of high-titer subjects (OR = 30.2, 95% CI = 12.4-73.7 and OR = 15.9, 95% CI = 6.3-40.3, respectively). These associations were observed more frequently for differentiated than undifferentiated gastric cancer.Conclusion:
Combination assay with Hp-IgG titer and pepsinogens may help identify groups at high risk for gastric cancer. Subjects with low Hp-IgG titer and mucosal atrophy were at extremely high risk for gastric cancer, particularly differentiated cancer. Subjects with this background may require ongoing observation and periodic endoscopic examination for early cancer detection.