Relative risk of gastric cancer between those with and without infection history in Japan.

Background And Aim: The causal relationship between () infection and gastric cancer has been established. Although the magnitude of the carcinogenic effect of is the next concern, it has not been sufficiently evaluated in Japan. Spontaneous disappearance of infection may have provoked underestimation of the carcinogenic effect of the infection. To reduce the influence, a comparison should be carried out between subjects with and without the infection history. Cutoff values of antibody lower than the manufacturer's recommendation are known to be more appropriate to diagnose history of infection. The aim was to evaluate the carcinogenic effect of .

Methods: A case-control study consisting of 275 gastric cancer patients and 275 age- and sex-matched controls was performed. Serum antibody was measured using the "JHM-Cap" kit with a domestic antigen (cut value of the manufacturer's recommendation was 2.3 EV: ELISA value). Using a conditional logistic model, the odds ratios (ORs) for five cutoff values adjusted for smoking and drinking doses were calculated.

Results: For cutoff values of 1.25, 1.5, 1.75, 2.0, and 2.3 EV, the ORs (95% confidence intervals) were 67.7 (9.1, 502), 37.2 (8.8, 157), 21.3 (9.0, 60.2), 25.5 (9.0, 72.7), and 25.9 (9.2, 73.2), respectively.

Conclusions: These results suggest that the risk ratio of gastric cancer between subjects with and without history of infection in Japan may exceed 20.