[Two necessary strategies of gastric cancer prevention from the point of epidemiologic view].

H. pylori infection mainly occurs under five years of age, interruption of which may be an effective preventive strategy against gastric cancer. Infection to children can be interrupted if H. pylori harbored by persons around the children was eradicated. Prevention of gastric cancer death of adults with H. pylori infection may be another strategy. Risk evaluation of gastric cancer for each subject is inevitable because current Japanese population is a mixture of infected high risk subjects and low risk ones. Combined use of serum pepsinogens and H. pylori antibody test is a useful method of the risk evaluation. According to the evaluation, some subjects should undergo H. pylori eradication therapy and/or periodical examination, which may prevent gastric cancer deaths effectively.