The aim of this study was to choose the factors related to biomarkers of gastric cancer, and to help establish more effective screening of gastric cancer. Health checkups were performed for residents of four countries; Japan, Dominican Republic, Tanzania, and China. The checkups consisted of questionnaires and testing of biomarkers of gastric cancer; the former including the property of subjects, investigated country, sex, age, educational status, etc., and life style, dietary habits, smoking habits, alcohol consumption, their living environment, past history for upper digestive disease, and subjective symptoms related to them whereas the latter included biomarkers of gastric cancer, serum pepsinogenes, serum gastrin, and antibody to Helicobacter pylori. Data of the questionnaire and testing of biomarkers of gastric cancer were analyzed by univariate and multivariate analysis.
Health checkups in Tanzania were performed among residents living in 2 counties, Kivaha and Hai, after getting
approval of our research by the ethical committee for medical research in Tanzania on January and February in 2001. Volunteer subjects were collected from inhabitants living in two counties, which consisted of a total of 573 people ; 245 and 328 subjects were for male and female, respectively. On the other hands, health checkups in Dominican Republic were performed using a similar protocol as the research in Tanzania from November in 2001 to March in 2002. After having been approved by the ethical committee for medical research in the center of the friendship relations between Japan and Dominican Republic for medical education, volunteers in three cities cooperated in this research which consisted of 451 male and 764 female subjects; total 1215 subjects. Further, data of health checkups in Japan and China were analyzed with data in the abovementioned two countries. The number of subjects for male, female, and total were 323 & 536, 648 & 1093, 859 & 1741 people of general population in Japan and China, respectively. Data of the biomarkers of gastric cancer were analyzed among these four countries epidemiologically.
As population composition among four countries were much different, prevalence of chronic atrophic gastritis and infectious rate to Helicobacter pylori were compared among four countries after adjusting our investigated subjects to their populations and taking world population in 1995 as standard population. Prevalences of chronic atrophic gastritis were defined by serum pepsinogens, PG I <__= 70 (ug/1) & PG I / PG II <__= 3, which were 0.492, 0.117, 0.319, and 0.202 in Japan, China, Tanzania, and Dominican Republic, respectively, and which were much different among these four countries.
And then, logistic regression analysis was done in order to choose factors related to chronic atrophic gastritis which was considered as the precursor lesion gastric cancer. Still, variables were taken chronic atrophic gastritis as dependent one and investigated country, sex, age, subjective symptoms and past history related to upper digestive tract, smoking habits, alcohol consumption, serum gastrin level and infection to HP were chosen as significant variables, which were related to chronic atrophic gastritis. Odds ratio for chronic atrophic gastritis were 0.14, 0.62, and 0.38 times in China, Tanzania, and Dominican Republic, respectively, compared with risks in Japan. The risk for CAG was reduced in the three countries compared with risk in Japan. Conversely, as subjects got one year older than as serum gastrin level of them increased by 1 pg/ml, the risk to CAG increased by 1.3 and 0.6 percent, respectively. Besides, HP infection factor increased the risk of prevalence of CAG to the same extent as age and serum gastrin level factors. The risk was 5.3 times as much in CAG subjects compared with subjects without HP infection. Less