Risk factors for gastric cancer in Japan in the 2010s: a large, long-term observational study

Background The numbers of Helicobacter pylori (HP)-infected individuals and deaths due to gastric cancer are decreasing in Japan. We aimed to determine whether the serological test for chronic gastritis (the ABC method) is still useful for gastric cancer risk stratification in the 2010s and to analyze risk factors for developing gastric cancer in Japan. Methods In this prospective study, we monitored 20773 individuals for the incidence of gastric cancer from 2010 to 2019. The relationships between blood sampling results, physical examination, and lifestyle in 2010 and the cumulative incidence of gastric cancer were analyzed. Results A total of 19343 participants who met the study criteria were analyzed. Overall, 0.08% of participants in group A (9/11717), 0.63% in group B (28/4452), 2.05% in group C (43/2098), 1.52% in group D (1/66), and 0.30% in group E (3/1010) developed gastric cancer. Cox hazard analysis showed that age ≥ 50 years; groups B, C, and D according to the ABC method; and current smoking habits were independent risk factors for gastric cancer. The hazard ratios (HRs) of the incidence of gastric cancer were 6.7 in group B and 21.7 in groups C and D, while the HRs of group E was 2.8, which was not significantly different from that of group A. The incidence of gastric cancer was not statistically significantly different between those with and without successful HP eradication in groups B, C, and D during follow-up. Conclusions The ABC method was still useful for gastric cancer risk stratification in the 2010s.