[Chronological change in gastric acid secretion in Japanese]

The gastric acid secretion level is an important determinant for the manifestation of the gastroesophageal reflux disease spectrum, finally leading to the development of esophageal adenocarcinoma. The overall gastric acid secretion level of Japanese men relatively increased during the last 20 years with a successive decline in the Helicobacter pylori (H. pylori) infection rate, and this trend will continue for several more decades in Japan. However, considering that gastric acid secretion remained unchanged in H. pylori-negative Japanese men over the 20-year period at a level much lower than that in Occidental subjects, upper gastrointestinal disease profiles in the Asian population including Japanese people will still differ from those in Western countries in the post-H. pylori era.