[Influence of H. pylori infection on upper gastrointestinal damage]

H. pylori infection and low-dose aspirin (LDA) are not only independent causal factors of peptic ulcer and gastrointestinal bleeding, they also have synergistic and additive effects. H. pylori infection rate has drastically decreased over the past decade to 34.3% amongst people in their 40's, 28.0% amongst those in their 30's, and 15.7% amongst those in their 20's. Therefore, LDA are expected to become more important factor of peptic ulcer in the near future. The incidence of peptic ulcer induced by LDA was 15.8% (16/101) in authors' hospital. Deep ulcers(more than proper muscularis layer) were only 4 cases, shallow ulcers(submucosal layer) were 12 cases. All deep ulcers were gastric ulcers (3 H. pylori positive, 1 negative), on the other hand shallow ulcers were 8 gastric ulcers (3 H. pylori positive, 5 negative), and 4 duodenal ulcers (1 H. pylori positive, 3 negative). Majority of peptic ulcers induced by LDA were shallow, and independent on H. pylori infection.