Helicobacter pylori and Gastritis Association

H. pylori is the most important factor in the pathogenesis of chronic gastritis, present in 71-95% of all gastric cancer cases. 1, 2

Types of Gastritis Associated with H. pylori

H. pylori is the primary bacterial cause of gastritis, recognized as the most important factor in the pathogenesis of chronic gastritis 1
H. pylori infection causes two main patterns of gastritis:
- Antral-predominant gastritis - leads to increased acid production 1, 2
- Corpus-predominant gastritis - causes decreased acid production and substantially increases gastric cancer risk 1, 2
Pangastritis (involving both antrum and corpus) is the most common type (71.2% of cases) associated with H. pylori infection 3
Antral gastritis is the second most common type (28.8% of cases) associated with H. pylori 3

H. pylori causes persistent active gastritis that may progress through a cascade: chronic active gastritis → atrophic gastritis → intestinal metaplasia → gastric cancer 1, 2
The infection increases gastric cancer risk by approximately 2.5-fold, with some studies showing up to 6-fold increased risk 4, 2
Atrophic corpus gastritis caused by H. pylori leads to hypochlorhydria 5
Hypochlorhydria allows overgrowth of non-H. pylori organisms capable of producing carcinogenic metabolites 5
H. pylori infection reduces luminal concentrations of ascorbic acid, an antioxidant that scavenges carcinogenic N-nitrosamines and reactive oxygen species 5

Gastric cancer is rare in the absence of chronic active gastritis 5
The extent and severity of gastritis, along with atrophy and intestinal metaplasia, are positively associated with cancer risk 5
The lifetime risk of peptic ulcer disease is approximately 17% in those infected with H. pylori 1
The risk of progression from atrophic gastritis to gastric adenocarcinoma ranges from 0.1% to 0.3% per year 1, 2

H. pylori infection can be diagnosed through non-invasive tests such as urea breath test and monoclonal stool antigen tests 1, 2
Endoscopy with biopsy allows for histological examination to identify both H. pylori and the pattern/severity of gastritis 1
False positive urea breath test results can occur in patients with achlorhydria due to overgrowth of non-H. pylori urease-producing organisms 1

Eradication of H. pylori is recommended whenever it is diagnosed, as it is recognized as an infectious disease with significant risk to the host 1
H. pylori eradication results in disappearance of both acute and chronic gastritis, supporting its causal role in gastritis pathogenesis 6
Eradication of H. pylori before the development of preneoplastic conditions is most effective in reducing gastric cancer risk 5, 1
H. pylori treatment may improve atrophic gastritis, but intestinal metaplasia is generally considered irreversible 5, 7
Eradication of H. pylori is the most promising strategy to reduce gastric cancer incidence 4

Autoimmune gastritis is the third major cause of gastritis, though significantly less common than H. pylori-associated gastritis 2
Autoimmune gastritis has an estimated prevalence of 0.5-2% compared to up to 15% for all forms of atrophic gastritis 2
Hereditary diffuse gastric cancer (less than 1% of gastric carcinomas) is not related to H. pylori infection or gastritis 5