What is the most common cause of chronic gastritis?

Most Common Cause of Chronic Gastritis

Helicobacter pylori infection is the most common cause of chronic gastritis worldwide. 1, 2

Epidemiology and Pathogenesis

H. pylori infection is the world's most common chronic infection in humans, with the following characteristics:

• It is the dominant etiology of atrophic gastritis, which affects up to 15% of the US population 1
• The rate ratio of atrophic gastritis in patients with vs. without H. pylori infection is 5.0 (95% CI, 3.1-8.3) 1
• The infection is typically acquired in childhood, especially via transmission within families 1
• Among those with H. pylori infection, the lifetime risk of peptic ulcer is approximately 17% 1, 2
• H. pylori is strongly urease positive, which is a key diagnostic feature 2

Other Causes of Chronic Gastritis

While H. pylori is the predominant cause, other etiologies include:

1. Autoimmune gastritis (AIG):

   • Significantly less common than H. pylori-associated gastritis
   • Prevalence estimated at 0.5-2% of the population 1
   • More common in women and increases with age
   • Often associated with other autoimmune diseases (especially thyroid disorders) 1, 2

2. Other rare causes:

   • Chronic inflammatory conditions such as Crohn's disease 3
   • Lymphocytic or collagenous gastroenteropathies 3
   • Environmental factors: tobacco use, high-salt diet, and possibly chronic bile acid reflux 1

Clinical Significance and Complications

Chronic gastritis caused by H. pylori has significant clinical implications:

• It is the first step in a multistep precancerous cascade that can lead to intestinal metaplasia, dysplasia, and ultimately gastric adenocarcinoma 1
• The risk of progression from atrophic gastritis to gastric adenocarcinoma ranges from 0.1% to 0.3% per year 1
• H. pylori eradication prevents ulcer recurrences and development of new cases of peptic ulcer disease 1
• Severe atrophic gastritis and acid-free stomach are the highest independent risk conditions for gastric cancer 4
• Chronic gastritis can lead to failures in absorption of essential vitamins and micronutrients 4

Diagnostic Approach

For suspected chronic gastritis, the following diagnostic approach is recommended:

1. Endoscopic evaluation with biopsies:

   • Obtain biopsies from both body and antrum/incisura in separate containers 2
   • Look for endoscopic features such as pale mucosa, increased visibility of vasculature, and loss of gastric folds 1, 2

2. Testing for H. pylori:

   • Non-invasive: Urea breath test or stool antigen test 2
   • Invasive: Histology with special stains (e.g., modified Giemsa) 2
   • Stop PPIs for 2 weeks before testing to avoid false negatives 2

3. For suspected autoimmune gastritis:

   • Check antiparietal cell antibodies and anti-intrinsic factor antibodies 1, 2
   • Evaluate for vitamin B-12 and iron deficiencies 2

Treatment Implications

The recognition of H. pylori as the primary cause of chronic gastritis has transformed treatment approaches:

• Eradication therapy should include bismuth-containing quadruple therapy or triple therapy with amoxicillin, clarithromycin, and a PPI for 14 days 2
• In areas with high clarithromycin resistance (≥15%), bismuth-containing quadruple therapy is preferred 2
• Confirm eradication with UBT or stool antigen test at least 4 weeks after completing therapy 2
• Successful eradication of H. pylori has changed peptic ulcer from a chronic disease to a one-off condition 1

Understanding that H. pylori is the most common cause of chronic gastritis is crucial for appropriate diagnosis, treatment, and prevention of serious complications including gastric cancer and peptic ulcer disease.