Gastritis is extremely common. In 2021, roughly 38.3 million people worldwide were living with a diagnosis of gastritis or duodenitis (inflammation of the upper small intestine, which is often grouped together in tracking data). That translates to about 454 cases per 100,000 people globally. In the United States specifically, atrophic gastritis alone affects an estimated 15% of the population, and milder forms of stomach lining inflammation are even more widespread.
Those numbers only capture cases that get diagnosed. Because gastritis often causes no obvious symptoms, the true prevalence is almost certainly higher.
Global Prevalence by Region
Gastritis rates vary dramatically depending on where you live. East Asia has the highest burden, with about 722 cases per 100,000 people. Andean Latin America is close behind at 705 per 100,000, and Southern Sub-Saharan Africa follows at roughly 604 per 100,000. These regions share higher rates of the bacterial infection that drives most gastritis cases.
On the other end, high-income Asia Pacific countries (Japan, South Korea, Singapore) report the lowest rates at about 127 per 100,000, likely reflecting decades of aggressive screening and treatment programs. Central Asia and the North Africa/Middle East region also sit relatively low, around 210 per 100,000.
There is some good news in the trend lines. The global rate dropped about 13% between 1990 and 2021. That decline tracks closely with falling infection rates of the bacterium responsible for most cases. Still, lower-income countries carry a disproportionate burden, with disability rates more than three times higher than in wealthier nations.
What Causes Most Cases
The single biggest driver of gastritis worldwide is infection with Helicobacter pylori, a spiral-shaped bacterium that burrows into the stomach lining. About 44% of adults globally carry this infection, down from roughly 53% before 1990. That 16% decline over three decades mirrors the falling gastritis rates, but the bacterium remains stubbornly common. In children and adolescents, prevalence still sits around 35% and hasn’t dropped significantly.
Most people pick up H. pylori in childhood through contaminated water or close household contact. In many cases it causes a low-grade inflammation that persists for years or even decades without producing noticeable symptoms. Left untreated, it can progress to more serious forms of gastritis over time.
Painkillers and Other Medications
The second most common cause is regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, and aspirin. These medications work by blocking a protective enzyme in the stomach lining, leaving it vulnerable to acid damage. Endoscopic studies show that 20% to 30% of people who take NSAIDs regularly develop ulcers in the stomach or upper intestine. Even among those who don’t develop full ulcers, visible mucosal damage appears in up to 40% of chronic users. About 2% to 4% of people taking NSAIDs for a year experience serious complications like bleeding or perforation.
Autoimmune Gastritis
A smaller but significant subset of gastritis is autoimmune, where the body’s immune system mistakenly attacks the cells in the stomach lining that produce acid. The global prevalence of autoimmune gastritis is estimated at 3.85%. Rates vary by continent: Africa and Australia report the highest prevalence (around 8%), Europe sits near 5%, and Asia and the Americas are lower at 2% to 3%. This form is particularly important to catch because it can lead to vitamin B12 deficiency, pernicious anemia, and a modestly elevated risk of stomach cancer.
Who Gets Gastritis Most Often
Age is the strongest predictor. Gastritis becomes progressively more common with each decade of life, partly because H. pylori infections have more time to cause cumulative damage, partly because older adults use more NSAIDs for joint pain and heart protection, and partly because the stomach lining naturally thins over time. By age 60, a significant proportion of people have at least some degree of chronic stomach inflammation, whether or not they feel it.
Research into gender differences has focused more on the biological mechanisms than on raw prevalence numbers. Studies of stomach bacteria show that women with healthy stomachs have higher bacterial abundance but lower microbial diversity compared to men. When autoimmune atrophic gastritis develops, it seems to disrupt the gut microbiome more severely in men, reducing their bacterial diversity to a greater degree. Autoimmune gastritis in particular is diagnosed more frequently in women, consistent with the general pattern of autoimmune diseases skewing female.
Many Cases Go Undetected
One reason gastritis statistics likely undercount the real burden is that many people with inflamed stomach linings have no symptoms at all. Chronic gastritis, especially in its earlier stages, can be completely silent. It’s frequently discovered incidentally during endoscopies performed for other reasons. Someone being evaluated for acid reflux, unexplained anemia, or even a routine cancer screening may learn for the first time that their stomach lining shows signs of long-standing inflammation.
When symptoms do appear, they tend to be vague: a gnawing or burning ache in the upper abdomen, nausea, bloating, or feeling full after eating only a small amount. These overlap with dozens of other digestive conditions, which means gastritis is both underdiagnosed in people who have no symptoms and sometimes overdiagnosed based on symptoms alone without confirmation through a biopsy.
Long-Term Risks of Chronic Gastritis
For most people, gastritis is manageable and not dangerous. But chronic atrophic gastritis, the form where the stomach lining gradually loses its acid-producing glands, does carry a real, measurable cancer risk. A retrospective study of 929 patients with chronic atrophic gastritis found that 1.5% progressed to stomach cancer over a median follow-up of about four and a half years. The annual incidence of gastric cancer in this group ranges from 0.1% to 0.3% per year, depending on the study.
Those numbers are low enough that most people with chronic gastritis will never develop cancer, but high enough that doctors recommend periodic monitoring for patients with confirmed atrophic changes. The progression typically happens slowly. Most cancers in the study appeared after three or more years of follow-up, and a larger group (about 8%) first developed precancerous cellular changes that could be caught and managed before becoming malignant.
The risk is highest when chronic gastritis is combined with other factors: ongoing H. pylori infection, smoking, a family history of stomach cancer, or the presence of a specific type of cellular change called intestinal metaplasia. Treating the underlying cause, particularly eradicating H. pylori, substantially reduces progression risk.
Why Rates Are Falling but Still High
The 13% global decline in gastritis rates since 1990 is largely a story about sanitation, antibiotics, and economic development. As clean water access improves and living conditions become less crowded, fewer children acquire H. pylori. When infections are detected, standard antibiotic treatment clears the bacterium in most cases, allowing the stomach lining to heal.
But progress is uneven. In low-income regions, H. pylori infection remains widespread, antibiotic resistance is growing, and access to endoscopy for diagnosis is limited. Meanwhile, in wealthier countries where H. pylori rates have dropped, NSAID use and autoimmune causes are becoming a proportionally larger share of gastritis cases. The condition isn’t going away. It’s shifting in character depending on where you live and what’s driving it.