A new report found that Helicobacter pylori, the bacterium best known for causing stomach ulcers, may be associated with one in five cases of bowel cancer worldwide.

Although H. pylori infects nearly half of adults, the authors cautioned that their findings do not prove the bacterium causes bowel cancer. Also known as colorectal cancer, the disease develops in the colon or rectum and affects about 1.9 million people worldwide each year, according to the American Cancer Society.

H. pylori is already known to cause stomach cancer. The National Institutes of Health identifies the bacterium as the leading cause of gastric cancer.

The authors published their findings last week in the journal eGastroenterology. They said the report adds to evidence that eliminating H. pylori infections should be a global public health priority.

Gastric cancer is the third most common cancer worldwide, with H. pylori identified as the major cause, according to the National Institutes of Health.

A 2024 study of U.S. veterans found a small but statistically significant increase in bowel cancer risk among people with untreated, active H. pylori infections.

Other risk factors for bowel cancer include age, genetic predisposition, smoking, obesity and diets high in processed meats such as hot dogs, sausage and bacon.

The authors called for high-quality, long-term studies to determine whether eliminating H. pylori infections could reduce bowel cancer rates.

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