Health
Study Links Stomach Bacterium H. Pylori to Nearly a Quarter of Global Bowel Cancer Cases
By BMJ Group Sep 8 2026 Reviewed
A new exploratory study suggests that exposure to Helicobacter pylori, a bacterium commonly found in the stomach, may be associated with more than one in five bowel cancer cases worldwide. The research, published in the open-access journal eGastroenterology, also indicates that people born in more recent decades could face a higher risk of the disease following exposure to the microbe.
Bowel cancer ranks as the second leading cause of cancer-related death globally. In 2022 alone, there were nearly 2 million new cases and approximately 900,000 deaths attributed to the disease, according to the researchers.
H pylori is already classified as a group 1 carcinogen due to its well-established link to stomach cancer. However, its connection to bowel cancer has remained a subject of ongoing debate despite growing evidence supporting a relationship.
To better understand this potential link and inform prevention strategies, particularly in regions with high H pylori prevalence and limited healthcare resources, researchers analyzed data from systematic reviews and pooled studies. They examined variables such as geographic region, diagnostic methods, sex, availability of national screening programs, and use of antibiotic eradication therapy. Global bowel cancer case estimates were drawn from the Global Cancer Observatory for 2022.
The analysis found that individuals exposed to H pylori had a 1.6-fold higher risk of developing bowel cancer compared to those without exposure. No significant differences emerged when results were broken down by sex, age groups above or below 60, diagnostic approach, or presence of national screening programs.
Among four observational studies examining eradication therapy, treatment to eliminate H pylori was associated with reduced bowel cancer risk, but this benefit only became apparent after a decade.
Combining data from 43 studies covering nearly 48.7 million people, researchers estimated that H pylori exposure could be linked to about 22% of bowel cancer cases globally. When the analysis was narrowed to 14 population-based and cohort studies, this figure dropped to 12%.
Regional variations were notable. The Western Pacific region and Mongolia showed the highest estimated proportions of bowel cancer cases potentially tied to H pylori exposure, at 25% and 36% respectively. China recorded the highest absolute number of linked cases, at 139,619. Interestingly, despite similarly high H pylori prevalence rates in Africa, South-East Asia, and the Eastern Mediterranean, these regions showed comparatively lower proportions of attributable cases.
Further analysis revealed that the proportion of bowel cancers connected to H pylori exposure increased among younger birth cohorts. The estimated proportion rose from 9.5% among those born before 1947, to roughly 10% for those born between 1948 and 1962, and reached 15% for those born between 1963 and 1977.
The study's authors emphasized that numerous other factors influence bowel cancer development, including non-modifiable elements like genetics and age, as well as modifiable lifestyle and dietary factors. Globally, these factors account for a larger share of bowel cancer cases than H pylori exposure does.
The researchers noted that population-level control of H pylori could potentially help prevent both gastric cancer and, if the connection to bowel cancer proves causal, reduce that disease burden in areas with high infection rates. However, they cautioned that the success of such efforts would depend on local disease patterns, healthcare infrastructure, and coordination with existing bowel cancer screening programs.
They also raised concerns similar to those associated with gastric cancer prevention efforts—namely, that widespread antibiotic use for H pylori eradication could raise issues related to antibiotic stewardship, resistance, and treatment side effects.
The study's authors concluded that the findings highlight the need for well-designed randomized clinical trials and other prospective research to further evaluate how H pylori exposure and its treatment affect bowel cancer risk, along with any factors that might modify this relationship.
The research was published as: Li, Y., et al. (2026). "Global and regional burden of colorectal cancer potentially related to Helicobacter pylori exposure: a risk attribution modelling study." eGastroenterology. DOI: 10.1136/egastro-2026-100436.