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Exploratory analysis finds link between H. pylori exposure and bowel cancer risk, with those born in more recent decades potentially more vulnerable; researchers call for long term trials on eradication therapy
Exposure to Helicobacter pylori (H. pylori), a bacteria that lives in the stomach, may be associated with more than one in five bowel cancer cases worldwide, an exploratory risk attribution study has suggested. The analysis has also indicated that people born in more recent decades could face a greater risk of the disease following exposure, and its authors have concluded that high quality, long term studies are needed to establish whether eradication therapy with antibiotics meaningfully lowers bowel cancer risk.
Bowel cancer is the second leading cause of cancer related death worldwide. In 2022 alone, there were nearly two million novel cases and 900,000 deaths from the disease, the researchers noted.
H. pylori is classified as a group 1 (definite) human carcinogen, given its established causal association with stomach cancer. Its potential role in bowel cancer risk, however, remains hotly debated despite accumulating evidence, the researchers have explained.
In a bid to strengthen the evidence base and to inform future preventive strategies in countries with a high prevalence of H. pylori infection and limited resources, the researchers set out to estimate the extent to which exposure might be related to the global burden of bowel cancer cases.
To do this, they drew on data from systematic reviews and pooled data analyses, stratified by several factors, including region, diagnostic method, sex, access to a national bowel cancer screening programme and the use of eradication therapy. International estimates of bowel cancer cases were derived from the Global Cancer Observatory (GLOBOCAN) for 2022.
The analysis revealed that exposure to H. pylori was associated with a 1.6-fold greater risk of bowel cancer than no exposure. No statistically significant differences emerged when the data were categorised by sex, age (above and below 60 years), diagnostic method or the presence of a national bowel cancer screening programme.
In the four observational studies that reported on this measure, H. pylori eradication therapy was associated with a reduced risk of the disease but only after ten years had passed.
Globally, pooled risk estimates from 43 studies, encompassing around 48.7 million people, have indicated that H. pylori exposure might be linked to 22 per cent of bowel cancer cases. The estimated proportion attributable to exposure was found to be considerably lower, however, when the analysis was restricted to 14 population-based and cohort studies at the lower level of 12 per cent.
When the data were stratified by region and country, the Western Pacific and Mongolia recorded the highest estimated proportions of cases potentially linked to H. pylori exposure, at 25 per cent and 36 per cent respectively. This contrasts with Africa, South-East Asia and the Eastern Mediterranean, where H. pylori prevalence is similarly high but the estimated proportion of cases attributable to exposure is comparatively lower.
Exploratory data pattern analysis has suggested that the proportion of bowel cancers linked to exposure was greater among those born in more recent decades. The proportion rose from 9.5 per cent among those born before 1947, then very slightly higher to around ten per cent among those born between 1948 and 1962, and jumping to 15 per cent among those born between 1963 and 1977.
The researchers have pointed out that many potentially influential risk factors exist in the development of bowel cancer. These include non-modifiable factors, such as genetics and age, as well as modifiable factors related to lifestyle and diet, and worldwide these account for a larger estimated proportion of bowel cancer cases than H. pylori, they added.
“Population-level H. pylori control may help to prevent gastric cancer and, if the link with bowel cancer is causal, could reduce this burden in high-prevalence areas.
“However, success depends on local epidemiology, healthcare capacity and integration with existing bowel cancer screening,” the researchers have highlighted.
“As with primary gastric cancer prevention, large-scale H. pylori eradication raises concerns about antibiotic stewardship and resistance, and treatment side effects,” they said
The findings underscore the importance of well-designed randomised clinical trials and other prospective investigations to evaluate the impact of H. pylori and its eradication on bowel cancer risk, as well as potential modifying factors, the researchers have concluded.
For further reading please visit: 10.1136/egastro-2026-100436
Lab Asia 33.4 - August 2026
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