A global risk-attribution analysis suggests that exposure to Helicobacter pylori may be associated with 22% of colorectal cancer cases worldwide. Researchers pooled data from 43 studies involving nearly 48.7 million people and found that H. pylori exposure was associated with a 1.6-fold higher risk of colorectal cancer compared with no exposure. However, the estimated attributable fraction fell to 12% when the analysis was restricted to 14 population-based and cohort studies.
The analysis also found that H. pylori eradication was associated with lower colorectal cancer risk in four observational studies, but the reduction appeared only after 10 years. The authors stress that randomized and prospective studies are needed to determine whether eradication actually prevents colorectal cancer.