Increased risk of chronic myeloid leukaemia following gastric conditions indicating Helicobacter pylori infection: a case-control study

Background: Based on a previous report of increased chronic myeloid leukaemia (CML) risk following peptic ulcer, we hypothesised that chronic Helicobacter pylori infection could serve as a risk factor for CML. Methods: In a population-based, retrospective case-control study we used Swedish registry data on 980 CML patients and 4 960 age- and sex-matched controls to investigate associations between markers of previous infection with Helicobacter pylori and CML incidence. Results: Previous diagnoses of dyspepsia, gastritis or peptic ulcers, as well as previous proton pump inhibitor (PPI) medication, were all associated with a significantly increased risk of CML (relative risks 1.5-2.0 p=0.0005-0.05). Meanwhile, neither inflammatory bowel disease nor intake of non-steroid anti-inflammatory drugs were associated with CML, indicating that it is not gastrointestinal ulcer or inflammation per se which influences risk. Conclusions: The consistent associations suggest a shared background between gastric conditions and CML, and strengthens the case that Helicobacter pylori could constitute this common risk factor. Impact: As the aetiology of CML is practically unknown, and Helicobacter pylori could potentially be a therapeutic target, even this indirect evidence encourages further studies on the potential involvement of Helicobacter pylori in CML aetiology.