Increased Risk of Chronic Myeloid Leukemia Following Gastric Conditions Indicating Helicobacter pylori Infection: A Case-Control Study

Background: On the basis of a previous report of increased chronic myeloid leukemia (CML) risk following peptic ulcer, we hypothesized 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 patients with CML 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 (RRs, 1.5-2.0; P = 0.0005-0.05). Meanwhile, neither inflammatory bowel disease nor intake of NSAIDs were associated with CML, indicating that it is not gastrointestinal ulcer or inflammation per se that influences risk. Conclusions: The consistent associations suggest a shared background between gastric conditions and CML, and strengthen the case that Helicobacter pylori could constitute this common risk factor. Impact: As the etiology 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 etiology.