Larfors G, et al. - Researchers performed a population-based, retrospective case–control study to determine if chronic Helicobacter pylori infection could be a risk factor for chronic myeloid leukemia (CML), given an increased CML risk after peptic ulcer has been reported previously. For this purpose, they used Swedish registry data about 980 patients with CML and 4,960 age- and gender-matched controls. A significantly increased risk of CML was observed in relation to previous diagnoses of dyspepsia, gastritis or peptic ulcers, as well as previous proton pump inhibitor medication. Meanwhile, there was no link of inflammatory bowel disease or consumption of NSAIDs with CML, suggesting that it is not gastrointestinal ulcer or inflammation per se that affects risk. Overall, a shared background between gastric conditions and CML was indicated by the observed consistent links. These links also reinforce the case that Helicobacter pylori could constitute this common risk factor.