Background: Inflammatory bowel disease (IBD) develops from a dysregulated immune response influenced by environmental exposures. Radon, a radioactive gas, has known biological effects, but its role in IBD remains unexplored.
Objectives: To examine the association between residential radon exposure and the risk and clinical course of IBD.
Design: A case-control study with 1-year prospective follow-up of cases.
Methods: We included 178 newly diagnosed IBD patients and 178 age- and sex-matched controls in Santiago de Compostela, Spain, from June 2020 to September 2023. Residential radon levels were measured using passive detectors for 3 months. Outcomes included IBD diagnosis, disease extent, hospitalizations, and flares. Logistic regression was used to estimate odds ratios adjusted for age and sex.
Results: Median residential radon was 144.5 Bq/m3 in IBD cases and 189.5 Bq/m3 in controls. Higher radon levels were associated with reduced odds of IBD (OR 0.5 for 100-299 and >299 Bq/m3 vs 0-99 Bq/m3). No significant association was found between radon levels and hospitalizations or flares. Among ulcerative colitis patients, higher radon was linked to more extensive disease.
Conclusion: Higher residential radon exposure might be inversely associated with IBD risk. However, it does not appear to influence disease progression. Further studies are needed to confirm these findings, since this is the first study on this topic, and chance or selection bias might be present.
Keywords: Crohn’s disease; environmental factors; inflammatory bowel diseases; radon; ulcerative colitis.
Does radon in homes affect the risk and severity of inflammatory bowel disease? This study looked at whether home radon levels affect inflammatory bowel disease (IBD). People with IBD had lower radon exposure than those without. Higher radon levels were linked to less IBD, but didn’t affect how the disease progressed. Radon might play a protective role, especially in ulcerative colitis cases.
© The Author(s), 2025.