Article publication date
September 2025
ARPANSA review date
March 2026
Summary
This Spanish case-control study investigated the association between indoor radon and inflammatory bowel disease (IBD). The study included 178 cases and 178 controls that were matched by age and sex. Residential radon levels were measured using passive detectors for three months in each subject’s home. The study investigated if higher residential radon exposure was associated with a high incidence of IBD and whether it increased the incidence of IBD disease flares (followed for one year) among the cases. The study found no association between increased rates of IBD and high indoor radon, even in the highest exposure category of >299 Bq/m3 (odds radio (OR) 0.5, 95% confidence interval, CI, 0.3-0.9). The study also found no association between increased occurrences of flares and the highest category of indoor radon levels (OR 1.5, 95% CI 0.5–4.5). Overall, the authors concluded that higher residential radon exposure was not associated with IBD.
Published in
Therapeutic advances in gastroenterology
Link to study
Commentary by ARPANSA
This study contributes to the emerging evidence on residential radon exposure and IBD. A previous ecological study in Spain also found no association between higher indoor radon and Crohn's disease or other types of IBD (Mauriz-Barreiro et al 2022). Previous studies of radon exposure have mostly focused on the association between radon and lung cancer. However, a recent systematic review and meta-analysis of 129 studies (Henyoh et al 2024) investigated the association between radon and diseases other than lung cancer, and found no association between radon and these outcomes.
Radon is a naturally occurring radioactive gas that can build up in poorly ventilated areas, particularly in caves and mines, however, it can also build up in home that do not have airflow. Homes that are well ventilated, made of timber or built on stumps have lower radon levels compared to homes on concrete slabs with brick walls. More information can be found on our factsheet Radon exposure and health | ARPANSA. An Australian Radon measurement survey of more than 3300 Australian homes found that that the average concentration of radon is much lower (10 Bq/m3) than global average (40 Bq/m3) (Radon in homes survey and indoor radon map | ARPANSA). This low residential radon level is unlikely to pose any health risk as it’s far below the recommended reference action limit of 200 Bq/m3.
