The Relationship Between Brain Tumor Prevalence, Socioeconomic Standing, and Relative Radon Exposure Risk: A City Level Analysis in Rhode Island

Introduction: The contribution of DNA damage from ionizing radiation to carcinogenesis, including malignant and non-malignant brain cancer, is well-established. However, whether exposure to radon, a natural radiation source that decays into radioactive particles, increases the risk of brain cancer remains understudied.

Methods: We performed a pilot analysis of 501 patients with newly diagnosed primary brain tumors treated at the Rhode Island Hospital between 2020 and 2024. Patient addresses were cross-referenced with Rhode Island Department of Health (RIDOH) designations of the state’s cities as < 10% and ≥ 10% of homes with high (> 4.0 pCi/L) radon-222 levels. The expected prevalence of brain tumors for these cities (based on random distribution) was compared to the actual prevalence, with a pre-specified hypothesis that radon exposure is associated with increased brain tumor risk.

Results: The expected prevalences of primary brain tumor patients for cities with < 10% and ≥ 10% homes with high radon-222 levels were 27% and 73%, respectively. The observed primary brain tumor prevalences for these cities were 22% and 78% of patients, respectively. Given the total study population of 967,216, the difference in prevalence was statistically significant at p=0.00587. Moreover, the level of radon-222 exposure was inversely associated with the average national Area Deprivation Index (ADI) of the studied cities, with primary brain tumor patients for cities with < 10% and ≥ 10% homes with high radon-222 levels having an average national ADI of 50 and 35, respectively (p < 0.001). Since ADI is inversely related to socioeconomic standing, our results suggest that socioeconomic disparity contributes to the risk of a primary brain tumor.

Conclusion : This pilot analysis adds to the growing literature implicating radon exposure as a risk factor for primary brain tumors. The association between radon exposure and socioeconomic standing suggests potential contributions of economic disparity to primary brain tumor risk in Rhode Island. Ongoing efforts are directed toward the validation of this association.