Abstract 832: Gender differences in urinary tract cancer susceptibility associated with radon in water: A population based study from Finland

Abstract Background: Radon as a common source of environmental radiation, while its carcinogenic effect on urinary tract cancer has not been fully investigated. Methods: Men and women who have continuously lived in Finland from year 1987 onward and reached 40+ years old at the beginning of 2017 were followed up for urinary tract cancer, including bladder cancer (ICD-O 3 code C67) and kidney cancer (C64-C66 and C68) for 5 years until the end of 2021. The residential location and type of buildings of the cohort members were traced from year 1987 until 2016 annually and linked to the average cumulative exposure of radon concentration in well water on municipality level. Newly diagnosed UTC cases were identified based on the Finnish cancer register. Pre-existing health conditions, such as hypertension, diabetes, chronic kidney disease, calculus of kidney and lower urinary tract, family history of cancer, as well as socioeconomic factors were ascertained from multiple registry databases. Data were analyzed with Cox proportional hazards model conditional on birth cohorts and adjusted with available covariates. Findings: Among 1,019,331 men and 1,192,960 women with 30-years average radon exposure, 4206 and 2226 urinary tract cancer cases were diagnosed during follow-up period from 2017 until correspondingly. Men with higher radon exposure (>500 Bq/m3) had about 14% higher risks of UTC in total (HR 1.14, 95% CI 1.07-1.21), 19% higher risks of bladder cancer (HR 1.19, 95%CI 1.09-1.32), 10% higher risks of kidney cancer (HR 1.10, 95%CI 1.02-1.20) comparing with lower exposed samples. Women with higher radon exposure had about 1% higher risks of UTC in total (HR 1.01, 95%CI 0.93-1.10), 3% higher risks of bladder cancer (HR 1.03, 95%CI 0.88-1.22), 1% higher risks of kidney cancer (HR 1.01, 95%CI 0.92-1.11). In the sub-population who only lived in houses during the 30-years exposure period, men with higher radon exposure had about 24% higher risks of UTC (HR 1.24, 95% CI 1.12- 1.36), 30% higher risks of bladder cancer (HR 1.30, 95%CI 1.12-1.51), 20% higher risks of kidney cancer (HR 1.20, 95%CI 1.06-1.36). No significant association was observed in women who only lived in houses during exposure period. Conclusions: For men, higher radon exposure was significantly associated with elevated risks of UTC. No significant association was observed in women. Further investigates were needed to explore the mechanisms of gender differences in UTC susceptibility associated with radon exposure. Keywords: Radon, Radiation, Cancer, Urinary tract cancer, Kidney cancer, Bladder cancer Citation Format: Peng Yunzhi Li. Gender differences in urinary tract cancer susceptibility associated with radon in water: A population based study from Finland [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 832.