AUTHOR=Kudo Hiromi , Yoshinaga Shinji , Li Xiaoliang , Lei Shujie , Zhang Shouzhi , Sun Quanfu , Koriyama Chihaya , Akiba Suminori , Tokonami Shinji TITLE=The First Attempt to Reevaluate Radon and Thoron Exposure in Gansu Province Study Using Radon-Thoron Discriminating Measurement Technique JOURNAL=Frontiers in Public Health VOLUME=Volume 9 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.764201 DOI=10.3389/fpubh.2021.764201 ISSN=2296-2565 ABSTRACT=Although epidemiological studies provide evidence for an increased risk of lung cancer risk associated with residential radon, an issue of radon-thoron discrimination remains to be solved. In this study, an updated evaluation of lung cancer risk among residents in Gansu, China was performed where one of the major epidemiological studies on indoor radon demonstrated an increased risk of lung cancer. We analyzed data from a hospital-based case-control study including 30 lung cancer cases and 39 controls with special attention to internal exposure assessment based on the discriminative measurement technique of radon isotopes. Results from analyses showed non-significant increased lung cancer risks; odds ratios adjusted for age, smoking and total income were 0.35 (95% confidence interval (CI): 0.07 - 1.74) and 0.27 (95% CI: 0.04 - 1.74) for groups living in residences with indoor radon concentrations of 50 - 100 Bq m-3 and over 100 Bq m-3, respectively, compared to those with less than 50 Bq m-3 indoor radon concentrations. Although the small sample size hampers the usefulness of present analyses, our study suggest that reevaluation of lung cancer risk associated with residential radon in epidemiological studies will be required on the basis of precise exposure assessment.