Residential Radon Exposure in the United States: a Scoping Review

Introduction: Radon, a naturally occurring gas, is the second leading cause of lung cancer in the United States (U.S.), contributing to 21000 deaths and $2 billion in economic costs. Despite decades of research, epidemiological studies on residential radon exposure and lung cancer outcomes have yielded inconsistent results, which provides justification for this study. Methods: This scoping review systematically examined the national literature on residential radon exposure and radon-induced lung cancer in the U.S. A comprehensive search strategy was employed across four databases, including 13 relevant studies. These studies, conducted across various states, employed diverse methodologies and radon detection techniques. Results: The dominant factors in radon exposure and its correlation with lung cancer risk included variations in radon levels in homes and their correlation with water supply radon levels. Elevated radon concentrations near certain geological formations, like Reading Prong granites, are linked to increased lung cancer mortality. Despite some paradoxical associations, there's a general trend of increased lung cancer mortality with higher radon exposure, especially above values recommended by the U.S. Environmental Protection Agency (EPA). Discussion: Challenges such as methodological variability and potential biases were identified, highlighting the need for further research to elucidate the underlying mechanisms and guide targeted interventions. Conclusion: The broad variation in radon exposure levels between states and the observed association in specific regions highlights the importance of continued targeted research by state and public health initiatives to minimize radon exposure. Radon disparities and potential confounding factors by state highlight the need for more focused research to include the state radon profile and other geographical variations.