Climate Change, Radon Exposure and Lung Cancer

PI Tomi Akinyemiju, School of Medicine/Duke Cancer Institute

Valerie A. Smith, Population Health Sciences, Biostatistics Team

Jim Zhang, Nicholas School of the Environment

Amie Koch, School of Nursing

Jeffrey Clarke, School of Medicine/Duke Cancer Institute, Thoracic Oncology

Phillip Gibson, NC Department of Health and Human Services

Racial Disparities in Radon Exposure, Awareness and Lung Cancer Risk in North Carolina Lung cancer is the leading cause of cancer deaths globally, in the United States and in North Carolina. Cigarette smoking is associated with 85% of all lung cancer cases, however 15-25% of cases occur in never-smokers. Exposure to radon, classified by the World Health Organization and the Environmental Protection Agency as a human carcinogen, is the second leading risk factor for lung cancer, and the leading cause of lung cancer among never-smokers. The risk of lung cancer mortality due to the lifetime exposure of radon at 4 picoCuries per liter of air is 7 in 1,000 for never-smokers, and 62 in 1,000 for smokers. While the prevalence of cigarette smoking has declined over the past few decades, rates of non-smoking associated lung cancer have almost doubled—increasing from 8% in 1990-1995 to 15% in 2011-2013, highlighting an urgent need to better characterize the impact of radon exposure on lung cancer risk and develop state-wide mitigation strategies. Radon gas results from the decay of uranium and radium is found in most soil and rocks. Radon is drawn into buildings, causing prolonged exposure in the absence of radon remediation. Alarmingly, radon exposure is projected to increase over the coming decades due to direct and 

indirect effects of climate change. First, permafrost thawing due to increasing global temperature results in greater leakage of radon gas into the atmosphere and into residential buildings, leading to higher exposure. Second, increased air conditioning and fan usage, necessitated by increasing temperatures, leads to decreased air exchange rates in tightly sealed homes, increased radon concentrations on upper floors where residents spend greater amounts of time, and higher radon concentration and exposure. There are stark and concerning disparities in radon exposure; recent data from the BRFSS indicates that in 2019, only 14% of Hispanics had any knowledge of radon gas, compared with 37% of Black residents and 65% of White residents. Further, 68% of renters had no awareness of radon gas, compared with 37% of homeowners; and 88% of residents below the poverty level had no awareness of radon gas, compared with 29% of residents above the poverty level. Concerted strategies are needed to better characterize radon exposure among NC residents, develop programs targeting high-risk residents to raise awareness and promote the use of radon remediation, and monitor radon associated lung cancer risk in NC as the effects of climate change continue to spread globally. In this proposal, we will: 1. Characterize radon exposure, awareness, and testing among NC residents by race/ethnicity, gender, income, and neighborhood. We will integrate existing data from the BRFSS, EPA, and NC Department of Health and Human Services to generate predictive models identifying hot spots of radon exposure. We will also examine how these outcomes vary by key social determinants of health i.e., rural/urban, access to care, residential segregation 2. Examine the prevalence of radon mitigation approaches in NC by race/ethnicity, gender, income, neighborhood, and facility type (residential buildings, schools, hospitals). We will utilize existing data from the NC Multiple Listing Service (MLS) for residential buildings, and survey building managers for schools, large businesses, and hospitals to characterize use of radon mitigation approaches 3. Estimate the relative impact of smoking and radon exposure on lung cancer risk among NC residents. We will analyze incident lung cancer data from the NC Cancer Registry and examine the risk of lung cancer in regions characterized by high vs. low radon exposure, stratified by race/ethnicity and smoking status, to identify areas of high lung cancer risk.