A recent study examining over 700 counties in various U.S. states revealed a connection between childhood leukemia and the levels of decaying radon gas, even when these levels fall below federal guidelines for mitigation.
A recent study examining over 700 counties in various U.S. states revealed a connection between childhood leukemia and the levels of decaying radon gas, even when these levels fall below federal guidelines for mitigation.
The results are significant as there are few known risk factors for childhood cancer, and the environmental impact has not been widely investigated, said Oregon State University researcher Matthew Bozigar, who led the study.
Radon is a naturally occurring gas that is produced by the radioactive decay of uranium, which can be found in some rocks and soil. As radon escapes from the earth, it decays and gives off radioactive particles that can enter the body and accumulate in various tissues, potentially damaging or destroying DNA in cells and leading to cancer.
Since radon gas is colorless, odorless, and tasteless, it usually disperses quickly in open air and is not harmful until it decays; however, indoors or in poorly ventilated spaces, it can build up to hazardous levels and is known to significantly increase the risk of lung cancer.
Radon levels are measured with small passive detectors and can be reduced through passive or active ventilation methods in areas like basements and crawl spaces. According to the World Health Organization, radon has not been linked to other forms of cancer. Nonetheless, in an 18-year statistical analysis involving 727 counties across 14 states, Bozigar and his team discovered a correlation between childhood leukemia and radon, even at levels lower than the Environmental Protection Agency’s (EPA) mitigation guideline.
Becquerels per cubic meter denotes the concentration of radioactive decay within a specific volume of air. The EPA asserts that no level of radon is completely safe and recommends mitigation when radon concentrations reach 148 becquerels per cubic meter; the current study analyzed concentrations as low as 74 becquerels.
“This is the largest study of its kind in the U.S., but further in-depth research is essential to validate these results individually and help guide health risk assessments relating to radon both in the U.S. and worldwide,” stated Bozigar, who is an assistant professor at OSU’s College of Health.
Leukemia is the most common cancer type in children, affecting the blood and bone marrow. The National Institutes of Health (NIH) reports approximately 3,000 new cases of childhood leukemia — which affects individuals up to the age of 19 — are diagnosed annually in the United States. The incidence rate is about 4.8 cases per 100,000 children each year.
While boys are generally at a higher risk for a leukemia diagnosis than girls, the study indicates that radon exposure increases the risk for both genders.
“Our study design gives us the ability to identify statistical correlations and propose hypotheses, but further research is needed to establish whether radon exposure directly causes childhood leukemia,” Bozigar noted.
The counties involved in this research were located in Washington, California, Idaho, Utah, New Mexico, Iowa, Louisiana, Kentucky, Michigan, Georgia, New York, New Jersey, Connecticut, and Massachusetts. These counties were part of the study period that reported their cancer data to the Surveillance, Epidemiology, and End Results (SEER) registry, a program that gathers and analyzes cancer statistics, supported by the National Cancer Institute.
Bozigar collaborated with scientists from the National Cancer Institute, Harvard University, and Imperial College London for this research, which was funded partly by the EPA and published in Science of the Total Environment.
For Bozigar, this research stems from personal experiences. Growing up in Portland, an area known for certain high radon levels, he noticed what seemed to be a higher occurrence of cancer, especially in younger populations, with multiple cancer cases among his family and friends.
“As an epidemiologist, I began exploring potential environmental factors and teamed up with exceptional collaborators who provided critical data and resources for innovative analyses,” he explained. “We are investigating various radon-related studies and are continuing to discover adverse effects beyond just lung issues in adults. We look forward to sharing more findings in the forthcoming months and years as our research is released.”
