Radon, even at levels below EPA mitigation guidelines, is linked to childhood leukemia

A study of more than 700 counties in several U.S. states found a link between childhood leukemia and levels of decaying radon, including those below federal mitigation guidelines. The research is published in Total Environmental Science.

The findings are important because there are few established risk factors for childhood cancer and the role of environment has not been explored much, said Matthew Bozigar of Oregon State University, who led the research. .

Radon, a natural gas, is a product of the radioactive decay of uranium, present in certain rocks and soils. When it escapes from the ground, radon itself decays and emits radioactive particles that can enter the body and accumulate in many tissues, where they can damage or destroy the DNA of cells, causing can cause cancer.

Odorless, tasteless and colorless, radon gas dilutes quickly in the open air and is generally harmless before disintegrating, but indoors or in areas with poor air circulation it can easily concentrate at high temperatures. dangerous levels and is recognized as a significant risk factor for lung cancer.

Radon, measured with small passive detectors and mitigated by passive or active ventilation in basements and crawl spaces, has not been linked to other cancers, according to the World Health Organization.

But in an 18-year statistical modeling study of 727 counties across 14 states, Bozigar and colleagues not only found a link between childhood leukemia and radon, but also at concentrations below the guidelines recommended by the Environmental Protection Agency for mitigation.

Becquerels per cubic meter are a unit for expressing the concentration of radioactive decay in a given volume of air. The EPA states that no level of radon is safe and advises taking mitigation measures when the radon concentration reaches 148 becquerels per cubic meter; the study considered concentrations as low as half of those.

“This is the largest study of its kind in the United States, but further research is needed to confirm these findings at the individual level and inform decision-making about radon-related health risks in this country and across the world. the world,” said Bozigar, assistant professor. at the OSU College of Health.

Leukemia, the most common cancer among children, affects the blood and bone marrow. About 3,000 new cases of childhood leukemia — defined in the study and by the National Institutes of Health as involving patients younger than 19 — are diagnosed each year in the United States, according to the NIH. The annual incidence rate is 4.8 cases per 100,000 children.

Boys are more likely to be diagnosed with leukemia than girls, but research suggests that radon increases the risk of leukemia in both sexes.

“Our study design only allows us to identify statistical associations and formulate hypotheses. Studies that better determine whether radon exposure causes childhood leukemia are therefore needed,” Bozigar said.

The counties examined in this study were in Washington, California, Idaho, Utah, New Mexico, Iowa, Louisiana, Kentucky, Michigan, Georgia, New York, New Jersey, Connecticut, and Massachusetts. Counties are those that, during the study period, reported their cancer data to the Surveillance, Epidemiology, and End Results Registry, a program that collects and analyzes cancer information. Known as SEER, the registry is supported by the National Cancer Institute.

Scientists from the National Cancer Institute, Harvard University and Imperial College London collaborated with Bozigar.

For Bozigar, the research has its roots in his personal experience. He grew up in Portland, which has pockets of high radon levels, and noticed what appeared to be a high incidence of cancer, especially among younger people. There have been several cancer diagnoses among his own family and friends.

“As an epidemiologist, I began to think about possible environmental causes and connected with wonderful collaborators who provided important data and other resources to enable innovative new analyses,” he said. -he declared.

“We are working on many different studies on radon and we continue to discover harmful effects that are not limited to the lungs in adults. We will have more to share in the months and years to come as our studies are completed. published.”