Exposure to even moderate levels of radon linked to increased risk of stroke

Feb. 19, 2024
Radon is the second leading cause of lung cancer.

A new study has found exposure to radon is also linked to an increased risk of stroke.

The study, which examined exposures in middle age to older female participants, found an increased risk of stroke among those exposed to high and even moderate concentrations of the gas compared to those exposed to the lowest concentrations. The study is published in the January 31, 2024, online issue of Neurology, the medical journal of the American Academy of Neurology. The study does not prove that exposure to radon causes stroke; it only shows an association.

The study involved 158,910 female participants with an average age of 63 who did not have stroke at the start of the study. They were followed for an average of 13 years. During the study, there were 6,979 strokes among participants.

To determine radon exposures, researchers linked participants’ home addresses to radon concentration data from the U.S. Geological Survey and the U.S. Environmental Protection Agency (EPA).

The EPA recommends that average indoor radon concentrations do not exceed four picocuries per liter (pCi/L). For concentrations this high, the EPA recommends installing a radon mitigation system to lower radon levels in the home.

Participants were divided into three groups. The highest group had homes in areas where average radon concentrations were more than four pCi/L. The middle group lived in areas with average concentrations between two and four pCi/L. The lowest group lived in areas with average concentrations of less than two pCi/L.

In the group with the highest radon exposures, there were 349 strokes per 100,000 person-years compared to 343 strokes in the middle group and 333 strokes in group with the lowest exposure. Person-years represent both the number of people in the study and the amount of time each person spends in the study.

After adjusting for factors such as smoking, diabetes and high blood pressure, researchers found participants in the highest group had a 14% increased risk of stroke compared to those in the lowest group. Those in the middle group had a 6% increased risk.

American Academy of Neurology release on Newswise