• Posted February 1, 2024

'Hidden Killer' Radon Could Raise Your Stroke Risk

Radon, an invisible, naturally occurring radioactive gas, appears to raise a person's risk of stroke, a new study suggests.

Already known as the second leading cause of lung cancer, these new findings suggest exposure to radon can increase risk of stroke by as much as 14%, according to a report published Jan. 31 in the journal Neurology.

“Our research found an increased risk of stroke among participants exposed to radon above -- and as many as two picocuries per liter (pCi/L) below -- concentrations that usually trigger Environmental Protection Agency (EPA) recommendations to install a home radon mitigation system,” said researcher Dr. Eric Whitsel, a professor of epidemiology and medicine at the University of North Carolina in Chapel Hill.

Radon is produced when metals like uranium or radium break down in rocks and soil, researchers said. The gas can make its way into homes through gaps around pipes and cracks in basement walls and floors.

For the new study, researchers tracked nearly 159,000 women with an average age of 63, none of whom had suffered a stroke at the start of the study.

The team followed participants for an average of 13 years, during which there were nearly 7,000 strokes.

Researchers used participants' home addresses to gather radon concentration data from the U.S. Geological Survey and the EPA.

EPA standards recommend that average indoor radon concentrations do not exceed four pCi/L, researcher said. If levels go that high, the agency recommends installing a system to lower radon levels in the home.

Researchers divided participants into three groups – those with concentrations that exceeded the EPA limit, those with levels between two and four pCi/L, and those with levels of less than two pCi/L.

The group with the highest radon exposures had 349 strokes per 100,000 person-years, compared to 343 strokes in the middle group and 333 strokes in the group with lowest exposure.

Put another way, participants in the high radon group had a 14% increased risk of stroke compared to the lowest group, and the middle group had a 6% increased risk.

“It's important to note that we found an increased stroke risk among those exposed to radon concentrations as much as two pCi/L below the current lung cancer-based threshold for recommending radon mitigation,” Whitsel said in a journal news release. “More studies are needed to confirm our findings. Confirmation would present an opportunity to improve public health by addressing an emerging risk factor for stroke."

More information

The U.S. Environmental Protection Agency has more about radon.

SOURCE: American Academy of Neurology, news release, Jan. 31, 2024