A 43K-Woman Study Linked This Invisible Gas To A Higher Risk Of Heart Failure
You probably don't think much about the air inside your home beyond the occasional switch of an air filter, but there's another potential concern you can't see or smell.
Radon is a radioactive gas that forms naturally when uranium in soil and rocks breaks down. It can travel up through the ground and enter buildings, where it may accumulate over time. Because it's colorless, odorless, and tasteless, you can't tell whether your home has elevated levels without testing, but the Environmental Protection Agency (EPA) estimates that roughly one-quarter of the U.S. population lives in areas where radon levels exceed the safe threshold.
If you've heard of radon before, it was probably in reference to its link to lung cancer. Now, new research1 published in JAMA Network Open suggests the gas may also have implications for heart health.
About the study
Researchers examined whether long-term indoor radon exposure was associated with heart failure in 43,188 postmenopausal women enrolled in the Women's Health Initiative. The researchers tracked participants' health through February 2024. None of the women had heart failure when they joined the study between 1993 and 1998.
Using participants' home addresses and county-level EPA data, researchers estimated radon exposure in three categories—below 2, between 2 and 4, and above 4 picocuries per liter of air. They then looked for patterns that may reveal how radon levels are associated with heart disease.
For context, the EPA recommends taking action when indoor radon reaches 4 picocuries per liter of air or higher. This measurement simply describes how much radioactive radon is present in the air. Levels below 2 are considered lower exposure, while levels above 4 are high enough to warrant attention.
Higher radon exposure increased risk of heart failure
Over an average of 16 years, 3,446 women in the study developed heart failure. Women living in areas with radon levels above the EPA's action threshold had a 19% higher risk of developing heart failure than those in areas with the lowest levels. This association remained even after researchers accounted for factors such as smoking, blood pressure, and existing health conditions.
The risk was even higher for other heart-related outcomes.
Women in high-radon areas had a 24% higher risk of heart failure with reduced ejection fraction (when the heart can't pump blood as effectively as it should) and a 37% higher risk of dying from heart failure.
By age 90, nearly 12% of women in the highest-exposure group had developed heart failure, compared with 9% in the lowest-exposure group.
Researchers estimated that the increased risk associated with radon was comparable to that linked to a 16-point increase in systolic blood pressure (the top number in a blood pressure reading).
Why does radon affect the heart?
Researchers suggest that radiation from radon may damage the cells that line the heart muscle and blood vessels, potentially triggering inflammation and cellular damage over time. However, the mechanism isn't known for sure.
This study doesn't prove radon directly causes heart failure, given that study was observational and radon exposure was estimated. Still, the findings raise questions about whether current radon safety guidelines, which focus primarily on lung cancer, should also consider cardiovascular health.
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How to check your home's radon levels
If you're concerned about radon in your home, here are some steps to take:
- Check your area's risk: Visit the EPA or your state health department website to see whether your region has elevated radon potential.
- Test your home: Pick up an inexpensive home radon testing kit. Even if you live in a lower-risk area, testing is the only way to know your indoor radon levels for sure.
- Address elevated levels: If your results are 4 picocuries per liter or higher, contact a qualified radon mitigation professional. They can recommend a system to reduce your home's radon levels. These systems are generally considered to be cost-effective fixes, yet only 2% of the highest-radon homes in this study had one installed.
The takeaway
Radon is already on the radar for lung health, but its potential connection to heart failure gives us another reason to check what's in our indoor air.
If you are unsure what the radon levels are like in your home, a testing kit can reveal an exposure you might otherwise never know was there. Even if you think radon levels in your area are low, it's better to be safe than sorry.
