Radon and heart failure: high indoor levels linked to 19% higher risk after menopause

Postmenopausal women whose homes were estimated to have high levels of indoor radon had a higher risk of developing heart failure, according to a study published in JAMA Network Open on Thursday, 5 November 2026. Researchers led by the University of North Carolina's Gillings School of Global Public Health followed 43,188 women in the United States from the Women's Health Initiative, a long-running study of women's health. Women in areas with estimated radon above 4 picocuries per litre (pCi/L) had a 19% higher risk of heart failure than those below 2 pCi/L, after other risk factors were taken into account, according to reports on the study.

Radon is a radioactive gas found indoors, and research on it has mostly focused on the lungs. This study adds to a smaller body of work asking whether it is also linked to heart disease. Earlier analyses of the same group of women had looked at stroke and heart attack; this one looks at heart failure, a long-term condition in which the heart cannot pump blood as well as the body needs.

For women in midlife and later, the findings matter because they point to a possible risk factor in the home itself, alongside familiar ones such as blood pressure and weight. According to reports on the study, the authors compared the extra risk linked with high radon to the extra risk that comes with substantial rises in systolic blood pressure and body mass index. That comparison gives a sense of scale: the association was not trivial.

The study has clear limits, and they should be stated plainly. The women's radon exposure was estimated, not measured inside each home, and reports describe the method differently, with at least one saying exposure was assigned from area-level radon zones. That means the result is a link at the level of where women lived, and other unmeasured differences between areas could play a part. The researchers say it is still unknown whether reducing radon in a home lowers heart risk. Reports note that the findings need confirmation before any change to medical advice.

The study was carried out in the United States, where 4 pCi/L is the level at which the US Environmental Protection Agency advises action, according to reports. The study's figures come from US homes and cannot simply be read across to other countries.

Peepals calculation: The highest exposure group was set at more than twice the level of the lowest (above 4 pCi/L against below 2 pCi/L). Within the reported results, the rise in heart failure deaths (37%) was nearly double the rise in heart failure cases (19%): 37 ÷ 19 ≈ 1.95. The weak-pumping form of heart failure showed a rise in between, at 24%. Our calculation from the reported figures.

Short-term: The study adds heart failure to the list of health problems researchers are examining in connection with indoor radon, and is likely to prompt calls for more research.

Long-term: If later studies, ideally with radon measured inside homes, confirm the link and show that lowering radon helps, radon testing could become part of heart-health guidance as well as lung-cancer prevention.

Who is affected: Postmenopausal women, especially those with a history of smoking; doctors and public health agencies; and researchers in environmental health.

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