High Radon Levels Linked to Gestational Diabetes

New data link higher county-level radon exposure to gestational diabetes (GD) in women who haven’t previously given birth, emphasizing the need to consider environmental risks in maternal and fetal healthcare.

Yijia Zhang, PhD, with the Department of Obstetrics and Gynecology, Vagelos College of Physicians and Surgeons at Columbia University Irving Medical Center in New York, and colleagues found in a study of 9107 nulliparous pregnant women that those living in US counties with higher radon levels (2 picocuries [pCi]/L) had higher odds of developing GD than those in counties with lower (

Findings were published online on January 10 in JAMA Network Open. The researchers used data from The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b), a multicenter, prospective cohort study that examines factors associated with pregnancy-related outcomes.

“To our knowledge, this is the first study to examine the association between radon exposure and the risk of GD,” the authors wrote.

The researchers also found higher odds of GD in women who had ever smoked who lived in counties with a higher (2 pCi/L) radon level (OR, 2.09; 95% CI, 1.41-3.11) and women living in counties with both higher radon and fine particulate matter air pollutants (PM _2.5) levels (OR, 1.93; 95% CI, 1.31-2.83), though no statistically significant interactions were observed.

GD Affects 10% of Pregnancies

GD affects about 10% of pregnancies every year in the United States, according to the Centers for Disease Control and Prevention, and can affect women and offspring long term as it raises mothers’ risk of type 2 diabetes and cardiovascular disease and raises the risk for childhood obesity. Radon exposure’s link with lung cancer risk has been well established, but its link to other health risks is uncertain, the authors note.

The authors said their findings are hypothesis-generating and said, “It is vital to conduct studies that incorporate individual-level indoor radon exposure data,” to get closer to understanding the underlying mechanisms.

Individual-Level Exposure Measures Needed

They note that the average radon level in a county might not reflect an individual’s exposure and individual-level residential factors involved with radon exposure, such as household mitigation, and whether a dwelling has a basement, for instance, “are crucial for enhancing the precision of exposure assessment.”

In an invited commentary, Alberto Ruano-Ravina, PhD, and Lucía Martín-Gisbert, MSc, both with the Department of Preventive Medicine and Public Health at the University of Santiago de Compostela in Galicia, Spain, also urged that individual-level studies be conducted to further investigate radon’s link to health risks, noting that “[r]adon is possibly the most prevalent indoor carcinogen to which human beings are exposed.”

“There is no reason for not having these studies once we have some evidence of an association from ecological studies,” they wrote. They point out that reliable radon assessments are easy and inexpensive.

“The potential association of radon exposure with gestational diabetes or any other disease should be better analyzed using exclusively radon-prone areas. An observance of a dose-response effect may be indicative of a causal relationship, and it could be easily evidenced in radon-prone areas should such a relationship exist,” the commenters wrote.

Such areas have low, medium, high, and extremely high concentration levels, the commenters wrote. Zhang’s team, they point out, had to use only three exposure levels because the number of residents in high-exposure areas (exceeding 3 pCi/L) was too small.

“It is time now to move forward and really understand the full implications of radon exposure for health,” they concluded.

Co-author Mary D’Alton, MD, reported serving on the board of directors for Merck for Mothers and as a board member for March for Moms outside the submitted work. Coauthor Becky McNeil, PhD, reported grants from the National Heart, Lung, and Blood Institute and the National Institutes of Health (NIH) during the conduct of the study. Coauthors Brian Mercer, PhD; Robert Silver, MD; Samuel Parry, MD; and Ka Kahe, MD, ScD reported grants from the NIH during the conduct of the study. Coauthor Simhan, MD, reports grants from the NIH during the conduct of the study and being a cofounder of Naima Health and receiving personal fees from Organon & Co. outside the submitted work. 

Both commenters reported no relevant financial disclosures.

Marcia Frellick is an independent healthcare journalist based in Chicago.