Women with elevated levels of common types of flame retardant chemicals in their blood may be at a higher risk for thyroid disease—and the risk may be significantly higher among postmenopausal women, according to a new study from researchers at Harvard T.H. Chan School of Public Health.
The new paper is the first to suggest a link between polybrominated diphenyl ethers (PBDEs) and increased risk of thyroid problems in postmenopausal women in a nationally representative sample of women in the U.S.
The study was published online May 23, 2016 in the journal Environmental Health.
“These chemicals are just about everywhere, from the blood in polar bears to eagles to humans on every continent,” said Joseph Allen, assistant professor of exposure assessment science at Harvard Chan School and the study’s lead author. “This near ubiquitous exposure means we are all part of a global experiment on the impact of endocrine disrupting chemicals on our bodies.”
PBDEs have been used as flame retardants for decades, largely in furniture, in quantities up to 20% of the weight of the product. Over time, they migrate out of the furniture into the air, settle into dust in homes, schools, offices, and the outdoors, and accumulate in people’s bodies. Previous research has shown that these chemicals accumulate in fatty tissue and interfere with hormonal functions, including interference with thyroid hormones. Because it’s known that estrogen levels regulate thyroid hormones, researchers theorized that postmenopausal women may be particularly vulnerable to PBDE-induced thyroid effects.