PBDE Flame Retardants May Increase Risk of Thyroid Disease: Study

New research suggests that women with higher concentrations of flame retardants in their blood may be more susceptible to thyroid complications, raising concerns that the commonly encountered chemicals may cause an estrogen imbalance. 

In a study published in the journal Environmental Health on May 24, researchers indicate that higher elevations of flame retardant chemicals known as polybrominated diphenyl ethers (PBDEs) may decrease estrogen reserves required to maintain proper thyroid function.

Lead author Joseph Allen, of the Harvard T.H. Chan School of Public Health, and a team of researchers analyzed self-reported data from the National Health and Examination Survey on thyroid problems reported among women from 2003 through 2004, to test for an association between serum PBDE concentrations and thyroid disease. The researchers further separated the data collected by menopause status to determine the effect on estrogen level production.

PBDEs are commonly used in the making of fire resistant clothing and upholstery, and are also found in pharmaceuticals, cosmetics, pesticides, plastics, detergents, food, and toys, according to the U.S. National Institutes of Health.

According to Allen, PBDEs are a class of chemicals that interfere with human’s endocrine system by disrupting the body’s production of the hormone estrogen. Since balanced estrogen levels are essential to maintaining healthy thyroid function, which controls metabolism, the researchers sought to determine the effects of various concentration levels of PBDEs in the blood in women who were pre and post-menopausal.

The study identified that women who had the highest concentrations of PBDES in their blood were 48% to 78% more likely to suffer from thyroid complications and thyroid disease. The data indicated 24% of post-menopausal women reported having thyroid issues at some point, compared to only 12% of pre-menopausal women.

Allen and his team of researchers concluded that since pre-menopausal women are able to produce estrogen at more frequent rates, the effects of PBDE exposures were not as likely to cause thyroid complications. However, women who are post-menopausal, and not creating estrogen levels at such frequent rates, may be more susceptible to thyroid complications from exposure to the chemicals.

PBDE Endocrine Disruptor Risks

Researchers and experts have expressed health concerns about flame retardant chemicals used in clothing and furniture, due to the ability of the chemicals to release into the air and accumulate in dust that humans breathe. Previous studies have shown that certain PBDEs used as flame retardants can accumulate in fatty tissues and disrupt hormone function. Various other studies have linked endocrine disruptors, such as PBDEs, to developmental, reproductive, and neurological and immune system problems.

According to the U.S. Centers for Disease Control and Prevention (CDC), the extent of health effects caused by PBDE exposure in humans is unknown. However studies on rats and mice indicated the consumption of food with moderate amounts of PBDEs for a few days began causing thyroid gland complications. Additional tests with PBDEs in food at lower levels for longer periods of time indicated effects on the thyroid and liver in the test animals. The data suggests that high concentrations of PBDEs may cause neurobehavioral alterations and affect the immune system in animals.

In February 2015, the Journal of Reproductive Immunology published a study which found that women with higher levels of flame retardant chemicals in their amniotic fluid and cord blood were more likely to give birth to a premature baby.

The research indicated that the body’s exposure to PBDEs may cause or enhance inflammation in the placenta, resulting in preterm births which have been linked to serious health complications, including breathing problems, respiratory distress, heart problems, brain hemorrhage, gastrointestinal issues, anemia, jaundice, weakened immune system, cerebral palsy, vision problems, hearing loss and may even result in death.

In 2014, a study published in Environmental Health Perspectives found that fetuses exposed to PBDEs during pregnancy had a decreased I.Q. of 4.5 points by the age of five and were more susceptible to hyperactivity.

Due to the large scale use of PBDEs in commercial products over the last few decades nearly everyone is exposed to some degree of fire-resistant chemicals and the extent of the risks are still unknown.

In June 2014, Kaiser Permanente announced they would no longer be purchasing furniture made with flame retardants following the new medical evidence surfacing about the side effects of fire resistant chemicals.