PBDEs Linked to Thyroid Function.
Exposure to flame-retardant chemicals known as PBDEs is associated with a decrease in a thyroid hormone critical to growth and metabolism, a new study led by School of Public Health researchers shows.
The findings of the study, published in the journal Environmental Health Perspectives, are consistent with those from animal studies showing that polybrominated diphenyl ethers (PBDEs) disrupt thyroid hormones. The study found “significant, inverse associations” between PBDE levels and serum total concentrations of a hormone known as T4 (thyroxine).
Because the researchers found no clear associations with other thyroid functions, they suggest that PBDE exposure might decrease the binding of T4 to the serum T4 binding proteins.
PBDEs have been used since the 1970s as additive flame retardants in consumer products such as electronics and furniture, especially products containing polyurethane foam. The body burdens of PBDEs found in Americans are higher than in other countries. Because of health concerns, US manufacturers voluntarily halted the use of PBDE formulations in 2004. Still, PBDEs are present in homes, offices, and vehicles and in food products.
The research team recruited 52 healthy office workers from Boston and collected serum samples at six-month intervals to assess the association between PBDE exposure and thyroid function. They collected demographic and medical information to assess confounding factors.
Studies have shown that thyroid hormones are essential for proper growth and development in utero and in infancy, as well as maintenance of metabolism and organs throughout life.
Previous studies by the SPH research team have found that people are exposed to PBDEs via indoor dust and food consumption.
The new study was led by Colleen Makey, a postdoctoral research fellow in the Department of Environmental Health. Co-authors from SPH include: Michael McClean, associate professor of environmental health; Thomas Webster, professor of environmental health; and Janice Weinberg, professor of biostatistics. Also contributing were: Lewis Braverman, Elizabeth Pearce, and Xue-Mei He of the Section of Endocrinology, Diabetes, and Nutrition at Boston University School of Medicine; and Andreas Sjodin of the National Center for Environmental Health at the Centers for Disease Control and Prevention.