Thyroid Irregularities Linked to Chemical Found in Cosmetics and Carpets

Exposure to perfluorinated chemicals (PFCs) -- chemicals found in items such as fabrics, carpets, cosmetics and paper coatings -- may contribute to thyroid issues, a new study found.

Published in the Journal of Clinical Endocrinology and Metabolism, the study included nearly 1,200 people who took part in the 2007-2008 and 2009-2010 U.S. National Health and Nutrition Examination Survey, which looked at levels of four different PFCs and individuals' thyroid function, among other things.

"Our study is the first to link PFC levels in the blood with changes in thyroid function using a nationally representative survey of American adults," one of the study's authors, Dr. Chien-Yu Lin of En Chu Kong Hospital in Taiwan, said in a press release.

By examining the results, the researchers found a correlation between high levels of PFCs and a change in thyroid function for both men and women, including a risk of mild hypothyroidism in women.

Hypothyroidism is caused when the thyroid doesn't produce enough of certain kinds of hormones. Because these hormones control how the body uses energy, many individuals who experience it will also experience fatigue and weakness. If left untreated, it can result in a wide range of problems, including infertility, a heart attack or a stroke.

Other symptoms include depression, weight gain, feeling cold, constipation and menstrual irregularities.

Other irregularities the researchers found included elevated levels of the thyroid hormone triiodothyronine (T3) in women who had higher levels of a PFC called perfluorooctanoate.

The study also found an increase in levels of T3 and the thyroid hormone thyroxine (T4) in women with higher concentrations of the PFC perfluorohexane sulfonate (PFHxS) in their blood. Furthermore, the levels rose without the pituitary gland following through with its task of signaling to the thyroid to produce more hormones, which is the body's natural mechanism for adjusting for thyroid hormone levels. Men exposed to higher amounts of PFHxS, on the other hand, tended to have lower levels of the T4 hormone.

Going forward, Lin says more research is needed to fully understand these pervasive chemicals.

"Although some PFCs such as PFOS have been phased out of production by major manufacturers, these endocrine-disrupting chemicals remain a concern because they linger in the body for extended periods," Lin said. "Too little information is available about the possible long-term effects these chemicals could have on human health."