Chemicals That Mess With the Thyroid

PFC exposure may be associated with changes in thyroid hormones

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Chemicals are used in manufacturing pretty much everything we use on a daily basis. But their long-term effects on the body are often unknown.

Though major manufacturers have stopped using certain chemicals called PFCs, according to the National Institute of Environmental Health Sciences, PFC exposure continues to be widespread.

According to a new study, exposure to these chemicals may be linked to changes in thyroid hormone levels.

Problems with thyroid hormone levels have been shown to play a role in weight gain, tiredness and other health issues.

"Talk to your doctor about safe chemicals and plastics."

This study was conducted by Chien-Yu Lin, MD, PhD, of the En Chu Kong Hospital in Taiwan, and colleagues.

The aim of this study was to examine the effects of exposure to perfluorinated compounds (PFCs) on thyroid function.

Thyroid hormones act on nearly every cell in the body and are responsible for normal metabolism. Imbalances in thyroid hormones can lead to tiredness, weight issues and heart problems, in addition to a host of other disorders.

PFCs can make materials stain-, oil- and water-resistant and are widely used in the manufacture of fabrics, carpets, paper coatings, cosmetics and variety of other products.

According to this study, these chemicals may be a concern for two reasons. First, they break down very slowly so they stay in the body for a long time. Plus, not much information is available regarding their long-term effects on health.

The researchers looked at data from 1,181 participants in a population-based survey conducted by the Centers for Disease Control and Prevention (CDC). They reviewed exposure to four different kinds of PFCs and their effects on thyroid function.

After looking at the data, the researchers found that women who had higher levels of certain kinds of PFCs in their blood had elevated levels of thyroid hormones. Men exposed to PFCs tended to have lower levels of thyroid hormones.

The authors noted that the study had some limitations. First and most importantly, an association between the PFC levels and thyroid hormone levels does not indicate that the PFC levels were a direct cause of disturbances in thyroid function.

There may be other factors the study subjects had in common that could have influenced the thyroid hormone levels. Also, the study did not account for medications the subjects might have taken that could cause hormonal fluctuations.

The authors also pointed out that the observed effect of PFCs on thyroid hormones was small and may not lead to any major clinical issues in the general US population.

"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," said Dr. Lin.

The authors recommended that further research be conducted to explore this link.

The results of this study were published July 17 in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

No conflicts of interest or relevant financial disclosures were reported by the authors. Funding information for the study was unavailable.

Review Date: 
July 17, 2013
Last Updated:
August 7, 2013