A recent study has linked for the first time thyroid disease with human exposure to perfluorooctanoic acid (PFOA), a persistent organic chemical used during the process of making common household and industrial items, including nonstick cookware, flame-resistant and waterproof clothing, wire coatings, and chemical-resistant tubing. It can also be formed by the breakdown of certain other highly fluorinated chemicals used in oil- and grease-resistant coatings on fast-food containers and wrappers, as well as in stain-resistant carpets, fabrics, and paints.

     The researchers found that individuals with the highest 25 percent of PFOA concentrations were more than twice as likely to report being on medication for current thyroid disease as individuals with the lowest 50 percent of PFOA concentrations. The study included 3,966 adults 20 or more years of age whose blood serum was sampled between 1999 and 2006. Numerous animal studies show that PFOAs can affect the functioning of the mammalian thyroid hormone system, which is essential for maintaining heart rate, regulating body temperature, and supporting many other body functions, including metabolism, reproduction, digestion, and mental health.

     Tamara Galloway, professor of ecotoxicology at the University of Exeter (U.K.) School of Biosciences and the study's lead author, says that the results highlight a need for further research into human health effects of low-level exposures to environmental chemicals like PFOA that are widespread in the environment, including people's homes. However, Galloway stresses that the evidence from the new study does not rule out the possibility that having thyroid disease changes the way the body handles PFOA.

--Source: "Stain Repellent Chemical Linked to Thyroid Disease in U.S. Adults," NIH National Institute of Environment Health Sciences, January 21, 2010