Possible link between household chemical, feline hyperthyroidism

Published on November 14, 2018
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A study found that serum from hyperthyroid cats had a higher mean total concentration of per- and polyfluoroalkyl substances, found in household products including stain-repellent fabrics, compared with serum from nonhyperthyroid cats. The concentration of perfluorooctanoic acid was significantly higher in hyperthyroid cats' serum.

Researchers from the California Environmental Protection Agency and Albany Animal Hospital in Albany, California, published the results in October in the journal Environmental Toxicology and Chemistry (Environ Toxicol Chem 2018;37:2523–2529).

According to the U.S. Environmental Protection Agency: "Certain PFAS chemicals are no longer manufactured in the United States as a result of phase outs including the PFOA Stewardship Program in which eight major chemical manufacturers agreed to eliminate the use of PFOA and PFOA-related chemicals in their products and as emissions from their facilities."

In the study, researchers reported PFAS concentrations in the serum of two groups of Northern California cats older than 10 years, collected from 21 cats from 2008-10 and collected from 22 cats from 2012-13. The mean total PFAS concentration was lower in the second period than the first period, although PFAS profiles remained similar. The researchers also analyzed PFAS concentrations in human serum collected from 2008-10 in the same geographic area.

Long-chain perfluorinated carboxylic acids, particularly perfluorononanoic acid and perfluoroundecanoic acid, were significantly higher in the cats' serum than in humans. It was the serum from hyperthyroid cats in the second time period that showed a higher mean total PFAS concentration relative to serum from nonhyperthyroid cats. According to the abstract, "This result may indicate a possible link between PFAS levels and cat hyperthyroid, warranting a larger study for further investigation."

Cat dosing on a carpeted floor