Chemical Flame Retardants Linked to Thyroid Disease in Cats

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In the new study, published in the Aug. 15 online issue of Environmental Science & Technology, Birnbaum and her colleagues took blood samples from 23 cats, 11 of which suffered from hyperthyroidism. They found that the cats with the disease had levels of PDBEs that were three times higher than younger cats and cats without the condition.

PBDEs are also found in canned cat food, particularly in fish/seafood flavors, such as salmon and whitefish. An analysis showed that diets based on canned food could have PBDE levels 12 times higher than dry-food diets. For these reasons, cats could be receiving as much as 100 times greater dietary PBDE exposure than American adults, the researchers said.

The danger of feline hyperthyroidism might be higher in the United States, where people have the highest reported PBDE levels worldwide, according to the report. In addition, by the late 1990s, North America accounted for almost half of the worldwide demand for PBDEs for commercial materials such as furniture and upholstery.

The epidemic of hyperthyroidism in cats began almost 30 years ago, experts say, at the same time that PBDEs were introduced into household materials for fire-prevention. Now the disease has been seen in Canada, Australia, Japan and many parts of Europe.

Hyperthyroidism has also increased in people. For example, former President George H.W. Bush and First Lady Barbara Bush have the condition, as does Millie, their Springer Spaniel.

More information

For more information on PBDEs, visit the Washington State Department on Ecology.