Pet Cats Serving as Canaries for a Home Pollutant

Hyperthyroidism in cats was virtually unknown three decades ago. But it has become common, particularly in older pets. As in people, cats’ overactive thyroids can lead to weight loss, rapid heartbeat and other problems.

The increase in feline hyperthyroidism coincides with the advent of flame-retardant chemicals known as PBDEs, or polybrominated diphenyl ethers, in materials like carpet and upholstery padding, plastics and electronic equipment. So a study by Janice A. Dye of the Environmental Protection Agency and colleagues sought to explore possible links between the chemicals and the condition.

The researchers analyzed PBDE levels in serum from three groups of cats: young and healthy, hyperthyroid older cats and older cats with other diseases. Because of variability in each group, it was not possible to associate hyperthyroid cats and total PBDE levels. But over all, as the researchers report in Environmental Science and Technology, PBDE levels were high in all cats, 20 to 100 times greater than in humans.

This may be because of cats’ diets (the researchers analyzed PBDEs in cat food, and found canned seafood-flavor food in particular had relatively high levels) and because they spend so much time on or near furnishings. Being meticulous groomers, cats may ingest PBDE-laden dust picked up from couches and carpets.

The researchers say more work is needed to explore the link between PBDEs and thyroid activity. What is clear, they say, is that cats are highly exposed to PBDEs, and thus may serve as a sentinel for understanding the effects of human exposure to the chemicals.
more from the NY Times