A mysterious epidemic of thyroid disease in pet cats may be linked to dust shed from carpeting, upholstery and other household fabrics, according to a team of federal investigators.
Dr. Janice Dye of the U.S. Environmental Protection Agency's division in Research Park Triangle, N.C., led a team of scientists who found that contaminants called polybrominated diphenyl ethers, or PBDEs, may be involved in a disorder called feline hyperthyroidism. The chemical is used as a flame-retardant in household fabrics and was found in elevated levels in blood samples from about dozen cats nationwide.
The compound also has been found in some samples of fatty fish, such as salmon, and as a result is turning up in canned cat foods, Dye said.
"Manufacturers have been putting flame retardants in household products for about 30 years," Dye said in an interview, referring to upholstered furniture and carpeting. "Those are the perfect items that cats choose to sleep on."
"PBDEs seem to leach off in time and glom onto house dust. As a person a little may get on your skin," she said, adding that daily showering and bathing tends to get rid of it. "But if you're a cat you tend to lick it off, and because of their fastidious grooming habits they are eating a fair amount of it."
Cats who eat canned seafood-flavored products could be ingesting even more of the compound, which have PBDE levels 12 times as high as dry-food diets. Dye said pet cats might be receiving as much as 100 times greater dietary PBDE exposures than adult humans.
Feline hyperthyroidism causes exceptionally high heart and metabolic rates. The condition is similar to Graves disease in humans. "Our results showed that cats are being consistently exposed," Dye said.