Household chemicals may be causing cat disease

''Digit'' the cat sits on an examination table below IV bags in a Mississauga veterinary clinic March 30, 2007. Common flame retardants meant to keep families safe from fire may be contributing to a rash of thyroid disease in household cats, U.S. researchers said on Wednesday.

CHICAGO (Reuters) - Common flame retardants meant to keep families safe from fire may be contributing to a rash of thyroid disease in household cats, U.S. researchers said on Wednesday.

They said polybrominated diphenyl ethers or PBDEs -- used in televisions, carpeting, furniture and mattresses -- were found in especially high levels in cats with hyperthyroidism, one of the most common and deadly diseases in older cats.

"We definitely found evidence that cats are being exposed to these compounds based on the level of compounds in their blood," said Janice Dye, a researcher with the U.S. Environmental Protection Agency, whose study appears in the journal Environmental Science & Technology.

Dye and colleagues now believe the chemicals may be linked with this common disease in cats.

Although hyperthyroidism was a relatively rare disease 35 years ago, it has become a leading cause of death among U.S. pet cats. Symptoms include weight loss despite increased appetite, hair loss and irritability.

Dye, a veterinarian, tied a spike in this disease to the introduction of PBDEs into homes as a flame retardant about 30 years ago. "The increased use of these chemicals tracked the increased recognition of this syndrome in kitties," Dye said.

She believes dust from the chemicals may be ingested by cats as they groom themselves.

"Cats are in this perfect position to be near the products these chemicals were put in to reduce flammability. They're in our homes. They're sleeping on our mattresses and furniture," she said.

She and colleagues analyzed blood serum levels of 23 cats, 11 of which had hyperthyroidism. They found cats had 20 to 100 times higher PBDE levels than the average U.S human adult.

PBDEs were detected in all the cats studied, but the highest levels of exposure were found in the cats with hyperthyroidism, she said. "We haven't proven it yet," but it should be studied.

The researchers said there is no evidence to link human thyroid disease with PBDEs. "If this truly is linked, we should look more closely in people as well," Dye said.

Dye said of the three main types of the chemicals, two forms have been banned and a third may be banned shortly. But because the products are used on items such as mattresses, it may take some time for them to be completely removed from the home, she said.