Do PBDEs cause thyroid disorders in pets?

I'm on a environmental tox kick lately. The latest foray into endocrine disruption in the news is polybrominated diphenyl ethers, or PBDEs. PBDEs are used as flame retardant compounds, and like my earlier ruminations on bisphenol A, they're in everything. Unfortunately, there's evidence that they don't just sit there, but rather, as the LA Times reports, they like to impersonate thyroid hormone and may lead to hyperthyroidism.

An epidemic of thyroid disease among pet cats could be caused by toxic flame retardants that are widely found in household dust and some pet food, government scientists reported Wednesday.

The often-lethal disease was rare in cats until the 1980s, when it began appearing widely, particularly in California cats. That was at the same time industry started using large volumes of brominated flame retardants in consumer products, including furniture cushions, electronics, mattresses and carpet padding.

Scientists from the Environmental Protection Agency noted a possible connection between hyperthyroidism and flame retardants. The chemicals -- known as polybrominated diphenyl ethers, or PBDEs -- mimic thyroid hormones, so experts have theorized that high exposure in cats could cause overactive thyroids.

Cats that remain indoors and eat fish-flavored canned food were found to be the most highly contaminated.

Looks like melamine ain't the only thing Toto's gotta watch out for, Dorothy.

"It is clear that house cats may be able to serve as sentinels for indoor exposure to PBDEs for humans who share their houses," said Birnbaum, one of the world's leading experts on hormone-altering chemicals.

Brominated flame retardants are ubiquitous outdoors and inside homes. The chemicals have been building up in people and wildlife over the last two decades, particularly in the United States, where human concentrations have doubled every few years.

People in the United States have the highest PBDE levels in humans worldwide, but U.S. cats are even more exposed -- some with levels 100 times greater, according to the study.

Twenty-three cats were tested in the EPA's study, including 11 with hyperthyroidism. The researchers found that the cats with hyperthyroidism had substantially higher levels of a PBDE compound. Symptoms of the disease, which is a leading cause of cat death, include weight loss, rapid heartbeat and irritability.

Ok so this study is small. But the idea of using cats as sentinels for high PBDE concentrations-- and thus indicators of areas where humans may be at risk-- is particularly noteworthy, especially since the US has such high accumulations of PBDEs in its environs. So far, though, my stupid cat seems fine. This might explain, however, my ex-wife's spooky cat...

This is your cat on PBDEs. Ok not really.