A mysterious epidemic of thyroid disease among pet cats in the US may be linked to exposure to dust from flame retardants in household carpeting, furniture, fabrics and pet food.
Feline hyperthyroidism (FH) was first noticed in cats almost 30 years ago, at the same time that polybrominated diphenyl ethers (PBDEs) were introduced into household materials as a fire-prevention measure. These chemicals are now known to have endocrine-disrupting effects and cause liver and nerve toxicity in animals.
Recently, cats with FH have been found to have greatly elevated levels of PBDEs, and consumer household products are particularly implicated as sources of these chemicals, especially those that incorporate polyurethane foams such as carpet underlays, furniture and mattresses.
Indoor pets are thought to be most at-risk, especially cats, as they ingest large amounts of PBDE-laden house dust while grooming their fur. However, a cat's diet is a further risk factor for developing FH.
The PBDE content of canned fish, such as salmon and whitefish, has been found to be higher than that of dry or non-seafood canned items, and it is estimated that diets based on canned food could have PBDE levels 12 times higher than dry-food diets. It is therefore possible that pet cats might be receiving as much as 100 times more dietary PBDE exposure than American adults.
As cats and humans are the only mammals with high incidences of hyperthyroidism, cats with the disease could serve as modern-day equivalents of the caged canaries that once alerted coal miners to poisonous gas. While no link has yet been established between human hyperthyrodism and PBDE exposure, some ongoing studies do suggest such a connection.
Source: press release by the American Chemical Society. Read more
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First Published in 2007
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