Hyperthyroidism, which leads to weight loss and heart problems, was not seen in US cats until 1979 but is now a leading cause of death.
Its discovery and subsequent spread coincides with the introduction of household materials impregnated with polybrominated diphenyl ethers (PBDEs).
The study, led by Janice Dye of the Environmental Protection Agency, only looked at 23 cats and did not find a direct statistically significant link between PBDE burden and hyperthyroidism. But the results show a striking rise in PBDE levels with increasing age and slightly higher levels in most hyperthyroid cats.
Concentrations in the older cats were 20 to 100 times higher than in adult humans in the US, but average levels among the younger animals were similar to those recorded in children.
This suggests that ingesting household dust – a major exposure route for toddlers – may also be a problem for cats, which consume the dust while grooming (ENDS Report 380, p 25 
). High levels of PBDEs were also found in tinned cat foods.
Household dust and blood samples from the UK show much lower levels of PBDE than North American samples.
