Jessica Norrgran analysed if there is a link between polybrominated diphenylether (PBDE) levels in cat blood and feline hyperthyroidism (FH). PBDEs are brominated flameratardants (BFRs) that have been used as additives, that is they have not been chemically bonded into the products. Consequently, over time these chemicals migrate out of the flame-protected materials, for example from plastics, textiles, furniture, or electronics, and end up in house dust as the natural sink. Pet cats living indoors, lying down on the floor, and collecting dust in their fur will ingest these dust-enriched chemicals because of the their natural behaviour of licking when cleaning. Cats are for that reason highly exposed to PBDEs, more so than human adults.

This study aimed to identify the BFRs in cat serum, with a focus on hydroxylated metabolites of PBDE, to improve the understanding of feline metabolism of PBDEs. A pooled serum sample from 30 Swedish pet cats with FH was analysed, and brominated species were identified. Altogether 12 PBDE congeners were identified along with 5 PBDE metabolites and 2,4-dibromophenol, 2,4,6-, 2,4,5- and 2,3,4-tribromophenol. In addition, the finding of the fully brominated biphenyl, BB-209 at a high level was surprising since the source of this compound is unknown. The study could demonstrate that endocrine-disrupting chemicals were present in high concentrations in cat serum.


Norrgran J, Jones B, Lindquist NG, Bergman A. (2012). Decabromobiphenyl, polybrominated diphenyl ethers, and brominated phenolic compounds in serum of cats diagnosed with the endocrine disease feline hyperthyroidism. Arch Environ Contam Toxicol. Vol 63(1):161-8.