Pet Tags are Associated with Hyperthyroidism in Cats

by | Mar 23, 2021 | 2019, Environmental Health, Thyroid

Written by Joyce Smith, BS. This study provides evidence that exposure to TDCIPP present in homes may be associated with feline hyperthyroidism.

catFeline hyperthyroidism, first diagnosed in 1979, is the most common endocrine-related disease of older cats. Between 1980 and 2014, its prevalence has increased dramatically in the US from one in 200 to one in ten senior household cats. In North America, approximately two million cats have been diagnosed with hyperthyroidism 1. Feline hyperthyroidism, also known as toxic nodular goiter (TNG) in humans 1, may be an iodine insufficiency problem 2 or due to other known risk factors such as increasing age, using a litter box 3 and consuming canned dry cat food 4.

Coincidentally, during the mid 1970’s, flame retardants (FR), known as polybrominated diphenyl ethers (PBDEs) were first introduced 5. One of them, a tris(1,3-dichloroisopropyl)phosphate (TDCIPP) was initially applied to children’s sleepwear to meet US flammability standards in the mid-1970s 6 and discontinued from sleepwear in May 1977 because it was considered a mutagen 7. PBDEs were commonly used in textiles, polyurethane foam, plastics, and electronics 5. Due to adverse health effects, their phasing out in 2010 and a phased-in replacement with organophosphate ester (OPE) production began. 8. Both BPDEs 5 and OPEs 6 act as endocrine-disrupting chemicals (EDCs) that target the thyroid. While exposure to a portion of these is through inhalation in a gaseous state and through skin contact 9, FRs are bound to dust and ingested or inhaled by cats 10. However, TDCIPP use continued in other consumer products, particularly upholstered furniture containing polyurethane foam.

Anderson (lead researcher) and colleagues 11 suspecting an association between OPEs and hyperthyroidism in cats, recruited 78 mature, senior, and geriatric cats aged 7 years and older between December 2017 and October 2018 (39 hyperthyroid cats from the Animal Endocrine Clinic and OSU’s Animal Teaching Hospital and 39 non-hyperthyroid cats from the New York Cat Hospital and OSU’s Animal Teaching Hospital). The cats wore feline pet silicone name tags for 7 days (silicone adsorbs volatile and semi-volatile organic compounds).

Comparison of flame retardant exposures using silicone pet tags generated the following results:

  • TDCIPP that was present in over 90 % of tags while OPEs were found in only one silicone tag.
  • TDCIPP concentration was higher in pet tags of hyperthyroid cats compared to the tags of thyroid disease-free cats (P<0.07).
  • TDCIPP concentrations were also positively associated with fT4 (p<0.002), TT4 (p<0.01), and TT3 (p<0.10) concentrations among non-hyperthyroid cats.
  • TDCIPP exposures were 61% higher in homes using air fresheners compared to homes with no air freshener use (P<0.002) ;
  • TDCIPP exposures were higher in houses built since 2005 and more prevalent in cats that prefer to nap on upholstered furniture.
  • TDCIPP levels were higher in residences built since 2005 compared to those built prior to 1989 (p<0.002) and higher in residences containing upholstered furniture purchased between 2007 and 2012 compared to purchases prior to 2006 (p<0.01).
  • TDCIPP was also positively associated with consumption of commercial dry cat food (p<0.001) and cats who preferred to sleep on furniture compared to cats with no location preference (p<0.05).

The research team recommend that in future studies, silicone pet tags on cats can be useful when assessing the potential benefits of health interventions and also to detect future exposures of humans to endocrine disruptors such as flame retardants.

Source: Poutasse, Carolyn M., Julie B. Herbstman, Mark E. Peterson, Jana Gordon, Peter H. Soboroff, Darrell Holmes, Dezere Gonzalez, Lane G. Tidwell, and Kim A. Anderson. “Silicone pet tags associate tris (1, 3-dichloro-2-isopropyl) phosphate exposures with feline hyperthyroidism.” Environmental science & technology 53, no. 15 (2019): 9203-9213.

Posted March 23, 2021.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.

References:

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