Per‐ and polyfluoroalkyl substances in Northern California cats: Temporal comparison and a possible link to cat hyperthyroidism

• Published in: Environmental toxicology and chemistry 2018-10, Vol.37 (10), p.2523-2529
• Main Authors: Wang, Miaomiao, Guo, Weihong, Gardner, Steve, Petreas, Myrto, Park, June‐Soo
• Format: Article
• Language: English
• Subjects: Carboxylic acids; Cat hyperthyroidism; Cat serum; Cats; Diet; Dietary intake; Human serum; Hyperthyroidism; Indoor environments; Perfluoro compounds; Perfluorooctanoic acid; Per‐ and polyfluoroalkyl substances
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.4239

The indoor environment and dietary intake are considered to be major human exposure pathways to per‐ and polyfluoroalkyl substances (PFASs). Cats have similar exposures to humans by sharing their residential environments, although they have different diet, body sizes, and indoor activities. In the present study, we report PFAS levels in the serum of 2 groups of Northern California cats (>10 yr old) collected during 2 time periods: 2008 to 2010 (n = 21) and 2012 to 2013 (n = 22). Levels of ∑PFAS (geometric mean) were lower in the second period (geometric mean = 8.10 ng/mL) than the first time period (geometric mean = 15.8 ng/mL), although PFAS profiles remained similar. We also analyzed PFAS levels in human serum collected in the same time period (2008–2010) and geographic area, and compared the profiles and ∑PFAS levels (15.8 vs 14.3 ng/mL for cat and human, respectively). Long chain perfluorinated carboxylic acids, especially perfluorononanoic acid and perfluoroundecanoic acid, were significantly higher in cat serum than in humans. Furthermore, serum from hyperthyroid cats in the second time period showed higher ∑PFAS level (9.50 ng/mL) compared to nonhyperthyroid cats (7.24 ng/mL), and it is the perfluorooctanoic acid levels that were statistically significantly higher in hyperthyroid cats’ serum (p