Study finds widespread PFAS exposure in dogs and cats
Bottom line
A new Frontiers in Veterinary Science study adds to the growing PFAS literature in companion animals, but with a cautionary finding for clinicians: in this retrospective analysis of serum from 179 dogs and 84 cats collected between 2021 and 2025, PFAS exposure was widespread, yet age, not endocrine disease status, was the main factor associated with PFAS concentrations after adjustment. The study included healthy controls alongside cats with hyperthyroidism and dogs with pituitary-dependent hypercortisolism, primary hyperparathyroidism, and adrenal tumors. PFOS was detected in nearly all animals, and PFOA and PFHxS were also common, with higher PFOS concentrations reported in dogs from Utrecht than in dogs from Bologna. (frontiersin.org)
Why it matters: For veterinary professionals, the takeaway isn't that PFAS can be ruled out as biologically relevant. It's that cross-sectional endocrine associations may be harder to interpret than expected, especially when older animals are overrepresented in disease cohorts. The authors found weak negative correlations between total PFAS and age in both species, and no independent association with disease status after age adjustment, underscoring the need for better-matched controls and longitudinal work before PFAS testing can inform endocrine case management. The broader veterinary literature still points to PFAS as a One Health concern, with prior reviews linking exposure in dogs and cats to changes in thyroid hormones, liver enzymes, cholesterol, and other biomarkers. (frontiersin.org)
What to watch: Watch for longitudinal studies, geographically diverse cohorts, and work that clarifies whether PFAS exposure is a marker of shared environment, a contributor to disease risk, or both. (frontiersin.org)
Key facts
- Study type
- Retrospective analysis
- Sample size
- 179 dogs, 84 cats
- Collection period
- 2021 to 2025
- Study sites
- Universities of Bologna and Utrecht
- Main finding
- After age adjustment, no PFAS were independently associated with endocrine disease status
- Key confounder
- Age, not endocrine disease status, was the main factor associated with PFAS concentrations
- Most common PFAS
- PFOS detected in 99.5% of dogs and 99.0% of cats
- Other common PFAS
- PFOA and PFHxS were also frequently detected
- Geographic finding
- Dogs from Utrecht had higher PFOS concentrations than dogs from Bologna
PFAS exposure appears to be common in both dogs and cats, but a new study suggests veterinarians should be careful about assuming a direct link to endocrine disease. In Frontiers in Veterinary Science, researchers reported detectable PFAS in serum from most of the 263 companion animals studied, yet after adjusting for age, they found no PFAS independently associated with endocrine disease status in either species. (frontiersin.org)
That finding lands in a research area that has drawn steady interest because PFAS are persistent environmental contaminants with known endocrine-disrupting potential in people, and companion animals share many of the same indoor and dietary exposures. Prior veterinary and comparative medicine reviews have framed dogs and cats as useful sentinels for household chemical exposure, while also noting that evidence tying PFAS to specific clinical outcomes in pets remains limited and sometimes inconsistent. (pubmed.ncbi.nlm.nih.gov)
The new study was retrospective and drew on samples collected from 2021 through 2025 at the Universities of Bologna and Utrecht. It included 179 dogs and 84 cats: 23 healthy dogs, 35 healthy cats, 49 cats with hyperthyroidism, 64 dogs with pituitary-dependent hypercortisolism, 16 dogs with primary hyperparathyroidism, and 85 dogs with adrenal tumors. Investigators measured 11 PFAS using LC-MS/MS. Eight PFAS were detected in dogs and nine in cats, with PFOS detected in 99.5% of dogs and 99.0% of cats. In dogs, PFHxS and PFOA were also frequently detected, while in cats PFOA was found in 96.0% of samples. Dogs from Utrecht had higher PFOS concentrations than dogs from Bologna, suggesting geography or exposure source may matter. (frontiersin.org)
At first glance, some between-group differences appeared to support disease associations. Healthy cats showed higher PFAS concentrations than diseased cats, while some canine disease groups showed higher concentrations for certain compounds. But those signals weakened when age was accounted for. Diseased animals were older than healthy controls, and the study found weak negative correlations between summed PFAS concentrations and age in both dogs and cats. No significant association was found with body condition score. The authors concluded that age substantially contributed to the apparent between-group differences and called for longitudinal studies with minimally exposed control populations. (frontiersin.org)
Industry and academic commentary around PFAS in animals has generally emphasized two points that help frame these results. First, exposure is not in doubt: prior reviews describe PFAS detection in serum, liver, kidneys, milk, fur, and household-linked matrices across animal species. Second, clinical interpretation is still immature. Reviews in veterinary and comparative medicine have argued that pets may function as sentinels for shared human-animal exposure, but they also caution that most mechanistic and epidemiologic evidence still comes from human or laboratory animal research rather than robust prospective studies in clinical veterinary populations. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For practicing veterinarians, this is a useful corrective. The study doesn't minimize PFAS as an environmental health issue; instead, it highlights how easily retrospective endocrine datasets can be confounded by age and cohort differences. That's especially relevant in disorders like feline hyperthyroidism and canine hypercortisolism, where affected animals are often older to begin with. For clinicians fielding questions from pet parents about "forever chemicals," the evidence supports acknowledging widespread exposure and potential biologic relevance, while also being clear that routine PFAS measurement is not yet ready to guide endocrine diagnosis or treatment decisions. (frontiersin.org)
The paper also reinforces the One Health dimension of companion animal toxicology. Because dogs and cats share homes, dust, water, and diet with people, geographic differences like the higher PFOS levels seen in the Utrecht cohort may eventually help identify local exposure pathways or regulatory effects. That could matter not only for veterinary case interpretation, but also for public health surveillance and client counseling when household contamination is suspected. This is an inference from the study's geographic signal and the broader sentinel-animal literature, rather than a direct conclusion of the paper. (frontiersin.org)
What to watch: The next important step is prospective work, ideally with age-matched controls, repeated sampling over time, and better characterization of diet, water, and household exposures. If those studies show consistent links between specific PFAS profiles and endocrine outcomes, veterinarians may eventually have a clearer role in exposure assessment, risk communication, and possibly prevention. For now, this study moves the field forward mainly by narrowing the claim: PFAS are common in dogs and cats, but this dataset doesn't show an age-independent association with endocrine disease. (frontiersin.org)