Environmental Causes Of Lymphoma

Hello Summarians!

Do we have biomarkers that can reliably estimate issues with frailty and healthspan? That seems to be the holy grail in all circles of medicine. From advanced testing, such as DNA analysis, to changes in lipid profiles, it would be beneficial to detect these changes early and easily. One of our studies discusses some possible markers in dogs.

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Metabolic Dysfunction In Dogs

This study explored age-related metabolic dysfunction in companion dogs and compared it with patterns known in humans and rodents. A diverse group of client-owned dogs was evaluated for multiple serum and plasma analytes, including insulin, glucose, cholesterol, IGF-1, adiponectin, liver enzymes, and fatty acids, to link these biomarkers to frailty and health-related quality of life. 

The findings showed that, similar to humans, aging dogs exhibited rising insulin levels, increases in circulating fatty acids, cholesterol, and liver enzymes (ALT, ALP), along with decreases in adiponectin. Importantly, these metabolic changes were associated with frailty and poorer quality of life. However, unlike humans and rodents, dogs demonstrated a decline rather than an increase in fasting glucose with age, suggesting species-specific differences in glucose regulation and the rarity of type 2 diabetes–like conditions in dogs. Elevated insulin levels were identified for the first time as correlating with frailty and quality of life, highlighting their potential clinical significance. 

Adiponectin, typically protective in humans, also declined in aged dogs and was linked to frailty, though associations with quality of life weakened when adjusting for covariates. Elevated cholesterol and fatty acids strengthened their association with frailty as dogs aged, mirroring the detrimental effects of dyslipidemia observed in humans. IGF-1, a well-known longevity factor across species, showed a strong relationship with body size in dogs, complicating its associations with aging markers. 

The study emphasizes that metabolic dysfunction in dogs shares many conserved features with other species, while also diverging in critical ways, particularly with respect to glucose dynamics. Subtle shifts in analytes like ALT and ALP, even within reference ranges, were also linked to frailty and quality of life, suggesting that conventional thresholds may underestimate their clinical relevance in aging. Together, the results support insulin, lipids, adiponectin, and liver enzymes as potential biomarkers of canine aging and healthspan, underscoring the need for further research to clarify causality and translational potential. 

McKenzie, B., Peloquin, M., Graves, J.L. et al. Changes in insulin, adiponectin and lipid concentrations with age are associated with frailty and reduced quality of life in dogs. Sci Rep 15, 5380 (2025). https://doi.org/10.1038/s41598-025-89923-z 

Bottom line — May be useful to determine biomarkers for aging and healthspan

Environmental Causes Of Lymphoma

Multicentric lymphoma (ML) in dogs shares many clinical features and geographic patterns with human non-Hodgkin lymphoma (NHL), which has been linked to exposures to volatile organic compounds such as benzene, 1,3-butadiene, and trichloroethylene, as well as herbicides including 2,4-D, glyphosate, and atrazine, and nitrate in water. Similar associations have been suggested in dogs, but studies to date have lacked direct biomonitoring. This study focused on boxer dogs, a breed predisposed to lymphoma, to determine whether urinary concentrations of these chemicals differed between ML cases and controls, and whether these exposures correlated with urbanicity or environmental samples from household water and indoor air.

All enrolled boxers had detectable urinary concentrations of 2,4-D, glyphosate, and atrazine. Levels of 2,4-D varied widely, and although concentrations tended to be higher in ML cases compared to controls, the difference did not reach statistical significance given the small sample size. Herbicides were not detected in household water, suggesting that exposures likely occurred from other sources such as indoor dust or even commercial dog food, and the variation in urinary concentrations may have reflected differences in timing of exposure relative to sample collection.

Benzene exposure was also widespread. While urinary levels of the major metabolite MUCA did not differ significantly between groups, ML cases showed higher concentrations when adjusted for urbanicity, although large variability limited conclusions. Importantly, urinary levels of another benzene metabolite, PHMA, were higher in ML cases in univariable analysis, consistent with human studies linking benzene to NHL. Indoor sources of benzene likely included gas stoves, attached garages, building materials, paints, and solvents. For 1,3-butadiene, urinary metabolite concentrations were much higher than those reported in prior studies of dogs, but no differences were observed between cases and controls, again with large variability across individuals.

 Braman SL, Peterson HM, Tindle AN, Elbe A, Mani E, Danielson C, Labadie J, Trepanier LA. Environmental Chemical Exposures in Boxer Dogs With Multicentric Lymphoma. J Vet Intern Med. 2025 Sep-Oct;39(5):e70230. doi: 10.1111/jvim.70230. PMID: 40874648; PMCID: PMC12392286.

Bottom line — Good information. Benzene is again highly suspect.

Arthritis Incidence In Dogs

This study investigated the prevalence and severity of osteoarthritis (OA) in dogs without a prior OA diagnosis undergoing anesthesia for dental procedures. The findings revealed a surprisingly high prevalence of radiographic OA, with most affected dogs showing subtle clinical signs that owners had not recognized. Approximately 83% of dogs with OA demonstrated some degree of lameness, though often mild, and pelvic limb joints—particularly the hips and tarsi—were most frequently affected. Hip OA was common, consistent with known associations with hip dysplasia, while forelimb OA was less common than expected compared to cadaveric data. Elbow OA was also relatively rare in this population. Importantly, multiple joint involvement was frequent, with the majority of arthritic dogs having more than one joint affected. 

Most radiographic changes were mild, yet even these likely indicated irreversible cartilage damage, underscoring the need for earlier identification and intervention. Objective gait analysis showed subtle but significant reductions in pelvic limb propulsion in affected dogs, while orthopedic exams often detected abnormalities despite minimal or absent visible lameness. Owner questionnaires revealed only modest recognition of mobility issues, suggesting that veterinarians must take the lead in screening for OA during wellness exams or when dogs are anesthetized for other procedures. 

Risk factors for OA included breed predisposition, larger body size, older age, and possibly early neutering. Although obesity is a recognized contributor, the study included few overweight dogs; however, all dogs weighed more than 11 kg, a factor itself associated with an increased risk. The study’s limitations included a small sample size, a restriction to middle-aged and older dogs over 11 kg, and the use of a non-validated questionnaire. Nevertheless, results strongly suggested that OA is both underdiagnosed and highly prevalent in dogs, particularly in the pelvic limbs, and that careful clinical and radiographic screening could identify cases earlier and help improve welfare by initiating treatment before end-stage disease develops. 

Millis, D. L., & Hecht, S. (2025). Osteoarthritis has a high prevalence in dogs undergoing routine dental prophylaxis. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.25.05.0330 

Bottom line — Underdiagnosed and highly prevalent in dogs.

Just putting things in perspective …