Multiple chronic diseases compound to shorten dogs' lifespans, study finds

As dogs age, it's rare for them to develop just 1 chronic condition at a time—and new research suggests that's exactly the problem. Dogs carrying 5 or more diagnosed chronic diseases were more than twice as likely to die in any given year as dogs with a single condition, according to a study published in GeroScience,¹ regardless of the dog's age or size.

The findings, drawn from data on more than 50,000 dogs enrolled in the Dog Aging Project, indicate that chronic diseases in dogs don't simply accumulate independently with age. In some cases, combinations of diseases appear to have effects on survival that are greater than those of individual conditions, a pattern also observed in human medicine.^1,2

"Multimorbidity refers to the fact that individuals often become ill with more than 1 chronic disease at the same time," Kate E. Creevy, DVM, MS, DACVIM (SAIM), chief veterinary officer for the Dog Aging Project and a professor in the Department of Small Animal Clinical Sciences at Texas A&M College of Veterinary Medicine and Biomedical Sciences, said in a release announcing the findings.² "We know in people that being sick with more than 1 thing is frequently more damaging to health and survival than simply adding up the effects of 2 different diseases. We wanted to understand if the same thing is true for dogs."

How diseases compound each other

Researchers compared the health histories of dogs that died during the study period with those of still-living dogs, adjusting for age and enrollment duration. Chronic conditions in dogs tend to cluster and interact rather than accumulate in isolation, a cycle familiar to any clinician managing an older patient. Osteoarthritis, for example, can reduce activity level, contributing to weight gain, which in turn raises osteoarthritis risk further.²

Cancer and osteoarthritis were among the disease combinations associated with shorter lifespans. Dental disease frequently co-occurred with other chronic illnesses, and hearing loss showed up regularly in dogs carrying multiple diagnoses. Excess body weight played a dual role, the authors noted, both a contributor to chronic disease and a consequence of it.²

"Cancer can affect multiple body systems as it spreads," Creevy said. "Similarly, osteoarthritis can interfere with the activities of daily living. If a dog can't move comfortably, it may exercise less, drink less water, or have difficulty getting outside, and those consequences can lead to additional health problems."

Quantifying—and acting on—the risk

"We are all eventually going to die, but this analysis asked the question: For any given year of life, how likely is the dog to die this year?" Creevy said. "Dogs with 5 or more conditions were more than twice as likely to die [as] dogs with a single condition reported. It shows that the magnitude of this impact is pretty dramatic."

For practicing veterinarians, the findings underscore the potential value of considering multimorbidity as a whole rather than treating each diagnosis in isolation. Identifying which combinations of conditions carry the greatest added risk could eventually help clinicians and owners triage care, underscoring preventive measures familiar to most practices, including weight management, regular activity, and dental health.²

A compressed model for human aging

Because dogs typically live 10 to 12 years, researchers can observe an entire aging trajectory in roughly a decade, whereas similar longitudinal questions in humans can require following participants for 70 years or longer, which is part of why the Dog Aging Project has drawn interest as a translational model for human aging research.^1,2

"The reason we can learn this is because so many dedicated volunteer owners have shared their data with the Dog Aging Project," Creevy said. "Their willingness to tell us what happens to their dogs over several years is what makes this kind of research possible."

The study was funded by the National Institute on Aging, part of the National Institutes of Health, along with the Glenn Foundation for Medical Research and the WoodNext Foundation. The authors reported no competing interests.¹

References

1. Foreman ER, Corlin L, Creevy KE, Hoffman JM; Dog Aging Project Consortium. multimorbidity as a predictor of mortality in companion dogs. Geroscience. Published online June 1, 2026. doi:10.1007/s11357-026-02342-4
2. Haines C. Texas A&M study reveals how multiple chronic diseases shorten canine lifespan. News release. Texas A&M University College of Veterinary Medicine & Biomedical Sciences. August 25, 2026. Accessed September 2, 2026. https://vetmed.tamu.edu/news/press-releases/multiple-chronic-diseases-canine-lifespan/