Mapping disease patterns in dogs can reveal what's ahead

In a new analysis from the Dog Aging Project, researchers have built the first large-scale comorbidity map for companion dogs using owner-reported health histories from 26,614 pets across the United States.

The result is a network that highlights which illnesses tend to cluster and, when timing is available, which ones usually come first.

The goal is practical. If certain conditions line up in a common sequence, veterinarians can screen earlier, counsel dog owners more clearly, and manage risks with fewer blind spots.

Studying dogs and diseases

Pet dogs share our homes, daily environments, and many age-related illnesses, which makes them strong models for understanding how multiple diseases stack up over time in real-life settings.

Dogs often receive consistent veterinary care, so their medical records can reveal surprisingly insightful patterns.

The comorbidity study was led by Antoinette Fang of the University of Chicago, with colleagues from Fred Hutchinson Cancer Center, Texas A&M University, and Tufts University.

“Because pet dogs share our homes, environments and many of our age-related diseases, mapping how their illnesses cluster and cascade offers a powerful window into the same multimorbidity processes that erode human health and points to earlier detection and prevention strategies for people too,” said Fang.

What the dog disease map reveals

The team constructed an undirected comorbidity network that flags statistically significant condition pairings after adjusting for age, sex and reproductive status, weight, and mixed-breed versus purebred status.

Connections involving otitis externa – a condition marked by inflammation of the outer ear canal – reflect a familiar reality: allergies are a frequent underlying cause of ear problems and infections in dogs.

The network also linked proteinuria – an excess of protein in the urine – to anemia in the setting of chronic kidney disease. This connection is consistent with the biology of kidney-driven anemia in dogs.

The analysis highlights associations such as protein in the urine alongside low red blood cell counts, which may signal more advanced kidney disease. This connection demonstrates the importance of monitoring red blood cell production early.

A parasite cluster pattern was also found in the data, which aligns with clinical experience that many parasitic infections co-occur in the same animal.

Why timing matters

To examine the sequence in which conditions arise, the team incorporated reported onset dates and built a directed network to estimate which condition is more likely to precede another within a 12-month period.

This guide becomes useful when a dog shows an early sign and a clinician needs to decide what to check next.

One example stands out from everyday ophthalmology. In dogs, diabetes is strongly associated with cataracts, and about 75 percent of diabetic dogs develop blinding cataracts within two years of diagnosis. This pattern aligns with the network’s diabetes-before-cataracts signal.

The network also places keratoconjunctivitis sicca – commonly known as dry eye, where inadequate tear production leaves the eye unprotected – before corneal ulceration, a painful condition in which the cornea develops open sores.

This sequence aligns with the way insufficient tears can leave the cornea vulnerable to injury and infection.

A cardiovascular example points the same direction. The ordered map shows hypertension preceding chronic kidney disease in older dogs, which matches consensus guidance that sustained high blood pressure damages target organs, including the kidneys.

Dog diseases change with age

As dogs age, disease webs change shape, with more connections concentrating around a smaller set of hubs in senior dogs according to the authors’ age-stratified analyses.

The shift lines up with what many owners see, a long stretch of minor problems, then a steeper cascade later in life.

Body size complicates this picture in useful ways. In Dog Aging Project data, larger dogs carry higher lifetime prevalence for several categories like orthopedic, endocrine, and cancer, while smaller dogs show higher prevalence in some eye and cardiac categories, patterns that can shape size-aware screening choices.

A veterinarian who knows a patient’s size risks can use this network as a clinical overlay rather than a one size fits all checklist.

How vets can use the map

For primary care, the value is anticipatory. If a dog presents with a new diagnosis that sits at the center of a cluster, a vet can plan targeted tests, schedule follow-up at tighter intervals, and talk with owners about what to watch for.

The lesson for owners is to share detailed histories. Reporting onset dates, even approximately, helps transform a static problem list into a timeline that can guide critical decisions.

“Mining owner-reported data from the Dog Aging Project, we built the first large-scale canine comorbidity network, confirming that diabetes often occurs before cataracts and revealing that health problems tend to cluster around a few key diseases as dogs age,” said Fang.

Such a map can guide practical clinical trials, refine breed- and size-specific screening guidelines, and improve how veterinarians and owners discuss health risks well before they escalate into a crisis.

The study is published in the journal PLOS Computational Biology.

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