Aging in Dogs: From Genetic and Environmental Factors to a Preventive Approach to Comorbidities

The Dog Aging Project, a long-term biological study of aging in dogs, provides the first large-scale mapping of age-related comorbidities in dogs. Using data from 26,614 dogs with at least one of the 160 conditions listed, the authors establish links between diseases and project risk factors based on age, weight, sex, and reproductive status, as well as breed (pedigree dog versus mixed breed). The result is a true early-warning system for veterinarians, who can implement more effective treatments and preventive measures in cases of comorbidity (diabetes and cataracts or blindness, hypertension and chronic kidney disease, etc.) as well as monitoring risk factors to watch for (diabetes preceding cataracts, elbow or hip dysplasia preceding osteoarthritis, dry keratoconjunctivitis preceding corneal ulcers, etc.).  

From Population-Level Data to Individual Probabilities: How the Model Works

The Dog Aging Project database is derived from the Health and Life Experiences Survey (HLES), which tracks the prevalence of diseases throughout dogs’ lifetimes as well as their onset dates as reported by owners. The 160 conditions included are those observed in at least 60 dogs. For each disease, a multivariate logistic model estimates the probability that each animal will develop the condition based on its age, weight, sex, reproductive status, and breed. These individualized probabilities are then used in a comorbidity test based on the binomial Poisson distribution. Regarding the temporal approach, for dogs with comorbidities, the order of onset of the two diseases is compared over a 12-month period.  

Associations, Causal Links, and the Effect of Age

The study highlights co-occurrences already described in ophthalmology-endocrinology and nephrology-cardiology, but also less well-known associations, such as the link between proteinuria and anemia, offering avenues for preventing inflammation in chronic disease and detecting renal abnormalities that remain underdiagnosed. Depending on the dog’s life stage, comorbidities increase with age and peak in senior dogs. In fact, it is in this group that the association between hypertension and chronic kidney disease is most common, which confirms clinical experience in canine geriatrics.  

From Diagnosis to Proactive Monitoring

The initial diagnosis is a key step in the preventive approach. In a dog with diabetes, the diabetes-cataract interaction warrants close and scheduled ophthalmologic monitoring—even during the phase of glycemic control—to facilitate early detection of lens opacities and inflammatory complications. In the dysplasia-osteoarthritis progression, the benefits of early management combine weight control, a controlled activity plan, and the implementation of a rational analgesic regimen to slow the degenerative cascade. In cases of the dry keratoconjunctivitis-ulcer sequence, rigorous monitoring of tear tests and corneal protection takes on particular importance, especially in brachycephalic dogs. In senior dogs, the combination of hypertension and chronic kidney disease underscores the importance of systematic screening through blood pressure monitoring and urinalysis at defined intervals, even in animals that appear asymptomatic. These guidelines do not replace clinical judgment; rather, they prioritize screening and owner education on an individual basis, consistent with the patterns of observed disease associations.  

Guidelines for Clinical Practice and Care Management

These disease combinations transform an isolated clinical diagnosis into a long-term action plan, including, in particular, a schedule of health checkups to be performed, in order to better structure the course of care in canine geriatrics. At the level of the general canine population, this large-scale study sheds light on major advances in understanding the genetic and environmental risk factors for morbidity and mortality in dogs, by age group and body type, paving the way for health indicators ranging from cancer to cognitive function, and highlighting the new research opportunities offered by large-scale cohort studies in dogs. The methodology is reproducible and well-documented, and comprehensive tables of disease associations are made available to veterinarians for practical application in clinical practice.