What are the risk factors for osteoarthritis in dogs?

22 January 2024

Osteoarthritis (OA) is the most common joint disorder in dogs and has a significant impact on the welfare and quality of life of affected dogs. Whilst OA is considered a disease of aging, the evidence for other potential risk factors for OA is limited and often conflicting.

A new study published in Frontiers in Veterinary Science has assessed specific risk factors (age, sex, body weight, breed, neuter status, and age at neutering) for diagnosis of OA in companion dogs¹.

The study used data from dogs seen at Banfield Pet Hospitals (primary care small animal hospitals) in the United States, with a date of death in 2019. The final cohort included 131,140 dogs, visiting from 1998 to 2019, of which 23.9% were diagnosed with OA during the study.

Age was confirmed as the strongest risk factor for OA diagnosis, and this was consistent across different breeds of different sizes.

Higher adult body weight was identified as a risk factor. Higher body condition scores (BCS) were also significantly associated with OA but this effect size was very small and not consistently significant in all breeds tested, and BCS was not a powerful predictor of OA diagnosis overall.

The impact of neutering on OA risk overall increased with body size, with a greater significant risk in medium and larger breed dogs (over 30 lbs) and a lesser risk in smaller breeds. Earlier neutering added to OA risk in both large and small dogs, and risk decreased progressively with delayed neutering up to 2 years of age. As neutering is a known risk factor for obesity, it’s possible that neutering increases OA risk by increasing the tendency for obesity.

The study found a small overall risk difference between male and female dogs, with male dogs at lower risk of developing OA, although the size of this effect in the overall cohort was small. This small risk difference between sexes suggests that OA diagnostic and preventative interventions should be targeted at male and female dogs equally.

Limitations of the research include the retrospective nature of the study and potential inaccuracies and misclassifications in the electronic health records, and although the sample size was large and expected to be representative of the patient population at the hospitals included in the study, the results might not be representative of the wider U.S. dog population.

Take home message

Overall, this study confirms the importance of several key risk factors for osteoarthritis in dogs, including older age, higher body weight, gonadectomy and younger age at gonadectomy. This information can assist veterinarians in identifying dogs at higher risk for OA, and an understanding of potentially modifiable risk factors, such as body condition and neutering, can inform preventative and treatment measures for dog owners.

References

¹Graves JL, McKenzie BA, Koch Z, Naka A, Spofford N & Morrison J (2023) Body weight, gonadectomy, and other risk factors for diagnosis of osteoarthritis in companion dogs. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2023.1275964

Resources

The BSAVA PetSavers Ageing Canine Toolkit helps vets and pet owners provide the best care for dogs as they age, including on common conditions associated with canine ageing like osteoarthritis. https://www.bsavalibrary.com/content/cil/cilgrouppetsaversact/petsavers-act-guide