Key points:
- A new study found larger dogs are more likely to face certain types of health conditions than smaller dogs.
- The study does not confirm a causal relationship between dog size, age, and disease.
- The results do provide insights into disease categories and suggest future research based on age and size patterns associated with specific conditions.
A study of more than 25,000 U.S. dogs and 238 breeds has linked dog size to varying patterns of risk for health conditions over the course of a dog’s lifespan.
On average, smaller dogs tend to live longer than larger dogs. Evidence suggests that larger dogs do not have more health conditions, but that dogs of different sizes may face different levels of risk for different conditions.
To deepen understanding of this phenomenon, Yunbi Nam and colleagues at the University of Washington analyzed survey data on 27,541 dogs representing 238 breeds, as reported by dog owners participating in the ongoing Dog Aging Project.
According to the study results, published in PLOS One, larger dogs were more likely to have faced certain types of health conditions at some point in their lives, including cancer, bone-related disease, gastrointestinal problems, ear/nose/throat issues, neurological and endocrine conditions, and infectious diseases. Meanwhile, smaller dogs were more likely to have experienced ocular, cardiac, liver/pancreas and respiratory diseases. History of kidney/urinary disease did not differ significantly for larger versus smaller dogs.
For many types of conditions—including cancer, ocular, cardiac, orthopedic, and ear/nose/throat conditions—different dog sizes were associated with differing patterns of risk over the course of a dog’s lifespan.
The results held up even after the researchers statistically accounted for the dogs’ sex, where they lived, and whether they were purebred or mixed-breed.
The researchers note that this study does not confirm any causal relationship between dog size, age, and disease. Still, the findings could help lead to deeper understanding of the types of conditions that may underlie the lower lifespan of larger dogs. For instance, within the disease categories explored in this study, future research could home in on age and size patterns associated with specific conditions.
“These results provide insights into the disease categories that may contribute to reduced lifespan in larger dogs and suggest multiple further avenues for further exploration,” the authors conclude.