Maddie's Pet Project

Want your dog to live longer? Studies give hints

By Mark Robison

Mark Robison

A pair of recent peer-reviewed studies confirm common opinions about why some dogs live longer: Being slimmer is healthier, getting spayed or neutered helps, mixed breeds live a bit longer than purebreds, and dental cleanings are worth considering.

What makes the studies especially interesting, though, is that they quantify just how much longer certain actions or circumstances add to life.

The first study looks at being overweight on the life expectancy of 12 dog breeds, based on the records of more than 59,000 dogs seen at the Banfield Hospital chain across North America. It was published in the May/June 2019 issue of the Journal of Veterinary Internal Medicine.

Being overweight takes a serious toll on a dog. For example, research found that a male Chihuahua of normal weight lives about 16.0 years while one who is overweight lives 13.9 years – meaning your Chihuahua would be expected to be with you for just over two years longer if his weight is under control.

The benefit of not being overweight is less pronounced but still significant as dogs get larger in size. A female golden retriever of normal weight would be expected to live about 13.5 years while, if overweight, would live about 10 months less.

The blog Companion Animal Psychology, which tipped me to the studies, notes that most pet owners are poor judges of whether their own animals are overweight. It recommends asking your vet to assess your pet’s weight and, if called for, to ask about ideas for shedding pounds. Some strategies that seem to work at our house are no free-feeding, portion control, only one or two snacks a day, and regular exercise.

The second study – published in the May/June 2019 Journal of the American Animal Hospital Association – included more than 2.3 million cats and dogs seen at Banfield Hospitals between 2010 and 2012 and focused on about 180,000 of those who died during that time frame.

Spaying and neutering pets is often recommended as a way to decrease the numbers of unwanted animals in shelters, and an added benefit is that they will likely be with you longer. The study found that a spayed dog will live an average of 14.35 years whereas an intact female dog will live 13.77 years – about 7 months’ difference. In dog years, that’s big.

For male dogs, there was still a benefit in getting neutered but it was much smaller – only about 3 weeks’ longer life.

One of this study’s most striking findings involved dental cleanings. “When comparing two dogs, all other factors being equal, a difference of one dental cleaning per year is associated with a nearly 20% decreased risk for death,” the researchers wrote.

But it’s not as significant as it may seem. “This finding,” the researchers added, “cannot be interpreted as indicating that dental scaling directly increases lifespan in dogs because of the observational nature of the study design. Indeed, dental scaling may be in whole or in part a surrogate indicator for some other factor such as general degree of veterinary (or owner) care dogs receive, owner attachment, or dog health status.”

Still, dental health is important. Without it, bacteria have more opportunity to attack the body. Among my dogs, who all received dental cleanings once or twice in their later years, it seems to add extra months of overall good health.

And for all you mutt lovers, the researchers found mixed-breed dogs outlive purebreds – 14.45 years on average vs. 14.14 years. That’s about four months.

I always enjoy when researchers mention things they thought were obvious but that turn out not to be true. In this particular study, they’d thought that visiting a veterinarian more often would correlate with a longer lifespan because disease would be caught and treated sooner. Instead, they found the opposite to be true and realized that, like with humans, dogs near the end of life tend to visit the doctor more.

Bottom line: If you’re thinking of getting a new dog, these studies offer some findings worth keeping in mind – on average, smaller dogs live longer than bigger ones; mixed breeds live a bit longer than purebreds, as do dogs who are spayed or neutered; and being overweight is strongly correlated with a shorter lifespan.

Mark Robison lives outside Reno and is co-executive director of Maddie's Pet Project in Nevada. Reach him at