That last item comes courtesy of a new study published in Circulation, the journal of the American Heart Association, which reviews several decades’ of evidence on the relationship between dog ownership and mortality.
The authors undertook the review in an effort to reconcile differences in previously published literature on the topic, some of which showed a benefit to dog ownership; others which did not.
After reviewing 10 studies which included data on 3.8 million participants, the authors determined that “dog ownership was associated with a 24% risk reduction for all-cause mortality as compared to non-ownership”. The data showed even greater benefits among those who’d experienced cardiovascular issues, such as a heart attack and stroke.
“Dog ownership is associated with lower risk of death over the long term, which is possibly driven by a reduction in cardiovascular mortality,” the authors concluded.
So what exactly is it about owning a dog that would make people live longer? In an accompanying editorial, cardiologist Dhruv Kazi of Beth Israel Deaconess Medical Centre outlined some of the findings.
For starters, there are well-documented mental health benefits to owning a pooch: “Dogs offer companionship, reduce anxiety and loneliness, increase self-esteem, and improve overall mood,” Kazi writes.
The 2018 General Social Survey, for instance, found that dog owners were happier than cat owners. Then there are the physical benefits.
“Several studies have shown that acquiring a dog perforce increases physical exercise (as anyone who has unsuccessfully tried to sleep past the time of a dog’s routine morning walk can attest),” Kazi writes.
People who own dogs tend to spend more time outdoors, which is known to be beneficial to health. Simply petting a dog – especially a familiar one – lowers a person’s blood pressure.
It’s plausible that such physical and mental health benefits are the pathway by which dog ownership makes a person live longer. One drawback in the literature, however, is that there haven’t been any randomised controlled trials looking at dog ownership and mortality.
Researchers haven’t done many studies, for instance, that direct one group of people to purchase a dog, and another group to remain petless, and track their health over a period of time.
Studies of those types are considered the gold standard of evidence, what you’d need to be able to say definitively that owning a dog causes people to live longer. You’d want to do this to rule out confounding factors.
“Pet owners tend to be younger, wealthier, better educated, and more likely to be married, all of which improve cardiovascular outcomes,” Kazi writes.
It may be the case that being healthier and wealthier causes people to be more likely to acquire a dog. Still, Kazi writes, the balance of the evidence to date convinces him that “the association between dog ownership and improved survival is real, and is likely at least partially causal.”
One of the larger studies included in the review, controlled for a variety of socio-economic and demographic factors, found that the longevity effect of dog ownership remained.
“The most salient benefits of dog ownership on cardiovascular outcomes are likely mediated through large and sustained improvements in mental health… “ writes Kazi.
Although the study didn’t examine the effects of cat ownership on mortality, at least one previous paper has explored the connection and found that cat ownership, also, is linked to a decrease in fatal cardiovascular events.
That suggests that if you’re really serious about living a long life, you should get a dog and a cat to cover all your bases.