Canine pals could be key to longevity

As most dog owners will attest, four-legged canine companions generate boundless love and joy through their playful antics and tail-wagging devotion.

Accordingly, much research finds they can improve mental health – and now, evidence for their tangible physical health benefits is growing.

A Swedish study and separate meta-analysis, published in the journal Circulation, found that dog owners live longer and do better after having a heart attack or stroke.

First, the Swedes compared the health outcomes of 182,000 people with and without dogs after a heart attack and 155,000 people after a stroke, using health data recorded by the Swedish National Patient Register between 2001 and 2012.

The largest differences between dog owners and non-owners were seen in single households.

After adjusting for demographic and socioeconomic factors, they found that dog owners who lived alone had 33% lower risk of death after a heart attack and 27% less chance of death after a stroke. The effect was not quite as pronounced for people living with a partner or child, with 15% and 12% lower risk, respectively.

Although the mechanisms can’t be confirmed with the observational study design, senior author Tove Fall from Uppsala University in Sweden says he was surprised at the large differences in the outcomes, and thinks it’s likely that exercise and companionship factor in.

“We know that dogs can be a good motivator for physical activity,” he says. “We also know that physical activity and social support are important for optimal recovery after a major cardiovascular event.”

Meanwhile, clinician and research scientist Caroline Kramer, from Mt Sinai Hospital in Toronto, Canada, was curious about research showing the benefits of dog ownership in her pursuit of lifestyle changes that can promote people’s health.

What really sparked it, she admits, was her dog – a miniature Schnauzer called Romeo.

“Since I adopted him,” she says, “I got more active, and the daily routine with a dog companion is a joy. So when I saw a research report on that I was curious and decided to research further.”

The result was a systematic review and meta-analysis of the association between dog ownership and death from all causes or heart disease.

The composite analysis included 10 studies with data from 3.8 million patients and follow-ups ranging from one to 22 years. Overall, having a dog prolonged survival, reducing risk of death by 24%.

When it came to heart attacks and other heart-related issues, dog owners had a 65% and 31% lower risk of death, respectively.

The research builds upon prior findings and conclusions of the American Heart Association (AHA)’s scientific statement that dog ownership is associated with lower risk factors for heart disease, such as high blood pressure and blood lipid levels, says Glenn Levine, chair of the statement’s writing group.

“Further, these two studies provide good, quality data indicating dog ownership is associated with reduced cardiac and all-cause mortality,” he adds.

“While these non-randomised controlled studies cannot ‘prove’ that adopting or owning a dog directly leads to reduced mortality, those robust findings are certainly at least suggestive of this.”

In a related editorial, “Who is rescuing whom?”, Dhruv Kazi, from Harvard Medical School, Boston, notes that pet owners tend to have other heart-health promoting features. These include being younger, better educated, wealthier and more likely to be married. It’s also possible that healthier people are more able to adopt a dog.

However, he remarks that it’s plausible they improve people’s health, given that dog ownership prompts more time being active outdoors. He also notes evidence that the rich variety of germs they bring into the home can positively alter people’s gut microbiome.

He agrees with the AHA, though, that medical reasons alone should not the driving motivator to get a dog, as it’s “a much larger undertaking than embarking on a new medical therapy”, involving significant commitment and lifestyle changes.

Quoting Pulitzer-Prize winning poet Mary Oliver, he concludes that “the real reward of dog ownership … is that there can hardly be a ‘sweeter arrangement’ than the unconditional love of a loyal friend.

“The health benefits of dog ownership are a welcome and possibly substantial bonus.”