Dog owners may live longer lives and experience better cardiovascular outcomes, especially for heart attack and stroke survivors who live alone, according to two sister studies.
Previous research in this area has linked dog ownership to lower blood pressure and decreases in mental health issues like loneliness. In a 2013 scientific statement, the American Heart Association (AHA) concluded that, based on the growing body of evidence, “…dog ownership is probably associated with decreased cardiovascular risk.”
“These two studies provide good, quality data indicating dog ownership is associated with reduced cardiac and all-cause mortality,” commented Glenn Levine from the AHA to ScienceDaily. “While these non-randomized studies cannot ‘prove’ that adopting or owning a dog directly leads to reduced mortality, these robust findings are certainly at least suggestive of this.”
The studies, published in Circulation: Cardiovascular Quality and Outcomes, were a collaboration between Canadian and Swedish researchers.
Dogs likely improve mental and physical well being
In the first of two sister studies, researchers compared the health outcomes of dog owners versus non-owners using data sourced from the Swedish National Patient Register. All participants were residents of Sweden between 40-85 years old who had experienced either a heart or stroke during the study period (2001-2012). Across some 185,000 heart attack patients, around 6% were dog owners, while among 155,000 stroke patients, dog ownership was around 5%.
They found that, for heart attack patients who owned a dog, their mortality risk was lowered by 33% if they lived solo, and 15% if they lived with a partner or child. For the stroke patients who owned dogs, it was a 27% risk reduction for those who lived alone and 12% for those living with family.
No causal relationship was established by this study, but the authors have a few hunches as to why this effect may be happening. One possibility is the increase in physical activity that comes with the responsibility of having to walk one’s dog. Dog owners also have more opportunities to socialize and a lower risk of depression thanks to the companionship, and that may also explain the difference (depression can lead to physical health risks including heart attacks).
“Previous studies have indicated that dog owners experience less social isolation and have more interaction with other people. Furthermore, keeping a dog is a good motivation for physical activity, which is an important factor in rehabilitation and mental health.”
A limitation of the study concerns the nature of dog ownership among participants, especially with couples living together where the other partner may be the primary caretaker of the dog.
Lower mortality risk found, but don’t jump to conclusions
The second of the sister studies was a meta-analysis of 10 studies comprising a total study population of 3.8 million people. This study explored the question of whether dog ownership can lead to a longer life. Most of the studies under review investigated all-cause mortality, while some looked at cardiovascular outcomes.
The key stats from the review were that dog owners experienced a 24% lower risk of all-cause mortality, a 65% lower risk of mortality following a heart attack, and a 31% lower mortality risk due to cardiovascular-related issues. Similar to the first study and previous research, researchers found associations between dog ownership and lower blood pressure, more exercise, and healthier cholesterol profiles.
In a related commentary, the authors wrote that although the results are promising, we should not jump to the conclusion that increasing dog ownership will deliver widespread decreases in cardiovascular complications. They also noted that it’s important to remember that pet ownership is a serious commitment which should only be undertaken if there is a real prospect of a good life for the animal.
“Although a growing body of evidence now supports the idea that adopting a dog enhances the mental and physical well-being of its human companion, the real reward of dog ownership, in the words of Pulitzer Prize–winning poet Mary Oliver, is that there can hardly be a ‘sweeter arrangement’ than the unconditional love of a loyal friend,” say the authors.
“The health benefits of dog ownership are a welcome and possibly substantial bonus.”