Dog Ownership Associated With Longer Life

"The findings in these two well-done studies and analyses build upon prior studies and the conclusions of the 2013 AHA Scientific Statement 'Pet Ownership and Cardiovascular Risk' that dog ownership is associated with reductions in factors that contribute to cardiac risk and cardiovascular events," said Glenn N. Levine, M.D., chair of the writing group of the American Heart Association's scientific statement on pet ownership. "Further, these two studies provide good, quality data indicating dog ownership is associated with reduced cardiac and all-cause mortality. 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."

Research indicates that social isolation and lack of physical activity have negative impacts on human health. Both studies examined how dog ownership affected health outcomes. In the past, dog ownership has been indicated to alleviate social isolation, improve physical activity, and lower blood pressure; dog owners are thought to have better cardiovascular outcomes than those who are not.

Close to 182,000 people were reported to have had a heart attack of those 6% were dog owners; close to 155,000 people had an ischemic stroke of which 5% were dog owners in the study. Compared to nonowners dog ownership was associated with a 24% decreased risk of all cause mortality; 31% lower risk of death due to heart attack or stroke; 33% reduced risk of early heart survivors living alone; and a 27% reduced risk for early death for stroke survivors living alone. 

Reduced risk of death associated with dog ownership may be due to increased physical exercise and decreased loneliness/depression; both possible explanations have been connected to dog ownership in previous studies. Even though this study draws from a large sample possible misclassification of factors such as relationship status, change in ownership, or death of a dog could have affected the outcomes in this study.

"We know that social isolation is a strong risk factor for worse health outcomes and premature death. Previous studies have indicated that dog owners experience less social isolation and have more interaction with other people," said Tove Fall, D. V. M., professor at Uppsala University in Sweden. "Furthermore, keeping a dog is a good motivation for physical activity, which is an important factor in rehabilitation and mental health."

"The results of this study suggest positive effects of dog ownership for patients who have experienced a heart attack or stroke. However, more research is needed to confirm a causal relationship and giving recommendations about prescribing dogs for prevention. Moreover, from an animal welfare perspective, dogs should only be acquired by people who feel they have the capacity and knowledge to give the pet a good life."

In the systematic review and meta-analysis over 3.9 million participants from 10 separate studies were involved; 9 studies included comparison of all cause mortality outcomes for dog owners and non-owners, and 4 compared cardiovascular outcomes of non-owners and dog owners. Compared to non-owners dog owners had a 24% decreased risk of all cause mortality, 65% decreased risk of mortality after a heart attack, and a 31% decreased risk of mortality due to cardiovascular related problems. 

"Having a dog was associated with increased physical exercise, lower blood pressure levels and better cholesterol profile in previous reports," said Caroline Kramer, M.D. Ph.D., Assistant Professor of Medicine at the University of Toronto and an Endocrinologist and Clinician scientist at Leadership Sinai Centre for Diabetes at Mount Sinai Hospital, part of Sinai Health System. "As such, the findings that people who owned dogs lived longer and their risk for cardiovascular death was also lower are somewhat expected."

Studies included in the analysis included those in which participants were adults aged 18+, evaluated dog ownership at the start of the study, reported all cause or cardiovascular mortality, had original data from an original prospective study, were retrospective, and provided an absolute number of events that occurred and reported non-fatal cardiovascular events.

"Our findings suggest that having a dog is associated with longer life. Our analyses did not account for confounders such as better fitness or an overall healthier lifestyle that could be associated with dog ownership. The results, however, were very positive," said Dr. Kramer. "The next step on this topic would be an interventional study to evaluate cardiovascular outcomes after adopting a dog and the social and psychological benefits of dog ownership. As a dog owner myself, I can say that adopting Romeo (the author's miniature Schnauzer) has increased my steps and physical activity each day, and he has filled my daily routine with joy and unconditional love."