The research, published in Evolution, Medicine & Public Health, surveyed the human parents of more than 21,000 dogs and found that social companionship — with both people and other animals — had the largest influence on healthier aging among dogs. The effect was five times greater than anything else they looked at, such as family finances, household children or the pet parent’s age.
Improving dog and human health
The study is part of the Dog Aging Project, a large community-science research effort started in 2018 and funded by the National Institute on Aging and private donations. It’s led by the University of Washington and Texas A&M schools of medicine and includes more than a dozen institutions, including Arizona State University.
Its goal is to learn how genes, lifestyle and the environment influence aging and disease among dogs. Researchers also hope the insights can help human health.
“Dogs are often considered our closest animal companions and share many aspects of our daily lives,” said Brianah McCoy, an ASU doctoral student and a co-author of the paper. “By studying how the social environment affects dog health, we can gain insights that may also be relevant to human health.”
More than 45,000 dogs overall are enrolled in the aging project. A subset, about 1,000 dogs, are part of a more focused cohort from whom Snyder-Mackler and his collaborators are collecting blood and other biological samples over many years to uncover additional clues.
Having furry friends is linked to better health
The researchers used statistical tools to analyze factors in the dogs’ social environments obtained from surveys completed by dog parents. The questionnaires asked about, among other things, physical activity, environment, dog behavior, diet, medications and preventive medications, health status and owner demographics.
The scientists narrowed their analysis to five key factors — neighborhood stability, total household income, social time with children, social time with animals and owner age — that together might explain how the social environment could affect a dog’s well-being.
They found poorer health among dogs who lived in households with financial difficulties and other stressors, and better health among dogs who experienced more social companionship, such as living with other dogs.
The researchers, however, did not quantify life span, although they plan to do so in the future. “While we can’t say ‘having another dog in the house adds X years to your dog’s life,’ we were able to compare the strengths of the effect of different environmental factors on health,” Snyder-Mackler said.
The researchers cautioned that the results don’t mean that pet parents need to add more dogs to the family or rush their pets to dog parks or doggy day-care.
“We don’t know if the environmental factors we measured caused the health outcomes, so we don’t want to make any strong statements about what owners should or shouldn’t do,” Snyder-Mackler said. “The study just looked at whether you had other animal companions in the house. But it does suggest that having more furry friends is linked to better health outcomes.”
Some dogs may not benefit from social interactions
Scientists not involved in the study pointed out that not all dogs respond similarly.
“Some dogs may find social interactions stressful,” said Clara Wilson, a postdoctoral researcher in the Penn Vet Working Dog Center at the University of Pennsylvania School of Veterinary Medicine, “and it may not be in the dog’s best interests to force these interactions.”
Courtney Sexton, an affiliate researcher in the anthropology department at George Washington University — and who contributes other research to the Dog Aging Project — said her dog would rather play with a ball than with other dogs, and it’s important for pet parents to pick up their pets’ cues.
Several findings were surprising, the study authors said.
- Having children in the household had a negative impact on a dog’s health.
- Dogs in wealthier households were diagnosed with more diseases than those in less affluent homes.
- Dogs seemed to be healthier when they lived with older humans, and this effect was stronger in younger dogs.
Children may be detrimental to the health of dogs because of resource allocation, the researchers suggested. “It’s not that kids hurt the dogs or directly affect their health,” said Layla Brassington, a doctoral student at Vanderbilt University, who worked on the study as a master’s student at Arizona State University. “The more children or time that owners dedicate to their children likely leads to less time and effort they can dedicate to their furry children.”
The authors theorize that wealthier households have better access to medical care, and pet parents might seek veterinary services more frequently, which leads to identifying more diseases.
The ages of the dogs also affected the findings, with younger dogs seeming to be “more tuned into the age of their owner and how it impacts their well-being,” McCoy said.
Could dogs benefit from a cat companion?
The researchers did not specifically look at the effect of breeds — they did not have enough detail on individual breeds — or exercise, Snyder-Mackler said. (The Dog Aging Project recently released a study that found physical activity is associated with a better cognitive outcome in dogs.) “What we did see was that the strength of the relationship between the environment and health was similar when we looked separately at mixed-breed versus purebred dogs,” he said.
They also acknowledged one study limitation — the sample consisted of mostly high-income dog parents. A more diverse set could help “unravel the true magnitude of certain variables’ influence on canine well-being,” McCoy said. “It is possible that the effects we found in this study would be even stronger if we had a more varied and inclusive population.”
Most of the pets in the multi-animal households were dogs, and the scientists said there was insufficient data to distinguish between the effects of having additional dogs vs. other species.
“It could be that having other pets — even cats — provides health benefits through companionship,” Snyder-Mackler said.
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