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Cognitive decline was slower for older adults who had pets, an observational study showed.

Over 6 years, cognitive scores decreased at a slower rate in pet owners than in people without pets, reported Tiffany Braley, MD, MS, of the University of Michigan in Ann Arbor, and colleagues, in an abstract released in advance of the American Academy of Neurology annual meeting.

The magnitude of the association was larger among long-term pet owners, who had a cognitive composite score 1.2 points higher at 6 years than non-pet owners (P=0.03).

"Although this study cannot prove a cause and effect relationship between pet ownership and cognition, these findings provide early evidence to suggest that long-term pet ownership could be protective against cognitive decline, providing a novel and fundamental step to understanding how relationships with companion animals contribute to brain health," Braley told 麻豆传媒.

"Pet ownership should not be sought as a means to preserve cognitive health," Braley pointed out. "However, if a causal relationship exists between pet ownership and cognitive health, this would provide further support for programs to support older adults interested in maintaining or initiating pet ownership."

The findings were based on 1,369 people with a mean age of 65 in the longitudinal (HRS). Pet ownership and its duration were assessed in the 2012 wave, and people with impaired cognitive function at baseline were excluded.

The researchers used cognitive assessments from 2010 to 2016 to create a composite score derived from an immediate and delayed 10-noun free recall test, a serial seven subtraction test, and a backwards count test, with a total score range of 0-27.

Overall, 53% of participants owned pets and 32% were long-term pet owners, defined as owning a pet for 5 years or more. Most participants (88%) were white; 7% were Black and 2% were Hispanic.

The cognitive benefits associated with longer pet ownership were more prominent for people who were Black, college-educated, and men, Braley and colleagues noted.

Earlier studies have demonstrated that pet ownership can reduce loneliness and depression, both of which have been associated with cognitive changes. Military veterans with post-traumatic stress disorder (PTSD), for example, experienced significantly greater improvement in depression and loneliness scores after adopting a dog, observed Steven Stern, MD, of the University of Texas Health Science Center in San Antonio.

"When I started working in the PTSD clinic at the VA, I was struck by the fact that veterans with PTSD would frequently talk about their dogs and how much having a dog helped them," Stern told 麻豆传媒. That observation led to a small clinical trial that randomized veterans with PTSD to dog adoption from a local Humane Society and or a 3-month wait list. Within a month, most veterans who adopted a dog reported a positive experience of companionship with their pet, and many became more physically and socially active.

More recently, U.K. researchers showed that pets may help people with early dementia. "The was a unique opportunity to examine associations between pet ownership and walking, loneliness, depression, and quality of life in a large cohort of people with mild-to-moderate dementia," noted Carol Opdebeeck, PhD, of Manchester Metropolitan University in England.

"The key to any benefits of pet ownership in this study was in the person being involved in the care of their pet," Opdebeeck told 麻豆传媒. People who cared for a dog walked more and were less lonely, she said. "People who had a pet but were not involved in its care were more likely to be depressed and have poorer quality of life than people with no pet or those with a pet who were involved in its care," she added.

A limitation of the HRS study was that the length of pet ownership was assessed only at one time point. Unknown confounders also may have influenced results.

"We do not recommend pet ownership as a therapeutic intervention," co-author Jennifer Applebaum, MS, of the University of Florida in Gainesville, told 麻豆传媒. "However, we do recommend that people who own pets be supported in keeping them through public policy and community partnerships. An unwanted separation from a pet can be devastating, and marginalized populations are most at risk of these unwanted outcomes."

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