Living with a pet may battle cognitive decline, study says

CNN
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People over 50 living alone may be able to counter decline in their verbal cognition by adding a pet to their home, according to a new study. Losing the ability to easily find words and understand others are early signs of dementia, research has found.

“Pet ownership may completely offset the effect of living alone on cognitive decline,” said study coauthor Dr. Ciyong Lu, professor of epidemiology and medical science and associate dean of the School of Public Health at Sun Yat-sen University in Guangzhou, China.

However, the study could only show an association, not direct cause and effect, said neurologist Dr. Richard Isaacson, director of research at the Institute for Neurodegenerative Diseases in Florida. He was not involved in the study.

“It’s more accurate to say MAY slow down (cognitive decline) and that more prospective studies including a randomized controlled trial would be needed to make more definitive conclusions,” Isaacson said in an email.

“One caution I would say is that if a person who lives alone already has cognitive impairment, or physical limitations such as balance or vision problems, it wouldn’t generally be advisable for that person to adopt a pet to slow down their brain aging,” he added.

Caring for a pet, especially a puppy or kitten, is a lot of work for anyone, Isaacson said.

“Having cognitive decline makes it harder to responsibly care for a pet without help, and the person may be at higher risk of falling if they have trouble with balance or vision at baseline when walking and playing,” he said.

Living alone has been linked to increased anxiety and depression, especially if it follows the death of or divorce or separation from a partner, according to studies. A 2022 study found living alone, compared to living with others, increased the risk of depression by 42%. Depression, in turn, can double the risk of developing dementia, scientists have discovered; a 2020 commission named late-life depression as one of 12 major risk factors for dementia.

The study, published Tuesday in the journal JAMA Network Open, analyzed data from people age 50 and older participating in the English Longitudinal Study of Ageing who lived with pets. Researchers analyzed answers to an abbreviated word test about animals which “assesses the person’s ability to pay attention to the words, encode the words, and recall them later,” Isaacson said.

Pet ownership was associated with slower rates of decline in an overall score of verbal cognition, verbal memory and fluency if a person lived alone, but not if they lived with other people. The reason for that is unclear, Lu said.

“This test evaluates elements of attention, working memory, and short-term memory, for example,” he said. “While the results were statistically significant, the magnitude of the effects were not large for verbal memory — one half of a word (point) for the 20-point verbal memory task.”

However, there was a one word, or point, difference for verbal fluency, which was more significant, Isaacson said, between people living with only pet companionship compared to people living alone.

While more research needs to be done, there are a number of reasons having a pet such as a dog, cat, fish, bird or the like may reduce the risk of cognitive decline, Lu said.

“First, the companionship provided by pets can reduce loneliness and increase well-being,” Lu said, adding that “watching pets can help people calm, relax, and relieve stress and anxiety.”

In addition, pets can provide owners with opportunities to meet new people and have conversations and while taking walks, such as with a dog, Lu said. In fact, pet owners had a lower social isolation score than non-pet owners, according to the study.

Good quality sleep can play a key role as well. A 2023 study found each percentage decrease in slow-wave sleep per year was linked with a 27% increased risk of developing dementia and a 32% higher risk of Alzheimer’s disease.

“Pet owners fall asleep more easily than non-pet owners. For example, dog owners often walk their dogs before bedtime, which may have a relaxing effect on the owners and make it easier for them to fall asleep,” Lu said.

Some pets require specialized food, habitat and veterinary care, which can provide a sense of meaning and purpose for their owners, Lu said. In addition, by feeding and grooming a pet, owners also engage in more physical activity, often in nature. Some studies have found that communing with nature can boost the immune system, promoting better heath.

“Compared with non-pet owners, pet owners take more moderate and vigorous physical activity,” Lu said. In addition some pet enclosures such as aquariums or chicken coops may need specific lighting, water features, plants, rocks, or soils, that “may help promote owners to establish connections with nature, thereby increasing the immunity of owners,” Lu said.