A new study has found that, for older adults living alone, owning a pet was linked to slower rates of decline in some aspects of cognition and may completely offset the association between living alone, a recognized dementia risk, and cognitive decline.
The number of people living alone has increased in the past few decades. In 2021, it was 28.5% in the US, 29.4% in the UK and 25.6% in Australia. A recent meta-analysis found that, for older adults, social isolation is an important risk factor for dementia and was associated with a greater population risk than physical inactivity, hypertension, diabetes and obesity. Something that reduces social isolation is pet ownership.
There’s limited – and controversial – evidence on the link between raising pets and the rate of cognitive decline. Some say it improves aspects of cognitive functioning; others say it doesn’t. A new study by researchers at China’s Sun Yat-sen University investigated whether pet ownership is associated with cognitive decline in older adults who live alone and whether it mitigates that decline.
The researchers obtained data from the English Longitudinal Study of Ageing (ELSA), an ongoing, prospective, and nationally representative cohort of community-dwelling UK adults aged 50 or older. In wave five of the study, participants were asked, “Do you keep any household pets inside your house/flat?” and the researchers looked at data from 7,945 participants with a mean age of 66.3; 56% were women. Information relating to cognitive function was obtained from subsequent waves of the study, with the researchers looking particularly at verbal memory and verbal fluency.
Verbal memory is the ability to remember written or spoken information previously learned from a conversation, dialogue, or written work. It’s part of episodic memory, the memory of events or personal experiences used to enable a person to identify when and where an episode happened. Verbal fluency is the ease with which people can produce words, an indicator of memory retrieval and executive brain function.
After adjusting for potential covariants, the researchers found that, compared with non-pet owners, pet owners had a slower rate of decline in verbal memory and fluency. In contrast to older adults living with others, those living alone showed a faster decline in these two factors, as did non-pet owners living alone compared with pet owners living with other people.
“Older adults living alone are at high risk for developing dementia, and living alone is a state that is not easily changed,” the researchers said. “It is worth noting that compared with pet owners living with others, pet owners living alone did not show faster rates of decline in verbal memory or verbal fluency. These findings preliminarily suggest that pet ownership might completely offset the association of living alone with faster rates of decline in verbal memory and verbal fluency among older adults.”
The researchers note some of the study’s limitations. First, it only considered verbal memory and verbal fluency, representing episodic memory and executive function, respectively, whereas cognitive function includes many other dimensions, such as attention, reasoning, and processing speed and accuracy. Second, ELSA contained no information regarding the duration of pet ownership, and third, almost all study participants were white, making the results ungeneralizable to other racial and ethnic groups.
And because it was an observational study, the effect of unmeasured confounding factors, such as the APOE gene, which influences Alzheimer’s disease risk, on the results can’t be eliminated, hindering the determination of a causal association.
Further studies that include a comprehensive cognitive function assessment are needed to explore the association between pet ownership and global cognitive decline in those living alone.
The study was published in the journal JAMA Network.
Source: Sun Yat-sen University via Scimex
