An analysis of data from a longitudinal study of older adults revealed that cat and dog owners tend to experience slower cognitive decline than non-owners. This difference persisted even after controlling for age and health conditions. Among dog owners, cognitive decline was slower in individuals who walked their dogs. The study was published in Scientific Reports.
As individuals age, their memory and cognitive functions decline. This decline occurs gradually at first, but as individuals enter advanced age, cognitive decline generally accelerates, even in the absence of dementia. However, this does not affect all older individuals equally. While some experience a sharp cognitive decline early on, others are able to maintain good cognitive capacities well into advanced age.
As life expectancy increases throughout the world, finding ways to slow or stop age-related cognitive decline is becoming an ever more important topic. Researchers have proposed various strategies to slow cognitive decline – treating sleep apnea, improving diet, increasing exercise and many others.
Interaction with pets might also be a viable strategy. Studies have shown that pets can serve as sources of social support. Interaction with them can lower stress indicators such as blood pressure, levels of the hormone cortisol, and heart rate.
Study author Erika Friedmann and her colleagues wanted to examine the relationship between pet ownership and changes in cognitive function of community-dwelling older adults over a period between 1 and 13 years. They wanted to see whether pet owners experience a slower deterioration of cognitive functions, whether it makes a difference if the pet is a cat or a dog, and whether dog walking might lead to slower cognitive decline.
They analyzed data from the Baltimore Longitudinal Study of Aging, the longest-running scientific study of human aging in the U.S., initiated in 1958. Researchers collect data from participants at regular intervals, with data collected every 4 years for younger participants and annually for those aged 80 or over. This data included results from a battery of cognitive tests conducted during these data collection visits.
This study utilized data from participants aged 50 and above who completed their first assessment of pet interaction and had at least two cognitive assessments in the dataset within ten years before March 2020. The data used included measures of pet ownership, assessments of cognitive function (such as the California Verbal Learning Test, the Benton Visual Retention Test, Digit Span test, Trail Making A and B tests, Digit Symbol Substitution Test, and the Boston naming test), and assessments of cognitive impairment (using the Mini Mental State Examination). The pet ownership measurements included various questions about pets, asking whether the participant owned a pet, what type of pet it was, and for how long they had owned it. Dog owners were also asked whether they walked their dogs.
Data from 637 participants were included in the study, with ages ranging from 51 to 101 years and an average age of 75 years. Of the participants, 54% were women, and 67% were White. 62% were married, 79% resided in single-family houses, and 84% had an annual income exceeding $50,000. 29% of participants owned pets, with 11% owning cats and 13% owning dogs. Among dog owners, 69% reported walking their dogs. At the study’s outset, pet ownership did not differ significantly between those who were cognitively intact and those who were not (i.e., those with dementia or cognitive impairment).
Results indicated that cognitive functions declined for all participants as they aged. However, this decline was slower in pet owners compared to non-owners. This decelerated decline was evident in some but not all cognitive tests used, suggesting that it may be related to specific cognitive functions. Additionally, the cognitive functions that deteriorated more slowly showed some variations between cat and dog owners.
Looking exclusively at dog owners, those who reported walking their dogs experienced slower cognitive decline compared to those who did not. All observed differences persisted even after researchers considered age and medical conditions.
“The current study provides important longitudinal evidence for the contribution of pet ownership to the maintenance of cognitive function in generally health community-residing older adults as they age,” the study authors concluded. “Older adult pet owners experienced less decline in cognitive function as they aged, after considering both their pre-existing health and age. Memory, executive function, language function, psychomotor speed, and processing speed deteriorated less over ten years among pet owners than among non-owners and among dog owners than non-owners. Cat owners experienced less deterioration in memory and language function. Dog walking also was associated with slower deterioration in cognitive function.”
The study makes an important contribution to the scientific understanding of factors related to cognitive decline. However, it also has limitations that need to be taken into account. Notably, the study design does not allow any cause-and-effect conclusions to be made. Additionally, the study sample was selected and consisted of individuals with better socio-economic status and with better cognitive functioning for their age compared to the general population.
The paper, “Pet ownership and maintenance of cognitive function in community‑residing older adults: evidence from the Baltimore Longitudinal Study of Aging (BLSA)”, was authored by Erika Friedmann, Nancy R.Gee, Eleanor M. Simonsick, Melissa H. Kitner‑Triolo, Barbara Resnick, Ikmat Adesanya, Lincy Koodaly, and Merve Gurlu.
