Aging Dogs, Aging Owners

Aging is a challenge for dogs and their owners.

Source: S.McQuillan

Over the past several decades, research has greatly advanced our understanding of the nature and biology of aging in both humans and our canine companions, according to a review article published in the June 7, 2021 issue of Frontiers in Veterinary Science. As the researchers point out, the human-dog relationship often faces a variety of challenges as older human adults and their pets start to age.

In many ways, dogs and humans age in similar fashion, the researchers point out. We know much more about the ramifications of aging in humans than we do about aging in dogs, but research shows us that the different ways age affects the risk of dying is similar. For both humans and dogs, the risk of dying is generally high at birth, is minimized through early adulthood, and then begins to increase exponentially, in line with different disease patterns. Although heart disease is rare in dogs, cancers affect both species and, in both, the risk of developing cancer increases with age. The researchers also point out that since dogs share our environment, they are likely exposed to the same environmental factors that can increase or decrease our own likelihood of a long and healthy life. Why any human or non-human animal ages at all essentially remains a mystery.

Ongoing, large-scale studies, such as the Dog Aging Project (DAP) and the Golden Retriever Lifetime Study (GRLS), are looking at ways to better understand and slow down the aging process in dogs and humans. Although laboratory research preceded these studies, these are not experiments on laboratory dogs. With information provided by interested dog owners, veterinarians, and other “citizen scientists,” researchers are following companion dogs throughout periods of their lives to determine the effect of various lifestyle (i.e., diet) and medical interventions (i.e., medication) on lifespan and age-associated decline in pet dogs. Similar companion dog research has recently shown that all dogs, regardless of their breed, size, or average lifespan, experience similar patterns of cognition from development in puppyhood through decline as they age.

Researchers who specialize in geroscience (the study of biological aging) aim to better pinpoint and define the genetic, epigenetic, and environmental factors that determine individual rates of aging. Although the research is full of unknowns, scientists predict that slowing down the aging process will ultimately be a much more effective way to improve quality of life and increase functional lifespan than treating or even curing existing individual diseases. The goal of translational geroscience research (such as the studies mentioned in the paragraph above) is to develop both a dog model for slowing down aging that might translate to human research, and also to extend the healthy lifespan of companion dogs themselves.

Evidence confirms, and dog owners know intuitively, that our bonds with dogs provide both physical and emotional benefits. Dogs not only provide companionship and affection, they also keep us physically and mentally active, make us feel safer, and help us connect with and befriend others. Their companionship may be especially important for older adults who may find their social networks and sense of purpose shrinking. Dogs give humans a reason to get out of bed each morning, and something positive to talk about, the researchers point out. Canine friends provide an important “social bridge” that might not otherwise exist among different members in a community.

Studies of adults over the age of 50 found that those who walked their dogs often were not only more likely to reach recommended exercise goals but also to report a better sense of community than those who did not walk dogs or did not have a companion dog. Dog owners reportedly walked faster and were better able to maintain their walking speed over time than non-owners, an indicator of better balance that is important for preventing falls and remaining independent. Other studies have found that the mere presence of a pet is associated with lower blood pressure levels and a lower risk of death following a heart attack.

Loneliness, social isolation, and living alone have all been shown to significantly increase the likelihood of early death. Although studies on the role of dogs and other pets in generally alleviating loneliness have shown mixed results, older adults who have regular contact with dogs have reported reduced levels of loneliness and increased mental functioning. Pets have been shown to reduce depression following the loss of a spouse and to decrease agitation and increased social functioning in people with dementia.

In spite of the many proven benefits, pet ownership declines with age. While approximately 40% of adults age 50-67 in the U.S. have a pet, this drops to only 9% of adults aged 68+. The reported reasons include the inconvenience and burden of extra work on the elderly or their family members, as well as the financial responsibility, physical and mental ability to meet the pet’s needs, restrictions set forth by an older adult’s housing circumstances, and concerns about the pet owner becoming ill or dying before the dog.

Researchers see many possibilities to meet these challenges and benefit the lives of both humans and dogs in the future and are calling for more and better quality studies as well as the funding required to prioritize related study topics. They say this type of research could help build a stronger foundation of evidence for the role of dogs in the lives of aging adults.