What is the risk of your dog developing dementia?

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When Dante turned 8, he started to look a little bad. The 31-kilogram Bernese Cattle Dog roamed his family’s home in Interlaken, New York, like a caged bear. At other times he would remain motionless, staring at the pedals of the family organ, as if in a trance. Or staring into a corner of the room. He would wake up in the middle of the night and start barking nonstop for no obvious reason.

And then the incontinence began inside the house.

A brain scan confirmed that Dante had canine cognitive dysfunction, known colloquially as canine dementia and often described as the analogue of Alzheimer’s disease in dogs. Some studies find that at least 14% to 35% of older dogs can develop the problem. But, because the symptoms resemble those of other diseases, it is difficult to confirm the real prevalence of this disease.

A large study of 15,019 dogs enrolled in the Canine Aging Project, an ongoing investigation into disease and aging in dogs, was published Thursday in Scientific Reports, and identifies the main factors associated with a dog’s risk. develop the disease.

One of the key findings of the study is that physical exercise can play an important preventive role. The odds of a diagnosis of cognitive dysfunction were 6.47 times higher in non-active dogs compared to very active ones, researchers at the University of Washington said. But they noted that the disease itself can lead to lack of exercise, noting that the study results, which are based on observations made by dog ​​owners, suggest correlation rather than cause and effect.

The chances of contracting the disease also appear to increase in dogs that have neurological disorders or impaired hearing or vision. Annette Fitzpatrick, a co-author of the study and a research professor at the University of Washington with experience in human as well as canine dementia, commented, “When you’re not getting input from the outside world, it seems to increase your risk of not being able to use your own brain as well.” .

According to her, the study reveals “that there may be other things that we can become aware of in order to try to reduce the onset of cognitive dysfunction.”

And age matters, no doubt. A dog’s life expectancy often depends on its breed, size and body mass: think of a mastiff (6 to 12 years old) versus a chihuahua (12 to 20 years old). The study found that in the last years of the dog’s projected life, each successive year contributes to the potential for onset of dementia.

In fact, the researchers noted, the risk factors correlated with canine cognitive dysfunction mirror some of the risk factors of humans with dementia, including Alzheimer’s disease.

Previous studies of canine cognitive dysfunction were often based on assessments by veterinarians of smaller populations of older animals; this study involved dogs whose ages ranged from infancy to their mid-20s.

In the coming years, as these dogs age, the project — which already has more than 40,000 dogs enrolled and hopes to reach 100,000 — will release more complex conclusions about cognitive dysfunction and other canine diseases.

In this study, the prevalence of canine cognitive dysfunction among all dogs, young and old, was 1.4%. But the median age of the dogs studied was just 6.9 years, and only 19.5% of the dogs studied were in the last quarter of their lifespan.

“This study compares dogs with cognitive dysfunction with dogs that don’t have the disease,” Fitzpatrick said. “But over the years we will be able to look at the same dog that maybe had great cognitive function, but then it deteriorated.”

The results were derived from just one report by dog ​​owners of their dog’s health and lifestyle between 2019 and 2020, plus a particularly high-threshold cognitive function questionnaire.

Among the questions asked were:

  • How often does your dog pace, walk in circles, or wander aimlessly or aimlessly?
  • How often does your dog get stuck behind objects and can’t get around them?
  • How often does your dog bump into walls or doors?
  • How often does your dog have trouble finding food lying on the floor?

If the study’s findings sound familiar, even intuitive, it may be because the Canine Aging Project, which receives funding from the National Institute on Aging, a branch of the National Institutes of Health, may shed light on factors that affect lifespan. of humans, in addition to the dogs that live with them.

Unlike laboratory animals like mice and fruit flies, dogs that live with humans are affected by their owners’ environmental and social factors, such as secondary cigarette smoke, pesticides used on lawns, and access to health care.

“Human longevity estimates say that about 75% of it is due to the environment and 25% is genetic,” said Matt Kaeberlein, a biogerontologist who is co-director of the Canine Aging Project. “So dogs that live with humans offer us the opportunity to really understand the role of this environmental variability in the biological aging process.”

In addition, because dogs age much faster than humans, the ongoing studies in the project offer opportunities for an accelerated timeline of insights into human and canine aging.

Kaeberlein’s motivation stems not only from her professional training, but from the fact that she has had dogs for many years. He shared stories about Chloe, his now-defunct keeshond dog, who was cheerful and affectionate, but began staring into space and crashing into furniture, stricken with canine cognitive dysfunction. Or Dobby, his current inspiration, a long-haired German Shepherd who is “just a very special dog” but who, at the age of 12, has overcome cancer and can no longer jump and play in the backyard, chasing after soap bubbles.

“I really wish my dogs could live longer,” Kaeberlein said. “And I would love to be able to help other people’s dogs live longer.”

Trials currently underway on the project, which began in 2014 and has researchers from Washington University and Texas A&M, as well as Cornell University College of Veterinary Medicine and other universities, include studies of potentially life-extending drugs and a tissue biobank donated by dog ​​owners who died. The project launched a study that is causing repercussions in the canine world with its conclusion that the best health of dogs is correlated with a single daily meal.

(In the phone interview, while Kaeberlein was talking about this correlation, two small, highly food-motivated dogs that were dozing beside the reporter suddenly woke up, groaning and howling in protest. Kaeberlian was quick to add that the observation is more likely to be linked to obesity and morbidity, and less likely to reflect a recommendation on eating frequency. This is consistent with the positive correlation with exercise made in the most recent study.)

Canine cognitive dysfunction is difficult to pinpoint accurately. When a dog seems to ignore a common command, it could be a sign of age-related deafness or stubbornness rather than brain atrophy. Symptoms that look like cognitive dysfunction could actually be stroke, brain inflammation, diabetes or Cushing’s disease, said veterinarian Nicole Ehrhart, director of Colorado State University’s Columbine Health Systems Center for Healthy Aging.

According to her, veterinarians are initially guided by the observation of the owners and only after that they carry out diagnostic tests.

“Look your dog in the eye and see how long he can hold your gaze, especially if you’re holding a treat next to his face,” she said. “When dogs get dementia, they can’t focus their eyes on the things they normally would.”

Ehrhart, who was not involved in the Canine Aging Project study, described the new research as “an excellent confirmation of something we already know that applies to all species: that exercise is good for healthy aging and that Lifetime exercise may have a preventive effect on Alzheimer’s disease and other cognitive problems.”

In fact, the average life expectancy of Bernese herders is between 6 and 8 years; Dante is now 11. But he was especially active in his youth: he had the physical and mental acuity to easily pass competitions involving complex obstacles and jump from the top of a ladder without getting hurt.

Now, though, this dog, who is usually so affectionate, avoids his household: three golden retrievers and two humans who adore and care about him. Instead, he prefers to lie under his favorite bush, even in torrential rain.

“I used to make an effort to convince him to come in and stay with us,” said his owner, Lisa Mitchell. “But after a year I thought, ‘Tomorrow maybe his last day of life, and maybe he’ll be more comfortable there.’ So we’re just letting him be alone in the backyard, since that’s where he wants to be.”

While there are medications and diets that can improve a dog’s cognitive dysfunction for some time, Ehrhart said, owners need to be aware of their pet’s increasing disorientation. Don’t disturb his routines. Do not move furniture around. Keep your yard well fenced so the dog can’t get out and get lost. If you want to have a noisy party with humans your dog doesn’t know, put the dog in a comforting, less stimulating environment.

And be aware that dogs, like elderly humans, can exhibit “sunset syndrome”: increasing anxiety and disorientation as the day draws to a close.

“We found that the best model of human aging has been aging alongside us for hundreds of years,” said Ehrhart. “It’s a two-way street: anything we do to improve the health and lifespan of our dogs is likely to improve ours, and anything we do for humans is very likely to benefit dogs. And who doesn’t want that? ?”

Translation by Clara Allain

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