Why Do Dogs Get Dementia? Study Finds Similar Risk Factors to Humans

Dogs seem to have a lot in common with people when it comes to dementia, new research suggests. The study found that dogs face an increasingly higher risk of dementia for every year past the age of 10, and the likelihood of dementia appears to be lower for dogs that are more physically active and higher for those with a history of eye or ear problems.

The findings are the latest to emerge from the Dog Aging Project, an initiative that’s billed as the most ambitious dog health study in the world. The basic premise involves tracking tens of thousands of pet dogs over a 10-year period in order to hopefully find the factors that can lead to a long and healthy lifespan.

In this new research, published Thursday in Scientific Reports, the authors analyzed survey data collected from late 2019 to 2020 from the owners of over 15,000 dogs. The owners were asked questions about their pooch’s general health and lifestyle, as well as their cognition. One survey asked people if their dogs exhibited possible symptoms of canine cognitive dysfunction, or dog dementia, such as whether the dogs had trouble remembering familiar faces or had trouble sleeping.

The dogs’ ages were divided in quarters, based on their expected lifespan, with 19.5% being in their last stretch of life. Ultimately, 1.4% of dogs were considered to have dementia. Based on age alone, the odds of diagnosed dementia rose by 68% for each added year in dogs past 10. And even when taking other important factors into account, such as health problems and breed, the odds of dementia still rose by 52% each year for dogs after age 10.

The results line up with other research showing that older dogs have the most to worry about when it comes to dementia. And though there are some kinds of dementia that can affect the young or strike at any age, longevity remains the biggest risk factor for dementia in humans as well.

That said, many studies have indicated that there are some aspects of our lives and health that can be changed or prevented to reduce the risk of dementia, and the same appears to be true for our best friends. Among dogs of the same breed, age, and general health, for instance, the odds of CCD were more than six times lower for dogs that were said to be regularly physically active, compared to those that weren’t active. And just as some research has shown in humans, dogs with a history of neurological, ear, or eye conditions also had a higher risk of dementia.

The scientists caution that these findings are observational and are right now based on a single moment in time, meaning that they can’t show a clear causal relationship between these linked factors. It’s possible, for example, that the results can be explained by dogs with early dementia starting to move around less, rather than sedentary dogs being more prone to dementia as they age.

“Additional studies that further explore factors that will provide a better understanding of canine cognitive function are needed,” they wrote.

Studies in humans continue to show the importance of exercise in maintaining a healthy body and brain as we age, so it really wouldn’t be a surprise if the same applied to dogs, too. As the project goes on, scientists will be able to start collecting the sort of long-term data that can better establish a clear cause-and-effect link between dementia and these risk factors.

The current study’s findings, its authors say, suggest that screening for dog dementia can be improved. Veterinarians could take into account a dog’s expected lifespan based on their weight and breed, for instance, when deciding whether to test them for dementia. And given the parallels we’re seeing between dog and human brain health, they add, dogs could perhaps one day serve as an important model animal to better understand aging and dementia in humans, which sadly remains untreatable in both species.

Dogs seem to have a lot in common with people when it comes to dementia, new research suggests. The study found that dogs face an increasingly higher risk of dementia for every year past the age of 10, and the likelihood of dementia appears to be lower for dogs that are more physically active and higher for those with a history of eye or ear problems.

The findings are the latest to emerge from the Dog Aging Project, an initiative that’s billed as the most ambitious dog health study in the world. The basic premise involves tracking tens of thousands of pet dogs over a 10-year period in order to hopefully find the factors that can lead to a long and healthy lifespan.

In this new research, published Thursday in Scientific Reports, the authors analyzed survey data collected from late 2019 to 2020 from the owners of over 15,000 dogs. The owners were asked questions about their pooch’s general health and lifestyle, as well as their cognition. One survey asked people if their dogs exhibited possible symptoms of canine cognitive dysfunction, or dog dementia, such as whether the dogs had trouble remembering familiar faces or had trouble sleeping.

The dogs’ ages were divided in quarters, based on their expected lifespan, with 19.5% being in their last stretch of life. Ultimately, 1.4% of dogs were considered to have dementia. Based on age alone, the odds of diagnosed dementia rose by 68% for each added year in dogs past 10. And even when taking other important factors into account, such as health problems and breed, the odds of dementia still rose by 52% each year for dogs after age 10.

The results line up with other research showing that older dogs have the most to worry about when it comes to dementia. And though there are some kinds of dementia that can affect the young or strike at any age, longevity remains the biggest risk factor for dementia in humans as well.

That said, many studies have indicated that there are some aspects of our lives and health that can be changed or prevented to reduce the risk of dementia, and the same appears to be true for our best friends. Among dogs of the same breed, age, and general health, for instance, the odds of CCD were more than six times lower for dogs that were said to be regularly physically active, compared to those that weren’t active. And just as some research has shown in humans, dogs with a history of neurological, ear, or eye conditions also had a higher risk of dementia.

The scientists caution that these findings are observational and are right now based on a single moment in time, meaning that they can’t show a clear causal relationship between these linked factors. It’s possible, for example, that the results can be explained by dogs with early dementia starting to move around less, rather than sedentary dogs being more prone to dementia as they age.

“Additional studies that further explore factors that will provide a better understanding of canine cognitive function are needed,” they wrote.

Studies in humans continue to show the importance of exercise in maintaining a healthy body and brain as we age, so it really wouldn’t be a surprise if the same applied to dogs, too. As the project goes on, scientists will be able to start collecting the sort of long-term data that can better establish a clear cause-and-effect link between dementia and these risk factors.

The current study’s findings, its authors say, suggest that screening for dog dementia can be improved. Veterinarians could take into account a dog’s expected lifespan based on their weight and breed, for instance, when deciding whether to test them for dementia. And given the parallels we’re seeing between dog and human brain health, they add, dogs could perhaps one day serve as an important model animal to better understand aging and dementia in humans, which sadly remains untreatable in both species.