Living with a dog halves dementia risk in Tokyo seniors, study finds

Could a dog be good for your brain? A large Japanese study suggests that older people who live with a dog develop dementia only half as often as those who don't.

What did the researchers find?

Scientists at Japan's National Institute for Environmental Studies followed 11,200 residents of a Tokyo district for more than seven years. Most were seniors aged 65 to 84. There were roughly as many men as women, from a range of social backgrounds.

At the start, everyone was asked whether they had a pet: a dog, a cat or something else. Then, with doctors, the team regularly tracked their cognitive health, including the onset of dementia and Alzheimer's-type diseases.

The result: the risk of dementia was twice as low among people living with a dog. For cat owners, there was no difference.

Why would a dog make a difference?

The researchers point to several effects that add up. A dog needs to go out once or twice a day, so its owner gets some walking and physical activity.

There are also more social contacts, with chats on the street or in the park. And even at home, a dog constantly calls on your cognitive functions. In short, it keeps your brain busy.

The study reports a link between owning a dog and lower dementia risk. The researchers' explanations are the factors they believe are behind it.

What does it mean for health budgets?

Fewer people with Alzheimer's means fewer medical treatments, more people able to stay at home and fewer needing a place in a hospital or specialised care home.

The team tried to estimate the potential savings for the state. If the share of seniors who own a dog rose to 13%, they say, care costs would fall by more than 150 billion yen (about 850 million euros) a year.

That is why the story ends on a half-joke: to save money, a government could start handing out puppies. A dog is a long commitment, though, and the study doesn't say it is the right choice for everyone.