Owning a dog reduces the risk of dementia by 48%, surveyed over 10,000 people living in Tokyo

The paper ``Investigating the Potential Protective Effect of Dog Ownership on Incident Disabling Dementia and Its Cost-Effectiveness,'' published in the international academic journal ``International Journal of Environmental Research and Public Health'' by researchers affiliated with the National Institute for Environmental Studies and the University of Tokyo, is a research report that investigated the effect of owning a dog on the risk of developing dementia in the elderly and its cost-effectiveness.

The study surveyed 11,224 elderly people aged 65 to 84 living in Tokyo over a period of seven and a half years. The participants included 963 (8.6%) current dog owners, 2,539 (22.6%) past dog owners, and 7,722 (68.8%) non-breeders who had never owned a dog before. During the follow-up period, 1989 people (17.7%) developed dementia requiring care.

An analysis of dog ownership and the risk of developing dementia (instrumental variable analysis) showed that current dog owners had a 48% lower risk of developing dementia requiring care compared to non-breeders. However, there was almost no clear difference in the onset of dementia among previous owners.

Research suggests there are three main reasons why owning a dog has such a positive impact on your mental and physical health. The first is the possibility of relieving the lack of exercise by walking the dog every day, and preventing isolation by talking with neighbors while walking.

The second possibility is that oxytocin (the love hormone) secreted when you look at or touch a dog has a positive effect on brain function and metabolism. Third, walking dogs increases the chance of coming into contact with nature and soil bacteria, which may enrich the dog's intestinal environment and strengthen its immune system.

The research team also looked at the economic effects of dog ownership. According to the research team's calculations, if the number of dog owners increases to 13.4% of elderly people in Japan, the additional cost to society as a whole, including household expenditures such as food costs, would amount to approximately 4.63 trillion yen over four years.

There were also findings from a public payment perspective. It was also found that by owning a dog, elderly people can maintain their health and reduce medical and nursing care costs by approximately 592 billion yen over four years.