The key to a long life of mental acuity depends, in part, on how secure a person feels about getting older in the first place.
New research published today (Feb. 7) in the Public Library of Science supports the idea that cultural constructs around how people perceive age contribute to the development of dementia. People who associate old age with uselessness or senility are more likely to develop dementia than people who associate it with positive attributes, such as wisdom and respect.
The research also highlights how environmental factors are important to consider when looking for ways to prevent dementia. Other factors that increase risk include stroke and smoking. The study was carried out by a team of Yale University scientists, led by epidemiologist Becca Levy. During time spent in Japan, Levy says, she began thinking about digging more into the causes of dementia.
“Japanese elders were treated by society more positively than I was used to seeing in the US,” Levy tells Quartz. “Japanese adults have some of the longest life spans in the world.”
The country ranks second in the world for life expectancy after Monaco, according to data from the US Central Intelligence Agency. Meanwhile, the US—among the wealthiest countries on the planet—is ranked 43rd, with an average life expectancy of 80 years.
|Top 15 countries||Average life expectancy|
As part of the study, researchers worked with a group of 4,765 people with an average age of 72. By taking saliva samples, they were able to determine which of the participants carried a specific gene linked to higher risk of dementia. All humans are born with what are called APOE genes. There are three types: APOE-2, APOE-3, and APOE-4. The latter is associated with higher dementia risk. The researchers were able to determine that 1,250 participants carried it. That group represented the core of the study.
Over the course of four years, Levy and her team contacted participants by phone and with written questionnaires to gauge their thoughts on aging. They were asked to rank the way they felt on a numeric scale. One of the prompts, for example, was: “The older I get the more useful I feel.”
The researchers found that the people with a more positive attitude toward aging had a 2.7% risk of developing dementia. Those with a more negative outlook had a 6.1% risk. The statistical difference between might seem small, but Levy suspects more research would show a starker contrast. “It’s over a four-year period, so it wasn’t very long,” she says. “If they were followed for decades the numbers would have been much higher.”
The work raises interesting questions about different cultures, and how people over the course of their lives develop perceptions about age. It essentially lays a foundation for creating a public health campaign to beat back against ageism and negative beliefs about aging, Levy has said.