Here's a to-do list for preventing dementia, new research suggests: Ditch red meat, take a brisk walk to the grocery store, do the Sunday crossword and stick to one glass of wine at dinner.
A study presented Sunday at the Alzheimer's Association International Conference in Los Angeles found that combining five lifestyle habits - including eating healthier, exercising regularly and refraining from smoking - can reduce the risk of Alzheimer's by 60 per cent. A separate study showed that lifestyle choices can lower risk even for those who are genetically prelifestyle disposed to the disease.
The report, compiled by the Rush University Medical Center in Chicago, tracked 2765 individuals over about a decade. All participants were older adults enrolled in either the Chicago Health and Aging Project (CHAP) or the Rush Memory and Aging Project (MAP), both federally funded, long-term observational studies that examine mental decline among aging Chicago residents.
Over the last decade, studies have increasingly pointed to controllable lifestyle factors as critical components for reducing the risk of cognitive decline. Researchers say that, as with heart disease, combating dementia will probably require a "cocktail" approach combining drugs and lifestyle changes. And as recent efforts to develop a cure or more effective drug treatments for dementia have proven disappointing, the fact that people can exert some control in preventing the disease through their own choices is encouraging news, they say.
While the new study's authors expected to see that leading a healthier life decreases the chance of dementia, they were floored by the "magnitude of the effect," said Klodian Dhana, a Rush University professor and co-author.
"This demonstrates the potential of lifestyle behaviours to reduce risk as we age," said Heather Snyder, senior director of medical and scientific operations at the Alzheimer's Association. "The fact that four or five lifestyle habits put together can have that kind of benefit for your brain is incredibly powerful."
The Rush team assessed study participants' lifestyles on five metrics: their diet, their exercise regimen, whether or not they smoked, their alcohol consumption and their "engagement in cognitive stimulation activities," Dhana said. The researchers then scored each factor, assigning participants a "1" if their behaviour was healthy in that category and a "0" if it was unhealthy.
Individuals who ate a "high-quality diet" of mostly vegetables, nuts, berries, beans, whole grains, seafood, poultry and olive oil - while avoiding red meats, butter, cheese, pastries, sweets and fried food - earned 1s. This was also true for anyone who exercised at least 150 minutes a week, whether by biking, walking, swimming, gardening or doing yard work.
People who did not smoke, limited themselves to one glass of wine a day, and regularly - two or three times a week - engaged in mentally stimulating activities like reading the newspaper, visiting the library or playing games such as chess and checkers also earned 1s.
After crunching the numbers, Dhana and his colleagues found that individuals with a score of 4 or 5 - meaning they pursued four or five healthy behaviors over the period studied - were 60 per cent less likely to develop Alzheimer's compared to participants who scored 0 or 1. The results did not vary by race or gender, Dhana said.
The average age of participants in the CHAP cohort was 73 and in the MAP cohort, 81. The population studied included both men and women and blacks and non-Hispanic whites.
Around 50 million people have dementia worldwide, and that number is expected to triple by 2050, according to the 2018 World Alzheimer Report. The global cost of dementia in 2018 was roughly $1 trillion, a figure projected to double by 2030.
If you cannot adopt all four or five healthy lifestyle habits studied, aim for one or two - whatever you can do, Dhana said. Anything will help: The Rush team found that making just one more healthy choice, no matter how many participants had already made, decreased their chance of Alzheimer's by an additional 27 per cent.
And, if you're trying to decide which habits to adopt, Dhana has his favorites.
"My biggest takeaway is I encourage older people to consume more leafy green vegetables, replace red meat with poultry, and avoid as much as possible fried food," he said. "Also, walk to the grocery store and read books!"
Another study also presented Sunday found that lifestyle choices may even counteract genetic predisposition for Alzheimer's. That research, led by a team at the University of Exeter Medical School, showed that people with a high genetic risk of Alzheimer's were less likely to develop the disease if they pursued a healthy lifestyle.
Synder said she expects to see more studies examining the role of lifestyle choices going forward.
"I think we will see people honing in on, 'What are the specific aspects of these behaviours that are already identified?'," she said. "But I also think we'll see people asking, 'What are other behaviours?'"
Snyder said she would not be surprised if the number of recommended lifestyle choices eventually rose as high as 10 or 12.