Editor's note: This popular story from the Daily Briefing's archives was republished on June 29, 2020.
Five lifestyle factors could have a significant effect on the risk of developing Alzheimer's disease, according to a study presented at the Alzheimer's Association International Conference, while another study, published in JAMA, found lifestyle changes could lower dementia risk even for those genetically predisposed to the disease.
For the first study, researchers from Rush University Medical Center tracked 2,765 older adults enrolled in either the Chicago Health and Aging Project or the Rush Memory and Aging Project over about a decade, the Washington Post reports.
The researchers assessed each participants' Alzheimer's disease risk as it relates to five lifestyle factors:
The researchers then assigned a score of "1" or "0" for each factor. A score of 1 represented a healthy behavior, such as a diet avoiding red meats and fried foods, having just one glass of wine a day, or engaging in mentally stimulating activities two to three times a week. A score of 0 represented an unhealthy behavior.
Participants with a total score of 4 or 5 were found to be 60% less likely to develop Alzheimer's compared with participants who scored a 0 or 1. According to Klodian Dhana, a professor at Rush University and co-author of the study, these results did not vary by race or gender.
Dhana said he and his co-authors expected that leading a healthier life would decrease dementia risk, but were shocked by the "magnitude of the effect."
Dhana added that if you can't adopt all five of the health lifestyle habits the researchers studied, try to at least adopt one or two. "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," Dhana said. "Also, walk to the grocery store and read books!"
Ronald Petersen, director of the Mayo Clinic Alzheimer's Disease Research Center who was not involved in the study, said the Rush study "reinforces the notion that some of these lifestyle factors may actually affect the trajectory of cognitive aging and the development of dementia. We certainly accept that with heart disease. We need to adopt a similar mindset for cognitive aging."
For the study published in JAMA, a research team led by those from the University of Exeter Medical School in England looked at whether lifestyle factors can lower genetic predisposition to Alzheimer's disease and other forms of dementia.
The researchers studied almost 200,000 people ages 60 or older using the UK Biobank. These individuals, all of whom were of European ancestry, had no symptoms or signs of dementia at the start of the study. Participants self-reported their lifestyle.
After about eight years, the researchers found that 1.78% of participants with a high genetic risk of developing dementia and poor lifestyle habits had developed dementia, compared with 1.13% of participants with a high genetic risk and healthy lifestyle habits. Among participants with a low genetic risk of developing dementia and healthy habits, 0.56% developed dementia.
Rudy Tanzi, a genetics expert at Massachusetts General Hospital who was not affiliated with the study, explained that less than 5% of gene mutations tied to Alzheimer's are "fully penetrant," meaning they guarantee someone will get the disease. "That means that with 95% of the mutations, your lifestyle will make a difference," Tanzi said. "Don't be too worried about your genetics. Spend more time being mindful of living a healthy life."
However, Tara Spires-Jones, leader of the UK Dementia Research Institute program, cautioned, "While this well-conducted study adds to data suggesting that a healthy lifestyle can help prevent dementia in many people, it is important to remember that some people will develop dementia no matter how healthy their lifestyle."
She added, "We need more research into the brain changes that cause the diseases underlying dementia symptoms in order to develop effective preventions and treatments for everyone affected by dementia" (Natanson, Washington Post, 7/14; Carroll, NBC News, 7/14; Marchione, AP/New York Times, 7/14; Christensen, CNN, 7/14; Kelland, Reuters, 7/14; Lourida et al., JAMA, 7/14).
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