Research shows 40 percent of dementia cases are preventable, and Alzheimer’s Disease International’s 2023 world report gathers experts' input on the five most powerful preventive factors.
According to data compiled by the World Health Organization, the number of people living with dementia is expected to increase to 139 million in 2050 from 55 million in 2019. But science shows that 40 percent of dementia cases could be prevented. Science backs healthy lifestyle choices like diet and exercise, as well as human interaction and prolonged learning, as effective ways to delay or limit the chances of being diagnosed with dementia later in life.
Now, Alzheimer’s Disease International’s new 2023 World Alzheimer’s Report digs into the specifics, focusing on the ways to stave off a diagnosis, arguing that it’s never too early — nor too late — to focus on dementia risk reduction.
“The phrase ‘prevention is better than cure’ is not just a trite saying, but a call to action,” the report states. Positive lifestyle changes include less alcohol consumption, no smoking, healthy diet and exercise, and human interaction.
“Even the smallest of changes can make a
difference,” the report authors state,
“and we owe it to our loved ones,
our communities, but most of all
to ourselves, to try.”
According to lead author of the report, Simon Long, evidence shows that most factors intersect and “reinforce” one another. For example, the risk of high blood pressure and diabetes is exponentially higher when someone has an unhealthy diet or is immobile. Social isolation can lead to depression, and lacking hearing aids when needed can only increase social isolation.
“The basic message is one that is often trotted out as a bromide: what’s good for the heart is good for the brain,” Long wrote.
The report’s findings follow a landmark 2020 report by the Lancet commission on dementia prevention, intervention and care that outlined 12 ways to help prevent or delay a dementia diagnosis.
While not all cases of dementia are preventable, here are five things to keep in mind to aid in protecting your “cognitive reserve.”
1. Eat a healthy diet
“You are what you eat,” Long wrote. Eating a fiber-rich diet, unprocessed foods, fruits and vegetables, and avoiding too much meat and fat is beneficial.
But Long wrote that Dr. Robert Friedland, a neurologist at the University of Louisville, “stresses diet diversity” in opposition to hyper-specific diets. “It is important to eat different things,” Dr. Friedland told Alzheimer’s Disease International in the report.
Dr. Oliver Shannon, a lecturer in nutrition and aging at Newcastle University, advocates “moving away from looking at individual compounds, to whole-diet approaches.” The reason is that while people may want to adjust their eating habits, it’s more difficult to persuade life-long radical changes.
Shannon, Long wrote, “highlights the benefits that even relatively modest changes can have,” like “using more olive oil [or] swapping beer for a glass of wine.”
2. Address hearing loss
Some 65 percent of adults over the age of 60 live with hearing loss — and clinical research shows it is a controllable risk factor for dementia. But according to a Johns Hopkins study, only about 14 percent of people actually pursue the solution of getting a hearing aid — a move the Alzheimer’s Disease International report described as a “game changer” in slowing cognitive decline.
In a clinical study presented at 2023’s Alzheimer’s Association International Conference, researchers behind a study called ACHIEVE found that hearing aids were indeed a means of protecting cognitive health — particularly in people who already have higher risk factors for dementia (i.e. older age, high blood pressure, and early signs of cognitive decline.)
In December of 2022, a study followed more than 137,000 adults for a 25-year period and found that not only did people who started using hearing aids show small improvements on cognitive tests in the short term: They were almost 20 percent less likely to develop cognitive decline or dementia in the long term. In other words, hearing aids reduced the risk of dementia by one fifth.
Other studies show the risk is even greater: According to Gill Livingston, a professor in the psychiatry of older people at University College London who leads The Lancet commission, “People with hearing loss are about twice as likely to develop dementia.”
And according to Dr. Sarah A. Sydlowski, the audiology director of the Hearing Implant Program and former president of the American Academy of Audiology, checking for hearing loss is key for healthy brain aging.
“If you aren’t hearing well, you tend not to participate in those activities that stimulate your brain, through conversation or through challenging listening environments,” Sydlowski told Being Patient. “When you identify hearing loss early and start using appropriate well fitted hearing aids, you’re giving your brain access to those sounds that keep it sharp and keep it active.”
Hearing aids might “alleviate cognitive load,” the report states, meaning social interaction is enhanced, loneliness is less likely and therefore, so is the possibility of depression — all of which are risk factors for dementia.
3. Get good sleep
Sleep was not included in The Lancet’s list of risk factors, and Long wrote that studies done on sleep’s impact on cognitive health have mixed results. But research does “suggest that poor sleep patterns in middle age may contribute to a higher risk of dementia later in life.”
Sandra Giménez, a clinical neurophysiologist at the Global Brain Health Institute, says that the treatment of “obstructive sleep apnoea” — a relatively common condition in which proper breathing is disrupted while asleep — by a Continuous Positive Airway Pressure (CPAP) mask “seems to reduce the risk of Alzheimer’s.”
4. Keep learning
Long wrote that autopsies done on the brains of people who never showed any signs of cognitive decline “are riddled with the pathology of Alzheimer’s.” This is the concept of “cognitive reserve,” as explained by neurologists, and it’s possible that the “best way” to enhance this “reserve” is to “get an education early in life,” Long wrote.
But after one finishes the average and required full-time education (at around 18 years old), the building of the “reserve” does not end. “So long as the brain is exercised, it can retain and add reserve,” Long wrote.
Ways in which to “add reserve” can take on different forms: crossword puzzles, learning new languages and playing an instrument can all help.
But does the chosen brain exercise necessarily need to be challenging? Dr. Gary Small, a psychiatrist at the University of California, Los Angeles, says “There is something about challenging yourself that keeps you mentally crisp.”
5. Connect with others
Depression and social isolation are two of The Lancet’s modifiable risk factors. “Unsurprisingly, a healthy mind is more resilient to dementia than one with an illness,” Long wrote.
Studies have shown that increased social connection has benefits in staving off dementia. Depression can speed up the aging of the brain, as older adults with depression are twice as likely to develop dementia.
But social isolation is not always a lifestyle choice, but the result of ostracization.
Chloé Benoist, Alzheimer’s Disease International’s (ADI) publication’s manager, notes that dementia risk in the LGBTQI+ community is increased due to the discrimination they face, which could lead to increased social isolation, and in turn, depression. “Tackling prejudice should be an essential component of risk reduction efforts within the community and beyond,” Benoist wrote.
ADI recommends maintaining social connections: “humans are social animals; socializing replenishes our brain health and reduces depression and isolation.”
While there may not be a cure for dementia, ADI asserts that changes can be made as individuals and as a society to reduce the risk of a diagnosis.
“Even the smallest of changes can make a difference,” the report authors state, “and we owe it to our loved ones, our communities, but most of all to ourselves, to try.”