While dementia is not necessarily preventable, scientists now understand even more clearly the extent to which some lifestyle changes can significantly lower one’s odds of developing dementia. Here are 12 risk factors that could potentially delay or prevent 40 percent of dementia cases worldwide.
Researchers project the number of people living with dementia, a neurodegenerative syndrome which currently afflicts 50 million people worldwide, will more than triple by 2050, soaring to 152 million cases globally. But experts in a recent report say two in five dementia cases could potentially be delayed or prevented by certain lifestyle choices and government policies.
The report builds on the previous nine risk factors identified by the Lancet Commission on dementia prevention, intervention and care, and adds three additional risk factors — air pollution, traumatic brain injury and excessive consumption of alcohol.
Eric Larson, an author of the study and senior investigator at Kaiser Permanente Washington Health Research Institute in Seattle, said just as people can’t control their genetics, people in their 40s can’t retroactively change their socioeconomic circumstances in early life — but people of all ages can, to varying extents, make lifestyle choices like habitual exercising to improve their health.
“In my own [clinical] practice, I’ve been telling patients it would be a good idea to exercise regularly,” Larson said. “When they found out that you could preserve your brain and reduce your risk of dementia, it was actually a powerful motivator for many people to become a regular exerciser.”
Various risk factors from early life to midlife and old age are linked to people’s risk of dementia. Less education before the age of 45 is associated with seven percent of dementia cases. The leading risk factor from the age of 45 to 65 is hearing loss, which is linked to eight percent of dementia cases followed by traumatic brain injury, hypertension, alcohol and obesity. Smoking at ages older than 65 is linked to five percent of dementia cases, followed by depression, social isolation, physical inactivity, air pollution and diabetes.
“There is a lot you can do to reduce your risks. It will not all be relevant to you, see what applies to you and how you can change it,” Gill Livingston, an author of the report and a professor of psychiatry of older people at University College London, wrote in an email.
The Lancet team further urged policymakers to take active steps to create and prioritize policy that may help prevent dementia. They issued recommendations to prioritize childhood education for all, implement public health initiatives to minimize head injuries and hasten efforts to improve air quality, among other recommendations.
Being Patient takes a closer look at how each risk factor is linked to dementia.
1. Education and Cognitive Health
Receiving more education in early life may reduce risk of dementia. According to Lon Schneider, an author of the report and professor of psychiatry, neurology, and gerontology at the University of Southern California, the more we learn, the more “cognitive reserve” we build up. While connections between brain cells, also known as synapses, may falter due to aging and sickness, “You have more reserves to start with, so you’re more resilient” against illnesses, said Schneider.
Here’s what you can do: Engaging in intellectual activities later in life can potentially help maintain cognitive abilities. One study in China which found people older than the age of 65 who read, played games or bet more frequently were less likely to develop dementia. Another study showed that people who participated in intellectual, physical and social activities in midlife were more likely to have better cognition in old age.
Read more about past research on the link between early childhood education and Alzheimer’s disease, the most common form of dementia.
2. Hearing Loss and Dementia Risk
People with hearing loss in midlife are at a higher risk of dementia. Older adults with hearing problems also have higher odds of dementia — except for those who use hearing aids. “[Hearing loss is] socially isolating,” Larson said. “Social isolation and inability to engage with others in speech and listening has a detrimental effect on maintaining brain reserve.”
Here’s what you can do: To prevent hearing loss, Larson urged people to avoid excessive noise. Those who have hearing difficulties should seek testing and, if appropriate, use a hearing aid.
Read more about past research on the link between hearing loss and cognitive decline
3. The Link Between Traumatic Brain Injury and Dementia Risk
Traumatic brain injury (TBI), a risk factor in midlife, is often caused by injuries sustained from automobile, sports accidents and exposure to blasts among members of the military. Severe TBI is linked to abnormal tau proteins, a biomarker of Alzheimer’s. People aged 50 years or older with a history of TBI are at an increased risk of dementia compared to those without TBI.
Here’s what you can do: To reduce risk of falls for older adults, doing balance exercises and maintaining muscle strength especially in the legs is crucial, Larson said. Lookout for items around your home which can cause a trip. And avoid walking on slick surface barefoot or with stockings.
Read more about past research on TBI and dementia among military veterans, and the different proteins involved in TBI.
4. High Blood Pressure and Dementia Risk
High blood pressure can cause blood clots in arteries, blocking blood flow to the brain. Stroke and the loss of brain cells may follow, and the brain could subsequently shrink.
People with high blood pressure in midlife are more likely to develop dementia later in life (some researchers suggest high blood pressure, as early as our 30s, could increase risk of dementia later on).
Here’s what you can do: “Make sure you know your blood pressure if you are 40,” Livingston said. The Lancet team recommended aiming for a systolic blood pressure — the pressure of the blood against artery walls as the heart beats — of 130mm Hg or less in midlife, though Larson cautioned against reaching an overly low blood pressure.
Experts say managing stress and sleeping well, maintaining a stable weight and eating a healthy diet of less sugary foods, exercising regularly and refraining from smoking can help control blood pressure.
Read more about past research on the link between hypertension and dementia, and insights on how hypertensive treatment may reduce risk of cognitive decline
5. Dementia and Excessive Drinking
According to Andrew Sommerlad, an author of the report and a senior research fellow at University College London, excessive consumption of alcohol can lead to damaged brain cells and blood vessels, shrinkage of brain tissues and severe nutritional deficiencies. And one study shows alcohol use disorder is a major risk factor for all types of dementia, especially early-onset dementia which strikes people before the age of 65.
Here’s what you can do: The Lancet team suggested drinking less than 210 milliliters of alcohol weekly, the amount of alcohol which appears to reduce risk of dementia. For people who are chronic drinkers, Sommerlad said cutting back on alcohol a little each day by having smaller or lower-strength drinks is likely the safest and most effective way to reduce the consumption of alcohol.
“Recognizing the problem and setting a realistic target for reducing your alcohol intake is a really important first step,” he said in an email. “Reducing alcohol intake is often difficult for people who have been chronic heavy drinkers, and it is a good idea to consult with a healthcare professional about how to approach this as well as seeking help from organizations and friends or family to support this process.”
Read more about past research on how alcohol use can affect different regions of the brain
6. Obesity and Dementia Risk
Research shows people who are obese are more likely to develop dementia later in life. Some researchers say obesity should be considered premature aging, as it is strongly linked to chronic health problems in old age.
According to Adesola Ogunniyi, an author of the report and a professor of medicine at University of Ibadan, Nigeria, obesity is a risk factor for chronic cardiovascular diseases, which damage blood vessels in the brain and reduce blood flow. This leads to a cascade of inflammation and oxidative stress — an imbalance between oxygen-containing molecules and antioxidants — which would eventually lead to the death of brain cells.
Here’s what you can do: Ogunniyi recommended losing weight, avoiding excess calories and reducing sugary beverages along with staying active and exercising.
Read more about past research on the link between obesity in midlife, body mass index (BMI) and dementia
7. Smoking and Dementia Risk
“Smoking is likely to increase risk of dementia as it causes problems with blood vessel function meaning that a person is more likely to have small strokes or small bleeds in the brain, and it may also be that chemicals in tobacco smoke [can] cause inflammation,” Sommerlad said.
Here’s what you can do: Even if you’re a smoker, it’s not too late to stop smoking. After all, older adults who stop smoking may substantially reduce their risk of dementia. Get help to stop smoking, Livingston said, such as by using nicotine patches.
Read more about past research on the link between smoking and dementia
8. Depression and Dementia Risk
People who are developing dementia are more likely to become depressed, Livingston said. Depression is also a risk factor of dementia, though she noted that researchers still aren’t sure why. Some scientists suggest depression can speed up brain aging and lead to shrinking of the brain.
Here’s what you can do: Exercising and interacting with at least some people can help with depression and lower our risk of dementia, Livingston said. As the causes of depression vary among individuals, she recommended people with depression to see their general practitioner, and decide whether therapy or medication would help.
Read more about past research on cognitive decline and depression
9. How Social Isolation Can Lead to Dementia
Forming social connections can enhance a person’s cognitive reserve. In other words, paying attention to others and interacting with them keeps our brains active and healthy, Livingston said.
Additionally, some studies find the opposite — social isolation — may increase people’s risk of dementia. One study shows that people who are single lifelong and those who are widowed are more likely to have dementia compared to married couples.
Here’s what you can do: Livingston suggested seeing and talking to people, walking with others and chatting over tea, coffee or food — activities you may find pleasure in doing with others. She reminded us of an important point amid the coronavirus shutdown, a public health crisis which has left many feeling socially isolated: “Try to be physically distant but not socially distant.”
Read more about past research on the link between social connection and dementia
10. Exercise for Cognitive Health
According to a number of studies, staying physically active and exercising regularly appears to reduce the risk of developing dementia. Researchers suggest exercise may trigger neurochemicals and the birth of neurons in the brain, improving mood, memory and learning. It’s never too late to start exercising, experts say: People who improve their fitness over time are less likely to develop dementia.
Here’s what you can do: Aspire to exercising 150 to 210 minutes of exercise a week, Larson said. It can be a lot for some people, he admitted. And 15 minutes of exercise three times a week can go a long way compared to staying inactive.
“People tend not to realize that you don’t have to be a marathon runner,” Larson said. “You just have to have regular physical activity. The greatest danger is not doing anything.”
Read more about past research on the enduring benefits of exercise, and how it affects mood and cognition
11. The Link Between Air Pollution and Dementia
Air pollution isn’t just harmful for our respiratory health: Emerging evidence shows that people who are exposed to air pollution are at a higher risk of dementia. In fact, people who live close to major roads and freeways, have higher odds of developing dementia. And some scientists have suggested that exposure to air pollution can lead to brain inflammation.
Here’s what you can do: Avoid the outdoors when air pollution levels are high, Larson said, such as instances of wildfires. Meanwhile, researchers urge policy makers to consider increasing people’s access to green spaces, reducing traffic and the number of highways in residential areas.
Read more about past research on the link between heart disease, Alzheimer’s, and air pollution
12. How Diabetes Drives Dementia Risk
Diabetes is linked to the degeneration of small blood vessels as well as strokes — which are in turn risk factors of dementia. It is possible beta-amyloid plaques and tau tangles, the biomarkers of Alzheimer’s, play a role in high blood sugar levels, Larson said. But more research is needed to pinpoint biological mechanisms linking diabetes and dementia beyond those related to blood flow.
Most people have type 2 diabetes, which leads to a two-fold increased risk of developing Alzheimer’s. As cells fail to respond to insulin — the hormone that manages blood sugar levels — the body produces more insulin, which in turn, leads to overly high levels of blood sugar.
Here’s what you can do: Researchers warn that type 2 diabetes and Alzheimer’s are “reaching epidemic proportions,” as they urge people to manage their stress, get a good night’s sleep, maintain a balanced weight, eat a healthy diet with less sugary beverages, stay active and exercise regularly.
Read more about past research on the link between the brain’s metabolic function, diabetes and dementia