Can Dementia Be Prevented? What the Research Says

If you are caring for someone with dementia, or you have watched a parent live with it, you have probably wondered whether it could have been stopped, and whether you can stop it happening to you. This page sets out what the research actually says, in plain language. The short answer: no one can promise to prevent dementia, but research suggests that some risks can be lowered, and that lowering them across a population may mean fewer people develop dementia or develop it later.

This is general information, not medical advice. Please read our medical disclaimer and talk with a doctor about your own health.

Can dementia be prevented?

There is no proven way to prevent dementia for any single person. The National Institute on Aging (NIA) says that while nothing has been proven yet to prevent Alzheimer’s, researchers have found promising strategies and are learning what may and may not work.

What research does show is that certain health conditions and habits are linked with a higher chance of dementia. When those risks are lower across a whole population, fewer people may develop dementia, or they may develop it later in life. That is very different from a guarantee.

One hopeful sign: the 2024 Lancet Commission reported that in some high-income countries, including the US and UK, the share of older people with dementia has fallen. The authors think this is probably due in part to better education, better health care and less damage to blood vessels over a lifetime, according to University College London’s summary of the report.

What did the 2024 Lancet Commission find?

The Lancet Commission on dementia prevention, intervention and care is a group of 27 dementia researchers who review the evidence every few years. Their 2024 report named 14 risk factors that can potentially be changed, and estimated that together they account for nearly half (about 45%) of dementia cases worldwide. In the authors’ words, these cases could theoretically be prevented or delayed if the risks were removed (2024 Lancet Commission report).

The 14 factors, grouped by the stage of life where the evidence is strongest:

• Early life: less education.
• Midlife (roughly ages 40 to 65): hearing loss, high LDL (“bad”) cholesterol, depression, head injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, and heavy drinking.
• Later life: social isolation, air pollution, and untreated vision loss.

The two newest additions in 2024 were high LDL cholesterol and untreated vision loss. The factors linked with the largest share of cases were hearing loss and high LDL cholesterol (about 7% each), followed by less education and social isolation (about 5% each).

Our risk factors guide goes through all 14 in a table, with what the research links and what you can do.

What the 45% figure does not mean

It is easy to misread this number, so it helps to be precise:

• It is a population estimate. It describes dementia cases across the world, not your chances or your parent’s chances.
• It assumes cause and effect. The authors say they included only risk factors with convincing evidence, but that some links may be only partly causal. For example, depression in later life may sometimes be an early symptom of dementia rather than a cause.
• It does not guarantee anything for one person. The UCL summary notes that reducing risk works at the level of a population and does not guarantee that any individual will avoid dementia.
• The other half is not explained by these factors. Age, genes and causes scientists do not yet understand make up the rest.

What is the difference between “risk reduction” and “prevention”?

Risk reduction means lowering the odds. If a large group of people lower their blood pressure, fewer of them may develop dementia over many years than would have otherwise. Some individuals in that group will still develop it.

Prevention suggests stopping something from happening at all. For dementia, that is not something research can promise to anyone today.

Researchers also talk about delay. The Lancet Commission reports new evidence that lowering risk may push back when dementia starts and shorten the time a person spends living with ill health. Even a delay of a few years can matter a great deal to a person and their family.

On this site, we use “lower risk” and “linked with” on purpose. When you see a product, supplement or program promising to “prevent Alzheimer’s”, treat it with caution. The NIA advises checking with a doctor before trying any pill or treatment that promises to prevent Alzheimer’s, because such products may be unsafe, a waste of money, or both.

What have large trials found?

Observational studies (which watch what happens to people over time) can show links. Randomized trials, where people are assigned to a program or a comparison group by chance, are the stronger test. Here is what some of the best-known trials found.

FINGER (Finland)

The FINGER trial enrolled 1,260 adults aged 60 to 77 who were at higher risk of dementia. Half received a two-year program of diet advice, exercise, computer brain exercises and checks on heart and blood vessel health; the other half received general health advice. The program group did slightly better on a set of thinking tests, a small but statistically significant difference (FINGER trial in The Lancet). The trial measured test results, not dementia diagnoses.

US POINTER (United States)

US POINTER enrolled 2,111 adults aged 60 to 79 who were inactive, had a less healthy diet and had other risk factors. Both groups were encouraged to be more physically and mentally active, eat better, stay social and monitor heart health. One group got a structured, coached program; the other guided itself. Over two years, thinking test results improved in both groups, and slightly more in the structured group (US POINTER trial in JAMA). The authors say more follow-up is needed to know whether the difference matters in daily life. Because there was no “do nothing” group, the trial cannot say how much either program helped compared with no change at all.

SPRINT MIND (blood pressure)

SPRINT MIND studied 9,361 US adults aged 50 and older with high blood pressure. They were assigned to a lower blood pressure goal (top number under 120) or the standard goal (under 140). The lower goal significantly reduced mild cognitive impairment, a stage of memory and thinking problems that can come before dementia. For probable dementia, there were fewer cases in the lower-goal group, but the difference was not statistically significant. The trial stopped early and had fewer dementia cases than expected, so it may have been too small to answer that question (SPRINT MIND in JAMA).

What the reviews add up to

A 2021 Cochrane review pooled nine large trials of programs that tackle several risks at once, with more than 18,000 people. It found a small benefit on thinking tests, but no clear difference in how many people developed dementia in the two trials that measured it (Cochrane review of multi-domain interventions).

A 2017 review by the National Academies of Sciences, Engineering, and Medicine, summarized by the NIA, found “encouraging but inconclusive” evidence for three approaches: managing high blood pressure, increasing physical activity, and cognitive training.

Does it matter when you start?

The Lancet Commission’s advice is to lower risks as early as possible and keep them low for as long as possible: “the earlier, the better” and “the longer, the better.” It also says it is never too early or too late to reduce risk. Much of the evidence concerns midlife, roughly ages 40 to 65, but some factors, such as vision loss and social isolation, are later-life risks where action can still make sense.

The report says there is now stronger evidence that longer exposure to a risk has a bigger effect. For example, diabetes that starts in midlife appears to matter more than diabetes that starts later.

Is dementia risk the same for everyone?

No. The Commission found that people in low- and middle-income countries, people from minority groups and people with less money often carry more of these risks, so dementia tends to develop at a younger age. Many risks are tied to circumstances people did not choose, such as the quality of schooling they had as children, the air where they live, and whether healthy food is affordable and nearby.

That is why the Commission’s recommendations are aimed at governments as much as at individuals: good education for all children, cleaner air, measures to reduce smoking, less sugar and salt in food sold in stores and restaurants, and hearing aids for everyone who needs them. Individual effort matters, but so does the world people live in. It is one more reason not to blame anyone for a diagnosis.

What are the honest limits of this research?

• Dementia takes decades to develop, but most trials last two to five years. Measuring dementia itself, not just test results, needs very long and very large studies.
• Most trials measure thinking tests. A small improvement on a test does not necessarily mean fewer people will develop dementia or that daily life will be easier.
• Volunteers are often healthier and more educated than the general public. The Lancet Commission notes that most evidence still comes from high-income countries and that minority groups are under-represented.
• Some links run both ways. Being less active or less social can be an early effect of dementia, not only a cause.
• Diet trials have been disappointing so far. A three-year trial of the MIND diet found no significant difference in thinking compared with a control diet. See our diet guide.
• Brain games are not proven to prevent dementia. See our guide to brain games and dementia.
• Fasting has very limited human evidence, and it can be risky for older adults. See our fasting guide.

If someone did everything “right”, why did they still get dementia?

Because dementia is not simply the result of choices. The NIA says age is the biggest known risk factor for Alzheimer’s, and no one can change it. Genes play a part. And scientists do not yet fully understand what causes Alzheimer’s in most people. Even if every one of the 14 risk factors were removed, the Lancet Commission’s own estimate leaves more than half of cases unaccounted for.

So if you are caring for someone who exercised, ate well, never smoked and still developed dementia, nothing went wrong on their part, or yours. If you are living with dementia yourself, it is not your fault. Guilt is common among families, but it is not deserved. What matters now is comfort, connection and good days, and our activity ideas and caregiver self-care guide are a good place to start.

What steps can you talk over with a doctor?

These are the areas most often studied. They are worth raising at a checkup because most of them help heart health, mood and independence too, whatever their effect on dementia turns out to be.

1. Blood pressure. Ask what your numbers are and what goal suits you. The Lancet Commission suggests aiming for a top number of 130 or lower from around age 40, but the right target for an older adult depends on their overall health.
2. Hearing. Ask for a hearing test, and whether hearing aids would help. Our hearing guide explains the research.
3. Vision. Have regular eye exams and ask whether problems such as cataracts can be treated.
4. Cholesterol. Ask whether your LDL cholesterol should be checked and whether anything should change.
5. Blood sugar. If you have diabetes, ask how to manage it safely.
6. Mood. Depression is common and treatable. Tell your doctor if you have felt low or lost interest in things for more than a couple of weeks.
7. Smoking and alcohol. Ask about support to stop smoking and about safe limits for alcohol.
8. Movement. Ask what kind of activity is safe for you. Our exercise guide has ideas.
9. Head protection. Wear a helmet for cycling and contact sports, and ask about fall prevention.
10. Staying connected. Time with other people is part of a healthy life. See our guide to social connection, and sleep too.

Before changing medicines, diet, supplements, fasting or exercise, talk with your doctor first, especially if you have heart disease, diabetes, a history of falls, or are already living with dementia.

Talk with a doctor

If you notice memory or thinking changes that worry you, in yourself or someone else, make an appointment. The NIA notes that memory problems can have other causes, such as medicine side effects, thyroid problems, depression or low vitamin B12, and that some of these problems go away once the cause is treated. Our warning signs guide explains what to look out for.

Get urgent help for sudden changes: sudden confusion, weakness or numbness on one side, trouble speaking, or a severe headache can be signs of a stroke or another emergency. Call 911.

Where Golden Moments fits

Golden Moments makes simple shared activities, such as conversation cards, picture bingo and a calm breathing pause. They are for enjoyment and time together. They are not a treatment, and they do not prevent or slow dementia.