The short answer
The 2024 Lancet Commission named 14 potentially changeable dementia risk factors: less education, hearing loss, high LDL cholesterol, depression, head injury, inactivity, diabetes, smoking, high blood pressure, obesity, heavy drinking, social isolation, air pollution and untreated vision loss. Together they are linked with about 45% of cases worldwide, with no guarantee for any one person.
- The 14 factors span a whole life: one in early life, ten in midlife and three in later life.
- Hearing loss and high LDL cholesterol in midlife are each linked with about 7% of dementia cases worldwide, the largest shares of any single factor.
- These percentages are population estimates that assume cause and effect. Some links may be only partly causal.
- Age and genes, which no one can change, are major risk factors too. Lowering the 14 risks does not guarantee anyone avoids dementia.
- Most of the steps involved, such as checking blood pressure, hearing and vision, are good for health in other ways and worth discussing with a doctor.
On this page (7 sections)
A risk factor is something linked with a higher chance of developing a condition. It is not a cause in every case, and having one does not mean you will develop dementia. This page lists the 14 dementia risk factors that the 2024 Lancet Commission says can potentially be changed, what research links them with, and what you might talk over with a doctor.
For the bigger picture, including what large trials found, start with Can dementia be prevented? What the research says. This is general information, not medical advice; see our medical disclaimer.
What are the 14 risk factors for dementia?
The 2024 Lancet Commission, written by 27 dementia researchers, estimated that 14 potentially changeable risk factors together account for about 45% of dementia cases worldwide. The percentage for each factor below is the Commission’s estimate of the share of cases worldwide linked with it, rounded to whole numbers. The figures overlap, because many people have several risks at once, which is why they add up to 45% rather than more.
| Risk factor | Life stage | Share of cases | What research links | What you can do |
|---|---|---|---|---|
| Less education | Early life | 5% | Fewer years of schooling is linked with higher risk. Being mentally active in midlife also appears protective, even for people with little schooling. | Keep learning and doing mentally engaging things at any age: reading, hobbies, classes, games with others. |
| Hearing loss | Midlife | 7% | Untreated hearing loss is linked with higher risk. Studies that follow people over time link hearing aid use with lower risk. | Get your hearing tested. Ask whether hearing aids would help, and wear them if prescribed. Protect ears from loud noise. |
| High LDL cholesterol | Midlife (from about 40) | 7% | High LDL (“bad”) cholesterol in midlife is linked with higher risk. Observational studies link statin use with lower risk, but trials in later life have not shown this. | Ask your doctor whether your cholesterol should be checked and what, if anything, to do about it. |
| Depression | Midlife | 3% | Depression is linked with higher risk. In later life, depression can also be an early sign of dementia. | Tell a doctor about low mood or loss of interest lasting more than two weeks. Depression is treatable. |
| Traumatic brain injury | Midlife | 3% | Head injury at any age and from any source, including contact sports, is linked with higher risk. | Wear a helmet for cycling and contact sports. Ask about fall prevention. Rest and get checked after a head injury. |
| Physical inactivity | Midlife | 2% | People who exercise and play sport are less likely to develop dementia. Trial evidence is still limited. | Ask what activity is safe for you, and find something you enjoy. See our exercise guide. |
| Diabetes | Midlife | 2% | Diabetes, especially when it starts in midlife or lasts longer, is linked with higher risk. | Get blood sugar checked. If you have diabetes, work with your care team on managing it safely. |
| Smoking | Midlife | 2% | Smoking is linked with higher risk. Studies find ex-smokers do not carry the same raised risk as people who keep smoking. | Ask about support to stop. It is worth stopping at any age. |
| High blood pressure | Midlife | 2% | High blood pressure in midlife is linked with higher risk. Trials of blood pressure medicines suggest a modest lower risk of dementia or cognitive impairment. | Know your numbers. The Commission suggests a top number of 130 or lower from about age 40; ask what goal suits you. |
| Obesity | Midlife | 1% | Obesity in midlife is linked with higher risk, and it also raises the risk of diabetes. | Ask your doctor about a healthy weight for you. Older adults should not diet to lose weight without medical advice. |
| Excessive alcohol | Midlife | 1% | Heavy drinking is linked with higher risk. Cutting down from heavy drinking is linked with lower risk. | Ask what a safe limit is for you, especially with your medicines. |
| Social isolation | Later life | 5% | Infrequent social contact is linked with higher risk. | Keep in touch with people in ways you enjoy. See our social connection guide. |
| Air pollution | Later life | 3% | Living with more air pollution is linked with higher risk. Studies link cleaner air with lower risk. | Mostly a matter for public policy. Check local air quality alerts and limit time outdoors on very polluted days. |
| Untreated vision loss | Later life | 2% | Uncorrected vision problems are linked with higher risk. One large US study linked cataract surgery with lower risk. | Have regular eye exams. Ask whether problems such as cataracts can be treated. |
How should I read these percentages?
Carefully. The Commission’s own report makes several points worth keeping in mind:
- They describe populations, not people. University College London’s summary of the report notes that reducing risk works across a population and does not guarantee that any one person will avoid dementia.
- They assume cause and effect. The authors included only factors with convincing evidence, but say some links may be only partly causal.
- They are worldwide figures. Most data come from high-income countries, and the true share for any one country or community will differ.
- Small percentages can still matter. A factor linked with 2% of cases worldwide still affects a very large number of people.
Which risk factors were added in 2024?
The 2024 report added two factors to the 12 named in 2020:
- High LDL cholesterol in midlife, linked with about 7% of cases.
- Untreated vision loss in later life, linked with about 2% of cases.
What risk factors cannot be changed?
The National Institute on Aging says age is the biggest known risk factor for Alzheimer’s, and no one can change it. Genes also play a part; one well-known gene that influences Alzheimer’s risk is called APOE. The NIA adds that scientists do not yet fully understand what causes Alzheimer’s in most people. The Lancet Commission notes that the potentially changeable risks can be lowered whatever a person’s genetic risk.
Because age and genes play such a large part, many people who have none of the 14 risk factors still develop dementia. That is not anyone’s fault.
What does the trial evidence say about changing these risks?
Linking a risk factor with dementia is not the same as proving that changing it lowers dementia risk. A few examples of where the trial evidence stands:
- Blood pressure. In the SPRINT MIND trial, a lower blood pressure goal significantly reduced mild cognitive impairment. It did not significantly reduce probable dementia, though the trial may have been too small to show that (SPRINT MIND in JAMA).
- Hearing aids. The Lancet Commission describes a three-year hearing aid trial that found no overall effect on thinking, but a benefit in a subgroup of people at higher risk. Studies that follow people over time link hearing aid use with lower risk. Our hearing guide has more.
- Physical activity. The National Institute on Aging says there is not enough clinical trial evidence to conclude that exercise can prevent or slow mild cognitive impairment or Alzheimer’s, though some studies suggest it may help with age-related decline (NIA on preventing Alzheimer’s).
Long trials that wait for dementia to develop are slow and expensive, so for many factors the best evidence will continue to come from studies that follow people over years. That evidence is useful, but it is weaker than a trial.
What about sleep and diet?
The Commission reviewed sleep and diet but did not add them to the list, because the evidence was not strong or consistent enough. Our guides to sleep and diet explain what is known.
Talk with a doctor
A yearly checkup is a good time to raise these topics. You could bring this list and ask:
- What are my blood pressure, blood sugar and cholesterol numbers, and do any need attention?
- Should I have my hearing and eyes checked?
- Is the activity I do safe and enough for me?
- Could any of my medicines affect memory or thinking?
Before changing medicines, diet, fasting, exercise or supplements, talk with a doctor first. If you or someone you care for has sudden confusion, weakness on one side, or trouble speaking, call 911.
Common questions
What are the 14 modifiable risk factors for dementia?
The 2024 Lancet Commission named less education, hearing loss, high LDL cholesterol, depression, traumatic brain injury, physical inactivity, diabetes, smoking, high blood pressure, obesity, excessive alcohol, social isolation, air pollution and untreated vision loss. Together they are linked with nearly half of dementia cases worldwide.
Which dementia risk factor matters most?
Across the world's population, the Commission estimated that hearing loss and high LDL cholesterol in midlife are each linked with about 7% of cases, followed by less education and social isolation at about 5% each. Which factors matter most for one person depends on their own health, so a doctor is the best guide.
Are the two new risk factors added in 2024?
Yes. The 2024 report added high LDL (bad) cholesterol in midlife and untreated vision loss in later life to the 12 factors named in 2020. The Commission linked them with about 7% and 2% of cases respectively.
Is age a modifiable risk factor?
No. Age is the biggest known risk factor for Alzheimer's disease, and it cannot be changed. Genes also play a part. The 14 factors on this page are the ones research suggests can potentially be changed.
Sources
We link to the organizations and studies this page relies on. Each was checked when the page was updated.
- Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission · The Lancet
- Nearly half of dementia cases could be prevented or delayed by tackling 14 risk factors · University College London
- Preventing Alzheimer's Disease: What Do We Know? · National Institute on Aging
- What Causes Alzheimer's Disease? · National Institute on Aging
- Effect of Intensive vs Standard Blood Pressure Control on Probable Dementia: A Randomized Clinical Trial (SPRINT MIND) · JAMA (via PubMed)