2024Lancet
Livingston et al.
International commission
14 changeable risk factors account for about 45% of dementia. Hearing loss and high LDL cholesterol in midlife are the biggest, at 7% each.
Find on PubMed ↗Research library · Mind & mood
Brain health: keeping your memory sharp
Nearly half of dementia cases worldwide could be prevented or delayed by tackling 14 risk factors through life, from hearing loss to high cholesterol. What protects your heart also protects your brain.
Good evidenceUpdated Oct 2026 · 4 new studies45%of dementia linked to 14 changeable risk factorsLivingston 2024, Lancet Commission
−50%dementia risk at about 9,800 steps a day; 3,800 steps cut it by 25%del Pozo Cruz 2022, JAMA Neurol, 78,430 adults
−20%new dementia diagnoses over 7 years after the shingles vaccineEyting 2025, Nature, natural experiment in Wales
01
The basics
Building your brain's reserve
Your brain uses about a fifth of your body's energy and depends on a steady blood supply. Damage to small blood vessels, from high blood pressure, diabetes and smoking, is one of the biggest drivers of memory decline.
Alzheimer's disease involves build-ups of proteins called amyloid and tau. During deep sleep, the brain's glymphatic system flushes waste, including amyloid, so poor sleep may speed things up.
People with more cognitive reserve, built through education, challenging work, social life, exercise and good hearing, can carry the same brain changes with fewer symptoms. Hearing loss matters because a brain straining to hear has less capacity left for thinking and memory.
14 risk factors for dementia
Share of dementia worldwide linked to each factor (Lancet Commission 2024). Together they account for about 45%.
02
How it works
What keeps a brain healthy
1
Good blood flow
Healthy blood pressure, sugar and cholesterol protect tiny brain vessels.
2
Deep sleep cleans
The glymphatic system clears waste while you sleep.
3
Use it
Learning, social life and good hearing keep circuits active.
4
More reserve
A well-connected brain copes with ageing for longer.
03
Measure it
Checks that protect your brain
- Hearing test: from 50, or sooner if you struggle in noisy rooms. Untreated hearing loss is the largest single risk factor.
- Eye test: untreated vision loss was added as a new risk factor in 2024.
- Blood pressure and LDL cholesterol: keep top blood pressure under 130 from midlife and treat high LDL.
- Memory worries? A doctor can run a short test such as the MoCA. Low B12, low thyroid, depression and medicines can all cause reversible memory problems.
04
What the research says
The key studies
2022JAMA Neurology
del Pozo Cruz et al.
78,430 adults, wrist trackers
About 9,800 steps a day was linked to 50% lower dementia risk over 7 years; 3,800 steps to 25% lower. Brisk steps mattered most.
Find on PubMed ↗2025Nature
Eyting et al.
280,000+ older adults in Wales
A birth-date cut-off decided who got the shingles vaccine. Those who got it were about 20% less likely to be diagnosed with dementia over 7 years.
Find on PubMed ↗2015Lancet
Ngandu et al. (FINGER)
1,260 older adults, 2 years
A combined programme of healthy diet, exercise, brain training and heart checks improved thinking scores compared with general advice.
Find on PubMed ↗2023Lancet
Lin et al. (ACHIEVE)
977 older adults with hearing loss
Hearing aids and support slowed cognitive decline by 48% over 3 years in people already at higher risk.
Find on PubMed ↗2025JAMA
Baker et al. (US POINTER)
2,111 older adults at risk
A structured 2-year lifestyle programme (exercise, MIND diet, brain training, health checks) improved thinking more than a self-guided version.
Find on PubMed ↗05
New in 2025–26
What the newest research adds
Evidence that the shingles vaccine protects the brain keeps growing, with a second country now showing fewer dementia diagnoses and a 2025 study suggesting it may even slow the disease. Blood tests for Alzheimer's have arrived, but experts say they are for people with memory symptoms seen by specialists, not for screening healthy people.
The new studies, in order
Every study added to this page since January 2025. Green rings are the strongest evidence: large trials or meta-analyses.
How well the first Alzheimer's blood test agrees
Lumipulse pTau217, FDA-cleared May 2025, tested in 499 adults with memory problems. How often its results matched brain scans or spinal fluid tests.
NewApr 2025JAMA
Pomirchy et al.
101,219 older adults in Australia, 7.4 years
Using Australia's age cut-off for free shingles vaccination as a natural experiment, being eligible lowered the chance of a new dementia diagnosis by 1.8 percentage points over about 7 years. This backs up similar findings from Wales.
Good evidenceRead the source ↗
NewDec 2025Cell
Xie et al.
Over 300,000 people in Wales, 2013 to 2022
Shingles vaccination reduced new diagnoses of mild memory problems by about 3 percentage points over 9 years. Among people already living with dementia, vaccinated people were much less likely to die from dementia, and the effect was stronger in women.
Good evidenceRead the source ↗
NewMay 2025FDA clearance
US FDA (Lumipulse pTau217 test)
499 blood samples from adults with memory problems
The first blood test to help diagnose Alzheimer's was cleared for adults 55 and over with symptoms. Positive results matched brain scans or spinal fluid tests 91.7% of the time and negative results 97.3% of the time.
Good evidenceRead the source ↗
NewJul 2025Alzheimer's & Dementia
Alzheimer's Association guideline
Clinical practice guideline
Blood tests should only be used for people with real memory or thinking problems, after a full assessment in a specialist memory service. Tests need at least 90% sensitivity, and many tests on the market do not yet meet the bar.
Good evidenceRead the source ↗
What this changes for you
If you're eligible for the shingles vaccine, get it: it prevents shingles and may protect memory too. Alzheimer's blood tests are for people with symptoms, through a memory clinic, not for check-ups in healthy people.
06
Take action
A brain-protection plan
The earlier you start, the bigger the effect, but it's never too late.
- 1
Check your hearing
Get tested and wear hearing aids if you need them. They're now available over the counter in many countries.
- 2
Walk briskly most days
Work up toward 8,000–10,000 steps, with some at a purposeful pace.
- 3
Treat blood pressure and LDL
Keeping both in range protects your brain's blood vessels.
- 4
Sleep 7–8 hours
Get snoring or gasping checked for sleep apnoea.
- 5
Learn hard new things
A language, instrument or dance challenges the brain more than repeat puzzles.
- 6
Helmets and vaccines
Protect your head in sport and cycling, and ask about the shingles vaccine after 50.
07
Myth or fact
Common myths, checked
✕ MythBrain-training apps prevent dementia.
✓ FactMost apps make you better at the app. Real-world learning and social challenge have stronger evidence.
✕ MythDementia is a normal part of ageing.
✓ FactSome slowing is normal; dementia isn't. Many people reach 90+ with sharp minds.
✕ MythIt's all in your genes.
✓ FactThe APOE4 gene raises risk, but people who carry it still benefit from lifestyle changes.
✕ MythCrosswords are enough.
✓ FactThey help a little. Physical activity, hearing and heart health matter far more.
08
Questions
Frequently asked
Should I get tested for APOE4?
It doesn't change prevention advice, and results can cause worry. Talk to a doctor or genetic counsellor first.
Are memory slips normal?
Forgetting a name and remembering later is normal. Getting lost in familiar places or repeating questions isn't. See a doctor.
Do supplements help memory?
No supplement prevents dementia. A daily multivitamin modestly slowed memory ageing in older adults in one set of trials.
09
Test yourself
True, partly true or myth?
Read each claim and pick an answer: the card flips to show the verdict and why. Not sure? Use “Just reveal”.
Card № 01True or myth?
About 45% of dementia cases may be preventable or delayed by tackling 14 risk factors.
True
About 45% of dementia cases may be preventable or delayed by tackling 14 risk factors.
The 2024 Lancet Commission added high LDL cholesterol and untreated vision loss to its list.
Card № 02True or myth?
Treating hearing loss may lower dementia risk.
True
Treating hearing loss may lower dementia risk.
Hearing loss is one of the largest risk factors; the ACHIEVE trial suggested hearing aids slowed decline in higher-risk people.
Card № 03True or myth?
Brain-training apps make you smarter in general.
Myth
Brain-training apps make you smarter in general.
You get better at the games, but improvements rarely transfer to everyday memory or intelligence.
Card № 04True or myth?
Aerobic exercise can increase the size of the hippocampus.
True
Aerobic exercise can increase the size of the hippocampus.
Erickson 2011: a year of walking grew the memory centre by about 2% in older adults, reversing 1–2 years of loss.
Card № 05True or myth?
We only use 10% of our brain.
Myth
We only use 10% of our brain.
Brain scans show activity across almost all of it, just not all at once.
Card № 06True or myth?
Memory naturally declines a lot with age.
Partly true
Memory naturally declines a lot with age.
Some slowing is normal, but large memory losses are not. Many people keep sharp minds into old age.
Card № 07True or myth?
Controlling blood pressure in midlife protects the brain.
True
Controlling blood pressure in midlife protects the brain.
SPRINT MIND found tighter blood pressure control lowered the risk of mild cognitive impairment.
Card № 08True or myth?
Learning new, challenging skills builds 'cognitive reserve'.
True
Learning new, challenging skills builds 'cognitive reserve'.
More education and mentally demanding activities are linked to resisting dementia symptoms longer.
Card № 09True or myth?
Crosswords prevent dementia.
Partly true
Crosswords prevent dementia.
Mentally active people tend to have lower risk, but it's unclear whether puzzles themselves cause the benefit.
Card № 10True or myth?
You can't grow new brain cells as an adult.
Myth
You can't grow new brain cells as an adult.
Evidence suggests new neurons still form in the adult hippocampus, though how much in humans is debated.
Nothing here yet. Try another filter.
10
Sources
References and related topics
- Livingston et al. (2024). Lancet. International commission. PubMed ↗
- del Pozo Cruz et al. (2022). JAMA Neurology. 78,430 adults, wrist trackers. PubMed ↗
- Eyting et al. (2025). Nature. 280,000+ older adults in Wales. PubMed ↗
- Ngandu et al. (FINGER) (2015). Lancet. 1,260 older adults, 2 years. PubMed ↗
- Lin et al. (ACHIEVE) (2023). Lancet. 977 older adults with hearing loss. PubMed ↗
- Baker et al. (US POINTER) (2025). JAMA. 2,111 older adults at risk. PubMed ↗
- Pomirchy et al. (2025). JAMA. 101,219 older adults in Australia, 7.4 years. Source ↗
- Xie et al. (2025). Cell. Over 300,000 people in Wales, 2013 to 2022. Source ↗
- US FDA (Lumipulse pTau217 test) (2025). FDA clearance. 499 blood samples from adults with memory problems. Source ↗
- Alzheimer's Association guideline (2025). Alzheimer's & Dementia. Clinical practice guideline. Source ↗