Yes—but only at the population level. WHO says up to 45% of dementia risk is attributable to potentially modifiable factors, not that every person can reduce their risk by 45%.
Dementia progressively affects memory, thinking, and daily function. WHO reports that 57 million people lived with dementia in 2021, with Alzheimer disease accounting for an estimated 60–70% of cases. WHO's dementia fact sheet.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- What does the 45% estimate mean?
- Which risk factors are included?
- How strong is the evidence?
- What can an individual do?
- What should readers not assume?
What does the 45% estimate mean?
The figure comes from a weighted population-attributable fraction. This statistical model estimates the share of dementia cases associated with selected risk factors across a population. The 2024 Lancet Commission calculated a combined fraction of 45.3% for 14 potentially modifiable factors.
The estimate assumes these factors help cause dementia and considers how common they are and how strongly they are associated with risk. The 2024 Lancet Commission report "Potentially modifiable" does not mean completely avoidable. Some factors are difficult to change, while others depend on health care, income, education, working conditions, neighborhood safety, or environmental policy.
Which risk factors are included?
The estimate covers factors that can arise from early life through older age: Hearing loss and high LDL cholesterol had the largest modelled shares, at 7% each. Less education and social isolation accounted for 5% each.
High LDL cholesterol and untreated vision loss were new additions in the 2024 update. These percentages cannot be added as though each factor acts independently. Risks overlap: one person may have hypertension, diabetes, inactivity, and social isolation at the same time.
- Less education
- Hearing loss
- High LDL cholesterol
- Depression
- Head injury
How strong is the evidence?
The 45% figure combines observational research and statistical assumptions. It is not the result of a trial in which one group eliminated all 14 factors and developed 45% less dementia. The Commission assumes that the associations are causal. It also notes that prevalence data come disproportionately from high-income countries and that evidence about how risks cluster across countries remains scarce. Its authors explicitly caution that population-wide risk reduction cannot guarantee that an individual will avoid dementia.
Clinical trials also show why the headline needs restraint. SPRINT-MIND studied 9,361 adults aged 50 or older who had hypertension but no diabetes or previous stroke. Intensive blood-pressure treatment did not significantly reduce probable dementia, although it reduced mild cognitive impairment, or MCI, with a hazard ratio of 0.81. The SPRINT-MIND trial in JAMA That result does not make blood-pressure control unimportant. It shows that improving one risk factor may affect some cognitive outcomes without producing a clear reduction in diagnosed dementia during a particular trial.
What can an individual do?
Risk reduction is best treated as a long-term direction, not a promise. A practical starting point is to identify relevant factors and address them with appropriate support: WHO's updated guidance presents these as life-course actions supported by health systems and public policy—not simply matters of personal willpower.
Its recommendations also address access to hearing care, cardiometabolic treatment, education, and cleaner air. WHO's risk-reduction guideline, second edition.
- Be physically active.
- Stop smoking and avoid harmful alcohol use.
- Follow a healthy diet.
- Ask about managing blood pressure, LDL cholesterol, diabetes, and obesity.
- Seek care for depression.
What should readers not assume?
A lower-risk lifestyle cannot rule out dementia, and having several risk factors does not mean dementia is inevitable. The estimate describes what might be preventable or delayed across groups if causal risks were reduced; it does not calculate anyone's personal percentage.
WHO also does not recommend vitamin B, vitamin E, omega-3, or multivitamin and mineral supplements solely to reduce dementia risk when no deficiency has been diagnosed. The organization found insufficient evidence that their benefits outweigh potential harms. WHO's 2026 guideline announcement.
