The WHO says nearly half of dementia cases trace to risks people can change

The World Health Organization has updated its global guidance on preventing dementia, concluding that up to 45% of cases can be traced to a set of risk factors that people, health systems and governments can influence over a lifetime. The figure does not mean any one person can cut their own dementia odds by nearly half through lifestyle changes alone; it is a population-level estimate of how much of the overall disease burden could theoretically be avoided if those risk factors were eliminated across an entire population. Even so, WHO officials say the guidelines translate years of accumulated research into concrete steps that countries can act on now.

A Second Edition Updates Guidance WHO First Issued in 2019

The updated guidelines, released on July 15, 2026, mark the second edition of WHO’s recommendations on reducing the risk of cognitive decline and dementia, reflecting what the agency describes as significant growth in the evidence base since the first version. “We know more today than ever before about what drives dementia risk, and these guidelines translate that knowledge into action,” said WHO Director-General Dr. Tedros Adhanom Ghebreyesus, adding that countries “now have clear, evidence-based recommendations they can put into practice immediately to protect people’s cognitive health.”

Tobacco, Alcohol, Air Pollution and Isolation Head the Modifiable List

The guidelines identify a broad set of behaviors and exposures tied to dementia risk, including tobacco use, harmful alcohol consumption, physical inactivity, social isolation and exposure to air pollution, the last of which is a new addition to this edition. WHO’s separate fact sheet on dementia adds low educational attainment and poor sleep to that list of lifestyle-linked factors, describing dementia risk as something that “accumulates across the life course,” with certain factors mattering more at particular ages than others.

Cardiometabolic Conditions Such as Hypertension and Diabetes Also Factor In

Beyond behavior, the guidelines emphasize managing existing medical conditions that raise dementia risk, including high blood pressure, high blood sugar associated with diabetes, obesity, depression, and hearing or vision loss. WHO now recommends that hearing aids may be offered as part of a broader risk-reduction strategy for people with hearing loss, alongside standard treatment for cardiometabolic conditions such as blood pressure and cholesterol medication.

Cognitive Training and Social Engagement Are Recommended for At-Risk Adults

For adults with normal cognition or mild cognitive impairment, the guidelines recommend cognitive training, cognitive stimulation and structured engagement in social activities as interventions that can help protect brain health over time. These recommendations sit alongside, rather than in place of, the behavioral and medical measures aimed at noncommunicable disease risk factors.

Vitamin and Omega-3 Supplements Are Explicitly Not Recommended

One notable exclusion from the guidance: WHO does not recommend supplementing with vitamins B or E, omega-3 polyunsaturated fatty acids, or general multivitamins and minerals as a way to reduce dementia risk in people who do not have a diagnosed deficiency. The agency cites a lack of evidence that any potential benefit would outweigh the possibility of unexpected harm, a distinction that separates supplementation for a confirmed medical deficiency from taking supplements purely as a preventive measure against cognitive decline.

Dementia Already Affects 57 Million People and Costs $1.3 Trillion a Year

The scale of the problem underpins the urgency behind the update. WHO estimates that 57 million people were living with dementia worldwide as of 2021, more than 60% of them in low- and middle-income countries, with nearly 10 million new cases diagnosed every year. Alzheimer disease is the most common underlying cause, accounting for an estimated 60% to 70% of cases, though vascular dementia, dementia with Lewy bodies and frontotemporal degeneration also contribute. Dementia is currently the seventh leading cause of death globally and a leading cause of disability and dependency among older adults. The condition cost the global economy an estimated $1.3 trillion in 2019, with roughly half of that figure attributable to unpaid care provided by family members and friends, who WHO says provide an average of five hours of care and supervision a day. Women disproportionately bear both the disease burden and the caregiving load tied to dementia, according to WHO, experiencing higher rates of disability and death from the condition while also providing about 70% of all caregiving hours worldwide. The agency also notes that while age remains the strongest known risk factor, dementia is not exclusive to old age: young-onset dementia, in which symptoms begin before age 65, accounts for up to 9% of cases. Coverage of the guidelines has framed the 45% figure as a rare piece of good news in a field with no approved cure, since it points to concrete, largely low-cost interventions rather than a still-elusive treatment breakthrough.

WHO frames the new document as a tool for health systems and policymakers as much as for individuals, calling for stronger integration of noncommunicable disease programs, mental health services and brain health initiatives at the national level. The guidelines sit alongside WHO’s broader Global Action Plan on the public health response to dementia, first endorsed by the World Health Assembly in 2017 and since extended through 2031, which the agency tracks through a Global Dementia Observatory covering 35 indicators across national health systems. For any one person, the guidelines translate into familiar advice: stay physically active, avoid tobacco, moderate alcohol use, protect hearing, manage blood pressure and blood sugar, and stay socially connected. None of those steps guarantees an individual outcome, since dementia can still develop even when every modifiable factor is addressed, and age itself remains the single strongest known risk factor. What the population-level estimate captures instead is the scale of risk that is, in principle, avoidable if those factors were addressed broadly and consistently across society.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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