Dementia awareness: what is known

How many people, and who

The figures are WHO’s, from the dementia fact sheet published 26 October 2026. 57 million people were living with dementia worldwide in 2021; over 60% of them in low- and middle-income countries; nearly 10 million new cases every year. Alzheimer disease is the most common form, accounting for 60–70% of cases. Dementia is the fifth leading cause of death and a major cause of disability and dependency among older people. The cost was US$1.3 trillion globally in 2019, with about 50% attributable to informal carers — who provide an average of 5 hours of care a day — and women providing 70% of care hours. The cost figure is the point that the carer section below returns to: dementia is a condition of families as much as of individuals.

Dementia is not inevitable ageing

“Although more common after age 65, dementia is not an inevitable part of ageing.” That sentence, from WHO’s fact sheet, is the page’s central correction. Dementia risk accumulates across the life course, and some risk factors have a greater impact at particular stages of life. The risk factors WHO names include high blood pressure, diabetes, overweight and obesity, depression, hearing and vision loss, smoking, harmful alcohol use, physical inactivity, social isolation, low education, and air pollution. WHO describes the course of dementia in stages — early, middle and late — with changing abilities at each stage. This page describes the stages in general terms only, and it does not list early signs as a self-check: a signs list would edge toward self-diagnosis, which is outside this site’s scope. For a personal question, the route is a health professional.

Can dementia risk be reduced

Up to 45% of dementia risk could be prevented or delayed by addressing modifiable risk factors, according to WHO’s updated guidelines of 15 July 2026. The figure is a theoretical maximum — what would happen if all targeted risks were optimally managed or eliminated across the life course — not a promise for any individual. The guidelines group the interventions in three areas: healthy behaviours and lifestyle, management of medical conditions (particularly hypertension, diabetes and high cholesterol), and reducing exposure to environmental factors, with air pollution added as a recommended strategy for the first time. The guidelines also recommend against routine vitamin B, vitamin E, omega-3 and multivitamin supplements purely to prevent cognitive decline, unless a specific deficiency is diagnosed. The risk factors are the same ones that shape healthy ageing generally — which is why this page links to the healthy ageing guide rather than repeating it.

Young-onset dementia

Young-onset dementia accounts for up to 9% of cases (WHO, 26 October 2026). It is dementia that begins before age 65 — and it is the part of the picture most often missed, because dementia is assumed to be a condition of old age. A person with young-onset dementia may still be working, still raising children, and still paying a mortgage when the condition begins, and the services built for older people may not fit. This subsection names young-onset dementia and its share; it does not describe its causes or its course in detail, because the WHO fact sheet treats it as a share of the whole, and this page follows the fact sheet.

Carer support and iSupport

This subsection is the home for the gap the research found. There is no cure for dementia, but a lot can be done to support people living with dementia and those who care for them (WHO). WHO runs iSupport, a training and support programme for carers of people with dementia — the fact sheet names it, and this page links to it rather than reproducing it. Informal carers carry about half the global cost of dementia and an average of 5 hours of care a day, and women provide 70% of care hours. Carer support is therefore not an add-on to dementia care; it is half of it. The WHO Global Dementia Observatory tracks 35 indicators of national dementia responses, and the Global action plan on dementia has been extended to 2031. For a personal question about caring for someone with dementia, the routes are a clinician, local services, and the carer programmes WHO links to — not this page.

Frequently asked questions