Who is affected?
Contrary to popular belief, Alzheimer’s disease is not a normal part of ageing, although it primarily affects people over the age of 65. The risk increases significantly with age, but the disease can also develop before the age of 65. In rare cases, symptoms may begin before the age of 40.
Age is the strongest known risk factor for Alzheimer’s disease. However, growing older does not mean that a person will inevitably develop the condition.
According to published estimates, Alzheimer’s disease affects approximately 0.5% of people under the age of 65. Its prevalence increases with age, reaching an estimated 2–4% among people over the age of 65 and around 15% among those over the age of 80.
Life expectancy for people living with Alzheimer’s disease varies considerably, depending on factors such as age at diagnosis, overall health and the progression of the disease. Survival is often estimated at around 8–12 years from the onset of symptoms, although it can be shorter or considerably longer.
Research suggests that the brain changes associated with Alzheimer’s disease can begin 10–15 years or more before symptoms become apparent.
Key Facts and Figures on Alzheimer’s Disease and Dementia Worldwide
According to the World Health Organization (WHO) and Alzheimer’s Disease International (ADI):
> More than 55 million people were estimated to be living with dementia worldwide in 2020. The WHO’s estimates indicate that this figure had risen to approximately 57 million in 2021.
> Alzheimer’s disease accounts for an estimated 60–70% of dementia cases, making it the most common cause of dementia.
> Nearly 10 million new cases of dementia arise each year worldwide — equivalent to one new case every three seconds.
> The number of people living with dementia is projected to rise to 78 million by 2030 and 139 million by 2050.
> The increase is expected to be particularly significant in low- and middle-income countries, where population ageing and demographic changes are contributing to a growing number of cases.
> Women account for a greater proportion of people living with dementia, partly because they tend to live longer than men.
Sources: World Health Organization (WHO); Alzheimer’s Disease International (ADI).
Alzheimer’s Disease Affects the Whole Family
Behind every person living with Alzheimer’s disease is often a family also affected by the condition. A spouse, child or other family member may take on the role of an informal carer, providing daily care and support to their loved one.
Supporting carers is essential to help them cope with the demands of caring, reduce stress and prevent exhaustion.
Note: These figures are estimates drawn from major international studies and reports. Prevalence and projections vary according to the source, methodology and year of publication.