Alzheimer’s is the leading cause of dementia, one of the most common serious illnesses of later life, and the number of people living with it is set to roughly triple in a generation. Most of that rise reflects longer lives and growing older populations, not a rising chance of dementia at any given age. Meanwhile, most people living with dementia today have never been told they have it.
How Many People Have Dementia Worldwide
Dementia is a decline in memory and thinking that is serious enough to disrupt daily life. Alzheimer’s disease causes about 60 to 70% of cases. Vascular dementia and Lewy body dementia are other common causes, and many people have more than one cause at once. Global statistics usually count all dementias together. About 57.4 million people worldwide were living with dementia in 2019.1PubMed Central. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019 By 2050 the total is projected to reach about 152.8 million.2PubMed Central. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019
If you compare people of the same age, the share who have dementia is expected to stay almost unchanged between 2019 and 2050.3PubMed Central. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019 So the growth comes from more people reaching the ages when dementia is common. The fastest growth in older populations is happening in China, India and their neighbours in South Asia and the Western Pacific.4Alzheimer’s Disease International. ADI – Dementia statistics
That is why “cases tripling” does not mean your own risk is tripling. If you see 55 million in one report and 57 million in another, the difference usually comes from counting different years.
How Common Alzheimer’s Is at Each Age
- Ages 65 to 74: about 5% have Alzheimer’s dementia.5BrightFocus Foundation. Facts & Figures – Alzheimer’s Disease
- Ages 75 to 84: about 13%.6BrightFocus Foundation. Facts & Figures – Alzheimer’s Disease
- Ages 85 and older: about 33%, or 1 in 3.7BrightFocus Foundation. Facts & Figures – Alzheimer’s Disease
Across all U.S. adults aged 65 and older, more than 1 in 9 (11.3%) have Alzheimer’s.8UsAgainstAlzheimer’s. The Alzheimer’s Disease Crisis – By the Numbers Beyond age 65, the number of people with the disease doubles about every five years of age.9BrightFocus Foundation. Facts & Figures – Alzheimer’s Disease These figures describe a group, not a forecast for one person. Memory problems at any age should still be checked by a doctor.
Alzheimer’s can also begin before 65, and it is often missed in younger adults because the early symptoms can be unusual.10PubMed Central. Global, Regional, and National Burden of Early‐Onset Alzheimer’s Disease and Other Dementias in Young Adults Aged 40–64 Years, 1990–2021: A Population‐Based Study In younger people it can be mistaken for stress, depression or burnout, and early signs may involve language, vision or behaviour rather than memory. A delayed diagnosis can mean later treatment and worse outcomes.11PubMed Central. Global, Regional, and National Burden of Early‐Onset Alzheimer’s Disease and Other Dementias in Young Adults Aged 40–64 Years, 1990–2021: A Population‐Based Study
Why Most Cases Go Undiagnosed
About 75% of people with dementia worldwide have not been diagnosed, or roughly 41 million people.12Dementia Matters. Global Challenges in Dementia Diagnosis: A Deep Dive into ADI’s World Alzheimer’s Report 2021 In some low-income countries, up to 90% go undiagnosed.13BrightFocus Foundation. Facts & Figures – Alzheimer’s Disease
Several things stand in the way. Low awareness of early symptoms, fear of stigma, and cultural views of the condition all delay diagnosis.14Canadian Journal of Health Technologies. Health System Readiness for Disease-Modifying Therapies for Alzheimer Disease Every world region reports too few neurologists and other specialists who can assess dementia.15PubMed Central. Facilitators and Barriers to Dementia Assessment and Diagnosis: Perspectives From Dementia Experts Within a Global Health Context Even in the United States, 34% to 59% of adults aged 65 and older live in areas with too few dementia specialists.16PubMed Central. Geographic variation in shortfalls of dementia specialists in the United States
Occasional forgetfulness is common with age. Getting lost in a familiar place or struggling with daily tasks is not normal ageing. Families often notice changes before the person does, and writing down specific examples gives the doctor something concrete to work with.
A diagnosis is worth seeking for several reasons. It can rule out treatable causes of memory problems, such as thyroid disease or vitamin B12 deficiency. It opens access to support services and to newer treatments, and it gives the family time to plan for money and care. Starting with a family doctor is the usual first step.
Where Dementia Is Rising Fastest
About 60% of people with dementia live in low- and middle-income countries.17Alzheimer’s Disease International. ADI – Dementia statistics By 2050 that share is expected to rise to about 71%, because populations are ageing fastest in these countries.18Alzheimer’s Disease International. ADI – Dementia statistics Yet these are also the places with the fewest specialists and the lowest diagnosis rates.19PubMed Central. Facilitators and Barriers to Dementia Assessment and Diagnosis: Perspectives From Dementia Experts Within a Global Health Context Where specialists are scarce, training family doctors to recognise and manage dementia helps fill the gap.
Who Is Most at Risk Women Ethnic Groups and Genes
Women have about a 12% higher risk of developing dementia than men, with the gap largest in lower-income countries.20PubMed Central. Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium Women also live longer on average, which adds to the number of women with dementia.
In one large U.S. study, African Americans had the highest rate of new dementia cases and Filipino Americans the lowest.21PubMed Central. Risk of Alzheimer’s disease and related dementia by sex and race/ethnicity: The Multiethnic Cohort Study The differences shrank once education, heart disease and diabetes were taken into account.22PubMed Central. Risk of Alzheimer’s disease and related dementia by sex and race/ethnicity: The Multiethnic Cohort Study So much of the gap reflects health and life circumstances rather than ethnicity itself.
APOE4 is a common gene variant that raises the risk of Alzheimer’s. Carrying one copy raises the odds about 3.5 times in White people, 4.5 times in East Asian people, and about 2 times in Black and Hispanic people.23JAMA Neurology. APOE Genotype and Alzheimer Disease Risk Across Age, Sex, and Population Ancestry Almost all adults with Down syndrome show the brain changes of Alzheimer’s by age 40.24PubMed Central. Dementia in Down syndrome: unique insights for Alzheimer disease research
Carrying the APOE4 gene variant raises risk but does not mean you will get Alzheimer’s, and many people with Alzheimer’s do not carry it. If you are thinking about testing, talk with a genetic counsellor first. The result rarely changes the everyday steps that lower risk.
Families caring for an adult with Down syndrome can watch from midlife onward for changes in skills or behaviour, which can look different from typical memory loss. It is reasonable to ask the doctor about regular memory checks from around age 40, and to plan ahead for future care needs.
How Many Cases Could Be Prevented
Some risks can be changed, such as high blood pressure, smoking, inactivity and diabetes. Seven of these together, which are low education, midlife high blood pressure, midlife obesity, smoking, inactivity, depression and diabetes, are linked to about a third of dementia cases.25PubMed Central. Population attributable fractions of modifiable risk factors for dementia: a systematic review and meta-analysis Under other ways of counting, the share can be estimated as high as 55%.26PubMed Central. Population attributable fractions of modifiable risk factors for dementia: a systematic review and meta-analysis In one real-world population, about 40% of cases were linked to preventable illnesses.27PubMed Central. Estimating the potential for dementia prevention through modifiable risk factors elimination in the real-world setting: a population-based study
Long-term exposure to fine-particle air pollution, especially from traffic and burning fossil fuels, is linked to higher dementia risk.28PubMed Central. Incident dementia and long-term exposure to constituents of fine particle air pollution: A national cohort study in the United States In one U.S. study, each small rise in 10-year average fine-particle exposure was linked to a 16% higher risk of dementia.29PubMed Central. Fine Particulate Matter and Dementia Incidence in the Adult Changes in Thought Study
Several steps target these changeable risks. Have your blood pressure checked and controlled starting in midlife. Stay physically active most days, and stop smoking, which helps at any age. Get depression and diabetes treated, and reduce time spent next to heavy traffic when you can.
“Preventable” describes risk across a population. These steps lower risk but don’t guarantee anything for one person, and age and genes still matter. It is not too late to make changes in later life, and the same habits protect heart health.
What Dementia Costs Families and Countries
Dementia cost the world about $1.3 trillion in 2019, or about $23,800 per person with dementia.30PubMed Central. The worldwide costs of dementia in 2019 Half of that cost was unpaid care from family and friends, 34% was social care such as care homes, and only 16% was medical care.31PubMed Central. The worldwide costs of dementia in 2019
Family members gave about 6 hours of care a day for each person with dementia living at home. That is the work of more than 40 million full-time workers, a figure projected to reach 65 million by 2030.32Alzheimer’s Disease International. Global estimates of informal care In lower-middle-income countries, unpaid care makes up about 85% of the total cost.33PubMed. The global macroeconomic burden of Alzheimer’s disease and other dementias: estimates and projections for 152 countries or territories In the United States, the cost of paid care alone is projected to rise from $196 billion in 2020 to $1.4 trillion by 2060.34PubMed Central. Cost of care for Alzheimer’s disease and related dementias in the United States: 2016 to 2060 Ask about respite care and local support groups, and plan for costs early, including insurance and benefits.
Alzheimer’s as a Cause of Death
U.S. deaths from Alzheimer’s more than doubled between 2000 and 2024, while deaths from heart disease fell.35Alzheimer’s Association. Alzheimer’s Disease Facts and Figures From 2007 to 2016, the U.S. death rate from stroke fell by about 22%.36PubMed. Mortality trends of stroke and dementia: Changing landscapes and new challenges Over the same period, death rates rose by about 1.2 times for Alzheimer’s, 2 times for vascular dementia and 3 times for Lewy body dementia.37PubMed. Mortality trends of stroke and dementia: Changing landscapes and new challenges Among people with dementia in the United States, about 231,000 more died than expected from mid-2020 to 2022, mostly from COVID-19.38PubMed Central. Medical visits and mortality among dementia patients during the COVID-19 pandemic compared to rates predicted from 2019
Heart disease and stroke deaths have fallen partly because of better blood pressure control, cholesterol drugs and emergency treatment, and those advances let more people survive to ages when dementia is common. No treatment so far stops or reverses Alzheimer’s, so there has been no equivalent improvement to push its death numbers down.
Dementia appears on the death certificates of only about a quarter of people who had it.39PubMed. Reporting of dementia on death certificates: a community study So the true number of deaths linked to dementia is likely higher than official figures show.
Death usually comes in the late stages. Common direct causes are pneumonia, infections and trouble swallowing, and certificates often list the infection rather than the dementia. Planning for late-stage care and comfort helps families prepare.
New Treatments and Who Can Get Them
Newer drugs that clear amyloid, a protein that builds up in the brain in Alzheimer’s, are meant for early-stage disease. At one specialist memory clinic, only about 21% of people diagnosed with mild memory problems or Alzheimer’s qualified.40PubMed Central. “Real‐world” eligibility for anti‐amyloid treatment in a tertiary memory clinic setting Many people were left out because their disease had moved past the early stage the drugs were studied in, or because other health conditions made treatment risky.
Testing is the bottleneck. Some blood tests now agree with brain scans about 80 to 90% of the time in detecting Alzheimer’s brain changes.41PubMed Central. Interchangeability of blood‐based biomarkers and PET to identify Alzheimer’s disease pathology Still, shortages of scans and specialists can delay access to these treatments.42Canadian Journal of Health Technologies. Health System Readiness for Disease-Modifying Therapies for Alzheimer Disease
If you are asking a doctor about these drugs, ask whether the stage of the disease is early enough, and expect tests to confirm amyloid in the brain. Ask about side effects and the need for regular monitoring scans, and whether trial results apply to people like you. Being ineligible does not mean being without options, since a diagnosis still opens up other support, symptom treatments and planning.