Aging-Related Disease
Roughly 55 million people live with dementia worldwide; the figure is projected to reach 139 million by 2050 as populations age. Alzheimer's accounts for 60–70% of dementia cases. Parkinson's disease affects ~10 million people globally and is the fastest-growing neurological condition. Combined, neurodegenerative diseases will be the dominant burden of the demographic transition in advanced economies.
Key insights
Dementia is the leading aging-related condition
Alzheimer's disease causes 60–70% of dementia cases. Other major causes: vascular dementia (cerebrovascular damage), Lewy body dementia, frontotemporal dementia. Prevalence rises sharply with age — 5% at 65, 10% at 75, 30% at 85, 50% at 95. As life expectancy rises, exposure to high-prevalence age bands increases, multiplying total cases regardless of underlying biology.
First disease-modifying treatments are now FDA-approved
Aducanumab (2021), lecanemab (2023) and donanemab (2024) are the first FDA-approved Alzheimer's drugs to slow disease progression (rather than just treating symptoms). Effects are modest — ~30% slowing of cognitive decline over 18 months — and access remains limited by cost, infusion requirements, and ARIA (amyloid-related imaging abnormalities) side-effects. The pipeline behind these is the largest in decades.
Asian aging will drive future case loads
Japan currently has the highest dementia prevalence (~12% of those over 65) due to its aging population. China is projected to have the largest absolute case load by 2050 (~28 million cases). Combined Asian dementia cases will exceed those of Europe and North America combined by 2040. Healthcare and long-term care infrastructure in many Asian countries is significantly less prepared for this than in Western Europe or North America.
Projected dementia cases 2024–2050
Millions of people, by region
Key Finding: Total cases roughly triple by 2050; Asia and Africa show the largest absolute growth.
Dementia prevalence — selected countries (2024)
% of population 60+ living with dementia
Key Finding: Japan and Italy lead due to old populations; African countries have lower prevalence partly due to lower life expectancy.
Methodology & caveats
Diagnosis underestimates true prevalence
Many people with dementia are undiagnosed — estimates range from 40% (high-income countries) to 80% (low-income countries) of cases. Diagnosis requires cognitive testing, brain imaging, and clinical assessment that are not always accessible. Prevalence statistics partly reflect diagnostic capacity; comparisons across countries should account for this.
Prevention is starting to be possible
Lancet Commission 2024 reviewed evidence that 45% of dementia cases could be prevented or delayed by addressing 14 modifiable risk factors — less education, hearing loss, depression, head injury, hypertension, obesity, smoking, physical inactivity, diabetes, excessive alcohol, social isolation, air pollution, untreated vision loss, high cholesterol. The window for prevention is mostly midlife (40-65).
Cost calculation
Direct costs (medical care, long-term care) and indirect costs (unpaid family caregiving, lost productivity) for dementia globally are estimated at $1.3T per year. Two-thirds of total costs are informal caregiving — primarily unpaid family labor, mostly female. Aging societies face simultaneous shrinking of working-age population and rising demand for caregiver labor — the policy crunch is structural.