Alzheimer’s disease is a progressive neurodegenerative disorder that slowly destroys memory and thinking skills, eventually leading to the inability to carry out simple tasks. It is the most common cause of dementia, a general term for various brain disorders that affect memory, thinking, behavior, and emotion. This article provides an overview of Alzheimer’s disease’s global statistical impact, highlighting its prevalence, distribution, and overall burden.
Current Global Prevalence and Incidence
Worldwide, an estimated 55 million people were living with dementia in 2020, with Alzheimer’s disease being the most common form, contributing to 60-70% of these cases. The World Health Organization (WHO) reported 57 million people had dementia globally in 2021, with approximately 10 million new cases arising each year, or one every 3 seconds.
Despite these high numbers, a significant portion of individuals with dementia remain undiagnosed. Studies suggest that only 20-50% of cases are recognized and documented in primary care within high-income countries. This “treatment gap” is considerably larger in low and middle-income countries, where estimates indicate up to 90% remain undiagnosed. This means most people with dementia worldwide have not received a formal diagnosis, limiting their access to treatment and support.
Demographic and Geographic Distribution
The prevalence and incidence of Alzheimer’s disease increase significantly with age, though cases before age 65 are also recognized. In the United States, about 1 in 9 people aged 65 and older have Alzheimer’s, with 74% of those affected being 75 or older. Globally, the age-standardized incidence rate of dementia has shown an increasing pattern over recent decades.
Women consistently exhibit higher incidence rates of Alzheimer’s disease across all regions. For instance, nearly two-thirds of Americans with Alzheimer’s are women, and the lifetime risk for Alzheimer’s at age 45 is 1 in 5 for women compared to 1 in 10 for men.
Geographic variations also exist, with 60% of people with dementia already residing in low and middle-income countries. This proportion is projected to rise to 71% by 2050. The fastest growth in the elderly population, and consequently in dementia cases, is occurring in countries like China, India, and their South Asian and Western Pacific neighbors. High-income countries, however, account for a larger share of direct health care spending related to dementia, despite having a smaller proportion of the total prevalence.
Economic and Societal Burden
Alzheimer’s disease imposes a substantial financial burden, making it one of the costliest global conditions. In 2019, dementia cost economies worldwide an estimated US$1.3 trillion. Approximately 50% of these costs are from informal caregivers, such as family members and close friends.
Healthcare and long-term care costs are significant components of this economic burden. In the United States, health and long-term care costs for people with Alzheimer’s and other dementias are projected to reach $384 billion in 2025, excluding the value of unpaid caregiving. These total payments are expected to increase to nearly $1 trillion by 2050.
Beyond economic figures, the societal impact of Alzheimer’s disease is profound, particularly on caregivers. Globally, women provide 70% of care hours for people living with dementia. In the United States, nearly 12 million Americans provide unpaid care for individuals with Alzheimer’s or other dementias, contributing an estimated 19 billion hours in 2024, valued at over $413 billion.
Projections for the Future
Projections indicate a significant increase in global Alzheimer’s disease prevalence and incidence in coming decades, primarily due to aging populations. The number of people living with dementia is expected to almost double every 20 years, reaching 78 million in 2030 and potentially 139 to 153 million by 2050.
Much of this projected increase will occur in developing countries, with low and middle-income nations bearing a growing proportion of the global burden. For example, the greatest increase in dementia prevalence is expected in Sub-Saharan Africa and North Africa, with projected increases of 357% and 367% respectively. While improvements in education globally could potentially reduce dementia prevalence, these benefits may be offset by anticipated increases in risk factors such as obesity, smoking, and high blood sugar. These rising numbers underscore the growing global health challenge posed by Alzheimer’s disease.