Alzheimer's Disease
It starts as a misplaced set of keys and can grow into the slow loss of the story a person tells about their own life.
By Greg Goodwin · Published October 24, 2026
Cheat Sheet
- Scale: an estimated 7.4 million Americans age 65 and older are living with Alzheimer's in 2026, about 1 in 9 people in that age group.
- Age: 74% of those with Alzheimer's are age 75 or older, and almost two-thirds are women.
- Projection: the number of Americans 65 and older with Alzheimer's may reach 13.8 million by 2060 without medical breakthroughs.
- Lifespan: people 65 and older survive an average of four to eight years after diagnosis, though some live as long as 20.
- Mortality: it was officially the fifth-leading cause of death among people 65 and older in 2024.
- Caregiving: nearly 13 million Americans provide unpaid care for someone with dementia, and 2026 costs are projected at $409 billion.
The 60-Second Version
Alzheimer's disease is a progressive brain disorder and the most common cause of dementia, the broad term for memory and thinking problems serious enough to disrupt daily life. Over years, abnormal protein deposits and loss of nerve cells damage the brain, beginning with memory and eventually affecting language, judgment, and basic functions. It is not a normal part of aging, though age is the biggest risk factor: the Alzheimer's Association estimates 7.4 million Americans age 65 and older are living with it in 2026. Symptoms and speed of change vary from person to person. Families often bear much of the care, which is one reason the disease is described as affecting whole households, not only patients. This page is general education, not medical advice; anyone worried about memory changes should see a clinician.
The Long Version
What Is Happening in the Brain
Alzheimer's is characterized by two protein abnormalities that researchers have studied for decades: amyloid plaques, which accumulate between nerve cells, and tau tangles, which form inside them. Along with these changes, nerve cells lose their connections and die, and the brain shrinks. Early damage tends to affect regions involved in forming new memories, which is why trouble remembering recent conversations is a common early sign. As the disease spreads, it affects other regions responsible for language, reasoning, and movement. Researchers are still working out exactly how plaques, tangles, inflammation, and other factors interact, so the full cause remains an active area of study.
How Common It Is
The Alzheimer's Association's 2026 Facts and Figures report estimates 7.4 million Americans age 65 and older are living with Alzheimer's, about 1 in 9 people in that age group. Seventy-four percent are age 75 or older, and almost two-thirds are women. Researchers believe about 110 of every 100,000 people age 30 to 64, roughly 200,000 Americans, have younger-onset dementia. Looking ahead, the report says the number of people 65 and older with Alzheimer's may reach a projected 13.8 million by 2060, barring medical breakthroughs. A large driver is simple demographics: all members of the baby boom generation will be 65 or older by 2030.
Course and Outlook
Alzheimer's progresses gradually, usually described in stages from early to severe, but individuals move through them at different speeds. The Alzheimer's Association reports that people 65 and older survive an average of four to eight years after a diagnosis, yet some live as long as 20 years. It also notes that a person who lives from age 70 to 80 with Alzheimer's dementia will spend an average of 40% of that time in the severe stage. Alzheimer's was officially listed as the fifth-leading cause of death among people 65 and older in 2024, and deaths from it more than doubled between 2000 and 2024, even as deaths from heart disease fell.
Who Is Affected Most
Risk is not shared evenly. The Alzheimer's Association reports that older Black Americans are about twice as likely to have Alzheimer's or other dementias as older White Americans, and older Hispanic Americans about one and one-half times as likely. Lifetime risk at age 45 is estimated at 1 in 5 for women and 1 in 10 for men. The causes of these differences are complex and may involve health conditions, access to care, and social factors. For individuals, family history and age matter, and a clinician can discuss personal risk, memory concerns, and what evaluation involves.
The Caregiving Reality
Much of the burden falls on families. Nearly 13 million Americans provide unpaid care for a family member or friend with dementia, valued at $446.3 billion, and the association reports that 59% of dementia caregivers feel high to very high emotional stress. Health and long-term care costs for people living with dementia are projected to reach $409 billion in 2026, not counting unpaid caregiving. Support exists: the Alzheimer's Association runs a free 24/7 helpline, 800.272.3900, for information and emotional support, and clinicians can point families toward local resources.
Why People Care
Alzheimer's affects millions of people and, through caregiving, millions more. Knowing that it is a disease rather than normal aging helps families notice changes sooner and seek evaluation, and helps friends respond with patience. This is general information, not medical advice; talk with a clinician about any memory concerns.
Glossary
- Dementia
- An umbrella term for loss of thinking, memory, and reasoning serious enough to interfere with daily life; Alzheimer's is the most common cause.
- Amyloid plaques
- Clumps of a protein fragment that build up between nerve cells and are a hallmark of Alzheimer's.
- Tau tangles
- Twisted fibers of the protein tau inside nerve cells, another hallmark of the disease.
- Mild cognitive impairment
- Thinking or memory changes that are noticeable but do not yet disrupt everyday independence.
- Younger-onset
- Alzheimer's or another dementia that begins before age 65.
Go Deeper
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