The average life expectancy for a person with Alzheimer’s disease is 5.8 years after diagnosis. However, early diagnosis can give people and their loved ones the chance to put in place lifestyle changes that can delay or prevent the onset of Alzheimer’s dementia.

Alzheimer’s disease (AD) is a degenerative brain disorder. The disease breaks down and destroys brain cells and the neurons that connect brain cells to one another. This damage causes a decline in memory, behavior, and mental capabilities.

Every person’s journey with AD is different. For some, the disease progresses slowly and leaves mental function largely intact for several years. Other times, AD is aggressive and quickly robs people of their memory. In the end, AD becomes severe enough to disrupt day-to-day life. In later stages, people will need almost constant care.

AD is currently the most common cause of dementia in the United States. According to the Centers for Disease Control and Prevention (CDC), 5.8 million people in the United States have AD. Researchers and scientists have been studying the disease for decades, but there’s currently no cure.

Quality of life becomes increasingly important for people with AD and their caretakers once a diagnosis is made.

Life expectancy varies for each person with AD. According to a 2021 systematic review of studies, the average life expectancy for someone with AD is 5.8 years after diagnosis.

It can take a long time to get an AD diagnosis. Those who have trouble thinking or remembering may undergo several types of tests, such as blood and urine analysis, brain imaging scans, and psychiatric evaluations. The National Institutes of Health (NIH) recommends that someone with memory problems see a doctor every 6 to 12 months.

Early diagnosis can give a person the chance to reduce risk factors, which can delay the onset of later stages of AD.

A 2022 study involving 2,449 people over age 65 found that a healthy lifestyle, including a nutritious diet, exercise, and light or no alcohol use, can decrease the number of years a person lives with Alzheimer’s dementia.

In the study, women who lived with 4 or 5 healthy lifestyle factors spent an average of 2.6 years with dementia, while those with 0 or 1 healthy factor spent an average of 4.1 years with dementia.

In men, the average was 1.4 years with dementia with 4 or 5 healthy lifestyle factors, and 2.1 years with 0 or 1 healthy lifestyle factor.

Ultimately, AD will progress and take its toll on the brain and body. As it progresses, symptoms and side effects will get worse.

However, a few medications may be able to slow the progression of AD at least for a short time. Treatment can also improve your quality of life and help treat symptoms. Talk with your doctor about your treatment options.

According to a 2020 Lancet Commission study on dementia prevention, modifying 12 risk factors may delay or prevent up to 40% of dementia diagnoses worldwide. Those risk factors are:

  • reducing alcohol consumption
  • avoiding head injury
  • avoiding air pollution
  • focusing on education
  • lowering high blood pressure
  • improving hearing
  • stopping smoking
  • treating obesity
  • managing depression
  • treating diabetes
  • being physically active
  • focusing on social engagement

While increasing age is the largest known risk factor for Alzheimer’s, the disease is not a typical part of aging. Most people diagnosed with Alzheimer’s are ages 65 and over. The risk of AD nearly doubles every 5 years after age 65. After age 85, the risk increases to almost one-third.

Early diagnosis gives a person the opportunity to put in place lifestyle changes that can help reduce risk factors for dementia, which can delay or prevent the onset of dementia symptoms.

There are three stages of AD. Most people spend the most time in the middle stage with moderate symptoms. It’s possible for symptoms to overlap between stages, so there is no clear cut-off between stages.

Early stage (mild)

Most people are diagnosed in the early stage. After diagnosis, the average life expectancy is 5.8 years, but it can be 20 years or more.

In the early stage, people experience:

  • memory loss
  • cognitive (thinking) problems
  • difficulties with money and bills
  • getting lost
  • personality changes

Middle stage (moderate)

In this stage, the parts of the brain that control language, sensory processing, reasoning, and conscious thought become damaged. People generally spend most of the years after their AD diagnosis in this middle stage. They may experience:

  • worsening memory loss
  • worsening confusion
  • trouble recognizing friends and family
  • trouble performing tasks like getting dressed
  • trouble learning new things
  • trouble coping with new environments or situations
  • hallucinations
  • delusions
  • paranoia
  • impulsive behavior

Late stage (severe)

In late stage AD, changes to the brain have made tissue much smaller. Plaques and tangles in the brain have spread, so functioning declines significantly. People may experience:

  • complete dependency on others for care
  • loss of communication
  • loss of movement

Each person has a unique health history. Their health history is directly related to how AD will affect them. It’s helpful to know the statistics about average life expectancy, as well as how lifestyle and age can alter that length of time.

If you’re a caretaker or were recently diagnosed with AD, you can find empowerment and courage in knowing how the condition tends to progress. This information is helpful as you, your family, and your caretakers are planning your health support journey.

Here are some questions people often ask about Alzheimer’s and life expectancy:

How does Alzheimer’s lead to death?

In the late stages of Alzheimer’s, people may not be able to move on their own. They may also experience swallowing issues and other eating challenges. The loss of communication may make it hard for them to express their wishes. These and other factors can make people more vulnerable to illness, which can lead to death.

How long can a 70-year-old live with dementia?

People can live for many years with an AD diagnosis. Dementia is a symptom of the later stages of Alzheimer’s disease. In one 2022 study, people lived an average of 1.4 to 4.1 years with dementia, depending on gender and healthy lifestyle factors.

Which stage of Alzheimer’s generally lasts the longest?

The stages of Alzheimer’s vary from person to person. Generally, the middle, or moderate, stage of AD lasts the longest.

How do you know when an Alzheimer’s patient is near the end?

In the late, or severe, stage of Alzheimer’s, a person may rely on others for day-to-day care. They may be completely unable to communicate and spend most of their time in bed. At this stage, the body begins to shut down.

You may want to consider talking with your doctor about how your risk factors and lifestyle may affect your life expectancy. Work with your doctor to find the best treatments and lifestyle changes for your situation.

If you’re a caretaker for a person with AD, work with their doctor to learn about treatments and lifestyle changes that may help slow the disease progression.

Alzheimer’s disease is not curable, but there are measures you can take to help ease its impact on quality of life and day-to-day activities.