Alzheimer's Disease and Dementia Life Expectancy

Researchers in 2016 estimated that there were 43.8 million people in the world with Alzheimer's disease or other forms of dementia—27 million women and 16.8 million men. These numbers are growing rapidly. In fact, it's expected to more than double to 100 million by 2050. Here's what you should know about Alzheimer's disease and dementia life expectancy.

Senior mother and daughter hugging
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In 2019, researchers estimated that 5.8 million Americans were living with Alzheimer's dementia. This included about 5.6 million people over the age of 65 and about 200,000 people with early-onset disease. One in ten people 65 and older has Alzheimer's disease, and about 32% of Americans over the age of 85 has the disease. Eighty-one percent of people with Alzheimer's are 75 years old or older.

Read more about how perseveration is a common symptom of Alzheimer's disease.

Life Expectancy

Figuring out the impact of Alzheimer’s disease on life expectancy and longevity is complicated, as people are normally older when they are diagnosed with the disease, and they may have multiple conditions impacting their life expectancy. However, here's what we do know about Alzheimer's disease and life expectancy.

According to researchers, life expectancy for those 65 and older with Alzheimer's disease varies between four to eight years after diagnosis but some live as long as 20 years. The main predictor is age, as those diagnosed at a younger age tend to live longer.

Alzheimer's disease is the sixth leading cause of death in the United States with 121,404 deaths attributed to it in 2017. According to the Alzheimer's Foundation of America, the disease usually progresses over anywhere from two to 20 years.

In one study, researchers at the Johns Hopkins Bloomberg School of Public Health found that having late-stage Alzheimer's disease increases the risk of death by 8% each year. This 8% increase in risk remains constant with aging and is added to other risk factors, such as heart disease.

Factors That Determine Longevity

One study of 438 patients in the U.K. found that the main factors that determine how long a person lives after being diagnosed with Alzheimer's disease (or another form of dementia) are age, gender, and level of disability. Here are the main research findings:

  • Women lived an average of 4.6 years after diagnosis, and men lived 4.1 years.
  • People diagnosed when under age 70 lived 10.7 years compared to 3.8 years for people over 90 when diagnosed.
  • Patients who were frail at the time of diagnosis did not live as long, even after adjusting for age.
  • Overall, the average survival time for someone in the study diagnosed with Alzheimer's disease or dementia was 4.5 years.

Improving Quality of Life

In the early stages of Alzheimer's disease, cognitive impairment is not the only determinant of quality of life. While you can't change factors such as age at diagnosis or gender, research shows that the care that a person receives impacts life expectancy. Be sure that you explore options when it comes to creating a care plan for a loved one diagnosed with Alzheimer's disease and take advantage of any support groups or other resources that may help.

Recent research indicates that factors associated with a lower quality of life for Alzheimer's disease patients include patient depression and anxiety, and having to take multiple medicines—indicative of having other disease states to manage. Efforts to improve the quality of life for patients should include an assessment of these factors so they can be effectively addressed. Caregiver quality of life should also be assessed, especially as the disease progresses and the burden of caregiving increases.

The extent to which a person with the disease can maintain his or her social relationships can also play a large role. Patients should talk with their doctor or a psychologist for strategies to cope with social situations.

In addition, maintaining household responsibilities for as long as able can help improve the quality of life. In later stages, a patient's needs may change, and it is important for a caregiver to know how to care for themselves in addition to their loved one.


Compelling research indicates that targeting treatable disease states associated with the development of Alzheimer's disease, as well as modifiable lifestyle factors, may be an approach to preventing the disease. The treatable disease states include vascular diseases like high blood pressure and stroke, along with other diseases like diabetes and depression. Modifiable lifestyle factors that people can address are level of physical activity or exercise, sleep habits, diet, not smoking, and not being a heavy drinker.

There have been many studies looking into the use of puzzles and other forms of “mental fitness” to help delay or prevent Alzheimer’s disease and dementia. A famous study of nuns showed that the individuals most curious and engaged mentally in the world had a lower risk of developing Alzheimer’s disease and dementia.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. GBD 2016 Dementia Collaborators. Global, regional, and national burden of Alzheimer's disease and other dementias, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol. 2019;18(1):88-106. doi.10.1016/S1474-4422(18)30403-4

  2. Alzheimer’s Association. 2019 Alzheimer’s disease facts and figures. Alzheimers Dement 2019;15(3):321-87.

  3. Heron M. Deaths: Leading causes for 2017. National Vital Statistics Reports; vol 68 no 6. Hyattsville, MD: National Center for Health Statistics. 2019.

  4. Barbe C, Jolly D, Morrone I, et al. Factors associated with quality of life in patients with Alzheimer's disease. BMC Geriatr. 2018;18(1):159. doi.10.1186/s12877-018-0855-7

  5. Edwards iii G, Gamez N, Escobedo G, Calderon O, Moreno-Gonzalez I. Modifiable risk factors for Alzheimer's disease. Front Aging Neurosci. 2019;11:146. doi.10.3389/fnagi.2019.00146

Additional Reading

By Mark Stibich, PhD
Mark Stibich, PhD, FIDSA, is a behavior change expert with experience helping individuals make lasting lifestyle improvements.