# What is Alzheimer life expectancy?

Looks up the median survival after dementia begins, by age at onset and sex, from a large population study in England and Wales (Xie 2008), with the range in which the middle half of people lived.

- Page: https://www.acalculator.org/health/alzheimers-life-expectancy-calculator
- JSON spec: https://www.acalculator.org/health/alzheimers-life-expectancy-calculator.json
- Version: 5208e9014420

## Default answer

Example with the default inputs (Age when dementia began 75, Sex Both): For women and men, onset at 70 to 79, the median survival in the study was 5.4 years; the middle half lived 3.4 to 8.3 years.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| age | Age when dementia began | Age in whole years when the dementia began, 65 to 110. The study had no one younger than 65. |
| sex | Sex | Women, men, or both together, as the study reported them. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| median | Median survival | Half of the people in this group lived longer than this after onset (Xie 2008, Table 2). |
| range | Middle half lived | The interquartile range: a quarter died sooner, a quarter lived longer. |
| group | Study group | The age group and sex the row comes from. |

## Method

A table lookup, with no model: the row of Xie 2008, Table 2 for the age group at onset (65 to 69, 70 to 79, 80 to 89, 90 or more) and sex (women, men, or all).

## Assumptions

- From 438 people over 65 who developed dementia in the MRC Cognitive Function and Ageing Study, England and Wales, 1991 to 2005.
- Onset is the midpoint between the last follow-up without dementia and the first with it. The study counts all dementia, not only Alzheimer’s disease.
- A median describes a group. It does not predict how long one person will live.

## Worked examples

1. age = 75, sex = any gives median = 5.4 years, range = 3.4 to 8.3 years, group = women and men, onset at 70 to 79. Source: Xie 2008, Table 2: onset at 70 to 79, all, median 5.4 (IQR 3.4 to 8.3).
2. age = 85, sex = female gives median = 4.4 years, range = 2.8 to 7.0 years. Source: Xie 2008, Table 2: onset at 80 to 89, women, median 4.4 (IQR 2.8 to 7.0).
3. age = 92, sex = male gives median = 3.4 years, range = 1.5 to 5.5 years. Source: Xie 2008, Table 2: onset at 90 or more, men, median 3.4 (IQR 1.5 to 5.5).
4. age = 67, sex = male gives median = Not reached in the study, range = 9.1 years or more (upper quartile not reached). Source: Xie 2008, Table 2: onset at 65 to 69, men, median NA (lower quartile 9.1, upper NA).
5. age = 69, sex = female gives median = 7.5 years, range = 4.8 years or more (upper quartile not reached), group = women, onset at 65 to 69. Source: Xie 2008, Table 2: onset at 65 to 69, women, median 7.5 (IQR 4.8 to NA).

## FAQ

### What is the life expectancy after an Alzheimer's diagnosis?

It depends most on age. In the study this page uses (Xie 2008), half of the people whose dementia began at 70 to 79 lived 5.4 years or more, and half of those whose dementia began at 90 or later lived 3.8 years or more. Brookmeyer (2002) found a median of 8.3 years for Alzheimer’s disease diagnosed at 65 and 3.4 years at 90.

### Do women live longer with dementia than men?

In Xie 2008 the median was 4.6 years for women and 4.1 years for men overall. Larson (2004) found 5.7 years for women and 4.2 years for men after a diagnosis of Alzheimer’s disease.

### Why does the page talk about dementia and not only Alzheimer’s?

The study with an open table by age and sex counted all dementia, of which Alzheimer’s disease is the most common type. Studies of Alzheimer’s alone give similar figures, but their tables by age are not open to readers.

### What does "not reached" mean?

For men whose dementia began at 65 to 69, fewer than half had died by the end of the study, so no median could be given. A quarter of them died within 9.1 years.

### What is the "middle half" range?

The interquartile range: a quarter of the group died before its low end and a quarter lived past its high end.

### Can this predict how long one person will live?

No. A median describes a group. Health, how advanced the dementia is, falls, and other illnesses change the outlook for one person a great deal.

## Sources

- Xie J, Brayne C, Matthews FE; Medical Research Council Cognitive Function and Ageing Study collaborators. Survival times in people with dementia: analysis from population based cohort study with 14 year follow-up. BMJ. 2008;336(7638):258-262. https://doi.org/10.1136/bmj.39433.616678.25 (Table 2, open at https://pmc.ncbi.nlm.nih.gov/articles/PMC2223023/, retrieved 2026-10-05)
- Brookmeyer R, Corrada MM, Curriero FC, Kawas C. Survival following a diagnosis of Alzheimer disease. Arch Neurol. 2002;59(11):1764-1767. https://doi.org/10.1001/archneur.59.11.1764 (abstract, retrieved 2026-10-05)
- Larson EB, Shadlen MF, Wang L, et al. Survival after initial diagnosis of Alzheimer disease. Ann Intern Med. 2004;140(7):501-509. https://doi.org/10.7326/0003-4819-140-7-200404060-00008 (abstract, retrieved 2026-10-05)