{
  "id": "alzheimers-life-expectancy",
  "version": "5208e9014420",
  "status": "published",
  "name": "Alzheimer's Life Expectancy Calculator",
  "question": "What is Alzheimer life expectancy?",
  "summary": "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.",
  "category": "health",
  "subcategory": "clinical",
  "url": "https://www.acalculator.org/health/alzheimers-life-expectancy-calculator",
  "markdown": "https://www.acalculator.org/health/alzheimers-life-expectancy-calculator.md",
  "kind": "function",
  "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."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "age": {
        "title": "Age when dementia began",
        "description": "Age in whole years when the dementia began, 65 to 110. The study had no one younger than 65.",
        "type": "integer",
        "minimum": 65,
        "maximum": 110
      },
      "sex": {
        "title": "Sex",
        "description": "Women, men, or both together, as the study reported them.",
        "type": "string",
        "enum": [
          "female",
          "male",
          "any"
        ]
      }
    }
  },
  "outputs": {
    "median": {
      "label": "Median survival",
      "description": "Half of the people in this group lived longer than this after onset (Xie 2008, Table 2).",
      "format": "text"
    },
    "range": {
      "label": "Middle half lived",
      "description": "The interquartile range: a quarter died sooner, a quarter lived longer.",
      "format": "text"
    },
    "group": {
      "label": "Study group",
      "description": "The age group and sex the row comes from.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "age": 75,
      "sex": "any"
    },
    "outputs": {
      "median": "5.4 years",
      "range": "3.4 to 8.3 years",
      "group": "women and men, onset at 70 to 79"
    },
    "text": "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."
  },
  "examples": [
    {
      "given": {
        "age": 75,
        "sex": "any"
      },
      "expect": {
        "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)"
    },
    {
      "given": {
        "age": 85,
        "sex": "female"
      },
      "expect": {
        "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)"
    },
    {
      "given": {
        "age": 92,
        "sex": "male"
      },
      "expect": {
        "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)"
    },
    {
      "given": {
        "age": 67,
        "sex": "male"
      },
      "expect": {
        "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)"
    },
    {
      "given": {
        "age": 69,
        "sex": "female"
      },
      "expect": {
        "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)"
    }
  ],
  "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)"
  ],
  "related": [],
  "changelog": [
    {
      "date": "2026-10-05",
      "note": "Published after this site's editorial review against the cited sources (no clinician review); the page notices say so."
    }
  ]
}