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Cited by 195Down syndrome and intellectual disability researchDementia and Cognitive Impairment ResearchAlzheimer's disease research and treatments

Association of Alzheimer Disease With Life Expectancy in People With Down Syndrome

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Iulita, Maria Florencia, Garzón Chavez, Diana, Klitgaard Christensen, Maria, Valle Tamayo, Natalia, Plana-Ripoll, Oleguer, Rasmussen, Sonja A., Roqué Figuls, Marta, Alcolea, Daniel +13 more·2022·JAMA Network Open
DOI 10.1001/jamanetworkopen.2022.12910PMC PMC9127560
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Abstract

Importance: People with Down syndrome have a high risk of developing Alzheimer disease dementia. However, penetrance and age at onset are considered variable, and the association of this disease with life expectancy remains unclear because of underreporting in death certificates. Objective: To assess whether the variability in symptom onset of Alzheimer disease in Down syndrome is similar to autosomal dominant Alzheimer disease and to assess its association with mortality. Design, Setting, and Participants: This study combines a meta-analysis with the assessment of mortality data from US death certificates (n = 77 347 case records with a International Classification of Diseases code for Down syndrome between 1968 to 2019; 37 900 [49%] female) and from a longitudinal cohort study (n = 889 individuals; 46% female; 3.2 [2.1] years of follow-up) from the Down Alzheimer Barcelona Neuroimaging Initiative (DABNI). Main Outcomes and Measures: A meta-analysis was conducted to investigate the age at onset, age at death, and duration of Alzheimer disease dementia in Down syndrome. PubMed/Medline, Embase, Web of Science, and CINAHL were searched for research reports, and OpenGray was used for gray literature. Studies with data about the age at onset or diagnosis, age at death, and disease duration were included. Pooled estimates with corresponding 95% CIs were calculated using random-effects meta-analysis. The variability in disease onset was compared with that of autosomal dominant Alzheimer disease. Based on these estimates, a hypothetical distribution of age at death was constructed, assuming fully penetrant Alzheimer disease. These results were compared with real-world mortality data. Results: In this meta-analysis, the estimate of age at onset was 53.8 years (95% CI, 53.1-54.5 years; n = 2695); the estimate of age at death, 58.4 years (95% CI, 57.2-59.7 years; n = 324); and the estimate of disease duration, 4.6 years (95% CI, 3.7-5.5 years; n = 226). Coefficients of variation and 95% prediction intervals of age at onset were comparable with those reported in autosomal dominant Alzheimer disease. US mortality data revealed an increase in life expectancy in Down syndrome (median [IQR], 1 [0.3-16] years in 1968 to 57 [49-61] years in 2019), but with clear ceiling effects in the highest percentiles of age at death in the last decades (90th percentile: 1990, age 63 years; 2019, age 65 years). The mortality data matched the limits projected by a distribution assuming fully penetrant Alzheimer disease in up to 80% of deaths (corresponding to the highest percentiles). This contrasts with dementia mentioned in 30% of death certificates but is in agreement with the mortality data in DABNI (78.9%). Important racial disparities persisted in 2019, being more pronounced in the lower percentiles (10th percentile: Black individuals, 1 year; White individuals, 30 years) than in the higher percentiles (90th percentile: Black individuals, 64 years; White individuals, 66 years). Conclusions and Relevance: These findings suggest that the mortality data and the consistent age at onset were compatible with fully penetrant Alzheimer disease. Lifespan in persons with Down syndrome will not increase until disease-modifying treatments for Alzheimer disease are available.

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  • DS is among the select few conditions that encompass both neurodevelopmental and neurodegenerative clinical features, with most individuals demonstrating progressive cognitive impairment by mid-adulthood.

    “DS is among the select few conditions that encompass both neurodevelopmental and neurodegenerative clinical features, with most individuals demonstrating progressive cognitive impairment by mid-adulthood (77, 78).”

    From Molecular and cellular processes disrupted in the early postnatal Down syndrome prefrontal cortex (2026) · cites this paper as [78]

    The Introduction (page unavailable) identifies Down syndrome as a genetic cause of intellectual disability and reports Alzheimer-related neuropathology by age 40, supporting the developmental and degenerative aspects. The Results (page unavailable) give a pooled mean age of 53.8 years for dementia onset, but do not establish that most individuals have progressive cognitive impairment by mid-adulthood; pathology by 40 is not the same as clinical impairment. (LLM, conf=0.85)

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  • By age 55 years, more than half of people with DS will have developed clinical dementia caused by AD, and by age 70 years, virtually all individuals with DS will have AD-dementia.

    “By the age of 55 years, more than half of people with DS will have developed clinical dementia, caused by AD, and by age 70 years, virtually all individuals with DS will have AD-dementia [28, 33, 41, 47].”

    From Apolipoprotein E abundance is elevated in the brains of individuals with Down syndrome–Alzheimer’s disease (2025) · cites this paper as [33]

    The Results (Systematic Review and Meta-analysis; page unavailable) give a pooled mean age of 53.8 years for onset of Alzheimer dementia in people with Down syndrome, but do not establish that more than half have developed it by age 55. The Introduction reports an Alzheimer disease risk above 90% by the seventh decade, and the Discussion suggests near-full penetrance; neither establishes that virtually all have clinical AD dementia by age 70. (LLM, conf=0.83)

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  • DS-AD is likely the single greatest impediment to extending life expectancy of adults with Down syndrome beyond their 60s.

    “DS‐AD is likely the single greatest impediment to extending life expectancy of adults with DS beyond their 60s. 7”

    From The Alzheimer's Biomarker Consortium–Down Syndrome (ABC‐DS): A 10‐year report (2025) · cites this paper as [7]

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7 of the 93 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. [23]Egger M, Smith GD, Altman DG, eds. Systematic Reviews in Health Care: Meta-analysis in Context. Wiley; 2001.

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Authors
Iulita, M. F., Garzón Chavez, D., Klitgaard Christensen, M., Valle Tamayo, N., Plana-Ripoll, O., Rasmussen, S. A., Roqué Figuls, M., Alcolea, D., Videla, L., Barroeta, I., Benejam, B., Altuna, M., Padilla, C., Pegueroles, J., Fernandez, S., Belbin, O., Carmona-Iragui, M., Blesa, R., Lleó, A., Bejanin, A., & Fortea, J.
Affiliations
  • Universitat Autònoma de Barcelona (ES)
  • Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
  • National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
  • University of Florida Health (US)
  • Iberoamerican Cochrane Centre, Biomedical Research Institute Sant Pau, Barcelona, Spain
  • Barcelona Down Medical Center, Fundació Catalana Síndrome de Down, Barcelona, Spain
Corresponding author
  • Iulita, Maria Florencia
  • Fortea, Juan
ORCID
Venue
JAMA Network Open
Publisher
American Medical Association (AMA)
Published
2022-05-23
Volume
5
Issue
5
Pages
e2212910
ISSN
2574-3805 (ISSN-L)
DOI
10.1001/jamanetworkopen.2022.12910
PMC
PMC9127560
OpenAlex
W4281388023
Cited by
195
References
93
Citations by year
2026: 36 · 2025: 71 · 2024: 50 · 2023: 28 · 2022: 10
FWCI
7.90
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • JAMA Network Open (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Dipòsit Digital de Documents de la UAB (Universitat Autònoma de Barcelona) (submittedVersion, cc-by)
  • Scopus (Elsevier) (submittedVersion, other-oa)
Funders
  • European Commission (837180)
  • Lundbeckfonden (R345-2020-1588)
  • National Institute on Aging (R01AG013566, R01AG056480, R21AG056974)
Topics
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Down syndrome and intellectual disability research
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
Keywords
Down syndrome, Alzheimer's disease, dementia, life expectancy, age of onset, age at death, disease duration, mortality, autosomal dominant Alzheimer's disease, penetrance
MeSH terms
Aged, Alzheimer Disease, Down Syndrome, Female, Humans, Life Expectancy, Longitudinal Studies, Male, Middle Aged, Cohort Studies

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