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Trends in the prevalence and mortality of cognitive impairment in the United States: is there evidence of a compression of cognitive morbidity?
Langa KM, Larson EB, Karlawish JH, Cutler DM, Kabeto MU, Kim SY, Rosen AB.. Alzheimer's & dementia : the journal of the Alzheimer's Association, 2008-03-04
Topic: Risk, prevention and care in population studies
Background Recent medical, demographic, and social trends might have had an important impact on the cognitive health of older adults. To assess the impact of these multiple trends, we compared the prevalence and 2-year mortality of cognitive impairment (CI) consistent with dementia in the United States in 1993 to 1995 and 2002 to 2004. Methods We used data from the Health and Retirement Study (HRS), a nationally representative population-based longitudinal survey of U.S. adults. Individuals aged 70 years or older from the 1993 (N = 7,406) and 2002 (N = 7,104) waves of the HRS were included. CI was determined by using a 35-point cognitive scale for self-respondents and assessments of memory and judgment for respondents represented by a proxy. Mortality was ascertained with HRS data verified by the National Death Index. Results In 1993, 12.2% of those aged 70 or older had CI compared with 8.7% in 2002 (P Conclusions These findings support the hypothesis of a compression of cognitive morbidity between 1993 and 2004, with fewer older Americans reaching a threshold of significant CI and a more rapid decline to death among those who did. Societal investment in building and maintaining cognitive reserve through formal education in childhood and continued cognitive stimulation during work and leisure in adulthood might help limit the burden of dementia among the growing number of older adults worldwide.
Key findings
- Results In 1993, 12.2% of those aged 70 or older had CI compared with 8.7% in 2002 (P < .001).
Why it matters
In a nationally representative US survey (Health and Retirement Study), 12.2% of people aged 70 or older had cognitive impairment consistent with dementia in 1993, compared with 8.7% in 2002. The authors read this as a "compression of cognitive morbidity": fewer older Americans reached significant impairment, and those who did declined to death more rapidly. They propose, but did not test, that education and lifelong cognitive stimulation might help limit the burden of dementia.
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Study details
- Study designlongitudinal study
- Participants7,406
- Effect size12.2%; 8.7%
- Evidence strengthModerate
How this study scored 67/100
Published in a leading specialty journal, and it is a longitudinal study following the same people over time. Scored zero for randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Alzheimer's & dementia : the journal of the Alzheimer's Association) |
| Journal's citation record | 2 / 4 | Alzheimer s & Dementia: journal h-index 228 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2008 — within 20 year(s) of the newest study here |
| Sample size | 3 / 4 | 7,406 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 6 / 7 | Cited 381 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 19.1 citations a year over 20 year(s) since 2008 |
| Impact for its field and year | 4 / 6 | Cited 9.8× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 23 other studies in this library |
| Still being cited | 2 / 4 | Cited 32 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Allison B. Rosen: h-index 36 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Harvard University: institution h-index 3,235 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 7 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 18631957) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 67 / 100 | — |
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Read the original
- DOI: 10.1016/j.jalz.2008.01.001
- PubMed: 18631957
- Original source →
- Free full text: Alzheimer s & Dementia →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record names 7 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
APA 7th
Langa, K. M., Larson, E. B., Karlawish, J. H., Cutler, D. M., Kabeto, M. U., Kim, S. Y., et al. (2008). Trends in the prevalence and mortality of cognitive impairment in the United States: is there evidence of a compression of cognitive morbidity? Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1016/j.jalz.2008.01.001
Vancouver
Langa KM, Larson EB, Karlawish JH, Cutler DM, Kabeto MU, Kim SY, et al. Trends in the prevalence and mortality of cognitive impairment in the United States: is there evidence of a compression of cognitive morbidity? Alzheimer's & dementia : the journal of the Alzheimer's Association. 2008. doi:10.1016/j.jalz.2008.01.001. PMID: 18631957.
BibTeX
@article{langa2008-18631957,
author = {Langa, K. M. and Larson, E. B. and Karlawish, J. H. and Cutler, D. M. and Kabeto, M. U. and Kim, S. Y. and Rosen, A. B.},
title = {{Trends in the prevalence and mortality of cognitive impairment in the United States: is there evidence of a compression of cognitive morbidity?}},
journal = {Alzheimer's \& dementia : the journal of the Alzheimer's Association},
year = {2008},
doi = {10.1016/j.jalz.2008.01.001},
pmid = {18631957},
url = {https://doi.org/10.1016/j.jalz.2008.01.001}
}
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