Conversion to dementia from mild cognitive disorder: the Cache County Study
Tschanz JT, Welsh-Bohmer KA, Lyketsos CG, Corcoran C, Green RC, Hayden K, Norton MC, Zandi PP et al.. Neurology, 2006-07-01
Topic: Risk, prevention and care in population studies
Objective To examine 3-year rates of conversion to dementia, and risk factors for such conversion, in a population-based sample with diverse types of cognitive impairment. Methods All elderly (aged 65 or older) residents of Cache County, UT, were invited to undergo two waves of dementia screening and assessment. Three-year follow-up data were available for 120 participants who had some form of mild cognitive impairment at baseline. Of these, 51 had been classified at baseline with prodromal Alzheimer disease (proAD), and 69 with other cognitive syndromes (CS). Results Three-year rates of conversion to dementia were 46% among those with cognitive impairment at baseline. By comparison, 3.3% without impairment converted to dementia in the interval. Among converters, AD was the most common type of dementia. In individuals with at least one APOE epsilon4 allele, those with proAD or CS exhibited a 22- to 25-fold higher risk of dementia than cognitively unimpaired individuals (vs 5- to 10-fold higher risk in those without epsilon4). Conclusions Individuals with all types of mild cognitive impairment have an elevated risk of dementia over 3 years, more so in those with an APOE epsilon4 allele. These results suggest value in dementia surveillance for broad groups of cognitively impaired individuals beyond any specific category, and utility of APOE genotyping as a prognostic method.
Key findings
- Results Three-year rates of conversion to dementia were 46% among those with cognitive impairment at baseline.
- In individuals with at least one APOE epsilon4 allele, those with proAD or CS exhibited a 22- to 25-fold higher risk of dementia than cognitively unimpaired individuals (vs 5- to 10-fold higher risk in those without epsilon4).
- These results suggest value in dementia surveillance for broad groups of cognitively impaired individuals beyond any specific category, and utility of APOE genotyping as a prognostic method.
Why it matters
In this population study, 46% of people with mild cognitive impairment at baseline converted to dementia within three years, compared with 3.3% of those without impairment. Carriers of at least one APOE epsilon 4 allele with cognitive impairment had a 22- to 25-fold higher risk of dementia than unimpaired individuals.
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Study details
- Participants120
- Effect size3.3%
- Evidence strengthLow
How this study scored 55/100
Published in a leading specialty journal. Scored zero for study design and randomised / blinded because the record does not state it. We have no data on senior author's track record, so that was left out: it earned 53 of the 96 points we could judge it on, which is 55 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | 4 / 4 | Neurology: journal h-index 525 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2006 — older than 20 years, still counted |
| Sample size | 2 / 4 | 120 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 | 5 / 7 | Cited 184 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 8.4 citations a year over 22 year(s) since 2006 |
| Impact for its field and year | 3 / 6 | Cited 6.9× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 21 other studies in this library |
| Still being cited | 2 / 4 | Cited 23 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | 2 / 3 | Johns Hopkins University: institution h-index 2,306 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 3 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 16864813) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 53 / 96 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 53 of the 96 points we could judge it on is 55 out of 100. |
| Total | 55 / 100 | — |
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May need a subscription Unpaywall, Europe PMC and OpenAlex found no free copy of the full text (checked 10 Oct 2026), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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APA 7th
Tschanz, J. T., Welsh-Bohmer, K. A., Lyketsos, C. G., Corcoran, C., Green, R. C., Hayden, K., et al. (2006). Conversion to dementia from mild cognitive disorder: the Cache County Study. Neurology. https://doi.org/10.1212/01.wnl.0000224748.48011.84
Vancouver
Tschanz JT, Welsh-Bohmer KA, Lyketsos CG, Corcoran C, Green RC, Hayden K, et al. Conversion to dementia from mild cognitive disorder: the Cache County Study. Neurology. 2006. doi:10.1212/01.wnl.0000224748.48011.84. PMID: 16864813.
BibTeX
@article{tschanz2006-16864813,
author = {Tschanz, J. T. and Welsh-Bohmer, K. A. and Lyketsos, C. G. and Corcoran, C. and Green, R. C. and Hayden, K. and Norton, M. C. and Zandi, P. P. and others},
title = {{Conversion to dementia from mild cognitive disorder: the Cache County Study}},
journal = {Neurology},
year = {2006},
doi = {10.1212/01.wnl.0000224748.48011.84},
pmid = {16864813},
url = {https://doi.org/10.1212/01.wnl.0000224748.48011.84}
}
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