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Sleep duration, cognitive decline, and dementia risk in older women
Chen JC, Espeland MA, Brunner RL, Lovato LC, Wallace RB, Leng X, Phillips LS, Robinson JG et al.. Alzheimer's & dementia : the journal of the Alzheimer's Association, 2015-06-15
Topic: Risk, prevention and care in population studies
Plain-language summary
Introduction Consistent evidence linking habitual sleep duration with risks of mild cognitive impairment (MCI) and dementia is lacking. Methods We conducted a prospective study on 7444 community-dwelling women (aged 65-80 y) with self-reported sleep duration, within the Women's Health Initiative Memory Study in 1995-2008. Incident MCI/dementia cases were ascertained by validated protocols. Cox models were used to adjust for multiple sociodemographic and lifestyle factors, depression, cardiovascular disease (CVD), and other clinical characteristics. Results We found a statistically significant (P = .03) V-shaped association with a higher MCI/dementia risk in women with either short (≤6 hours/night) or long (≥8 hours/night) sleep duration (vs. 7 hours/night). The multicovariate-adjusted hazard for MCI/dementia was increased by 36% in short sleepers irrespective of CVD, and by 35% in long sleepers without CVD. A similar V-shaped association was found with cognitive decline. Discussion In older women, habitual sleep duration predicts the future risk for cognitive impairments including dementia, independent of vascular risk factors.
What this study adds
Evidence grade: Low
This is a trial. Sleep was self-reported and the study shows an association only: it does not show that changing how long you sleep lowers dementia risk. Reported effect size: increased by 36%.
Taken from this record’s own fields, not from reading the paper. The grade is assigned from the abstract’s wording; what that means.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Chen, J. C., Espeland, M. A., Brunner, R. L., Lovato, L. C., Wallace, R. B., Leng, X., et al. (2016). Sleep duration, cognitive decline, and dementia risk in older women. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1016/j.jalz.2015.03.004
Vancouver
Chen JC, Espeland MA, Brunner RL, Lovato LC, Wallace RB, Leng X, et al. Sleep duration, cognitive decline, and dementia risk in older women. Alzheimer's & dementia : the journal of the Alzheimer's Association. 2016. doi:10.1016/j.jalz.2015.03.004. PMID: 26086180.
BibTeX
@article{chen2016-26086180,
author = {Chen, J. C. and Espeland, M. A. and Brunner, R. L. and Lovato, L. C. and Wallace, R. B. and Leng, X. and Phillips, L. S. and Robinson, J. G. and others},
title = {{Sleep duration, cognitive decline, and dementia risk in older women}},
journal = {Alzheimer's \& dementia : the journal of the Alzheimer's Association},
year = {2016},
doi = {10.1016/j.jalz.2015.03.004},
pmid = {26086180},
url = {https://doi.org/10.1016/j.jalz.2015.03.004}
}
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's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
Key findings
- Results We found a statistically significant (P = .03) V-shaped association with a higher MCI/dementia risk in women with either short (≤6 hours/night) or long (≥8 hours/night) sleep duration (vs. 7 hours/night).
Why it matters
In 7,444 women aged 65–80 followed in the Women's Health Initiative Memory Study, those who reported sleeping 6 hours or less a night had about a 36% higher adjusted risk of mild cognitive impairment or dementia than 7-hour sleepers, and those sleeping 8 hours or more had about a 35% higher risk if they did not have cardiovascular disease. Sleep was self-reported and the study shows an association only: it does not show that changing how long you sleep lowers dementia risk.
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Study details
- Effect sizeincreased by 36%
- Evidence strengthLow
How this study scored 68/100
Published in a leading specialty journal, and it is a randomized controlled trial. Scored zero for sample size 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 | 11 / 12 | A randomized controlled trial (from PubMed type “Randomized Controlled Trial”) |
| 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 | 2016 — within 20 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (pubmed indexes it as a clinical or observational study) |
| Randomized / blinded | 1 / 2 | Randomized (as stated in the record) |
| Times cited | 5 / 7 | Cited 249 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 20.8 citations a year over 12 year(s) since 2016 |
| Impact for its field and year | 4 / 6 | Cited 10.6× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 9 other studies in this library |
| Still being cited | 3 / 4 | Cited 76 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author W. Jerry Mysiw: h-index 41 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Harvard University: institution h-index 3,235 (OpenAlex) |
| Multicenter collaboration | 3 / 3 | OpenAlex lists 15 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 26086180) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 68 / 100 | — |
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