28,580 Alzheimer's and dementia studies in plain English, each scored out of 100.
Of 285 participants randomized (suvorexant, N = 142; placebo, N = 143), 277 (97%) completed the trial (suvorexant, N = 136; placebo, N = 141). 4 key findings →
Participants: 142 Evidence: high
Full summary, score breakdown and related studies → Original source
In total, 30 studies were included comprising 14,997 subjects. 5 key findings →
Participants: 14,997 Evidence: low
Full summary, score breakdown and related studies → Original source
Study objectives Mounting evidence implicates disturbed sleep or lack of sleep as one of the risk factors for Alzheimer's disease (AD), but the extent of the risk is uncertain. 4 key findings →
Design: systematic review Participants: 69,216 Evidence: high
Full summary, score breakdown and related studies → Original source
Sleep disorders, particularly insomnia and obstructive sleep apnea, are increasingly implicated as significant contributors to cognitive decline, dementia, and neurodegenerative diseases such as Alzheimer's disease (AD) and vascular cognitive impairment and dementia (VCID). 4 key findings →
Design: meta-analysis Evidence: high
Full summary, score breakdown and related studies → Original source
A relationship between sleep disorders and cognitive dysfunctions was reported in Parkinson's Disease (PD), however, some studies did not confirm the link. 4 key findings →
Design: meta-analysis Participants: 54 Evidence: high
Full summary, score breakdown and related studies → Original source
Fifty-nine primary studies met all criteria. 5 key findings →
Design: meta-analysis Evidence: high
Full summary, score breakdown and related studies → Original source
Sleep duration had an inverted U-shape relationship with cognitive scores (P <.001); and sleep quality had a positive linear relationship with cognitive scores (P <.001). 5 key findings →
Design: longitudinal study Participants: 10,768 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Midlife insomnia (fully adjusted hazard ratio = 1.24, 95% confidence interval = 1.02-1.50) and late-life terminal insomnia (fully adjusted odds ratio = 1.94, 95% confidence interval = 1.08-3.49) were associated with a higher dementia risk. 3 key findings →
Design: longitudinal study Participants: 1,446 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Smoking, head injury, pesticide exposure, and farming are potential risk factors for idiopathic REM sleep behavior disorder. 1 key finding →
Design: case-control study Participants: 694 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Nocturnal hypoxemia was related to greater decline on the 3 MS . 5 key findings →
Design: longitudinal study Participants: 2,636 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Insomnia in elderly people has traditionally been regarded as inevitable and trivial. 2 key findings →
Design: longitudinal study Participants: 705 Evidence: moderate
Full summary, score breakdown and related studies → Original source
During a median of 10.8 years follow-up, sleeping more or fewer than 7 hours was associated with a higher dementia risk (hazard ratio [HR] for 5 vs 7 hours: 1.35, 95% confidence interval [CI] 1.11-1.64; HR for 9 vs 7 hours: 1.59; 95% CI 1.37-1.85) as was daytime napping (HR for often/all of the time vs never/rarely: 1.67; 95% CI 1.37-2.03). 4 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
We observed a dose-response association between higher alcohol consumption in 2006 and worse sleep quality in 2012 (Ptrend < 0·001), after adjusting for age, sex, socio-economic status, smoking status, physical activity, obesity, plasma lipid profiles, diabetes and hypertension. 5 key findings →
Design: cross-sectional Participants: 905 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Sleep duration exhibited a U-shaped association with SPARE-AD (p = 0.001), Trail Making Tests A and B, and the Digit Symbol Substitution Test (all p < 0.001). 5 key findings →
Participants: 38,816 Evidence: low
Full summary, score breakdown and related studies → Original source
The findings may help clinicians identify athletes who are at risk for worse impairments after a concussion due to preinjury sleep difficulties. 2 key findings →
Design: cohort study Participants: 348 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Increasing evidence links cognitive-decline and Alzheimer's disease (AD) to various sleep disorders, including obstructive sleep apnea (OSA). 3 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Baseline pRBD was associated with faster decline in global cognition and all cognitive domains, including verbal episodic memory, visuospatial ability, executive function, language, and processing speed. 5 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Furthermore, PET studies have revealed that Aβ accumulates in the healthy brain after a single night of sleep deprivation, suggesting that the human glymphatic pathway might also be primarily active during sleep. 3 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Dysfunction in 24-h circadian rhythms is a common occurrence in ageing adults; however, circadian rhythm disruptions are more severe in people with age-related neurodegenerative diseases, including Alzheimer's disease and related dementias, and Parkinson's disease. 1 key finding →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Prevalence of insomnia was 14%, 16%, and 11% for normal, MCI, and dementia groups. 5 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
The empirical study showed a U-shaped relationship between sleep duration and increased risk of cognitive impairment. 5 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
The final analytic sample included n = 2334 participants. 5 key findings →
Participants: 2,334 Evidence: low
Full summary, score breakdown and related studies → Original source
Methylation across all the CpGs strongly correlated with each other. 5 key findings →
Design: cross-sectional Participants: 96 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Around 40% of dementia risk is attributable to modifiable risk factors such as physical inactivity, hypertension, diabetes and obesity. 5 key findings →
Design: cohort study Evidence: moderate
Full summary, score breakdown and related studies → Original source
In IPTW, we observed a decreased risk of terminated healthspan for healthy sleep behaviors such as 'sleep duration 7-8h/d' (Hazard ratio, HR = 0.93; 95 % confidence interval, CI: 0.92-0.96; P < 0.001); 'morningness' (HR = 0.95; 95%CI: 0.93-0.98; P < 0.01); 'napping' (HR = 0.93; 95%CI: 0.91-0.94; P < 0.001); 'easy getting up from bed' (HR = 0.91; 95%CI: 0.88-0.93; P < 0.001); and, 'never/rarely experience sleeplessness/insomnia' (HR = 0.94; 95%CI: 0.92-0.96; P < 0.001). 5 key findings →
Participants: 590 Evidence: low
Full summary, score breakdown and related studies → Original source
Free full text links and the Full text may need a subscription label come from Unpaywall, Europe PMC and OpenAlex records of free copies, checked 10 Oct 2026. A study with neither is unknown, not paywalled. Show only studies that are free to read
This is alzhub's own score. It is not an official metric, not an impact factor, and no journal, publisher or ranking body endorses it. We built it so that a reader who is not a scientist can tell a landmark trial from a conference abstract without having to already know the difference. Every point comes from one of 20 components, all of them printed on the study itself, so you can disagree with our arithmetic rather than having to trust the total.
Journals are placed in ordered tiers, never given a numeric impact factor — we could not verify current impact factors from a source we control, and an invented one would be worse than none. Tier 1 is the top-tier general journals (NEJM, The Lancet, JAMA, Nature, Science, Nature Medicine); tier 2 is the leading specialty journals; tier 3 is every other peer-reviewed journal. A separate part scores how much the journal's own papers are cited, which tells the tier-3 journals apart.
Two rules we don't bend. First, we never fill in a missing value: if a record does not state a sample size or a design, that component scores zero, and if we simply have no data for a part, such as a citation count, that part is left out and the study is scored on the parts we could check. The study card says which. Second, anything that is not a peer-reviewed article is capped at 16/100 and carries a warning chip — so a conference abstract or a company press release can never outrank a peer-reviewed paper, no matter how good it looks.
We rank a rigorous null result — a good trial showing that something does not work — above an early positive finding. Someone deciding whether to buy a supplement is served by that, and the rigour is already counted by the design and journal components.
The score is computed from the published data alone and is reproducible: the same file always yields the same numbers.
See the whole rubric drawn out → — four charts covering all 28,580 studies: how the scores are spread and where the cap bites, which of the 20 components the library is strong and weak on, which subjects rest on stronger evidence, and what kinds of study each subject is actually built from.
This is a large sample of the Alzheimer's literature, not an exhaustive index of it. It holds 28,580 records, built mostly from automated pulls of Europe PMC (62.2% of the library) and OpenAlex (17.8%), plus smaller pulls from PubMed, Crossref and medRxiv. If a study, a drug, or a finding isn't here, that is not evidence it doesn't exist in the literature — it may simply not have been pulled in yet.
1,034 records (3.6% of the library) are not peer-reviewed — 962 of those are preprints posted before any journal review, and the rest are conference abstracts, regulatory notices and reports. Every study card on this page states its status plainly, and the score above is capped for anything that isn't a peer-reviewed article.
See the full, machine-readable breakdown of this library's coverage →