A total of 20 studies were included in the systematic review, and 17 provided data for the meta-analysis. 5 key findings →
Design: systematic review Participants: 20 Evidence: high
Full summary, score breakdown and related studies → Original source
Research
27,380 Alzheimer's and dementia studies in plain English, each scored out of 100.
Hearing loss is one of the top contributors to years lived with disability and is a risk factor for dementia. 3 key findings →
Design: meta-analysis Participants: 723,266 Evidence: high
Full summary, score breakdown and related studies → Original source
Our systematic review indicates that a majority of studies examining the vision-cognition relationship report that VI is associated with more cognitive decline, cognitive impairment or dementia among older adults. 4 key findings →
Design: systematic review Participants: 100 Evidence: high
Full summary, score breakdown and related studies → Original source
Seventeen risk/protective factors met criteria for the algorithm to estimate risk for any dementia including age, sex, education, hypertension, midlife obesity, midlife high cholesterol, diabetes, insufficient physical activity, depression, traumatic brain injury, atrial fibrillation, smoking, social engagement, cognitive engagement, fish consumption (diet), stroke, and insomnia. 5 key findings →
Design: meta-analysis Evidence: high
Full summary, score breakdown and related studies → Original source
Excluding participants with prevalent dementia, n = 1,161 individuals were included. 5 key findings →
Design: longitudinal study Participants: 1,161 Evidence: moderate
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
The present study showed that higher educational levels were related to better general cognitive function, executive function, memory, and information processing speed in PD patients, whereas no significant association was showed between educational levels and visuospatial function, language in PD patients. 4 key findings →
Design: meta-analysis Evidence: high
Full summary, score breakdown and related studies → Original source
70/100
In total, 20 articles were selected for review; 18 included results on the long-term effects of PM2.5 on dementia, 13 on AD, and eight on VaD. 5 key findings →
Design: systematic review Evidence: high
Full summary, score breakdown and related studies → Original source
Modifiable risk factors identified in this study, especially those with high-level evidence, should be considered in dementia prevention. 2 key findings →
Design: meta-analysis Evidence: high
Full summary, score breakdown and related studies → Original source
Long-term exposure to PM 2.5 contributed to the development of cognitive decline, which may be partly explained by brain amyloid accumulation indicative of increased AD risk. 1 key finding →
Design: cross-sectional Participants: 31,573 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Daily driving is a multi-faceted, real-world, behavioral measure of cognitive functioning requiring multiple cognitive domains working synergistically to complete this instrumental activity of daily living. 1 key finding →
Design: longitudinal study Participants: 186 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Social participation may theoretically decrease risk for mild cognitive impairment (MCI). 2 key findings →
Design: cross-sectional Participants: 32,715 Evidence: low
Full summary, score breakdown and related studies → Original source
In total, 6,683 participants were included. 5 key findings →
Design: cross-sectional Participants: 6,683 Evidence: low
Full summary, score breakdown and related studies → Original source
In the incident depression group, there was a mild decline in cognitive scores from baseline to the visit before depression onset compared with the never-depressed group. 5 key findings →
Design: longitudinal study Participants: 96 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Both objective and perceived social isolations were associated with future cognitive decline and increase risk of Alzheimer's disease (AD). 5 key findings →
Design: longitudinal study Participants: 23 Evidence: moderate
Full summary, score breakdown and related studies → Original source
This study included 407 participants (96 Thal, 405 Braak, and 406 CERAD). 4 key findings →
Design: cross-sectional Participants: 407 Evidence: low
Full summary, score breakdown and related studies → Original source
Growing evidence has linked long-term fine particulate matter (PM 2.5 ) exposure to neurological disorders. 2 key findings →
Design: cohort study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Caregivers showed a greater discrepancy in sleep duration than did noncaregivers (-0.46 hour vs 0.22 hour, respectively; P = .003). 5 key findings →
Design: cross-sectional Participants: 122 Evidence: low
Full summary, score breakdown and related studies → Original source
Investigators/staff from 85 (of 192 cohorts) responded; 6 (7%) excluded participants with severe impairment; 80 (94%) measured hearing and/or vision impairment, while 5 (6%) measured neither. 4 key findings →
Design: cohort study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Among 113,511 participants (mean age: 56.8 ± 8.09 years, female: 54.4%), a total number of 1,135 (1.00%) cases of incident dementia were identified during a median follow up period of 11.1 years [interquartile range (IQR): 10.9-11.4 years]. 4 key findings →
Participants: 500,000 Evidence: low
Full summary, score breakdown and related studies → Original source
The ε4 allele of the apolipoprotein E gene (APOE4) is a strong genetic risk factor for Alzheimer's disease (AD) and several other neurodegenerative conditions, including Lewy body dementia (LBD). 5 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source Free full text
Beneficiaries included 2,713,573 White, 251,958 Black, 196,845 Hispanic, 95,719 Asian, 11,727 American Indian/Alaska Native, and 63,795 of other race/ethnicity. 5 key findings →
Design: retrospective cohort Participants: 3,333,617 Evidence: moderate
Full summary, score breakdown and related studies → Original source Free full text
In cognitively unimpaired (CU) adults at baseline, the risk for progression to dementia increased for every decile increase in the ADI state ranking (hazard ratio = 1.06, 95% confidence interval (1.01-1.11), P = .01). 5 key findings →
Participants: 4,699 Evidence: low
Full summary, score breakdown and related studies → Original source Free full text
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
Where “Free full text” comes from
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
How the 0–100 score works — and why some entries are capped
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.
- Journal tier up to 10 pts
- Journal's citation record up to 4 pts
- Study design up to 12 pts
- Strength of evidence up to 5 pts
- Peer-review validation up to 10 pts
- How recent up to 5 pts
- Sample size up to 4 pts
- Effect reported up to 3 pts
- Studied in people up to 3 pts
- Randomised / blinded up to 2 pts
- Times cited up to 7 pts
- Citations per year up to 5 pts
- Impact for its field and year up to 6 pts
- Cited by studies here up to 6 pts
- Still being cited up to 4 pts
- Senior author's track record up to 4 pts
- Institution's track record up to 3 pts
- Multi-centre collaboration up to 3 pts
- Indexed in PubMed up to 2 pts
- Free to read up to 2 pts
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 27,380 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.
What this library is — and isn't
This is a large sample of the Alzheimer's literature, not an exhaustive index of it. It holds 27,380 records, built mostly from automated pulls of Europe PMC (60.6% of the library) and OpenAlex (18.6%), 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.
1,032 records (3.8% 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 →