A total of 19 reviews containing 37 meta-analyses were included umbrella review. 5 key findings →
Design: systematic review Participants: 19 Evidence: high
Full summary, score breakdown and related studies → Original source Free full text
Research
27,380 Alzheimer's and dementia studies in plain English, each scored out of 100.
Air pollution is a modifiable and preventable factor, and it is a possible risk factor for dementia. 4 key findings →
Design: systematic review Evidence: high
Full summary, score breakdown and related studies → Original source
We found no evidence that exposure to road traffic noise, either independently or in combination with traffic air pollution, was associated with risk of dementia in our study area. 5 key findings →
Design: longitudinal study Participants: 1,721 Evidence: moderate
Full summary, score breakdown and related studies → Original source
68/100
This study included 5646 participants (mean age 76 years, 65% female). 5 key findings →
Design: longitudinal study Participants: 5,646 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Current evidence for an association between ambient ozone exposure and mental health outcomes is inconclusive and further high quality studies are needed to assess any potential links given the strong biologic plausibility. 2 key findings →
Design: systematic review Evidence: high
Full summary, score breakdown and related studies → Original source
Increased exposure to urban green space was associated with reduced incidence of dementia and stroke. 3 key findings →
Design: cohort study Participants: 219,013 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Distinct associations between different traffic noise exposures and incident dementia subtypes were found in this large UK prospective cohort study. 3 key findings →
Design: cohort study Participants: 502,416 Evidence: moderate
Full summary, score breakdown and related studies → Original source Free full text
SDI score (aHR = 1.08; 95% CI 0.96, 1.22), joint air pollution (aHR = 1.03, 95% CI 0.92, 1.16) and joint SDI with air pollution (aHR = 1.04, 95% CI 0.89, 1.22) were not associated with dementia risk. 5 key findings →
Participants: 5,397 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Air pollution is one of the most serious environmental problems that afflict our planet and one of the greatest risk factors for human health. 3 key findings →
Design: systematic review Participants: 20 Evidence: high
Full summary, score breakdown and related studies → Original source Full text may need a subscription
Our findings suggest a potential protective role of green spaces on mental health (depression and anxiety) in adults, but further studies, especially longitudinal studies, are needed to provide further evidence of these benefits and of the mediation role of exposures like air pollution and noise. 5 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Air pollution may cause inflammatory and oxidative stress damage to the brain, leading to neurodegenerative disease. 4 key findings →
Participants: 680 Evidence: low
Full summary, score breakdown and related studies → Original source Free full text
Among the air toxics, higher 1,3-butadiene levels we estimated a hazard ratio of 1.12 (95 % CI: 1.00, 1.25) for incident dementia/CIND per IQR increase in 1,3-butadiene exposures. 5 key findings →
Participants: 1,612 Evidence: low
Full summary, score breakdown and related studies → Original source
During the study period, there were 1175 DDE hospital admissions. 1 key finding →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
The associations of particulate matter (PM) pollution with the morbidity of overall and subtypes of mental disorders (MDs), as well as the corresponding morbidity burden, remain understudied, especially in developing countries. 5 key findings →
Participants: 10,947 Evidence: low
Full summary, score breakdown and related studies → Original source
Between 1961 and 1971, military herbicides were used by the United States and allied forces for military purposes. 3 key findings →
Participants: 111,726 Evidence: low
Full summary, score breakdown and related studies → Original source
47/100
Animal studies have suggested that fine particulate matter (PM) can translocate from the upper respiratory tract to the brain and cause brain inflammation. 3 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source Full text may need a subscription
We had a follow-up of 71 million person-years. 5 key findings →
Evidence: moderate
Full summary, score breakdown and related studies → Original source
Air pollution is a risk factor for cardiovascular and Alzheimer's disease (AD). 3 key findings →
Participants: 72 Evidence: low
Full summary, score breakdown and related studies → Original source
45/100
The scientific literature is scarce when referring to the influence of atmospheric pollutants on neurodegenerative diseases for present and future climate change scenarios. 2 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Millions of Mexico, US and across the world children are overweight and obese. 5 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source Full text may need a subscription
Respiratory viruses have a significant impact on health, as highlighted by the COVID-19 pandemic. 4 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Exposures to fine particulate matter (PM 2.5 ) and ozone (O 3 ) above USEPA standards are associated with Alzheimer's disease (AD) risk. 4 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Traffic-related air pollution (TRAP) has been a common public health problem, which is associated with central nervous system dysfunction according to large-scale epidemiological studies. 4 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Endocrine-disrupting chemicals (EDCs) target the endocrine system by interfering with the natural hormones in the body leading to adverse effects on human and animal health. 5 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Exposure to air pollutants is associated with an increased risk of developing Alzheimer's disease (AD). 4 key findings →
Participants: 13 Evidence: low
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 →