Evidence is emerging that greater exposure to airborne pollutants is associated with increased risk of dementia. 2 key findings →
Design: longitudinal study Evidence: moderate
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.
PM2.5 exposure may contribute to WM loss in older women. 2 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
Air pollution exposure may exacerbate AD development. 5 key findings →
Design: systematic review Evidence: high
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
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
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
Higher chronic exposure to SO2 was associated with a faster decline in memory score, whereas chronic exposure to CO, NO2 , and PM10 were not associated with the rate of cognitive decline. 4 key findings →
Design: longitudinal study Participants: 269 Evidence: moderate
Full summary, score breakdown and related studies → Original source
We also identified several common challenges. 2 key findings →
Design: systematic review Evidence: high
Full summary, score breakdown and related studies → Original source
Between Jan 1, 2000, and Dec 31, 2016, of 63 038 019 individuals who were aged 65 years or older during the study period, we identified 1·0 million cases of Parkinson's disease and 3·4 million cases of Alzheimer's disease and related dementias based on primary and secondary diagnosis billing codes. 1 key finding →
Design: cohort study Participants: 19 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Strong conclusions remain elusive, although the weight of the evidence suggests an adverse association between PM2.5 and cognitive decline. 1 key finding →
Evidence: low
Full summary, score breakdown and related studies → Original source
The PSI was higher in Kaohsiung and compared with Pingtung patients, Kaohsiung patients were exposed to higher average annual concentrations of CO, NO2, PM10, and SO2. 5 key findings →
Design: case-control study Participants: 704 Evidence: moderate
Full summary, score breakdown and related studies → Original source
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
63/100
Evidence regarding the association of specific air pollutants with vascular dementia (VaD) risk is limited. 4 key findings →
Design: case-control study Participants: 831 Evidence: moderate
Full summary, score breakdown and related studies → Original source
In cognitively unimpaired adults with increased risk for AD, increased exposure to air pollution was suggested to be associated with greater global atrophy and reduced volume and thickness in specific brain areas known to be affected in AD, thus suggesting a potential link between environmental exposures and cerebral vulnerability to AD. 4 key findings →
Design: prospective cohort Participants: 958 Evidence: moderate
Full summary, score breakdown and related studies → Original source
62/100
Our results showed a positive association between exposure to NOx and O 3 and hospitalization for dementia and a negative association between NO 2 exposure and hospitalization for dementia. 5 key findings →
Participants: 350,844 Evidence: moderate
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
Modeling estimated single-year exposure, each 1 μg/m3 higher ambient PM2.5 was associated with 67% higher adjusted risk of incident dementia (hazard ratio [HR] = 1.669, 95% credible interval [CI]: 1.298, 2.136) and 75% higher adjusted risk of incident MCI (HR = 1.746, 95% CI: 1.518, 2.032). 4 key findings →
Participants: 1,572 Evidence: moderate
Full summary, score breakdown and related studies → Original source
61/100
Recent studies suggested that long-term exposure to fine particulate matter (PM2.5) was related to a higher risk of dementia incidence or hospitalizations in western populations, but the evidence is limited in Asian cities. 3 key findings →
Participants: 66,820 Evidence: moderate
Full summary, score breakdown and related studies → Original source
Long-term exposure to the highest tertile of PM10 or ozone was significantly associated with an increased risk of AD and VaD. 2 key findings →
Design: case-control study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Our findings raise concerns about potential effects of air pollution from traffic and other sources on the risk of PD, particularly in populations with high or increasing exposures. 3 key findings →
Design: case-control study Evidence: moderate
Full summary, score breakdown and related studies → Original source
Higher TRAP-NOx was associated with incident dementia (HR = 1.55 for the highest versus lower tertiles, 95% CI = 1.04, 2.55). 5 key findings →
Participants: 1,564 Evidence: moderate
Full summary, score breakdown and related studies → Original source
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
Endocrine disrupting chemicals (EDC) are released into environment from different sources. 3 key findings →
Evidence: low
Full summary, score breakdown and related studies → Original source
If the associations we observed are causal, then air pollution from residential wood burning, and air pollution from traffic, might be independent important risk factors for dementia. 3 key findings →
Design: longitudinal study Evidence: moderate
Full summary, score breakdown and related studies → Original source
These data suggest that beta-HCH is associated with a diagnosis of PD. 4 key findings →
Design: case-control study Participants: 20 Evidence: moderate
Full summary, score breakdown and related studies → Original source
From across this tag
9 of the 237 studies in this tag, picked by a fixed rule (a hash of each study's address), not by score or date; each page of this list shows a different 9. The same 9 appear here every time.
- A review of respirable fine particulate matter (PM 2.5 )-induced brain damage
- Prenatal Pesticide Exposure and Early Alzheimer Disease-Related Biomarker and Cognitive Changes in Midlife
- Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the US
- Association between exposure to air pollution and hippocampal volume in adults in the UK Biobank
- Road traffic noise, air pollution, and risk of dementia - results from the Betula project
- Glyphosate’s Suppression of Cytochrome P450 Enzymes and Amino Acid Biosynthesis by the Gut Microbiome: Pathways to Modern Diseases
- [Breathing: Ambient Air Pollution and Health - Part III]
- Long-term particulate matter 2.5 exposure and dementia: a systematic review and meta-analysis
- Dementia Around the World and the Latin America and Mexican Scenarios
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 →