Home › Research › Cognitive tests and assessment
Inflammation as a mediator of air pollution's role in Alzheimer's disease and related dementias
Bo Zhao, Chaofan Geng, Shaojiong Zhou, Tao Wei, Aonan Li, Yiwei Zhao, Yi Tang. Journal of Alzheimer s Disease, 2025-12-29
Topic: Amyloid, tau and blood-test diagnosis
Background Air pollution has been implicated in cognitive decline and increased risk of Alzheimer's disease (AD) and Alzheimer's disease–related dementias (ADRD). Inflammation, particularly C-reactive protein (CRP), may mediate these associations, but causal evidence remains limited. Objective To examine the associations between particulate matter (PM) exposure and cognitive performance, evaluate the causal effects of air pollutants on genetically predicted AD/ADRD risk using Mendelian randomization (MR), and assess CRP as a potential mediator. Methods We conducted observational analyses among 7087 older adults from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) to evaluate associations between long-term PM exposure and Mini-Mental State Examination (MMSE) scores. Two-sample MR using GWAS summary statistics was performed to estimate the causal effects of PM 2.5 , PM 10 , NO 2 , and NO x on AD risk. Mediation MR assessed CRP's contribution to the PM–AD pathway. Results Higher exposure to finer PM was associated with lower MMSE scores, with the strongest associations observed for PM 1 (β = −0.335; 95% CI: −0.624 to −0.263) and PM 2.5 (β = −0.229; 95% CI: −0.367 to −0.164). MR analyses identified a causal effect of PM 10 on AD risk (OR = 1.926; 95% CI: 1.032–3.598). CRP mediated 42.9% of this effect (p = 0.003). Conclusions Long-term PM exposure, particularly PM 10 , may contribute to increased AD/ADRD susceptibility, potentially through inflammation-related pathways. Finer particles showed stronger observational associations with cognitive decline, highlighting the need for further investigation. These findings support air quality improvement and inflammation-targeted strategies for dementia prevention.
Key findings
- Background Air pollution has been implicated in cognitive decline and increased risk of Alzheimer's disease (AD) and Alzheimer's disease–related dementias (ADRD).
- Results Higher exposure to finer PM was associated with lower MMSE scores, with the strongest associations observed for PM 1 (β = −0.335; 95% CI: −0.624 to −0.263) and PM 2.5 (β = −0.229; 95% CI: −0.367 to −0.164).
- These findings support air quality improvement and inflammation-targeted strategies for dementia prevention.
Why it matters
This study found that higher exposure to fine particulate matter was associated with lower MMSE scores, and Mendelian randomization identified a causal effect of PM10 on Alzheimer's disease risk. CRP mediated 42.9% of this effect, supporting air quality improvement and inflammation-targeted strategies for dementia prevention.
Study details
- Study designlongitudinal study
- Effect sizeOR = 1.926; 42.9%
- Evidence strengthModerate
How this study scored 43/100
Published in a peer-reviewed journal, and it is a longitudinal study following the same people over time. Scored zero for sample size, studied in people and randomised / blinded because the record does not state it. We have no data on senior author's track record, so that was left out: it earned 41 of the 96 points we could judge it on, which is 43 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of Alzheimer s Disease) |
| Journal's citation record | 2 / 4 | Journal of Alzheimer s Disease: journal h-index 218 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 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 | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 1 / 7 | Cited 1 times (OpenAlex, 2026-10-10) |
| Citations per year | 0 / 5 | 0.3 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 1 / 6 | Cited 0.4× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 0 / 4 | Cited 1 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | — / 4 | OpenAlex's profile for last-listed author Yi Tang holds only 1 work(s), too few to judge a track record — left out of this score |
| Institution's track record | 0 / 3 | Capital Medical University: institution h-index 643 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 3 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 41460601) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 41 / 96 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 41 of the 96 points we could judge it on is 43 out of 100. |
| Total | 43 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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 names 7 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
APA 7th
Zhao, B., Geng, C., Zhou, S., Wei, T., Li, A., Zhao, Y., et al. (2025). Inflammation as a mediator of air pollution's role in Alzheimer's disease and related dementias. Journal of Alzheimer s Disease. https://doi.org/10.1177/13872877251408422
Vancouver
Zhao B, Geng C, Zhou S, Wei T, Li A, Zhao Y, et al. Inflammation as a mediator of air pollution's role in Alzheimer's disease and related dementias. Journal of Alzheimer s Disease. 2025. doi:10.1177/13872877251408422. PMID: 41460601.
BibTeX
@article{zhao2025-41460601,
author = {Zhao, Bo and Geng, Chaofan and Zhou, Shaojiong and Wei, Tao and Li, Aonan and Zhao, Yiwei and Tang, Yi},
title = {{Inflammation as a mediator of air pollution's role in Alzheimer's disease and related dementias}},
journal = {Journal of Alzheimer s Disease},
year = {2025},
doi = {10.1177/13872877251408422},
pmid = {41460601},
url = {https://doi.org/10.1177/13872877251408422}
}
Studies this one cites
Referenced by this study and also in the alzhub library, so you can read them here.
Related studies in Cognitive tests and assessment
Also tagged “amyloid-beta”
1,339 studies in the library carry the topic tag “amyloid-beta”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 1,339 tagged studies.