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Long-term exposure to traffic-related particulate matter impairs cognitive function in the elderly
Ranft U, Schikowski T, Sugiri D, Krutmann J, Krämer U.. Environmental research, 2009-09-04
Topic: Risk, prevention and care in population studies
Animal studies have suggested that fine particulate matter (PM) can translocate from the upper respiratory tract to the brain and cause brain inflammation. Brain inflammation is involved in the pathogenesis of neurodegenerative diseases. Hypothesizing therefore that long-term exposure to fine PM might contribute to the development of Alzheimer's disease (AD), the objective of this study was to investigate the association between exposure to fine PM and mild cognitive impairment (MCI) which is associated with a high risk of progression to AD. A study group of 399 women aged 68-79 years who lived for more than 20 years at the same residential address has been assessed for long-term exposure to PM and tested for MCI. The exposure assessment comprised background concentration of PM(10) and traffic-related PM indicated by the distance of the residential address to the next busy road. The women were assessed for MCI by a battery of several neuropsychological tests and their odor identification ability. Consistent effects of traffic-related air pollution exposure on test performances including a dose-response relation were found. The associations were adjusted for potential confounders using regression analysis. These results indicate that chronic exposure to traffic-related PM may be involved in the pathogenesis of AD.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Ranft, U., Schikowski, T., Sugiri, D., Krutmann, J., & Krämer, U. (2009). Long-term exposure to traffic-related particulate matter impairs cognitive function in the elderly. Environmental research. https://doi.org/10.1016/j.envres.2009.08.003
Vancouver
Ranft U, Schikowski T, Sugiri D, Krutmann J, Krämer U. Long-term exposure to traffic-related particulate matter impairs cognitive function in the elderly. Environmental research. 2009. doi:10.1016/j.envres.2009.08.003. PMID: 19733348.
BibTeX
@article{ranft2009-19733348,
author = {Ranft, U. and Schikowski, T. and Sugiri, D. and Krutmann, J. and Krämer, U.},
title = {{Long-term exposure to traffic-related particulate matter impairs cognitive function in the elderly}},
journal = {Environmental research},
year = {2009},
doi = {10.1016/j.envres.2009.08.003},
pmid = {19733348},
url = {https://doi.org/10.1016/j.envres.2009.08.003}
}
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Key findings
- Animal studies have suggested that fine particulate matter (PM) can translocate from the upper respiratory tract to the brain and cause brain inflammation.
- Hypothesizing therefore that long-term exposure to fine PM might contribute to the development of Alzheimer's disease (AD), the objective of this study was to investigate the association between exposure to fine PM and mild cognitive impairment (MCI) which is associated with a high risk of progression to AD.
- These results indicate that chronic exposure to traffic-related PM may be involved in the pathogenesis of AD.
Why it matters
In 399 older women, long-term exposure to traffic-related particulate matter was associated with worse performance on cognitive tests, suggesting a possible link to mild cognitive impairment. This is an observational finding and does not prove that air pollution causes Alzheimer's disease or that reducing exposure prevents it.
Study details
- Evidence strengthLow
How this study scored 47/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Environmental research) |
| Journal's citation record | 3 / 4 | Environmental Research: journal h-index 259 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2009 — within 20 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 | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| 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 | 6 / 7 | Cited 414 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 21.8 citations a year over 19 year(s) since 2009 |
| Impact for its field and year | 3 / 6 | Cited 7.4× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 8 other studies in this library |
| Still being cited | 3 / 4 | Cited 54 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 3 / 4 | Last-listed author Ursula Krämer: h-index 75 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Heinrich Heine University Düsseldorf: institution h-index 794 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 2 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 19733348) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 47 / 100 | — |
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