Cited by 209Air Quality and Health ImpactsDementia and Cognitive Impairment ResearchIndoor Air Quality and Microbial Exposure

Exposure to Air Pollution in Relation to Risk of Dementia and Related Outcomes: An Updated Systematic Review of the Epidemiological Literature

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Weuve, Jennifer, Bennett, Erin E., Ranker, Lynsie, Gianattasio, Kan Z., Pedde, Meredith, Adar, Sara D., Yanosky, Jeff D., Power, Melinda C.·2021·Environmental Health Perspectives

Abstract

BACKGROUND: Dementia is a devastating neurologic condition that is common in older adults.We previously reviewed the epidemiological evidence examining the hypothesis that long-term exposure to air pollution affects dementia risk.Since then, the evidence base has expanded rapidly.OBJECTIVES: With this update, we collectively review new and previously identified epidemiological studies on air pollution and late-life cognitive health, highlighting new developments and critically discussing the merits of the evidence.METHODS: Using a registered protocol (PROSPERO 2020 CRD42020152943), we updated our literature review to capture studies published through 31 December 2020, extracted data, and conducted a bias assessment.RESULTS: We identified 66 papers (49 new) for inclusion in this review.Cognitive level remained the most commonly considered outcome, and particulate matter (PM) remained the most commonly considered air pollutant.Since our prior review, exposure estimation methods in this research have improved, and more papers have looked at cognitive change, neuroimaging, and incident cognitive impairment/dementia, though methodological concerns remain common.Many studies continue to rely on administrative records to ascertain dementia, have high potential for selection bias, and adjust for putative mediating factors in primary models.A subset of 35 studies met strict quality criteria.Although high-quality studies of fine particulate matter with aerodynamic diameter ≤2:5 lm (PM 2:5 ) and cognitive decline generally supported an adverse association, other findings related to PM 2:5 and findings related to particulate matter with aerodynamic diameter ≤10 lm (PM 10 , NO 2 , and NO x ) were inconclusive, and too few papers reported findings with ozone to comment on the likely direction of association.Notably, only a few findings on dementia were included for consideration on the basis of quality criteria.DISCUSSION: Strong conclusions remain elusive, although the weight of the evidence suggests an adverse association between PM 2:5 and cognitive decline.However, we note a continued need to confront methodological challenges in this line of research.

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  • Studies specific to dementia and related outcomes have reported that higher long-term exposure to PM2.5 is associated with worse cognitive decline, reduced brain volumes and increased rates of incident dementia.

    “Studies specific to dementia and related outcomes have reported that higher long‐term exposure to PM2.5 is associated with worse cognitive decline, 179 , 220 reduced brain volumes 179 and increased rates of incident (newly onset) dementia. 220 , 221 , 222”

    From 2024 Alzheimer's disease facts and figures (2024) · cites this paper as [179]

    In Results > Summary of Study Findings (page not available), the review reports adverse associations between PM2.5 and cognitive decline and a tendency toward smaller brain volumes with higher exposure. It also says the brain-volume estimates were often imprecise and associations with incident cognitive impairment or dementia were less consistent, so the unqualified claim of increased incident dementia rates overstates the evidence. (LLM, conf=0.86)

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  • Higher long-term exposure to fine particulate matter air pollution is associated with worse cognitive decline.

    “Higher levels of long-term exposure to fine particulate matter air pollution are associated with worse cognitive decline.166,200”

    From 2023 Alzheimer's disease facts and figures (2023) · cites this paper as [166]

  • The strongest effect found in that review was with respect to PM2.5 and cognitive decline.

    “The strongest effect found was with respect to PM2.5 and cognitive decline.”
  • There is growing evidence that exposure to air pollutants may be detrimental to the central nervous system and contribute to deficits in cognitive development, neurodegenerative diseases and dementia.

    “There is also growing evidence that exposure to air pollutants maybe detrimental to the central nervous system and contribute to deficits in cognitive development, neurodegenerative diseases and dementia [112, 113].”
  • A recent review found only suggestive evidence that air pollution may influence late-life cognitive health because there is still substantial heterogeneity of findings across studies.

    “A recent review [113] found that, despite a substantial increase in publications, there is only suggestive evidence that air pollution may influence late-life cognitive health as there is still substantial heterogeneity of findings across the studies.”

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1 retracted

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Research works printed but not linked: 2

  1. U.S. EPA (U.S. Environmental Protection Agency). 2009. Integrated science assessment for particulate matter. EPA/600/R-15/068. Washington, DC: U.S. Environmental Protection Agency 36630543
  2. U.S. EPA. 2019. Integrated science assessment (ISA) for particulate matter (final report, 2019). EPA/600/R-19/188. Washington, DC: U.S. Environmental Protection Agency 36630543

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Authors
Weuve, J., Bennett, E. E., Ranker, L., Gianattasio, K. Z., Pedde, M., Adar, S. D., Yanosky, J. D., & Power, M. C.
Affiliations
  • Boston University (US)
  • George Washington University (US)
  • University of Michigan (US)
  • Pennsylvania State University (US)
Corresponding author
Power, Melinda C.
Venue
Environmental Health Perspectives
Published
2021-09
Volume
129
Issue
9
Pages
96001-96001
ISSN
  • 0091-6765 (ISSN-L)
  • 1552-9924
OpenAlex
W3199357056
Cited by
209
References
152
Citations by year
2026: 26 · 2025: 56 · 2024: 49 · 2023: 36 · 2022: 36 · 2021: 6
FWCI
3.02
Type
journal article
Language
en
Open access
Licence
public-domain
Locations
  • Environmental Health Perspectives (publishedVersion, public-domain)
  • Europe PMC (PubMed Central) (publishedVersion, other-oa)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Alzheimer's Association
  • Health Effects Institute
  • National Institute on Aging (R01AG067497, R01AG065359, R01AG051125, R01AG030153)
  • National Institute of Environmental Health Sciences (R01ES028694, R01ES029509)
Topics
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Air Quality and Health Impacts
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Indoor Air Quality and Microbial Exposure
Keywords
air pollution, dementia, cognitive decline, particulate matter, PM2.5, PM10, nitrogen dioxide, ozone, exposure assessment, selection bias, neuroimaging, cognitive impairment
MeSH terms
Aged, Air Pollutants, Air Pollution, Dementia, Environmental Exposure, Humans, Particulate Matter

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