Yearly change in air pollution and brain aging among older adults: A community-based study in Taiwan

Ying-Cen Lin; Kang-Chen Fan; Chih-Da Wu; Wen-Chi Pan; Jiu-Chiuan Chen; Yi-Ping Chao; Yen-Jun Lai; Yen-Ling Chiu; Yi-Fang Chuang

doi:10.1016/j.envint.2024.108876

Yearly change in air pollution and brain aging among older adults: A community-based study in Taiwan

Environ Int. 2024 Aug:190:108876. doi: 10.1016/j.envint.2024.108876. Epub 2024 Jul 6.

Authors

Ying-Cen Lin¹, Kang-Chen Fan¹, Chih-Da Wu², Wen-Chi Pan³, Jiu-Chiuan Chen⁴, Yi-Ping Chao⁵, Yen-Jun Lai⁶, Yen-Ling Chiu⁷, Yi-Fang Chuang⁸

Affiliations

¹ School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
² Department of Geomatics, National Cheng Kung University, Tainan, Taiwan; National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan; Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, Taiwan; Research Center for Precision Environmental Medicine, Koahsiung Medical University, Koahsiung, Taiwan.
³ Institute of Environmental and Occupational Health Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan.
⁴ Departments of Population & Public Health Sciences and Neurology, University of Southern California, Keck School of Medicine, Los Angeles, CA, USA.
⁵ Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Computer Science and Information Engineering, Chang Gung University, Taoyuan, Taiwan; Department of Otorhinolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
⁶ Division of Medical Imaging, Department of Radiology, Far Eastern Memorial Hospital, New Taipei, Taiwan.
⁷ Department of Medical Research, Far Eastern Memorial Hospital, Taipei, Taiwan; Graduate Program in Biomedical Informatics and Graduate Institute of Medicine, Yuan Ze University, Taoyuan, Taiwan; Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan.
⁸ Institute of Public Health, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; International Health Program, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Psychiatry, Far Eastern Memorial Hospital, New Taipei, Taiwan; Health Innovation Center, National Yang Ming Chao Tung Univeristy, Taipei, Taiwan. Electronic address: chuangy@nycu.edu.tw.

PMID: 39002330
DOI: 10.1016/j.envint.2024.108876

Abstract

Background: Air pollution is recognized as a modifiable risk factor for dementia, and recent evidence suggests that improving air quality could attenuate cognitive decline and reduce dementia risk. However, studies have yet to explore the effects of improved air quality on brain structures. This study aims to investigate the impact of air pollution reduction on cognitive functions and structural brain differences among cognitively normal older adults.

Methods: Four hundred and thirty-one cognitively normal older adults were from the Epidemiology of Mild Cognitive Impairment study in Taiwan (EMCIT), a community-based cohort of adults aged 60 and older, between year 2017- 2021. Annual concentrations of PM_2.5, NO₂, O₃, and PM₁₀ at participants' residential addresses during the 10 years before enrollment were estimated using ensemble mixed spatial models. The yearly rate of change (slope) in air pollutants was estimated for each participant. Cognitive functions and structural brain images were collected during enrollment. The relationships between the rate of air pollution change and cognitive functions were examined using linear regression models. For air pollutants with significant findings in relation to cognitive function, we further explored the association with brain structure.

Results: Overall, all pollutant concentrations, except O₃, decreased over the 10-year period. The yearly rates of change (slopes) in PM_2.5 and NO₂ were correlated with better attention (PM_2.5: r = -0.1, p = 0.047; NO₂: r = -0.1, p = 0.03) and higher white matter integrity in several brain regions. These regions included anterior thalamic radiation, superior longitudinal fasciculus, inferior longitudinal fasciculus, corticospinal tract, and inferior fronto-occipital fasciculus.

Conclusions: Greater rate of reduction in air pollution was associated with better attention and attention-related white matter integrity. These results provide insight into the mechanism underlying the relationship between air pollution, brain health, and cognitive aging among older adults.

Keywords: Air pollution; Cognitive functions; Diffusion tensor imaging; Structural brain imaging.

MeSH terms

Aged
Aged, 80 and over
Aging / physiology
Air Pollutants* / analysis
Air Pollution* / statistics & numerical data
Brain*
Cognition
Cognitive Dysfunction / epidemiology
Cohort Studies
Environmental Exposure / statistics & numerical data
Female
Humans
Male
Middle Aged
Particulate Matter* / analysis
Taiwan

Substances

Air Pollutants
Particulate Matter