Impact of Long-Term Exposure to Air Pollution on Cognitive Decline in Older Adults Without Dementia

Article type: Research Article

Authors: Park, Seon Young^a | Han, Jiyeon^b | Kim, Seon Hwa^c | Suk, Hye Won^d | Park, Jee Eun^{a; e; f; *} | Lee, Dong Young^{a; c; e; g; h}

Affiliations: [a] Department of Neuropsychiatry, Seoul National University Hospital, Seoul, South Korea | [b] Medical Research Collaborating Center, Seoul National University Hospital, Seoul, South Korea | [c] Seoul Metropolitan Center for Dementia, Seoul, South Korea | [d] Departement of Psychology, Sogang University, Seoul, South Korea | [e] Department of Psychiatry, Seoul National University College of Medicine, Seoul, South Korea | [f] Jongno Community Center for Dementia, Seoul, South Korea | [g] Medical Research Center, Institute of Human Behavioral Medicine, Seoul National University, Seoul, South Korea | [h] Interdisiplinary Program in Cognitive Science, Seoul National University, Seoul, South Korea

Correspondence: [*] Correspondence to: Jee Eun Park, MD, PhD, Department of Psychiatry, Seoul National University College of Medicine, 101, Daehak-ro, Jongno-gu, Seoul, South Korea. Tel.: +82 2 2072 3155; Fax: +82 2 733 7241; E-mail: parkim80@snu.ac.kr.

Abstract: Background:Air pollution control is necessary to decrease the burden on older adults with cognitive impairment, especially in low- and middle-income countries (LMICs). Objective:This study retrospectively examined the effect of cumulative exposure to air pollution, including NO2, SO2, CO, fine particulate matter (PM)10, PM2.5, and O3, on cognitive function in older individuals. Methods:Community-dwelling older adults who underwent the Mini-Mental State Examination (MMSE) from 2007 to 2018 were included in the analyses. We excluded older individuals diagnosed with dementia at baseline, while those who had completed more than two MMSE tests were included in the longitudinal analyses. Baseline MMSE and changes in MMSE scores were analyzed according to 5-year average concentrations of the district-level air pollutants, after controlling for covariates associated with cognitive decline in older adults. Results:In total, 884,053 (74.3±7.1 years; 64.1% females) and 398,889 (72.3±6.4 years; 67.0% females) older individuals were included in the cross-sectional and longitudinal analyses, respectively. Older individuals exposed to higher levels of NO2, SO2, CO, and PM10 showed lower baseline MMSE scores. During follow-up, exposure to higher levels of NO2, SO2, CO, and PM10 was associated with greater decreases in MMSE scores in older individuals; for O3, the opposite pattern was observed. Conclusion:Our findings suggest that exposure to high levels of air pollutants can worsen the cognitive performance of older adults without dementia. Efforts to reduce air pollution in LMICs that have similar levels of pollutants to South Korea are necessary to reduce the burden on older adults with cognitive impairment.

Keywords: Air pollution, cognition, cognitive decline, older adults, South Korea

DOI: 10.3233/JAD-215120

Journal: Journal of Alzheimer's Disease, vol. 86, no. 2, pp. 553-563, 2022