Bi-directional association between outdoor or social activities and cognitive function: do the PM2.5 exposure catalyze the detrimental inactivity-poor cognition cycle?

Yuling Jiang; Yifei Wu; Yang Hu; Shaojie Li; Longbin Ren; Jingjing Wang; Mingzhi Yu; Rui Yang; Zhouwei Liu; Nan Zhang; Kejia Hu; Yunquan Zhang; Gill Livingston; Junfeng Jim Zhang; Yi Zeng; Huashuai Chen; Yao Yao

doi:10.1016/j.envres.2024.118868

Bi-directional association between outdoor or social activities and cognitive function: do the PM_2.5 exposure catalyze the detrimental inactivity-poor cognition cycle?

Environ Res. 2024 Apr 3;252(Pt 1):118868. doi: 10.1016/j.envres.2024.118868. Online ahead of print.

Authors

Yuling Jiang¹, Yifei Wu², Yang Hu³, Shaojie Li¹, Longbin Ren³, Jingjing Wang³, Mingzhi Yu¹, Rui Yang³, Zhouwei Liu¹, Nan Zhang⁴, Kejia Hu⁵, Yunquan Zhang⁶, Gill Livingston⁷, Junfeng Jim Zhang⁸, Yi Zeng⁹, Huashuai Chen¹⁰, Yao Yao¹¹

Affiliations

¹ School of Public Health, Peking University, Beijing, China; China Center for Health Development Studies, Peking University, Beijing, China.
² School of Public Health, Peking University, Beijing, China.
³ China Center for Health Development Studies, Peking University, Beijing, China.
⁴ Manchester Urban Ageing Research Group (MUARG), The University of Manchester, Manchester, UK.
⁵ School of Public Health, Zhejiang University, Hangzhou, China.
⁶ Department of Epidemiology and Biostatistics, School of Public Health, and Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Wuhan University of Science and Technology, Wuhan, China.
⁷ Division of Psychiatry, University College London, London, UK.
⁸ Global Health Institute and the Nicholas School of Environment, Duke University, Durham, NC, USA.
⁹ Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, China; Center for the Study of Aging and Human Development and Geriatrics Division, Medical School of Duke University, Durham, NC, USA.
¹⁰ Business School of Xiangtan University, Xiangtan, China. Electronic address: huashuai.chen@gmail.com.
¹¹ China Center for Health Development Studies, Peking University, Beijing, China; Key Laboratory of Epidemiology of Major Diseases (Peking University), Ministry of Education, Beijing, China; State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing, China. Electronic address: yao.yao@bjmu.edu.cn.

PMID: 38580003
DOI: 10.1016/j.envres.2024.118868

Abstract

Background: Previous research has shown that lack of leisure activities, either outdoor or social activities, impedes cognitive function. However, the interrelationship between poor cognition and deficient activities is understudied. In addition, whether exposure to air pollution, such as PM_2.5, can accelerate the detrimental 'inactivity-poor cognition' cycle, is worthy of investigation.

Methods: We used data from the 2008, 2011, 2014, and 2018 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We assessed the frequency of outdoor or social activities at each wave. The cognitive function was examined using a China-Modified Mini-mental State Examination. We estimated the residential exposure to fine particular matter (PM_2.5) via a satellite-based model. We applied cross-lagged panel (CLP) model to examine the bi-directional relationship between outdoor or social activities and cognitive function. We then examined the effect of PM_2.5 exposure with sequent cognitive function and activities using generalized estimation equation (GEE) model.

Findings: Overall, we observed significant bi-directional associations between outdoor or social activities and cognitive function. Participants with better cognitive function in the last wave were more likely to engage in outdoor or social activities in the following wave (outdoor activities: β = 0.37, 95% CI [0.27,0.48], P < 0.01; social activities: β = 0.05, 95% CI [0.02,0.09] P < 0.01). Meanwhile, higher engagement in outdoor or social activities in the last wave was associated with more favorable cognitive function in the following wave (outdoor activities: β = 0.06, 95% CI [0.03,0.09], P < 0.01; social activities: β = 0.10, 95% CI [0.03,0.18], P < 0.01). Notably, an increase in PM_2.5 exposure during the preceding year was significantly associated with a declining cognitive function (β = -0.05, 95% CI [-0.08,-0.03], P < 0.01), outdoor activities (β = -0.02, 95% CI [-0.04, -0.01], P < 0.01) and social activities (β = -0.02, 95% CI [-0.02, -0.01], P < 0.01) in the current year; the lagged effects of the PM_2.5 exposure in the past year of the last wave on activities and cognitive function of the following wave were also observed.

Interpretation: Our findings not only indicate the bi-directional links between the frequency of outdoor or social activities and cognitive function, but also report that PM_2.5 exposure plays a role in catalyzing the detrimental inactivity-poor cognition cycle. Future research should investigate whether the policy-driven interventions, such as clean air policies, can break the unfavorable activity-cognition cycle, and thereby promoting health from the dual gains in leisure activities and cognition.

Keywords: Air pollution; Bi-directional relationship; Cognitive functions; Leisure activities; Older adults.