Environmental greenspace, subjective well-being, and all-cause mortality in elderly Chinese: Association and mediation study in a prospective cohort

Qile He; Linxin Liu; Haofan Zhang; Runsen Chen; Guanghui Dong; Lijing L Yan; Yi Zeng; Yoonhee Kim; John S Ji

doi:10.1016/j.envres.2023.115732

Environmental greenspace, subjective well-being, and all-cause mortality in elderly Chinese: Association and mediation study in a prospective cohort

Environ Res. 2023 Jun 15:227:115732. doi: 10.1016/j.envres.2023.115732. Epub 2023 Mar 24.

Authors

Qile He¹, Linxin Liu², Haofan Zhang³, Runsen Chen², Guanghui Dong⁴, Lijing L Yan⁵, Yi Zeng⁶, Yoonhee Kim⁷, John S Ji⁸

Affiliations

¹ Institute of Medical Information/Medical Library, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
² Vanke School of Public Health, Tsinghua University, Beijing, China.
³ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, China.
⁴ Department of Occupational and Environmental Health, School of Public Health, Sun Yat-Sen University, Guangzhou, Guangdong, China.
⁵ Global Health Research Center, Duke Kunshan University, Kunshan, Jiangsu, China.
⁶ Center for Healthy Aging & Development, National School of Development, Peking University, Beijing, China; Center for the Study of Aging and Human Development, Duke University School of Medicine, Durham, NC, USA.
⁷ Department of Global Environmental Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. Electronic address: yoonheekim@m.u-tokyo.ac.jp.
⁸ Vanke School of Public Health, Tsinghua University, Beijing, China. Electronic address: johnji@tsinghua.edu.cn.

PMID: 36965791
DOI: 10.1016/j.envres.2023.115732

Abstract

Background: Subjective well-being (SWB) measures mental health and happiness. Greenspace can have a positive impact on mental health, and higher SWB is associated with lower all-cause mortality. We conducted a mediation analysis on greenspace and all-cause mortality through improving SWB, in a prospective cohort of Chinese older adults.

Methods: We included older adults over 65 from the 2008-2014 Chinese Longitudinal Healthy Longevity Survey (CLHLS). We used satellite-derived normalized difference vegetation index (NDVI) to measure greenspaces and calculated SWB measured by eight items. Three main statistical approaches were used. First, we used generalized estimating equations (GEE) and Cox proportional hazard models to examine NDVI-SWB and SWB-mortality relationships. Second, we conducted a causal mediation analysis to investigate the mediating effect of greenspace on all-cause mortality through SWB. Third, we conducted subgroup analyses to discover effect modification.

Findings: Among 13,133 participants, the mean SWB score and NDVI in 2008 were 28·9 (SD 4·34) and 0·41 (SD 0·14), respectively. We found SWB partially mediated the relationship between residential greenspace and mortality in the adjusted model (average causal mediation effect = 0·11, p = 0·04; average direct effect = 1·96, p < 0·001; total effect = 2·07, p < 0·001) with varying proportions in subgroups. The protective influence was more evident for people with impaired cognitive function, living in rural areas and towns, and with lower income.

Interpretation: We found a positive association between greenspace, SWB, and mortality. Greenness in the living environment confers better mental health and promotes longevity in the elderly population.

Keywords: Greenspace; Mediation analysis; Mortality; Subjective well-being.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Aged
Cities
East Asian People*
Humans
Longitudinal Studies
Mortality*
Parks, Recreational*
Prospective Studies

Grants and funding

P01 AG031719/AG/NIA NIH HHS/United States