Exposure to blue space surroundings and depressive symptoms in young Chinese adults: The mediating role of sleep

Jialian Li; Jing Hou; Li Zhang; Siqi Dou; Liu Yang; Victor Teng; Chengshuai Zhang; Hongwei Sun; Peng Lu; Yuming Guo

doi:10.1016/j.envres.2023.117765

Exposure to blue space surroundings and depressive symptoms in young Chinese adults: The mediating role of sleep

Environ Res. 2024 Feb 15:243:117765. doi: 10.1016/j.envres.2023.117765. Epub 2023 Nov 29.

Authors

Jialian Li¹, Jing Hou¹, Li Zhang¹, Siqi Dou¹, Liu Yang¹, Victor Teng², Chengshuai Zhang³, Hongwei Sun⁴, Peng Lu⁵, Yuming Guo⁶

Affiliations

¹ Binzhou Medical University, Yantai, Shandong, China.
² Climate, Air Quality Research Unit, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
³ ShengLi Oilfield Central Hospital, Dongying, Shandong, China.
⁴ Binzhou Medical University, Yantai, Shandong, China. Electronic address: sunhongwei@bzmc.edu.cn.
⁵ Binzhou Medical University, Yantai, Shandong, China. Electronic address: peng.lu@monash.edu.
⁶ Binzhou Medical University, Yantai, Shandong, China; Climate, Air Quality Research Unit, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia. Electronic address: yuming.guo@monash.edu.

PMID: 38036206
DOI: 10.1016/j.envres.2023.117765

Abstract

Objective: Existing evidence suggests that the natural environment can influence mental health. However, limited research has focused on the relationship between blue space and depressive symptoms in young adults. To investigate the association between blue space surroundings and depressive symptoms in young adults in China and explore the underlying mechanisms.

Methods: The study was conducted between September and November 2019, including 2,743 young adults from China. We assessed the exposure to blue space around participants' living environments during June, July, and August 2019 using the Modified Normalized Difference Water Index (MNDWI). Blue indexes were calculated for 300 m, 1000 m, and 3000 m circular buffer zones near residential environments. Logistic regression models were employed to explore the associations between blue space exposures (quartiles) and depressive symptoms, exploring potential mechanisms through structural equation modeling (SEM), while accounting for potential confounders. Stratification analysis was used to identify sensitive populations.

Results: Depressive symptoms were found in 148 (5.3%) of the 2,743 young adults in the study. We observed a negative correlation between depressive symptoms and average MNDWIs at participants' addresses (OR: 0.84; 95%CI: 0.72-0.98), within 300m (OR: 0.81; 95%CI: 0.70-0.95), 1000m (OR: 0.80; 95%CI: 0.69-0.93), and 3000m (OR:0.77; 95%CI: 0.66-0.89) buffer zones. Within the 1000m buffer zone, sleep was found to mediate 21% of the relationship between the presence of blue space and depressive symptoms. The stratified analysis revealed a stronger association between low MNDWI levels within the 1000m buffer zone and depressive symptoms in females (P < 0.05). Additionally, average MNDWI levels within the 3000m buffer zone were associated with depressive symptoms in both females and males.

Conclusions: Blue space could improve depressive symptoms, particularly in females, with sleep playing a mediating role. Incorporating blue spaces into environmental planning is important for improving mental health.

Keywords: Blue spaces; PHQ-9; Sleep; Young adults.

MeSH terms

China / epidemiology
Depression* / epidemiology
Environment*
Female
Humans
Male
Mental Health
Sleep
Young Adult