Association between outdoor artificial light at night and sleep duration among older adults in China: A cross-sectional study

Kejia Hu; Wanlu Li; Yunquan Zhang; Huashuai Chen; Chen Bai; Zhenchun Yang; Thiess Lorenz; Keyang Liu; Kokoro Shirai; Jinglu Song; Qi Zhao; Yali Zhao; Junfeng Jim Zhang; Jing Wei; Jiahao Pan; Jin Qi; Tingting Ye; Yi Zeng; Yao Yao

doi:10.1016/j.envres.2022.113343

Association between outdoor artificial light at night and sleep duration among older adults in China: A cross-sectional study

Environ Res. 2022 Sep;212(Pt B):113343. doi: 10.1016/j.envres.2022.113343. Epub 2022 Apr 21.

Authors

Kejia Hu¹, Wanlu Li¹, Yunquan Zhang², Huashuai Chen³, Chen Bai⁴, Zhenchun Yang⁵, Thiess Lorenz⁶, Keyang Liu⁷, Kokoro Shirai⁷, Jinglu Song⁸, Qi Zhao⁹, Yali Zhao¹⁰, Junfeng Jim Zhang⁵, Jing Wei¹¹, Jiahao Pan¹, Jin Qi¹, Tingting Ye¹², Yi Zeng¹³, Yao Yao¹⁴

Affiliations

¹ Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, 310058, China.
² School of Public Health, Wuhan University of Science and Technology, Wuhan, 430065, China.
³ Business School of Xiangtan University, Xiangtan, 411105, China.
⁴ School of Labor and Human Resources, Renmin University of China, Beijing, 100872, China.
⁵ Global Health Institute and the Nicholas School of Environment, Duke University, Durham, 27708, USA.
⁶ Department of Cardiology, University Heart and Vascular Center Hamburg, Hamburg, 20246, Germany.
⁷ Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita Shi, Osaka, 565-0871, Japan.
⁸ Department of Urban Planning and Design, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China.
⁹ Department of Epidemiology, School of Public Health, Shandong University, Jinan, 250012, China.
¹⁰ Central Laboratory, Hainan Hospital of Chinese People's Liberation Army General Hospital, Sanya, 572000, China.
¹¹ Department of Atmospheric and Oceanic Science, Earth System Science Interdisciplinary Center, University of Maryland, College Park, 20742, USA.
¹² School of Public Health and Preventive Medicine, Monash University, Melbourne, 3004, Australia.
¹³ Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, 100871, China. Electronic address: zengyi@nsd.pku.edu.cn.
¹⁴ China Center for Health Development Studies, Peking University, Beijing, 100191, China. Electronic address: yao.yao@bjmu.edu.cn.

PMID: 35461841
DOI: 10.1016/j.envres.2022.113343

Abstract

Background: Light after dusk disrupts the circadian rhythms and shifts the timing of sleep later; but it is unknown whether outdoor artificial light at night (ALAN) affects sleep quality. This study aimed to explore the association between residential outdoor ALAN and sleep duration in a nationally representative sample of Chinese older adults.

Methods: We examined the cross-sectional associations of outdoor ALAN with self-reported sleep duration in 13,474 older adults participating in the 2017-2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Outdoor ALAN exposure was estimated at the residence level using satellite images. We applied generalized linear mixed models to investigate the association between ALAN exposure and sleep duration. We performed stratified analyses by age, sex, education, and household income levels. Moreover, we used multi-level logistic regression models to investigate the effects of ALAN on the short sleep duration (≤6 h) and the long sleep duration (>8 h), respectively, in reference to sleep for >6-8 h per day.

Results: We found a significant association between outdoor ALAN intensity and sleep duration. The highest quartile of ALAN was associated with 17.04 (95% CI: 9.42-24.78) fewer minutes of sleep as compared to the lowest quartile. The reductions in sleep duration per quartile change in ALAN were greater in the young old (≥65-85 years) and in those with higher levels of education, and those with higher household income, respectively. We did not detect a sex difference. In addition, those in the highest quartile of ALAN were more likely to report a 25% (95% CI: 10%-42%) increase in short sleep (<6 h), and a 21% (95% CI: 9%-31%) decrease in long sleep (>8 h).

Conclusions: Increasing outdoor nighttime light intensity surrounding residences was associated with shorter sleep duration in older residents in China. This finding implies the importance of urban outdoor artificial light management as a potential means to lower the public health burden of sleep disorders.

Keywords: ALAN; China; Nighttime light; Outdoor light; Sleep; Sleep duration.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
China / epidemiology
Circadian Rhythm
Cross-Sectional Studies
Female
Humans
Light
Light Pollution*
Male
Sleep
Sleep Wake Disorders*