Outdoor light at night, overweight, and obesity in school-aged children and adolescents

Li-Zi Lin; Xiao-Wen Zeng; Badhan Deb; Maya Tabet; Shu-Li Xu; Qi-Zhen Wu; Yang Zhou; Hui-Min Ma; Duo-Hong Chen; Gong-Bo Chen; Hong-Yao Yu; Bo-Yi Yang; Qiang Hu; Yun-Jiang Yu; Guang-Hui Dong; Li-Wen Hu

doi:10.1016/j.envpol.2022.119306

Outdoor light at night, overweight, and obesity in school-aged children and adolescents

Environ Pollut. 2022 Jul 15:305:119306. doi: 10.1016/j.envpol.2022.119306. Epub 2022 Apr 14.

Authors

Li-Zi Lin¹, Xiao-Wen Zeng¹, Badhan Deb¹, Maya Tabet², Shu-Li Xu¹, Qi-Zhen Wu¹, Yang Zhou³, Hui-Min Ma⁴, Duo-Hong Chen⁵, Gong-Bo Chen¹, Hong-Yao Yu¹, Bo-Yi Yang¹, Qiang Hu⁶, Yun-Jiang Yu³, Guang-Hui Dong¹, Li-Wen Hu⁷

Affiliations

¹ Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment, Department of Occupational and Environmental Health, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China.
² Department of Epidemiology and Biostatistics, College for Public Health & Social Justice, Saint Louis University, Saint Louis, MO, 63104, USA.
³ State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, 510655, China.
⁴ State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
⁵ Department of Air Quality Forecasting and Early Warning, Guangdong Environmental Monitoring Center, State Environmental Protection Key Laboratory of Regional Air Quality Monitoring, Guangdong Environmental Protection Key Laboratory of Atmospheric Secondary Pollution, Guangzhou, 510308, China.
⁶ Department of Pediatric Surgery, Weifang People's Hospital, Weifang, 261041, China.
⁷ Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment, Department of Occupational and Environmental Health, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: huliwen@mail.sysu.edu.cn.

PMID: 35430310
DOI: 10.1016/j.envpol.2022.119306

Abstract

Previous studies have indicated that outdoor light at night (LAN) is associated with a higher prevalence of overweight or obesity in adults. However, the association of LAN levels with overweight or obesity in children is still unknown. This study utilized data from the Seven Northeastern Cities study, which included 47,990 school-aged children and adolescents (ages 6-18 years). Outdoor LAN levels were measured using satellite imaging data. Weight and height were used to calculate age-sex-specific body mass index (BMI) Z-scores based on the World Health Organization (WHO) growth standards. Overweight status and obesity were defined using the Chinese standard. Information regarding socioeconomic status, sleep-related characteristics, and obesogenic factors were obtained using a questionnaire. A generalized linear mixed model examined the associations of outdoor LAN levels (in quartiles) with the outcomes of interest. Compared to children in the lowest quartile of outdoor LAN levels, children exposed to higher outdoor LAN levels had larger BMI Z-scores and higher odds of being overweight (including obesity) or obese, with the largest estimates in the third quartile [BMI Z-score: β = 0.26, 95% CI: 0.18-0.33; overweight (including obesity): OR = 1.40, 95% CI: 1.25-1.56; obesity: OR = 1.46, 95% CI: 1.29-1.65]. There was a significant sex difference (P_interaction<0.001) in the association of outdoor LAN levels with BMI Z-scores, and the association was stronger in males. Results remained robust following multiple sensitivity analyses and the adjustment of sleep-related characteristics, obesogenic factors, and environmental exposures. Our findings suggest that higher outdoor LAN levels are associated with larger BMI Z-scores and greater odds of overweight (including obesity) and obesity in school-aged children and adolescents. Further, the association between outdoor LAN levels and BMI Z-scores is stronger in males. Future studies with exposure assessments that consider both outdoor and indoor LAN exposures are needed.

Keywords: Chilhood obesity; Light exposure; Public health.

MeSH terms

Adolescent
Body Mass Index
Child
China / epidemiology
Female
Humans
Light Pollution
Lighting*
Male
Overweight* / epidemiology
Pediatric Obesity* / epidemiology
Schools
Sleep