Outdoor light at night, sleep disorder, and atopic diseases among children and adolescents: a cross-sectional study.

BACKGROUND: Limited evidence exists regarding the association between outdoor light at night (LAN) and atopic diseases in children and adolescents. We aim to identify the relationship of outdoor LAN exposure with atopic diseases in children and adolescents and to conduct an exploratory statistical mediation analysis involving sleep disorder. METHODS: This study collected data from 2012 to 2018 in China, recruiting 176,968 children and adolescents (6-18 years). LAN exposure was assessed using VIIRS/DNB data based on individual addresses. Atopic diseases were determined by self-reported doctor-diagnosed asthma, rhinitis, eczema and conjunctivitis during the past two years. We fitted generalized linear mixed-effects regression models to assess the association between LAN and atopic diseases and conducted mediation analysis to explore the role of sleep disorders in LAN exposure and atopic diseases. RESULTS: Higher quartiles of outdoor LAN were associated with higher odds of having atopic diseases (quartile 2, OR = 1.08 [95% CI: 1.05-1.12]; quartile 3, OR = 1.12 [95% CI: 1.08-1.16]; quartile 4, OR = 1.13 [95% CI: 1.08-1.17]) compared to quartile 1. Increased outdoor LAN exposure was also associated with increased odds for asthma, rhinitis, and eczema. Furthermore, greater ORs were found among children aged <12 years, boys, and higher per capita GDP. The proportion of the total association statistically explained by sleep disorder was 3.18% (95% CI: 0.27%-6.65%) for atopic diseases, 4.52% (95% CI: 0.23%-18.23%) for asthma, 2.38% (95% CI: 0.14%-4.88%) for rhinitis, and 4.07% (95% CI: 0.56%-14.88%) for eczema. CONCLUSION: Higher outdoor LAN was associated with higher odds of atopic diseases among school-aged children and adolescents. Exploratory analyses suggested a statistical contribution of sleep disorder to some of these associations.