Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children

Abstract Background Light at night (LAN) is found to be associated with elevated overweight and obesity in broad population. However, evidence for the long-term LAN exposure trajectories and its influence to weight gain remained limited, especially to school-aged children who experience critical phy...

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Main Authors: Xijie Wang, Manman Chen, Din Son Tan, Jie Hu, Bin Dong, Yu Jiang, Wannian Liang
Format: Article
Language:English
Published: BMC 2025-07-01
Series:BMC Medicine
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Online Access:https://doi.org/10.1186/s12916-025-04262-0
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author Xijie Wang
Manman Chen
Din Son Tan
Jie Hu
Bin Dong
Yu Jiang
Wannian Liang
author_facet Xijie Wang
Manman Chen
Din Son Tan
Jie Hu
Bin Dong
Yu Jiang
Wannian Liang
author_sort Xijie Wang
collection DOAJ
description Abstract Background Light at night (LAN) is found to be associated with elevated overweight and obesity in broad population. However, evidence for the long-term LAN exposure trajectories and its influence to weight gain remained limited, especially to school-aged children who experience critical physical development. We aimed to analyze variations in body weight among children with different LAN exposure profiles, and how varying levels of LAN exposure influenced children’s overweight (including obesity) risk overt time. Methods Children who had ≥ 5 school health examinations between 2005 and 2020 in Zhongshan were recruited in this population-based longitudinal study. LAN data of each child at each survey year were modeled with group-based trajectory model and named as sharp rise (reference; 5.5%), mild rise, high stable (69.7%), and decline. Differences of overweight incidence between groups were analyzed. Results Among 218,283 children (1,318,542 measurements; 53.1% boys; baseline mean [SE] age, 9.1 [2.5]), 12,050 (5.5%) were categorized in the sharp rise group and 152,030 (69.7%) in the stable high group. In the 189,011 participants categorized as normal or underweight at baseline, the overall incidence of overweight during follow-up was 8.80/1000 person-years (95% CI: 8.69, 8.91). Compared to the sharp rise group, the hazard ratios (HR) for developing overweight were 1.67 (95% CI: 1.28, 2.18) for boys and 1.56 (95% CI: 1.21, 2.01) for girls in stable high group, followed by the mild rise group. The HRs in decline group were non-significant. Overall, the stable high trajectory of LAN exposure accounted for 40.24% (range: 22.14, 54.14) of overweight risk in boys and 36.09% (range: 17.79, 50.31) in girls, while the mild rise group contributed approximately 23% to the overall risk. Conclusions Higher LAN exposure trajectories, especially at early school age, had persistent effect to overweight and obesity risk in school-aged children. Interventions to reduce LAN exposure during school age may help reduce excessive weight gain in children.
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spelling doaj-art-a5f36e19e88d4730b1f399126912b36c2025-08-20T03:46:09ZengBMCBMC Medicine1741-70152025-07-0123111010.1186/s12916-025-04262-0Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese childrenXijie Wang0Manman Chen1Din Son Tan2Jie Hu3Bin Dong4Yu Jiang5Wannian Liang6Vanke School of Public Health, Tsinghua UniversitySchool of Population Medicine and Public Health, Chinese Academy of Medical Sciences and Peking Union Medical CollegeVanke School of Public Health, Tsinghua UniversitySchool of Pharmacy and Medical Sciences, Griffith University, Nathan CampusInstitute of Child and Adolescent Health & School of Public Health, Peking UniversitySchool of Health Policy and Management, Chinese Academy of Medical Sciences and Peking Union Medical CollegeVanke School of Public Health, Tsinghua UniversityAbstract Background Light at night (LAN) is found to be associated with elevated overweight and obesity in broad population. However, evidence for the long-term LAN exposure trajectories and its influence to weight gain remained limited, especially to school-aged children who experience critical physical development. We aimed to analyze variations in body weight among children with different LAN exposure profiles, and how varying levels of LAN exposure influenced children’s overweight (including obesity) risk overt time. Methods Children who had ≥ 5 school health examinations between 2005 and 2020 in Zhongshan were recruited in this population-based longitudinal study. LAN data of each child at each survey year were modeled with group-based trajectory model and named as sharp rise (reference; 5.5%), mild rise, high stable (69.7%), and decline. Differences of overweight incidence between groups were analyzed. Results Among 218,283 children (1,318,542 measurements; 53.1% boys; baseline mean [SE] age, 9.1 [2.5]), 12,050 (5.5%) were categorized in the sharp rise group and 152,030 (69.7%) in the stable high group. In the 189,011 participants categorized as normal or underweight at baseline, the overall incidence of overweight during follow-up was 8.80/1000 person-years (95% CI: 8.69, 8.91). Compared to the sharp rise group, the hazard ratios (HR) for developing overweight were 1.67 (95% CI: 1.28, 2.18) for boys and 1.56 (95% CI: 1.21, 2.01) for girls in stable high group, followed by the mild rise group. The HRs in decline group were non-significant. Overall, the stable high trajectory of LAN exposure accounted for 40.24% (range: 22.14, 54.14) of overweight risk in boys and 36.09% (range: 17.79, 50.31) in girls, while the mild rise group contributed approximately 23% to the overall risk. Conclusions Higher LAN exposure trajectories, especially at early school age, had persistent effect to overweight and obesity risk in school-aged children. Interventions to reduce LAN exposure during school age may help reduce excessive weight gain in children.https://doi.org/10.1186/s12916-025-04262-0Artificial light at nightAdolescent healthOverweight and obesityLongitudinal studyGroup-based trajectory study
spellingShingle Xijie Wang
Manman Chen
Din Son Tan
Jie Hu
Bin Dong
Yu Jiang
Wannian Liang
Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
BMC Medicine
Artificial light at night
Adolescent health
Overweight and obesity
Longitudinal study
Group-based trajectory study
title Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
title_full Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
title_fullStr Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
title_full_unstemmed Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
title_short Trajectories of night light exposure and risk of overweight and obesity: a 15-year longitudinal cohort study of 218,239 Chinese children
title_sort trajectories of night light exposure and risk of overweight and obesity a 15 year longitudinal cohort study of 218 239 chinese children
topic Artificial light at night
Adolescent health
Overweight and obesity
Longitudinal study
Group-based trajectory study
url https://doi.org/10.1186/s12916-025-04262-0
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