Outdoor light at night is a modifiable environmental factor for metabolic syndrome: The 33 Communities Chinese Health Study (33CCHS)

• Published in: The Science of the total environment Vol. 954; p. 176203
• Main Authors: Hu, Li-Wen, Gong, Yan-Chen, Zou, Hong-Xing, Wang, Le-Bing, Sun, Yanan, Godinez, Alejandro, Yang, Han-Yu, Wu, Si-Han, Zhang, Shuo, Huang, Wen-Zhong, Gui, Zhao-Huan, Lin, Li-Zi, Zeng, Xiao-Wen, Yang, Bo-Yi, Liu, Ru-Qing, Chen, Gongbo, Li, Shanshan, Guo, Yuming, Dong, Guang-Hui
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2024
• Subjects: Blood pressure; Fasting blood glucose; Light at night; Metabolic syndrome; Triglycerides; Waist circumference; Waist circumference; Light at night; Blood pressure; Triglycerides; Fasting blood glucose; Metabolic syndrome
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.176203

Metabolic syndrome (MetS) is a significant public health problem and presents an escalating clinical challenge globally. To combat this problem effectively, urgent measures including identify some modifiable environmental factors are necessary. Outdoor artificial light at night (LAN) exposure garnered much attention due to its impact on circadian rhythms and metabolic process. However, epidemiological evidence on the association between outdoor LAN exposure and MetS remains limited. To determine the relationship between outdoor LAN exposure and MetS, 15,477 adults participated the 33 Communities Chinese Health Study (33CCHS) in 2009 were evaluated. Annual levels of outdoor LAN exposure at participants' residential addresses were assessed using satellite data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Generalized linear mixed effect models were utilized to assess the association of LAN exposure with MetS and its components, including elevated waist circumference (WC), triglycerides (TG), blood pressure (BP), fasting blood glucose (FBG), and reduced high-density lipoprotein cholesterol (HDL-C). Effect modification by various social demographic and behavior factors was also examined. Overall, 4701 (30.37 %) participants were defined as MetS. The LAN exposure ranged from 6.03 to 175.00 nW/cm2/sr. The adjusted odds ratio (OR) of MetS each quartile increment of LAN exposure were 1.43 (95 % CI: 1.21–1.69), 1.44 (95 % CI: 1.19–1.74) and 1.52 (95 % CI: 1.11–2.08), respectively from Q2–Q4. Similar adverse associations were also found for the components of MetS, especially for elevated BP, TG and FBG. Interaction analyses indicated that the above associations were stronger in participants without habitual exercise compared with those with habitual exercise (e.g. OR were 1.52 [95 % CI: 1.28–1.82] vs. 1.27 [95 % CI, 1.04–1.55], P-interaction = 0.042 for MetS). These findings suggest that long-term exposure to LAN can have a significant deleterious effect on MetS, potentially making LAN an important modifiable environmental factor to target in future preventive strategies. [Display omitted] •We studied 15,477 Chinese adults in a cross-sectional study.•Outdoor light at night was positively related to the odds of MetS and its components.•Outdoor light at night and MetS associations were stronger without habitual exercise.•Outdoor light at night is a modifiable environmental factor in prevention strategies.