卧室夜间光暴露延迟大学生昼夜节律时相

Exposure to real-ambient bedroom light at night delayed circadian rhythm in healthy Chinese young adults: A cross-sectional study

暴露于真实环境卧室夜间光延迟健康中国青年的昼夜节律：一项横断面研究

Authors: Yu-xiang Xu, Yan Huang, Wen-qin Ding, Yi Zhou, Yu-ting Shen, Yu-hui Wan, Pu-yu Su, Fang-biao Tao, Ying Sun

Source: Environmental Research. 2024 Mar 21; 251(Pt 2): 118657.

DOI: 10.1016/j.envres.2024.118657

Graphical Abstract

Abstract

Background: Light at night (LAN) have attracted increased research attention on account of its widespread health hazards. However, the underlying mechanism remains unknown. The objective of this study was to investigate the effects of real-ambient bedroom LAN exposure on circadian rhythm among young adults and potential sex differences.

Methods: Bedroom LAN exposure was measured at 60-s intervals for 2 consecutive days using a portable illuminance meter. Circadian phase was determined by the dim light melatonin onset (DLMO) time in 7 time-series saliva samples.

Results: The mean age of the 142 participants was 20.7 ± 0.8 years, and 59.9% were women. The average DLMO time was 21:00 ± 1:11 h, with men (21:19 ± 1:12 h) later than women (20:48 ± 1:07 h). Higher level of LAN intensity (LAN_avg ≥ 3lx vs. LAN_avg < 3lx) was associated with an 81.0-min later in DLMO time (95% CI: 0.99, 1.72), and longer duration of nighttime light intensity ≥ 5lx (LAN5; LAN5 ≥ 45 min vs. LAN5 < 45 min) was associated with a 51.6-min later in DLMO time (95% CI: 0.46, 1.26). In addition, the delayed effect of LAN exposure on circadian phase was more pronounced in men than in women (all P-values < 0.05).

Conclusions: Overall, bedroom LAN exposure was significantly associated with delayed circadian rhythm. Additionally, the delayed effect is more significant in men. Keeping bedroom dark at night may be a practicable option to prevent circadian disruption and associated health implications. Future studies with more advanced light measurement instrument and consensus methodology for DLMO assessment are warranted.

摘要

背景：夜间光暴露（light at night，LAN）由于其广泛的健康危害而引起越来越多的关注。然而，其潜在机制尚不清楚。本研究的目的是调查真实环境下卧室LAN暴露对青年大学生昼夜节律的影响及潜在性别差异。

方法：使用便携式照度计，以60秒为间隔连续测量2天卧室LAN暴露。通过7个唾液样本的暗光环境褪黑素开始分泌（dim light melatonin onset，DLMO）时间来确定昼夜节律时相。

结果：142名参与者的平均年龄为20.7 ± 0.8岁，女性占59.9%。平均DLMO时间为21:00 ± 1:11 h，男性（21:19 ± 1:12 h）晚于女性（20:48 ± 1:07 h）。较高水平的LAN暴露（LAN_avg ≥3lx vs.LAN_avg <3lx）与DLMO时间延迟81.0 min相关（95%CI：0.99，1.72），夜间光照强度 ≥5lx持续时长较长（LAN5 ≥ 45min vs. LAN5 <45min）与DLMO时间延迟51.6 min相关（95%CI：0.46，1.26）。此外，LAN暴露对昼夜节律的延迟效应在男性中比在女性中更加显著（所有P值均< 0.05）。

结论：总之，卧室LAN暴露与昼夜节律时相延迟显著相关。此外，延迟效应在男性中更为显著。晚上保持卧室黑暗可能是一种切实可行的选择，以防止昼夜节律紊乱及相关的健康影响。未来有必要使用更先进的光测量仪器和一致的DLMO评估方法进行研究。