Higher overall pre-sleep artificial light at night intensity is associated with shorter total sleep time in shift-working nurses and daytime office workers
This observational study of 136 shift nurses and 66 daytime office workers found that higher overall pre-sleep light intensity (Light PC1) measured by wrist actigraphy was strongly associated with shorter total sleep time (β=-0.59, SE=0.08, p<0.001). Bedroom light intensity showed a weaker but significant association with shorter total sleep time (β=-0.21, SE=0.09, p=0.028). Temporal patterns of light exposure (Light PC2) were not significantly associated with any sleep outcomes.
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Higher overall pre-sleep artificial light at night intensity is associated with shorter total sleep time in shift-working nurses and daytime office workers The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 34/100 (low).
The Claim
Higher overall pre-sleep artificial light at night intensity is associated with shorter total sleep time in shift-working nurses and daytime office workers
This conclusion is most relevant to: Hong Kong shift-working nurses (n=136) and daytime office workers (n=66).
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Principal component analysis of pre-sleep artificial light at night exposure patterns and the associations with sleep disturbances in Hong Kong shift-working nurses and daytime office workers. (Occupational and environmental medicine, 2026) —
How It Works
The proposed biological pathway:
- ▸Pre-sleep light exposure suppresses melatonin secretion
- ▸Melatonin suppression delays circadian rhythm
- ▸Delayed circadian rhythm shortens sleep duration
- ▸Result: Shorter total sleep time
Who Might Benefit
Evidence fit by population:
- ▸Hong Kong shift-working nurses (n=136) and daytime office workers (n=66)
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Observational study design, cannot establish causality
- ▸Actigraphy-based light measurement may not fully capture all light properties (e.g., wavelength, spectrum)
- ▸Potential residual confounding from sociodemographic and work-related factors
Frequently Asked Questions
What is the main finding of this study?▼
Higher overall pre-sleep light intensity is associated with shorter total sleep time, with a stronger effect for wrist-worn light than bedroom light.
Does the temporal pattern of light exposure matter?▼
No, the temporal pattern (Light PC2) was not significantly associated with any sleep outcomes in this study.
Who were the participants?▼
The study included 136 shift-working nurses and 66 daytime office workers in Hong Kong, with data collected from July 2022 to February 2023.
What sleep parameters were measured?▼
Total sleep time, sleep onset latency, wake after sleep onset, and sleep timing were measured using actigraphy.
References
- 1.Li B, Liu Y, Li W, Ma JYT, Huss A, Chan J, Wing YK, Tse LA. “Principal component analysis of pre-sleep artificial light at night exposure patterns and the associations with sleep disturbances in Hong Kong shift-working nurses and daytime office workers..” Occupational and environmental medicine, 2026. PMID: 42532831 DOI: 10.1136/oemed-2026-111078