The effect of exposure to artificial light at night (ALAN) on sleep disturbance: a systematic review and meta-analysis

🎖️ Top 10% JournalJan 7, 2026Environmental research

How Artificial Light at Night May Affect Sleep Problems: A Review and Analysis

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Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Participants with the highest exposure to artificial light at night (ALAN) had a 27% higher risk for sleep disturbance compared to those with low or no exposure.

A total of 15 studies involving 765,838 participants were reviewed to assess the impact of ALAN on sleep.
The meta-analysis included ten studies with 691,851 participants and found a pooled prevalence ratio of 1.27 for sleep disturbances.
Most studies indicated a high risk of bias, primarily due to challenges in exposure assessment.
Despite methodological limitations, there is a high certainty of evidence linking ALAN exposure to sleep disturbances.
Preventive measures, such as reducing nighttime lighting, may be necessary to mitigate these effects.

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BACKGROUND: Exposure to artificial light at night (ALAN) is an increasingly relevant environmental risk factor that can disrupt circadian rhythms and negatively affects organisms, including humans.

OBJECTIVES: This systematic review and meta-analysis of epidemiological observational studies aimed to examine the association between ALAN exposure and sleep disturbance in the general population.

METHODS: The protocol was published on PROSPERO (CRD42022335238). A comprehensive search in MEDLINE, Embase, PsycINFO and Web of Science was carried out. Title/abstract screening, full-text screening and risk of bias (RoB) assessment were conducted independently by two reviewers. Data were extracted by one and checked by another reviewer. Effect estimates were pooled using random-effects meta-analyses. A standardized transformation of effect measures into prevalence ratios (PR) was applied using VanderWeele's approach, since sleep-related outcomes are generally not rare. The certainty of evidence was judged using an adapted GRADE approach.

RESULTS: A total of 15 studies with 765,838 participants were included in this systematic review. A meta-analysis was conducted with ten studies (691,851 participants). Compared to participants with low or no ALAN exposure, those in the highest exposure group had a 27 % higher risk for sleep disturbance (Pooled PR: 1.27 [1.12; 1.45]). Most studies had a high RoB, mainly due to exposure assessment, but the certainty of the evidence was high.

CONCLUSION: This systematic review provides evidence of an association between ALAN exposure and sleep disturbance. However, current research is still limited by methodological challenges. Nevertheless, preventive measures are required, including reducing nighttime lighting and increasing public and policy awareness.

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