Impact of artificial light at night on obesity and overweight: a systematic review and meta-analysis

Dec 13, 2025BMC public health

Artificial light at night linked to higher risk of overweight and obesity: a review and combined analysis

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Abstract

A 14% increased risk of was observed in individuals with the highest exposure to compared to those with the lowest exposure.

The analysis included 13 studies with 867,647 participants, showing a significant association between artificial light at night (LAN) exposure and obesity.
A 7% increase in the risk of being overweight was also noted with higher LAN exposure.
The strongest obesity association was found in North America, with an odds ratio of 1.21, while a significant association was also observed in Asia.
Both adults and adolescents exhibited significant associations with obesity risk related to LAN exposure, without notable differences between sexes.
All included studies were rated high quality, with sensitivity analyses confirming the findings and no evidence of publication bias.

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BACKGROUND: Global rates are rising sharply, prompting interest in environmental drivers beyond diet and activity. Widespread disrupts circadian rhythms and metabolism. potentially elevating obesity risk, but evidence syntheses are outdated and limited.

METHODS: We conducted a systematic search of databases including PubMed, EMbase, Cochrane Library, and Web of Science. Eligible observational studies (cohort or cross-sectional) were required to report adjusted risk estimates (odds ratio [OR], relative risk [RR], or hazard ratio [HR] with 95% confidence intervals [95% CI]) for obesity or overweight, with quantifiable LAN exposure. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS) for cohort studies and the AHRQ criteria for cross-sectional studies. A random-effects model was applied for effect size pooling, alongside subgroup analyses stratified by geographic region, age, and sex, supported by sensitivity analyses and Egger's test for publication bias assessment.

RESULTS: Our analysis included 13 studies involving 867,647 participants (9 cross-sectional and 4 cohort studies). A significant 14% increased risk of obesity was observed in the highest LAN exposure group compared to the lowest (OR = 1.14, 95% CI: 1.07-1.22; I² = 92.5%, P < 0.001). For overweight risk, a 7% increase was noted (OR = 1.07, 95% CI: 1.00-1.15; I² = 92.5%, P < 0.001). Regionally, the strongest association was in North America (OR = 1.21, 95% CI: 1.10-1.32; I² = 46.6%, P = 0.132) and significant in Asia (OR = 1.14, 95% CI: 1.06-1.21; I² = 85.5%, P < 0.001), but not in Europe. Age-wise, both adults (OR = 1.16) and adolescents (OR = 1.17) exhibited significant associations (P < 0.05), with no notable differences between sexes. All studies were deemed high quality (mean NOS score: 7.50; mean AHRQ score: 7.56), and sensitivity analyses confirmed the findings with no evidence of publication bias (P > 0.05).

CONCLUSIONS: Exposure to LAN significantly correlates with increased obesity and overweight risks, influenced by geographic and age-specific factors. These results highlight LAN as a noteworthy environmental risk factor for metabolic health, advocating for informed public health strategies, including region-specific lighting regulations and "screen curfews" for adolescents.

Key numbers

1.14

Increase in Risk

Odds ratio for in highest exposure group vs. lowest

1.07

Increase in Overweight Risk

Odds ratio for overweight in highest exposure group vs. lowest

867,647

Total Participants

Number of participants across all included studies

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Impact of artificial light at night on obesity and overweight: a systematic review and meta-analysis

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