BMC public healthDec 13, 2025

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

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jun 28, 2026

Abstract

Essence

This meta-analysis links higher exposure to modestly higher risks of and overweight.

Evidence

A systematic review and random-effects meta-analysis of 13 observational studies involving 867,647 participants found higher LAN exposure was associated with obesity (OR 1.14, 95% CI 1.07-1.22) and overweight (OR 1.07, 95% CI 1.00-1.15), with stronger signals in North America and Asia than in Europe.

Caveat

The evidence is observational and highly heterogeneous (I² = 92.5% for both pooled outcomes), so the association should not be read as proof that LAN causes obesity or overweight.

Simplified

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 potentially elevating obesity risk, but evidence syntheses are outdated and limited.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.