Association between exposure to outdoor light at night and sleep habits in Shahedieh Cohort Study: A cross-sectional analysis

Sep 26, 2025Environmental pollution (Barking, Essex : 1987)

Outdoor light at night and its link to sleep patterns in the Shahedieh population

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Exposure to outdoor light at night ranged from 0.54 to 69.27 nanoWatts/cm2/sr among 8284 adults in Yazd province, Iran.

A significant association exists between outdoor light at night and shorter sleep duration, with an odds ratio of 1.21 per interquartile range increase.
Increased outdoor light at night is linked to higher use of sleep medications, with an odds ratio of 1.29.
Greater exposure to light at night is associated with lower odds of prolonged sleep latency.
Stronger associations were observed in women, non-employed individuals, and those who are overweight or obese.

AI simplified

Exposure to light at night (LAN) in residential environments has been suggested to be associated with a range of health outcomes, including sleep problems. Yet, the available evidence remains scarce. The study was based on data from 8284 adults (aged 35-70 years) residing in Yazd province, Iran, and participating in the Shahedieh Cohort Study enrolment phase (2015-2017). Sleep-related outcomes and covariates were collected through face-to-face interviews. Exposure to outdoor LAN (nanoWatts/cm2/sr) at different exposure windows was measured at residential addresses via satellite data. The association of LAN with sleep habits was tested using logistic regression models adjusted for relevant variables (reported as odds ratio [OR], and 95 % confidence intervals [CI], per interquartile range [IQR] increase of LAN). The outdoor LAN was in the range of 0.54-69.27 nanoWatts/cm2/sr (IQR: 14.91). A significant association was found between exposure to outdoor LAN and shorter sleep duration (OR: 1.21; 95 % CI: 1.10-1.32), and use of sleep medications (OR: 1.29; 95 % CI: 1.08-1.53). In contrast, greater LAN exposure was associated with lower odds for prolonged sleep latency. Associations were mostly stronger in women (e.g., use of sleep medications in men OR: 1.19; 95 % CI: 0.91-1.55 compared to women OR: 1.40; 95 % CI: 1.11-1.77), non-employed, and overweight/obese participants. Considering the large proportion of the exposed population in urban areas and the ongoing urbanization, outdoor LAN can be regarded as an increasing threat for public health.

Full Text

Full text is available at the source.

View full text (XML) ↗View full text ↗

Association between exposure to outdoor light at night and sleep habits in Shahedieh Cohort Study: A cross-sectional analysis

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief