Sleep problems mediate the association between outdoor light pollution and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria

M Helbich; A Burov; D Dimitrova; I Markevych; M Nieuwenhuijsen; A Dzhambov

doi:10.1016/j.envres.2024.119897

Sleep problems mediate the association between outdoor light pollution and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria

M Helbich^*, A Burov, D Dimitrova, I Markevych, M Nieuwenhuijsen, A Dzhambov

^*Corresponding author for this work

Urban Accessibility and Social Inclusion

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Background: Nighttime light is a growing anthropogenic health threat, particularly in urban areas. Limited evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with people's mental health by disrupting sleep-wake cycles. Aims: We assessed 1) the association between ALAN exposure and adults’ symptoms of depression and anxiety, 2) whether the association was modified by sex, age, and income, and 3) the mediating role of sleep problems. Methods: We obtained cross-sectional data from 4,068 adults from the five largest Bulgarian cities. Depression and anxiety symptoms were measured using the 4-item Patient Health Questionnaire (PHQ-4). Sleep problems were self-reported based on three items. Outdoor ALAN at residential addresses was assessed using annual radiance levels obtained from satellite imagery. Regression models were adjusted for person-level characteristics, green space, and nitrogen dioxide (NO₂). We also assessed effect modification by sex, age, and income. Using mediation analyses, we tested sleep problems as a mediator of the ALAN-PHQ-4 association. Results: Greater ALAN exposure in the fully adjusted model was marginally associated with higher PHQ-4 scores. We observed no effect modification. The mediator, sleep problems, was also positively associated with ALAN. The mediation of sleep problems was significantly positive. While the direct association was null, the total ALAN association was marginally and positively associated with PHQ-4 scores. Conclusions: Our findings suggest a positive association between outdoor nighttime light pollution and mental health. Poor sleep quality is a possible pathway relating ALAN exposure to mental health. Considering the increasing ubiquity and intensity of urban nighttime illumination, light pollution-reducing policies may provide significant health benefits for urban populations.

Original language	English
Article number	119897
Journal	Environmental Research
Volume	263
Early online date	31 Aug 2024
DOIs	https://doi.org/10.1016/j.envres.2024.119897
Publication status	Published - 15 Dec 2024

Bibliographical note

Publisher Copyright:
© 2024 The Authors

Funding

The research leading to this work was supported by the \u201CStrategic research and innovation program for the development of Medical University \u2013 Plovdiv\u201D No. BG-RRP-2.004-0007-C01, Establishment of a network of research higher schools, National plan for recovery and resilience, financed by the European Union \u2013 NextGenerationEU. The funder did not influence the study design, data collection and analysis, interpretation, or article drafting. All authors had data access. The first and last authors were responsible for submitting the article for publication.

Funders	Funder number
European Commission
Medical University	BG-RRP-2.004-0007-C01

Keywords

Air pollution
Anxiety
Depression
Eastern Europe
Green space
Insomnia
Light at night
Mental health

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.envres.2024.119897Licence: CC BY

1-s2.0-S0013935124018024-mainFinal published version, 1.73 MBLicence: CC BY

Cite this

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title = "Sleep problems mediate the association between outdoor light pollution and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria",

abstract = "Background: Nighttime light is a growing anthropogenic health threat, particularly in urban areas. Limited evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with people's mental health by disrupting sleep-wake cycles. Aims: We assessed 1) the association between ALAN exposure and adults{\textquoteright} symptoms of depression and anxiety, 2) whether the association was modified by sex, age, and income, and 3) the mediating role of sleep problems. Methods: We obtained cross-sectional data from 4,068 adults from the five largest Bulgarian cities. Depression and anxiety symptoms were measured using the 4-item Patient Health Questionnaire (PHQ-4). Sleep problems were self-reported based on three items. Outdoor ALAN at residential addresses was assessed using annual radiance levels obtained from satellite imagery. Regression models were adjusted for person-level characteristics, green space, and nitrogen dioxide (NO2). We also assessed effect modification by sex, age, and income. Using mediation analyses, we tested sleep problems as a mediator of the ALAN-PHQ-4 association. Results: Greater ALAN exposure in the fully adjusted model was marginally associated with higher PHQ-4 scores. We observed no effect modification. The mediator, sleep problems, was also positively associated with ALAN. The mediation of sleep problems was significantly positive. While the direct association was null, the total ALAN association was marginally and positively associated with PHQ-4 scores. Conclusions: Our findings suggest a positive association between outdoor nighttime light pollution and mental health. Poor sleep quality is a possible pathway relating ALAN exposure to mental health. Considering the increasing ubiquity and intensity of urban nighttime illumination, light pollution-reducing policies may provide significant health benefits for urban populations.",

keywords = "Air pollution, Anxiety, Depression, Eastern Europe, Green space, Insomnia, Light at night, Mental health",

author = "M Helbich and A Burov and D Dimitrova and I Markevych and M Nieuwenhuijsen and A Dzhambov",

note = "Publisher Copyright: {\textcopyright} 2024 The Authors",

year = "2024",

month = dec,

day = "15",

doi = "10.1016/j.envres.2024.119897",

language = "English",

volume = "263",

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T1 - Sleep problems mediate the association between outdoor light pollution and symptoms of depression and anxiety

T2 - A cross-sectional, multi-city study in Bulgaria

AU - Helbich, M

AU - Burov, A

AU - Dimitrova, D

AU - Markevych, I

AU - Nieuwenhuijsen, M

AU - Dzhambov, A

PY - 2024/12/15

Y1 - 2024/12/15

N2 - Background: Nighttime light is a growing anthropogenic health threat, particularly in urban areas. Limited evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with people's mental health by disrupting sleep-wake cycles. Aims: We assessed 1) the association between ALAN exposure and adults’ symptoms of depression and anxiety, 2) whether the association was modified by sex, age, and income, and 3) the mediating role of sleep problems. Methods: We obtained cross-sectional data from 4,068 adults from the five largest Bulgarian cities. Depression and anxiety symptoms were measured using the 4-item Patient Health Questionnaire (PHQ-4). Sleep problems were self-reported based on three items. Outdoor ALAN at residential addresses was assessed using annual radiance levels obtained from satellite imagery. Regression models were adjusted for person-level characteristics, green space, and nitrogen dioxide (NO2). We also assessed effect modification by sex, age, and income. Using mediation analyses, we tested sleep problems as a mediator of the ALAN-PHQ-4 association. Results: Greater ALAN exposure in the fully adjusted model was marginally associated with higher PHQ-4 scores. We observed no effect modification. The mediator, sleep problems, was also positively associated with ALAN. The mediation of sleep problems was significantly positive. While the direct association was null, the total ALAN association was marginally and positively associated with PHQ-4 scores. Conclusions: Our findings suggest a positive association between outdoor nighttime light pollution and mental health. Poor sleep quality is a possible pathway relating ALAN exposure to mental health. Considering the increasing ubiquity and intensity of urban nighttime illumination, light pollution-reducing policies may provide significant health benefits for urban populations.

AB - Background: Nighttime light is a growing anthropogenic health threat, particularly in urban areas. Limited evidence suggests that exposure to outdoor artificial light at night (ALAN) may be associated with people's mental health by disrupting sleep-wake cycles. Aims: We assessed 1) the association between ALAN exposure and adults’ symptoms of depression and anxiety, 2) whether the association was modified by sex, age, and income, and 3) the mediating role of sleep problems. Methods: We obtained cross-sectional data from 4,068 adults from the five largest Bulgarian cities. Depression and anxiety symptoms were measured using the 4-item Patient Health Questionnaire (PHQ-4). Sleep problems were self-reported based on three items. Outdoor ALAN at residential addresses was assessed using annual radiance levels obtained from satellite imagery. Regression models were adjusted for person-level characteristics, green space, and nitrogen dioxide (NO2). We also assessed effect modification by sex, age, and income. Using mediation analyses, we tested sleep problems as a mediator of the ALAN-PHQ-4 association. Results: Greater ALAN exposure in the fully adjusted model was marginally associated with higher PHQ-4 scores. We observed no effect modification. The mediator, sleep problems, was also positively associated with ALAN. The mediation of sleep problems was significantly positive. While the direct association was null, the total ALAN association was marginally and positively associated with PHQ-4 scores. Conclusions: Our findings suggest a positive association between outdoor nighttime light pollution and mental health. Poor sleep quality is a possible pathway relating ALAN exposure to mental health. Considering the increasing ubiquity and intensity of urban nighttime illumination, light pollution-reducing policies may provide significant health benefits for urban populations.

KW - Air pollution

KW - Anxiety

KW - Depression

KW - Eastern Europe

KW - Green space

KW - Insomnia

KW - Light at night

KW - Mental health

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DO - 10.1016/j.envres.2024.119897

M3 - Article

SN - 0013-9351

VL - 263

JO - Environmental Research

JF - Environmental Research

M1 - 119897

ER -

Sleep problems mediate the association between outdoor light pollution and symptoms of depression and anxiety: A cross-sectional, multi-city study in Bulgaria

Abstract

Bibliographical note

Funding

Keywords

UN SDGs

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