Outdoor light at night, genetic predisposition and type 2 diabetes mellitus: A prospective cohort study

Zhihu Xu; Jianbo Jin; Teng Yang; Yuxin Wang; Jing Huang; Xiaochuan Pan; Kelly Frank; Guoxing Li

doi:10.1016/j.envres.2022.115157

Outdoor light at night, genetic predisposition and type 2 diabetes mellitus: A prospective cohort study

Environ Res. 2023 Feb 15:219:115157. doi: 10.1016/j.envres.2022.115157. Epub 2022 Dec 23.

Authors

Zhihu Xu¹, Jianbo Jin¹, Teng Yang¹, Yuxin Wang¹, Jing Huang¹, Xiaochuan Pan¹, Kelly Frank², Guoxing Li³

Affiliations

¹ Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing, 100191, Beijing, China.
² Environmental Research Group,School of Public Health,Imperial College London, London, United Kingdom.
³ Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, 38 Xueyuan Road, Haidian District, Beijing, 100191, Beijing, China. Electronic address: liguoxing@bjmu.edu.cn.

PMID: 36572333
DOI: 10.1016/j.envres.2022.115157

Abstract

Background: According to animal and human epidemiologic studies, exposure to outdoor light at night (LAN) may cause circadian disruption, which may disturb sleep quality and lead to incident type 2 diabetes mellitus (T2DM).

Methods: We followed 283,374 persons from 2006 through 2020. Outdoor LAN exposure was estimated using satellite data for individual address with 500 m² scale buffer during follow-up. Incidence of T2DM was confirmed by hospital inpatient records. We identified potential confounders by a directed acyclic graph, including demographic, genetic, individual and regional level socioeconomic status, and environmental risk factors, and calculated hazard ratios (HRs) and 95% confidence intervals (CIs) through time-varying Cox proportional hazard model. Furthermore, we examined the association of outdoor LAN with a defined health sleep scores and moderation of genetic predisposition and shift work on the relationship of outdoor LAN and incident T2DM.

Results: We identified 7,775 incident T2DM cases over 3,027,505 person-years. Higher outdoor LAN exposures were significantly associated with higher risk of T2DM. The estimated HR for incident T2DM with an interquartile range (IQR: 11.22 nW/cm²/sr) increase in outdoor LAN was 1.05 (95%CI: 1.01, 1.09) in the fully adjusted model. Participants who lived in the highest quarter of outdoor LAN area were more likely to develop T2DM (HR: 1.14,95%CI: 1.02, 1.27). Besides, those who were exposed to higher levels of outdoor LAN had poorer sleep quality. No moderation role of PRS on outdoor LAN-induced T2DM observed both on the multiplicated and additive scale. The hazards of outdoor LAN were observed in those who never owned a night shift work.

Conclusion: Although further work is required to clarify potential mechanisms, our findings indicate that exposure to residential outdoor LAN may contribute to T2DM risk and low sleep quality.

Keywords: Cohort study; Genetic predisposition; Outdoor light at night; Shift work; Sleep quality; T2DM.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Diabetes Mellitus, Type 2* / etiology
Diabetes Mellitus, Type 2* / genetics
Genetic Predisposition to Disease
Humans
Light
Prospective Studies
Risk Factors
Sleep Initiation and Maintenance Disorders*

Grants and funding

MC_PC_17228/MRC_/Medical Research Council/United Kingdom