Indoor and outdoor artificial light-at-night (ALAN) and cancer risk: A systematic review and meta-analysis of multiple cancer sites with a critical appraisal of exposure assessment

Authors: Palomar-Cros A, Deprato A, Papantoniou K, Straif K, Lacy P, Maidstone R, Adan A, Haldar P, Moitra S, Navarro JF, Durrington H, Moitra S, Kogevinas M, Harding BN

Year: 2024

Category: Epidemiology

Journal: Science of The Total Environment

DOI: 10.1016/j.scitotenv.2024.177059

URL: https://www.sciencedirect.com/science/article/pii/S0048969724072164

Abstract

Overview

Exposure to artificial light-at-night (ALAN) has been linked to cancer risk. This systematic review and meta-analysis seeks to expand the understanding beyond previous studies that primarily focused on breast cancer.

Methodology

Six databases, two registries, and Google Scholar were searched for relevant studies until April 17, 2024, considering observational studies including cohort, case-control, and cross-sectional studies on indoor and outdoor ALAN exposure. Quality was evaluated using the Joanna Briggs Institute tools.

Findings

28 studies with 2,508,807 individuals were included for qualitative synthesis.
Meta-analysis shows higher risks of breast cancer associated with outdoor ALAN (meta-estimate = 1.12, CI: 1.03–1.23).
A non-significant positive association found between indoor ALAN levels and breast cancer risk.
A non-statistically significant increased risk of prostate cancer for higher levels of outdoor ALAN was observed.
Qualitative synthesis suggests positive associations with other cancers such as non-Hodgkin lymphoma and colorectal cancer.

Conclusion

Strong associations between outdoor ALAN and breast cancer were noted. However, limitations due to low resolution of satellite imagery used in most studies were highlighted. Future work should enhance exposure assessments and extend analyses to other cancer types.

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