Luminous threats: The health impacts of artificial nighttime light on metabolic and mental health: A scoping review

Introduction: Artificial light at night (ALAN) has been increasingly recognized as a potential disruptor of human health, affecting both metabolic and mental well-being. Growing evidence links ALAN exposure to conditions such as obesity, hypertension, type 2 diabetes mellitus (T2DM) and depression. Objective: To conduct a scoping review of the available scientific literature up to September 2024, focusing on the impact of ALAN on metabolic and mental health outcomes. The review also aims to identify existing gaps in the research and provide recommendations for future studies and public health interventions. Material and Methods: This review included studies from databases such as PubMed, Google Scholar, and Scopus. The inclusion criteria encompassed publications presenting empirical data and clinical trials in English and Spanish that assessed ALAN exposure and health outcomes. Results: A total of 32 studies were reviewed, with a combined sample size exceeding 1.6 million participants. Study designs varied and included large-scale cohort studies, cross-sectional analyses, and randomized clinical trials. Associations between ALAN exposure and metabolic disorders (n = 14), hypertension (n = 6), T2DM (n = 5), and mental health disorders (n = 7) were identified. Findings consistently suggest that ALAN contributes to chronodisruption, impacting metabolic and psychological health. Conclusions: ALAN is a significant environmental factor contributing to adverse health outcomes, particularly metabolic disorders and mental health disturbances. While findings suggest actionable interventions, further longitudinal studies are required to confirm causality and explore preventative strategies.