Measurement and Analysis of Exposure to Light at Night in Epidemiology

Artificial light at night (ALAN) has become an increasingly important topic in epidemiology, as numerous studies have established a relationship between ALAN and adverse health effects, including cancer, obesity, depression, and sleep disruption. ALAN exposure measurements, however, vary from study to study and each measurement method has strengths and weaknesses. We review and summarize the pros and cons of different methods that have been used to quantify the light exposure in epidemiological settings, which include widely used remote sensing data, interview data, and individual-level wearable and handheld equipment. We also summarize the methodological approaches that have been used to analyze the spatial distribution of ALAN, as well as the relationships between ALAN and various adverse health outcomes. Finally, we highlight emerging technologies that could be used to measure the ALAN exposure for epidemiological studies, and how spatial analytical methods, such as geographically weighted regression and spatial autoregressive models can be leveraged to understand the spatial and temporal characteristics of ALAN and its mechanisms in regulating human physiology and behavior.