Exposure to Artificial Light at Night in Adolescents and Subsequent Risk of Obesity in Young Adulthood: A Nationwide Population-Based Survey

Abstract

Abstract Background Previous studies have shown that artificial light at night (ALAN) is associated with obesity in adults or school-aged children, however, without addressing the critical transition period from adolescence to young adulthood. Methods In this study, we recruited incoming students from five geographically dispersed universities across China whose mean ALAN (nanowatts/cm2/sec) during adolescence was obtained using remotely observed nighttime data matched with information on their residence. Body weight and height were measured in a field survey. A mixed generalized linear model assessed the association between ALAN levels and body mass index (BMI). Results A total of 19,344 participants were included with a mean age and BMI of 18.3 ± 0.7 years and 21.2 ± 3.0 kg/m2, respectively. Our findings indicated a significant association between ALAN levels during the past 6 years and BMI (β = 0.1, 95% CI: 0.06–0.14, p < 0.0001). The results remained robust after multiple sensitivity analyses and adjustment for age, sex, parental educational, smoking, alcohol, and physical activity. In addition, a significant association between ALAN levels and BMI was observed in males (β = 0.23, 95% CI: 0.17–0.29, p < 0.0001) but not in females (β = 0.03, 95% CI: to0.08-0.02, p = 0.24). Conclusion These results reveal for the first time that ALAN exposure during adolescence is associated with subsequent increases in BMI at young adulthood. Further studies could help elucidate this association and clarify whether reducing exposure to ALAN during adolescence could contribute to obesity prevention in young adults.