Obesity mediates the association of outdoor artificial light at night with type 2 diabetes mellitus

This study aims to explore the association of outdoor ALAN exposure with T2DM and the mediating effects of obesity in Chinese rural adults. A total of 38,108 participants were recruited from the Henan Rural Cohort. ALAN was positively associated with T2DM and FPG, and negatively associated with insulin, HOMA-IR, as well as HOMA-β, and the effect sizes of per-quartile increase in ALAN were 1.24(1.19, 1.28), 0.14(0.13, 0.16), -1.19(-1.24, -1.14), -0.22(-0.25, -0.20), and -27.30(-29.11, -25.48), respectively. The elderly, men, current smokers, individuals with lower education or income, or physical inactivity were more vulnerable to ALAN-related adverse health effects. The associations of ALAN with T2DM and glucose metabolism were mediated by WC, BMI, WHtR, WHR, VFI, and BFP, with estimated mediation proportions of 36.41%, 25.14%, 33.98%, 22.33%, 24.39%, and 25.85%, respectively, for T2DM. These findings emphasize the need for targeted public health interventions for reducing ALAN-related adverse health effects in rural areas.