Personal 24-hour light exposure pattern with obesity and adiposity-related parameters in school-aged children: A...

The 24-h light exposure pattern is an essential feature of circadian rhythms and a potential contributor to body fat health. However, no previous studies have investigated 24-h light exposure patterns in relation to adiposity-related parameters in children. This cross-sectional study recruited school-aged children in Chuzhou, Anhui province, China. Personal 24-h light exposure was collected for 5 days and was divided into four measures: light at daytime (LAD)≥100 lx and <100 lx; light at night (LAN)≥1 lx and <1 lx. Adiposity-related parameters were measured via a body composition analyzer. The association of light exposure with adiposity-related parameters was analyzed using compositional data analysis (CoDA). This study included 831 children 8.53 ± 0.62 years, who were exposed to LAD≥100 lx for 490.1 ± 92.7 min and LAN≥1 lx for 311.2 ± 98.5 min. The proportion of time spent in LAD≥100 lx increasing by 1 % (14.4 min/day) was linked to a decline of 3.10 % in percentage of body fat (PBF). In contrast, prolonged exposure to LAN≥1 lx by 14.4 min/day was associated with an increase of 3.49 % in PBF (All P < 0.01). These associations were robust in boys after gender stratification. CoDA estimated that reducing the time of LAN≥1 lx had more influence in decreasing the odds of childhood overweight/obesity than increasing the time of LAD≥100 lx. Suboptimal 24-h light exposure patterns (brighter nights, darker days) play a threatening role in childhood overweight/obesity. Bright LAN replaced with darker LAN or bright LAD might help decrease the odds of childhood overweight/obesity.