0251 Sex differences in the associations of childhood obesity with sleep characteristics, access to screens, and nocturnal melatonin

Abstract

Abstract Introduction Insufficient sleep and circadian rhythm alterations are associated with metabolic disorders including obesity, with increasing evidence that these associations can emerge in childhood. In parallel, screen media access in the bedroom at night has negative effects on circadian rhythms, sleep, and other behaviors, which can contribute to obesity development. In the current work, we analyzed the associations of childhood obesity with self-reported sleep characteristics, access to screens in the bedroom, and nocturnal melatonin, considering potential sex differences. Methods The study cohort is composed of 244 children 7-16 years old, among which 140 have a body mass index z-scores >2, characterized as obesity according to world health organization criteria. There are 124 girls (11.21 ± 2.42 years) and 120 boys (11.19 ± 2.22 years). Melatonin was measured through immunoassay in saliva samples, which were collected at three time points of the evening of a school day: 4h before sleep, 2h before sleep, and 1h after sleep start. The chronotype score was obtained using the Horne and Ostberg questionnaire. Participants reported the number of screens present in the bedroom at night, and their bedtimes and wakeup times during both weekdays and weekend. The sleep disturbance scale for children and an abbreviated pediatric sleep questionnaire about sleep apnea symptoms were completed by a parent. Results BMI z-scores were significantly correlated with more parent-reported sleep disturbances (p< 0.01), higher sleep apnea scores (p< 0.01), shorter sleep duration during weekdays (p< 0.01), and the number of screens in the bedroom (p=0.05) in boys but not in girls (p=0.52, p=0.15, p=0.83, and p=0.37). On the other hand, BMI z-scores were significantly correlated with melatonin level at +1h after sleep onset (p=0.05) in girls but not in boys (p=0.96). No significant correlations were observed between the BMI z-score and the pre-sleep melatonin measures. Conclusion According to our findings, there is some differentiation by sex in relationships between body weight and various sleep and circadian measures. Specifically, in boys, obesity was associated with shorter and disturbed sleep with more sleep apnea, whereas in girls, obesity was linked with lowered nocturnal melatonin expression. Support (if any)