0809 Insufficient and Late Sleep and Circadian Timing are Associated with Insulin Resistance in Adolescents with Obesity

Abstract

Introduction: Today's adolescents obtain well below the recommended 8-10 hours of sleep per night and have a tendency for delayed circadian timing. Insufficient and late sleep is associated with increased risk of obesity and lower insulin sensitivity (IS) in adults. However, little is known about the link between sleep duration, timing, and IS in adolescence. We hypothesized that short sleep duration and later sleep and circadian timing would be associated with IR in adolescents with obesity. Methods: Twenty-four participants with BMI >;85th percentile for age and sex completed the study during the academic school year (age 16.4 ± 1.0yrs, 62.5% female). Participants underwent one week of objective home sleep monitoring with wrist actigraphy and an oral glucose tolerance test to assess IS. Hourly-sampled overnight salivary melatonin was obtained in dim-light conditions in laboratory. Correlations between sleep and circadian variables with IS were examined. Results: Teens obtained insufficient sleep, particularly on school nights (M= 6.6h ±52.5min). Greater total sleep time on school nights was associated with better IS (r= 0.46, p< .05). Participants with school-night bedtimes before 11pm had significantly better IS compared to those with later bedtimes. A wider phase angle of entrainment between bedtime and melatonin offset was associated with better insulin sensitivity (r= 0.60, p< .01). Conclusion: These findings appear to confirm our hypothesis that insufficient sleep duration and later sleep and circadian timing are associated with reduced IS in this sample of obese adolescents during the school year and suggest that sleep disruption may be contributing to sharp increases in pediatric obesity and type 2 diabetes. Sleep should be evaluated as a component of healthy lifestyle intervention in obese adolescents.