Abstract MP70: Habitual Sleep Variability, Mediated by Energy Intake, is Associated with Abdominal Obesity in Adolescents

Abstract

Introduction: Although self-reported sleep duration has been associated with obesity, study of the association between objectively-measured habitual sleep pattern and the more metabolically relevant abdominal obesity, and the mediation factors for such an association, is limited. Hypothesis: We assessed the hypothesis that objectively-measured variability, mediated by excessive energy intake, is associated with abdominal obesity in adolescents. Methods: We used data from 421 adolescents in the Penn State Child Cohort follow-up examination. Actigraphy was used for 7 consecutive nights to calculate each participant’s mean sleep duration as habitual sleep duration (HSD) and the standard deviation of the mean as habitual sleep variability (HSV). Abdominal obesity was assessed by dual-energy x-ray absorptiometry as Android/Gynoid Fat Ratio and visceral fat area . Youth/Adolescents Food Frequency Questionnaire was used to obtain daily caloric, fat, carbohydrate, and protein intakes one year prior to the study. The R-based Mediation Effect Models were used to assess the association between sleep pattern and abdominal obesity, and quantitatively estimate the mediation effects of caloric intake and of other factors not analyzed in this report. Results: As shown in the table, after controlling for major confounders and BMI percentile, HSV was significantly and consistently associated with both abdominal obesity measures. The Mediation analysis consistently indicated a significant mediation effect of caloric intake, especially carbohydrate intake. For example, 20% of the association between HSV and visceral fat could be attributed to carbohydrate intake, while 80% by other factors not analyzed. HSD was not associated with abdominal obesity. Conclusions: Higher HSV, not HSD, is associated with abdominal obesity, which can be partially explained by increased caloric intake, especially from carbohydrate, in adolescents. More studies are needed to identify other mediation factors in the association.