163-LB: Youth with Delayed Sleep Phase Have Reduced Insulin Sensitivity

Abstract

Background: U.S. adolescents have short and delayed sleep, which may have metabolic consequences. We hypothesized that shorter sleep duration and later sleep phase are associated with decreased insulin sensitivity (SI) and worse glucose tolerance in overweight youth. Methods: We enrolled healthy youth aged 12-21y with BMI ≥80%ile (or ≥23kg/m2 if ≥18y). We obtained 14 days of wrist actigraphy (ActiGraph GT3XP-BTLE), a frequently-sampled 180 min OGTT (fsOGTT) with 10 samples, and administered validated questionnaires to estimate obstructive sleep apnea (OSA) risk. From actigraphy, we derived average sleep duration (SLD), mid-sleep time (MST), and sleep onset (SO). From the fsOGTT, we estimated SI using the OGTT Minimal Model and the disposition index (DI = SI x incremental insulin AUC 180min). We used multivariable linear regression to examine associations between sleep patterns and glycemic outcomes adjusting for confounders. Results: To date, we enrolled 24 youth (13F) with a median (IQR) age of 20.6y (19.2, 21.5), BMI of 25.2kg/m2 (24.3, 28.9), and fsOGTT glucoses of: fasting 91mg/dL (86, 95), 1h 141mg/dL (113, 179), and 2h 117mg/dL (78, 144). Participants had a median SLD of 7.3h (6.8, 8.1) per night, with SO of 1:13am (12:27am, 2:09am) and MST of 4:48am (4:23am, 6:01am). Age, race, and sex were not associated with sleep outcomes and not included in regressions. We found that (1) later MST [β=10.3, p=0.01] and SO [β=11.4, p=0.01] were each associated with higher fsOGTT 2h glucose, (2) later SO was associated with lower log-transformed SI [β= -0.27, p=0.04], and (3) later MST trended towards lower log-transformed DI [β= -0.1, p=0.055] adjusting for BMI and OSA risk. SLD was not related to any fsOGTT variables. Conclusions: To our knowledge, this is the first study in overweight youth to show that delayed sleep phase (SO and MST), but not short SLD, was associated with lower SI using the rigorous OGTT minimal model. Further studies are needed to examine if delayed sleep is a modifiable risk factor for diabetes prevention in youth. Disclosure T. A. Hitt: None. D. Stefanovski: None. A. Kelly: None. S. Malina: None. C. X. D. Wang: None. F. P. Sgambati: None. B. S. Zemel: None. J. Jun: None. S. N. Magge: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK115648); National Institutes of Health (UL1TR001878, UL1TR001079)