Delayed Sleep in Youth Associated with Increased Insulin Secretion

Introduction and Objective: Delayed sleep phase has been shown to adversely affect adult insulin regulation. It is not known whether this phenomenon applies to adolescents and young adults (AYA), who typically adopt delayed sleep phase in normal development. To test this hypothesis, we performed a secondary analysis of an observational study of metabolic risk in overweight South Asian (SA), White (W), and African American (AA) AYA (CHAriSmA). Methods: A subset of participants from the CHAriSmA study underwent actigraphy visceral fat area (VF) by DXA and quantification of insulin regulation by 180-min OGTT (insulin sensitivity by the Minimal Model, first-pass hepatic extraction by the insulin clearance model, and insulin secretory rate (ISR) (total, dynamic and static) by the β-cell function model, disposition index (DI) calculated: Si x ISR AUC). We examined the association between average mid-sleep time (MST) with insulin outcomes (transformed for normalization) using linear regression adjusted for sex and VF in the combined cohort. As a secondary outcome, we examined outcomes stratified by ancestry. Results: The cohort was comprised of 74 AYA [11 SA, 30 AA, 33 W; 51% F, BMI 26.3 kg/m2 (24.3, 30.1)]. VF was lower in AA vs W (p=0.04) and vs SA (p=0.009) [SA: 102cm2 (95.2,121), AA: 74.9cm2(53.9,97.7), W: 91.0cm2(66.1,114)]. MST was earlier in W vs SA (p=0.04) [Avg. SA: 5:49am, AA: 4:41am, W: 4:31am]. Later MST was associated with higher total AUC ISR (p=0.006) and static AUC ISR (0.004). The other insulin parameters (including DI) were not associated with MST. In stratified analysis, the W group exhibited the MST-insulin relationships (ISR: p=0.002, static ISR: p=0.002, Si p=0.017), which was not detected in other ancestry groups. Conclusion: In overweight AYA, later MST was associated with greater compensatory insulin secretion, primarily during the static phase of the OGTT. Ancestry-specific findings will need to be confirmed in a larger study, but may highlight the need to consider whether genetic and socio-cultural factors may also impact diurnal rhythm and insulin dynamics. Disclosure: T. Hitt: None. D. Stefanovski: None. C. Wang: None. S. Malina: None. F. Sgambati: None. B.S. Zemel: Consultant; Current; Incyte. Consultant; Ended; Regeneron Pharmaceuticals Inc. A. Kelly: None. J. Jun: Research Support; Current; Ketone IQ. Advisory Panel; Ended; ApniMed. S.N. Magge: None. Funding: NIH NDDK R01DK115648; CTSA: CHOP: UL1TR001878, Hopkins: UL1TR001079