Abstract Introduction Insufficient sleep, fragmented sleep, disrupted slow wave sleep are all associated with risk for diabetes. Conventional sleep staging methods of analyzing polysomnography do not fully encompass the depth of sleep. The odds ratio product (ORP) is a continuous measurement of sleep depth, but it is unknown if ORP is linked to insulin sensitivity. Thus, we assessed ORP and insulin sensitivity in healthy young adults with habitual insufficient sleep, hypothesizing deeper sleep will be linked to better insulin sensitivity. Methods We analyzed data from 16 participants (9 female; aged 21.1±3.5yr; BMI 21.4±2.1kg/m2 mean±SD) with habitual sleep 6.5h per night. Participants completed 2-weeks of ambulatory monitoring with actigraphy. Following at home monitoring participants underwent overnight polysomnography to calculate ORP, a QEEG derived measure of sleep depth (ranging from 0 deeply asleep to 2.5 fully awake), and completed the Pittsburgh Sleep Quality Index (PSQI) survey to assess subjective sleep quality. Oral Glucose Tolerance Testing (OGTT) was completed to calculate Matsuda Index (MI) insulin sensitivity. Results Average PSQI was 5.1±2.4 (mean±SD), TST was 5.48±0.9h, ORP during the total recording time was 0.79±0.23, and MI was 7.6±4.4. Linear regression indicated both lower ORP and shorter TST were individually associated with worse MI (all p 0.05). Yet, when included together in the model, neither were significant. Additionally, shorter TST was associated p 0.05) with lower ORP. Conclusion Participants exhibited insufficient sleep indicated by short TST and average PSQI 5. As expected, shorter TST was associated with worse MI, indicating higher diabetes risk. Interestingly, shorter TST also associated with lower ORP, suggesting deeper sleep possibly driven by greater homeostatic sleep pressure. However, deeper sleep indicated, by ORP, was also associated with worse MI in this context of adults with habitual insufficient sleep, counter to our hypothesis. These preliminary analyses suggest among adults with insufficient sleep, deeper sleep depth may not confer metabolic benefit. Future analyses will compare ORP to MI among adults with 7h sleep/night to clarify whether the ORP–insulin sensitivity relationship differs under conditions of habitual adequate sleep. Support (if any) NIH-UM1TR004409; NIH-K01HL145099; NIH-T32DK110966; NIH-R01HL166733; University of Utah Seed Grant-10060570; University of Utah Diabetes and Metabolism Research Center Graduate Student Fellowship
Stegman et al. (Fri,) studied this question.