PROJECT SUMMARY/ABSTRACT
Over one in three Americans regularly sleep less than the recommended 7 hours per night. Alarmingly, adults who maintain
habitual short sleep durations (HSSD), such as medical and military personnel, emergency responders, shift workers, and
students, are alarmingly ~30% more likely to develop type 2 diabetes (T2D) versus adults who maintain adequate sleep
durations. Furthermore, data show that experimentally imposed sleep restriction lasting ~3 days to 2 weeks can impair
insulin sensitivity to levels commonly observed in people with pre-diabetes or in aging. However, it is not known if data
from rigidly controlled laboratory studies of experimental sleep restriction translates to people with real-world naturalistic
HSSD. Furthermore, neither the existing data from epidemiological nor laboratory-controlled studies inform mechanisms
or potential health benefits of interventions targeting HSSD. Molecular biomarkers that link risk of T2D with HSSD
could help overcome these knowledge gaps by: (1) identifying mechanisms underlying risk of T2D linked to real-
world HSSD and (2) informing whether sleep extension reverses such risk. Our preliminary data identified ceramides
as important candidate biomarkers that link risk of T2D with short sleep duration. Ceramides are central intermediate lipids
in sphingolipid metabolism and are particularly deleterious as they induce insulin resistance and are consistently
associated with incidence of cardiometabolic disease including T2D. Thus, our central hypothesis is that ceramides are
biomarkers that link risk of T2D with HSSD, and sleep extension is expected to lower plasma ceramides and improve
insulin sensitivity. To test our central hypothesis, we will conduct a randomized controlled trial with real-world sleep
extension in overweight and obese adults with HSSD. Participants will complete 1 week of baseline monitoring and then
be randomized to either sleep extension (target ≥8 hours of nightly time in bed) or HSSD maintenance for 8 weeks at home
(intervention segment). Following the baseline and intervention segments participants will complete rigorous overnight
laboratory visits to assess plasma ceramides (targeted metabolomics assay) and insulin sensitivity (hyperinsulinemic-
euglycemic clamp). Aim 1 will determine the impact of sleep extension on plasma ceramides and Aim 2 will determine
the impact of sleep extension on insulin sensitivity. Our expected findings will advance the field by identifying biomarkers
that link risk of T2D with HSSD and informing whether sleep extension reverses such risk. This knowledge could improve
our ability to quantify, track, and reduce an individual’s risk of T2D over time, which could be especially impactful for
people who are less successful with current diet and physical activity-based interventions. If effective, sleep extension would
therefore help improve quality of life and reduce the health and economic burdens of T2D on society.