Children's Hospital Colorado

Circadian Rhythm Insulin Resistance: Linking Insufficient Sleep and Obesity

Breathing | November 30, 2018


For families

  • Obesity and type 2 diabetes are on the rise in adolescents
  • Poor sleep can contribute to insulin resistance, which occurs when insulin stops working and allows blood sugar to build up
  • Insulin resistance increases the risk for Type 2 diabetes

For health professionals

  • First known study of circadian timing of sleep and insulin sensitivity in obese adolescents
  • Longer sleep durations improved insulin sensitivity
  • Less than 6.6 hours of sleep led to increased insulin resistance

Research background: The connection between sleep health, circadian timing of sleep and insulin sensitivity in obese adolescents

More than 33 percent of adolescents in the U.S. are obese and are at risk for insulin resistance. Type 2 diabetes is on the rise for the population, and insulin resistance is a significant risk factor.

During puberty, insulin sensitivity decreases by about 50 percent, and more than half of obese teens experience more insulin resistance compared to their lean peers. In addition to the rise in obesity and effects of insulin sensitivity, adolescents commonly experience insufficient and delayed sleep.

Though the connection between poor sleep and insulin resistance has been demonstrated in adults, it has not been sufficiently studied in adolescents. Additionally, there has not yet been research on the connection between sleep health, circadian timing of sleep and insulin sensitivity in obese adolescents.

Lead author Stacey L. Simon, PhD, and other researchers at the Breathing Institute at Children's Hospital Colorado, sought to study the relationship between insulin resistance and sleep health in obese adolescents.

Research methods: measuring circadian rhythm and blood glucose in obese adolescents

Study participants

There were two cohorts:

  • APPLE cohort NCT02157974
  • CIRC cohort NCT02585830

Participants with diabetes, anemia or who were taking medications impacting insulin resistance or sleep were excluded from the study.

Study procedures

  • Participants wore actigraphy monitor for seven days at home prior to an outpatient study visit
    • Sleep monitored
    • Timed during school year
  • Researchers assessed insulin sensitivity by fasting labs and three-hour glucose tolerance tests
  • Participants were admitted to Children's Colorado's Clinical and Translational Research Center at 4 p.m. with dim light conditions, stayed until noon next day
    • Researchers obtained salivary and dim light melatonin samples every 30 to 60 minutes
    • Participants not exercise 72 hours before the study

Research results: study participants experienced insufficient sleep

Participants

Overall, participants experienced insufficient sleep on weekend and weekday nights, with an average 7.5 ± 0.88 hours and 6.6 ± 0.96 hours, compared to the recommended 8 to 10 hours.

Those with less than the median duration of sleep during the week had significantly wider phase angles between dim light melatonin offset and when they woke (p = 0.04), and shorter phase angles between dim light melatonin onset and when they woke (p = 0.02). This indicated a later circadian timing of sleep onset, compared to those who had more than the median sleep duration during the week.

Actigraphy and insulin sensitivity

There were several associations identified between measures from the actigraphy and insulin sensitivity. Researchers found that a longer total sleep time and more time in bed during the week and weekend, as well as an earlier weekday bedtime, were associated with better insulin sensitivity.

When comparing participants that slept less than 6.6 hours per night with those who slept at least 6.6 hours per night, researchers found that participants with more sleep had better insulin sensitivity. Also, participants with at least 6.6 hours of sleep had a lower insulin area under the curve.

Melatonin and insulin sensitivity

When analyzing melatonin and insulin sensitivity, shorter phase angles between weekday bedtime and dim light melatonin onset (indicating sleep onset at an earlier circadian time) were significantly associated with better insulin sensitivity.

Greater phase angles between bedtime during the week and dim light melatonin offset were also significantly associated with better insulin sensitivity and reflected longer sleep duration during the night.

Research discussion: Lack of sleep associated with insulin resistance in obese adolescents

Researchers found that the participants with more sleep and more time in bed in general, coupled with earlier bedtimes during the week, had better insulin sensitivity. Sleep at a later circadian time was associated with insulin resistance.

The school night sleep duration of study participants was approximately 1.5 hours less than the minimum recommended for adolescents. Short sleep duration was associated with impaired insulin sensitivity.

This is likely the first study to use an objective measurement of circadian rhythm with salivary melatonin assessment to research associations with insulin sensitivity in this population.

Researchers found significant differences in actigraphy variables between sleep on weekdays and weekends in the cohort. The cohort may have experienced a weekend phase delay or social jet lag (when sleep patterns are different on the weekends than they are during the week).

Insulin response measured by insulin area under the curve (but not glucose response) contributed to differences in insulin sensitivity. Researchers found a significantly greater insulin area under the curve for participants who slept less than 6.6 hours per night (but no difference in glucose area under the curve).

Research conclusion: Improving sleep and metabolic health in adolescents

Clinicians should consider assessing and treating obese adolescents for sleep and circadian health. Additional research is necessary to determine if sleep and circadian interventions, and possible later school start times, could improve metabolic health for this population.

Refer a patient

The Breathing Institute at Children's Colorado provides comprehensive clinical care and consultation for children with common and complex breathing problems.

Contact us: 720-777-6181
breathinginstitue@childrenscolorado.org

PRODWEBSERVER1