Sleep and insulin sensitivity in adolescents at risk of type 2 diabetes: the Sleep Manipulation in Adolescents at Risk of Type 2 Diabetes (SMART2D)randomized crossover study

STUDY OBJECTIVES

To investigate the effect of increasing sleep duration for 1 week, compared to a week of habitual and decreased sleep, on insulin sensitivity(IS) in adolescents at risk for type 2 diabetes(T2D).

METHODS

Adolescents, 13-18y old, at risk for T2D, with obesity and other risk factors, were recruited for a randomized(1:1), open-label, sex-stratified crossover study, that manipulated time-in-bed to modify sleep duration (measured by actigraphy). Following a week of habitual(HB) sleep, time-in-bed was increased(IN) and decreased(DE) by 1h30min/night for 1 week, counterbalanced across participants(HBINDE or HBDEIN), and separated by a week of washout sleep. The main outcome measure was IS, obtained via 2-h oral-glucose-tolerance-test conducted after each sleep week.

RESULTS

Of the 43 participants recruited, 36(84%) completed all sleep interventions (52.8% female, age=15.1y, body-mass-index=99.9th percentile, order: HBINDE=18 and HBDEIN=18). On average, during the HB week, participants slept 7h31min/night; sleep duration was 1h02min/night higher during the IN week and 1h19min/night lower during the DE week. We found a significant effect of sleep week on IS with a large effect size. Following the IN sleep week, IS was 20% higher compared to after the HB and DE sleep weeks, but there was no significant difference in IS following HB versus DE sleep weeks.

CONCLUSION

Whenever possible, clinicians should empower youth at risk of T2D to improve their sleep duration, since even a modest increase in sleep duration of 1h/night for one-week can have a positive impact on IS in this population.

Influence of sleep on developing brain functions and structures in children and adolescents: A systematic review

This systematic review examined the associations between sleep and brain functions and structures in children and adolescents aged 1-17 ys. Included studies (n = 24) were peer-reviewed and met the a priori determined population (apparently healthy children and adolescents aged 1 y to 17 ys), intervention/exposure/comparator (various sleep characteristics including duration, architecture, quality, timing), and outcome criteria (brain functions and/or brain structures, excluding cognitive function outcomes). Collectively, the reviewed studies report some relationships between inadequate sleep and resultant differences in brain functions or structures. Although the research presented supports and offers more insight into the importance of sleep for the developing brain of children and adolescents, no firm conclusions that apply broadly may be drawn from these results, particularly because of the diversity of the sleep variables and outcomes. However, it is clear that sleeping habits in the pediatric population should be prioritized. Health care providers should continue to recommend healthy sleep practices and adequate time for sleep, as they are essential for overall health, including brain health.