Short sleep duration linked to diabetes risk factors in early life
Shorter sleep duration appears to be associated with higher body mass index (BMI) and insulin resistance among children, and this relationship is independent of adiposity and observed across ethnicities, according to a study.
In a cohort of multiethnic children aged 9 to 10 years in UK who slept an average of 10.5 per night (95 percent CI, 8 to 12) on school days, significant inverse graded associations were observed between sleep duration, adiposity and diabetes risk markers (insulin, insulin resistance and glucose). [Pediatrics 2017;doi: 10.1542/peds.2017-0338]
Multilevel linear regression models showed that increasing the mean sleep duration by an hour could reduce BMI by 0.19 (–0.28 to –0.09; p<0.0001), fat mass index by 0.03 kg/m5 (–0.05 to 0.00; p=0.03), homeostasis model assessment insulin resistance by 2.9 percent (–4.4 to –1.2) and fasting glucose by 0.24 percent (–0.44 to –0.03).
Sleep duration was not associated with HbA1c or cardiovascular risk, and observed associations with insulin and glucose persisted despite further adjustment for adiposity markers.
The cohort comprised 4,525 children, and those who had longer hours of sleep were on average shorter and had lower body weight, fat-free mass, fat mass index levels and skinfold thickness. Sleep duration differed slightly by ethnicity, with white European children having the longest mean sleep duration and black African-Caribbean children having the shortest.
Sleep time was calculated from self-reported usual time of going to bed and getting up on a school day. Levels of serum lipids and insulin, plasma glucose and HbA1c were measured from fasting blood samples.
The investigators pointed out that the favourable effect of an extra hour of sleep on diabetes risk factors should be considered in relation to the largest observed ethnic difference in BMI and insulin resistance within the study population, such that children of South Asian origin had 30 percent higher insulin resistance and 0.4 lower BMI compared with children of white European descent.
“If experimental evidence were to corroborate the associations observed between sleep duration and type 2 diabetes precursors … reducing levels [of such precursors] even by modest amounts in childhood may have longer-term implications for reduced diabetes in later life,” the investigators said, noting that insulin resistance levels in early life may affect diabetes risk over a 10-year period and that greater weight gain trajectories in childhood increase the risk of adolescent nonalcoholic fatty liver disease (a well-accepted precursor to diabetes), the investigators said. [Arch Pediatr Adolesc Med 2010;164:53–60; J Hepatol 2014;61:626–632]
In an editorial piece, Drs Nicole Glaser and Dennis Styne from the University of California Davis highlighted the importance of the current findings as they “confirm that the relationship between sleep, obesity and the metabolic syndrome is unlikely to simply reflect lifestyle variables (eg, activity level, screen time or parental vigilance) and instead reflect more complex relationships that must be explored.” [Pediatrics 2017;doi:10.1542/peds.2017-2015]
Data from the present study provide ideal information on which to base a future large clinical trial, which is key to resolving “the question of whether relationships between sleep, obesity and the metabolic syndrome are causal or associated via related but independent pathways,” Drs Glaser and Styne added.