Systematic review and meta-analyses of the relationship between short sleep and incidence of obesity and effectiveness of sleep interventions on weight gain in preschool children.

The aim of this study is to determine (a) whether short sleep is associated with the incidence of obesity and (b) whether interventions beneficial for sleep reduce weight gain in preschool children. We systematically searched PubMed, Embase, Web of Science and Cochrane up to 12/09/2019. (a) Studies that were included were prospective, had follow-up ≥1 year, with sleep duration at baseline and required outcome measures. (b) Intervention trials with sleep intervention and measures of overweight or obesity were included. Data were extracted according to PRISMA guidelines. (a) The risk of developing overweight/obesity was greater in short sleeping children (13 studies, 42 878 participants, RR: 1.54; 95% CI, 1.33 to 1.77; p < 0.001). Sleep duration was associated with a significant change in BMI z-score (10 studies, 11 cohorts and 29 553 participants) (mean difference: -0.02 unit per hour sleep; -0.03 to -0.01; p < 0.001). (b) Four of the five intervention studies reported improved outcomes: for BMI (-0.27 kg/m ; -0.50 to -0.03; p = 0.03); for BMI z-score (-0.07 unit; -0.12 to -0.02; p = 0.006). Short sleep duration is a risk factor or marker of the development of obesity in preschool children. Intervention studies suggest that improved sleep may be beneficially associated with a reduced weight gain in these children.