Year: 2011
Type: article
Abstract: The authors have indicated no financial conflicts of interest. Explanations for the rampant rise in childhood obesity abound. While debate over its various causes continues, sleep researchers have made considerable progress towards understanding the association between chronic short sleep duration and obesity. As such, the Institute of Medicine (IOM) recently codified the promotion of age-appropriate sleep durations as a primary goal in the prevention of childhood obesity.1 In this issue of SLEEP, Silva and colleagues2 provide additional support for this recommendation with a longitudinal investigation of school-age children's sleep duration and a range of developmental outcomes (i.e., obesity, anxiety/depression, and learning problems). Their primary finding strengthens the growing body of evidence that short sleep duration among children is associated with weight gain over time.3,4 Silva et al.2 also find marginally significant (P < 0.10) associations between short sleep duration and both anxiety/depression and learning problems. Although these latter trends may not have reached conventional levels of statistical significance likely as a result of limited statistical power given the study's sample size (i.e., 304 observations), they should not be ignored. Despite varied study samples, measurement techniques, and methods of statistical adjustment, nearly all existing studies of sleep duration and weight gain in children have reached the same conclusion—short sleep duration is associated with subsequent weight gain. The study by Silva et al.2 improves upon preceding longitudinal studies by using objectively measured polysomnographic data. Of the nine previously published longitudinal studies of which we are aware, eight used parent-reported data,3,5 and one—the most recent—used accelerometry6 to measure sleep duration. Silva et al.'s2 use of polysomnography, an accurate measure of physiological sleep, thus represents a clear advance in the science. The consistency of results across epidemiologic studies is further undergirded by evidence from laboratory studies indicating that sleep deprivation has adverse effects on glucose and appetite regulation,7 thus providing putative physiological mechanisms linking sleep duration and obesity. Given the near uniformity of the scientific evidence further bolstered by the report of Silva et al., we believe it is time to move from science to practice: We recommend translating these recent findings directly into large-scale prevention efforts. Consistent with the recent recommendation by the IOM, obesity prevention interventions should incorporate sleep hygiene education. This education would help parents and children adapt children's bedtime behaviors to facilitate adequate sleep quality and quantity by reducing arousal and promoting relaxation at bedtime (e.g., by eliminating evening television and video games). It will be important to educate parents, who play a crucial role in defining and enforcing bedtimes and bedtime routines, about age-appropriate sleep needs. Prior research indicates that over two-thirds of adolescents with parentally set bedtimes actually use them8; following a consistent bedtime is associated with increased sleep duration, increased daytime wakefulness, and reduced depression and fatigue.8,9 It may also make sense to add sleep hygiene components to early childhood care and education interventions, including home visiting and child care programs.10 A challenge ahead is to create a sleep hygiene intervention that maximizes the potential developmental benefits of achieving age-appropriate sleep. To date, evaluations of existing programs have been disappointing. One randomized trial of an intervention for infants showed no weight-related effects at five-year follow-up.11 Furthermore, even the highest quality intervention might be hampered by contextual factors outside a parent's or child's control. These include the conduciveness of household and neighborhood environments to promoting sound sleep; school start times; and a host of other sociodemographic and household characteristics.12–14 As such, educating children and parents about sleep hygiene may not adequately alter sleep quality or quantity if the root causes of sleep disturbance consist of circumstances such as crowded living conditions, inadequate air conditioning or heat, hunger, family discord, and financial insecurity. From a social disparities perspective, efforts should be made to improve the sleep of the most disadvantaged children, in particular, since these children are most vulnerable for a range of adverse developmental outcomes.15 Thus, in addition to incorporating sleep hygiene into obesity prevention campaigns, attention should be given to fundamentally improving children's living conditions and the quality of their home environments, which may produce benefits in terms of both sleep and obesity. Doing so will require a better understanding of what aspects of households and neighborhoods lead to suboptimal sleep. Studies on the relationship between sleep and child development still have important limitations. Given that many of these studies are observational in nature, they risk omitted variable bias and reverse causation. For example, one important confounding factor omitted from many studies is children's use of electronic media (television, internet), which may lead to poor sleep, increased sedentary activity, and subsequent weight gain. In addition, some parents may do a better job of monitoring both their children's sleep habits and their eating habits in ways that have not been adequately measured in research protocols, but may drive associations between childhood sleep and obesity. Further, the extent to which the association between sleep and weight gain is driven by sleep quantity, as opposed to sleep quality, is unclear. There are also unresolved questions about sleep duration thresholds and how they relate to various aspects of child development. For example, what is the optimal sleep duration for preventing unhealthy weight gain? How might the optimal sleep duration differ by age group? Does it differ for specific developmental outcomes? Does it vary by physical activity level or sleep quality? Are there adverse effects of too much sleep for children (as has been found for adults)? And, how might individual variation in sleep need matter? These questions have important implications for better understanding potential causal links between sleep duration and child well-being. They can be examined in the context of testing whether real-world sleep-related interventions reduce obesity and other adverse developmental outcomes for children. Obesity prevention programs primarily focus on achieving a well-balanced diet and regular physical exercise for good reason as these are key ingredients for attaining and maintaining a healthy body weight. However, Silva et al.,2 building on a growing body of evidence, make a compelling case that short sleep duration also plays a vital role in unhealthy weight gain during childhood, and potentially a host of other suboptimal outcomes. The public health costs of childhood obesity and chronic sleep deficiency are substantial. We should therefore work to produce effective sleep education interventions and encourage efforts by parents, schools, and policy makers to prioritize our children's sleep.
Source: SLEEP
DOI: 10.5665/sleep.1226
Authors: Lauren Hale, Lawrence M. Berger
Language: English
Topic: Sleep and related disorders
Subfield: Experimental and Cognitive Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: bronze
OpenAlex ID: W2094688297