A letter to the editor in defense of sleep recommendations

Individual Differences in Optimum Sleep for Daily Mood During Adolescence

Efforts to establish an empirical basis for recommended sleep durations during adolescence need to take into account individual differences in optimum sleep, defined as the amount of sleep at which peak functioning is observed. A total of 419 adolescents (Mage = 15.03 years) with Mexican American backgrounds reported their nightly sleep duration and daily mood for a 2-week period at 1 or 2 waves of data collection, 1 year apart. Adolescents also completed an established measure of symptomatology. Multilevel modeling revealed a nonlinear association between sleep duration and next-day mood, whereby both too little and too much sleep were associated with elevated levels of daily distress. Significant individual differences in optimum sleep were observed such that younger adolescents and those with elevated levels of internalizing and total symptomatology evidenced greater sleep durations on nights before they reported their lowest levels of daily distress. Younger adolescents and those with higher internalizing and total symptomatology may need more sleep to reach their peak functioning the next day, at least in terms of daily mood.

Sleep duration, quality of life and depression in adolescents: a school-based survey

BACKGROUND

The main objective of this study was to assess the link between sleep duration, quality of life and depression in adolescents. The secondary objective was to study the sleeping behavior of a large sample of adolescents from different socioeconomic backgrounds.

METHODS

Study subjects were high school students studying in or around Paris with a general, vocational or technological training background. A survey was conducted to evaluate the subject's perception of their own sleep, quality of life and depression.

RESULTS

The survey analyzed 855 students between 14 and 19 years of age, with equal numbers of males and females. The average sleep duration was 7 h 14 min ±1 h 20 min and was inversely correlated with age (r=-0.142, P<0.01). Students studying vocational subjects reported significantly more sleep than students studying technological subjects (P=0.02). Univariate analyses revealed a positive relationship between sleep duration and quality of life (r=0.17, P<0.001) and an inverse relationship between sleep duration and depression (r=-0.5, P<0.001). Multivariate analyses identified depression, delayed sleep phase disorder, and medical condition as determinants of sleep duration.

CONCLUSIONS

This investigation of a large student cohort has confirmed that the average sleep duration in adolescents is far below what is recommended. Depression significantly influenced sleep duration. We recommend that a quantitative and qualitative evaluation of sleep should be made during the medical examination of any adolescent.

Adolescent Sleep Duration, Variability, and Peak Levels of Achievement and Mental Health

To inform public health recommendations for adolescent sleep, the amounts of sleep associated with the highest levels of academic achievement and mental health were examined. The degree to which daily variability in sleep duration represents an underappreciated but functionally significant sleep behavior also was tested. A total of 421 adolescents (M_age  = 15.03 years) with Mexican-American backgrounds reported nightly sleep times for 2 weeks; approximately 80% repeated the same protocol 1 year later. Multilevel modeling indicated that the amount of sleep associated with the lowest levels of internalizing and externalizing symptoms was more than 1 hr greater than the amount associated with the highest levels of academic performance. Greater daily variability in sleep duration predicted greater symptomatology and mixed academic outcomes.

Impact of different recommendations on adequacy rate for sleep duration in children

A huge amount of literature in the last decades showed that sleep is essential for children’s health and well-being and that short sleep duration is associated with several negative health outcomes. Many developmental phases in infancy and childhood are in strict relationship with an healthy sleep.

In the last years some specific recommendations made for how much sleep children need have been published. The empirical evidences for contemporary sleep recommendations has changed and the new recommendations are clearly different from the previous ones and reflect clearly the changes in the sleep need of the children and adolescents in the last decades although seem still to be largely unfitting for preadolescence and adolescence.

If sleep is to be treated as a therapeutic intervention, then consensus guidelines, statements, and evidence-based best-practice documents are needed to underpin sleep recommendations for children.

Sleep recommendations for children play an important role for public policies and interventions, and to advertise parents and children of the negative consequences of sleep deprivation/reduction.

Infant sleep hygiene counseling (sleep trial): protocol of a randomized controlled trial

BACKGROUND

Sleep problems in childhood have been found to be associated with memory and learning impairments, irritability, difficulties in mood modulation, attention and behavioral problems, hyperactivity and impulsivity. Short sleep duration has been found to be associated with overweight and obesity in childhood. This paper describes the protocol of a behavioral intervention planned to promote healthier sleep in infants.

METHODS

The study is a 1:1 parallel group single-blinded randomized controlled trial enrolling a total of 552 infants at 3 months of age. The main eligibility criterion is maternal report of the infant's sleep lasting on average less than 15 h per 24 h (daytime and nighttime sleep). Following block randomization, trained fieldworkers conduct home visits of the intervention group mothers and provide standardized advice on general practices that promote infant's self-regulated sleep. A booklet with the intervention content to aid the mother in implementing the intervention was developed and is given to the mothers in the intervention arm. In the two days following the home visit the intervention mothers receive daily telephone calls for intervention reinforcement and at day 3 the fieldworkers conduct a reinforcement visit to support mothers' compliance with the intervention. The main outcome assessed is the between group difference in average nighttime self-regulated sleep duration (the maximum amount of time the child stays asleep or awake without awakening the parents), at ages 6, 12 and 24 months, evaluated by means of actigraphy, activity diary records and questionnaires. The secondary outcomes are conditional linear growth between age 3-12 and 12-24 months and neurocognitive development at ages 12 and 24 months.

DISCUSSION

The negative impact of inadequate and insufficient sleep on children's physical and mental health are unquestionable, as well as its impact on cognitive function, academic performance and behavior, all of these being factors to which children in low- and middle-income countries are at higher risk. Behavioral interventions targeting mothers and young children that can be delivered inexpensively and not requiring specialized training can help prevent future issues by reducing the risk to which these children are exposed.

TRIAL REGISTRATION

ClinicalTrial.gov NCT02788630 registered on 14 June 2016 (retrospectively registered).

Sleep timing and child and parent outcomes in Australian 4-9-year-olds: a cross-sectional and longitudinal study

OBJECTIVES

The aim of this study is to use national Australian time-diary data to examine both (1) cross-sectionally and (2) longitudinally whether being late versus early to sleep or wake is associated with poorer child behavior, quality of life, learning, cognition and weight status, and parental mental health.

METHODS

DESIGN/SETTING

Data from the first three waves of the Longitudinal Study of Australian Children were taken.

PARTICIPANTS

A national representative sample of 4983 4-5-year-olds, recruited in 2004 from the Australian Medicare database and followed up biennially, was taken; 3631 had analyzable sleep information and a concurrent measure of health and well-being for at least one wave.

MEASURES

EXPOSURE

Parents completed 24-h child time-use diaries for one week and one weekend day at each wave. Using median splits, sleep timing was categorized into early-to-sleep/early-to-wake (EE), early-to-sleep/late-to-wake (EL), late-to-sleep/early-to-wake (LE), and late-to-sleep/late-to-wake (LL) at each wave.

OUTCOMES

The outcomes included parent-reported child behavior, health-related quality of life, maternal/paternal mental health, teacher-reported child language, literacy, mathematical thinking, and approach to learning. The study assessed child body mass index and girth.

RESULTS

(1) Using EE as the comparator, linear regression analyses revealed that being late-to-sleep was associated with poorer child quality of life from 6 to 9 years and maternal mental health at 6-7 years. There was inconsistent or no evidence for associations between sleep timing and all other outcomes. (2) Using the count of the number of times (waves) at which a child was categorized as late-to-sleep (range 0-3), longitudinal analyses demonstrated that there was a cumulative effect of late-to-sleep profiles on poorer child and maternal outcomes at the child age of 8-9 years.

CONCLUSIONS

Examined cross-sectionally, sleep timing is a driver of children's quality of life and maternal depression. Examined longitudinally, there appears to be cumulative and adverse relationships between late-to-sleep profiles and poorer child and maternal outcomes at the child age of 8-9 years. Understanding how other parameters - such as scheduling consistency, sleep efficiency and hygiene - are also related to child and parent outcomes will help health professionals better target sleep management advice to families.

Cross-sectional sleep thresholds for optimal health and well-being in Australian 4-9-year-olds

AIM

Using national Australian time-diary data, we aimed to empirically determine sleep duration thresholds beyond which children have poorer health, learning, quality of life, and weight status and parents have poorer mental health.

METHODS

DESIGN/SETTING

Cross-sectional data from the first three waves of the Longitudinal Study of Australian Children.

PARTICIPANTS

A nationally representative sample of 4983 4-5-year-olds, recruited in 2004 from the Australian Medicare database and followed biennially; 3631 had analyzable sleep information and a concurrent measure of health and well-being for at least one wave.

MAIN MEASURES

EXPOSURE

At each wave, a parent completed 24-h time-use diaries for one randomly selected weekday and one weekend day, including a "sleeping/napping" category.

OUTCOMES

Parent-reported child mental health, health-related quality of life, and maternal/paternal mental health; teacher-reported child language, literacy, mathematical thinking, and approach to learning; and assessed child body mass index and girth.

RESULTS

Linear regression analyses revealed weak, inconsistent relationships between sleep duration and outcomes at every wave. For example, children with versus without psychosocial health-related quality of life problems slept slightly less at 6-7 years (adjusted mean difference 0.12 h; 95% confidence interval 0.01-0.22, p = 0.03), but not at 4-5 (0.00; -0.10 to 0.11, p = 1.0) or 8-9 years (0.09; -0.02 to 0.22, p = 0.1). Empirical exploration using fractional polynomials demonstrated no clear thresholds for sleep duration and any adverse outcome at any wave.

CONCLUSIONS

Present guidelines in terms of children's short sleep duration appear misguided. Other parameters such as sleep timing may be more meaningful for understanding optimal child sleep.

Sleep Deprivation Is Associated with Bicycle Accidents and Slip and Fall Injuries in Korean Adolescents

Objective

This study sought to evaluate associations between sleep time and bicycle accidents, falls under various circumstances, and dental injuries in adolescents.

Methods

A total of 61,696 participants ranging from 12 to 18 years of age who completed the Korea Youth Risk Behavior Web-based Survey (KYRBWS) in 2013 were enrolled in this study. Bicycle riding accidents were analyzed for 17,232 bicycle-riding participants. Data were collected regarding the weekday sleep duration for the most recent 7 days, which was categorized as < 5.5 h, 5.5–6.5 h, 6.5–7.5 h, or ≥ 7.5 h per day, and the incidence of bicycle accidents, slips and falls under various circumstances, and dental injuries in the most recent 12 months. Adjusted odds ratios (aORs) were calculated among sleep groups for bicycle accidents, slips and falls, and dental injuries using simple and multiple logistic regression analyses with complex sampling.

Results

Bicycle riding accidents and slips and falls in classrooms, corridors, the ground, toilets, stairs, and other unspecified situations showed positive correlations with sleep deprivation. Comparisons of groups with ≥ 7.5 h sleep, < 5.5 h, 5.5–6.5 h sleep, and 6.5–7.5 h sleep revealed increased associations with slips and falls under various circumstances. In particular, the aORs were higher in the groups with less sleep (aOR of the 5.5 h group > the 5.5–6.5 h group > the 6.5–7.5 h group). There was no significant relationship between sleep deprivation and dental injury.

Conclusions

This study demonstrated that sleep deprivation among Korean adolescents was associated with bicycle accidents and falls at home and school. Thus, adequate sleep may be needed to prevent accidents and falls.

Evaluation of a sleep education program for low-income preschool children and their families

STUDY OBJECTIVES

To evaluate a novel sleep education program for low-income preschool children and their families.

DESIGN

Randomized trial of an educational intervention.

SETTING

Community-based.

PARTICIPANTS

Head Start preschool families (n = 152) in greater Lansing and Detroit, Michigan.

INTERVENTIONS

Classrooms or Head Start sites were randomized to an intervention group (prompt intervention) versus a control group (delayed intervention). Parents attended a one-time, 45-min sleep education program and preschoolers received 2 w (320 total min) of classroom sleep curriculum.

MEASUREMENTS

Parent knowledge, attitudes, self-efficacy, and beliefs were assessed as the primary outcomes just before the 45-min sleep intervention, immediately postintervention, and approximately 1 mo postintervention. Parents reported their child's bedtimes and wake times on 7-day sleep diaries at baseline and at 1-mo follow-up. Average weeknight sleep durations and bedtimes served as secondary outcomes.

RESULTS

Linear mixed models showed a time × treatment effect for parents' knowledge, attitudes, and self-efficacy (each P < 0.05) but not beliefs. These improvements were found immediately postintervention but were not retained at 1-mo follow-up. Children in the intervention group improved their weeknight sleep duration at 1-mo follow-up by 30 min (11.0 ± 0.9 h vs. 10.5 ± 1.0 hours at baseline) compared to controls (10.4 ± 0.9 h versus 10.5 ± 0.9 h at baseline) (P = 0.04 for difference between groups). Children did not show statistically significant improvements in bedtime.

CONCLUSIONS

Educational interventions in early childhood can have an effect on parents' sleep knowledge, attitudes, and self-efficacy, and on children's sleep behavior. However, repeated exposure to the new information may be important for parents as well as their children.

The complexities of defining optimal sleep: empirical and theoretical considerations with a special emphasis on children

The main aim of this paper is to consider relevant theoretical and empirical factors defining optimal sleep, and assess the relative importance of each in developing a working definition for, or guidelines about, optimal sleep, particularly in children. We consider whether optimal sleep is an issue of sleep quantity or of sleep quality. Sleep quantity is discussed in terms of duration, timing, variability and dose-response relationships. Sleep quality is explored in relation to continuity, sleepiness, sleep architecture and daytime behaviour. Potential limitations of sleep research in children are discussed, specifically the loss of research precision inherent in sleep deprivation protocols involving children. We discuss which outcomes are the most important to measure. We consider the notion that insufficient sleep may be a totally subjective finding, is impacted by the age of the reporter, driven by socio-cultural patterns and sleep-wake habits, and that, in some individuals, the driver for insufficient sleep can be viewed in terms of a cost-benefit relationship, curtailing sleep in order to perform better while awake. We conclude that defining optimal sleep is complex. The only method of capturing this elusive concept may be by somnotypology, taking into account duration, quality, age, gender, race, culture, the task at hand, and an individual's position in both sleep-alert and morningness-eveningness continuums. At the experimental level, a unified approach by researchers to establish standardized protocols to evaluate optimal sleep across paediatric age groups is required.

The effects of acute sleep restriction on adolescents' pedestrian safety in a virtual environment

PURPOSE

Over 8,000 American adolescents ages 14-15 years require medical attention owing to pedestrian injury annually. Cognitive factors contributing to pedestrian safety include reaction time, impulsivity, risk taking, attention, and decision making. These characteristics are also influenced by sleep restriction. Experts recommend that adolescents obtain 8.5 hours of uninterrupted sleep each night, but most American adolescents do not. Inadequate sleep may place adolescents at risk for pedestrian injury.

METHODS

Using a within-subjects design, 55 14- and 15-year-olds engaged in a virtual reality pedestrian environment under two conditions, scheduled a week apart: sleep-restricted (4 hours' sleep the previous night) and adequate sleep (8.5 hours). Sleep was assessed using actigraphy and pedestrian behavior via four outcome measures: time to initiate crossing, time before contact with vehicle while crossing, virtual hits or close calls and attention to traffic (looks left and right).

RESULTS

While acutely sleep restricted, adolescents took more time to initiate pedestrian crossings, crossed with less time before contact with vehicles, experienced more virtual hits or close calls, and looked left and right more often compared with when adequately rested. Results were maintained after controlling for age, gender, ethnicity, and average total sleep duration before each condition.

CONCLUSIONS

Adolescent pedestrian behavior in the simulated virtual environment was markedly different, and generally more risky, when acutely sleep restricted compared with adequately rested. Inadequate sleep may influence cognitive functioning to the extent that pedestrian safety is jeopardized among adolescents capable of crossing streets safely when rested. Policy decisions might be educated by these results.

Nighttime sleep duration and externalizing behaviors of preschool children

OBJECTIVE

To examine how many hours preschool children in the United States sleep at night and to test the hypothesis that children with shorter nighttime sleep duration are more likely to exhibit externalizing behaviors.

METHODS

The Early Childhood Longitudinal Study-Birth Cohort is a nationally representative longitudinal cohort study that followed children born in 2001 through kindergarten. This cross-sectional study examines the preschool wave (n = ∼8950). We estimated nighttime sleep duration from parent's reports of their 4-year-old child's typical weekday bed and wake times. Parents rated their child on 6 different externalizing behaviors (overactivity, anger, aggression, impulsivity, tantrums, and annoying behaviors) on a scale from 1 through 5 using the Preschool and Kindergarten Behavior Scale-second edition. Multivariable regression analyses were used to examine the association between sleep duration and behavior scores and to control for possible confounders.

RESULTS

Results are weighted to total United States population, ∼3,895,100 children born in 2001. Mean sleep duration was 10.47 hours. Mean bedtime was 8:39 PM and wake time was 7:13 AM. The adjusted odds ratios for children sleeping <9.44 hours (1 standard deviation below the mean) versus those sleeping ≥9.44 hours for 6 different externalizing behavior outcomes were as follows: overactivity = 1.30 (95% confidence interval [CI], 1.03-1.65); anger = 1.40 (95% CI, 1.15-1.71); aggression = 1.81 (95% CI, 1.36-2.41); impulsivity = 1.44 (95% CI, 1.12-1.86); tantrums = 1.46 (95% CI, 1.16-1.85); and annoying behaviors = 1.40 (95% CI, 0.97-1.87).

CONCLUSION

Shorter nighttime sleep duration in preschool children is associated with higher likelihood of externalizing behavioral symptoms based on parental report.

Children's sleep needs: is there sufficient evidence to recommend optimal sleep for children?

It is widely recognized that sleep is important for children's health and well-being and that short sleep duration is associated with a wide range of negative health outcomes. Recently, there has been much interest in whether or not there are sufficient data to support the specific recommendations made for how much sleep children need. In this article we explore concepts related to children's sleep need, discuss the theory, rationale, and empirical evidence for contemporary sleep recommendations, and outline future research directions for sleep recommendations. If sleep is to be treated as a therapeutic intervention, then consensus guidelines, statements, and evidence-based best-practice documents are needed to underpin sleep recommendations for children.

Total sleep time severely drops during adolescence

Restricted sleep duration among young adults and adolescents has been shown to increase the risk of morbidities such as obesity, diabetes or accidents. However there are few epidemiological studies on normal total sleep time (TST) in representative groups of teen-agers which allow to get normative data.