Bedtime Autonomy and Cellphone Use Influence Sleep Duration in Adolescents

Social jetlag and sleep habits in children and adolescents: Associations with autonomy (bedtime setting and electronics curfew) and electronic media use before sleep

For young people attending school, social jetlag (SJL) refers to discrepancy in sleep/wake timing between school days and weekends. This study investigated SJL in school-aged children and adolescents in England and whether this is associated with age, gender, and sleep habits including bedtimes and electronic media use. Students (school y 5-13; typical age 9-18 y) completed the 2021 OxWell Student Survey. In total 19,760 participants (55% female) reported on sleep/wake timing, rules concerning bedtime setting on school night/weekend, electronic media curfew, and frequency of social media use and video gaming before sleep intention. The mean SJL was 1 h 53 min (SD = 1 h 7 min) and peaked at 2 h 7 min at age 15. Multiple regression analysis revealed SJL was positively associated with age and being male was associated with slightly lower SJL than being female. After controlling for age and gender, weekend bedtime setting (β = 0.21), frequency of social media use before sleep (β = 0.16) and video gaming before sleep (β = 0.12) were the strongest predictors of SJL. Findings suggest that household rules regarding weekend bedtimes and less electronic media use before sleep may be connected with lower SJL as well as more regular sleep timing across the whole week.

Racial and ethnic sleep health disparities in adolescents and risk for type 2 diabetes: a narrative review

INTRODUCTION

Sleep is an essential factor for health and wellbeing in people across the age spectrum; yet many adolescents do not meet the recommended 8-10 h of nightly sleep. Unfortunately, habitually insufficient sleep, along with the metabolic changes of puberty, puts adolescents at increased risk for a host of adverse health outcomes such as obesity and type 2 diabetes (T2D). Furthermore, individuals from historically minoritized racial and ethnic groups (e.g. Hispanic/Latinx, African American/Black) are more likely to experience shorter sleep duration compared to adolescents of White/European origin, placing them at even greater risk for disparities in T2D risk.

METHODS

We conducted a literature review on the role of race and ethnicity in adolescent sleep health and its relation to cardiometabolic outcomes, specifically T2D. We use the minority stress model and the stress and coping theory as guiding theoretical frameworks to examine individual and societal level factors that may contribute to sleep health disparities and their downstream effects on T2D risk.

RESULTS

This review highlights that the unique race-related stressors adolescents from minoritized groups face may play a role in the sleep and T2D connection on a biological, psychological, and social level. However, although there has been advancement in the current research on adolescent racial and ethnic sleep health disparities in relation to T2D, mechanisms underlying these disparities in sleep health need further investigation. Addressing these gaps is crucial for identifying and mitigating sleep health disparities and T2D among racial and ethnic minority youth.

CONCLUSION

We conclude with a discussion of the implications and future research directions of racial and ethnic disparities in sleep health and T2D prevention research. A comprehensive understanding of adolescent sleep health disparities has potential to better inform preventative and educational programs, interventions, and policies that promote sleep health equity and improve cardiometabolic outcomes like T2D.

Insomnia symptoms in children and adolescents: screening for sleep problems with the two-item Sleep Condition Indicator (SCI-02)

BACKGROUND

Sleep problems are common in young people. Yet brief screening measures to identify those most in need of an intervention are lacking. This study investigated the potential of the two-item Sleep Condition Indicator (SCI-02) for screening insomnia symptoms in children and adolescents. We sought to establish whether there are distinct subgroups with different sleep profiles and whether subgroup membership varied with gender and school year group.

METHODS

Students (school years 5-13; typical age 9-18 years) in England completed the OxWell Student Survey in 2021. Sleep measures included: SCI-02, sleep onset latency (SOL), sleep duration, daytime sleepiness, and worry disrupting sleep. Latent profile analysis and multinomial logistic regression explored sleep profiles and predicted class membership.

RESULTS

In total, 29,304 participants answered sleep items. Of these, 95% provided binary gender (n = 27,802, 55% female) for analyses. Five sleep profiles emerged. The profiles, labelled "good", "moderate", or "poor" sleepers, vary by sleep quality - which includes time taken to fall asleep (SOL), amount of sleep (sleep duration), and the disruption of sleep due to worry. The profiles are then further differentiated by high levels of daytime sleepiness - labelled "sleepy". "Good Sleepers" (18,355, 66%), "Moderate Sleepers" (4825, 17.4%), "Moderate Sleepy Sleepers" (1250, 4.5%), "Poor Sleepers" (1037, 3.7%) and "Poor Sleepy Sleepers" (2335, 8.4%). Probable insomnia rates (SCI-02 ≤ 2) were high in both poor sleeper profiles (70-80%) compared with other profiles (0%) and the sample overall (9%). Compared with "Good Sleepers", all other profiles were mostly female. Daytime sleepiness - the defining characteristic of the sleepy sleeper profiles - was more common in secondary school participants than primary school.

CONCLUSIONS

The SCI-02 is an efficient, two-question measure to screen for potential sleep problems in young people. Sleep disruption was high: one in ten were experiencing poor sleep. Females and adolescents appeared more vulnerable to poor sleep and daytime sleepiness. The SCI-02 has the potential for use in school and community contexts to identify children and adolescents who may benefit from support managing their sleep.

Child, family and household characteristics associated with physical activity in Samoan children aged 3-8 years: A cross-sectional study

Physical activity is a key component of many obesity prevention strategies. The aim of this analysis was to identify child, family, and household characteristics associated with parent-reported physical activity in Samoan children aged 3-8 years. Children (n = 445; 51.2% female, mean age 5.4 years) were part of an ongoing, mixed-longitudinal study of child growth, development, and wellbeing (the Ola Tuputupua'e cohort). Bivariate analyses and multivariate generalized linear regressions were conducted to investigate the relationship of child, family, and household characteristics with physical activity level, measured using the Netherlands Physical Activity Questionnaire (NPAQ). Children were classified as being 'highly active' if they had NPAQ scores in the 75th percentile or above. Among the n = 111 children classified as 'highly active', n = 67 (60.4%) were boys. After adjusting for child, family, and household-level characteristics, hours of child sleep per night was the only variable significantly associated with odds of being highly active. Compared to children who slept less than 9 hours at night, those who slept 10-10.99 hours (OR: 5.97, 95% CI: 2.14-18.13) and 11+ hours (OR: 25.75, 95% CI: 8.14-90.12) had higher odds of being 'highly active'. Future research should examine the mechanisms driving the relationship between nighttime sleep and physical activity among Samoan children. Intervening on sleep duration and quality may improve physical activity and, in turn, obesity risk in this setting.

It's past your bedtime, but does it matter anymore? How longitudinal changes in bedtime rules relate to adolescents' sleep

This study investigated how changing or maintaining parent-set bedtimes over time relates to adolescents' sleep timing, latency, and duration. Adolescents (n = 2509; Mage  = 12.6 [0.5] years; 47% m) self-reported their sleep patterns, and whether they had parent-set bedtimes on two separate occasions in 2019 (T1; 12.6 years) and 2020 (T2; 13.7 years). We identified four groups based on parent-set bedtimes: (1) bedtime rules at both T1 and T2 (46%, n = 1155), (2) no bedtime rules at T1 nor T2 (26%, n = 656), (3) bedtime rules at T1 but not T2 (19%, n = 472), (4) no bedtime rules at T1 but a parent-set bedtime at T2 (9%, n = 226). As expected, the entire sample showed that bedtimes generally became later and sleep duration shorter across adolescence, but the change differed among the groups. Adolescents whose parents introduced bedtime rules at T2 reported earlier bedtimes and longer sleep duration (~20 min) compared with adolescents with no bedtime rules at T2. Importantly, they no longer differed from adolescents who consistently had bedtimes across T1 and T2. There was no significant interaction for sleep latency, which declined at a similar rate for all groups. These results are the first to suggest that maintaining or re-introducing a parent-set bedtime may be possible and beneficial for adolescents' sleep.

Effects of education and age on the experience of youth violence in a very low-resource setting: a fixed-effects analysis in rural Burkina Faso

OBJECTIVE

The study aimed to investigate the effects of education and age on the experience of youth violence in low-income and middle-income country settings.

DESIGN

Using a standardised questionnaire, our study collected two waves of longitudinal data on sociodemographics, health practices, health outcomes and risk factors. The panel fixed-effects ordinary least squares regression models were used for the analysis.

SETTINGS

The study was conducted in 59 villages and the town of Nouna with a population of about 100 000 individuals, 1 hospital and 13 primary health centres in Burkina Faso.

PARTICIPANTS

We interviewed 1644 adolescents in 2017 and 1291 respondents in 2018 who participated in both rounds.

OUTCOME AND EXPOSURE MEASURES

We examined the experience of physical attacks in the past 12 months and bullying in the past 30 days. Our exposures were completed years of age and educational attainment.

RESULTS

A substantial minority of respondents experienced violence in both waves (24.1% bullying and 12.2% physical attack), with males experiencing more violence. Bullying was positively associated with more education (β=0.12; 95% CI 0.02 to 0.22) and non-significantly with older age. Both effects were stronger in males than females, although the gender differences were not significant. Physical attacks fell with increasing age (β=-0.18; 95% CI -0.31 to -0.05) and this association was again stronger in males than females; education and physical attacks were not substantively associated.

CONCLUSIONS

Bullying and physical attacks are common for rural adolescent Burkinabe. The age patterns found suggest that, particularly for males, there is a need to target violence prevention at younger ages and bullying prevention at slightly older ones, particularly for those remaining in school. Nevertheless, a fuller understanding of the mechanisms behind our findings is needed to design effective interventions to protect youth in low-income settings from violence.

Adolescent sleep, distress, and technology use: weekday versus weekend

BACKGROUND

In adolescents, technology use at bedtime is linked to disrupted sleep and psychological distress. Adolescents are known to sleep later on weekends compared to weekdays but whether this leads to greater technology use, and, hence, additional psychological distress is not known. At greater risk maybe adolescents with a late compared to early chronotype, that is a preference for late versus early sleep onset and offset times.

METHOD

Self-reported measures of sleep timing, chronotype (early, neither early nor late, late), technology medium (social media/texting, TV/streaming, and gaming), and psychological distress (DASS-21) were collected from 462 students attending one Australian high school.

RESULTS

Technology use at bedtime was greater on weekends and especially in adolescents with a late chronotype. Social media/texting on weekends was predictive of delayed sleep onset times (β = .120), and shorter sleep (β = -.172). Shorter sleep on weekdays but not on weekends was associated with greater psychological distress. Technology medium and chronotype were not predictive of psychological distress.

CONCLUSIONS

This study confirmed that technology use and its impact on sleep differed on weekdays compared to weekends and that a late chronotype was associated with greater technology use. However, neither technology medium nor chronotype was found to affect psychological distress. While greater autonomy may be granted to adolescents over the weekend regarding sleep behaviour, young people, parents, and clinicians should be mindful of the link between technology use and sleep.

Digital media use and sleep in late adolescence and young adulthood: A systematic review

Despite much attention on digital media use and young peoples' sleep, the literature on digital media and its impact on sleep in older adolescents and young adults remains to be synthesized. We conducted a systematic review of studies including young people aged 16-25 years. We searched Medline, Web of Science, and CINAHL for observational studies, identifying 60 studies. These studies were assessed for methodological quality. Only studies rated as moderate or high-quality studies were included (n = 42). A narrative synthesis summarized the impact of digital media use on eight sleep outcomes: Bedtime; Sleep onset latency or problems falling asleep; Sleep duration; Early awakening; Sleep disturbance; Daytime tiredness and function; Sleep deficits; Sleep quality. In summary, digital media use was associated to shorter sleep duration and poorer sleep quality. These associations were found for general screen use and use of mobile phone, computer, internet, and social media, but not for television, game console, and tablet use. Most studies investigating bedtime or nighttime use found associations to poor sleep outcomes. Later bedtime and daytime tiredness were associated with mobile phone use at night. Additional research is warranted to draw solid conclusions about the causal direction and to understand the underlying mechanisms.

Association between trajectories of problematic mobile phone use and chronotype among Chinese college students

AIMS

This study aimed to describe the prevalence of problematic mobile phone use (PMPU) and chronotype among Chinese college students, estimate PMPU development trajectories, and further examine the effect of PMPU trajectories on chronotype.

DESIGN

In a stratified cluster sampling design, PMPU and chronotype were evaluated in 999 college students from two universities in a 2-year prospective investigation from April 2019 to April 2021, and an investigation was conducted every six months (time 1 ∼ time 5, T1 ∼ T5).

PARTICIPANTS

N = 999 college students (mean age at T1: 18.8 years (SD = 1.2), 37.7% male) took part in the study.

MEASUREMENTS

The Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use (SQAPMPU) and the Pittsburgh Sleep Quality Index (PSQI) were used to assess the PMPU and sleep quality of college students at each time point. The Morning and Evening Questionnaire (MEQ) was adopted to investigate the chronotype of college students at T5.

FINDINGS

The prevalence of PMPU at T1 ∼ T5 was 24.3%, 27.3%, 35.1%, 31.2% and 31.9%, respectively. The prevalence rates of morning types (M-types), neutral types (N-types), and evening types (E-types) were 19.1%, 70.8%, and 10.1%, respectively. Using latent growth mixture modelling, we identified three trajectories of PMPU: low-level (49.5%), moderate-level (38.6%), and high-level score trajectories (11.9%). Multivariate logistic regression analysis results showed that a trajectory with a high score was positively associated with E-types (P < 0.05). After stratification by gender, a high-level score trajectory was positively associated with E-types only among female college students (P < 0.05). There were sex differences in the association between trajectories of PMPU and chronotype.

CONCLUSION

Long-term symptoms of PMPU may be a potential risk factor for circadian rhythm disturbance among college students, and this effect was significantly different between genders.

Time Spent on Daily Activities and Its Association with Life Satisfaction among Czech Adolescents from 1992 to 2019

Life satisfaction, an important precursor of adolescents’ well-being, is linked to daily activities. Substantial changes have been noted in adolescents’ daily activities over the years, raising the question of possible consequences for life satisfaction. This study aimed to explore changes in adolescents’ life satisfaction and their time spent on daily activities (sleeping, engaging in sports, online gaming, school commuting, time spent at school) and further investigate the associations between adolescents’ life satisfaction and these daily activities. The sample comprised 2715 adolescents from birth cohorts surveyed at four time points between 1992 and 2019. Participants were administered the Daily Activities Inventory and the Berne Questionnaire on Adolescents’ Well-Being. Robust ANOVA with post hoc tests and spline regression were employed. We found cohort differences in sleep duration (8.6 h a day on average in 1992 and 7.5 in 2019). Sleep duration of 8 h and 1 h of sports activities had a beneficial effect on life satisfaction, while more than 1 h of online gaming had a negative impact. Neither school attendance nor commuting to school was associated with adolescents’ life satisfaction. The results of this study can inform public-health policies to promote sleeping and sports habits in adolescence.

Sufficient sleep duration in autistic children and the role of physical activity

LAY ABSTRACT

Higher levels of physical activity may be associated with improved sleep in children, but this relationship is still being determined, especially in autistic children. In this study, we used existing data from the 2018 National Survey of Children's Health. Caregivers of children 6-17 years old, including caregivers of autistic children, completed a questionnaire that included questions about physical activity (days active in the past week) and sleep duration. We then determined if children were obtaining the recommended hours of sleep for their age (i.e. sufficient sleep). We found that higher physical activity levels were associated with sufficient sleep duration, but this finding was weaker in autistic children. In particular, this association was not observed in autistic children with more severe autism spectrum disorder, female autistic children, and autistic children 6-12 years old. In conclusion, physical activity is a promising approach to help children obtain sufficient sleep duration. However, more personalized approaches to improving sleep may be needed for certain groups of autistic children.

Open-source Longitudinal Sleep Analysis From Accelerometer Data (DPSleep): Algorithm Development and Validation

BACKGROUND

Wearable devices are now widely available to collect continuous objective behavioral data from individuals and to measure sleep.

OBJECTIVE

This study aims to introduce a pipeline to infer sleep onset, duration, and quality from raw accelerometer data and then quantify the relationships between derived sleep metrics and other variables of interest.

METHODS

The pipeline released here for the deep phenotyping of sleep, as the DPSleep software package, uses a stepwise algorithm to detect missing data; within-individual, minute-based, spectral power percentiles of activity; and iterative, forward-and-backward-sliding windows to estimate the major Sleep Episode onset and offset. Software modules allow for manual quality control adjustment of the derived sleep features and correction for time zone changes. In this paper, we have illustrated the pipeline with data from participants studied for more than 200 days each.

RESULTS

Actigraphy-based measures of sleep duration were associated with self-reported sleep quality ratings. Simultaneous measures of smartphone use and GPS location data support the validity of the sleep timing inferences and reveal how phone measures of sleep timing can differ from actigraphy data.

CONCLUSIONS

We discuss the use of DPSleep in relation to other available sleep estimation approaches and provide example use cases that include multi-dimensional, deep longitudinal phenotyping, extended measurement of dynamics associated with mental illness, and the possibility of combining wearable actigraphy and personal electronic device data (eg, smartphones and tablets) to measure individual differences across a wide range of behavioral variations in health and disease. A new open-source pipeline for deep phenotyping of sleep, DPSleep, analyzes raw accelerometer data from wearable devices and estimates sleep onset and offset while allowing for manual quality control adjustments.

Meta-analysis of age and actigraphy assessed sleep characteristics across the lifespan

STUDY OBJECTIVES

Sleep quantity and continuity vary across the lifespan. Actigraphy is a reliable and widely-used behavioral measure of sleep in research and personal health monitoring. This meta-analysis provides a novel examination of whether age (in years) is associated with actigraphy-assessed sleep across the lifespan.

METHODS

A systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using "actigraphy" and "sleep" terms provided 7,079 titles/abstracts; studies of individuals with known psychiatric or medical comorbidities were excluded. Ninety-one articles (N = 23,365) provided data for six meta-analyses examining sleep duration (k = 89), sleep efficiency (k = 58), bedtime (k = 19) and waketime (k = 9) for individuals ages 6-21, and bedtime (k = 7) and waketime (k = 7) for individuals ages 22 and older.

RESULTS

At older ages, sleep duration was shorter (r = -0.12) and sleep efficiency was lower (r = -0.05). Older age was associated with later bedtime (r = 0.37) and wake-up time (r = 0.24) from ages 6-21, whereas older age was associated with earlier bedtime (r = -0.66) and wake-up time (r = -0.59) for ages 22 and above. The strength of these associations was modified by study continent, but not by any other moderator.

CONCLUSIONS

Age was negatively associated with actigraphy-assessed sleep duration and efficiency, but the effects were small in magnitude. On the other hand, large associations were observed between age and sleep timing, despite a smaller literature and the absence of analyzable data for ages 30-60. Changes in sleep timing, rather than changes in sleep duration or continuity, may better characterize the effects of age on human sleep.

Update on school-based sleep education programs: how far have we come and what has Australia contributed to the field?

OBJECTIVE

School-based sleep education programs help to promote sleep health information to many children and adolescents. The aim of this systematic review was to identify and describe school-based sleep education programs, to update previous reviews and identify recent advances and improvements in this field worldwide.

METHODS

Four electronic databases were searched. Eligibility criteria included children aged 5-18 years, sleep education intervention conducted in a school setting, and at least one pre-post-measure of a sleep variable.

RESULTS

A total of 32 articles met eligibility criteria with Australian sleep researchers constituting ∼ one quarter of these studies. Studies dated from 2007 to 2020 with sample sizes ranging from 9 to 3713 students. The majority of participants were high school students and predominantly female. Education programs generally took 4-6 weeks and content was consistent across studies. Overall, exposure to sleep education increased sleep knowledge, however changes in sleep behaviour variables and secondary outcome variables (eg, mental health; cognitive function; sleep hygiene practices) presented varied results. Studies conducted since 2015 were more likely to be randomised controlled trials and to include more interactive, online designs utilising innovative content such as mindfulness.

CONCLUSIONS

An exponential growth in school sleep education programs was identified since 2016. Future studies should consider utilising objective sleep measures, longer-term follow-ups, innovative delivery methods, and stronger attempts at implementing a knowledge-to-action approach for more sustainable programs.

A Model of Adolescent Sleep Health and Risk for Type 2 Diabetes

PURPOSE OF REVIEW

This paper presents a review of the current literature in support of a model explaining the relationships between sleep health and risk for type 2 diabetes in adolescents.

RECENT FINDINGS

Short sleep duration is associated with risk of developing obesity in youth. Sleep restriction increases energy expenditure, but also increases hunger, appetite, and food intake, causing positive energy balance, impacting appetite-regulating hormones, and leading to increased eating late at night. Insufficient sleep may lead to reduced physical activity and greater sedentary behaviors. In addition, short sleep duration is associated with reduced insulin sensitivity. The cumulative negative consequences of insufficient sleep increase risk for type 2 diabetes. Applications to clinical care, public policy, and future research are discussed. Insufficient sleep in adolescence increases risk for type 2 diabetes directly through impact on insulin sensitivity and indirectly through increased dietary intake, sedentary activity, and weight gain.

Modifiable parental factors in adolescent sleep: A systematic review and meta-analysis

Sleep problems are prevalent during adolescence, but parents may be able to support adolescents to sleep better. A systematic search of records from six databases from inception up to November 2019, identified 103 peer-reviewed publications that examined behaviourally and cognitively modifiable parental factors associated with sleep in adolescents aged 12-18 years. Although included studies were largely cross-sectional and heterogeneous, with heavy reliance on self-reported measures, associations with sound, convergent levels of evidence were found for: 1) parental rule-setting for bedtimes and parent sleep behaviours with longer sleep duration in adolescents; 2) healthy parent sleep and family functioning with better adolescent sleep quality; and 3) parental warmth with better adolescent daytime functioning. Effect sizes were in the small to moderate range. The identified parental factors are recommended targets for inclusion in parenting programs to support adolescent sleep, however, would require validation in intervention studies. Opportunities for research are outlined for the identified parental factors, sleep domains with limited evidence, and better understanding the mechanisms or possible moderators in the associations between parental factors and sleep outcomes.

Prevalence and correlates of adherence to the combined movement guidelines among Czech children and adolescents

Background

There are limited studies on the prevalence of adherence to the combined guidelines for physical activity (PA), sedentary behavior, and sleep in children and adolescents. Moreover, little is known about correlates of adherence to the guidelines. Therefore, the main aim of this study is to examine the prevalence and identify the correlates of adherence to the combined movement guidelines among children and adolescents.

Methods

A total of 355 children aged 8–13 years (44% boys) and 324 adolescents aged 14–18 years (43% boys) from the Czech Republic participated in this study. PA and sleep duration were estimated using multi-day 24-h raw data from wrist-worn accelerometers. Recreational screen time was parent proxy-reported in children and self-reported in adolescents. Seventeen potential correlates were grouped into three homogenous categories for biological and cognitive, behavioral, and family correlates. The multi-level multivariable logistic regression was applied to identify correlates of adherence to combined movement guidelines and to specific combinations of any of two recommendations.

Results

Approximately 6.5% of children and 2.2% of adolescents met all recommendations of the combined movement guidelines. In children, girls (OR = 0.4; 95% CI = 0.1–0.9) and participants with overweight or obese fathers (OR = 0.3; 95% CI = 0.1–0.7) had significantly lower odds of adherence to the combined movement guidelines. Additionally, children had higher odds of meeting specific combinations of two recommendations if they reported regular fruit and vegetable intake, participated in organized PA, or if their fathers had a university degree. Meanwhile, paternal overweight and obesity, and high sleep efficiency were associated with lower odds of meeting specific combinations of recommendations. In adolescents, sex, fruit and vegetable intake, organized PA, and active play were correlates of meeting specific combinations of any two recommendations.

Conclusions

A low proportion of children and adolescents met the combined movement guidelines and several correlates related to family were identified. Family is a key source of influence for healthy movement behaviors during childhood and adolescence.

Is adherence to the 24-hour movement guidelines associated with a reduced risk of adiposity among children and adolescents?

BACKGROUND

Little is known about the combined effect of physical activity (PA), recreational screen time (ST), and sleep in preventing childhood obesity. Hence, this study aimed to analyze the associations between meeting the PA, ST, and sleep recommendations within the 24-hour movement guidelines and adiposity indicators among children and adolescents.

METHODS

A total of 679 children and adolescents aged 8-18 years were included. The time spent in moderate-to-vigorous PA and the sleep duration were estimated from raw data from a wrist-worn accelerometer. Recreational ST was reported by the child or parent. Body mass index (BMI) z-score, fat mass percentage (FM%), and visceral adipose tissue (VAT) were used as adiposity indicators. Participants with ≥ 60 min/day of moderate-to-vigorous PA, < 2 h/day of recreational ST, and uninterrupted sleep for 9-11 h/day (for children) or 8-10 h/day (for adolescents) were considered to meet the overall 24-hour movement guidelines.

RESULTS

Meeting the ST only recommendation was associated with reduced odds of a high BMI z-score (odds ratio [OR] = 0.38, 95% confidence interval [CI]: 0.17-0.89), excess FM% (OR = 0.34, 95% CI: 0.13-0.93), and excess VAT (OR = 0.27, 95% CI: 0.10-0.74) in adolescents. Significantly reduced odds of a high BMI z-score was associated with meeting the combination of the ST and sleep recommendations (OR = 0.11, 95% CI: 0.01-0.89). Adolescents who met one recommendation (OR = 0.51, 95% CI: 0.27-0.96) or any two recommendations (OR = 0.33, 95% CI: 0.11-0.94) had reduced ORs of having a high BMI z-score. Adolescents had lower odds of having excess VAT if they met one recommendation (OR = 0.39, 95% CI: 0.19-0.81) or any two recommendations (OR = 0.25, 95% CI: 0.07-0.90). No significant associations were found in children.

CONCLUSIONS

The present study showed no associations between meeting all three recommendations within the 24-hour movement guidelines and adiposity indicators. However, meeting ST only recommendation and the combination of the ST and sleep recommendations was associated with a reduced risk of excess adiposity. This finding should be considered when designing effective strategies and interventions to prevent childhood obesity.

Effortful Control Moderates the Relation Between Electronic-Media Use and Objective Sleep Indicators in Childhood

Electronic-media use is associated with sleep disruptions in childhood and adolescence, although research relies primarily on subjective sleep. Effortful control, a dimension of self-regulation, may mitigate this association by helping children disengage from and regulate responses to media. We examined associations between media use and multiple actigraph-measured sleep parameters at mean and day levels and tested children's effortful control as a moderator of mean-level relations. We collected actigraph data and parents' diary reports of children's prebedtime television, video-game, laptop, desktop, cell-phone, and tablet use in 547 twin children (7-9 years old; 51.74% female). Mean-level media use was associated with bedtime and sleep duration. For the proportion of nights on which twins used media, but not the average number of media types, effortful control attenuated associations between media use and reduced sleep duration and efficiency. Day-level media use was related only to bedtime. Findings replicate and extend existing research and highlight self-regulation as a potential protective factor.

Afternoon School Start Times Are Associated with a Lack of Both Social Jetlag and Sleep Deprivation in Adolescents

The delayed circadian timing of adolescents creates a conflict with early school start times (SSTs). We used wrist actimetry to compare sleep parameters and routine nighttime activities in middle school students attending either a morning (0700 to 1200 h) or an afternoon (1230 to 1730 h) school shift. On school days, students from both shifts (n = 21 for morning shift, n = 20 for afternoon shift, ages 12-14 years) had a similar sleep onset, but morning-shift students had an earlier sleep offset and a 1 h 45 min shorter sleep duration than their afternoon peers, who slept the recommended 8 to 10 h of daily sleep. Only morning-shift students had afternoon naps, but this afternoon sleep was not sufficient to overcome sleep deprivation. On weekends, sleep onsets and offsets did not differ between shifts. Because only morning-shift students woke up later and slept longer (2 h 3 min) on weekends, they were also the only ones who experienced social jetlag. Daily surveys on their nighttime (from 1800 to 0600 h) activities indicated there was no difference between shifts in the time spent on leisure or using electronic media during school days, but students from both shifts spent more time in these activities during the weekend. Our study confirms that early SST in adolescents is associated with sleep deprivation and suggests that schedules that start much later than typically considered may be needed to eliminate sleep deprivation in adolescents.

Parents still matter: the influence of parental enforcement of bedtime on adolescents’ depressive symptoms

Study Objectives

The aim of the current study was to test a multilevel mediation model that examined how adolescent sleep duration might be linked to depressive symptoms via their daytime energy levels. Furthermore, the study examined how parents’ enforcement of various types of bedtime rules predicted the duration of adolescent sleep.

Methods

A total of 193 adolescent (ages 14–17; Mage = 15.7 years old, SD = .94; 54.4% female; 71% Caucasian) and parent dyads completed baseline, online surveys, and adolescents also completed online 7-day, twice-daily (i.e. morning and evening) reports of their sleep duration (morning diary) and their energy levels and depressive symptoms throughout the day (evening diary). Parents (Mage = 47.6 years old, SD = 5.4; 80% female) completed assessments of enforcement of bedtime-related rules (i.e. bedtime, cessation of electronic media usage, prohibiting afternoon/evening caffeine consumption). Multilevel modeling enabled the testing of the mediation model both at the between-person level and within individuals.

Results

Results suggested that adolescents’ energy levels mediated the association between adolescents’ sleep duration and depressive symptoms. Furthermore, both greater enforcement of bedtimes and later school start times predicted longer sleep durations for adolescents, and were indirectly associated with adolescents’ depressive symptoms.

Conclusions

These findings underscore the importance of adolescents obtaining sufficient sleep to support their mental health and suggest a critical point of intervention for preventing or decreasing insufficient sleep. Given the diverse threats to adolescents’ sleep as well as adolescents’ desire for greater independence, collaborative, autonomy-promoting bedtime limit-setting is recommended to support adolescents’ well-being.

Using big data to explore worldwide trends in objective sleep in the transition to adulthood

BACKGROUND

Development induces changes in sleep, and its duration has been reported to change as a function of aging. Additionally, sleep timing is a marker of pubertal maturation, where during adolescence, the circadian rhythm shifts later. Typically, this is manifested in a later sleep onset in the evening and later awakening in the morning. These changes across development seem to be universal around the world but are unlikely to persist into adulthood.

METHODS

This study utilized accelerometer data from 17,355 participants aged 16-30 years (56% female) measured by validated Polar wearables over a 14-day period. We compared sleep duration, chronotype (sleep midpoint) and weekend catch-up (ie, social jetlag) sleep across ages and regions over 242,948 nights.

RESULTS

The data indicate a decline in sleep duration as well as a dramatic shift in sleep onset times throughout adolescence. This continues well into early adulthood and stabilizes nearer age 30. Differences in sleep duration across ages were significant, and ranged from 7:53 h at age 16 to 7:29 h at age 30 in the sample. Additionally, there was a clear difference between females and males throughout adolescence and young adulthood: girls had longer sleep duration and earlier timed sleep in the current study. Differences in sleep were found between regions across the world, and across European areas.

CONCLUSIONS

Both sleep duration and sleep timing go through a clear developmental pattern, particularly in early adulthood. Females had an earlier sleep midpoint and obtained more sleep. Regional differences in sleep occurred across the world.

Does splitting sleep improve long-term memory in chronically sleep deprived adolescents?

Sleep aids the encoding and consolidation of declarative memories, but many adolescents do not obtain the recommended amount of sleep each night. After a normal night of sleep, there is abundant evidence that a daytime nap enhances the consolidation of material learned before sleep and also improves the encoding of new information upon waking. However, it remains unclear how learning is affected when sleep is split between nocturnal and daytime nap periods during a typical school week of restricted sleep. We compared long-term memory in 58 adolescents who underwent two simulated school weeks of suboptimal continuous (6.5 h nocturnal sleep opportunity) or split sleep (5 h nocturnal sleep +1.5 h daytime nap at 14:00). In the first week, participants encoded pictures in the late afternoon on Day 5 and were tested after 2-nights of recovery sleep. On 3 consecutive days in the second week, participants learned about six species of amphibians in the morning, and six different amphibians in the late afternoon. Testing was performed in the evening following a night of recovery sleep. In the first week, the split sleep group recognized more pictures. In the second week, they remembered more facts about species learned in the afternoon. Groups did not differ for species learned in the morning. This suggests that under conditions of sleep restriction, a split sleep schedule benefits learning after a nap opportunity without impairing morning learning, despite less preceding nocturnal sleep. While not replacing adequate nocturnal sleep, a split sleep schedule may be beneficial for chronically sleep restricted learners.