The impact of school daily schedule on adolescent sleep

Seasonal and Weekly Patterns of Korean Adolescents' Web Search Activity on Insomnia: Retrospective Study

BACKGROUND

Sleep deprivation in adolescents is a common but serious public health issue. Adolescents often have a progressive circadian delay and suffer from insufficient sleep during weekdays due to the school schedule. Temporal patterns in internet search activity data can provide relevant information for understanding the characteristic sleep problems of the adolescent population.

OBJECTIVE

We aimed to reveal whether adolescents exhibit distinct temporal seasonal and weekly patterns in internet search activity on insomnia compared to adults.

METHODS

We hypothesized that adolescents exhibit larger variations in the internet search volume for insomnia, particularly in association with the school schedule (e.g., academic vacations and weekends). We extracted the daily search volume for insomnia in South Korean adolescents (13-18 years old), adults (19-59 years old), and young adults (19-24 years old) during the years 2016-2019 using NAVER DataLab, the most popular search engine in South Korea. The daily search volume data for each group were normalized with the annual median of each group. The time series of the search volume was decomposed into slow fluctuation (over a year) and fast fluctuation (within a week) using fast Fourier transform. Next, we compared the normalized search volume across months in a year (slow fluctuation) and days in a week (fast fluctuation).

RESULTS

In the annual trend, 2-way ANOVA revealed a significant (group) × (month) interaction (P<.001). Adolescents exhibited much greater seasonal variations across a year than the adult population (coefficient of variation=0.483 for adolescents vs 0.131 for adults). The search volume for insomnia in adolescents was notably higher in January, February, and August, which are academic vacation periods in South Korea (P<.001). In the weekly pattern, 2-way ANOVA revealed a significant (group) × (day) interaction (P<.001). Adolescents showed a considerably increased search volume on Sunday and Monday (P<.001) compared to adults. In contrast, young adults demonstrated seasonal and weekly patterns similar to adults.

CONCLUSIONS

Adolescents demonstrate distinctive seasonal and weekly patterns in internet searches on insomnia (ie, increased search in vacation months and weekend-weekday transitions), which are closely associated with the school schedule. Adolescents' sleep concerns might be potentially affected by the disrupted daily routine and the delayed sleep phase during vacations and weekends. As we demonstrated, comparing various age groups in infodemiology and infoveillance data might be helpful in identifying distinctive features in vulnerable age groups.

Lifestyle Elements for Improving Mental and Physical Health in Japanese University Students: Subjective Sleep Quality is a Common Key Factor

This study aimed to reveal the key lifestyle elements that improve physical and mental health in university students by focusing on physical activity, nutrition, and sleep. This cross-sectional study was conducted between October 2021 and December 2021. The participants were 290 first-year students (mean age, 18.63 ± .63 years; age range, 18 to 23; 198 female). The outcomes were daily step counts measured using accelerometers, dietary intake by nutrient category, sleep duration, subjective sleep quality, exercise frequency and duration by exercise type, screen time, depression level, and subjective fatigue by body part. Depression and subjective eye fatigue represent mental and physical health outcomes. Subjective sleep quality predicted depression (β = -1.22, P < .001) and eye fatigue (β = -.23, P < .01) in the path analysis. Participants with higher subjective sleep quality performed more frequent aerobic exercise (P < .01), longer session times of physical relaxation exercise (P < .05), and shorter screen time (P < .05). Subjective sleep quality could be a key factor for high mental and physical health. Furthermore, performing aerobic and relaxation exercises and reducing screen time are important for improving the subjective sleep quality.

Effects of rapid maxillary expansion on sleep disturbance scale for children: A longitudinal CASE-series study

OBJECTIVE

To evaluate the effects of rapid maxillary expansion (RME) on Sleep Disturbance Scale for Children (SDSC) with maxillary atresia.

MATERIALS AND METHODS

The sample consisted of 27 paediatric patients evaluated through a Brazilian version of the SDSC, answered by their guardians at the following experimental time points: T0 (before installing the Hyrax expander), T1 (on the day of expander stabilization), T2 (3 months after expander stabilization), T3 (immediately after expander removal, following 6 months of retention), and T4 (3 months post-retention). Multilevel Poisson analysis adjusted for repeated measures was performed to compare outcomes across the assessment time points.

RESULTS

The mean age of patients was 9.1 years (SD = 1.46). The total SDSC scores decreased and were statistically significant from T2 onwards (P < .01), with a decrease of 24% at T4 compared with T1 (IRR 0.76; 95% CI 0.69-0.84). The mean scores at T4 were already lower than the cutoff point for risk of sleep disorders. Regarding the specific domains, there was a significant reduction in sleep breathing disorders, sleep-wake transition disorders, and disorders of excessive somnolence as of T2 (P < .01), T3 (P < .05) and T4 (P < .05), respectively.

CONCLUSION

RME in children with maxillary atresia had a positive effect on the reduction of total SDSC scores after 3 months of expander stabilization, sustained over 6 and 9 months and significant reduction in sleep breathing disorders domain, sleep-wake transition disorders domain, and disorders of excessive somnolence domain over time points.

Cardiorespiratory fitness and circadian rhythms in adolescents: a pilot study

Although cardiorespiratory fitness (CRF), an important marker of youth health, is associated with earlier sleep/wake schedule, its relationship with circadian rhythms is unclear. This study examined the associations between CRF and rhythm variables in adolescents. Eighteen healthy adolescents (10 females and 8 males; Mage = 14.6 ± 2.3 yr) completed two study visits on weekdays bracketing an ambulatory assessment during summer vacation. Visit 1 included in-laboratory CRF assessment (peak V̇o2) using a ramp-type progressive cycle ergometry protocol and gas exchange measurement, which was followed by 7-14 days of actigraphy to assess sleep/wake patterns and 24-h activity rhythms. During Visit 2, chronotype, social jetlag (i.e., the difference in midsleep time between weekdays and weekends), and phase preference were assessed using a questionnaire, and hourly saliva samples were collected to determine the dim light melatonin onset (DLMO) phase. All analyses were adjusted for sex, pubertal status, and physical activity. Greater peak V̇o2 was associated with earlier sleep/wake times and circadian phase measures, including acrophase, UP time, DOWN time, last activity peak (LAP) time, and chronotype (all P < 0.05). Peak V̇o2 was negatively associated with social jetlag (P = 0.02). In addition, the mixed-model analysis revealed a significant interaction effect between peak V̇o2 and actigraphy-estimated hour-by-hour activity patterns (P < 0.001), with the strongest effects observed at around the time of waking (0600-1000). In healthy adolescents, better CRF was associated with an earlier circadian phase and increased activity levels notably during the morning. Future studies are needed to investigate the longitudinal effects of the interactions between CRF and advanced rhythms on health outcomes.NEW & NOTEWORTHY In healthy adolescents, better cardiorespiratory fitness, as assessed by the gold standard measure [laboratory-based assessment of peak oxygen consumption (V̇o2)], was associated with earlier circadian timing of sleep/wake patterns, rest-activity rhythms and chronotype, and less social jetlag. These findings highlight the close interrelationships between fitness and rhythms and raise the possibility that maintaining higher cardiorespiratory fitness levels alongside earlier sleep/wake schedule and activity rhythms may be important behavioral intervention targets to promote health in adolescents.

The Impact of Longitudinal Patterns of Adolescent Sleep Duration on Adult C-Reactive Protein (CRP), Waist-To-Height Ratio, and Body Mass Index (BMI) Among Black and White Individuals

PURPOSE

To assess the impact of longitudinal adolescent sleep duration on adult C-reactive protein (CRP), waist-to-height ratio (WtHR), and body mass index (BMI) by race.

METHODS

Participants (N = 2,399; Mage = 15.7; 40.2% male; 79.2% White, 20.8% Black; Grades 7-12 at Wave I) from the Add Health database provided self-reported sleep duration in Waves I-IV. During Wave V, CRP, WtHR, and BMI were objectively measured. Trajectory analysis was performed using a group-based modeling approach. Chi-square test determined racial differences between groups. General linear models determined relationships between trajectory group, race, and group/race interaction with Wave V CRP, WtHR, and BMI.

RESULTS

Three sleep trajectories emerged: Group 1 "shortest" (24.4%), Group 2 "stable recommended" (67.6%), and Group 3 "varied" (8%). Black individuals and older individuals were more likely to be in Group 1 compared with Group 2. Regardless of race, individuals with patterns of sleep duration increasing to above what is recommended across waves (Group 3) had elevated CRP. Individuals with stable patterns of adequate sleep (Group 2) had lower WtHR. Black individuals with consistently stable patterns of adequate sleep duration had lower BMI compared to those with low sleep duration.

DISCUSSION

Black individuals were more likely to obtain chronically short sleep during the transition from adolescence to adulthood, highlighting a significant health disparity. Poor longitudinal sleep predicted elevated CRP and WtHR. Sleep only impacted BMI for Black individuals. This may relate to racial differences in BMI measurement.

The developmental trajectory of sleep in children with Smith-Magenis syndrome compared to typically developing peers: a 3-year follow-up study

Study Objectives

To determine the trajectory of: (i) objective sleep parameters and (ii) caregiver-reported sleep questionnaire scores over 3 years in children with Smith-Magenis syndrome (SMS) compared to age-matched typically developing (TD) controls. We also aimed to (iii) describe individual profiles of change in sleep parameters over time.

Methods

Week-long, overnight actigraphy and questionnaire data from 13 children with SMS and 13 age-matched TD children were collected at Time 1 and Time 2 (3 years later). Independent samples t-tests, paired samples t-tests, and Bayesian analyses were used to compare sleep parameters and sleep questionnaire scores between groups at each time point and compare data within groups to assess change over time.

Results

Sleep parameters were consistently more disrupted in the SMS group than the TD group, with significantly reduced sleep efficiency, increased wake after sleep onset and earlier get up times at both time points. This was mirrored in the questionnaire data, with children with SMS evidencing higher scores for overall sleep disturbance, night waking, and daytime sleepiness. While TD sleep parameters demonstrated expected developmental changes over 3 years, in the SMS group sleep parameters and variability between and within children remained largely stable. However, some children with SMS showed substantial variation in sleep parameters over time. Questionnaire scores remained stable over 3 years in both groups.

Conclusions

Overall, sleep disturbance appears to be a stable feature of SMS, indicative of a divergent sleep trajectory compared to TD peers. Proactive intervention approaches should be considered for poor sleep in SMS.

Sleep duration change among adolescents in Canada: Examining the impact of COVID-19 in worsening inequity

Purpose

The purpose of this study was to assess if adolescent sub-populations in Canada (i.e., based on race/ethnicity, sex/gender, socioeconomic status, and urbanicity groups) experienced a larger change in sleep duration and guideline adherence between 2019 and 2020 (pre-pandemic) and the 2020-2021 (mid-pandemic) school years.

Methods

Longitudinally linked data from 2019 to 2020 (pre-pandemic) and 2020-2021 (mid-pandemic) of a prospective cohort study of secondary school students (M = 14.2, SD = 1.3 years, N = 8209) in Canada were used for analyses. Regression modelling tested the main effects of race/ethnicity, sex/gender, socioeconomic status, and urbanicity on changes in sleep duration as well as adherence to Canada's 24-h Movement Guidelines for sleep (8-10 h/night). Interactions between identity variables (race/ethnicity or sex/gender) and other main effect variables were subsequently tested.

Results

Females gained more sleep (4.5 [1.5, 7.5] min/day more) and increased guideline adherence (AOR = 1.16 [1.04, 1.30] than males on average. Asian race/ethnic identity was associated with less sleep gain than White identity -10.1 [-19.4, -0.8], but not guideline adherence. Individuals in large urban areas gained less sleep and adhered less to guidelines than individuals from any other level of urbanicity (-21.4 [-38.5, -4.2] to -15.5 [-30.7, -0.2] min/day). Higher individual SES scores were associated with greater sleep gain (linear trend: 11.16 [1.2-21.1]). The discrepancies in sleep gain and guideline adherence between males and females were significantly modified by race/ethnicity and urbanicity.

Discussion

Increases in sleep duration may be one of the few benefits to adolescents during the COVID-19 pandemic but were not equally distributed across sub-populations. Efforts to promote better sleep adherence may need to account for sex/gender differences, especially in less urbanized areas and certain racial/ethnic groups.

Circadian, Reward, and Emotion Systems in Teens prospective longitudinal study: protocol overview of an integrative reward-circadian rhythm model of first onset of bipolar spectrum disorder in adolescence

BACKGROUND

Bipolar spectrum disorders (BSDs) are associated with a heightened sensitivity to rewards and elevated reward-related brain function in cortico-striatal circuitry. A separate literature documents social and circadian rhythm disruption in BSDs. Recently, integrated reward-circadian models of BSDs have been proposed. These models draw on work indicating that the two systems influence each other and interact to affect mood functioning. When dysregulated, reward and circadian system signaling may combine to form a positive feedback loop, whereby dysregulation in one system exacerbates dysregulation in the other. Project CREST (Circadian, Reward, and Emotion Systems in Teens) provides a first systematic test of reward-circadian dysregulation as a synergistic and dynamic vulnerability for first onset of BSD and increases in bipolar symptoms during adolescence.

METHODS

This NIMH-funded R01 study is a 3-year prospective, longitudinal investigation of approximately 320 community adolescents from the broader Philadelphia area, United States of America. Eligible participants must be 13-16 years old, fluent in English, and without a prior BSD or hypomanic episode. They are being selected along the entire dimension of self-reported reward responsiveness, with oversampling at the high tail of the dimension in order to increase the likelihood of BSD onsets. At Times 1-6, every 6 months, participants will complete assessments of reward-relevant and social rhythm disruption life events and self-report and diagnostic assessments of bipolar symptoms and episodes. Yearly, at Times 1, 3, and 5, participants also will complete self-report measures of circadian chronotype (morningness-eveningness) and social rhythm regularity, a salivary dim light melatonin onset (DLMO) procedure to assess circadian phase, self-report, behavioral, and neural (fMRI) assessments of monetary and social reward responsiveness, and a 7-day ecological momentary assessment (EMA) period. During each EMA period, participants will complete continuous measures of sleep/wake and activity (actigraphy), a daily sleep diary, and three within-day (morning, afternoon, evening) measures of life events coded for reward-relevance and social rhythm disruption, monetary and social reward responsiveness, positive and negative affect, and hypo/manic and depressive symptoms. The fMRI scan will occur on the day before and the DLMO procedure will occur on the first evening of the 7-day EMA period.

DISCUSSION

This study is an innovative integration of research on multi-organ systems involved in reward and circadian signaling in understanding first onset of BSD in adolescence. It has the potential to facilitate novel pharmacological, neural, and behavioral interventions to treat, and ideally prevent, bipolar conditions.

Cognitive control, bedtime patterns, and testing time in female adolescent students: behavioral and neuro-electrophysiological correlates

Introduction

Shorter and/or disrupted sleep during adolescence is associated with cognitive and mental health risks, particularly in females. We explored the relationship between bedtime behavior patterns co-varying with Social Jet Lag (SJL) and School Start Times (SST) and neurocognitive performance in adolescent female students.

Methods

To investigate whether time of day (morning vs. afternoon), early SSTs and days of the school week can be correlated with neurocognitive correlates of sleep insufficiency, we recruited 24 female students aged 16-18 to report sleep logs, and undergo event-related electroencephalographic recordings on Monday, Wednesday, mornings, and afternoons. Using a Stroop task paradigm, we analyzed correlations between reaction times (RTs), accuracy, time of day, day of week, electroencephalographic data, and sleep log data to understand what relationships may exist.

Results

Participants reported a 2-h sleep phase delay and SJL. Stroop interference influenced accuracy on Monday and Wednesday similarly, with better performance in the afternoon. For RTs, the afternoon advantage was much larger on Monday than Wednesday. Midline Event-Related Potentials (ERPs) yielded higher amplitudes and shorter latencies on Wednesday morning and Monday afternoon, in time windows related to attention or response execution. A notable exception were delayed ERP latencies on Wednesday afternoon. The latter could be explained by the fact that delta EEG waves tended to be the most prominent, suggesting heightened error monitoring due to accumulating mental fatigue.

Discussion

These findings provide insights into the interaction between SJL and SST and suggest evidence-based criteria for planning when female adolescents should engage in cognitive-heavy school activities such as tests or exams.

Santos I, Matijasevich A, Tovo-Rodrigues L. Sleep Duration in Adolescence and Its Prenatal, Perinatal, and Health Determinants in a Large Population-based Cohort Followed from Birth

Objective  To investigate sleep duration and its associated factors in adolescents aged 11 years from the 2004 Pelotas (Brazil) Birth Cohort Study. Methods  Sleep duration was assessed using a self-report sleep habits. Independent variables included perinatal, sociodemographic, behavioral, and health characteristics. The associations were estimated using multiple linear regression. Results  The mean sleep duration of 3,179 adolescents was 9.3 hour (SD =1.7 hour). Longer sleep duration was associated with lower socioeconomic status at birth (β: 0.37, 95% CI: 0.12; 0.61), lower mother's education level ( p  < 0.001), and being female (β: 0.19, 95% CI: 0.06; 0.33). Shorter sleep duration was associated with cesarean section delivery (β: -0.16, 95% CI: -0.31; -0.02); having classes in the morning shift (β: -1.38, 95% CI: -1.51; -1.26), and lower terciles of physical activity ( p  = 0.04). Conclusions  The mean sleep duration observed in this study was consistent with the international recommendations for this age range. Adolescents from lower income families, who are more active, study in shifts other than morning, girls, and those born through vaginal delivery presented higher sleep duration than their counterparts.

Gender differences in the interference of sleep difficulties and daytime sleepiness on school and social activities in adolescents

OBJECTIVES

During adolescence, changes in the circadian and homeostatic systems, combined with psychosocial factors, create a phase delay in the sleep of adolescents. These changes in sleep are associated with increased sleep difficulties and a shortened sleep duration, which has a negative impact on daytime functioning of adolescents. Some studies showed that teenage girls report worse sleep quality and shorter sleep duration than boys during adolescence. The objective of this study was to investigate gender differences in the impact of sleep difficulties and sleepiness on daytime functioning in adolescents and to measure which aspect of sleep may interfere with daytime functioning in boys and girls.

METHOD

A total of 731 adolescents (311 boys, 420 girls; age 13 to 17,5 years) completed questionnaires on sleep and daytime functioning.

RESULTS

Compared to boys, teenage girls reported a significantly greater impact of short sleep duration and sleep difficulties on their school and social activities. Furthermore, our results suggest that the factors predicting the negative interference on daytime functioning seem to be more complex and multifactorial for girls than for boys.

CONCLUSIONS

This study further emphasizes the importance of monitoring insufficient and poor sleep quality in adolescents, as these sleep variables seem to have a significant impact on their daytime functioning. Clinicians should also take into account gender when considering sleep issues in adolescents, as teenage girls and boys have different vulnerabilities and needs.

Patterns of sleep disturbances and associations with depressive symptoms in autistic young adults

Autistic individuals are at an increased risk for both sleep disturbances and depression. While studies in the general population and in autistic adults have drawn general links between sleep disturbances and mental health, few studies have examined the extent to which specific sleep problems may be implicated in the extremely high rates of depression among autistic adults. This study aimed to describe the patterns of sleep disturbances in autistic young adults, and their associations with depressive symptoms while controlling for relevant demographic factors. A sample of 304 legally independent adults (age 18-35 years old) with a childhood diagnosis of autism spectrum disorder self-reported on their average sleep behaviors during the past week and depressive symptoms on the Beck Depressive Inventory-II. A significant proportion (86.01%) of autistic young adults experienced at least one of the primary sleep disturbances of interest, including short total sleep time (39.59%), poor sleep efficiency (60.07%), and delayed sleep phase (36.18%). Additionally, lower sleep efficiency and delayed sleep phase were both associated with higher depressive symptoms. The associations between sleep and depressive symptoms identified in our study suggest that sleep treatments may hold potential for ameliorating depressive symptoms in autistic adults who also experience sleep problems. Further research using daily sleep diaries and objective measures of sleep behaviors, as well as longitudinal studies, are needed to understand how changes in sleep may relate to changes in depressive symptoms in autistic adults.

Do both timing and duration of screen use affect sleep patterns in adolescents?

BACKGROUND

Sleep duration has declined in adolescents over the last 30 years and screen use has been identified as a risk factor. Studies have examined the duration of screen use and screen-based activities but have not differentiated between evening and night-time use.

METHODS

Cross sectional questionnaire survey of adolescents recruited in schools. Sleep habits on school nights and weekends, symptoms of insomnia and daytime repercussions were recorded using an online questionnaire administered in the classroom setting. Sleep deprivation (<7 hours in bed /night), school night sleep restriction (≥2 hours difference in sleep duration on school nights vs weekends), excessive sleepiness (score >6 on a visual analogue scale), duration of screen use and timing of screen use (evening vs after bedtime) were determined.

RESULTS

2513 students (53.4% female, median age 15 years) were included. 20% were sleep deprived and 41% sleep restricted. A clear dose effect relationship in a model controlling for age, sex, school level and sociodemographic class was seen with all levels of night-time screen use on sleep deprivation and sleep restriction (>2 hours use sleep deprivation OR 5.23[3.03-9.00]. sleep restriction OR 2.05[1.23-3.42]) and > 2 hours evening use (>2 hours use sleep deprivation OR 2.72[2.15-3.44] sleep restriction OR 1.69[1.36-2.11]) but not moderate evening use. All night-time use and > 2 hours evening use increased the risk of insomnia, non refreshing sleep, and affected daytime function (daytime sleepiness, lack of energy and irritability).

CONCLUSIONS

Both duration of screen use and timing are associated with adverse effects on sleep and daytime functioning in adolescents. More than 2 hours evening use and all night-time use should be avoided.

Alerting effects of light in healthy individuals: a systematic review and meta-analysis

Light plays an essential role in psychobiological and psychophysiological processes, such as alertness. The alerting effect is influenced by light characteristics and the timing of interventions. This meta-analysis is the first to systematically review the effect of light intervention on alertness and to discuss the optimal protocol for light intervention. In this meta-analysis, registered at PROSPERO (Registration ID: CRD42020181485), we conducted a systematic search of the Web of Science, PubMed, and PsycINFO databases for studies published in English prior to August 2021. The outcomes included both subjective and objective alertness. Subgroup analyses considered a variety of factors, such as wavelength, correlated color temperature (CCT), light illuminance, and timing of interventions (daytime, night-time, or all day). Twenty-seven crossover studies and two parallel-group studies were included in this meta-analysis, with a total of 1210 healthy participants (636 (52%) male, mean age 25.62 years). The results revealed that light intervention had a positive effect on both subjective alertness (standardized mean difference (SMD) = –0.28, 95% confidence interval (CI): –0.49 to –0.06, P = 0.01) and objective alertness in healthy subjects (SMD = –0.34, 95% CI: –0.68 to –0.01, P = 0.04). The subgroup analysis revealed that cold light was better than warm light in improving subjective alertness (SMD = –0.37, 95% CI: –0.65 to –0.10, P = 0.007, I² = 26%) and objective alertness (SMD = –0.36, 95% CI: –0.66 to –0.07, P = 0.02, I² = 0). Both daytime (SMD = –0.22, 95% CI: –0.37 to –0.07, P = 0.005, I² = 74%) and night-time (SMD = –0.32, 95% CI: –0.61 to –0.02, P = 0.04, I² = 0) light exposure improved subjective alertness. The results of this meta-analysis and systematic review indicate that light exposure is associated with significant improvement in subjective and objective alertness. In addition, light exposure with a higher CCT was more effective in improving alertness than light exposure with a lower CCT. Our results also suggest that both daytime and night-time light exposure can improve subjective alertness.

Multiple positive outcomes of a later school starting time for adolescents

OBJECTIVE

We tested the effect of later school start time (LSST) by 1 hour during 1 week on sleep, sleepiness, and mood profile using within-subject design.

DESIGN

A within-subject 3-weeks-long interventional study. A baseline week with school starting at 7:30 AM (week A), followed by an intervention week with school starting at 8:30 AM (week B), and a recovery week with school start time back to 7:30 AM (week C). Mixed model for repeated measures analysis was applied to test for the LSST effect between weeks.

SETTING

A private high school with high level of socioeconomic status.

PARTICIPANTS

Forty-eight adolescents from 3 different high school years.

MEASUREMENTS

Participants were invited to wear actigraphs continuously during the 3 experimental weeks. Somnolence was obtained every school day twice, at arrival and before departure of school. Sleep quality and mood profile were evaluated by standard measures by the end of each school week, resulting in 3 repeated measures for each variable.

RESULTS

Thirty-eight adolescents completed the study. Adolescents woke up later during week B (7:42 ± 00:30) in comparison to weeks A (6:54 ± 00:12) and C (6:46 ± 00:15) (p < .001), with no significant change on sleep onset between weeks (p = .657), resulting in a longer sleep duration in week B (p < .001). Significant improvements on sleepiness and mood profile were also reported during week B.

CONCLUSIONS

Starting school later was effective in improving multiple aspects from sleep patterns, subjective sleepiness, and mood profile.

Trajectories, Risk Factors, and Impact of Persistent Pain After Major Musculoskeletal Surgery in Adolescents: A Replication Study

Studies have identified high rates of chronic postsurgical pain in adolescents. Characterizing patterns of pain in the transition from acute to chronic following major surgery may pinpoint critical periods of recovery. This observational study modelled pain trajectories over 1-year following surgery to attempt replication of prior work and evaluate baseline psychosocial factors and 12-month health outcomes. Adolescents 10 to 18 years completed electronic daily pain reporting for 7 days and self-reported health outcomes, at 5 assessment timepoints. Group-based trajectory modelling identified two trajectories with similar starting points in-hospital but distinct recovery courses at home. Pain declined steadily in one group across the study period ("Declining Pain"; estimated probability,18.9%), but pain increased after hospital discharge and remained high through 12-months in the other group ("High and Persistent Pain"; estimated probability,81.1%). Pre-surgery pain (Aor = 1.86, P = .001) and sleep quality (Aor = 0.49, P = .029) were associated with the High and Persistent pain trajectory in multivariate regressions. This trajectory was associated with lower total quality of life (B=-9.79, P = .002), physical health (B = -15.93, P < .001), psychosocial health (B = -6.73, P = .06), and greater fatigue (B = -13.61, P = .001). This study replicated prior findings identifying two post-surgical pain trajectories with diverging pain in the first two weeks. Clinical detection of those with increasing pain and early intervention may interrupt persistence of pain. PERSPECTIVE: This article replicates a prior study identifying distinct post-surgical pain trajectories, Declining Pain and High and Persistent Pain. The High and Persistent pain trajectory is associated with pre-surgery pain, pre-surgery sleep quality, and lower quality of life (total, physical, and psychosocial health as well as fatigue) at 12-month follow-up.

Positive Effects of Advanced Daylight Supply of Buildings on Schoolchildren—A Controlled, Single-Blinded, Longitudinal, Clinical Trial with Real Constructive Implementation

Sunlight controls endogen hormone balances and numerous health effects. Therefore, it is important to provide building users, such as schoolchildren, with sufficient daylight. Too much of it, however, leads to overheating, which is why shading systems are used. Consequently, these systems improve energy balance, but might not have positive effects on present people’s health. Within this study, shading systems were installed in classrooms of a middle school: common shading in two rooms, while two others were equipped with shading blades “Schlotterer RETROLux 80D” in an innovative design, reflecting more daylight indoors. The participating classes were divided between rooms with ordinary daylighting (n = 43) and advanced daylighting (n = 42). They spent, on average, 5 days weekly and 5–8 h daily in these classrooms. Saliva samples were collected during three semesters to detect hormonal changes. Questionnaires were collected to obtain more information about the mental alterations and, furthermore, to support the physiological results. A significant reduction in cortisol levels between 6:30 AM and 11:30 AM (p < 0.001) was observed within the group that had advanced daylighting. Questionnaires show that both groups sleep less as study duration increases (p < 0.001 time effect), but only the control group has a concurrent increase in daytime sleepiness according to relative treatment effects. The results show that increased daylight supply indoors leads to a significant greater reduction in cortisol levels of children and that those positive outcomes can be achieved by using innovative technologies for buildings.

Feinberg M. “A Little Bit Closer”: A Mixed Method Analysis of the Effect of the COVID-19 Pandemic on the Lives of Adolescent Parents

Using a Family Stress Model framework, we used quantitative and qualitative methods to investigate the impact of the pandemic on Latinx pregnant and parenting adolescents and their families. Participants were 406 adolescents (ages 14–19) in the southwestern U.S. who participated in a school-based relationship education program for pregnant and parenting adolescents. In the quantitative analysis, we compared self-reported mental health (depressive symptoms, worry, parental stress), coparental relationships (conflict and communication), and parenting of adolescents who participated prior to the pandemic ( N = 357; 83.6% female; 84.7% Latinx) with those who participated during the pandemic ( N = 49; 74.6% female; 87.8% Latinx). Unexpectedly, the pandemic-period cohort reported fewer depressive symptoms, less parental stress, more frequent coparental communication, and more positive coparental communication and conflict management than the pre-pandemic cohort. For the qualitative analysis, we conducted focus groups and individual interviews with 21 adolescent parents (95.2% female; 90.5% Latinx) from the pandemic-period cohort and analyzed the data using thematic analysis. Participants reported many negative effects of the pandemic including increased economic and health stress, yet also discussed reduced pressure with school and more time with family members. These findings have important implications for enhancing the well-being of adolescent parents and their children after the pandemic.

Teachers' preference for later school start times

Early morning school start times conflict with biologically determined sleep phase preference and thus contribute to common sleep deficits. This conflict is most pronounced in adolescents, and numerous studies have confirmed that later school start times are beneficial for their sleep and health. However, the conflict continues to exist beyond adolescence and, accordingly, also teachers might benefit from later school start times, but this has gained little attention so far. Importantly, teachers’ resistance to delay school start time is one of the key barriers for a successful implementation and, therefore, teachers’ school start time preferences and influencing factors are important to consider. To this end, we conducted an online survey. Teachers (n = 694, 56.1% female) from 17 high schools in Zurich, Switzerland, participated in the study. They indicated their school start time preference. In addition, four predictor blocks were assessed: sociodemographic, school‐/work‐related, and sleep characteristics, as well as teachers’ perception of students in the first morning lesson. Mixed models were applied to predict the preference. The majority (51%) endorsed later school start times (median preferred delay 25.2 min). School start time, sleep characteristics and perception of students in the first morning lesson were significant predictors for the preference. Thus, teachers with more misaligned sleep and higher awareness for students’ issues in the early morning were more likely to report a preference. This suggests psychoeducation about sleep biology throughout life span to be an effective measure to increase teachers’ support to delay school start time, especially because also they themselves are likely to benefit from later school start times.

School start times and academic achievement - A systematic review on grades and test scores

Early school times clash with the late sleep of adolescents, leading to wide-spread sleep restriction in students. Evidence suggests that delaying school starts is beneficial for sleep and recent studies investigated whether this also translates into improved academic achievement. We thus conducted a systematic review of the literature on school start times, grades and test scores in middle and high-school students. We reviewed 21 studies following the PRISMA guidelines and assessed the evidence quality using a pre-defined risk of bias tool. Nine studies reported no association of later starts with achievement, while the remaining reported mixed (5), positive (5), negative (1) or unclear (1) results. Considering the heterogeneity in academic outcomes, study types, amount of delay and exposure, and the substantial risk of bias, a meta-analysis was not warranted - instead we provide grouped reviews and discussion. Overall, no generalisable improvements in achievement with later starts emerge beyond the level of single studies. This does not necessarily preclude improvements in students' learning but highlights shortcomings of the literature and the challenges of using grades and test scores to operationalise academic achievement. Given other previously reported positive outcomes, our results suggest that schools could start later while achievement is likely maintained.

Classroom Activity Breaks Improve On-Task Behavior and Physical Activity Levels Regardless of Time of Day

Classroom physical activity breaks (CAB) are beneficial for increasing children's physical activity (PA) levels as well as the amount of time spent being on-task within the classroom. Purpose: To examine the effect of CAB at different times within the school day on on-task behavior and PA levels in primary school (grade 1-3) children. Methods: Thirty-five children (6 ± 1 y, 22 = male, 13 = female) participated in four conditions in a randomized order: morning (AM), afternoon (PM), morning and afternoon (BOTH), and no CAB (CTRL). CAB followed a traditional Tabata format of 20 s work and 10 s rest repeated 8 times for a total of 4 min. PA levels were monitored (accelerometry). On-task behavior and three types of off-task (motor, verbal, passive) were recorded following each CAB (mobile application). Results: When compared to control, AM, PM, and BOTH increased on-task behavior AM: Δ10.4%, PM: Δ10.5%, BOTH: Δ14%; p < .001). AM was most beneficial for reducing off-task motor (Δ-6.5%) and off-task verbal (Δ-3%) behavior, while PM was most beneficial for reducing off-task passive (Δ-9%) behavior. These effects were greatest in those students demonstrating higher amounts off-task behavior during CTRL (r > 0.67, p < .001). Students achieved an additional 8.4 (p = .070; d = 0.93), 12.2 (p < .001, d = 0.49), and 6.3 min (p = .09, d = 0.47) of moderate-vigorous physical activity (MVPA) over 24 h following a CAB vs CTRL in AM, PM, and BOTH, respectively. Additionally, performing any of the CAB conditions increased the number of steps taken during the school day by an average of 2007 steps (p < .009). Conclusion: Overall, these results demonstrate that CAB improve both on-task behavior and PA levels, regardless of time of day. However, performing two CAB (BOTH) is recommended to derive the greatest improvements in on-task behavior across the school day.

Associations between brain structure and sleep patterns across adolescent development

STUDY OBJECTIVES

Structural brain maturation and sleep are complex processes that exhibit significant changes over adolescence and are linked to many physical and mental health outcomes. We investigated whether sleep-gray matter relationships are developmentally invariant (i.e. stable across age) or developmentally specific (i.e. only present during discrete time windows) from late childhood through young adulthood.

METHODS

We constructed the Neuroimaging and Pediatric Sleep Databank from eight research studies conducted at the University of Pittsburgh (2009-2020). Participants completed a T1-weighted structural MRI scan (sMRI) and 5-7 days of wrist actigraphy to assess naturalistic sleep. The final analytic sample consisted of 225 participants without current psychiatric diagnoses (9-25 years). We extracted cortical thickness and subcortical volumes from sMRI. Sleep patterns (duration, timing, continuity, regularity) were estimated from wrist actigraphy. Using regularized regression, we examined cross-sectional associations between sMRI measures and sleep patterns, as well as the effects of age, sex, and their interaction with sMRI measures on sleep.

RESULTS

Shorter sleep duration, later sleep timing, and poorer sleep continuity were associated with thinner cortex and altered subcortical volumes in diverse brain regions across adolescence. In a discrete subset of regions (e.g. posterior cingulate), thinner cortex was associated with these sleep patterns from late childhood through early-to-mid adolescence but not in late adolescence and young adulthood.

CONCLUSIONS

In childhood and adolescence, developmentally invariant and developmentally specific associations exist between sleep patterns and gray matter structure, across brain regions linked to sensory, cognitive, and emotional processes. Sleep intervention during specific developmental periods could potentially promote healthier neurodevelopmental outcomes.

Bidirectional association between light exposure and sleep in adolescents

Sleep behaviour is controlled by both circadian and homeostatic influences. Changes in both factors are related to the delayed sleep timing observed in adolescence, which also generates restrictions in their sleep duration. In addition, the circadian factor explains part of the observed influence of light on sleep duration. We recorded 15 high-school students for 23 days (vacation: 11 days; school term: 12 days) using GENEactive accelerometers. We employed a repeated-measures analysis to explore the day-to-day bidirectional association between mean light exposure and sleep behaviour across a period with extreme variability in social pressures. Sleep onset was more than 30 min earlier and sleep duration almost 20 min longer when previous day light was 10 times more intense. Light intensity had a reduction of more than 20% as sleep ended 1 hr later. Besides, sleep onset and offset were both later during vacation than on school days (almost 2 hr and 4 hr, respectively) and free days (almost 1 hr, respectively). Therefore, sleep duration was almost 2 hr longer on vacation and free days than on school days. On the other hand, light exposure intensity was twice as high during vacation days when adjusted by sleep timing. Insufficient sleep duration is a major problem for adolescents. Although we found that light exposure was associated with longer sleep duration, the influence of school start times was greater and ended up prevailing, which explained the short sleep durations observed on school days.

Sleep trajectories from early adolescence to emerging adulthood: Evidence from a nine-year population-based study

INTRODUCTION

Adolescence to emerging adulthood is a developmental period when individuals experience substantial biological changes and social transitions. In East Asian societies, this period is also marked by high pressure around college entrance exams. However, little is known about how young people's sleep changes over time, or how it is impacted by social institutions in the cultural context. This study fills this gap in the literature by examining sleep trajectories from adolescence to emerging adulthood using a population-based, longitudinal sample from Taiwan.

METHODS

Multilevel models were applied to longitudinal data from the Taiwan Youth Project (N = 1,489) to estimate sleep trajectories from age 14 to 22 for total time in bed, bedtime, and wake-up time by gender and by educational pathway, controlling for family background.

RESULTS

Analysis revealed that Taiwanese youth sleep less as adolescents than as emerging adults. Gender differences exist in adolescents' sleep trajectories but narrow after age 18. Differences in weekday and weekend time in bed vary by gender and change as individuals emerge into adulthood. Finally, college attendees and high school only attendees display differences in sleep that begin in high school and continue through college.

CONCLUSIONS

The findings provide evidence of developmental changes in sleep from adolescence to emerging adulthood and demonstrate that sleep trajectories are gendered and socially patterned. The study is also one of the first to examine the sleep trajectories of East Asian youth and, as such, sheds light on the role of educational and cultural context as an influential factor.

Short sleep, insomnia symptoms, and evening chronotype are correlated with poorer mood and quality of life in adolescent transgender males

OBJECTIVE

Poor sleep is common among adolescents and associated with impaired mood and health-related quality of life (HRQOL). Transgender individuals are at increased risk of mood problems hypothesized to be due to minority stress; however, no research has investigated associations between sleep and mood in this population. We aimed to examine sleep, mood, and HRQOL in transgender adolescent males.

DESIGN & SETTING

Transgender males age 13-16 were recruited from a U.S. gender diversity clinic.

MEASUREMENTS

Participants completed one week of home actigraphy monitoring. Questionnaires assessed insomnia symptoms, chronotype, mood, and HRQOL. Pearson correlations between sleep, mood, and HRQOL were examined.

RESULTS

A total of 10 participants completed study measures during the school year. Participants obtained less than the recommended 8-10 hours of sleep per night, and half of participants endorsed insomnia symptoms. Greater insomnia symptoms were correlated with higher anxiety (P = .04) and depression (P = .04) symptoms, and poorer Psychosocial HRQOL (P = .03). Earlier weekday and weekend bed and wake times and earlier weekday sleep midpoint were associated with better Wellbeing HRQOL. No other significant correlations between sleep and mood or HRQOL variables were found.

CONCLUSIONS

Anxiety and depression symptoms were associated with self-reported insomnia symptoms, while HRQOL was associated with both insomnia symptoms and objective sleep timing in this sample of adolescent transgender males. Clinicians should assess both sleep and mood symptoms in this population and future research should evaluate the impact of improved sleep and gender-affirming care on mood and HRQOL for transgender adolescents.

Perceived daily sleep need and sleep debt in adolescents: associations with daily affect over school and vacation periods

STUDY OBJECTIVES

To describe trajectories of perceived daily sleep need and sleep debt, and examine if cumulative perceived sleep debt predicts next-day affect.

METHODS

Daily sleep and affect were measured over 2 school weeks and 2 vacation weeks (N=205, 54.1% females, M±SDage = 16.9±0.87 years). Each day, participants wore actigraphs and self-reported the amount of sleep needed to function well the next day (i.e., perceived sleep need), sleep duration, and high- and low-arousal positive and negative affect (PA, NA). Cumulative perceived sleep debt was calculated as the weighted average of the difference between perceived sleep need and sleep duration over the past 3 days. Cross-lagged, multilevel models were used to test cumulative sleep debt as a predictor of next-day affect. Lagged affect, day of the week, study day, and sociodemographics were controlled.

RESULTS

Perceived sleep need was lower early in the school week, before increasing in the second half of the week. Adolescents accumulated perceived sleep debt across school days and reduced it during weekends. On weekends and vacations, adolescents self-reported meeting their sleep need, sleeping the amount, or more than the amount of sleep they perceived as needing. Higher cumulative actigraphy sleep debt predicted higher next-day high arousal NA; higher cumulative diary sleep debt predicted higher NA (regardless of arousal), and lower low arousal PA the following day.

CONCLUSION

Adolescents experienced sustained, cumulative perceived sleep debt across school days. Weekends and vacations appeared to be opportunities for reducing sleep debt. Trajectories of sleep debt during vacation suggested recovery from school-related sleep restriction. Cumulative sleep debt was related to affect on a daily basis, highlighting the value of this measure for future research and interventions.

Lecture start time and sleep characteristics: Analysis of daily diaries of undergraduate students from the LoST-Sleep project

OBJECTIVES

Emerging evidence shows that later high school start times are associated with increased sleep duration; however, little is known if this extends to the university setting. This study investigated associations of first lecture start times with sleep characteristics among university students.

DESIGN

Daily diaries.

SETTING

Lincoln, UK.

PARTICIPANTS

One hundred and fifty-five undergraduate students completed 7-night sleep diaries MEASUREMENTS: Of the plausible lecture-day diaries (Monday-to-Friday, expected N = 755 days), 567 days were lecture days (M = 3.8 lecture-days per student, SD = 1.1). The Consensus Sleep Diary was used to collect sleep characteristics. Two-level multilevel mixed effect generalized linear models were employed in the analyses.

RESULTS

Seventy-five percent of first lectures occurred before noon. Students reported short sleep (M = 7.0 hours, SD = 1.9) and fewer reported highest levels of sleep quality (42.8%) and restfulness (24.8%) when first lectures started at 09:00 or 09:30 compared to 10:00 or later. Every hour delay of first lecture start time was associated with 15.1 (95% confidence interval [CI]: 9.5; 20.7) minutes increase in sleep duration and higher odds of reporting the highest levels of sleep quality and restfulness. Focusing on attended lectures starting before noon, hourly delay of first lecture start time was associated with 37.4 (95% CI: 22.0; 52.8) minutes increased sleep duration. Bedtime, sleep time, and sleep onset latency were not significantly associated with first lecture start times.

CONCLUSION

This study found that undergraduate students had longer sleep and healthier sleep quality when university first lectures started later. The earliest lecture start time that afforded sufficient sleep duration for students was 10:00.

Are Sweet Dreams Made of These? Understanding the Relationship Between Sleep and Cannabis Use

Introduction: There is widespread literature on the interaction between cannabis use and sleep, yet the mechanisms that underlie this relationship are not well understood. Several factors lead to inconsistencies in this relationship suggesting a nuanced interaction between cannabis and sleep. An important question that remains to be addressed is the temporal relationship between disrupted sleep and cannabis use. This literature review summarizes the existing literature on the association between disrupted sleep and cannabis toward the goal of addressing the question of the chronology of these reported effects. Materials and Methods: We conducted a review of the literature using PubMed to summarize current knowledge on the association between cannabis use and sleep in humans. Results: We identified 31 studies on the association of cannabis use and sleep. The findings from these studies were mixed. Cannabis was associated with a variety of impacts on sleep ranging from beneficial effects, such as reduced sleep-onset latency, to negative outcomes, such as reduced sleep duration and suppressed rapid eye movement oscillations. The chronology of the interaction of cannabis and sleep was unclear, although much of the current literature focus on factors that modulate how cannabis impairs sleep after initial use. Conclusion: There was sufficient evidence to suggest that cannabis use alters circadian rhythms, and hence, negatively impacts sleep. The current literature is largely from studies utilizing self-report measures of sleep; thus, objective measures of sleep are needed. In addition, although there were no empirical studies on the temporal relationship between cannabis use and sleep, the majority of the literature focused on characterizing sleep impairment after cannabis use.

Sleep Characteristics in the Italian Pediatric Population: A Systematic Review

OBJECTIVE

During childhood sleep duration, quality and patterns evolve and change greatly and relate strongly to healthy development. This systematic review aims to summarize the literature on sleep characteristics in the Italian pediatric population, adopting a cultural perspective.

METHOD

Pubmed, PsycINFO and Medline databases were systematically searched. Eligible studies had to: include Italian children and adolescents; report data for one or more sleep-related variables; be published in English or Italian.

RESULTS

Twenty-nine studies were selected including 18551 Italian children or adolescents. Studies were categorized by age group: infancy and toddlerhood (0-3 years); preschool and school age (3-12 years); adolescence (12-18 years) and mixed age groups. Overall, studies showed that the Italian pediatric population present shorter sleep duration and longer sleep onset latency compared to international recommendations. Furthermore, data indicate high prevalence of dysfunctional sleep habits, such as late bed-time (all age groups), involvement of parents during bed-time (infancy and toddlerhood), and high variability between sleep times on week-days vs. weekends (adolescence). Nevertheless, most studies lacked comprehensive data on sleep patterns, focusing instead on isolated variables.

CONCLUSION

These results suggest a strong trend among Italian children and adolescents towards unhealthy sleep patterns. Comprehensive data are still lacking and large studies evaluating a broad range of sleep characteristics in Italian pediatric populations are needed. Data strongly suggest that Italian Pediatric Primary Care should place higher focus on sleep problems and implement clinical protocols directed towards improving sleep patterns in children and adolescents.

Blunted rest-activity rhythms link to higher body mass index and inflammatory markers in children

STUDY OBJECTIVES

Disturbances of rest-activity rhythms are associated with higher body mass index (BMI) in adults. Whether such relationship exists in children is unclear. We aimed to examine cross-sectional associations of rest-activity rhythm characteristics with BMI z-score and obesity-related inflammatory markers in school-age children.

METHODS

Participants included 411 healthy children (mean ± SD age 10.1 ± 1.3 years, 50.8% girls) from a Mediterranean area of Spain who wore wrist accelerometers for 7 consecutive days. Metrics of rest-activity rhythm were derived using both parametric and nonparametric approaches. Obesity-related inflammatory markers were measured in saliva (n = 121).

RESULTS

In a multivariable-adjusted model, higher BMI z-score is associated with less robust 24-h rest-activity rhythms as represented by lower relative amplitude (-0.16 [95% CI -0.29, -0.02] per SD, p = 0.02). The association between BMI z-score and relative amplitude persisted with additional adjustment for sleep duration, and attenuated after adjustment for daytime activity level. Less robust rest-activity rhythms were related to increased levels of several salivary pro-inflammatory markers, including C-reactive protein, which is inversely associated with relative amplitude (-32.6% [-47.8%, -12.9%] per SD), independently of BMI z-score, sleep duration, and daytime activity level.

CONCLUSION

Blunted rest-activity rhythms are associated with higher BMI z-score and salivary pro-inflammatory markers already at an early age. The association with BMI z-score seem to be independent of sleep duration, and those with pro-inflammatory markers further independent of BMI z-score and daytime activity. Novel intervention targets at an early age based on improving the strength of rest-activity rhythms may help to prevent childhood obesity and related inflammation.

CLINICAL TRIALS REGISTRATION

NCT02895282.

A daily diary study of sleep chronotype among Mexican-origin adolescents and parents: Implications for adolescent behavioral health

The current study used daily assessments of sleep to examine stability and change in sleep chronotype in adolescents and their parents. The study assessed adolescent sleep chronotype according to age, gender, and parent chronotype, and evaluated its associations with emotional and behavioral problems in youth. Participants included of 417 Mexican American adolescents (Mage = 16.0 years, Range = 13.9-20.0) and 403 caregivers, who reported bed and wake times daily for 2 consecutive weeks at two time points spaced 1 year apart. In addition, adolescents completed established self-report questionnaires of emotional and behavioral problems. Chronotype was computed as the midsleep point from bed to wake time on free days, correcting for sleep debt accumulated across scheduled days. Multilevel modeling showed a curvilinear association between adolescent age and chronotype, with a peak eveningness observed between ages 16 to 17. Adolescent and parent chronotypes were contemporaneously correlated, but each was only moderately stable over the 1-year period. Later adolescent chronotype was contemporaneously associated with more substance use in all adolescents. Individual development and the family context shape sleep chronotype in adolescents and parents. Sleep chronotype is implicated in adolescent behavioral health.

COVID-19 and sleep patterns in adolescents and young adults

OBJECTIVE

In March 2020, the world experienced a global pandemic, which involved the shutdown of schools or a transposition to remote teaching in most countries. The objective of the present study was to investigate the impact of the COVID-19 pandemic related lockdown on sleep patterns and sleep quality in adolescents and young adults.

METHODS

An online survey was conducted in June 2020 with adolescents and young adults (n = 498) aged 12-25 years. Participants had to answer questions on sleep, first retrospectively, referring to the time prior to the pandemic, and then referring to the time during the pandemic.

RESULTS

A pronounced shift towards later sleep combined with an increase in sleep duration was found during the pandemic. However, these changes in sleep habits were more pronounced in adolescents than in young adults and seem to occur mostly during weekdays compared to weekends. During the pandemic, teens also reported an improvement in daytime sleepiness and subjective sleep quality, while young adults reported an increase in sleep difficulties associated with sleep onset difficulties, nocturnal and early morning awakenings, and nightmares.

CONCLUSIONS

The COVID-19 related lockdown seems to have had a beneficial effect on sleep in adolescents. In young adults, benefits are not as obvious. These results support that later school start times would be beneficial for adolescents. However, in young adults it could be important to investigate the effects of other situational or interindividual factors (stress, lifestyle habits, employment, etc.).

Sleepiness, sleep deprivation, quality of life, mental symptoms and perception of academic environment in medical students

BACKGROUND

It has been previously shown that a high percentage of medical students have sleep problems that interfere with academic performance and mental health.

METHODS

To study the impact of sleep quality, daytime somnolence, and sleep deprivation on medical students, we analyzed data from a multicenter study with medical students in Brazil (22 medical schools, 1350 randomized medical students). We applied questionnaires of daytime sleepiness, quality of sleep, quality of life, anxiety and depression symptoms and perception of educational environment.

RESULTS

37.8% of medical students presented mild values of daytime sleepiness (Epworth Sleepiness Scale - ESS) and 8.7% presented moderate/severe values. The percentage of female medical students that presented ESS values high or very high was significantly greater than male medical students (p <  0.05). Students with lower ESS scores presented significantly greater scores of quality of life and perception of educational environment and lower scores of depression and anxiety symptoms, and these relationships showed a dose-effect pattern. Medical students reporting more sleep deprivation showed significantly greater odds ratios of presenting anxiety and depression symptoms and lower odds of good quality of life or perception of educational environment.

CONCLUSIONS

There is a significant association between sleep deprivation and daytime sleepiness with the perception of quality of life and educational environment in medical students.

The longitudinal relationship between sleep problems and school burnout in adolescents: A cross-lagged panel analysis

INTRODUCTION

Despite the growing body of cross-sectional research linking sleep problems and school burnout, hardly any research has investigated the longitudinal relationship between these two constructs. The aim of this study was to examine the bidirectional association between sleep problems and school burnout in middle school students.

METHODS

A prospective design was used incorporating four time points (approximately 6-month interval). The participants were 1226 (50.3% girls) middle school students from 4 public schools who were in 7th grade at baseline. On average, participants were approximately 12.5 years old at the beginning of the study (M_age = 12.73, SD = 0.68). All participants completed self-report measures in classrooms during regular school hours. The data were analyzed using a cross-lagged structural equation model. We also examined the stability of sleep problems and school burnout in time, and investigated the moderating role of gender.

RESULTS

The results indicated there is a moderate stability for both sleep problems and school burnout, and those students with sleep problems were more likely to develop school burnout, and vice versa. Gender did not moderate the bidirectional relationship.

CONCLUSIONS

These results suggest that future studies should investigate whether implementing intervention for sleep problems can decrease the occurrence of school burnout and whether interventions targeting school burnout can improve sleep problems.

Association between physical activity, screen time activities, diet patterns and daytime sleepiness in a sample of Brazilian adolescents

OBJECTIVE

To examine the association between physical activity, screen time, eating habits and daytime sleepiness among Brazilian adolescents.

METHODS

Adolescents from three high schools (n = 876, 49.8% female, 16.4 ± 1.2 years) participated in this cross-sectional survey. Variables related to lifestyle behaviors (ie, physical activity, screen time, eating habits, sleep duration) were collected through an online questionnaire. Daytime sleepiness was assessed using the Pediatric Daytime Sleepiness Scale (PDSS). Excessive daytime sleepiness was defined as a PDSS score ≥20.

RESULTS

The average PDSS score was 18.9 (SD ± 4.8) points and 46.8% of adolescents were classified as having excessive daytime sleepiness. Physical activity was inversely associated with PDSS score (β = -0.29, 95% CI -0.47; -0.11). Consuming processed foods frequently (β = 1.16, 95% CI 0.85; 1.47) and using social media (β = 0.22, 95% CI 0.14; 0.30) were positively associated with PDSS score. Similar findings were observed for the odds of excessive daytime sleepiness. Physical activity was inversely associated (OR = 0.91, 95% CI 0.84; 0.99), while frequent consumption of processed foods (OR = 1.55, 95% CI 1.33; 1.82) and using social media (OR = 1.13, 95% CI 1.02; 1.24) were positively associated with excessive daytime sleepiness.

CONCLUSIONS

Lower physical activity level, a higher consumption processed foods, and higher social media use were associated with daytime sleepiness in this sample of Brazilian adolescents.

Caloric and Macronutrient Intake and Meal Timing Responses to Repeated Sleep Restriction Exposures Separated by Varying Intervening Recovery Nights in Healthy Adults

Sleep restriction (SR) reliably increases caloric intake. It remains unknown whether such intake cumulatively increases with repeated SR exposures and is impacted by the number of intervening recovery sleep opportunities. Healthy adults (33.9 ± 8.9y; 17 women, Body Mass Index: 24.8 ± 3.6) participated in a laboratory protocol. N = 35 participants experienced two baseline nights (10 h time-in-bed (TIB)/night; 22:00–08:00) followed by 10 SR nights (4 h TIB/night; 04:00–08:00), which were divided into two exposures of five nights each and separated by one (n = 13), three (n = 12), or five (n = 10) recovery nights (12 h TIB/night; 22:00–10:00). Control participants (n = 10) were permitted 10 h TIB (22:00–08:00) on all nights. Food and drink consumption were ad libitum and recorded daily. Compared to baseline, sleep-restricted participants increased daily caloric (+527 kcal) and saturated fat (+7 g) intake and decreased protein (−1.2% kcal) intake during both SR exposures; however, intake did not differ between exposures or recovery conditions. Similarly, although sleep-restricted participants exhibited substantial late-night caloric intake (671 kcal), such intake did not differ between exposures or recovery conditions. By contrast, control participants showed no changes in caloric intake across days. We found consistent caloric and macronutrient intake increases during two SR exposures despite varying intervening recovery nights. Thus, energy intake outcomes do not cumulatively increase with repeated restriction and are unaffected by recovery opportunities.

Sleep in Myopic and Non-Myopic Children

Purpose

To examine differences in sleep between myopic and non-myopic children.

Methods

Objective measurements of sleep, light exposure, and physical activity were collected from 91 children, aged 10 to 15 years, for two 14-day periods approximately 6 months apart. Sleep parameters were analyzed with respect to refractive error, season, day of the week, age, and sex.

Results

Myopic children exhibited differences in sleep duration by day of the week (P < 0.001) and season (P = 0.007). Additionally, myopic children exhibited shorter sleep latency than non-myopic children (P = 0.04). For all children, wake time was later (P < 0.001) and sleep duration was longer (P = 0.03) during the cooler season compared with the warmer season. On weekends, children went to bed later (P < 0.001), woke up later (P < 0.001), and had increased sleep duration (P < 0.001) than on weekdays. Younger children exhibited earlier bedtime (P = 0.005) and wake time (P = 0.01) than older children. Time spent outdoors was positively associated with sleep duration (P = 0.03), and daily physical activity was negatively associated with wake time (P < 0.001).

Conclusions

Myopic children tended to have more variable sleep duration and shorter latency than non-myopic children. Sleep patterns were influenced by season, day of the week, age, time outdoors, and activity.

Translational Relevance

Myopic children tended to have more variable sleep duration and shorter latency than non-myopic children, which may reflect previously reported differences in environmental and behavioral factors between refractive error groups.

Short Sleep Duration and Extremely Delayed Chronotypes in Uruguayan Youth: The Role of School Start Times and Social Constraints

During adolescence, biological, psychosocial, and contextual factors converge in a “perfect storm” and have been put forward to explain the delay in chronotype observed at this age and the prevalence of disrupted sleep. This study provides evidence to support that chronotype and sleep patterns (particularly sleep duration) are socially constrained and to identify novel significant social predictors. Uruguayan public school activities are arranged in up to 4 shifts, creating a natural experiment to examine the effect of school timing on questionnaire-based assessments of sleep and chronotype. In this study, 268 high school students (15-18 years old) who attended school either on morning (0730 to 1130 h) or afternoon shifts (1130 h to 1530 h) responded to an adapted School Sleep Habits Survey. Students attending afternoon shifts had later chronotypes (a 1.5-h later midpoint of sleep on free days adjusted for sleep debt) than those attending the morning shift. Besides shift, evening social activities (including dinner time) were further identified as key predictors of late chronotypes, whereas age and gender were not. Sleep on school days was overall advanced and reduced with respect to weekends, and these effects were stronger in morning-shift students. Weekend sleep duration was similar between shifts, which probably caused the prevalence of reduced sleep durations (average weekly sleep duration, SDweek <8 h) to be higher in morning-shift students (almost 80%) than in afternoon-shift ones (34%). Reduced sleep duration was significantly higher in morning-shift students. In addition, age, chronotype, and dinner time became relevant determinants of sleep deficit only in the morning-shift students. Besides the important social constraint of early school start time, this is the first study to confirm the significance of other types of social pressures on both adolescents’ chronotype and sleep deficit, which can be useful as potential new targets for effective policies to protect adolescent sleep.

Poor Sleep Is Related to Metabolic Syndrome Severity in Adolescents With PCOS and Obesity

CONTEXT

Polycystic ovary syndrome (PCOS) is a common endocrine disorder and is associated with metabolic syndrome (MS). Development of MS in PCOS is likely multifactorial and may relate to poor sleep.

OBJECTIVE

The objective of this research is to investigate differences in objective markers of sleep in adolescents with obesity and PCOS with and without MS. We also aimed to examine the relationships between markers of sleep with MS markers.

DESIGN

A cross-sectional study was conducted.

PARTICIPANTS

Participants included adolescents with PCOS and obesity with MS (N = 30) or without MS (N = 36).

OUTCOME MEASURES

Hormone and metabolic measurements, abdominal magnetic resonance imaging for hepatic fat fraction, actigraphy to estimate sleep, and overnight polysomnography (PSG).

RESULTS

Adolescents with obesity and PCOS who also had MS had significantly worse sleep-disordered breathing including higher apnea-hypopnea index (AHI, P = .02) and arousal index (P = .01) compared to those without MS. Actigraphy showed no differences in habitual patterns of sleep behaviors including duration, timing, or efficiency between groups. However, a greater number of poor sleep health behaviors was associated with greater number of MS components (P = .04). Higher AHI correlated with higher triglycerides (TG) (r = 0.49, P = .02), and poorer sleep efficiency correlated with higher percentage of liver fat (r = -0.40, P = .01), waist circumference (r = -0.46, P < .01) and higher TG (r = -0.34, P = .04).

CONCLUSIONS

Among girls with PCOS and obesity, sleep-disordered breathing was more prevalent in those with MS, and poor sleep behaviors were associated with metabolic dysfunction and more MS symptoms. Sleep health should be included in the assessment of adolescents with PCOS and obesity.

Association of Sunlight Exposure with Sleep Hours in Iranian Children and Adolescents: The CASPIAN-V Study

We aimed to assess the association of sunlight exposure with sleep duration and sleep onset time in children. Data were obtained from the fifth survey of a national school-based surveillance program in Iran. Sunlight exposure time, sleep duration, sleep onset time, physical activity time, mental health status and frequency of consuming coffee and tea were recorded. Overall, 14 274 students aged 7-18 years were recruited. Sleep duration was associated positively with sex, age, body mass index and physical activity, as well as with sunlight exposure and negatively with the consumption of coffee and tea. Higher physical activity, exposure to sunlight and mental status score in children exposed to sunlight via their face, hands, arms and feet, reduced the likelihood of sleep onset time after midnight (odds ratio (OR) = 0.909, 0.741 and 0.554 respectively). Daily exposure to sunlight may increase sleep duration and advance the sleep onset time in children and adolescents.

The Moderating Role of Sleep in the Relationship Between Social Isolation and Internalising Problems in Early Adolescence

Social isolation may be a unique risk factor for depression and anxiety in early adolescence. However, optimal sleep may protect adolescents from the emotional sequela of social isolation. The present study aimed to investigate whether sleep moderates the relationship between social isolation and symptoms of anxiety and depression in early adolescence. Five hundred and twenty eight early adolescents (M = 11.18 years, SD = 0.56, range 10-12 years, 51% male) completed online questionnaires assessing social isolation, sleep duration, daytime sleepiness and symptoms of generalised anxiety, social anxiety, separation anxiety and depression. Sleep duration moderated the effect of social isolation on symptoms of generalised anxiety, social anxiety and depression, but not separation anxiety. Daytime sleepiness emerged as an additional sleep-related risk factor in the relationship between social isolation and depressive symptoms. Therefore, sleep may be an important modifiable risk or protective factor to target, in the prevention of depression and anxiety in adolescence.

Naturalistic, multimethod exploratory study of sleep duration and quality as predictors of dysregulated eating in youth with overweight and obesity

Although poor sleep has been found to adversely impact eating and weight regulation in youth, past research is limited by retrospective reporting and/or non-naturalistic designs. We investigated the feasibility of combining three momentary, ecologically valid approaches to assessing sleep and eating behavior, and associations between these constructs, among youth (aged 8-14y) with overweight/obesity (n = 40). Participants completed 14 overlapping days of actigraphy assessment and smartphone-based ecological momentary assessment (EMA) of eating behavior, of which 3 days also included computerized, self-guided 24-h dietary recall. Feasibility of completing measures concurrently was evaluated by generating frequencies of compliance. Associations between sleep indices and next-day eating behavior were examined via generalized estimating equations. Of 29 participants who provided EMA and 24-h recall data that aligned with previous night actigraphy data, both EMA and sleep data were available on an average of 8.6 out of 14 possible days, and both 24-h recall and sleep data on an average of 2.7 out of 3 possible days. Each additional hour of sleep was associated with consuming fewer calories from solid fats, alcohol, and added sugars (b = 0.70; p = .04). Combining naturalistic, momentary assessments of sleep and eating behavior appears to be acceptable in youth. Larger experimental studies are needed to further understand associations between sleep parameters and eating behavior.

Chronotype, Social Jet Lag, and Cardiometabolic Risk Factors in Early Adolescence

IMPORTANCE

Inadequate sleep duration and quality increase the risk of obesity. Sleep timing, while less studied, is important in adolescents because increasing evening preferences (chronotypes), early school start times, and irregular sleep schedules may cause circadian misalignment.

OBJECTIVE

To investigate associations of chronotype and social jet lag with adiposity and cardiometabolic risk in young adolescents.

DESIGN, SETTING, AND PARTICIPANTS

Starting in 1999, Project Viva recruited pregnant women from eastern Massachusetts. Mother-child in-person visits occurred throughout childhood. From January 23, 2012, to October 16, 2016, 804 adolescents aged 12 to 17 years completed 5 days or more of wrist actigraphy, questionnaires, and anthropometric measurements. A cross-sectional analysis using these data was conducted from April 31, 2018, to May 1, 2019.

EXPOSURES

Chronotype, measured via a continuous scale with higher scores indicating greater evening preferences, and social jet lag, measured as the continuous difference in actigraphy sleep midpoint in hours from midnight on weekends vs weekdays, with higher values representing more delayed sleep timing on weekends.

MAIN OUTCOMES AND MEASURES

Adiposity, measured via anthropometry and dual-energy x-ray absorptiometry. For a subset of 479 adolescents with blood samples, cardiometabolic risk scores were computed as the mean of 5 sex- and cohort-specific z scores for waist circumference, systolic blood pressure, inversely scaled high-density lipoprotein cholesterol, and log-transformed triglycerides and homeostatic model of insulin resistance.

RESULTS

Among the 804 adolescents in the study, 418 were girls and 386 were boys, with a mean (SD) age of 13.2 (0.9) years. In multivariable models adjusted for age, puberty, season, and sociodemographics, associations of chronotype and social jet lag with adiposity varied by sex. For girls, greater evening preference was associated with a 0.58-cm (95% CI, 0.12-1.03 cm; P = .04 for interaction) higher waist circumference and 0.16 kg/m2 (95% CI, 0.01-0.31 kg/m2; P = .03 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry; each hour of social jet lag was associated with a 1.19-cm (95% CI, 0.04-2.35 cm; P = .21 for interaction) higher waist circumference and 0.45 kg/m2 (95% CI, 0.09-0.82 kg/m2; P = .01 for interaction) higher fat mass index as measured by dual-energy x-ray absorptiometry. Associations of social jet lag and evening chronotypes persisted for many measures of adiposity after adjustment for sleep duration and other lifestyle behaviors. By contrast, no associations were observed in boys. There were no associations with the cardiometabolic risk score for either sex, although statistical power was low for this outcome.

CONCLUSIONS AND RELEVANCE

Evening chronotypes and social jet lag were associated with greater adiposity in adolescent girls but not adolescent boys. Interventions aimed at improving sleep schedules may be useful for obesity prevention, especially in girls.

Effect of Light Flashes vs Sham Therapy During Sleep With Adjunct Cognitive Behavioral Therapy on Sleep Quality Among Adolescents: A Randomized Clinical Trial

IMPORTANCE

Owing to biological, behavioral, and societal factors, sleep duration in teenagers is often severely truncated, leading to pervasive sleep deprivation.

OBJECTIVE

To determine whether a novel intervention, using both light exposure during sleep and cognitive behavioral therapy (CBT), would increase total sleep time in teenagers by enabling them to go to sleep earlier than usual.

DESIGN, SETTING, AND PARTICIPANTS

This double-blind, placebo-controlled, randomized clinical trial, conducted between November 1, 2013, and May 31, 2016, among 102 adolescents enrolled full-time in grades 9 to 12, who expressed difficulty going to bed earlier and waking up early enough, was composed of 2 phases. In phase 1, participants were assigned to receive either 3 weeks of light or sham therapy and were asked to try to go to sleep earlier. In phase 2, participants received 4 brief CBT sessions in addition to a modified light or sham therapy. All analyses were performed on an intent-to-treat basis.

INTERVENTIONS

Light therapy consisted of receiving a 3-millisecond light flash every 20 seconds during the final 3 hours of sleep (phase 1) or final 2 hours of sleep (phase 2). Sham therapy used an identical device, but delivered 1 minute of light pulses (appearing in 20-second intervals, for a total of 3 pulses) per hour during the final 3 hours of sleep (phase 1) or 2 hours of sleep (phase 2). Light therapy occurred every night during the 4-week intervention. Cognitive behavioral therapy consisted of four 50-minute in-person sessions once per week.

MAIN OUTCOMES AND MEASURES

Primary outcome measures included diary-based sleep times, momentary ratings of evening sleepiness, and subjective measures of sleepiness and sleep quality.

RESULTS

Among the 102 participants (54 female [52.9%]; mean [SD] age, 15.6 [1.1] years), 72 were enrolled in phase 1 and 30 were enrolled in phase 2. Mixed-effects models revealed that light therapy alone was inadequate in changing the timing of sleep. However, compared with sham therapy plus CBT alone, light therapy plus CBT significantly moved sleep onset a mean (SD) of 50.1 (27.5) minutes earlier and increased nightly total sleep time by a mean (SD) of 43.3 (35.0) minutes. Light therapy plus CBT also resulted in a 7-fold greater increase in bedtime compliance than that observed among participants receiving sham plus CBT (mean [SD], 2.21 [3.91] vs 0.29 [0.76]), as well as a mean 0.55-point increase in subjective evening sleepiness as compared with a mean 0.48-point decrease in participants receiving sham plus CBT as measured on a 7-point sleepiness scale.

CONCLUSIONS AND RELEVANCE

This study found that light exposure during sleep, in combination with a brief, motivation-focused CBT intervention, was able to consistently move bedtimes earlier and increase total sleep time in teenagers. This type of passive light intervention in teenagers may lead to novel therapeutic applications.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01406691.

School start times and teenage driver motor vehicle crashes

INTRODUCTION

Shifting school start times to 8:30 am or later has been found to improve academic performance and reduce behavior problems. Limited research suggests this may also reduce adolescent driver motor vehicle crashes. A change in the school start time from 7:30 am to 8:45 am for all public high schools in one North Carolina county presented the opportunity to address this question with greater methodologic rigor.

METHOD

We conducted ARIMA interrupted time-series analyses to examine motor vehicle crash rates of high school age drivers in the intervention county and 3 similar comparison counties with comparable urban-rural population distribution. To focus on crashes most likely to be affected, we limited analysis to crashes involving 16- & 17-year-old drivers occurring on days when school was in session.

RESULTS

In the intervention county, there was a 14% downward shift in the time-series following the 75 min delay in school start times (p = .076). There was no change approaching statistical significance in any of the other three counties. Further analysis indicated marked, statistically significant shifts in hourly crash rates in the intervention county, reflecting effects of the change in school start time on young driver exposure. Crashes from 7 to 7:59 am decreased sharply (-25%, p = .008), but increased similarly from 8 to 8:59 am (21%, p = .004). Crashes from 2 to 2:59 pm declined dramatically (-48%, p = .000), then increased to a lesser degree from 3 to 3:59 pm (32%, p = .024) and non-significantly from 4 to 4:59 (19%, p = .102). There was no meaningful change in early morning or nighttime crashes, when drowsiness-induced crashes might have been expected to be most common.

DISCUSSION

The small decrease in crashes among high school age drivers following the shift in school start time is consistent with the findings of other studies of teen driver crashes and school start times. All these studies, including the present one, have limitations, but the similar findings suggest that crashes and school start times are indeed related, with earlier start times equating to more crashes.

CONCLUSION

Later high school start times (>8:30 am) appear to be associated with lower adolescent driver crash rates, but additional research is needed to confirm this and to identify the mechanism by which this occurs (reduced drowsiness or reduced exposure).

Circadian misalignment and weekend alcohol use in late adolescent drinkers: preliminary evidence

Alcohol use accelerates during late adolescence, predicting the development of alcohol use disorders (AUDs) and other negative outcomes. Identifying modifiable risk factors for alcohol use during this time could lead to novel prevention approaches. Burgeoning evidence suggests that sleep and circadian factors are cross-sectionally and longitudinally linked to alcohol use and problems, but more proximal relationships have been understudied. Circadian misalignment, in particular, is hypothesized to increase the risk for AUDs, but almost no published studies have included a biological measure of misalignment. In the present study, we aimed to extend existing research by assessing the relationship between adolescent circadian misalignment and alcohol use on a proximal timeframe (over two weeks) and by including three complementary measures of circadian alignment. We studied 36 healthy late (18-22 years old, 22 females) alcohol drinkers (reporting ≥1, standard drink per week over the past 30 days) over 14 days. Throughout the study, participants reported prior day's alcohol use and prior night's sleep each morning via smartphone and a secure, browser-based interface. Circadian phase was assessed via the dim light melatonin onset (DLMO) in the laboratory on two occasions (Thursday and Sunday nights) in counterbalanced order. The three measures of circadian alignment included DLMO-midsleep interval, "classic" social jet lag (weekday-weekend difference in midsleep), and "objective" social jet lag (weekday-weekend difference in DLMO). Multivariate imputation by chained equations was used to impute missing data, and Poisson regression models were used to assess associations between circadian alignment variables and weekend alcohol use. Covariates included sex, age, Thursday alcohol use, and Thursday sleep characteristics. As predicted, greater misalignment was associated with greater weekend alcohol use for two of the three alignment measures (shorter DLMO-midsleep intervals and larger weekday-weekend differences in midsleep), while larger weekday-weekend differences in DLMO were associated with less alcohol use. Notably, in contrast to expectations, the distribution of weekday-weekend differences in DLMO was nearly equally distributed between individuals advancing over the weekend and those delaying over the weekend. This unexpected finding plausibly reflects the fact that college students are not subject to the same systematically earlier weekday schedules observed in high school students and working adults. These preliminary findings support the need for larger, more definitive studies investigating the proximal relationships between circadian alignment and alcohol use among late adolescents.