Midpoint Of Sleep Research Articles

Association of delayed chronotype with allergic diseases in primary school children

ABSTRACT To investigate the associations of sleep midpoint for both weekdays and weekends, and chronotype, with allergic diseases, specifically asthma, allergic rhinitis, and eczema in primary school children. In this cross-sectional study, we evaluated 10409 children between 7 and 12 years of age (mean 9.21 ± 1.51 years; male 52.2%). Each allergic disease was defined as children with both diagnosed disease and current symptoms, and the reference group was described as children without any allergic symptoms. Sleep durations and mid-sleep times were calculated by reported sleep timing. Chronotype was determined by mid-sleep time on free days corrected for oversleeping. Children with allergies have shorter sleep duration and later sleep preferences. Late weekly sleep midpoints were associated with higher odds of allergies, and the odds were even higher for later weekday midpoints than their weekend counterparts. Regarding chronotype, the more evening chronotype, the higher the odds of allergic rhinitis and eczema. Additionally, effect of weekday late sleep midpoint on allergies was stronger as the participants who slept less (asthma: aOR,1.62, 95 CI%,1.25–2.10, p < .001; allergic rhinitis: aOR,2.12, 95 CI%,1.68–2.67, p < .001; eczema: aOR, 1.94, 95 CI%,1.52–2.48, p < .001). Further, the associations of chronotype with allergic rhinitis were confounded by second-hand smoking exposure. Our study, which finds an association between chronotype and the odds of three allergic diseases, hopes to improve sleep health awareness, especially in the particular population with allergic diseases, and describes the importance of evaluating modifiable behavioral factors, such as sleep habits, as a plausible factor for the prevention and treatment of allergic diseases.

On workdays, earlier sleep for morningness and later wakeup for eveningness are associated with better work productivity

IntroductionMisalignment of chronotype and social schedules result in sleep and health impairments. Presenteeism, the work productivity loss caused by health problems, has much more social costs than absenteeism and is associated with sleep disturbance. However, little is known about the link between chronotype and presenteeism. In this study, the associations between chronotype, sleep schedules, presenteeism, and the mediating role of sleep disturbance were examined. MethodsA cross-sectional survey was conducted on 8155 office workers from 42 companies in Japan, from 2017 to 2019. The participants answered self-administered questionnaires asking about presenteeism (Work Limitations Questionnaire [WLQ]), sleep disturbance (Pittsburgh Sleep Quality Index [PSQI]), and habitual sleep schedules which enable to calculate the midpoint of sleep on free days, sleep corrected (MSFsc). The mediating effect was examined by using structural equation modeling (SEM). ResultsThe participants comprised 4462 males and 3677 females (mean age: 36.7 years), and their mean productivity loss was 5.97%. A later sleep onset (+0.29%/h), early wakeup (+0.14%/h), and eveningness (+0.27%/h, MSFsc) were associated with presenteeism in all participants; however, the effect size and significance differed depending on their chronotype. SEM demonstrated a complete mediation model between chronotype and presenteeism, mediated by sleep disturbance and adjusted by age. ConclusionsChronotype did not directly, but indirectly affected presenteeism through sleep disturbance. Eveningness leads to sleep disturbance, which then causes presenteeism. On workdays, early sleep times for morningness people, and late wakeup times for eveningness people may improve their work productivity.

Validity of chronotype questionnaires in adolescents: Correlations with actigraphy.

There are only a few validated chronotype and morningness-eveningness questionnaires for adolescents. We evaluated three such questionnaires, namely Morningness-Eveningness Stability Scale improved; reduced Morningness-Eveningness Questionnaire for Children and Adolescents; and Composite Scale of Morningness in adolescents against actigraphy. Fifty-fivehealthy 13- to 16-year-old adolescents completed the Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, Composite Scale of Morningness, and Pediatric Daytime Sleepiness Scale, and provided a 7-day actigraphy and sleep diary recording about their sleep-wake patterns. We examined the correlations between sleep-wake and activity parameters, and the questionnaires. The influence of age and sex on chronotype classification was studied using uni- and multivariate analyses. All three chronotype questionnaires showed good internal consistency and convergent validity. Spearman correlations reflected less daytime sleepiness, earlier sleep times, midpoints of sleep, and acrophase in morning-oriented participants. Evening-oriented participants had more sleepiness and later respective sleep-wake times. Chronotype classification differed significantly between questionnaires. The Composite Scale of Morningness classified more participants as morning types when compared with the reduced Morningness-Eveningness Questionnaire for Children and Adolescents (12 versus 7, respectively), and fewer adolescents as evening types (5 versus 9, respectively). Age and sex had no significant influence on questionnaire scores. The Morningness-Eveningness Stability Scale improved, reduced Morningness-Eveningness Questionnaire for Children and Adolescents, and Composite Scale of Morningness are valid instruments to determine circadian preference in adolescents; however, chronotype classification from the Composite Scale of Morningness and reduced Morningness-Eveningness Questionnaire for Children and Adolescents cannot be used interchangeably.

Abstract MP56: Sleep Regularity Modifies The Association Of Visceral Adiposity With Elevated Blood Pressure In Adolescents

Introduction: Although obesity, insufficient sleep and sleep apnea are known risk factors for elevated blood pressure, the circadian timing of sleep is also involved in metabolic and blood pressure regulation. As a result, sleep irregularity, which is highly prevalent in adolescents, may be a potential risk factor for obesity-related adverse cardiovascular outcomes. Hypothesis: We hypothesize that greater sleep irregularity increases the impact of visceral adiposity on elevated blood pressure in adolescents. Methods: We analyzed cross-sectional data from the Penn State Child Cohort follow-up study, a random population-based sample of 303 adolescents (16.2 ± 2.2 year old; 47.5% female; 21.5% racial/ethnic minority) who had complete at-home 7-night (at least 5) actigraphy (ACT) data and in-lab dual-energy X-ray absorptiometry (DEXA) scan and polysomnography (PSG) data. ACT-measured sleep duration and sleep midpoint were calculated as the intra-individual mean of the 7-night total sleep time and the midpoint (zeroed to midnight) of the sleep period, respectively. ACT-measured sleep regularity was calculated as the intra-individual standard deviation of the 7-night sleep midpoint. DEXA-measured visceral adipose tissue (VAT) was the primary predictor. Systolic (SBP) and diastolic (DBP) blood pressure, measured three times in the seated position, were the primary outcomes. Multivariable linear regression models tested sleep midpoint and sleep regularity as effect modifiers of VAT on SBP/DBP levels, while simultaneously adjusting for sex, race/ethnicity, age, ACT-measured sleep duration and PSG-measured apnea/hypopnea index. Results: Significant interactions were found between sleep regularity and VAT on SBP (p-interaction=0.009) and DBP (p-interaction=0.039), while not between mean sleep midpoint and VAT (p-interactions=0.210 and 0.883). These findings remained valid even after further adjusting for body mass index percentile (p-interactions=0.006 and 0.034). Among adolescents with high sleep irregularity (≥ 45 minutes; n=124), each standard deviation increase in VAT was associated with a 5.55 (0.91) and 3.07 (0.70) mmHg increase in SBP and DBP, respectively (both p&lt;0.001). Among those with low sleep irregularity (&lt; 45 minutes; n=179) VAT was not significantly associated with SBP [0.69 (0.99), p=0.488] or DBP [0.04 (0.77), p=0.956]. Conclusions: An irregular circadian timing of sleep may increase the impact of visceral adiposity on elevated blood pressure in adolescents. These data support that sleep irregularity, independent of sleep apnea and insufficient sleep, may contribute to the development of cardiovascular sequelae associated with central obesity.

Morningness-eveningness preference and shift in chronotype during COVID-19 as predictors of mood and well-being in university students

It is suggested that social obligations, such as early work/school starts, have a disadvantageous impact on sleep behavior that can further transfer to mental health problems. Lockdown as a result of the COVID-19 pandemic created a unique opportunity to research human sleep-wake behavior in naturalistic conditions of decreased social obligations. This study aimed to test whether a change in habitual sleep-wake timing (shift in chronotype) during the COVID-19 lockdown impacted mood and well-being, and whether the impact differs according to morningness-eveningness preference. University students (N = 1011; Meanage = 21.95 ± 1.95 years) filled out self-report questionnaires containing measures of chronotype (midpoint of sleep) before and during the COVID-19 lockdown, morningness-eveningness preference, mood, and well-being. The impact of morningness-eveningness preference and shift in chronotype was tested via multiple regression analyses. Results showed that participants shifted their chronotype in line with their morningness-eveningness preference, and that shift toward earlier sleep-wake timing was related to better moods and well-being. Moreover, higher levels of positive mood (vigor) and well-being were found in individuals who shifted their sleep-wake timing earlier and were higher on morningness.

Match or mismatch between chronotype and sleep-wake cycle and their association with lean body mass gain among male high-school baseball players

ABSTRACT For athletes, it is important to acquire lean body mass (LBM) involving the skeletal muscle mass during their growth periods; however, the influence of chronotype on LBM gain remains unclear. We therefore aimed to investigate whether chronotype, sleep-wake cycle on weekdays (SWC-W), and their interaction contribute to LBM gain among adolescent male athletes in a 4-month intervention study. The participants were 45 male high-school baseball players. The intervention, including exercise menu (running and muscle strength training) and nutritional education, was conducted during a 4-month period of season-off training. The chronotype, body composition, lifestyle, and dietary intake were investigated before intervention (baseline) and after 4 months. Among the participants [Morningness (n = 14), Eveningness (n = 15), Intermediate (n = 16); ME score based on the Morningness/Eveningness Scale for Children (MES-C)], the midpoint of sleep on weekdays (MSW) was calculated in the “Morningness” and “Eveningness” participants, respectively. They were divided into 4 groups based on a match/mismatch with the chronotype: Type M-match (n = 8), Type M-mismatch (n = 6), Type E-match (n = 7), and Type E-mismatch (n = 8) groups. The data were compared among the 4 groups. Moreover, multiple regression analysis was conducted using an increase (kg) LBM gain as a response variable. When comparing the data between the “Morningness” and “Eveningness” participants, there were no differences in nutrient intake, the duration of training, or each parameter of body composition (per body weight) at baseline or after 4 months. There were also no differences in the rates of change in the body weight or each parameter of body composition. In groups in which the chronotype was consistent with the SWC-W (the Type M-match and Type E-match groups), the LBM gain were slightly greater than in the Type M-mismatch and Type E-mismatch groups (Type M-match: 3.5 ± 2.0 kg, Type M-mismatch: 1.6 ± 1.7 kg, Type E-match: 3.4 ± 2.2 kg, and Type E-mismatch: 1.2 ± 1.8 kg, p = .057). Multiple regression analysis revealed that an extent of the LBM gain was associated with a match between the chronotype and SWC-W (ß = 0.37, p = .030), independent of a long duration of training (ß = 0.52, p = .004). The results suggested that training-related LBM gain is associated with interactions between the chronotype and SWC-W in adolescent male athletes. Abbreviations: LBM: Lean body mass; SWC-W: Sleep-wake cycle on weekdays; ME score: Morningness-eveningness score; MES-C: Morningness/Eveningness Scale for Children; MSW: Midpoint of sleep on weekdays; MSF: Midpoint of sleep on free days; MSFsc: Midpoint of sleep on free days corrected for sleep debt accumulated through weekdays

The onset of pubertal development and actigraphy-assessed sleep during middle childhood: Racial, gender, and genetic effects

ObjectiveThis study (1) examined pubertal development in relation to actigraphy-assessed sleep in twin children, and tested whether associations differed by child race and gender, (2) modeled genetic and environmental influences on pubertal development and sleep indicators, and (3) examined genetic and environmental influences on the covariation of puberty and sleep. DesignThe classic twin design was used to examine genetic and environmental contributions to puberty and sleep and their associations. SettingData were collected from community-dwelling urban and rural families of twins in the southwestern U.S. ParticipantsThe racially and socioeconomically diverse sample included 596 twin children (Mage = 8.41, SD = 0.69; 51.7% female; 66.3% white; 33.7% Hispanic; 170 monozygotic, 236 same-sex dizygotic, 188 opposite-sex dizygotic). MeasurementsPubertal development was assessed via parent report. Children wore actigraph watches for 7 nights (M = 6.81, SD = 0.67) to capture sleep duration, efficiency, midpoint, onset latency, and duration variability. ResultsIn contrast to extant literature with older youth, more advanced pubertal development was associated with longer sleep durations in Hispanic and white girls and higher sleep efficiency in white girls, though Hispanic girls demonstrated later sleep midpoints. Pubertal development was moderately heritable and there was a genetic influence on the covariance between puberty and sleep indicators. ConclusionsThis was the first study to examine the genetic and environmental influences on the covariation between puberty and sleep, and found genetic underpinnings between pubertal development and actigraphy-assessed sleep duration and efficiency, though sleep and puberty were almost entirely independent in twins at this age.

Relationships between the Munich Chronotype questionnaire index and time at minimum core temperature

ABSTRACT The purpose of this study was to examine the correlation between the Munich ChronoType Questionnaire (MCTQ) index and time at minimum core temperature. Nine athletes were requested to answer the MCTQ questionnaire and monitor their core temperature during night. In the MCTQ, the midpoint of sleep on free day, which is corrected for sleep debt accumulated during the workweek (MSFsc), was calculated. The core temperature was monitored using a telemetric system with an ingestible capsule-type sensor. The correlation between the MSFsc and the time at the lowest core temperature was examined. The range of MSFsc and time at minimum core temperature were 2.54–7.75 (mean ±SE: 4.54 ± 0.52, 95%CI: 3.52–5.55) and 3:43–7:41 (mean ±SE: 5:24 ± 0:32, 95%CI: 4:21–6:27), respectively. Four participants with their MSFsc later than 4.96 showed times at minimum core temperature later than 6:00. A significant correlation between the MSFsc and time at minimum core temperature was observed, with a very high correlation coefficient (r = 0.86, p < 0.01). These results suggest that the MSFsc may be useful to find athletes who have a better chance to advance their circadian rhythmicity for morning competitions.

Early life socioeconomic differences in associations between childhood sleep and academic performance

Poor sleep can negatively impact children's academic performance. However, it is unknown whether early-life socioeconomic status (SES) moderates later sleep and academics. We tested associations between actigraphy-based sleep duration and midpoint time, and parent-reported sleep problems with objective and subjective measures of academic performance. We also examined whether relations varied by early and concurrent SES. Children (n = 707; 52% female; Mage = 8.44 years; 28.7% Hispanic/Latino; 29.7% at/below poverty line) were assessed at 12 months for SES and eight years for SES, sleep, and academics. There were no main effects of sleep on academics. More sleep problems predicted lower Applied Problems performance for low SES children (b = −0.73, p < .05) and better performance for high SES children (b = 0.69, p < .05). For high SES children, greater sleep problems (b = −0.11, p < .05) and longer sleep duration (b = −0.11, p < .05) predicted lower academic achievement. However, most associations were consistent across SES, illustrating the complex interplay between sleep, academic outcomes, and SES.

Validation of the Chinese version of the Munich Chronotype Questionnaire (MCTQHK) in Hong Kong Chinese youths

ABSTRACT Chronotype, referred to as an individual’s diurnal preference of timing for rest and activity, can be subjectively measured using the Munich Chronotype Questionnaire (MCTQ). However, the validity of MCTQ has yet to be tested in the youth population. In addition, it remains uncertain if MCTQ is a good measure of chronotype in individuals with insomnia. The current study aimed to validate the Chinese version of MCTQ (MCTQHK) in the youth population and to explore the utility of MCTQHK in individuals with insomnia. The original MCTQ was translated into Chinese language using the translation-back-translation method. Part one of this study included 988 youths who completed a battery of self-report questionnaires online consisting of the MCTQHK and the morningness-eveningness questionnaire (MEQ) for the measures of circadian preference, Insomnia Severity Index (ISI) to assess insomnia symptoms, and Patient Health Questionnaire (PHQ-9) to measure depressive symptoms. Test–retest reliability was examined in 442 participants at one-month follow-up. Of the overall sample, 69 participants were randomly drawn to complete the second part of the study, which included prospective 7-day actigraphy monitoring and a further subset (n = 40) additionally completed a laboratory-based assessment of dim-light melatonin onset (DLMO) as a circadian phase marker. A total of 659 participants with valid responses were finally included in the analyses of the data collected from part one of the study (female = 67.7%; mean age: 20.7 ± 2.02). Results showed that MCTQ parameters, namely the midpoint of sleep on free days (MSF), midpoint of sleep on workdays (MSW), and midpoint of sleep adjusted for sleep debt (MSFsc), were significantly correlated with MEQ score (r = −.514 to −.650, p < .01). Test–retest reliability for MCTQHK was good (intraclass correlation = 0.75 to 0.84). Later MSFsc was significantly associated with greater insomnia and depressive symptoms after controlling for age and sex. All MCTQ parameters showed significant correlations with actigraphy-based midpoint of sleep and circadian rhythm parameters, i.e., acrophase and L5 onset (r = .362 to .619, p < .01), as well as DLMO (r = .393 to .517, p < .05). The associations remained significant after controlling for age. MSFsc derived from MCTQ was significantly correlated with MEQ score in both the healthy sleepers and participants with insomnia (as defined by ISI > 14), r = −.600, p < .001 and r = −.543, p < .001, respectively. The present study demonstrated that MCTQHK is suitable for assessing chronotype with good reliability and validity in Chinese youths and supported the utility of MCTQHK in individuals with insomnia.

Too Jittery to Sleep? Temporal Associations of Actigraphic Sleep and Caffeine in Adolescents.

Caffeine consumption has been linked to poor sleep health in adolescents, but it is unknown whether poor sleep predicts caffeine consumption, and/or whether caffeine consumption predicts poor sleep, particularly when sleep is measured objectively. Data were collected from a micro-longitudinal sub-study of the age 15 wave of the Fragile Families and Child Wellbeing Study (n = 589). Adolescents wore an actigraphy device and completed daily surveys for ~1 week. Daily surveys assessed subjective sleep quality and caffeinated beverage consumption (0 = no caffeine, 1 = any caffeine). Separate mixed models assessed whether actigraphy-measured sleep duration, timing, maintenance efficiency, and subjective quality predicted next-day caffeinated beverage consumption within and between adolescents. Variability (standard deviation) of sleep duration and timing, sleep regularity index, and social jetlag were tested as additional between-person predictors. Lagged models tested whether daily caffeinated beverage consumption predicted sleep that night (n = 458). Adolescents with more variable sleep duration and midpoint had higher average odds of consuming caffeinated beverages compared to others. After adolescents consumed ≥1 caffeinated beverage, they had later sleep onset that night and wake time the next morning than usual versus when they did not consume caffeine. Curbing caffeinated beverage consumption may aid in the maintenance of regular sleep schedules and advance sleep timing in adolescents.

Links Between Personality and Sleep Midpoint in Older Adults in the National Social Life, Health, and Aging Project

Chronotype has been linked to poor cognitive outcomes and mortality among older adults. Although previous studies indicate an association between personality and sleep, little is known about associations between personality and chronotype in older adults. We examined the association between personality and objective sleep midpoint (a measure of chronotype) in 463 older adults aged 73.5 ±7.7 from the National Social Life, Health, and Aging Project who completed the Midlife Developmental Inventory Personality scale and three nights of wrist actigraphy, from which we derived participants’ average sleep midpoints. After adjusting for demographics, higher conscientiousness was associated with earlier sleep midpoint (B=-0.53, SE=0.02, p<0.01). Associations for other traits were not significant. Findings link conscientiousness to chronotype and raise the possibility that earlier sleep timing may partially account for associations of conscientiousness with health outcomes. Further studies are needed investigating the role of personality in links of sleep and circadian factors with health.

Impact of insufficient sleep on dysregulated blood glucose control under standardised meal conditions

Aims/hypothesisSleep, diet and exercise are fundamental to metabolic homeostasis. In this secondary analysis of a repeated measures, nutritional intervention study, we tested whether an individual’s sleep quality, duration and timing impact glycaemic response to a breakfast meal the following morning.MethodsHealthy adults’ data (N = 953 [41% twins]) were analysed from the PREDICT dietary intervention trial. Participants consumed isoenergetic standardised meals over 2 weeks in the clinic and at home. Actigraphy was used to assess sleep variables (duration, efficiency, timing) and continuous glucose monitors were used to measure glycaemic variation (>8000 meals).ResultsSleep variables were significantly associated with postprandial glycaemic control (2 h incremental AUC), at both between- and within-person levels. Sleep period time interacted with meal type, with a smaller effect of poor sleep on postprandial blood glucose levels when high-carbohydrate (low fat/protein) (pinteraction = 0.02) and high-fat (pinteraction = 0.03) breakfasts were consumed compared with a reference 75 g OGTT. Within-person sleep period time had a similar interaction (high carbohydrate: pinteraction = 0.001, high fat: pinteraction = 0.02). Within- and between-person sleep efficiency were significantly associated with lower postprandial blood glucose levels irrespective of meal type (both p < 0.03). Later sleep midpoint (time deviation from midnight) was found to be significantly associated with higher postprandial glucose, in both between-person and within-person comparisons (p = 0.035 and p = 0.051, respectively).Conclusions/interpretationPoor sleep efficiency and later bedtime routines are associated with more pronounced postprandial glycaemic responses to breakfast the following morning. A person’s deviation from their usual sleep pattern was also associated with poorer postprandial glycaemic control. These findings underscore sleep as a modifiable, non-pharmacological therapeutic target for the optimal regulation of human metabolic health.Trial registrationClinicalTrials.gov NCT03479866.Graphical abstract

Abstract 9150: Actigraphy-Derived Sleep Health Metrics and Biomarkers of Cardiovascular Disease Risk in Black/African American Smokers

Introduction: Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in Black/African American (BAA) adults, and to a greater extent in BAAs who smoke cigarettes. Sleep is an emergent predictor of CVD, yet the independent role of sleep health on CVD risk in BAA smokers is unclear. Thus, we tested the hypothesis that better sleep health metrics would be independently associated with more favorable biomarkers of CVD risk in midlife BAA smokers. Methods: BAA adults (n=226, 55.9±6.1y, 44% male) who were current smokers (≥1 cigarette in last month) without sleep-disordered breathing or severe lung disease completed 14 days of wrist actigraphy to assess sleep duration, efficiency, midpoint, and regularity (sleep midpoint standard deviation). Resting blood pressure (BP) and heart rate recovery (HRR; HR peak minus HR 1-min recovery from submaximal exercise) were assessed. Hypertension was defined as resting BP ≥130/80 mmHg, or use of antihypertensives. Multivariable regression models of systolic BP, diastolic BP, hypertension (yes/no), and HRR were generated to test associations between sleep metrics and CVD risk markers after adjusting for key covariates (see Table). Results: In adjusted models, achieving a healthy sleep duration (6-8 h/night) was associated with 62% lower odds of hypertension (vs. &lt;6 or &gt;8h/night; OR=0.38, 95% CI=0.18-0.75). Later sleep midpoint was associated with higher systolic BP (B=1.97 mmHg per 1-h delay in midpoint, 95% CI=0.17-3.81); longer sleep duration (B=1.89 bpm per 1-h increase in duration, 95% CI=0.39-3.39) and greater sleep efficiency (B=0.27 bpm per 1% increase in efficiency, 95% CI=0.08-0.46) were associated with greater HRR. Conclusions: Better sleep health metrics are associated with a lower CVD risk profile in BAA smokers, independent of important confounding factors. Sleep health may represent an auxiliary intervention target for ameliorating the CVD burden experienced by this at-risk group.

Social jetlag among Japanese adolescents: Association with irritable mood, daytime sleepiness, fatigue, and poor academic performance

ABSTRACT Social jetlag, a form of circadian misalignment, has been suggested to induce several clinical symptoms such as mental/physical health problems. However, evidence on the association of social jetlag with general daytime functioning (e.g., school life) is limited. This cross-sectional study aimed to 1) estimate the distribution of social jetlag exceeding one hour and 2) comprehensively explore the associations between social jetlag and irritable mood, daytime sleepiness, and poor academic performance among Japanese adolescents. The study included 4,782 students aged 12–15 years, from 13 junior high schools, who completed a self-administered questionnaire. Social jetlag was calculated as the difference in the midpoint of sleep between weekdays and weekends and was categorized as follow: negative, <1 h, 1–2 h, or ≥2 h. Outcomes were irritable mood, daytime sleepiness, and academic performance, which were analyzed with generalized linear mixed models to examine the relations with social jetlag, with adjustments for potential confounders like sleep quality. The distribution of social jetlag of ≥1 h was 51.1%, including 1–2 h (35.8%) and ≥2 h (15.3%). Its most frequently observed duration was 0 to <1 h (41.0%), followed by negative social jetlag (7.9%). The full adjusted model revealed that social jetlag of ≥1 h was associated with elevated risk of irritable mood, daytime sleepiness, and poor academic performance, while negative social jetlag was associated only with poor academic performance. Social jetlag was highly prevalent among Japanese adolescents and could be a major risk factor for irritable mood, daytime sleepiness, and poor academic performance. Abbreviations: BMI, Body mass index; DLMO, Dim light melatonin onset; CIs, Confidence intervals; MSF, The midpoints of sleep on free days; MSFsc, Sleep-corrected MSF; MSW, The midpoints of sleep on weekdays; PDSS, The Pediatric Daytime Sleepiness Scale.

Longitudinal associations between facets of sleep and adiposity in youth.

Beyond sleep duration, other facets of sleep such as variability and timing may be associated with obesity risk in youth. However, data are limited. Using a longitudinal design, this study tested whether multiple facets of sleep were associated with fat mass gain over 1 year. A convenience sample of non-treatment-seeking youth (age 8-17 years) wore actigraphy monitors for 14 days. Average weekly sleep duration, within-person sleep duration variability, weekend catch-up sleep, bedtime and wake time shift, social jet lag, bedtime, wake time, and sleep midpoint were calculated. The association of each facet of baseline sleep with 1-year fat mass, adjusting for baseline fat mass and height, was examined. A total of 137 youths (54.0% female; mean [SD], age 12.5 [2.6] years; 28.4% non-Hispanic Black or African American; baseline fat mass = 15.3 [8.9] kg; 1-year fat mass = 17.0 [10.0] kg; 28.5% with baseline overweight or obesity) were studied. Wake time (p = 0.03) and sleep midpoint (p = 0.02) were inversely associated with 1-year fat mass, such that earlier wake time and midpoint were associated with higher 1-year fat mass. No other facet of sleep was significantly associated with 1-year fat mass (p > 0.09). Using objective measures, youth with earlier wake times and sleep midpoints had greater gains in fat mass. Additional research is needed to determine whether sleep timing may be a modifiable target to prevent pediatric obesity.

Changes in chronotype and social jetlag during adolescence and their association with concurrent changes in BMI-SDS and body composition, in the DONALD Study

Background/objectivesAdolescence is a critical period for both the development of overweight and the transition toward a later chronotype, often accompanied by an increase in social jetlag. This study assessed whether changes in chronotype and social jetlag, are linked to changes in body composition during adolescence.Subjects/methodsWe used data from the DONALD open cohort study, collected between 2014 and 2019, from 213 adolescents (9–17 years at baseline, 45% females) having at least two measures of chronotype and anthropometry (N = 572). Chronotype was assessed with the Munich Chronotype Questionnaire and defined as: midpoint of sleep corrected for sleep-debt (MSFsc) accumulated over the week (later MSFsc represents later chronotype). Social jetlag (SJL) defines the difference between midpoint of sleep during week and weekend. Calculations for Fat Free Mass Index (FFMI [kg/m2)]) and Fat Mass Index (FMI) [kg/m2)]) were based on body fat percentage, weight, and height. To analyze the associations, we used linear mixed-effect regression models. Finally, the total cohort was split into three biologically relevant age groups (cut-off set at <12 years, ≥12 to ≤15 years and >15 years).ResultsMedian follow-up was 2.1 years. Overall, change toward a later chronotype was significantly related with an increase in FMI (ß: 0.05, 95% CI: 0.01–0.08). A 1 h increase in social jetlag predicted an increase in BMI-SDS of 0.08 SDS units (95% CI: 0.01–0.14) and in FMI of 0.04 kg/m2 (95% CI: 0.003–0.08). Associations were stronger for the age group ≥12 to ≤15 years (p for interaction: <0.001). No relationship was found with FFMI.ConclusionsChanges in MSFsc and SJL during adolescence were associated with concurrent changes in BMI-SDS and FMI. The age ≥12 to ≤15 years appears to be a sensitive period in which chronobiological changes were clearly associated with increasing body fatness.

An observational study investigating the CRY1\u039411 variant associated with delayed sleep\u2013wake patterns and circadian metabolic output

We conducted an observational research study to collect information on sleep–wake patterns from participants with a confirmed status of the cryptochrome circadian clock 1 (CRY1) splicing variant, CRY1Δ11 c.1657 + 3A > C, and their controls, defined as wild-type (WT) family members. Altogether, 67 participants were enrolled and completed this study in Turkey, recruited from a list of families with at least one CRY1-confirmed member. We measured sleep–wake patterns and metabolic output, specifically time and frequency of bowel movements, for all participants by daily post-sleep diaries over 28 days. The sleep diary measured self-reported bed time, wake time, midpoint of sleep, and latency to persistent sleep (LPS), and accounted for naps and awakenings for religious purposes. Wake time and midpoint of sleep were significantly later in the CRY1Δ11 variant group versus WT, and LPS was significantly greater in participants in the CRY1Δ11 variant group. The mean bed time on all nights of sleep was later in participants with a CRY1Δ11 variant versus WT. Additionally, participants with a CRY1Δ11 variant had significantly affected metabolic outputs, measured by later bowel movements than WT participants. These results demonstrate that, on average, individuals with the studied splicing variant experience pronounced delays in sleep period and circadian-related metabolic processes.

Social Jetlag and Cardiometabolic Risk in Preadolescent Children.

Objective: Childhood cardiometabolic disease risk (CMD) has been associated with short sleep duration. Its relationship with other aspects of sleep should also be considered, including social jetlag (SJL) which represents the difference between a person's social rhythms and circadian clock. This study investigated whether childhood CMD risk is associated with sleep duration, sleep disturbances, and SJL.Study Design: The observational study included 332 children aged 8–10 years (48.5% female). The three independent variables were sleep duration, sleep disturbances, and SJL. SJL was calculated as the variation in hours between the midpoint of sleep during free (weekend) days and work/school days. Eleven cardiometabolic biomarkers were measured, including central blood pressure, lipids, glycated hemoglobin, arterial wave reflection, and glucose. Underlying CMD risk factors were identified using factor analysis.Results: Four underlying CMD risk factors were identified using factor analysis: blood pressure, cholesterol, vascular health, and carbohydrate metabolism. Neither sleep disturbances nor sleep duration were significantly associated with any of the four CMD factors following adjustments to potential confounders. However, SJL was significantly linked to vascular health (p = 0.027) and cholesterol (p = 0.025).Conclusion: These findings suggest that SJL may be a significant and measurable public health target for offsetting negative CMD trajectories in children. Further studies are required to determine biological plausibility.

Sleep Problems and Circadian Functioning in Children and Adolescents With Autism Spectrum Disorder

BackgroundSleep problems are a prevalent comorbidity in autism spectrum disorder (ASD) with a multifactorial basis in which circadian misalignment has been described. MethodsA cross-sectional study was conducted including 52 children and adolescents with ASD (9.85 ± 3.07) and 27 children and adolescent controls with normal intellectual functioning (8.81 ± 2.14). They were matched for age, sex, and body mass index, and all were drug-naïve. An ambulatory circadian monitoring device was used to record temperature and motor, body position, sleep, and light intensity. ResultsIndividuals with ASD presented longer sleep-onset latency, lower sleep efficiency, and decreased total sleep time and tended to be more sedentary and have less exposure to light. They also showed lower amplitude, low interdaily stability, and a different pattern of wrist temperature across the day, with a midpoint of sleep that did not concur with sleep midpoint indicated by the rest of circadian parameters. ConclusionsThe sleep problems observed in this sample resemble those reported previously, with the exception of nocturnal awakenings which did not show differences. The ambulatory circadian monitoring device enabled measurement of circadian parameters such as temperature which, until now, were scarcely described in children with ASD and could be used to better understand sleep and circadian system in ASD.