Midpoint Of Sleep Research Articles

231 COVID-19 Lockdown Policies Across 20 Countries Modulate Sleep and Resting Heart Rate Measures

IntroductionLockdowns imposed to stem the spread of COVID-19 have disrupted the lifestyles of many worldwide, but studies to date are mostly confined to observations within a limited number of countries, based on subjective reports and survey from a narrow time window. In the present study, we investigate associations between the severity of lockdown policies and objective sleep and resting-heart rate measures.MethodsData from 113,000 users of a consumer sleep tracker across 20 countries were gathered between Jan–Jul 2020 and compared with an equivalent period in 2019 as a control for naturally occurring seasonal fluctuations. Lockdown stringency was derived using scores from the Oxford Government Response Tracker. Multilevel growth curve models were used to quantify the effect of lockdown stringency on changes to sleep patterns (midsleep time and midsleep variability) and resting heart rate changes, and to predict changes in resting heart rate from changes to sleep patterns.ResultsLockdown severity modulated the size of shifts in sleep midpoint and regularity during this period. Midsleep times were delayed in all countries during strict lockdowns, particularly on weekdays, while midsleep variability reduced. The largest shifts in midsleep time (+0.09 to +0.58 hours), midsleep variability (–0.12 to –0.26 hours) and resting heart rate (–0.35 to –2.08 bpm) occurred in April and May - when most countries imposed their strictest lockdown measures. In addition, multilevel modelling revealed that for each unit increase in stringency index, midsleep time was delayed by 0.96 min, midsleep variability decreased by 0.46 min and resting heart rate decreased by 0.06 bpm. Finally, in models predicting changes in resting heart rate from changes to sleep patterns, midsleep variability was shown to be the strongest predictor of resting heart rate, wherein an hour increase in the standard deviation of midsleep variability predicted a 5.12 increase in bpm, while an hour increase in midsleep time only predicted a 1.25 decrease in bpm.ConclusionOur findings demonstrate the utility of large-scale data from consumer wearables in providing population-level insights into how lockdown severity directly impacts sleep health during this pandemic period.Support (if any)Work conducted at NUS is supported by a grant awarded to Michael Chee (NMRC/STAR19may-0001).

582 Insomnia-related cognitive and behavioural factors in adolescents with delayed sleep-wake phase disorder

Abstract Introduction Although delayed sleep-wake phase disorder (DSWPD) shares phenomenological experiences with chronic insomnia disorder, previous research on the conceptual understanding of DSWPD has been limited, with a predominant focus on its chronobiological basis. The present study examined several insomnia-related cognitive and behavioural factors in adolescents with DSWPD. Methods Twenty-five adolescents with DSWPD (age = 19.9 ± 1.6; female = 28%), 28 with chronic insomnia disorder (age = 20.4 ± 2.0; female = 61%), diagnosed according to the ICSD-3 criteria, and 25 healthy control (age = 20.4 ± 1.5; female = 68%) were included in the present study. Participants completed 7-day prospective sleep diary and actigraphy monitoring, and a battery of questionnaires on sleep and chronotype measures. Participants were also measured on hyperarousal (Pre-Sleep Arousal Scale, PSAS), sleep reactivity (Ford Insomnia Response to Stress Test, FIRST), sleep-related beliefs (Dysfunctional Beliefs and Attitudes about Sleep, DBAS-16), and sleep hygiene practices (Sleep Hygiene Practices Scale, SHPS). Analysis of covariance (ANCOVA) with gender as the covariate was used for between-group comparisons. Results Relative to healthy control group, insomnia and DSWPD group showed significantly more insomnia symptoms as measured by Insomnia Severity Index (p<.001). As compared to healthy control group, DSWPD group showed significantly more delay in circadian phase based on sleep diary and actigraphy derived mid-point of sleep, as well as greater preference towards eveningness as measured by the Morningness-Eveningness Questionnaire. DSWPD group also showed significantly more cognitive and somatic hyperarousal (p<.001, d = 1.36–2.31), sleep reactivity (p<.001, d = 1.73), dysfunctional belief about sleep (p<.001, d = 1.59), as well as poorer sleep hygiene practices (p<.001, d = 2.62), compared to healthy control. There were no significant differences in the circadian parameters, PSAS, FIRST, DBAS-16, and SHPS between DSWPD and insomnia groups. Conclusion Several insomnia-related cognitive and behavioural factors, namely hyperarousal, sleep reactivity, maladaptive beliefs about sleep, and poor sleep hygiene, are also evident in youths with DSWPD. The findings had important implications for the conceptual understanding and clinical management of DSWPD. Support (if any) This work was supported by the Seed Fund for Basic Research (University Research Committee, The University of Hong Kong) awarded to Dr. Shirley Li.

238 Adolescent Sleep Variability, Social Jetlag, and Mental Health during COVID-19: Findings from a Large Nationwide Study

IntroductionAdolescents are vulnerable to short, insufficient sleep stemming from a combined preference for late bedtimes and early school start times, and also circadian disruptions from frequent shifts in sleep schedules (i.e., social jetlag). These sleep disruptions are associated with poor mental health. The COVID-19 pandemic has impacted education nationwide, including changes in instructional formats and school schedules. With data from the Nationwide Education and Sleep in TEens During COVID (NESTED) study, we examined whether sleep variability and social jetlag (SJL) during the pandemic associate with mental health.MethodsAnalyses included online survey data from 4767 students (grades 6-12, 46% female, 36% non-White, 87% high school). For each weekday, participants identified if they attended school in person (IP), online-scheduled synchronous classes (O/S), online-no scheduled classes (asynchronous, O/A), or no school. Students reported bedtimes (BT) and wake times (WT) for each instructional format and for weekends/no school days. Sleep opportunity (SlpOpp) was calculated from BT and WT. Weekday night-to-night SlpOpp variability was calculated with mean square successive differences. SJL was calculated as the difference between the average sleep midpoint on free days (O/A, no school, weekends) versus scheduled days (IP, O/S). Participants also completed the PROMIS Pediatric Anxiety and Depressive Symptoms Short Form. Data were analyzed with hierarchical linear regressions controlling for average SlpOpp, gender, and school-level (middle vs high school).ResultsMean reported symptoms of anxiety (60.0 ±9.1; 14%≧70) and depression (63.4 ±10.2; 22%≧70) fell in the at-risk range. Shorter average SlpOpp (mean=8.3±1.2hrs) was correlated with higher anxiety (r=-.10) and depression (r=-.11; p’s<.001) T-scores. Greater SlpOpp variability was associated with higher anxiety (B=.71 [95%CI=.41-1.01, p<.001) and depression (B=.67 [.33-1.00], p<.001) T-scores. Greater SJL (mean=1.8±1.2hrs; 94% showed a delay in midpoint) was associated with higher anxiety (B=.36 [.12-.60], p<.001) and depression (B=.77 [.50-1.03], p<.001) T-scores.ConclusionIn the context of system-wide education changes during COVID-19, students on average reported at-risk levels of anxiety and depression symptoms which were associated with greater variability in sleep opportunity across school days and greater social jetlag. Our findings suggest educators and policymakers should consider these sleep-mental health associations when developing instructional formats and school schedules during and post-pandemic.Support (if any)T32MH019927(P.W.)

105 Sleep Behaviors Are Differentially Associated with Eating Behavior Characteristics Based on Sex

Abstract Introduction Poor sleep health is a key determinant of obesity risk, largely explained by overconsumption of energy. Eating behavior characteristics are predictive of energy intake and weight change and may link sleep with risk factors for obesity. However, the relationships between sleep and dimensions of eating behavior, and potential individual differences in these relations, are not well characterized. Elucidating these relations may aid in the development of targeted strategies to mitigate obesity risk. Therefore, we aimed to 1) evaluate whether associations of sleep were related with eating behavior characteristics, 2) explore if these associations differed by sex. Methods This was a cross-sectional analysis of 179 adults aged 20–73 y (68.7% women; 64.8% with BMI≥25 kg/m2; 27.4% minority). Sleep was assessed over 2 wk using wrist actigraphy; eating behavior characteristics (dietary restraint, disinhibition and hunger) were measured with the Three-Factor Eating Questionnaire. Linear regression models were used to evaluate associations of sleep with eating behavior characteristics, adjusting for confounding variables. In separate models, sex was added as an interaction term and analyses were stratified when interactions were significant (p&amp;lt;0.10). Results Variable (sleep midpoint standard deviation &amp;gt;60 min) vs. stable sleep timing was associated with greater tendency towards hunger (β=0.84 ± 0.39, p=0.03). When evaluated on the continuous scale, lower sleep efficiency (β=-0.13 ± 0.05; p=0.01), longer wake after sleep onset (β=0.03 ± 0.01; p=0.01) and higher sleep fragmentation index (β=0.074 ± 0.036; p=0.041) were associated with higher dietary restraint. Sex influenced associations of sleep efficiency, sleep onset latency, and sleep fragmentation index with hunger. In men, but not women, lower sleep efficiency (β=-0.15 ± 0.05; p&amp;lt;0.01), longer sleep onset latency (β=0.17 ± 0.07; p=0.02) and higher sleep fragmentation index (β=0.11 ± 0.04; p&amp;lt;0.01) were associated with greater hunger. Conclusion Objective measures of sleep were associated with eating behaviors previously linked with obesity and its risk factors. Moreover, we provide evidence of sex-specific associations between poor sleep and tendency towards hunger. Our results suggest that, particularly in men, differences in eating behavior traits may underlie susceptibility to overeating in response to poor sleep. Support (if any) Supported by NIH grants R01HL128226 and R01HL142648 and AHA grant 16SFRN27950012 (PI: St-Onge).

235 Age and Chronotype Associated with Sleep Timing Changes During COVID-19-Related Lockdowns in the US

IntroductionGlobal lockdowns implemented to reduce spread of the Coronavirus Disease 2019 (COVID-19) have offered unique insight into how sleep patterns change when typical social obligations are significantly reduced. Here, we aimed to replicate findings of sleep timing delays and reduced social jetlag during lockdown using a large, regionally-diverse sample of participants from the United States (US). Further, we conducted exploratory analyses to determine if observed sleep changes were associated with age and self-reported chronotype.MethodsA sample of 691 US adults (age 18-89) completed the Ultrashort Munich Chronotype Questionnaire twice during the same assessment: once querying retrospective memory for sleep patterns in the 6-weeks prior to February 1, 2020 (Pre-Lockdown) and a second time for sleep patterns in the 6-weeks prior to ~May 20th (Peak-Lockdown in the US). Participants also completed the abbreviated Morningness-Eveningness Questionnaire to assess chronotype. We compared sleep duration (SDur), sleep onset time (SO), sleep end time (SEnd), social jetlag (SJL; difference between work-day and free-day sleep midpoint) and social sleep restriction (SSR; difference between work-day and free-day sleep duration) Pre- to Peak-Lockdown. We conducted exploratory analyses to determine whether Pre- to Peak-Lockdown changes in these sleep metrics were associated with age or chronotype. Main analyses were preregistered with Open Science Framework (https://osf.io/4a3fx).ResultsDuring the Peak-Lockdown period, participants, on average, reported significantly later SO and SEnd times and significantly reduced SJL and SSR compared with the Pre-Lockdown period. Change in SJL and SSR Pre- to Peak-Lockdown was significantly positively associated with age and chronotype such that SJL and SSR decreased more during lockdown in younger participants and those with an evening chronotype.ConclusionOur results support lockdown-associated sleep timing delays and reduced SJL and SSR. Younger age and evening chronotype were associated with greater reductions in SJL and SSR during lockdown. These findings suggest that individuals, particularly young individuals and those with an evening chronotype, experience greatest desynchrony between intrinsic and social sleep timing when conforming to typical pre-pandemic social schedules.Support (if any)Harvard Medical School Division of Sleep Medicine T32 HL007901 (RB and TJC); Brandeis University NIH NRSA T32 NS007292 (ECF)

Meal and Sleep Timing before and during the COVID-19 Pandemic: A Cross-Sectional Anonymous Survey Study from Sweden.

The COVID-19 pandemic and related restrictions, such as stay-at-home-orders, have significantly altered daily routines and lifestyles. Given their importance for metabolic health, we herein compared sleep and meal timing parameters during vs. before the COVID-19 pandemic based on subjective recall, in an anonymous Swedish survey. Among 191 adults (mean age: 47 years; 77.5% females), we show that social jetlag, i.e., the mismatch in sleep midpoint between work and free days, was reduced by about 17 min during the pandemic compared with the pre-pandemic state (p < 0.001). Concomitantly, respondents’ sleep midpoint was shifted toward morning hours during workdays (p < 0.001). A later daily eating midpoint accompanied the shift in sleep timing (p = 0.001). This effect was mainly driven by a later scheduled first meal (p < 0.001). No difference in the timing of the day’s last meal was found (p = 0.814). Although our survey was limited in terms of sample size and by being cross-sectional, our results suggest that the delay in sleep timing due to the COVID-19 pandemic was accompanied by a corresponding shift in the timing of early but not late meals.

Genetically proxied morning chronotype was associated with a reduced risk of prostate cancer.

Observational epidemiological studies have suggested that chronotype may play a role in the pathogenesis and progression of prostate cancer. However, whether there is a causal association remains unknown. The aim of the present study was to examine the potential causal relationship between chronotype and prostate cancer risk using a Mendelian randomization (MR) design. A total of 268 single nucleotide polymorphisms associated with chronotype were selected from a meta-analysis of genome-wide association studies of 697,828 individuals. The genetic association data for prostate cancer was derived from the Prostate Cancer Association Group to Investigate Cancer-Associated Alterations in the Genome (PRACTICAL) Consortium (79,148 cases and 61,106 controls). Inverse-variance weighted (IVW) method was used as the primary analysis to calculate the causal effect estimates. The weighted-median method, MR-Egger regression, MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO) test, and multivariable MR analyses were applied as sensitivity analysis. Genetically predicted morningness (scaled to a sleep midpoint of 1 h earlier) had a reduced risk of prostate cancer, with an odds ratio of 0.71 (95% confidence interval [CI]: 0.54-0.94 by IVW), compared with the eveningness. Similar causal effect estimates were also observed by using the weighted median and MR-PRESSO analyses. In addition, results from the multivariable MR analysis supported the findings from the univariable MR analyses. No indication of horizontal pleiotropy was observed in the MR-Egger analysis (p for intercept = 0.234). Our findings provide evidence of a causal protective effect of morning chronotype on the risk of prostate cancer.

Conscientiousness and Cardiometabolic Risk: A Test of the Health Behavior Model of Personality Using Structural Equation Modeling.

High trait conscientiousness is associated with lower cardiometabolic risk, and health behaviors are a putative but relatively untested pathway that may explain this association. To explore the role of key health behaviors (diet, physical activity, substance use, and sleep) as links between conscientiousness and cardiometabolic risk. In a cross-sectional analysis of 494 healthy, middle-aged working adults (mean age = 42.7 years, 52.6% women, 81.0% White), participants provided self-reports of conscientiousness, physical activity, substance use, diet, and sleep, and wore monitors over a 7-day monitoring period to assess sleep (Actiwatch-16) and physical activity (SenseWear Pro3). Cardiometabolic risk was expressed as a second-order latent variable from a confirmatory factor analysis involving insulin resistance, dyslipidemia, obesity, and blood pressure. Direct, indirect, and specific indirect effect pathways linking conscientiousness to health behaviors and cardiometabolic risk were examined. Unstandardized indirect effects for each health behavior class were computed separately using bootstrapped samples. After controlling for demographics (sex, age, race, and education), conscientiousness showed the predicted, inverse association with cardiometabolic risk. Among the examined health behaviors, objectively-assessed sleep midpoint variability (b = -0.003, p = .04), subjective sleep quality (b = -0.003, p = .025), and objectively-assessed physical activity (b = -0.11, p = .04) linked conscientiousness to cardiometabolic risk. Physical activity and sleep partially accounted for the relationship between conscientiousness and cardiometabolic risk.

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

ObjectivePoor 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 & settingTransgender males age 13-16 were recruited from a U.S. gender diversity clinic. MeasurementsParticipants completed one week of home actigraphy monitoring. Questionnaires assessed insomnia symptoms, chronotype, mood, and HRQOL. Pearson correlations between sleep, mood, and HRQOL were examined. ResultsA 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. ConclusionsAnxiety 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.

Modified Munich chronotype questionnaire for application to short-interval split sleep of non-shift workers

ABSTRACT The Munich Chronotype Questionnaire (MCTQ) has been widely validated among various types of populations. However, determination of chronotype among individuals who have a split sleep pattern with short intervals between the first and second sleep bouts on free days has not yet been reported. This study aimed to validate the MCTQ modified for this purpose by assessing the actual sleep-wake timing against the Morningness-Eveningness Questionnaire (MEQ). The modified calculation for the midpoint of sleep on free days (MSF) of the split sleep pattern considers the second sleep bout as the total sleep duration on free days. We recruited 161 participants (mean age: 38.7 ± 7.8 years; 73% females, 29% with split sleep pattern) were recruited to administer the modified version of the MCTQ and MEQ. All of the MCTQ original parameters: midpoint of sleep on work days (MSW, r = −0.575), midpoint of sleep on free days (MSF, r = −0.568), and midpoint of sleep on free days corrected for sleep debt (MSFsc,r = −0.566) were significantly correlated with MEQ. The MEQ was further tested against MSF in four conditions of the split sleep pattern. The MSF modified for split sleep within 60 minutes after the first awakening showed highest correlation (r = −0.576) against MEQ score. The results demonstrate the modified version of MCTQ is valid to determine the chronotype in participants who practice consolidated and split sleep patterns.

The efficacy of add-on ramelteon and subsequent dose reduction in benzodiazepine derivatives/Z-drugs for the treatment of sleep-related eating disorder and night eating syndrome: a retrospective analysis of consecutive patients.

The objective of this study was to determine the efficacy of ramelteon in treating abnormal eating behavior in patients with sleep-related eating disorder and/or night eating syndrome. We retrospectively reviewed the medical records of patients with sleep-related eating disorder/night eating syndrome at the Yoyogi Sleep Disorder Center from November 2013 to November 2018. We categorized patients as ramelteon treatment responders when the frequency of nighttime eating per week decreased to less than half of that before treatment. Forty-nine patients were included in the analysis. The mean frequency of eating behavior (per week) (standard deviation) at baseline and post-ramelteon treatment was significantly different, at 5.3 (2.2) and 3.2 (3.0), respectively (P < .001). Twenty-one patients (42.9%) were classified as responders. Adverse events, all of which were mild daytime somnolence, were observed in 5 patients. There were significantly more individuals using benzodiazepine derivatives and Z-drugs before treatment and those with coexisting delayed sleep-wake phase disorder in the responder group than in the nonresponder group (P < .001 and P < .05, respectively). The mean benzodiazepine derivatives and Z-drugs dose significantly decreased from baseline to post-ramelteon treatment within the responder group (P < .05). This trend was not observed in the nonresponder group. Meanwhile, the sleep midpoint of patients with sleep-related eating disorder/night eating syndrome and delayed sleep-wake phase disorder did not significantly change after treatment. Our results indicate that ramelteon is a candidate treatment for sleep-related eating disorder/night eating syndrome. The effects of ramelteon might have occurred primarily through the reduction in benzodiazepine derivatives and Z-drugs rather than through the improvement in sleep-wake rhythm dysregulation.

Evaluation of the Consensus Sleep Diary in a community sample: comparison with single-channel electroencephalography, actigraphy, and retrospective questionnaire.

The Consensus Sleep Diary (CSD) was developed by experts to promote standardization of sleep diary data across the field, but studies comparing the CSD with other assessments of sleep parameters are scarce. This study compared the CSD with 3 other methods to assess sleep duration, efficiency, and timing. Participants (n = 80) were community adults (mean age = 32.65 years, 63% female) who completed the time-stamped CSD and used single-channel electroencephalography (EEG) and actigraphy for 7 days at home, then completed a retrospective sleep questionnaire. Total sleep time (TST), sleep efficiency (SE), and sleep midpoint were compared using correlations, Bland-Altman plots, and limits of agreement (adjusted for repeated measures). Correlations between the CSD and all methods on TST were large (rs = .63-.75). Adjusted CSD average TST was 40 minutes greater than with EEG and 31 minutes greater than with actigraphy. Correlations between CSD, actigraphy, and EEG for SE were small (rs = .18), and there was a medium correlation with questionnaire (r = .42). Adjusted CSD average SE was 7% greater than EEG and 6% greater than actigraphy; both demonstrated heteroscedasticity. Sleep midpoint correlations between CSD and all methods were large (r = .92-.99). Adjusted CSD was, on average, 6 minutes later than EEG and 1 minute later than actigraphy. Questionnaire-derived sleep parameters demonstrated nonconstant bias; lesser values had positive bias and greater values had negative bias. The time-stamped CSD led to meaningful overestimations of TST and SE as measured by objective/inferred methods. However, sleep timing was rather accurately assessed with the CSD in comparison to objective/inferred measures. Researchers should carefully consider which sleep assessment methods are best aligned with their research question and parameters of interest, as methods do not demonstrate complete agreement.

Differences between male and female university students in sleepiness, weekday sleep loss, and weekend sleep duration

IntroductionWomen and men experience sleep differently and the difference in intrinsic desire for sleep might underlie some of the observed male-female differences. The objective of this cross-sectional questionnaire study of university students was to determine male-female differences in self-reported sleepiness and sleep-wake patterns. MethodsFive questionnaires were completed by 1650 students at four Russian universities. ResultsCompared to male students, female students reported a lower subjective sleep quality score, had a higher morning sleepability score and lower nighttime and daytime wakeability scores. They more often reported excessive daytime sleepiness and expected to be sleepier at any time of the day with the largest male-female difference around the times of sleep onset and offset. On free days, they reported a longer sleep duration and an earlier sleep onset. Free-weekday difference was larger for sleep duration and smaller for sleep onset. Such male-female differences showed similarity to the differences observed in university and high school students from different countries around the globe. There was no significant male-female difference in weekly averaged sleep duration, weekday sleep duration, hours slept, midpoint of sleep on free days, free-weekday difference in sleep offset, social jetlag, and morningness-eveningness score. Therefore, when studies rely on these self-reports, the most salient male-female differences might not be immediately evident. ConclusionsIt seems that the intrinsic desire for longer sleep duration might contribute to a higher susceptibility of female students to weekday sleep loss. Among these students, negative effects of reduced sleep duration might be more common and more detrimental.

Genetic and environmental influences on sleep-wake behaviors in adolescence.

To investigate the influence of genetic and environmental factors on sleep-wake behaviors across adolescence. Four hundred and ninety-five participants (aged 9-17; 55% females), including 93 monozygotic and 117 dizygotic twin pairs, and 75 unmatched twins, wore an accelerometry device and completed a sleep diary for 2 weeks. Individual differences in sleep onset, wake time, and sleep midpoint were influenced by both additive genetic (44%-50% of total variance) and shared environmental (31%-42%) factors, with a predominant genetic influence for sleep duration (62%) and restorative sleep (43%). When stratified into younger (aged 9-14) and older (aged 16-17) subsamples, genetic sources were more prominent in older adolescents. The moderate correlation between sleep duration and midpoint (rP = -.43, rG = .54) was attributable to a common genetic source. Sleep-wake behaviors on school and nonschool nights were correlated (rP = .44-.72) and influenced by the same genetic and unique environmental factors. Genetic sources specific to night-type were also identified, for all behaviors except restorative sleep. There were strong genetic influences on sleep-wake phenotypes, particularly on sleep timing, in adolescence. Moreover, there may be common genetic influences underlying both sleep and circadian rhythms. The differences in sleep-wake behaviors on school and nonschool nights could be attributable to genetic factors involved in reactivity to environmental context.

Associations between 24-h sleep–wake patterns and cardiometabolic risk factors in youth seeking mental health care

One hundred and eleven youth with mental ill-health underwent systematic clinical, laboratory and actigraphy monitoring to report associations between 24-h sleep–wake patterns and cardiometabolic risk factors. Multiple linear regression analyses, controlling for medication usage and class, age and sex, found significant associations between: later sleep onset and BMI; standard variation (SV) in the sleep offset with both insulin values and the updated homeostatic model assessment of insulin resistance (HOMA2-IR) values; and the SV of the sleep midpoint with both poorer fasting insulin, and HOMA2-IR values. Further longitudinal research is required to determine the causative relationships between 24-h sleep–wake cycle patterns, and cardiometabolic outcomes.

Sleep habits and circadian preferences in school-aged children attending a Mexican double-shift school system

ObjectiveTo determine the differences between sleep habits and circadian preference in school-aged children attending a Mexican double-shift school system. MethodsThis cross-sectional study consisted of 400 elementary public-school children (mean age = 10.77, SD = 0.70 y, from fourth, fifth and sixth grades) in Reynosa, Tamaulipas, in northeastern Mexico. Attending a double-shift school system: 200 from the morning shift and 200 in the afternoon shift. Specific questions regarding sleep habits were collected and for circadian preference, the Morningness-Eveningness Scale for Children (MESC) was used. ResultsMultivariate analysis reported no sex differences. Children attending at the morning shift during weekdays rose earlier, reported shorter time in bed and earlier midpoint of sleep than those in the afternoon shift. On weekends, morning shift children went to bed later than afternoon shift. Morning shift reported greater social jetlag, shorter average sleep length and more sleep deficit than afternoon shift. During weekdays and weekends evening type children went to bed later, rose later and reported later midpoint of sleep. Also, evening type reported more social jetlag than morning types. ConclusionThis study suggests that early school start times can have a detrimental effect on Mexican children. Moreover, the morning shift children may be at more risk of poor health due to the higher social jetlag, as well as a higher tendency to be sleep deprived. On the other hand, the afternoon shift represents an important social environment that allows children to follow their natural physiological needs and a more optimal sleep health.

Sleep duration and timing are nonlinearly associated with depressive symptoms among older adults

BackgroundGeriatric depression is a common but preventable psychiatric disorder; however, its association with specific sleep patterns remains unclear. Therefore, we examined the association of self-reported sleep duration and sleep timing with depressive symptoms in the older population. MethodsA total of 1068 older Taiwanese adults (52.7% women; 72.2 ± 5.7 y) responded to a telephone survey during 2019–2020. Self-reported data on sociodemographic characteristics, sleep duration, bedtime, wake-up time (adapted items from Pittsburgh Sleep Quality Index), and depressive symptoms (five-item Center for Epidemiological Studies–Depression scale) were included. Generalized additive models were used to examine the nonlinear associations of sleep duration and midpoint sleep time (ie, the midpoint of bedtime and wake-up time) with depressive symptoms. ResultsThe means of sleep duration and midpoint sleep time in the participants were 6 h per night and 02:13 h, respectively. The results showed marked nonlinear associations of sleep patterns with depressive symptoms. Sleep duration shorter than 4 h per night was associated with a relatively higher level of depressive symptoms, with the highest risk (coefficient = 3.41; 95% confidence interval [CI] = 2.12, 4.70) while sleeping 2.06 h per night. The midpoint sleep time was positively associated with depressive symptom scores after 01:00 h. ConclusionsThe results showed that sleep duration and fitting sleep timing were nonlinearly associated with the risks of depressive symptoms in the general older adult population. These findings have implications for targeting nonpharmacological approaches by tackling modifiable behaviors, such as adequate sleep duration and timing, with decreased risks of depressive symptoms in the older adult population.

Genetic variants for morningness in relation to habitual sleep-wake behavior and diurnal preference in a population-based sample of 17,243 adults

ObjectiveAssociations of eveningness with health hazards benefit from analyzing to what extent the polygenic score for morningness correlates with the assessments of the behavioral trait of morningness-eveningness and chronotype. MethodsWith a population-based sample of 17,243 Finnish adults, aged 25–74 years, this study examines the associations of four feasible assessment methods of chronotype, a) biological the genetic liability based on the polygenic score for morningness (PGSmorn), b) the widely-used single item for self-assessed morningness/eveningness (MEQi19) of the original Morningness-Eveningness Questionnaire (MEQ), c) the behavioral trait of morningness-eveningness as assessed with the score on the shortened version (sMEQ) of the original MEQ, and d) the phase of entrainment as assessed with the habitual midpoint of sleep based on the self-reported sleep-wake schedule during weekend (Sleepmid-wknd) as well as the sleep debt corrected midpoint of sleep (Sleepmid-corr). ResultsAll self-report measures correlated with each other, but very weakly with the PGSmorn, which explained 1–2% of the variation in diurnal preference or habitual sleep-wake schedule. The influence of age was greater on Sleepmid-wknd and Sleepmid-corr than on the sMEQ or MEQi19, indicating that the diurnal preference might be a more stable indicator for morningness-eveningness than the sleep-wake schedule. Analyses of the discrepancies between sMEQ and MEQi19 indicated that eveningness can be over-estimated when relying on only the single-item self-assessment. ConclusionsThe current polygenic score for morningness explains only a small proportion of the variation in diurnal preference or habitual sleep-wake schedule. The molecular genetic basis for morningness-eveningness needs further elucidation.

The role of depressive symptoms and symptom dimensions in actigraphy-assessed sleep, circadian rhythm, and physical activity.

Considering the heterogeneity of depression, distinct depressive symptom dimensions may be differentially associated with more objective actigraphy-based estimates of physical activity (PA), sleep and circadian rhythm (CR). We examined the association between PA, sleep, and CR assessed with actigraphy and symptom dimensions (i.e. mood/cognition, somatic/vegetative, sleep). Fourteen-day actigraphy data of 359 participants were obtained from the Netherlands Study of Depression and Anxiety. PA, sleep, and CR estimates included gross motor activity (GMA), sleep duration (SD), sleep efficiency (SE), relative amplitude between daytime and night-time activity (RA) and sleep midpoint. The 30-item Inventory of Depressive Symptomatology was used to assess depressive symptoms, which were categorised in three depression dimensions: mood/cognition, somatic/vegetative, and sleep. GMA and RA were negatively associated with higher score on all three symptom dimensions: mood/cognition (GMA: β = -0.155, p < 0.001; RA: β = -0.116, p = 0.002), somatic/vegetative (GMA: β = -0.165, p < 0.001; RA: β = -0.133, p < 0.001), sleep (GMA: β = -0.169, p < 0.001; RA: β = -0.190, p < 0.001). The association with sleep was more pronounced for two depression dimensions: longer SD was linked to somatic/vegetative (β = 0.115, p = 0.015) dimension and lower SE was linked to sleep (β = -0.101, p = 0.011) dimension. As three symptom dimensions were associated with actigraphy-based low PA and dampened CR, these seem to be general indicators of depression. Sleep disturbances appeared more linked to the somatic/vegetative and sleep dimensions; the effectiveness of sleep interventions in patients reporting somatic/vegetative symptoms may be explored, as well as the potential of actigraphy to monitor treatment response to such interventions.

Association of chronotype as assessed by the midpoint of sleep with the dietary intake and health-related quality of life for elderly Japanese women.

The relationship of chronotype differences with dietary habits and health-related outcomes among elderly people is not fully understood, although sex and generation differences are observed in human chronotype. Accordingly, we analysed the association of chronotype (as assessed by the midpoint of sleep) with dietary intake and health-related quality of life (HRQoL) in elderly Japanese women. The subjects in this cross-sectional study were 1618 women aged 65 years and older who were grandmothers or acquaintances of dietetics students. The subjects were classified into quintiles with respect to the midpoint of sleep, from the earliest to the latest quintile. HRQoL was assessed by the Japanese version of the short-form 36-item health survey score. Mental health was assessed by the Center for Epidemiologic Studies Depression (CES-D) Scale. Dietary intake was assessed by a brief-type self-administered diet history questionnaire. A later midpoint of sleep was associated with a lower intake of vitamin D and a higher intake of bread and caffeinated drinks. No correlations were observed between chronotype and other nutrient and food intake. The subjects with a late midpoint of sleep (eveningness) showed poor general health perception (GH) and high CES-D scores. Other HRQoL scores did not differ among groups with different midpoints of sleep. In conclusion, chronotype as assessed by the midpoint of sleep is associated with poor GH and depressive tendencies in elderly Japanese women. Additionally, a few associations were found between dietary intake and chronotype in elderly Japanese women.