Sleep efficiency (but not sleep duration) of healthy school-age children is associated with grades in math and languages

ObjectiveThe objective of this study was to examine the associations between objective measures of sleep duration and sleep efficiency with the grades obtained by healthy typically developing children in math, language, science, and art while controlling for the potential confounding effects of socioeconomic status (SES), age, and gender.Study designWe studied healthy typically developing children between 7 and 11 years of age. Sleep was assessed for five week nights using actigraphy, and parents provided their child's most recent report card.ResultsHigher sleep efficiency (but not sleep duration) was associated with better grades in math, English language, and French as a second language, above and beyond the contributions of age, gender, and SES.ConclusionSleep efficiency, but not sleep duration, is associated with academic performance as measured by report-card grades in typically developing school-aged children. The integration of strategies to improve sleep efficiency might represent a successful approach for improving children's readiness and/or performance in math and languages.     

Sleep duration is associated with white matter microstructure and cognitive performance in healthy adults

Reduced sleep duration and sleep deprivation have been associated with cognitive impairment as well as decreased white matter integrity as reported by experimental studies. However, it is largely unknown whether differences in sleep duration and sleep quality might affect microstructural white matter and cognition. Therefore, the present study aims to examine the cross‐sectional relationship between sleep duration, sleep quality, and cognitive performance in a naturalistic study design, by focusing on the association with white matter integrity in a large sample of healthy, young adults. To address this, 1,065 participants, taken from the publicly available sample of the Human Connectome Project, underwent diffusion tensor imaging. Moreover, broad cognitive performance measures (NIH Cognition Toolbox) and sleep duration and quality (Pittsburgh Sleep Quality Index) were assessed. The results revealed a significant positive association between sleep duration and overall cognitive performance. Shorter sleep duration significantly correlated with fractional anisotropy (FA) reductions in the left superior longitudinal fasciculus (SLF). In turn, FA in this tract was related to measures of cognitive performance and was shown to significantly mediate the association of sleep duration and cognition. For cognition only, associations shift to a negative association of sleep duration and cognition for participants sleeping more than 8 hr a day. Investigations into subjective sleep quality showed no such associations. The present study showed that real‐world differences in sleep duration, but not subjective sleep quality are related to cognitive performance measures and white matter integrity in the SLF in healthy, young adults.     

Sensorimotor performance in school-age children with autism, developmental language disorder, or low IQ

The purpose of the study was to determine the prevalence of 'soft' motor deficits in school-aged children with either developmental language disorder (DLD), autism (with high IQ [HiAD] or low IQ [LoAD]), or low IQ without autism (LoIQ), and to evaluate the utility of a refined neurological examination to discriminate between these groups. A total of 242 children (74% male), aged 7 or 9 years, were evaluated as part of a longitudinal, multi-institutional study, with a standardized neurological examination that included Denckla's Physical and Neurological Examination for Soft Signs. Most of the scores separated children into two groups defined by nonverbal IQ, with the DLD and HiAD groups performing better than the LoAD and LoIQ groups. Exceptions included motor impersistence and stereotypies, which were more likely in the autistic groups. The neurologists' summary clinical impressions indicated better sensory/motor skills, oromotor skills, and praxis in the HiAD than in the DLD children. Inability/unwillingness to perform tasks was much more frequent in LoAD than LoIQ children.     

Poor sleep quality is associated with worse self-rated health in long sleep duration but not short sleep duration

Unhealthy sleep duration, either short or long, is associated with worse health and central subjective dimensions of sleep and health such as fatigue. It has been argued that the link between sleep duration and health may depend on the quality of the slept hours, and on its functional impact (ie, fatigue). The present study therefore assessed whether the relationship between last night's sleep duration and general self-rated health (SRH) differs as a function of sleep quality, and secondly, whether current fatigue and sleep quality are factors linking sleep duration and SRH.The present cross-sectional dataset involved 1304 individuals (57% female, M_age = 28.8, range 18–79). Participants completed surveys for general SRH, previous night's sleep duration and sleep quality, and current fatigue.Results showed the expected inverted U-shaped (ie, quadratic) relation between last night's sleep duration and SRH and a linear relation between last night's sleep quality and SRH. However, long sleep duration was only associated with poorer SRH in individuals who also reported poor sleep quality. Further, the quadratic relationship between sleep duration and SRH was partially mediated by fatigue and sleep quality.The results of this multi-study analysis suggest that SRH is particularly poor in those who slept both long and with poor quality the night before, while good sleep quality may protect those with a long sleep duration from poor SRH. Thus, last night's long sleep does not seem to be associated with poor subjective health unless it is coupled with poor sleep quality. Furthermore, fatigue and sleep quality are potential pathways linking short and long sleep duration with SRH. Different dimensions of sleep interact in their association with health, and future research will benefit from an integrative approach.     

School-based sleep education program improves sleep and academic performance of school-age children

Study objectiveThe objective of this study was to develop and evaluate the effectiveness of a school-based sleep education program aimed at improving the sleep and academic performance of school-age children.MethodsUsing a community-based participatory research approach, we created a school-based sleep education program, “Sleep for Success”™ (SFS), composed of four distinct modules that addressed the children, their family and community, the school staff, and decision makers within the school setting. Implementation was carried out in three elementary schools. Seventy-one students participated in the evaluation of the program. The effectiveness of the SFS program was evaluated using non-randomized controlled before-and-after study groups (intervention and control) assessed over two time points (pre- and post-program implementation). Before (baseline) and after implementation, sleep and academic performance were measured using actigraphy and report card marks, respectively.ResultsIn the intervention group, true sleep was extended by 18.2 min per night, sleep efficiency improved by 2.3%, and sleep latency was shortened by 2.3 min, and report card grades in mathematics and English improved significantly. No changes were noted in the control group.ConclusionParticipation in the sleep education program was associated with significant improvements in children's sleep and academic performance.     

Allostatic load in early pregnancy is associated with poor sleep quality

BackgroundAllostatic load (AL) measures the cumulative impact of chronic stress and is associated with adverse health outcomes. A novel scoring system has previously been developed for AL in early pregnancy that is associated with pre-eclampsia. It was hypothesized that AL, as identified by the present model, is associated with psychosocial stressors and, specifically, poor sleep quality.MethodsWomen were selected from a low-risk, community-dwelling study population who enrolled at <15 weeks gestation. Nine physiologic components were divided among the domains of cardiovascular, metabolic, and inflammatory function. Spearman's rank correlations were used to examine the association of AL with age, income, the Revised Prenatal Distress Questionnaire (NuPDQ), Inventory of Depressive Symptoms (IDS), and Pittsburgh Sleep Quality Index (PSQI). The Wilcoxon rank-sum test was used to compare AL by race and educational attainment.ResultsA total of 103 women were identified, with: a mean age of 29.8 ± 5.0 years, 17.5% black, and mean gestational age 12.2 ± 1.1 weeks. Allostatic load was positively correlated with the PSQI (ρ = 0.23, p = 0.018). There were no associations with age, income, prenatal distress, race, or depression scores. College-educated women had lower AL compared with those with less education (0.57 ± 0.43 vs 0.81 ± 0.55, p = 0.045).ConclusionHigher AL, measured by the pregnancy-specific model, was associated with poorer sleep quality and lower educational attainment, both of which were considered to be chronic stressors. These relationships were consistent with previous findings in non-pregnant populations, and suggest that AL may be useful for capturing the physiologic impact of chronic stress in early pregnancy.     

Childhood abuse is associated with stress-related sleep disturbance and poor sleep quality in pregnancy

ObjectivesChildhood abuse is associated with increased risks of adult psychiatric disorders and physical health conditions. Mounting evidence documents associations of childhood abuse with sleep disturbances in adulthood. However, to date, no study has evaluated associations of childhood abuse and sleep disturbances among pregnant women.MethodsThis cross-sectional study included 634 pregnant Peruvian women. To collect information regarding socio-demographic characteristics, history of childhood abuse, and complaints of sleep disturbances, face-to-face interviews were conducted with women in early pregnancy. Ford Insomnia Response to Stress Test (FIRST-S) and the Pittsburgh Sleep Quality Index (PSQI-S), translated from English to Spanish, were used to assess stress-related sleep disturbance and sleep quality, respectively. Logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95% CIs).ResultsWomen who experienced any childhood abuse had a 1.65-fold increased odds of stress-related sleep disturbance (aOR = 1.65; 95% CI: 1.15–2.38) and 2.11-fold increased odds of poor sleep quality during early pregnancy (aOR = 2.11; 95% CI: 1.35–3.30) as compared with women who reported no abuse. Women who reported both physical and sexual abuse during childhood were more than twice as likely to suffer from stress-related sleep disturbance (aOR = 2.26; 95% CI: 1.44–3.53) and poor sleep quality (aOR = 2.43; 95% CI: 1.45–4.09) in comparison to women who reported no childhood abuse.ConclusionsA history of childhood abuse is associated with increased odds of stress-related sleep disturbance and poor sleep quality during pregnancy. These findings, if replicated, should be used to inform the development of trauma-informed care for such sleep disturbances induced by childhood trauma.     

Risk factors associated with short sleep duration among Chinese school-aged children

ObjectivesTo examine risk factors regarding short sleep duration among Chinese school-aged children.MethodsA random sample of 20,778 children aged around 5–11 years participated in a cross-sectional survey, which was conducted in eight cities of China in 2005. A parent-administered questionnaire was used to collect information on children’s sleep duration and possible related factors from eight domains. Short sleep duration was defined as total sleep duration <9 h per day.ResultsIn all, 28.3% of the sampled children slept <9 h per day. The multivariate logistic regression identified, after adjusting for demographic and socioeconomic variables, factors associated with short sleep duration: more television viewing during weekdays (OR = 1.21, p = 0.004), more frequent computer/internet using (OR = 1.17, p = 0.006), earlier school starting time (OR = 1.10, p = 0.020), more time on homework during weekdays (OR = 1.66, p < 0.001) and weekends (OR = 1.14, p = 0.001), poor bedtime hygiene (e.g., having drinks with caffeine after 6:00PM [OR = 1.22, p < 0.001], doing exciting activities during bedtime [OR = 1.16, p < 0.001], and irregular bedtime [OR = 1.55, p < 0.001]), and shorter sleep duration of parents (mother: OR = 1.31, p < 0.001 for sleep duration <6 h and OR = 1.24, p = 0.006 for 6–8 h; father: OR = 1.52, p < 0.001 for <6 h and OR = 1.19, p < 0.001 for 6–8 h).ConclusionsFactors associated with sleep duration covered multidimensional domains among school-aged children. Compared to sleep environments and chronic health problems, school schedules, lifestyle patterns, and parents’ sleep habits had greater impact on children’s sleep duration, indicating the existing chronic sleep loss in school children could be, at least partly, intervened by reducing the use of visual technologies, by changing the school schedules, by improving the sleep hygiene routine, and by regulating parents’ sleep habits.     

Habitual sleep variability,not sleep duration,is associated with caloric intake in adolescents

ObjectiveThe objective of this study was to investigate the associations between objectively measured habitual sleep duration (HSD), habitual sleep variability (HSV), and energy and snack intake in adolescents.MethodsWe used data from 324 adolescents who participated in the Penn State Child Cohort follow-up examination. Actigraphy was used over seven consecutive nights to estimate nightly sleep duration. The seven-night mean and standard deviation of sleep duration were used to represent HSD and HSV, respectively. The Youth/Adolescent Food Frequency Questionnaire was used to obtain the daily average total energy, protein, fat, and carbohydrate intake, and number of snacks consumed. Linear regression models were used to investigate the associations between habitual sleep patterns and caloric, protein, fat, and carbohydrate intake. Proportional odds models were used to associate habitual sleep patterns with snack consumption.ResultsAfter adjusting for age, sex, race, body mass index (BMI) percentile, and smoking status, an increased HSV was associated with a higher energy intake, particularly from fat and carbohydrate. For example, with a 1-h increase in HSV, there was a 170 (66)-kcal increase in the daily total energy intake. An increased HSV was also related to increased snack consumption, especially snacks consumed after dinner. For instance, a 1-h increase in HSV was associated with 65% and 94% higher odds of consuming more snacks after dinner during school/workdays and weekends/vacation days, respectively. Neither energy intake nor snack consumption was significantly related to HSD.ConclusionHigh habitual sleep variability, not habitual sleep duration, is related to increased energy and food consumption in adolescents. Maintaining a regular sleep pattern may decrease the risk of obesity in adolescents.     

Sleep duration rather than sleep timing is associated with obesity in adolescents

ObjectiveIn this study, we investigated differences in sleep patterns between obese and non-obese adolescents, and determined which sleep-related parameters were associated with a risk of adolescent obesity.MethodsIn this cross-sectional study, we evaluated 22,906 adolescents between 12 and 18 years of age (mean 15.2 ± 1.7 years; male 50.9%). Self-report questionnaires were used to assess body mass index (BMI) and sleep habits. Obesity was defined as a BMI-for-age ≥ 95th percentile. Weekend catch-up sleep (CUS) duration was calculated as the sleep duration on free days minus sleep duration on school days. We estimated mid-sleep time on free days corrected for oversleep on free days (MSFsc) and social jet lag. Then, we performed multivariate analysis for adolescent obesity and BMI, respectively.ResultsThe prevalence of obesity was 6.0%. The average sleep duration (P = 0.017) and weekend CUS duration (P < 0.001) of obese adolescents were shorter than those of non-obese adolescents. However, there was no significant difference in MSFsc or social jet lag by the obesity status. After adjustment, obesity was significantly associated with short average sleep duration (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.86–0.96) and short weekend CUS duration (OR 0.92, 95% CI 0.89–0.95). Similarly, BMI was inversely correlated with average sleep duration (B = −0.15, 95% CI -0.19 to −0.11) and weekend CUS duration (B = −0.09, 95% CI -0.11 to −0.06).ConclusionsOur observations suggest that short sleep duration, rather than late MSFsc or social jet lag, was associated with adolescent obesity.     

Characteristics associated with parental estimates of sleep duration in children with autism spectrum disorders

BackgroundSleep problems are common in individuals with ASD. This study examined the relationships between bedtime consistency, cognitive functioning, comorbid diagnoses, intervention, demographics and sleep duration in children with ASD.MethodCross-sectional data from 1683 children with ASD in the 2016 and 2017 National Survey of Children's Health were analyzed. The sample was 80 % male, 46 % non-Hispanic white, and mean age was 10.5 (SD 4.1) years. All data were parent report. Multiple linear regression was performed.ResultsASD severity was associated with shorter sleep duration, and bedtime consistency was associated with longer sleep duration. Age moderated the effects of both bedtime consistency and ADD/ADHD on sleep duration. Both the positive effect of bedtime consistency and the negative effect of ADD/ADHD on sleep duration became less pronounced with age.ConclusionAlthough the challenges related to sleep and behavior may differ by age of the child, bedtime consistency could be a good target to improve sleep duration for all children with ASD. Future studies, especially longitudinal studies, on sleep habits and sleep hygiene, in conjunction with other measures of sleep patterns (e.g., night wakings) and correlates of sleep problems, may provide further evidence for the importance of good sleep practices and guide sleep treatment in children with ASD.     

Short sleep duration is associated with B-type natriuretic peptide levels and predicts the death of Japanese patients with type 2 diabetes

ObjectiveTo investigate the associations of sleep duration with all-cause mortality, glycemic control, and other clinical parameters of patients with type 2 diabetes.MethodsFrom April 2013 to December 2015, we conducted a retrospective cohort study. Study participants were divided into three groups according to their sleep duration. Multiple regression analysis and Cox proportional hazards analysis were performed to assess the independent associations of sleep duration with clinical parameters and all-cause mortality.ResultsWe enrolled 1233 patients who were then followed for 860 ± 264 days. During the follow-up period, 20 patients (1.6%) died. Sleep duration inversely associated with plasma B-type natriuretic peptide levels (β = −0.203, p = 0.012) in short (<7 h) sleepers, whereas it was positively associated with hemoglobin A1c levels (β = 0.156, p = 0.021) in long (≥9 h) sleepers. Moreover, Cox proportional hazard analysis revealed that short sleep duration was a significant predictor of all-cause mortality (hazard ratio = 0.473; confidence interval 0.248–0.905, p = 0.024).ConclusionShort sleep duration may serve as a prognostic indicator of mortality in Japanese patients with type 2 diabetes and may increase cardiovascular stress. Adequate sleep is essential for the management of type 2 diabetes.     

Shorter REM latency associated with more sleep cycles of a shorter duration in healthy humans

A significant association between rapid eye movement (REM) sleep latency and the number of non-REM/REM sleep cycles was found 15 years ago in a large retrospective study. The present prospective study further explored this intra-sleep relationship and analyzed the links between these two variables and the mean cycle duration. It was based on a carefully selected group of healthy control subjects whose sleep was polysomnographically recorded at home for 4 sequential nights. The latency of REM sleep was inversely correlated with the number of cycles and positively correlated with the mean cycle duration, both in individual nights and on means of 4 nights. The present study demonstrated that variations in the number of cycles or the mean cycle duration between the nights are far less important than the substantial differences observed between subjects. Present outcomes support the study of sleep cycle periods and frequencies in those psychiatric disorders where REM sleep latencies have been found to be shorter, and they suggest that these variables be included in sleep studies in which cycles are compared with each other.     

Blunted hypothalamo-pituitary-adrenal axis reactivity is associated with the poor intelligence performance in children with attention-deficit/hyperactivity disorder

The aim of the present study was to examine the effects of hypothalamo-pituitary-adrenal (HPA) axis reactivity on intelligence test performance in subjects with attention-deficit/hyperactivity disorder (ADHD). We investigated the extent to which an increase or decrease in cortisol after stress was associated with the intelligence test performance in 68 clinic-referred children with ADHD. The mean age of the participants was 8.8 years; 54 of the 68 participants were boys and 14 were girls. ADHD was diagnosed using the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). Psychological tests, including the Wechsler Intelligence Scale for Children-III and the ADHD diagnostic system (ADS), were administered as a stressor. A saliva sample was collected from each subject before and after psychological testing in order to measure the level of cortisol in the saliva. The cortisol level was measured using a solid-phase radioimmunoassay. Fifty-one of the 68 subjects showed no increase in the level of cortisol after the test. Decreases in the level of cortisol after the test were correlated with poor intelligence performance and the decrease of cortisol in respect to baseline significantly affected the verbal, performance and total IQ (effect sizes, 7.4-9.5%) in subjects who showed blunted responses to stress.     

Self-reported nocturnal sleep duration is associated with next-day resting state functional connectivity

Sleep deprivation affects cerebral metabolism and reduces the functional connectivity among various regions of the brain, potentially explaining some of the associated mood and emotional changes often observed. Prior neuroimaging studies have only examined the effects of sleep deprivation or partial sleep restriction on functional connectivity, but none have studied how such connectivity is associated with normal variations in self-reported sleep duration the night before the scan. We examined the relationship between sleep duration and resting state functional connectivity among healthy volunteers who slept at home according to their own schedules. Thirty-nine healthy individuals aged 18-45 (21 females) completed a questionnaire asking about their recent sleep habits and entries in their sleep diary for the previous night, followed by resting state functional MRI at 3 T. Participants reported sleeping between 5.0 and 8.5 h the night before the scan (M=7.0, SD=0.9). Seed regions were placed in the medial prefrontal cortex and posterior cingulate cortex nodes of the default mode network, regions previously implicated in sleep deprivation. Longer self-reported sleep duration was associated with significantly enhanced functional connectivity between the medial prefrontal cortex and posterior cingulate, as well as greater anticorrelations with parietal, occipital, and lateral prefrontal regions. Findings suggest that even normal variations in sleep duration measured by self-report are related to the strength of functional connectivity within select nodes of the default mode network and its anticorrelated network.     

Time for bed! Earlier sleep onset is associated with longer nighttime sleep duration during infancy

Objective/backgroundClinical recommendations include putting infants to bed using a consistent bedtime routine at an appropriate hour to promote longer nighttime sleep. Actigraphy was used in this exploratory study to examine how bedtime routines and nighttime sleep onset were associated with nighttime total sleep time (TST) and efficiency from 6 to 24 weeks of age.Patients/methodsInfants (n = 24) wore sleep actigraphs for three, one-week periods at 6, 15, and 24 weeks of age. Nighttime TST, sleep efficiency, sleep onset and offset were quantified. Mothers reported on infant bedtime routines using the Brief Infant Sleep Questionnaire at each age. Multilevel models examined between- and within-person associations.ResultsAs infants aged, sleep onset was earlier, and bedtime routines became shorter (p's < 0.05). Infants fell asleep between 7 and 8:00PM on 24% of the nights. Most mothers (70%) reported that they often fed infants to sleep for the night. For every 1 h earlier in infants' usual sleep onset, nighttime TST was 34.4 min longer that night (p < 0.01). Infants with earlier than usual sleep onset had slightly earlier sleep offset the next morning (8.4 min for every 1 h earlier in onset; p = 0.02). Between-person analyses showed similar patterns. Infants with a more consistent bedtime routine and who were not typically fed to sleep at bedtime had longer nighttime TST at 6 weeks, with a trend or no association at later ages.ConclusionInfants who fell asleep earlier also slept longer at night. Keeping infants up later in hopes of them sleeping in longer may be counterproductive.     

Shorter sleep duration is associated with lower GABA levels in the anterior cingulate cortex

BackgroundAlterations in the levels of gamma-aminobutyric acid (GABA) and glutamate + glutamine (Glx), which are major inhibitory and excitatory neurotransmitters, respectively, are frequently associated with insomnia. Previous reports also suggested the involvement of the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) in insomnia and shorter sleep duration. In the current study, we investigated whether the GABA and Glx levels were altered in the ACC/mPFC in subclinical insomnia while focusing on the sleep duration.MethodsWe examined levels of GABA and Glx in the ACC/mPFC of the brain with magnetic resonance spectroscopy in 166 individuals with subjective sleep complaints but without a diagnosis of insomnia. Participants were divided into two groups according to sleep duration (≥6 h/night: n = 79 vs. < 6 h/night: n = 74), which was measured using a wrist-worn actigraphy. Working memory function and overall subjective sleep quality were assessed with a computerized neuropsychological test and self-report questionnaire, respectively.ResultsGABA levels in the ACC/mPFC were lower in the shorter sleep duration group relative to the longer sleep duration group (t = −2.21, p = 0.03). Glx levels did not differ between the two groups (t = −0.20, p = 0.84). Lower GABA levels were associated with lower spatial working memory performance in the shorter sleep duration group (β = −0.21, p = 0.03), but not the longer sleep duration group (β = 0.04, p = 0.72).ConclusionShorter sleep duration was associated with lower GABA levels in the ACC/mPFC. These findings may provide insight into the underlying mechanisms of impaired working memory function related to insomnia and sleep loss.     

QT interval duration in apparently healthy men is associated with depression-related personality trait neuroticism

OBJECTIVE: High levels of neuroticism and low self-esteem are markers for vulnerability to depression, a condition associated with a higher risk of arrhythmias. The question as to whether these depression-related personality domains are related to cardiac repolarization (duration of QT interval) in apparently healthy men has been addressed in this study. METHODS: Participants were 658 clinically healthy males who underwent a health screening programme. QT interval duration was determined in the resting 12-lead electrocardiogram using an automated analysis program. Neuroticism was assessed by the short-scale Eysenck Personality Questionnaire and self-esteem by the Rosenberg self-esteem scale. RESULTS: Heart-rate corrected QT interval {QTc, formula of Bazett [Bazett HC. An analysis of time relations of electrocardiograms. Heart 1920;7:353-370]} progressively increased across quartiles of neuroticism ratings. By contrast, no differences in QTc were observed across different degrees of self-esteem. A multivariate regression analysis showed that neuroticism was a statistically significant, independent predictor of QTc duration. CONCLUSION: After adjustment for potential confounders, neuroticism scores independently predicted QT interval duration in apparently healthy men. These findings highlight the possibility that higher arrhythmic risk could be present not only in patients with clinical depression but also in depression-prone, otherwise healthy individuals.