Rapid eye movement sleep in relation to overweight in children and adolescents

Weight Status, Autonomic Function, and Systemic Inflammation in Children with Obstructive Sleep Apnea

Children with obstructive sleep apnea (OSA) frequently experience chronic low-grade systemic inflammation, with the inflammasome playing a central role in OSA. This cross-sectional study evaluated the relationship between weight status, autonomic function, and systemic inflammation in a cohort of 55 children with OSA, predominantly boys (78%) with an average age of 7.4 ± 2.2 years and an apnea-hypopnea index of 14.12 ± 17.05 events/hour. Measurements were taken of body mass index (BMI), sleep heart-rate variability, morning circulatory levels of interleukin-1β, interleukin-1 receptor antagonist, and interleukin-6, and tumor necrosis factor-α, anthropometry, and polysomnography. Multiple linear regression modeling showed that an apnea-hypopnea index was significantly associated with BMI, the standard deviation of successive differences between normal-to-normal intervals during N3 sleep, and the proportion of normal-to-normal interval pairs differing by more than 50 ms during rapid-eye-movement sleep. A moderated mediation model revealed that interleukin-1 receptor antagonist levels mediated the association between BMI and interleukin-6 levels, with sympathovagal balance during N3 sleep and minimum blood oxygen saturation further moderating these relationships. This study highlights the complex relationships between BMI, polysomnographic parameters, sleep heart-rate-variability metrics, and inflammatory markers in children with OSA, underlining the importance of weight management in this context.

Modifiable lifestyle risk factors for overweight and obesity in children and adolescents with type 1 diabetes: A systematic review

This review aims to identify and report epidemiological associations between modifiable lifestyle risk factors for overweight or obesity in children and adolescents with type 1 diabetes (T1D). A systematic literature search of medical databases from 1990 to 2023 was undertaken. Inclusion criteria were observational studies reporting on associations between dietary factors, disordered eating, physical activity, sedentary and sleep behaviours and measures of adiposity in children and adolescents (<18 years) with T1D. Thirty-seven studies met inclusion criteria. Studies were mostly cross-sectional (89 %), and 13 studies included adolescents up to 19 years which were included in this analysis. In adolescents with T1D, higher adiposity was positively associated with disordered eating behaviours (DEB) and a higher than recommended total fat and lower carbohydrate intake. A small amount of evidence suggested a positive association with skipping meals, and negative associations with diet quality and sleep stage. There were no published associations between overweight and physical activity, sedentary behaviours and eating disorders. Overall, the findings infer relationships between DEB, fat and carbohydrate intake and adiposity outcomes in people with T1D. Prospective studies are needed to determine causal relationships and to investigate sleep stages. High quality studies objectively measuring physical activity and include body composition outcomes are needed.

Effects of Early Wake-Up Time on Obesity in Adolescents

Background: Although numerous studies have reported that obesity in adolescents is related to shorter sleep duration, few studies have reported the effect of sleep timing, particularly early wake-up time, on obesity. Objectives: To investigate the association between wake-up time and adolescent obesity. Methods: Using the Korean National Health and Nutrition Examination Survey VII data, 1301 middle school and high school students were selected and grouped according to BMI. Sleep timing and lifestyle factors were evaluated using self-reported questionnaires. Results: The mean bedtime and wake-up time were 00:09 am and 07:06 am, respectively. Despite similar bedtimes, the group with overweight/obesity woke up earlier than the group with underweight/normal weight. The BMI z-score and the overweight/obesity relative risk decreased as the wake-up time was delayed, even after adjustment for covariates. Participants who woke up before 06:50 am had a 1.82-fold higher risk of having overweight/obesity than those who woke up after 07:30 am. Participants who woke up late tended to sleep longer than those who woke up early. Conclusions: Waking up early is significantly associated with an increased BMI z-score in adolescents and may be a risk factor for overweight/obesity.

The relationship between multiple sleep dimensions and obesity in adolescents: A systematic review

Sleep is an involuntary behaviour, biologically fundamental to survival and wellbeing. However, sleep is increasingly neglected, with significant health implications. Recent research has identified associations between sleep duration, quality, timing and risk of overweight/obesity in children and adults. The aim of this review was to systematically identify and examine research that investigates the relationships between multiple objective and subjective sleep outcomes and objective adiposity measures in adolescents. A systematic review of literature, published to December 2022, was conducted using ten bibliographic databases. Search terms included objective and subjective sleep/circadian rhythm outcomes, objective adiposity measurements, and adolescents aged 8-18 years. Eighty-nine studies were included in the final review. Sleep outcomes were synthesized into three sleep domains: pre-sleep, during sleep and post-sleep outcomes. In summary, pre-sleep outcomes (including poor sleep hygiene, later chronotype and increased variability and later sleep timings) and increased sleep disturbance are consistently significantly associated with increased obesity and adiposity in adolescents. The relationship between during-sleep outcomes (sleep quality and efficiency) with adiposity and obesity measures was mixed. These findings suggest that adapting an individual's schedule to best suit chronotype preference and improving sleep hygiene, including a consistent bedtime routine, could reduce adiposity and obesity in adolescents.

REM Sleep Loss-Induced Elevated Noradrenaline Plays a Significant Role in Neurodegeneration: Synthesis of Findings to Propose a Possible Mechanism of Action from Molecule to Patho-Physiological Changes

Wear and tear are natural processes for all living and non-living bodies. All living cells and organisms are metabolically active to generate energy for their routine needs, including for survival. In the process, the cells are exposed to oxidative load, metabolic waste, and bye-products. In an organ, the living non-neuronal cells divide and replenish the lost or damaged cells; however, as neuronal cells normally do not divide, they need special feature(s) for their protection, survival, and sustenance for normal functioning of the brain. The neurons grow and branch as axons and dendrites, which contribute to the formation of synapses with near and far neurons, the basic scaffold for complex brain functions. It is necessary that one or more basic and instinct physiological process(es) (functions) is likely to contribute to the protection of the neurons and maintenance of the synapses. It is known that rapid eye movement sleep (REMS), an autonomic instinct behavior, maintains brain functioning including learning and memory and its loss causes dysfunctions. In this review we correlate the role of REMS and its loss in synaptogenesis, memory consolidation, and neuronal degeneration. Further, as a mechanism of action, we will show that REMS maintains noradrenaline (NA) at a low level, which protects neurons from oxidative damage and maintains neuronal growth and synaptogenesis. However, upon REMS loss, the level of NA increases, which withdraws protection and causes apoptosis and loss of synapses and neurons. We propose that the latter possibly causes REMS loss associated neurodegenerative diseases and associated symptoms.

Development and Psychometric Properties of the Sleep Parenting Scale for Infants

Although infants' sleep behaviors are shaped by their interactions with parents at bedtime, few tools exist to capture parents' sleep parenting practices. This study developed a Sleep Parenting Scale for Infants (SPS-I) and aimed to (1) explore and validate its factorial structure, (2) examine its measurement invariance across mothers and fathers, and (3) investigate its reliability and concurrent and convergent validity. SPS-I was developed via a combination of items modified from existing scales and the development of novel items. Participants included 188 mothers and 152 mother-father dyads resulting in 340 mothers and 152 fathers; about half were non-Hispanic white. Mothers and fathers completed a 14-item SPS-I for their 12-month-old infant. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to explore and validate SPS-I's underlying structure. Multigroup CFA was used to examine measurement invariance across mothers and fathers. Reliability was examined using Cronbach's alpha. Concurrent validity was assessed using linear regressions examining associations between SPS-I factors and parent-reported infants nighttime sleep duration. Convergent validity was assessed using paired-sample t-tests to test whether the SPS-I subscale scores were similar between mothers and fathers in the same household. EFA and CFA confirmed a 3-factor, 12-item model: sleep routines, sleep autonomy, and screen media in the sleep environment. SPS-I was invariant across mothers and fathers and was reliable. Concurrent and convergent validity were established. SPS-I has good psychometric properties, supporting its use for characterizing sleep routines, sleep autonomy, and screen media in the sleep environment by mothers and fathers.Supplemental data for this article is available online at https://doi.org/10.1080/08964289.2021.2002799 .

[Research progress on correlation between childhood obesity and obstructive sleep apnea]

Prevalence of childhood obesity is progressively increasing, reaching worldwide levels of 5.6% in girls and of 7.8% in boys. This also leads to a corresponding increase in the prevalence of obesity-associated morbidities particularly those involving obstructive sleep apnea（OSA）. Obesity is an independent risk factor and regulator of OSA in children. There is a bidirectional causal relationship between OSA and obesity in children. The factors involved in the association between OSA and obesity are systemic inflammation, oxidative stress, and gut microbiota etc. However, a causal link between obesity-related inflammatory state and OSA pathogenesis still needs to be properly confirmed. The present review aimed to investigate the links between childhood obesity and OSA.

Associations between sleep, obesity, and asthma in urban minority children

STUDY OBJECTIVES

Although obesity, asthma, and sleep-disordered breathing are interrelated, there is limited understanding of the independent contributions of body-mass index and pulmonary function on polysomnography in children with asthma.

METHODS

We conducted a retrospective chart review on 448 7- to 18-year-old children with asthma who had undergone polysomnography testing between 1/2007-12/2011 to elucidate the association between spirometry variables, body-mass index, and polysomnography parameters, adjusting for asthma and antiallergic medications.

RESULTS

Obese children had poorer sleep architecture and more severe gas exchange abnormalities compared to healthy weight children. Multivariate analysis revealed an independent association of body-mass index with sleep efficiency, with more light and less deep sleep in both obese and healthy-weight children, and with baseline oxygen saturation and oxygen nadir in obese children. In obese children, forced vital capacity was independently associated with less deep sleep (time in N3 sleep) as well as with oxygen nadir, while among healthy-weight children, forced expiratory volume directly correlated but forced vital capacity inversely correlated with deep sleep. In obese children, inhaled corticosteroid was associated with baseline oxygen saturation, and montelukast was associated with lower end-tidal carbon dioxide. In healthy-weight children, inhaled corticosteroid was associated with arousal awakening index, and montelukast was associated with light sleep. Antiallergic medications were not independently associated with polysomnography parameters.

CONCLUSIONS

Pulmonary function, body-mass index, and asthma medications have independent and differing influences on sleep architecture and gas exchange polysomnography parameters in obese and healthy-weight children with asthma. Asthma medications are associated with improved gas exchange in obese children and improved sleep architecture in healthy-weight children with asthma.

CITATION

Conrad LA, Nandalike K, Rani S, Rastogi D. Associations between sleep, obesity, and asthma in urban minority children. J Clin Sleep Med. 2022;18(10):2377-2385.

Healthy Sleep Every Day Keeps the Doctor Away

When one considers the big picture of their health, sufficient sleep may often go overlooked as a keystone element in this picture. Insufficient sleep in either quality or duration is a growing problem for our modern society. It is essential to look at what this means for our health because insufficient sleep increases our risks of innumerable lifechanging diseases. Beyond increasing the risk of developing these diseases, it also makes the symptoms and pathogenesis of many diseases worse. Additionally, consistent quality sleep can not only improve our physical health but has also been shown to improve mental health and overall quality of life. Substandard sleep health could be a root cause for numerous issues individuals may be facing in their lives. It is essential that physicians take the time to learn about how to educate their patients on sleep health and try to work with them on an individual level to help motivate lifestyle changes. Facilitating access to sleep education for their patients is one way in which physicians can help provide patients with the tools to improve their sleep health. Throughout this paper, we will review the mechanisms behind the relationship between insufficient sleep health and chronic disease and what the science says about how inadequate sleep health negatively impacts the overall health and the quality of our lives. We will also explain the lifechanging effects of sufficient sleep and how we can help patients get there.

Characterization of rapid weight gain phenotype in children with narcolepsy

OBJECTIVES

To characterize the rapid weight gain (RWG) phenotype associated with the onset of childhood narcolepsy and to determine whether it could constitute a marker of severity of the disease.

METHODS

RWG was defined using the BMI z-score slope reported to one year (>0.67 SD) from symptom onset to disease diagnosis. We compared the clinical, metabolic, and sleep characteristics between patients with or without RWG at diagnosis. Pharmacological management, anthropometric, and clinical progression were also evaluated during the follow-up.

RESULTS

A total of 84 de novo narcoleptic pediatric patients were included; their median age at diagnosis was 12.0 years; 59.5% boys, 90.5% cataplexy, and 98.7% HLA-DQB1*06:02, 57% had RWG profile. RWG patients were younger at diagnosis than non-RWG patients, despite a shorter diagnostic delay. They had a higher BMI z-score and a higher prevalence of obesity at diagnosis, but not at symptom onset, and higher adapted Epworth Sleepiness Scale and Insomnia Severity Index scores than non-RWG patients. No differences on nocturnal polysomnography and multiple sleep latency tests were found between groups at disease diagnosis. After a median follow-up of 5 years, RWG patients still had a higher BMI z-score and a higher prevalence of obesity despite benefiting from the same therapeutic management and displaying improvement in sleepiness and school difficulties.

CONCLUSIONS

Narcoleptic RWG patients were younger, sleepier, and the prevalence of obesity was higher at diagnosis despite a shorter diagnostic delay than that of non-RWG patients. These patients had also a higher risk of developing a long-term obesity, despite a positive progression of their narcoleptic symptoms. RGW could then represent a maker of a more severe phenotype of childhood narcolepsy, which should inspire a prompt and more offensive management to prevent obesity and its complications.

Sleep Quality: A Narrative Review on Nutrition, Stimulants, and Physical Activity as Important Factors

Sleep is a cyclically occurring, transient, and functional state that is controlled primarily by neurobiological processes. Sleep disorders and insomnia are increasingly being diagnosed at all ages. These are risk factors for depression, mental disorders, coronary heart disease, metabolic syndrome, and/or high blood pressure. A number of factors can negatively affect sleep quality, including the use of stimulants, stress, anxiety, and the use of electronic devices before sleep. A growing body of evidence suggests that nutrition, physical activity, and sleep hygiene can significantly affect the quality of sleep. The aim of this review was to discuss the factors that can affect sleep quality, such as nutrition, stimulants, and physical activity.

The impact of sleep events on weight gain following early adenotonsillectomy compared to supportive care for pediatric OSA

OBJECTIVES

Children with obstructive sleep apnea (OSA) who undergo adenotonsillectomy (AT) often experience post-operative weight gain, although the mechanism remains unclear. Our aim is to understand how changes in sleep events impact changes in weight in children with OSA following adenotonsillectomy compared to watchful waiting with supportive care.

METHODS

We performed a secondary analysis of the Childhood adenotonsillectomy trial (CHAT) dataset in which children with OSA were randomized to undergo early adenotonsillectomy (eAT) or watchful waiting with supportive care (WWSC). The primary outcome measures included changes in body mass index (BMI) percentile, apnea-hypopnea index (AHI) and arousal index (AI) during rapid eye movement (REM) sleep. The change in BMI percentile attributable to changes in AHI and AI during REM sleep was determined using causal mediation analysis.

RESULTS

Of the 453 children with OSA randomized to eAT or WWSC, 397 children were included in the analysis. Children in the eAT arm experienced a greater increase in their weight as measured by BMI percentile, compared to children who received WWSC (WWSC 4.12 (2.70, 5.55) vs. eAT 6.62 (4.87, 8.38), Cohen's d = 0.22 (0.02, 0.42), p = 0.02). A significant proportion of the weight gain was attributable to decreases in apneic events (proportion mediated 19% (2-97%), p = 0.03) and arousals (proportion mediated 20% (5-78%), p = 0.01) during REM sleep.

CONCLUSION

A significant proportion of post-adenotonsillectomy weight gain in children with OSA is attributable to polysomnographic changes during REM sleep, potentially due to the mitigation of REM-related sleep fragmentation and subsequent reduction in metabolic expenditure.

Polysomnographic comparison of sleep in children with obesity and normal weight without suspected sleep-related breathing disorder

Short sleep and obstructive apneas/hypopneas have been shown to be associated with childhood obesity. Still, few studies have compared sleep in children with obesity, without suspected sleep disordered breathing and normal weight peers by objective sleep measures and compared results with subjective parent assessment of sleep. Children with obesity aged 7-13 years (N = 44) and a matched group of normal weight children (N = 42) completed clinical polysomnography (Embla A10 Recording System). Parents scored their children's sleep on the Children's Sleep Habits Questionnaire (CSHQ). Mann-Whitney U tests were used to compare groups. There was a higher obstructive apnea/hypopnea index (AHI) (median obesity = 1.20 vs. median normal  = 0.66; z = -1.33, U = 560.50, p = 0.002) and number of oxygen desaturation events per hour (median obesity = 0.7 vs. median normal  = 0.2; z = -3.45, U = 402.50, p = 0.001) in the children with obesity compared to children with normal weight. The children with obesity had a significantly longer sleep duration (median obesity 8:50 h = vs. median normal = 8:32 h; z = -2.05, U = 687.00, p = 0.041), longer stage N2 sleep (median obesity = 87 min vs. median normal = 52 min; z = -2.87, U = 576.50, p = 0. 004) and shorter REM sleep (median obesity = 94 min vs. median normal = 121 min; z = 5.05, U = 1477.00, p ≤ .001). No differences were observed for time in sleep stage N1 and N3, wake time after sleep onset or the total arousal index . Further, no group differences were found on the CSHQ sleep-disordered breathing sub-scale (p = 0.399). The children with obesity demonstrated significantly more mild to moderate sleep disordered breathing than children with normal weight, although this was not corroborated by parent report.

[Comparative Study of Clinical Manifestations and Sleep Structure in Children with Obstructive Sleep Apnea-hypopnea Syndrome with Different BMI]

OBJECTIVE

To compare and analyze the clinical manifestations and sleep structure of children with obstructive sleep apnea-hypopneasyndrome (OSAHS) with different body mass index (BMI).

METHODS

452 children who were diagnosed with OSAHS between December 2016 and February 2021 by the Department of Respiratory Medicine, Children's Hospital of Soochow University were included in the study. All of them did polysomnography (PSG). They were divided, according to their BMI, into the normal BMI group, the overweight group, and the obesity group. Their clinical data and PSG results were collected.

RESULTS

287 boys (63.5%) and 165 girls (36.5%) were enrolled, with their age ranging between 3 and 15, and the median age being 5.5 (4.5, 7.0). Their BMI ranged between 12.09 kg/m 2 and 38.48 kg/m 2, with the median being 16.29 kg/m 2. 275 cases (60.8%) had normal BMI, 76 cases (16.8%) were overweight, and 101 cases (22.3%) were obese. There was no significant difference in the distribution of clinical manifestations and severity of OSAHS among the three groups. The duration and proportion of rapid eye movement (REM) stage sleep in the obese group was lower than that of the overweight and the normal BMI groups ( P<0.05). The lowest oxyhemoglobin saturation (LSaO 2) of children in the overweight group was lower than that of the normal BMI group ( P=0.050). The oxygen desaturation index (ODI) of the obese group was higher than that of the normal BMI and the overweight groups ( P<0.05).

CONCLUSION

Obesity worsens the degree of hypoxia in children with OSAHS and affects their sleep structure.

Associations of frequent pain symptoms with excessive daytime sleepiness in adolescents: a longitudinal study

STUDY OBJECTIVES

Pain symptoms, sleep disturbance, and daytime sleepiness are common in adolescents. This study examined the cross-sectional and prospective associations between pain symptoms and excessive daytime sleepiness (EDS) in a large sample of adolescents.

METHODS

Participants were 7,072 adolescents (mean age = 14.6 years) in a follow-up study of behavior and health in Shandong, China. A self-administered structured questionnaire was used to assess pain symptoms (headache, stomachache, and other general pain), body weight and height, sleep, anxiety/depression, substance use, and family environment in November-December in 2015 and one year later. The Chinese adolescent daytime sleepiness scale (CADSS) was used to measure daytime sleepiness.

RESULTS

Of the sample, 19.8% and 23.2% had moderate or severe EDS at baseline and at 1-year follow-up, respectively. The prevalence and 1-year incidence rates of EDS significantly increased with the frequencies of pain symptoms. Frequent pain was significantly associated with increased risk of EDS at baseline (OR=2.01, 95% CI=1.56-2.59), incident EDS (OR=1.41, 95% CI=1.03-1.93), and persistent EDS (OR=2.17, 95% CI=1.52-3.09) while adjusting for adolescent and family covariates, including anxiety/depression, nocturnal sleep duration, insomnia symptoms, frequent snoring, body mass index, and hypnotic use. Similar associations were observed across headache, stomachache, and other pain.

CONCLUSIONS

Frequent pain is significantly and independently associated with increased risk of EDS. Our findings suggest that assessing and treating pain symptoms is important to improve healthy sleep and reduce risk of EDS in adolescents. Further research is needed to understand the underlying psychological and neurobiological mechanisms between pain and daytime sleepiness in adolescents.

Effects of macronutrient intake on sleep duration and quality: A systematic review

AIM

The aim of this systematic review was to characterise and synthesise the literature that explores the effects of macronutrient manipulation on sleep outcomes in order to provide dietary recommendations for sleep improvement.

METHODS

Intervention studies that evaluated the effects of macronutrient manipulations on sleep were identified using four databases. A study was included if it: (a) delivered a macronutrient-based dietary intervention, regardless of length; (b) included healthy human participants aged 18 and older; and (c) measured some aspect of sleep, for example, duration or quality, in some manner.

RESULTS

A total of 17 papers and 19 studies met the inclusion criteria. Included studies were organised into acute studies lasting less than 24 hours (n = 4), longer-term (≥24 hours) studies (n = 10), and energy restriction studies (n = 5). The greatest amount of support was observed for longer-term administration of higher carbohydrate diets. These interventions positively influenced rapid eye movement sleep; however, non-rapid eye movement sleep was negatively affected. The overall health outcomes of these changes are difficult to assess. Limited evidence suggests higher protein diets under conditions of energy restriction can improve sleep quality, but these effects might be restricted to individuals with overweight or obesity. Current evidence does not support the effects of acute macronutrient manipulation, defined as less than 24 hours, on sleep outcomes.

CONCLUSIONS

Manipulating carbohydrate intake for at least 24 hours appears to alter sleep outcomes among healthy individuals. Interventions were highly varied and methodological shortcomings were identified. More work is required to fully understand how macronutrient intake affects sleep outcomes.

The Relationship between Sleep, Obesity, and Metabolic Health in Adolescents - a Review

In this literature review, we discuss the importance of adequate sleep and the various effects of suboptimal sleep on weight maintenance and metabolic health specifically for adolescents. Two major contributors to adolescents experiencing decreased sleep duration and quality, and thus increasing the risk for developing metabolic syndrome in adolescence as well as later in adulthood, are increased electronic screen time particularly at night and early school start times. The less time adolescents spend sleeping, the less quality sleep they obtain, and the greater the disruption of endocrine hormone function. As another consequence, adolescents are more prone to making poor food choices, from choosing relatively nutrient-poor foods to consuming excess calories without necessarily increasing their energy expenditure. These choices put adolescents at greater risk for becoming obese throughout their lifespan.

Severe paediatric obesity and sleep: A mutual interactive relationship!

Childhood severe obesity is a serious, urgent and complex global health problem with long-term co-morbidities. Obstructive sleep-disordered breathing is more common in obese children and adolescents. Increased body mass index is associated with an increase in apnea-hypopnea index. Obstructive sleep apnea leads to a decrease in rapid eye movement sleep, and obese children have been noted to have a decrease in rapid eye movement sleep, leading to weight gain. Short sleep duration and poor sleep quality are associated with childhood obesity and cardiometabolic risks. Public health strategies for obesity prevention should focus more on sleep. Targeting childhood obesity is important in the prevention and management of obstructive sleep-disordered breathing.

Chronic REM sleep restriction in young rats increases energy expenditure with no change in food intake

NEW FINDINGS

What is the central question of this study? What are the effects of different periods of REM sleep restriction (7, 14 and 21 days) on metabolic parameters in young rats? What is the main finding and its importance? Animals submitted to each period of REM sleep deprivation showed a negative energy balance, with reduced body weight gain, body energy gain and gross food efficiency, less body fat content, and increased energy expenditure. There was no increase in food intake after any of the REM sleep restriction periods. In young rats, negative energy balance is not compensated by increased dietary intake as observed in adult rats.

ABSTRACT

Reduced sleep is associated with metabolic alterations, not only in adults, but also in children and adolescents. Several studies have shown that sleep restricted (SR) adult rats exhibit metabolic changes, followed by increased food intake, but few have evaluated these functions in young animals. The aim of the present study was to establish the metabolic parameters of young rats subjected to different periods of REM sleep restriction and to propose a correction factor for the correct measurement of food intake. Young male Wistar rats were distributed in control and SR groups for 7, 14 or 21 days. Sleep restriction was performed by the single platform method for 18 h. Regardless of the length of sleep restriction, all SR rats had a negative energy balance, evidenced by reduction in body weight gain, body energy gain and gross food efficiency, accompanied by increased energy expenditure. In addition, sleep restriction reduced body fat content throughout the entire period. Discounting food spillage, there was no increase in food intake by SR rats. In conclusion, the present study revealed metabolic changes in SR young rats after different lengths of REM sleep restriction and that weight loss and increased energy expenditure were not compensated by increased dietary intake as occurs in adult rats, indicating that young rats use other mechanisms to cope with the negative energy balance caused by sleep restriction. In addition, we propose a correction factor for food intake, to prevent overestimation of this parameter, due to food spillage in the water containers.

Randomized Double-Blind Controlled Trial on the Effect of Proteins with Different Tryptophan/Large Neutral Amino Acid Ratios on Sleep in Adolescents: The PROTMORPHEUS Study

Disturbed sleep is common in adolescents. Ingested nutrients help regulate the internal clock and influence sleep quality. The purpose of this clinical trial is to assess the effect of protein tryptophan (Trp)/large neutral amino acids (LNAAs) ratio on sleep and circadian rhythm. Ingested Trp is involved in the regulation of the sleep/wake cycle and improvement of sleep quality. Since Trp transport through the blood-brain barrier is competing with LNAAs, protein with higher Trp/LNAAs were expected to increase sleep efficiency. This randomized double-blind controlled trial will enroll two samples of male adolescents predisposed to sleep disturbances: elite rugby players (n = 24) and youths with obesity (n = 24). They will take part randomly in three sessions each held over a week. They will undergo a washout period, when dietary intake will be calibrated (three days), followed by an intervention period (three days), when their diet will be supplemented with three proteins with different Trp/LNAAs ratios. Physical, cognitive, dietary intake, appetite, and sleepiness evaluations will be made on the last day of each session. The primary outcome is sleep efficiency measured through in-home electroencephalogram recordings. Secondary outcomes include sleep staging, circadian phase, and sleep-, food intake-, metabolism-, and inflammation-related biochemical markers. A fuller understanding of the effect of protein Trp/LNAAs ratio on sleep could help in developing nutritional strategies addressing sleep disturbances.

Sleep and obesity among children: A systematic review of multiple sleep dimensions

The objectives were to systematically investigate the multiple dimensions of sleep and their association with overweight or obesity among primary school-aged children. CINHAL, PsycINFO, SPORTDiscus, Medline, Cochrane, Embase, and PubMed databases were searched for papers reporting on an association between children's sleep and weight status. Studies on clinical populations, published in languages other than English, without objectively measured weight status, or where weight status was reported outside the outlined age bracket (5-13 years) were excluded. A total of 34  248 citations were extracted from our systematic search protocol, of which 112 were included for detailed review. Compared with sleep duration, of which 86/103 articles found a significant inverse association between sleep duration and measured weight status, few studies examined other dimensions of sleep, such as quality, efficiency and bed/wake times, and relationship with weight status. Where studies existed, variation in defining and measurement of these dimensions restricted comparison and potentially influenced discrepancies across results. Overall, the findings of this review warrant the need for further research of the outlined dimensions of sleep. Future research would benefit from clarity on definitions across the different dimensions, along with the use of valid and reliable tools.

Differences in sleep architecture according to body mass index in children with type 1 diabetes

Slow wave sleep (SWS), or deep sleep, is thought to be the most restorative stage of sleep and may be of a particular interest in the pathophysiology of obesity. The aim of this study was to investigate differences in sleep architecture based on body mass index (BMI) among a pediatric population with type 1 diabetes mellitus (T1DM). We hypothesized that children with T1DM who are obese would have less SWS than those who are not obese. Of 105 children with T1DM (mean age 13.54 years, 49.5% females) in this study, 19% were obese, 22% were overweight, and 59% had a normal BMI (81% non-obese). The overall SWS% among the participants was 13.2%. In contrast to our hypothesis, there was no significant difference in SWS% between obese and non-obese participants. However, the percent of time spent in rapid eye movement (REM) sleep among obese participants was significantly lower than those who were not obese (P = .022), which remained after adjusting the result for multiple covariates. While we found no significant association between the SWS time and BMI, obese adolescents with T1DM spent less time in REM sleep than those who were not obese. This study adds to the growing body of evidence supporting the importance of addressing sleep in clinical care of youth with T1DM.

Night-time cardiac autonomic modulation as a function of sleep-wake stages is modified in otherwise healthy overweight adolescents

OBJECTIVE

Even though sympathetic dominance during the daytime period is well known, currently, scarce data exist on autonomic nervous system (ANS) regulation during sleep in pediatric obesity. We aimed to evaluate sleep cardiac ANS regulation in normal-weight (NW) and overweight and obese (OW) adolescents.

PATIENTS/METHODS

In this study, 60 healthy adolescents (15.7 ± 0.7 years) belonging to a birth cohort since infancy were classified based on body mass index percentiles criteria as: OW (N = 27) or NW (N = 33). Sleep was evaluated by polysomnography (PSG) during two consecutive in-lab overnight sessions. Non-rapid eye movement (non-REM) sleep stages (stages 1, 2, and slow-wave sleep [SWS]), rapid eye movement (REM) sleep, and wakefulness (Wake) were scored. R-waves were detected automatically in the electrocardiographic (ECG) signal. An all-night heart rate variability analysis was conducted in the ECG signal, with several time- and frequency-domain measures calculated for each sleep-wake stage. Sleep time was divided into thirds (T1, T2, T3). The analysis was performed using a mixed-effects linear regression model.

RESULTS

Sleep organization was comparable except for reduced REM sleep percentage in the OW group (p < 0.04). Shorter R-R intervals were found for all sleep stages in the OW group; time-domain measured standard deviation of all R-R intervals (RRSD) was lower during stage 2, SWS and REM sleep (all p < 0.05). The square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) was also lower only during wake after sleep onset (WASO) in T1 and T3 (p < 0.05). The OW group had increased very low- and low-frequency (LF) power during WASO (in T1 and T2), and LF power during stage 2 and REM sleep (in T2). During WASO in the OW group, high-frequency (HF) power was lower (in T1 and T2), and LF/HF ratio was higher (in T2, p < 0.007).

CONCLUSIONS

Several sleep-stage-dependent changes in cardiac autonomic regulation characterized the OW group. As sleep-related ANS balance was disturbed in the absence of concomitant metabolic alterations in this sample of otherwise healthy OW adolescents, their relevance for pediatric obesity should be further explored throughout development.

Sleep disorders in polycystic ovary syndrome: influence of obesity and hyperandrogenism

OBJECTIVE

This study aims to evaluate the sleep of subjects with polycystic ovary syndrome (PCOS), with and without hyperandrogenism, in comparison with a healthy control group and examine the effects of hyperandrogenism and obesity on sleep parameters.

METHODS

A total of 44 volunteers were recruited to participate in the study. Clinical, biochemical and polysomnographic parameters were used to diagnose PCOS and hyperandrogenism. The evaluation of sleep quality was made using validated questionnaires and polysomnography test. The frequency of obstructive sleep apnea was also compared between the groups.

RESULTS

The study revealed that women with PCOS presented poorer subjective sleep quality, increased incidence of snoring and a higher risk of obstructive sleep apnea, based on the Berlin questionnaire. Also, after adjusting for body mass index, PCOS subjects had rapid eye movement (REM) time lower than those in the control group. PCOS women versus those without hyperandrogenism did not differ on any sleep measurement. Women with obstructive sleep apnea were only diagnosed in the PCOS group.

CONCLUSIONS

Our results indicate that PCOS impairs subjective sleep quality, as well as objective sleep quality, due to a reduction in REM sleep stage time in women diagnosed with the syndrome. Obesity affected sleep-related parameters but hyperandrogenism had no effect. Only the PCOS group had obstructive sleep apnea diagnosis.

Association between REM sleep and obstructive sleep apnea in obese and overweight adolescents

PURPOSE

Overweight and obese children have demonstrated reduced rapid eye movement (REM) sleep, affecting energy balance regulation and predisposition to weight gain. Obstructive sleep apnea (OSA) is a known cause of decreased REM sleep. The purpose of this study is to examine the association between the percentage of REM sleep, BMI z-score, and OSA severity in overweight and obese adolescents.

METHODS

We performed a cross-sectional study of 92 (43% female) overweight and obese adolescents (13-17 years old) who underwent overnight polysomnography (PSG) at Children's Hospital Los Angeles between 2010 and 2017.

RESULTS

The average Body Mass Index (BMI) z-score was 2.27 ± 0.47, with 71% having BMI z-score ≥ 2. REM% during PSG was 15.6 ± 6.8, and obstructive apnea-hypopnea index was 17.1 ± 24.3. The distribution across categories of OSA severity was 27% none (≤ 1.5 events/h), 24% mild (> 1.5-5 events/h), 8% moderate (> 5-10 events/h), and 41% severe (> 10 events/h). REM% was not associated with BMI z-score, either on univariate or multivariate regression with adjustment for age, gender, and apnea-hypopnea index (AHI). When subdivided into OSA categories, a 1-unit increase in BMI z-score was associated with a 5.96 (p = 0.03) increase in REM% in mild OSA and an 8.86 (p = 0.02) decrease in REM% in severe OSA. There was no association between BMI z-score and REM% in none and moderate OSA.

CONCLUSION

Among overweight and obese adolescents, BMI z-score was associated with decreased REM% in severe OSA and unexpectedly increased REM% in mild OSA, but there was no association in none or moderate OSA.

The Importance of Sleep Hygiene in Polycystic Ovary Syndrome from the View of Iranian Traditional Medicine and Modern Medicine

Polycystic ovary syndrome (PCOS) is known as the most common hormonal disorder in women at reproductive age. Recent studies have revealed a high prevalence of sleep disorders in PCOS, suggesting that it is an amendable factor for these patients; however, the sleep was not considered in their treatment plan. According to the Iranian traditional medicine (ITM), sleep is an important item in the lifestyle modification of all diseases. The aim of this study is to determine the importance of sleep hygiene in PCOS from the view of ITM and Modern Medicine. In this study, some keywords about “sleep and PCOS” were searched in medical databases and some ITM books. Lifestyle modification is one of the first steps in treatment of patients with PCOS in which the emphasis will be mainly on exercise and diet. Despite proof of the high prevalence of sleep disorders in these patients, modification of sleep is not considered in their lifestyle. ITM as a holistic medicine emphasizes on lifestyle modification under the title of “Settah-e-Zaruria” (In Persian), the six essential schemes for the prevention and treatment of all diseases. Management of sleep is one of these schemes. There are many advices about sleep hygiene in both ITM and modern medicine. It seems that lifestyle modification should be expanded in PCOS patients to include more options, and sleep hygiene should be considered in their lifestyle alongside food and exercise.

Obstructive Sleep Apnea and Sleep Architecture in Adolescents With Severe Obesity: Effects of a 9-Month Lifestyle Modification Program Based on Regular Exercise and a Balanced Diet

STUDY OBJECTIVES

Physical exercise and lifestyle modification are recognized as adjunct therapy for obstructive sleep apnea (OSA) in overweight adults. The objectives of this study were to investigate the effects of long-term physical exercise combined with a balanced diet on sleep architecture, sleep duration, and OSA in adolescents with severe obesity.

METHODS

This interventional study was conducted in a nursing institution. Participants were aged 14.6 ± 1.2 years with obesity (body mass index (BMI) = 40.2 ± 6.5 kg/m2). At admission and at 9 months, participants underwent ambulatory polysomnography and incremental maximal exercise testing to determine cardiorespiratory fitness.

RESULTS

Twenty-four subjects completed the study. Analyses were performed on the whole population and on a subgroup of subjects with OSA (OSA-subgroup). OSA, defined as obstructive apnea-hypopnea index (OAHI) ≥ 2 events/h, was diagnosed in 58.3% of the population. OAHI was only associated with fat mass in males (r = .75, P < .05). At 9 months postintervention, weight loss (-11.1 kg, P < .0001) and improved cardiorespiratory fitness (VO2peak: +4.9 mL/min/kg, P < .001) were found in the whole population. Sleep duration was increased (+34 minutes, P < .05) and sleep architecture was changed with an increase of rapid eye movement sleep (+2.5%, P < .05) and a decrease of stage N3 sleep (-3.1%, P < .001). Similar results were found in the OSA subgroup. However, OAHI remained unchanged (P = .18).

CONCLUSIONS

A combination of supervised aerobic exercise and a balanced diet led to weight loss, improved aerobic capacity, and modified sleep architecture without changes in OSA.

COMMENTARY

A commentary on this article appears in this issue on page 907.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Title: Exercise and Venous Compression on Upper Airway Resistance in Obese Teenagers With OSA (OBESOMAC), URL: https://clinicaltrials.gov/ct2/show/NCT02588469, Identifier: NCT02588469.

Sleeping oxygen saturation, rapid eye movement sleep, and the adaptation of postprandial metabolic function in insulin sensitive and resistant individuals without diabetes

AIMS

Sleeping oxygen saturation (SaO₂) and sleep stage duration have been linked with prediabetic alterations but the pathogenic pathways are not well understood. This study of insulin sensitive and resistant adults examined the effect on postprandial metabolic regulation of repeated mixed-meal challenges of different carbohydrate loading. The aim was to examine whether the relationship between lower sleeping oxygen saturation (SaO₂) and poorer fasting and postprandial metabolic function may be linked with reduced slow wave sleep (SWS) and rapid eye movement (REM) duration, independent of age, sex and total adiposity.

METHODS

The 24 men and women, aged 25-54 years, had no diabetes or other diagnosed conditions, were evaluated with polysomnography to derive indices of SaO₂ and sleep architecture. In addition, an OGTT and two 14-h serial mixed-meal tests were administered over 3 successive in-patient days. The carbohydrate content of the mixed-meals was manipulated to compare a standard-load day with a double-load day (300 vs. 600 kcal/meal). Quantitative modeling was applied to derive β-cell glucose sensitivity (β-GS), early insulin secretion rate sensitivity (ESRS), and total postprandial insulinemia (AUC_INS).

RESULTS

Analyses showed that, for the 14-h tests, the SaO₂ relationship with metabolic outcomes was associated significantly with percent time spent in REM but not SWS, independent of age, sex and total adiposity. Specifically, indirect pathways indicated that lower SaO₂ was related to shorter REM duration, and shorter REM was respectively associated with higher β-GS, ESRS, and AUC_INS for the 300- and 600-load days (300 kcal/meal: β = -8.68, p < .03, β = -8.54, p < .002, and β = -10.06, p < .008; 600 kcal/meal: β = -11.45, p < .003, β = -11.44, p < .001, and β = -11.00, p < .03).

CONCLUSION

Sleeping oxygen desaturation and diminished REM duration are associated with a metabolic pattern that reflects a compensatory adaptation of postprandial insulin metabolism accompanying preclinical diabetic risk.

Poor Sleep and Obesity: Concurrent Epidemics in Adolescent Youth

Poor sleep and obesity are both extraordinarily common in the US adolescent population and often occur simultaneously. This review explores the links between obesity and sleep, outlining what is known about the relationships between sleep characteristics, obesity, and cardiometabolic risk factors in youth. Sleep duration is less than optimal in teens, and decreases as age increases. This is detrimental to overall well-being and is associated with obesity in children, adolescents, and young adults. Accordingly, inadequate sleep duration is associated with poor diet quality, decreased insulin sensitivity, hyperglycemia, and prevalent cardiometabolic risk factors. Evidence suggests that poor sleep quality and altered circadian timing characterized by a preferred later sleep onset, known as "adolescent chronotype," contributes to shortened sleep duration. Obstructive sleep apnea (OSA) occurs more frequently among youth with obesity, and is associated with autonomic nervous system activity promoting higher blood pressure, increased markers of cardiovascular disease risk, and insulin resistance. While there is a clear association between OSA and type 2 diabetes in adults, whether or not this association is prevalent in youth is unclear at this time. Interventions to improve both sleep duration and quality, and obesity in adolescents are scarce and more evidence is needed to determine if such interventions can improve obesity-related health outcomes.

Chemogenetic inhibition of the medial prefrontal cortex reverses the effects of REM sleep loss on sucrose consumption

Rapid eye movement (REM) sleep loss is associated with increased consumption of weight-promoting foods. The prefrontal cortex (PFC) is thought to mediate reward anticipation. However, the precise role of the PFC in mediating reward responses to highly palatable foods (HPF) after REM sleep deprivation is unclear. We selectively reduced REM sleep in mice over a 25–48 hr period and chemogenetically inhibited the medial PFC (mPFC) by using an altered glutamate-gated and ivermectin-gated chloride channel that facilitated neuronal inhibition through hyperpolarizing infected neurons. HPF consumption was measured while the mPFC was inactivated and REM sleep loss was induced. We found that REM sleep loss increased HPF consumption compared to control animals. However, mPFC inactivation reversed the effect of REM sleep loss on sucrose consumption without affecting fat consumption. Our findings provide, for the first time, a causal link between REM sleep, mPFC function and HPF consumption.

DOI:http://dx.doi.org/10.7554/eLife.20269.001

Sleep quality and duration is related with diet and obesity in young adolescent living in Sicily, Southern Italy

The aim of this study was to evaluate the association between sleeping habits, Mediterranean diet pattern, and weight status in an adolescent population. The sample consisted of 1586 individuals aged 11–14 years attending 15 secondary schools of Sicily, Southern Italy. School were randomly selected and the data collected during two school years. Anthropometric data was collected and body composition was assessed by bioelectrical impedance analysis. Demographic information, sleep duration, pediatric daytime sleepiness questionnaire (PDSS), physical activity and dietary habits (including adherence to the Mediterranean Diet using the KIDMED score) were further collected. The mean age was 12±0.7 and about 24% were overweight and obese. An inverse correlation between total sleep time and body mass index (β=−0.829, P=0.021), fat mass (β=−0.526, P=0.025), and waist circumference (β=−0.426, P=0.045) was found. Similar results were found for weekdays sleep time, while an inverse relationship was found with PDSS score. Adherence to Mediterranean Diet was higher in under/normal weight adolescent with a significant linear association between the KIDMED score and the PDSS, weekdays sleep time and total sleep time. Sleep duration was also associated positively with fruits and vegetable intake and negatively with sweet and snack consumption and eating outside habits. Short sleep duration and poor sleep were associated with an increase in BMI and fat mass as well as to unhealthy eating behaviors. These findings suggest that sleep patterns could be a potential target for obesity prevention programs in young adolescence.

Obstructive Sleep Apnea

Introduction

The severity of obstructive sleep apnea in children determines perioperative management and is an indication for postoperative polysomnography. The relationship between increasing weight and sleep apnea severity in children remains unclear.

Objectives

To compare demographic, clinical, and polysomnography parameters in normal-weight, overweight, obese, and morbidly obese children, as well as identify demographic factors that predict sleep apnea severity.

Study Design

Case series with chart review.

Setting

Academic children’s hospital.

Methods

A retrospective chart review of 290 children aged 2 to 18 years who underwent polysomnography at an academic children’s hospital was performed. Demographics, clinical findings, and polysomnographic parameters were recorded. Children were categorized as normal weight, overweight, obese, or morbidly obese. Differences were assessed using linear and logistical regression models. Significance was set at P < .05.

Results

Morbidly obese were older than normal-weight children (mean, 8.0 ± 0.5 years vs 5.8 ± 0.3 years; P < .001) and less likely to have a normal polysomnogram (16% vs 48%; P = .02). There were no differences in sex, ethnicity, birth status (term or preterm), or tonsil size between normal-weight, overweight, obese, and morbidly obese children. Sleep efficiency and percentage of time in rapid eye movement were decreased in morbidly obese compared with other children ( P < .05). The apnea-hypopnea index was positively correlated with increasing body mass index z score only as a function of increasing age ( P < .001).

Conclusion

Obstructive sleep apnea severity is correlated with a combination of increasing age and weight but not with either variable independently. This study suggests that obese and morbidly obese older children are most likely to have severe obstructive sleep apnea.

Percentage of REM sleep is associated with overnight change in leptin

Sleep contributes importantly to energy homeostasis, and may impact hormones regulating appetite, such as leptin, an adipocyte-derived hormone. There is increasing evidence that sleep duration, and reduced rapid eye movement sleep, are linked to obesity. Leptin has central neural effects beyond modulation of appetite alone. As sleep is not a unifrom process, interactions between leptin and sleep stages including rapid eye movement sleep may play a role in the relationship between sleep and obesity. This study examined the relationship between serum leptin and rapid eye movement sleep in a sample of healthy adults. Participants were 58 healthy adults who underwent polysomnography. Leptin was measured before and after sleep. It was hypothesized that a lower percentage of rapid eye movement sleep would be related to lower leptin levels during sleep. The relationship between percentage of rapid eye movement sleep and leptin was analysed using hierarchical linear regression. An increased percentage of rapid eye movement sleep was related to a greater reduction in leptin during sleep even when controlling for age, gender, percent body fat and total sleep time. A greater percentage of rapid eye movement sleep was accompanied by more marked reductions in leptin. Studies examining the effects of selective rapid eye movement sleep deprivation on leptin levels, and hence on energy homeostasis in humans, are needed.

Restriction of rapid eye movement sleep during adolescence increases energy gain and metabolic efficiency in young adult rats

NEW FINDINGS

What is the central question of this study? Sleep curtailment in infancy and adolescence may lead to long-term risk for obesity, but the mechanisms involved have not yet been determined. This study examined the immediate and long-term metabolic effects produced by sleep restriction in young rats. What is the main finding and its importance? Prolonged sleep restriction reduced weight gain (body fat stores) in young animals. After prolonged recovery, sleep-restricted rats tended to save more energy and to store more fat, possibly owing to increased gross food efficiency. This could be the first step to understand this association. Sleep curtailment is associated with obesity and metabolic changes in adults and children. The aim of the present study was to evaluate the immediate and long-term metabolic alterations produced by sleep restriction in pubertal male rats. Male Wistar rats (28 days old) were allocated to a control (CTL) group or a sleep-restricted (SR) group. This was accomplished by the single platform technique for 18 h per day for 21 days. These groups were subdivided into the following four time points for assessment: sleep restriction and 1, 2 and 4 months of recovery. Body weight and food intake were monitored throughout the experiment. At the end of each time period, blood was collected for metabolic profiling, and the carcasses were processed for measurement of body composition and energy balance. During the period of sleep restriction, SR animals consumed less food in the home cages. This group also displayed lower body weight, body fat, triglycerides and glucose levels than CTL rats. At the end of the first month of recovery, despite eating as much as CTL rats, SR animals showed greater energy and body weight gain, increased gross food efficiency and decreased energy expenditure. At the end of the second and fourth months of recovery, the groups were no longer different, except for energy gain and gross food efficiency, which remained higher in SR animals. In conclusion, sleep restriction affected weight gain of young animals, owing to reduction of fat stores. Two months were sufficient to recover this deficit and to reveal that SR rats tended to save more energy and to store more fat.

Sleep disturbances, body fat distribution, food intake and/or energy expenditure: pathophysiological aspects

Data from cross-sectional and longitudinal studies have illustrated a relationship between short sleep duration (SSD) and weight gain. Individuals with SSD are heavier and gain more weight over time than normal-duration sleepers. This sleep-obesity relationship may have consequences for obesity treatments, as it appears that short sleepers have reduced ability to lose weight. Laboratory-based clinical studies found that experimental sleep restriction affects energy expenditure and intake, possibly providing a mechanistic explanation for the weight gain observed in chronic short sleepers. Specifically, compared to normal sleep duration, sleep restriction increases food intake beyond the energetic costs of increased time spent awake. Reasons for this increased energy intake after sleep restriction are unclear but may include disrupted appetite-regulating hormones, altered brain mechanisms involved in the hedonic aspects of appetite, and/or changes in sleep quality and architecture. Obstructive sleep apnea (OSA) is a disorder at the intersection of sleep and obesity, and the characteristics of the disorder illustrate many of the effects of sleep disturbances on body weight and vice versa. Specifically, while obesity is among the main risk factors for OSA, the disorder itself and its associated disturbances in sleep quality and architecture seem to alter energy balance parameters and may induce further weight gain. Several intervention trials have shown that weight loss is associated with reduced OSA severity. Thus, weight loss may improve sleep, and these improvements may promote further weight loss. Future studies should establish whether increasing sleep duration/improving sleep quality can induce weight loss.

Human REM sleep: influence on feeding behaviour, with clinical implications

Rapid eye movement (REM) sleep shares many underlying mechanisms with wakefulness, to a much greater extent than does non-REM, especially those relating to feeding behaviours, appetite, curiosity, exploratory (locomotor) activities, as well as aspects of emotions, particularly 'fear extinction'. REM is most evident in infancy, thereafter declining in what seems to be a dispensable manner that largely reciprocates increasing wakefulness. However, human adults retain more REM than do other mammals, where for us it is most abundant during our usual final REM period (fREMP) of the night, nearing wakefulness. The case is made that our REM is unusual, and that (i) fREMP retains this 'dispensability', acting as a proxy for wakefulness, able to be forfeited (without REM rebound) and substituted by physical activity (locomotion) when pressures of wakefulness increase; (ii) REM's atonia (inhibited motor output) may be a proxy for this locomotion; (iii) our nocturnal sleep typically develops into a physiological fast, especially during fREMP, which is also an appetite suppressant; (iv) REM may have 'anti-obesity' properties, and that the loss of fREMP may well enhance appetite and contribute to weight gain ('overeating') in habitually short sleepers; (v) as we also select foods for their hedonic (emotional) values, REM may be integral to developing food preferences and dislikes; and (vii) REM seems to have wider influences in regulating energy balance in terms of exercise 'substitution' and energy (body heat) retention. Avenues for further research are proposed, linking REM with feeding behaviours, including eating disorders, and effects of REM-suppressant medications.

The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

Modern lifestyle has profoundly modified human sleep habits. Sleep duration has shortened over recent decades from 8 to 6.5 hours resulting in chronic sleep deprivation. Additionally, irregular sleep, shift work and travelling across time zones lead to disruption of circadian rhythms and asynchrony between the master hypothalamic clock and pacemakers in peripheral tissues. Furthermore, obstructive sleep apnea syndrome (OSA), which affects 4 - 15% of the population, is not only characterized by impaired sleep architecture but also by repetitive hemoglobin desaturations during sleep. Epidemiological studies have identified impaired sleep as an independent risk factor for all cause of-, as well as for cardiovascular, mortality/morbidity. More recently, sleep abnormalities were causally linked to impairments in glucose homeostasis, metabolic syndrome and Type 2 Diabetes Mellitus (T2DM). This review summarized current knowledge on the metabolic alterations associated with the most prevalent sleep disturbances, i.e. short sleep duration, shift work and OSA. We have focused on various endocrine and molecular mechanisms underlying the associations between inadequate sleep quality, quantity and timing with impaired glucose tolerance, insulin resistance and pancreatic β-cell dysfunction. Of these mechanisms, the role of the hypothalamic-pituitary-adrenal axis, circadian pacemakers in peripheral tissues, adipose tissue metabolism, sympathetic nervous system activation, oxidative stress and whole-body inflammation are discussed. Additionally, the impact of intermittent hypoxia and sleep fragmentation (key components of OSA) on intracellular signaling and metabolism in muscle, liver, fat and pancreas are also examined. In summary, this review provides endocrine and molecular explanations for the associations between common sleep disturbances and the pathogenesis of T2DM.

The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

Modern lifestyle has profoundly modified human sleep habits. Sleep duration has shortened over recent decades from 8 to 6.5 hours resulting in chronic sleep deprivation. Additionally, irregular sleep, shift work and travelling across time zones lead to disruption of circadian rhythms and asynchrony between the master hypothalamic clock and pacemakers in peripheral tissues. Furthermore, obstructive sleep apnea syndrome (OSA), which affects 4 - 15% of the population, is not only characterized by impaired sleep architecture but also by repetitive hemoglobin desaturations during sleep. Epidemiological studies have identified impaired sleep as an independent risk factor for all cause of-, as well as for cardiovascular, mortality/morbidity. More recently, sleep abnormalities were causally linked to impairments in glucose homeostasis, metabolic syndrome and Type 2 Diabetes Mellitus (T2DM). This review summarized current knowledge on the metabolic alterations associated with the most prevalent sleep disturbances, i.e. short sleep duration, shift work and OSA. We have focused on various endocrine and molecular mechanisms underlying the associations between inadequate sleep quality, quantity and timing with impaired glucose tolerance, insulin resistance and pancreatic β-cell dysfunction. Of these mechanisms, the role of the hypothalamic-pituitary-adrenal axis, circadian pacemakers in peripheral tissues, adipose tissue metabolism, sympathetic nervous system activation, oxidative stress and whole-body inflammation are discussed. Additionally, the impact of intermittent hypoxia and sleep fragmentation (key components of OSA) on intracellular signaling and metabolism in muscle, liver, fat and pancreas are also examined. In summary, this review provides endocrine and molecular explanations for the associations between common sleep disturbances and the pathogenesis of T2DM.

Night time sleep macrostructure is altered in otherwise healthy 10-year-old overweight children

OBJECTIVE

Epidemiological evidence shows an inverse relationship between sleep duration and overweight/obesity risk. However, there are few polysomnographic studies that relate the organization of sleep stages to pediatric overweight (OW). We compared sleep organization in otherwise healthy OW and normal-weight (NW) 10-year-old children.

SUBJECTS

Polysomnographic assessments were performed in 37 NW and 59 OW children drawn from a longitudinal study beginning in infancy. Weight and height were used to evaluate body mass index (BMI) according to international criteria. Non-rapid eye movement (NREM) sleep (stages N1, N2 and N3), rapid eye movement (REM) sleep (stage R) and wakefulness (stage W) were visually scored. Sleep parameters were compared in NW and OW groups for the whole sleep period time (SPT) and for each successive third of it using independent Student's t-tests or nonparametric tests. The relationship between BMI and sleep variables was evaluated by correlation analyses controlling for relevant covariates.

RESULTS

The groups were similar in timing of sleep onset and offset, and sleep period time. BMI was inversely related to total sleep time (TST) and sleep efficiency. OW children showed reduced TST, sleep efficiency and stage R amount, but higher stage W amount. In analysis by thirds of the SPT, the duration of stage N3 episodes was shorter in the first third and longer in the second third in OW children as compared with NW children.

CONCLUSIONS

Our results show reduced sleep amount and quality in otherwise healthy OW children. The lower stage R amount and changes involving stage N3 throughout the night suggest that OW in childhood is associated with modifications not only in sleep duration, but also in the ongoing night time patterns of NREM sleep and REM sleep stages.

Academic performance in relation to adherence to the Mediterranean diet and energy balance behaviors in Greek primary schoolchildren

OBJECTIVE

To explore possible links between adherence to the Mediterranean Diet (MeD), excess body weight, energy balance behaviors, and academic performance in Greek primary schoolchildren.

DESIGN

Cross-sectional study.

SETTING

Primary schools in Athens, Greece.

PARTICIPANTS

A total of 528 students (256 boys and 272 girls), 10-12 years of age, were recruited from 21 primary schools in the area of Athens, Greece.

MAIN OUTCOME MEASURES

Students completed a specifically designed energy balance behaviors questionnaire together with the KIDMED index, which evaluates the degree of adherence to the MeD. The teacher assessed academic performance through a specifically designed, 5-scale questionnaire. Standard anthropometric measurements were also taken.

ANALYSIS

Block stepwise regression analysis was conducted.

RESULTS

Adherence to the MeD (β = .140; P = .001), obesity (β = -.095; P = .001), physical activity levels (β = .206; P = .001), hours of sleep (β = .100; P = .003), television viewing (β = -.068; P = .05), and global self-esteem levels (β = .122; P = .001) are significant factors in predicting academic performance in primary schoolchildren.

CONCLUSIONS AND IMPLICATIONS

Poor adherence to the MeD, obesity, and low physical activity levels seem to negatively affect academic performance in children. Understanding these interrelationships could facilitate the formation of policies focused on improving children's academic achievement.

Sleep cyclic alternating pattern in otherwise healthy overweight school-age children

STUDY OBJECTIVES

To compare sleep microstructure (cyclic alternating pattern, CAP) characteristics in otherwise healthy overweight (OW) and normal weight (NW) children.

DESIGN

Polysomnographic cross-sectional study.

SETTING

Sleep laboratory.

PARTICIPANTS

Fifty-eight (26 NW and 32 OW) 10-year-old children.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Participants were part of a longitudinal study beginning in infancy and free of sleep disorders. Groups were based on body-mass index (BMI) z-score. From polysomnographic overnight recordings, sleep-waking states were scored according to international criteria. CAP analysis was performed visually during NREM sleep. Conventional sleep parameters were similar between groups. BMI was positively related to CAP rate and CAP sequences but inversely related to CAP B phase duration. Differences between groups were confined to slow-wave sleep (SWS), with OW children showing higher CAP rate, CAP cycles, and CAP A1 number and index and shorter CAP cycles and B phase duration. They also showed more CAP class intervals shorter than 30 s, and a suggestive trend for fewer intervals longer than 30 s.

CONCLUSIONS

Cyclic alternating pattern characteristics in children related to nutritional status and were altered in overweight subjects during slow-wave sleep. We suggest that the more frequent oscillatory pattern of electroencephalographic slow activity in overweight subjects might reflect less stable slow-wave sleep episodes.

Predictors of obstructive sleep apnea severity in adenotonsillectomy candidates

STUDY OBJECTIVES

There is uncertainty over which characteristics increase obstructive sleep apnea syndrome (OSAS) severity in children. In candidates for adenotonsillectomy (AT), we evaluated the relationship of OSAS severity and age, sex, race, body mass index (BMI), environmental tobacco smoke (ETS), prematurity, socioeconomic variables, and comorbidities.

DESIGN

Cross-sectional screening and baseline data were analyzed from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study evaluating AT versus medical management. Regression analysis assessed the relationship between the apnea hypopnea index (AHI) and risk factors obtained by direct measurement or questionnaire.

SETTING

Clinical referral setting.

PARTICIPANTS

Children, ages 5 to 9.9 y with OSAS.

MEASUREMENTS AND RESULTS

Of the 1,244 children undergoing screening polysomnography, 464 (37%) were eligible (2 ≤ AHI < 30 or 1 ≤ obstructive apnea index [OAI] < 20 and without severe oxygen desaturation) and randomized; 129 (10%) were eligible but were not randomized; 608 (49%) had AHI/OAI levels below entry criteria; and 43 (3%) had levels of OSAS that exceeded entry criteria. Among the randomized children, univariate analyses showed significant associations of AHI with race, BMI z score, environmental tobacco smoke (ETS), family income, and referral source, but not with other variables. After adjusting for potential confounders, African American race (P = 0.003) and ETS (P = 0.026) were each associated with an approximately 20% increase in AHI. After adjusting for these factors, obesity and other factors were not significant.

CONCLUSIONS

Apnea hypopnea index level was significantly associated with race and environmental tobacco smoke, highlighting the potential effect of environmental factors, and possibly genetic factors, on pediatric obstructive sleep apnea syndrome severity. Efforts to reduce environmental tobacco smoke exposure may help reduce obstructive sleep apnea syndrome severity.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov (#NCT00560859).