Short sleep duration and obesity among children: A systematic review and meta-analysis of prospective studies

Maternal Sleep Quality is Associated with Personal and Parenting Weight-Related Behaviors

Mothers of young children tend to report poor-quality sleep, yet little is known about links between maternal sleep quality and weight-related behaviors and parenting practices. Thus, mothers of preschoolers completed an online cross-sectional survey assessing their sleep, physical activity, dietary behaviors, eating styles, child feeding practices, family meal behaviors, and health parameters. Comparisons by sleep quality using the Pittsburgh Sleep Quality Index item (i.e., very bad/bad, n = 87; fair, n = 255; and good/very good, n = 193) revealed mothers with poor-quality sleep had weight-related behaviors associated with higher Body Mass Index (BMI) (lower physical activity, fewer fruits/vegetables, more emotional and disinhibited eating). Poor-quality sleepers also engaged in parenting practices contrary to recommendations, such as less frequent modeling of healthy eating and physical activity, more control of child feeding, and fewer family meals. Mothers reporting poor-quality sleep tended to have lower parenting self-efficacy, poorer overall health status, more days of poor mental and physical health, greater depression, more stress, and higher BMIs. Future nutrition research should establish the directionality between sleep quality and health behaviors. Future interventions should help mothers develop strategies for improving sleep quality, such as increased physical activity and fruit and vegetable intake, and helping mothers realize how their sleep quality may affect parenting practices.

The Association Between Body Mass Index (BMI) and Sleep Duration: Where Are We after nearly Two Decades of Epidemiological Research?

Over the past twenty years we have seen a vast number of epidemiological studies emerge on the topic of obesity and sleep duration, with a focus on body mass index, as it is easy and cheap to measure and analyse. Such studies largely observe that cross-sectionally a higher BMI is associated with shorter sleep and that in longitudinal studies shorter sleep duration is associated with increases in BMI over time, but some research has found no relationship between the two. This narrative review is not exhaustive, but appraises the literature on sleep duration and BMI from perspectives that have previously been unexplored in a single paper. As such, I discuss research in these important areas: bidirectionality, objective vs. subjective sleep duration, how meaningful the effect sizes are and how we have begun to address causality in this area. From the evidence appraised in this review, it is clear that: (i) there is some modest evidence of a bidirectional relationship between BMI and sleep duration in both children and adults; (ii) objective measurements of sleep should be used where possible; (iii) it remains difficult to confirm whether the effect sizes are conclusively meaningful in a clinical setting, but at least in adults this so far seems unlikely; (iv) to date, there is no solid evidence that this relationship (in either direction) is in fact causal. In the near future, I would like to see triangulation of these findings and perhaps a move towards focusing on distinct aspects of the relationship between obesity and sleep that have not previously been addressed in detail, for various reasons.

Position of the Academy of Nutrition and Dietetics: Benchmarks for Nutrition in Child Care

It is the position of the Academy of Nutrition and Dietetics that early care and education (ECE) programs should achieve recommended benchmarks to meet children's nutrition needs and promote children's optimal growth in safe and healthy environments. Children's dietary intake is influenced by a number of factors within ECE, including the nutritional quality of the foods and beverages served, the mealtime environments, and the interactions that take place between children and their care providers. Other important and related health behaviors that may influence the development of obesity include children's physical activity, sleep, and stress within child care. Recent efforts to promote healthy eating and improve other health behaviors in ECE include national, state, and local policy changes. In addition, a number of interventions have been developed in recent years to encourage healthy eating and help prevent obesity in young children in ECE. Members of the dietetics profession, including registered dietitian nutritionists and nutrition and dietetics technicians, registered, can work in partnership with ECE providers and parents to help promote healthy eating, increase physical activity, and address other important health behaviors of children in care. Providers and parents can serve as role models to support these healthy behaviors. This Position Paper presents current evidence and recommendations for nutrition in ECE and provides guidance for registered dietitian nutritionists; nutrition and dietetics technicians, registered; and other food and nutrition practitioners working with parents and child-care providers. This Position Paper targets children ages 2 to 5 years attending ECE programs and highlights opportunities to improve and enhance children's healthy eating while in care.

Meeting the 24-hr movement guidelines: An update on US youth with autism spectrum disorder from the 2016 National Survey of Children's Health

The purpose of this study was to examine how adherence to the physical activity (PA), screen-time (ST), and sleep duration guidelines differ between youth with autism spectrum disorder (ASD) and youth with typical development (TD). A secondary objective was to assess how PA, ST, and sleep duration varied among youth with ASD by age and ASD severity. Utilizing the 2016 National Survey of Children's Health data, parental reports of time spent by youth in PA, ST, and sleep were used to determine adherence to the 24-hr movement guidelines for 1008 youth with ASD and 34 489 youth with TD. Multivariate logistic regression analyses determined that children with ASD were less likely to meet the guidelines for PA, ST, and sleep duration, and adolescents with ASD were less likely to meet the guidelines for PA and ST than participants with TD. Furthermore, logistic regression analyses determined adolescents with severe ASD to be less likely to meet the sleep guideline compared to adolescents with mild ASD. Overall, youth with ASD were significantly less likely to adhere to all three guidelines. The findings highlight the breadth of health behaviors that require intervention to counteract the poorer health status among youth with ASD. Autism Res 2019, 12: 941-951. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: New health recommendations suggest children and adolescents should have at least 1 hr of physical activity, no more than 2 hr of screen-time (e.g., television), and 9-11 hr of sleep (or 8-10 hr for children aged 14 or older) every day. This article looked at how children and adolescents with autism meet these new guidelines. The two main results were that: (a) children with autism were less likely to meet all three guidelines compared to children without autism, and (b) adolescents with autism were less likely to meet the guidelines for physical activity and screen-time.

Beyond Access and Exposure: Implications of Sneaky Media Use for Preschoolers' Sleep Behavior

Greater consumption of and access to screen media are known correlates of unhealthy sleep behavior in preschoolers. What remains unknown, however, is the role a child's media use plays in this association. Parents and guardians of U.S. preschoolers (N = 278, average child age 56 months) provided information about their child's nightly duration of sleep, daily duration of nap, quantity of screen media use, sneaky media use, and the presence of a screen media device in the bedroom. We assessed four media: television, DVD/VCRs, video games, and computer/Internet. Based on rationales of sleep displacement, the forbidden fruit hypothesis, and social cognitive theory, we predicted that increased consumption of and access to media, along with sneaky media use, would predict a shorter duration of nightly sleep and longer duration of daily nap across the four screen media. In correlational analyses, a clear pattern emerged with quantity of media use, screen media in the bedroom, and sneaky media use associated with shorter nightly duration of sleep and longer duration of daily nap. In regression analyses, only weekday evening television viewing and sneaky media use predicted shorter nightly sleep duration; weekend morning and evening DVD use predicted longer naps.

The Combined Impact of Sleep and Diet on Adiposity in Infants, Toddlers, and Young Children: A Systematic Review

OBJECTIVE

Short sleep duration and poor dietary habits may contribute to increased adiposity; however, the impact of the interaction between these variables on adiposity is less understood. To evaluate research investigating the combined effects of sleep and diet on adiposity in infants, toddlers, and young children.

METHODS

Systematic searches of electronic databases (PubMed, CINAHL, and Web of Science) from inception through April 2017 were conducted. All studies published in English that had at least 1 sleep (e.g., sleep duration and night awakenings), diet (e.g., 24-hour diet recall and breastfeeding duration), and adiposity (e.g., body mass index z-score and weight-for-length) measure were eligible for inclusion. Abstract and full-text article reviews were conducted by 2 independent reviewers. Data were extracted into a standardized spreadsheet.

RESULTS

Of the 17 full-text articles reviewed, 14 studies were included. Mediation (n = 2) and moderation (n = 2) were seldom used. Investigation of the combined effects of sleep and diet on adiposity demonstrated a substantial lack of evidence. Synthesis of articles suggests that the relationship between sleep and diet may be interactive and their effects additive in their impact when targeted simultaneously within interventions.

CONCLUSION

Without consideration of interaction effects among variables of interest, a substantial gap in the literature persists. Both diet and sleep need to be assessed simultaneously and repetitively in future longitudinal research.

Childhood obesity: increased risk for cardiometabolic disease and cancer in adulthood

Prevalence of childhood obesity has worldwide more than doubled since 1980. Underlying factors are complex and are far from completely understood. Strategies to prevent childhood obesity have mainly focused on behavioral intervention; and obesity therapy was mainly based on lifestyle modification to date. However, effects for both have been quite limited so far and no country has succeeded in fighting the obesity epidemy we are facing. Normalization of body weight before onset of puberty is crucial for several reasons: First, obese children and adolescents frequently stay obese until adulthood. Second, obesity during adolescence is significantly associated with increased risk for cardiovascular and metabolic disease such as type 2 diabetes in adulthood. And third, recent data have shown a strong association between higher body mass index (BMI) during adolescence and increased risk for several malignancies such as leukemia, Hodgkin's disease, colorectal cancer, breast cancer and others in adulthood. This review summarizes our current understanding of epidemiology, underlying factors, concomitant disease, as well as available intervention strategies and gives an overview of what has been reached so far and what measures should be undertaken to counteract the obesogenic environment.

Sleep, energy balance, and meal timing in school-aged children

OBJECTIVE

To determine associations among objectively-measured nocturnal sleep time, bedtime and obesogenic behaviors, including dietary intake, timing of intake, and physical activity, in a diverse sample of school-aged children who presented for behavioral treatment to enhance sleep duration.

METHODS

Eighty-seven children (8-11 y, 66.7% female, zBMI: 0.86 ± 1.0) who self-reported sleeping <9.5 h/night were studied for one week using wrist actigraphy to estimate sleep; hip-worn accelerometers to measure physical activity; and 24 h dietary recalls to capture dietary intake and meal timing. Pearson and Spearman's rho correlations and linear regressions controlling for age, gender and race were used for statistical analyses.

RESULTS AND CONCLUSION

Mean bedtime was 10:31 PM (±58.2 min) and mean nocturnal sleep time was 7.7 h (±37.5 min). Although later bedtime was associated with shorter sleep time (r = -0.61, p < 0.001), the two variables were differentially related to obesity risk factors. Later bedtime, but not sleep time, correlated with greater daily fat intake, later first meal of the day, and greater after-dinner intake (all p < 0.05). Nocturnal sleep time, but not bedtime, correlated with zBMI (p = 0.04). Both sleep time and later bedtime were associated with a later last meal of the day (all p < 0.05). Findings remained consistent after controlling for demographic factors. In short-sleeping school-aged children, bedtime may be more predictive of dietary obesity risk factors whereas sleep duration may be more predictive of zBMI. Results suggest that health providers should consider both bedtime and sleep duration for reducing obesity risk in children.

CLINICAL TRIAL

Enhancing Sleep Duration: Effects on Children's Eating and Activity Behaviors, NCT03186508, https://clinicaltrials.gov/ct2/show/NCT03186508.

Multi-etiological Perspective on Child Obesity Prevention

PURPOSE OF REVIEW

The simple energy balance model of obesity is inconsistent with the available findings on obesity etiology, prevention, and treatment. Yet, the most commonly stated causes of pediatric obesity are predicated on this model. A more comprehensive biological model is needed upon which to base behavioral interventions aimed at obesity prevention. In this light, alternative etiologies are little investigated and thereby poorly understood.

RECENT FINDINGS

Three candidate alternate etiologies are briefly presented: infectobesity, the gut microbiome, and circadian rhythms. Behavioral child obesity preventive investigators need to collaborate with biological colleagues to more intensively analyze the behavioral aspects of these etiologies and to generate innovative procedures for preventing a multi-etiological problem, e.g., group risk analysis, triaging for likely causes of obesity.

Insufficient Sleep Duration And Its Association With Breakfast Intake, Overweight/Obesity, Socio-Demographics And Selected Lifestyle Behaviors Among Saudi School Children

OBJECTIVE

Adequate sleep is an important factor for maintaining good health among children. However, there have been few studies reporting on the association of sleep duration with breakfast intake frequency. This study examined the prevalence of nocturnal sleep duration among Saudi children and its association with breakfast intake, screen time, physical activity levels and socio-demographic variables.

METHODS

A multistage stratified cluster random sampling technique was used to select 1051 elementary school children in Riyadh. Weight and height were measured and body mass index was computed. The sleep duration, daily breakfast intake frequency, socio-demographic and lifestyle behaviors were assessed using a specifically designed self-reported questionnaire filled by the children's parents.

RESULTS

Over 71% of the Saudi school children did not attain the recommended sufficient sleep duration at night. Results of logistic regression analysis, adjusted for confounders, exhibited significant associations between longer sleep duration and younger age (aOR=1.12, p=0.046), being female (aOR=1.39, p=0.037), higher father educational levels, daily breakfast intake (aOR=1.44, p=0.049) and lower screen time (aOR for >2 hrs/day=0.69, p=0.033). However, no significant (p> 0.05) association was found for mother education, family income, number of family member in the house, overweight/obesity, or physical activity levels.

CONCLUSION

The prevalence of insufficient nocturnal sleep among Saudi children was high. Insufficient sleep was associated with breakfast and several important socio-demographic and lifestyle behaviors. The findings of this study support the development of interventions to prevent insufficient sleep and help Saudi children improve their sleeping habits.

A review of developmental consequences of poor sleep in childhood

Sleep is a fairly diverse and complex construct to operationalize in a scientific and naturalistic context. We report a systematic review and meta-analysis of reviews published in the last 5 years on poor sleep and developmental outcomes. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, 42 articles (or 1117 studies) qualified. They reported outcomes related to poor sleep investigated as sleep disorders (38.1%), sleep 'in general' (26.2%), sleep duration (23.8%), in terms of circadian rhythm (4.8%), intra-individual variability (2.4%), and napping (2.4%). Sleep was primarily subjectively reported (30.2%), yet the methodology of sleep assessment was often neither tabulated nor discussed. Overall, most papers had a health-scope, being primarily weight problems expressed as body mass index. Its relationship with performance was measured with the Wechsler intelligence tests, the child behavior checklist and the continuous performance test, whereas meta-analytic papers specifically focused on cognition with sleep disorder (i.e. sleep-disordered breathing; 38.6%), on health (i.e. weight) with sleep duration (25%) and behavior with sleep 'in general' (15.9%), having a high true variance. Nevertheless, an aggregated effect size d of 0.35 (95% confidence interval: 0.27-0.42) suggests that poor sleep is moderately affecting a child's performance and health. In conclusion, poor sleep can no longer be disregarded, yet methodologies that are more rigorous and a scope beyond health may foster a better understanding of the role of (poor) sleep across childhood neurodevelopment.

Childhood obesity research at the NIH: Efforts, gaps, and opportunities

Childhood obesity is a major public health challenge. This article describes an overview of the National Institutes of Health (NIH) behavioral and social sciences childhood obesity research efforts. The overview will highlight five areas of childhood obesity research supported by the NIH: (a) basic behavioral and social sciences; (b) early childhood; (c) policies, programs, and environmental strategies; (d) health disparities; and (e) transagency and public-private collaboration. The article also describes potential gaps and opportunities in the areas of childhood obesity and severe obesity, measurement, and sleep.

Unhealthy eating habits around sleep and sleep duration: To eat or fast?

Traditionally, breakfast skipping (BS), and recently late-night dinner eating (LNDE), have attracted attention in public health because they can predispose to cardiometabolic conditions such as obesity and type 2 diabetes. Intriguingly, it has become evident that short duration of sleep elicits similar health risks. As LNDE, BS, and short sleep can be closely related and can aggravate each other, these three should not be considered separately. In this context, LNDE (or its equivalents, snacking or heavy alcohol consumption after dinner) and BS may be representative unhealthy eating habits around sleep (UEHAS). While it is important to take energy in the early morning for physical and intellectual activities, attaining a fasting state is essential for metabolic homeostasis. Our previous UEHAS studies have shown that BS without LNDE, i.e., BS alone, is not associated with obesity and diabetes, suggesting the possibility that BS or taking a very low energy breakfast, which could yield fasting for a while, may prevent obesity and diabetes in people with inevitable LNDE. Further studies considering UEHAS and short sleep simultaneously are needed to elucidate the effects of these unhealthy lifestyles on cardiometabolic diseases.

Insufficient Sleep Duration Is Associated With Dietary Habits, Screen Time, and Obesity in Children

STUDY OBJECTIVES

To examine sleep duration and the association between insufficient sleep duration and life- style factors in a representative sample of Greek children and adolescents.

METHODS

Population data derived from a school-based health survey carried out in spring 2015 on 177,091 children (51% male) aged 8 to 17 years (participation rate was approximately 40% of the total population). Dietary habits, sleeping hours (weekdays and weekend), physical activity status, and sedentary activities were assessed through electronic questionnaires completed at school with assistance of teachers. Anthropometric and physical fitness measurements were obtained by physical education teachers.

RESULTS

A greater proportion of males than females (42.3% versus 37.3%, P < .001) and of children compared with adolescents (42.1% versus 32.8%, P < .001) reported insufficient sleep duration. Insufficient sleep duration was associated with unhealthy dietary habits such as skipping breakfast (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.25-1.35), fast-food consumption (OR 1.35, 95% CI 1.29-1.41), and consuming sweets regularly (OR 1.32, 95% CI 1.25-1.39). Insufficient sleep duration was found to be associated with insufficient dietary habits (OR 0.59, 95% CI 0.54-0.64), increased screen time (OR 1.26, 95% CI 1.21-1.31), and being overweight/obese (OR 1.21, 95% CI 1.17-1.25), after adjusting for several covariates.

CONCLUSIONS

Insufficient sleep duration was associated with an unhealthy lifestyle profile among children and adolescents in this study. Results support the development of interventions to help students improve sleep duration.

Overnight sleep duration and obesity in 2-5 year-old American Indian children

BACKGROUND

Sleep has emerged as a potentially modifiable risk factor for obesity in children.

OBJECTIVES

The purpose of this investigation was to evaluate the association between overnight sleep duration and obesity among American Indian (AI) children ages 2-5 years.

METHODS

Data were examined from the baseline assessment of children enrolling in the Healthy Children, Strong Families study, which is a randomized lifestyle intervention trial in five diverse rural and urban AI communities nationally among children ages 2-5 years. Multivariable models were built to assess the relationship between sleep duration and BMI z-score while controlling for potential sociodemographic and behavioural covariates.

RESULTS

Three hundred and ninety-eight children had sufficient data to be included in analysis. In multivariable models controlling for potential covariates, overnight sleep duration was significantly and inversely associated with BMI z-score (B = -0.158, t = -1.774, P = 0.006). Similarly, when controlling for covariates, children who slept 12 or more hours had significantly lower BMI z-scores compared with those who slept 8 to 10 h (P = 0.018) or less than 8 h (P = 0.035); the difference between 12+ hours and 10 to 12-h groups did not reach statistical significance (P = 0.073) but supported a linear relationship between overnight sleep duration and BMI. Weekday-to-weekend variability in overnight sleep duration was not associated with BMI z-score (B = 0.010, t = 0.206, P = 0.837).

CONCLUSIONS

Overnight sleep duration is independently and inversely related to BMI z-score among AI children ages 2-5 years, even when controlling for important sociodemographic and obesogenic lifestyle factors. This represents the first report, to our knowledge, of sleep duration as a risk factor for obesity among AI children.

Chronic sleep deprivation and gender-specific risk of depression in adolescents: a prospective population-based study

BACKGROUND

Chronic exposure to sleep deprivation may increase the risk of depression in young people who are particularly vulnerable to changes in sleep and mental health. Sleep deprivation and incident depression may also differ by gender. We investigated the prospective association between cumulative sleep deprivation and subsequent levels of depressive symptomatology among adolescents from a gender perspective.

METHODS

A longitudinal study of 3071 young people in the British Columbia Adolescent Substance Use Survey (BASUS) cohort with three sleep time and two depression measures over 12 months (2011-12). Multivariable linear regression models with interaction terms estimated gender-specific associations between self-reported chronic sleep deprivation and changes in depressive symptomatology; post-estimation analysis calculated adjusted mean depression scores for each level of cumulative sleep deprivation.

RESULTS

Cumulative sleep deprivation was associated with a monotonic increase in depression scores at follow-up in young women, but no consistent pattern was seen in young men. During follow-up, 15% of young women were chronically sleep deprived and 29% were depressed (CESD ≥24). Young women reporting chronic exposure to sleep deprivation had higher CESD scores at follow-up (21.50 points, [CI95 19.55-23.45]), than those reporting no history (16.59 [15.72-17.45]); that remained after multivariable adjustment (19.48 [17.59-21.38]).

CONCLUSION

Results suggested that chronic sleep deprivation increases the risk of major depression among young women. Mental health promotion for young people should include relevant strategies to ensure young women can achieve recommended amounts of sleep.

Insufficient Sleep Duration and Overweight/Obesity among Adolescents in a Chinese Population

OBJECTIVES

The objective of this study was to investigate the relationship between sleep duration and overweight/obesity among Chinese adolescents.

METHODS

A school-based cross-sectional study was conducted among Chinese adolescents in 2016. In total, 2795 school-aged Chinese children aged 12 to 13 years participated in this study. Participants were asked to complete self-administered surveys during a 45-min class period in their classroom. Details of the questionnaire about health-related behaviors included sleep habits, physical activity, screen time, cigarette use, and alcohol use. Height, weight, waist circumference and hip circumference were directly measured.

RESULTS

The mean sleep duration was 8.7 h/day. In total, 43.0% of the participants had a sleep duration of less than 9 h/day. Sleep duration was significantly inversely related to BMI, waist circumference, hip circumference and WHtR in multiple linear regression analyses in both genders. Logistic regression models showed that insufficient sleep (<9 h/day) was associated with high odds of overweight/obesity among both young boys and girls.

CONCLUSIONS

Insufficient sleep duration was associated with overweight/obesity in Chinese adolescents, and short sleep duration was probably associated with central adiposity, especially among boys.

Sleep, Circadian Rhythms, and Risk Across Health Domains in Adolescents With an Evening Circadian Preference

Sleep and circadian rhythm changes during adolescence contribute to increased risk across emotional, behavioral, cognitive, social, and physical health domains. This study examines if sleep and dim light melatonin onset (DLMO) are related to greater risk in these 5 health domains. Participants were 163 (93 female, age = 14.7 years) adolescents with an evening circadian preference from a study funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Sleep and circadian measures included weekday total sleep time (TST), bedtime, and shut-eye time assessed via sleep diary, the Children's Morningness-Eveningness Preferences scale, and DLMO. Health domains included self-reported emotional, cognitive, behavioral, social, and physical health. Later DLMO was significantly associated with shorter weekday TST, later weekday bedtime, and later weekday shut-eye time, as well as lower risk in the behavioral domain. At the trend level, later DLMO was related to fewer physical health problems. Earlier DLMO combined with a later bedtime, later shut-eye time, or shorter TST predicted greater risk in the cognitive domain. Later DLMO and shorter TST or a later bedtime predicted worse physical health. DLMO timing was not related to the emotional or social domain. There is evidence that a discrepancy between sleep behaviors and the endogenous circadian rhythm may be related to risk in the cognitive domain for adolescents with an evening circadian preference. Preliminary evidence also indicated that a delayed DLMO and shorter TST or a later bedtime may be related to vulnerability to physical health risk.

Association of sleep duration and quality with blood lipids: a systematic review and meta-analysis of prospective studies

OBJECTIVES

To assess the longitudinal evidence of the relationships between sleep disturbances (of quantity and quality) and dyslipidaemia in the general population and to quantify such relationships.

SETTING

Systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

METHODS

We performed a systematic search of PubMed and Embase (up to 9 September 2017), complemented with manual searches, of prospective population studies describing the association between sleep duration and quality and the incidence of dyslipidaemias. Relative risks (95% CIs) were extracted and pooled using a random effects model. Subgroup analyses by lipid type were performed. Heterogeneity and publication bias were also assessed. Quality was assessed with Downs and Black score.

PARTICIPANTS

Studies were included if they were prospective, had measured sleep quantity and/or quality at baseline and either incident cases of dyslipidaemia or changes in blood lipid fractions assessed prospectively.

PRIMARY OUTCOME MEASURES

Incidence of dyslipidaemia and changes in lipid fractions. Dyslipidaemia was defined as a high total cholesterol, triglycerides, low-density lipoprotein cholesterol or low high-density lipoprotein cholesterol compared with the reference group.

RESULTS

Thirteen studies were identified (eight using sleep duration, four sleep quality and one both). There was heterogeneity in the sleep quality aspects and types of lipids assessed. Classification of sleep duration (per hour/groups) also varied widely. In the pooled analysis of sleep duration (6 studies, 16 cohort samples; 30 033 participants; follow-up 2.6-10 years), short sleep was associated with a risk of 1.01 (95% CI 0.93 to 1.10) of developing dyslipidaemia, with moderate heterogeneity (I2=56%, P=0.003) and publication bias (P=0.035). Long sleep was associated with a risk of 0.98 (95% CI 0.87 to 1.10) for dyslipidaemia, with heterogeneity (I2=63%, P<0.001) and no significant publication bias (P=0.248).

CONCLUSION

The present analysis was unable to find supportive evidence of a significant relationship between sleep duration and the development of dyslipidaemia. However, heterogeneity and small number of studies limit the interpretation.

PROSPERO REGISTRATION NUMBER

CRD42016045242.

Partial Sleep Deprivation Reduces the Efficacy of Orexin-A to Stimulate Physical Activity and Energy Expenditure

OBJECTIVE

Sufficient sleep is required for weight maintenance. Sleep deprivation due to noise exposure stimulates weight gain by increasing hyperphagia and reducing energy expenditure (EE). Yet the mechanistic basis underlying the weight gain response is unclear. Orexin-A promotes arousal and negative energy balance, and orexin terminals project to the ventrolateral preoptic area (VLPO), which is involved in sleep-to-wake transitions. To determine whether sleep deprivation reduces orexin function in VLPO and to test the hypothesis that sleep deprivation would attenuate the orexin-A-stimulated increase in arousal, physical activity (PA), and EE.

METHODS

Electroencephalogram, electromyogram, distance traveled, and EE were determined in male Sprague-Dawley rats following orexin-A injections into VLPO both before and after acute (12-h) and chronic (8 h/d, 9 d) sleep deprivation by noise exposure.

RESULTS

Orexin-A in the VLPO significantly increased arousal, PA, total EE, and PA-related EE and reduced sleep and respiratory quotient before sleep deprivation. In contrast to after acute sleep deprivation in which orexin-A failed to stimulate EE during PA only, orexin-A failed to significantly increase arousal, PA, fat oxidation, total EE, and PA-related EE after chronic sleep deprivation.

CONCLUSIONS

Sleep deprivation may reduce sensitivity to endogenous stimuli that enhance EE due to PA and thus stimulate weight gain.

Association Between Sleep Duration and Body Mass Index Among US Low-Income Preschoolers

OBJECTIVE

To verify whether sleep duration was related to body mass index z scores (zBMI) and whether bedtimes or ethnicity was a moderator of the sleep duration-zBMI association among preschoolers from low-income families.

METHODS

Two hundred twenty-eight African American and Hispanic parents and their preschoolers were recruited from Head Start Centers. Parents reported their preschoolers' sleep duration and bedtimes (using the Children's Sleep Habits Questionnaire) and their television watching. Food intake was measured using multiple days of digital photography to estimate energy intake at dinner. The Parenting Stress Index and the Center for Epidemiologic Studies Depression Scale were used to measure stress and depression. Parents' and preschoolers' height and weight were measured by trained staff.

RESULTS

Longer sleep duration was significantly associated with lower zBMI when controlling for demographics, bedtimes, energy intake at dinner, and television watching, but not when also controlling for parents' demographics, BMI, stress, and depression. Preschoolers' sleep duration-zBMI association was not moderated by bedtimes or ethnicity.

CONCLUSIONS

Longer sleep duration was associated with lower zBMI among low-income preschoolers when controlling for preschoolers' characteristics, but this was no longer the case when also controlling for parents' characteristics. Additional studies are needed on the moderators of the sleep duration-zBMI association among low-income preschoolers.

Past, present, and future: trends in sleep duration and implications for public health

Sleep is important for the physical, social and mental well-being of both children and adults. Over the years, there has been a general presumption that sleep will inevitably decline with the increase in technology and a busy 24-hour modern lifestyle. This narrative review discusses the empirical evidence for secular trends in sleep duration and the implications of these trends.

Associations between sleep duration and physical activity and dietary behaviors in Chinese adolescents: results from the Youth Behavioral Risk Factor Surveys of 2015

OBJECTIVE

To assess the association between sleep duration and physical activity and dietary behaviors among adolescents in a representative sample.

METHODS

The analysis was performed using data from the 2015 Ningbo Youth Risk Behavior Survey. Associations between physical activity and dietary behaviors and sleep duration were examined on weighted data using logistic regression.

RESULTS

Of the 10726 students, roughly 40% reported sleep duration <8 h. Longer sleep duration was associated with higher likelihood of milk intake, fruit consumption, vegetable consumption, water consumption, moderate physical activity, and muscle-strengthening physical activity, and with a lower likelihood of cigarette use, alcohol use, sweets intake, Western fast food intake, and breakfast skipping.

CONCLUSION

Insufficient sleep may be common among Chinese adolescents. Sleep duration was associated with dietary behaviors, physical activity, and other health-related behaviors. These findings suggest that sleep duration could be a potential target for many health-risk behaviors in young adolescents.

Sleep duration and obesity in children: A systematic review and meta-analysis of prospective cohort studies

AIM

Childhood obesity is a major public problem worldwide, and sleep duration may be associated with childhood obesity. We conducted a systematic review and meta-analysis of prospective cohort studies to estimate the associations between sleep duration and obesity/body mass index (BMI) in children.

METHODS

PubMed, Embase and the Cochrane Library were searched. For the meta-analysis, the pooled relative risk (RR) and 95% confidence intervals (CI) were estimated to reveal the association between short sleep duration and obesity. For the review, the outcomes focused on BMI change or subsequent BMI status.

RESULTS

A total of 12 studies (15 populations) met the criteria for inclusion in the meta-analysis. Short sleep duration was significantly associated with obesity (RR: 1.45; 95% CI: 1.14-1.85). After excluding two cohorts that substantially affected the heterogeneity, the pooled results remained significant (RR: 1.30; 95% CI: 1.20-1.42), and the association was not substantially altered in the subgroup analysis. In addition, we summarised 24 studies that met the criteria for our review of the relationship between sleeping and BMI.

CONCLUSION

The present meta-analysis indicated that short sleep duration increased the risk of childhood obesity. Public health efforts that encourage children to have sufficient sleep time may be important in combating obesity.

Effectiveness of interventions on physical activity in overweight or obese children: a systematic review and meta-analysis including studies with objectively measured outcomes

There is no consensus on interventions to be recommended in order to promote physical activity among overweight or obese children. The objective of this review was to assess the effects on objectively measured physical activity, of interventions promoting physical activity among overweight or obese children or adolescents, compared to no intervention or to interventions without a physical activity component. Publications up to December 2015 were located through electronic searches for randomized controlled trials resulting in inclusion of 33 studies. Standardized mean differences from baseline to post-intervention and to long-term follow-up were determined for intervention and control groups and meta-analysed using random effects models. The meta-analysis showed that interventions had no effect on total physical activity of overweight and obese children, neither directly post-intervention (-0.02 [-0.15, 0.11]) nor at long-term follow-up (0.07 [-0.27, 0.40]). Separate analyses by typology of intervention (with or without physical fitness, behavioural or environmental components) showed similar results (no effect). In conclusion, there is no evidence that currently available interventions are able to increase physical activity among overweight or obese children. This questions the contribution of physical activity to the treatment of overweight and obesity in children in the studied interventions and calls for other treatment strategies.