Longitudinal association between short sleep, body weight, and emotional and learning problems in Hispanic and Caucasian children

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.

Sleep Disorders in Early Childhood and the Development of Mental Health Problems in Adolescents: A Systematic Review of Longitudinal and Prospective Studies

The association between sleep problems, particularly sleep disorders, and mental health has long been studied and recognized. However, the causal relationship between sleep disorders, particularly during early childhood, on mental health problems in adolescence are yet to be established. From a preventive perspective, it is important to understand the causality of mental health problems in adolescents so that intervention measures can be derived and implemented as early as possible for maximum effectiveness. To provide more precise information on the effect of early childhood sleep disorders on mental health problems during adolescence, a systematic review was conducted on longitudinal and prospective studies reported in the literature. Following the PRISMA guidelines with an extensive search of the literature 26 studies were identified. Seven of these identified studies satisfied all selection criteria with sufficient data on the effect of early childhood sleep disorders and mental health problems in adolescence. Information was extracted and analyzed systematically from each study and tabulated. The overall results obtained from these studies indicate a significant and possible causal relationship between early childhood sleep disorders and the development of mental health problems, such as anxiety, depression, and ADHD in adolescence. These results are discussed with regards to the theoretical and practical implications as well as preventive strategies.

Longitudinal associations between facets of sleep and adiposity in youth

OBJECTIVE

Beyond sleep duration, other facets of sleep such as variability and timing may be associated with obesity risk in youth. However, data are limited. Using a longitudinal design, this study tested whether multiple facets of sleep were associated with fat mass gain over 1 year.

METHODS

A convenience sample of non-treatment-seeking youth (age 8-17 years) wore actigraphy monitors for 14 days. Average weekly sleep duration, within-person sleep duration variability, weekend catch-up sleep, bedtime and wake time shift, social jet lag, bedtime, wake time, and sleep midpoint were calculated. The association of each facet of baseline sleep with 1-year fat mass, adjusting for baseline fat mass and height, was examined.

RESULTS

A total of 137 youths (54.0% female; mean [SD], age 12.5 [2.6] years; 28.4% non-Hispanic Black or African American; baseline fat mass = 15.3 [8.9] kg; 1-year fat mass = 17.0 [10.0] kg; 28.5% with baseline overweight or obesity) were studied. Wake time (p = 0.03) and sleep midpoint (p = 0.02) were inversely associated with 1-year fat mass, such that earlier wake time and midpoint were associated with higher 1-year fat mass. No other facet of sleep was significantly associated with 1-year fat mass (p > 0.09).

CONCLUSIONS

Using objective measures, youth with earlier wake times and sleep midpoints had greater gains in fat mass. Additional research is needed to determine whether sleep timing may be a modifiable target to prevent pediatric obesity.

Is self-reported short sleep duration associated with obesity? A systematic review and meta-analysis of cohort studies

CONTEXT

A possible association between self-reported short sleep duration and risk of obesity has been studied.

OBJECTIVE

To analyze the association between sleep duration and obesity.

METHODS

The LILACS, Medline, Central, Embase, and OpenGrey databases were searched from inception until July 2020. Two authors screened the studies independently according to the PECO strategy, as follows: participants: > 18 years old; exposure: short sleep duration; control: regular sleep; outcome: obesity). Only cohort studies were included. A total of 3286 studies were retrieved with the search strategy, but only 36 were included. Disagreements were resolved by a third author. The quality of studies was assessed with Newcastle-Ottawa Quality Assessment Form for Cohort Studies. The certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Thirty-six studies were included, and 22 contributed quantitative data. Most of the studies (n = 27) assessed sleep by self-report. The meta-analysis showed a significant association between self-reported short sleep and development of obesity, and the chances of developing obesity increased when self-reported sleep duration decreased.

CONCLUSIONS

Self-reported short sleep was significantly associated with a higher incidence of obesity, with moderate quality of evidence.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019130143.

Sleep duration, physical activity, and caloric intake are related to weight status in Mexican American children: a longitudinal analysis

BACKGROUND

Obesity is a serious issue, spanning all ages, and, in the U.S., disproportionately affects Latinos and African Americans. Understanding sleep, physical activity and dietary behaviors that may predict childhood obesity can help identify behavioral intervention targets.

METHODS

Data were drawn from a U.S. cohort study of 323 Mexican American 8-10-year-old children and their mothers, who participated in a longitudinal study over a 2-year period. Measures were collected at baseline (BL; child mean age = 8.87, SD = 0.83), year 1 (FU1) and year 2 (FU2). Mothers reported on household income and acculturation at BL. Child height and weight were collected and BMI z-scores (BMIz) were calculated for weight status at BL, FU1, and FU2. Accelerometer-estimated sleep duration (hours) and moderate-to-vigorous physical activity (MVPA; minutes) were collected across 3 days at BL, FU1, and FU2. Two 24-h dietary recalls were performed at each time point; from these, average energy intake (EI, kcals/day) was estimated. Cross-lagged panel analysis was used to examine behavioral predictors on BMIz at each time point and across time.

RESULTS

At BL and FU1, longer sleep duration (β = - 0.22, p < 0.001; β = - 0.17, p < 0.05, respectively) and greater MVPA (β = - 0.13, p < 0.05; β = - 0.20, p < 0.01, respectively) were concurrently related to lower BMIz. At FU2, longer sleep duration (β = - 0.18, p < 0.01) was concurrently related to lower BMIz, whereas greater EI (β = 0.16, p < 0.01) was related to higher BMIz. Longer sleep duration at BL predicted lower BMIz at FU1 (β = - 0.05, p < 0.01).

CONCLUSIONS

Longer sleep duration was concurrently related to lower weight status at each time point from ages 8-10 to 10-12. Higher MVPA was concurrently related to lower weight status in earlier childhood (ages 8-10 and 9-11) and higher EI was concurrently related to higher weight status toward the end of childhood (ages 10-12 years). Furthermore, longer sleep in earlier childhood was protective of children's lower weight status 1 year later. These findings suggest that sleep duration plays a consistent and protective role against childhood obesity; in addition, MVPA and healthy EI remain important independent factors for obtaining a healthy weight.

Sleep Assessment for Sleep Problems in Children

The breadth of childhood sleep problems is broad and can be associated with biologic, psychiatric, behavioral, social, and environmental processes. Unrecognized childhood sleep problems may threaten daytime behaviors and negatively impact school and psychosocial functioning. Left unattended, overall child biopsychosocial development may be impaired. Thus, identifying and addressing sleep problems has potential to optimize childhood health, development, and overall well-being. Nurses need to be cognizant of detrimental impacts of child sleep deprivation and advocate for appropriate sleep assessments while offering sleep education to parents and children.

Weekday time in bed and obesity risk in adolescence

Introduction

Sleep curtailment is associated with obesity in children, but few studies have investigated this relationship in a longitudinal sample of adolescents. The aim of the present study was to examine the longitudinal association between weekday time in bed (TIB) at age 10–13 and overweight at age 16–19.

Methods

Adolescents and their parents (N = 3025 families), participating in a longitudinal population‐based study, completed questionnaires assessing habitual bedtime and wake time on weekdays, weight and height, socioeconomic status (SES), internalizing mental health problems and disturbed eating. Two surveys were administered with a 6‐year interval (T1 and T2). A one‐way analysis of covariance (ANCOVA) was performed examining the association between TIB and weight category 6 years later, with SES, internalizing problems and disturbed eating at baseline entered as covariates. Hierarchical and logistic regression analyses were used to assess TIB at age 10–13 years to as a predictor of body mass index (BMI) standardized deviation scores (SDS) and overweight status at age 16–19 adjusting for the same confounders and baseline BMI.

Results

A linear inverse relationship between TIB at age 10–13 and BMI category at age 16–19 was demonstrated by the ANCOVA, p < 0.001. Shorter TIB was related to higher weight, but the effect size was small (partial eta squared = 0.01). When adjusting for the included baseline confounders in the hierarchical regression model TIB significantly predicted later BMI SDS (β = −0.039, p = 0.02). The adjusted logistic regression model showed that for each hour reduction of TIB at T1 the odds of being overweight/obese at T2 increased with a factor of 1.6.

Conclusion

Shorter TIB was found to be a significant, yet modest, independent predictor of later weight gain in adolescence. The findings implicate that establishing healthy sleep habits should be addressed in prevention and treatment strategies for adolescent obesity.

Sleep duration and obesity in children and adolescents: evidence from an updated and dose-response meta-analysis

BACKGROUND AND OBJECTIVES

The association between sleep duration and obesity in children and adolescents has been widely evaluated, whereas the current findings are mixed and prospective studies are limited. To shed more light on this issue and explore the dose-response relationship, we performed the present updated meta-analysis by synthesizing the results of prospective cohorts.

METHODS

Literature retrieval, study selection and data extraction were completed independently and in duplicate. Effect-size estimates are expressed as relative risk (RR) with 95% confidence interval (CI) or standardized regression coefficient (β) with standard error.

RESULTS

Data from 33 articles, involving 57,848 children and adolescents, were meta-analyzed. Overall analyses revealed statistically significant associations of short (adjusted RR = 1.57, 95% CI: 1.36 to 1.81, P < 0.001) and long sleep duration (0.83, 0.75 to 0.93, 0.001) with obesity. Short sleep duration was also associated with significant changes in body mass index z-score (mean difference = -0.06; 95% CI: -0.09 to -0.04; P < 0.001). By contrast, long sleep duration was identified as a protective factor for childhood obesity. In dose-response analyses, short sleep duration was significantly associated with obesity in toddlers (1-2 years) (adjusted RR = 1.20, 95% CI: 1.07 to 1.34, P = 0.001), preschool-aged (3-5 years) children (1.58, 1.36 to 1.83, <0.001), and school-aged (6-13 years) children (1.82, 1.51 to 2.21, <0.001). In subgroup analyses, geographic region, sleep duration assessment, age, and follow-up interval were possible sources of heterogeneity.

CONCLUSIONS

Our findings indicate that short sleep duration can increase the risk of obesity in children and adolescents, especially within 3-13 years of age, and long sleep duration seemed beneficial in preventing obesity.

Physical Activity, Sleep, Body Mass Index, and Associated Risk of Behavioral and Emotional Problems in Childhood

OBJECTIVE

Cross-sectional data indicate that physical activity, longer sleep duration, and normal body weight are associated with better mental health in childhood. It is less clear whether these factors protect against future emotional and behavioral problems. We investigated whether physical activity, sleep duration, and body mass index (BMI) at the age of 7 years are associated with emotional and behavioral problems at the age of 11 years.

METHODS

Children born to European mothers enrolled in the prospective longitudinal Auckland Birthweight Collaborative Study (N = 871) were assessed at birth and ages 7 and 11 years. Physical activity and sleep duration were measured using accelerometer. BMI was calculated from height and weight measurement. Outcome variables assessed at the age of 11 years were parent and child self-report Strengths and Difficulties Questionnaire and parent and teacher Conners' Rating Scale scores.

RESULTS

Physical activity, sleep duration, and BMI at the age of 7 years were not significantly associated with emotional and behavioral problems at the age of 11 years. In cross-sectional analysis at the age of 11 years, there was no significant association between physical activity or sleep duration and emotional and behavioral problems. Children with a BMI in the overweight or obese range were significantly more likely to have teacher-rated behavior problems and parent-rated emotional or behavioral problems after adjustment for potential confounders.

CONCLUSION

Although physical activity and sleep have physical health benefits, they may not be protective against future emotional and behavioral problems in childhood in the general population. BMI in the obese or overweight range was significantly associated with current emotional and behavioral problems at the age of 11 years.

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.

Obesity and Circadian Cycle of Sleep and Wakefulness: Common Points and Prospects of Therapy

The prevalence of obesity in recent years has assumed the character of a non-communicable epidemic. Wherein, the standard approaches for its treatment are not always successful. Meanwhile, obesity remains one of the main causes of the formation of a number of some serious diseases, such as cardiovascular, diabetes, cancer, etc. and death from them. In search of alternative and more adequate methods of obesity treatment and preventing its complications, recent studies are aimed at further identifying new associations and revealing the pathophysiological mechanisms underlying excessive weight gain. It should be noted an increasing amount of chronobiological studies that raised awareness of the key role of the body’s circadian rhythms and its main regulator, melatonin, responsible for the temporary organization of the main physiological (including metabolism) processes throughout the 24-h day, in the development and progression of obesity. This review is devoted to the consideration of mutually directed interactions between the circadian system and metabolism; attempts have been made to explain the role of sleep-wake cycle disruptions in the excess accumulation of adipose tissue and the formation of obesity and its comorbidities, as well as detailed therapeutic principles based on normalizing disruption of body clocks using time-coordinated approaches to food intake, physical activity, the effects of non-drug methods and pharmacological substances (chronobiotics), which represents a novel and promising ways to prevent or treat obesity and associated diseases.

Association Between Sleep Duration, Obesity, and School Failure Among Adolescents

The aim of this study was to investigate the association between sleep duration, overweight/obesity, and school failure using data obtained from self-reported questionnaires completed by 13- to 15-year-olds in Sweden (n = 1,363; 50.7% female). The height and weight of the participants were measured by school nurses. A multiple logistic regression analysis was used to analyze the association between sleep duration and overweight/obesity, school failure, and perceived economic situation. A short sleep duration (<7 hr) was associated with overweight/obesity (p = .001), school failure (p = .007), and poorer perceived economic situation (p = .004). Modifying the sleep habits of adolescents is a potential target for obesity intervention as well as for improving school success. This information is particularly well suited for school nurses to disseminate to students and their parents.

Sleep patterns and sleep deprivation recorded by actigraphy in 4th-grade and 5th-grade students

OBJECTIVE

This study investigates sleep patterns of fourth- and fifth-grade students using actigraphy.

METHODS

The study included 257 students enrolled in a Southwestern US school district who participated in a novel sleep science curriculum during the Spring 2016-17 and Fall 2017-18 semesters and met the study inclusion criteria. As part of this curriculum, participants underwent 5-7 days of continuous wrist actigraphy and completed an online sleep diary.

RESULTS

Approximately two-thirds of the 9-11-year-old fourth- and fifth-grade students slept less than the minimum 9 h per night recommended by both the American Academy of Sleep Medicine/Sleep Research Society and the National Sleep Foundation. The sleep midpoint time on weekends was about 1 h later than on weekdays. There was a significant effect of age on sleep duration. Compared to 9-year old students, a larger proportion of 10-year old students had a sleep duration less than 8.5 h. Boys had shorter sleep duration than girls, and a larger percentage of boys obtained less than 9 h of sleep compared to girls.

CONCLUSIONS

Insufficient sleep is a highly prevalent condition among 9-11-year-old fourth- and fifth-grade elementary students. Importantly, there is a difference between sleep patterns on weekdays and weekends which may portend greater problems with sleep in adolescence and young adulthood.

Association Between Objectively Measured Sleep Duration and Symptoms of Psychiatric Disorders in Middle Childhood

Importance

The long-term association between sleep duration and mental health in children is currently unknown.

Objective

To investigate the prospective associations between sleep duration and symptoms of emotional and behavioral disorders at ages 6, 8, 10, and 12 years.

Design, Setting, and Participants

This population-based cohort study obtained data from the Trondheim Early Secure Study in Trondheim, Norway. A representative, stratified random sample of children born between January 1, 2003, and December 31, 2004, were invited to participate. Participants were followed up biennially from age 4 years (2007-2008) to 12 years (2013-2014). Data analysis was conducted from January 2, 2019, to May 28, 2019.

Main Outcomes and Measures

Sleep duration was assessed with 1 week of continuous use of a triaxial accelerometer. Symptoms of emotional (anxiety and depression) and behavioral (oppositional defiant, conduct, and attention-deficit/hyperactivity) disorders were measured by semistructured clinical interviews (using the Preschool Age Psychiatric Assessment and the Child and Adolescent Psychiatric Assessment) with parents (at all ages) and children (from age 8 years).

Results

The analytical sample comprised 799 children (mean [SD] age at time point 2, 6.0 [0.2] years; 405 [50.7%] boys; and 771 [96.5%] Norwegian). Shorter sleep duration at age 6 years (β [unstandardized regression coefficient] = -0.44; 95% CI, -0.80 to -0.08; P = .02) and 8 years (β = -0.47; 95% CI, -0.83 to -0.11; P = .01) forecasted symptoms of emotional disorders 2 years later. Comparatively short sleep duration at age 8 years (β = -0.65; 95% CI, -1.22 to -0.08; P = .03) and 10 years (β = -0.58; 95% CI, -1.07 to -0.08; P = .02) was associated with symptoms of behavioral disorders 2 years later among boys but not among girls at age 8 years (β = -0.14; 95% CI,- 0.52 to 0.24; P = .48) or 10 years (β = -0.05; 95% CI, = -0.49 to 0.40; P = .84). These associations were statistically significant among boys compared with girls at age 8 years (Δχ21 = 13.26; P < .001) and 10 years (Δχ21 = 10.25; P = .001). Symptoms of psychiatric disorders did not forecast sleep duration at any age.

Conclusions and Relevance

This study found an association between short sleep duration and increased risk of future occurrence of emotional disorder symptoms in both boys and girls and between reduced sleep and behavioral disorder symptoms in boys. These results suggest that improving sleep in children may help protect against the development of symptoms of common psychiatric disorders and may be advantageous in the treatment of such disorders.

Sleep duration and body mass index: moderating effect of self-perceived stress and age. Results of a cross-sectional population-based study

PURPOSE

The objective of this analysis was to assess whether the association between sleep duration and BMI and between sleep duration and waist circumference is moderated by age and self-perceived stress.

METHODS

We analyzed data from 2034 participants enrolled in 2014 in the cross-sectional study Obesity in Romania Study-study of the prevalence of obesity and related risk factors in Romanian general population (ORO study).

RESULTS

Interaction between sleep duration, self-perceived stress and age, with BMI as dependent variable, was statistically significant after adjustment for demographic and lifestyle factors (p value for interaction 0.003). In participants without self-perceived stress, a linear negative association between sleep duration and BMI was observed only in those 18-39 years old (p = 0.049), with BMI decreasing in parallel with increased sleep duration. In participants with self-perceived stress, a U-shaped relationship was observed between BMI and sleep duration in those 40-64 years old, with higher BMI in those sleeping ≤ 6 h and ≥ 9 h/night compared to those sleeping > 6 and < 9 h/night (p = 0.002 and 0.005). Those ≥ 65 years old with self-perceived stress sleeping ≥ 9 h/night had a significantly higher BMI compared to those in other sleep duration categories (p = 0.041 vs. those sleeping ≤ 6 h/night and p = 0.013 vs. to those sleeping > 6 and < 9 h/night). No interaction between age, self-perceived stress and sleep duration, with waist circumference as dependent variable was observed.

CONCLUSIONS

In our sample, the association between sleep duration and BMI was moderated by self-perceived stress and age.

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.

Sleep pattern, obesity and healthcare expenditures in Brazilian adults

The aim of this study was to analyze the relationship between sleep pattern and healthcare expenditures in adults, as well as to identify whether physical activity, biochemical markers and obesity affect this relationship. The sample was composed of 168 adults aged ≥ 50 years attended by two Basic Healthcare Units in Presidente Prudente, SP, Brazil. Health expenditure, sleep pattern, anthropometry, adiposity index, physical activity, metabolic and cardiovascular variables were assessed. Statistical analyses were performed using Kruskal-Wallis, Mann-Whitney and Spearman tests. Sleep disorders were positively correlated to higher costs with medicines and negatively correlated to costs with laboratory tests, even after adjusts by confounders. In addition, healthcare costs were also correlated to physical activity score, blood pressure, obesity and metabolic variables. Severe sleep disorders and high percentage of body fat were associated with increased use of medications. Sleep pattern is correlated to primary care healthcare costs, obesity and physical activity level.

Association between Sleep Habits and Problems and Internet Addiction in Adolescents

OBJECTIVE

This study examined the association between sleep habits and problems and Internet addiction in adolescents.

METHODS

Junior high school students from a local town in Japan (n=853; male/female, 425/428) were the subjects of this study, and were assessed for severity of Internet addiction and sleep habits and problems using the self-reported version of the Young's Internet Addiction Test (IAT) and Child and Adolescent Sleep Checklist (CASC).

RESULTS

The wake time on weekdays was not significantly different among the three groups; addicted, possibly-addicted, and non-addicted. In the addicted group, the total night sleep time was significantly shorter, and the bedtime was significantly delayed on both weekdays and weekends compared with those in the possibly-addicted and non-addicted groups. The wake time of the addicted group was significantly later than that of the other groups. The total scores of sleep problems measured by the CASC were significantly higher in the addicted and possibly-addicted groups than in the non-addicted group.

CONCLUSION

Internet addiction is strongly associated with sleep habits and problems in adolescents. These findings suggest that internet addiction should be considered while examining adolescent lifestyle.

Associations of Weekday and Weekend Sleep with Children's Reported Eating in the Absence of Hunger

Insufficient average sleep duration has been inconsistently associated with poor diet and obesity risks in youth. Inconsistencies in findings across studies may be due to a general failure to examine associations in weekday versus weekend sleep. We hypothesized that greater variations in weekday and weekend sleep duration would be associated with more disinhibited eating behaviors, which, in turn, might be involved in the relationship between sleep and weight. We, therefore, examined, among healthy, non-treatment seeking youth, the associations of average weekly, weekend, and weekday sleep duration with eating in the absence of hunger (EAH), a disinhibited eating behavior associated with disordered eating and obesity. Sleep was assessed via actigraphy for 14 days. Participants completed a self-report measure of EAH. Adiposity was measured by dual-energy X-ray absorptiometry. Linear regressions were used to test the associations of sleep duration with EAH and the associations of sleep duration and EAH, with fat mass. Among 123 participants (8–17 years, 52.0% female, and 30.9% with overweight), there was no significant association between average weekly sleep and EAH. Further, there was no significant association among average weekly sleep duration or EAH and fat mass. However, average weekday sleep was negatively associated, and average weekend sleep was positively associated, with EAH (ps < 0.02). Weekend “catch-up” sleep (the difference between weekend and weekday sleep) was positively associated with EAH (p < 0.01). Findings indicate that shorter weekday sleep and greater weekend “catch-up” sleep are associated with EAH, which may place youth at risk for the development of excess weight gain over time.

Sleep Duration and Risk of Obesity by Sex: Nine-Year Follow-Up of the Young Lives Study in Peru

Background: We aimed to evaluate if there is association between hours of sleep and the risk of obesity among children and whether this association differs by sex. Methods: A secondary data analysis, using information of the Young Lives study, was conducted. The outcome was obesity, based on the BMI for age z-score; the exposure was child's sleep duration (reported by parents) categorized using the National Sleep Foundation guidelines, and as a numerical variable. Baseline and three follow-ups information were used to evaluate association, reporting relative risks (RRs), and 95% confidence intervals (CIs), as well as coefficients and 95% CI. Results: Data from 1949 children, baseline mean age 4.3 (standard deviation: 0.3) and 962 (49.5%) females, were analyzed. Short sleep duration was present in 26.0% (95% CI: 24.0-28.0) at baseline. After 9.6 years of follow-up, the incidence of obesity was 0.83 (95% CI: 0.70-0.98) per 100 person-years at risk. In multivariable model (n = 1579), there was no association between short sleep duration and obesity in the whole sample (p = 0.13); but the risk of obesity was lower among girls (n = 816; RR = 0.45; 95% CI: 0.21-0.96; p = 0.03) compared with boys (n = 763; RR = 1.43; 95% CI: 0.95-2.14; p = 0.09). On the contrary, each additional hour of sleep was associated with an increase of boy's BMI mean (0.05; 95% CI: 0.02-0.08; p < 0.001), but not among girls (-0.02; 95% CI: -0.05 to 0.01; p = 0.11). Conclusions: Our results evidenced a lower risk of obesity due to short sleep duration in girls, but not in boys. Each additional hour of sleep was associated with an increase of BMI in boys, but not in girls. Strategies are needed to guarantee adequate sleep duration in Peruvian children.

Exploring Brazilian Immigrant Mothers' Beliefs, Attitudes, and Practices Related to Their Preschool-Age Children's Sleep and Bedtime Routines: A Qualitative Study Conducted in the United States

In the United States (US), racial/ethnic minority children, low-income children, and children of immigrant families are at increased risk of childhood obesity. Mounting evidence documents that sleep duration and sleep quality are important modifiable factors associated with increased risk of obesity among preschool-aged children. The number of Brazilian immigrants in the US is increasing, yet no existing research, to our knowledge, has examined factors affecting sleep and bedtime routines of children of Brazilian immigrant families. Therefore, the purpose of this qualitative study was to explore Brazilian immigrant mothers' beliefs, attitudes, and practices related to sleep and bedtime routines among preschool-aged children. Seven focus group discussions (FGDs) were conducted with 37 Brazilian immigrant mothers of preschool-age children living in the US. The audio-recordings of the FGDs were transcribed verbatim in Portuguese without identifiers and analyzed using thematic analyses. Mothers also completed a brief questionnaire assessing socio-demographic and acculturation. Analyses revealed that most mothers were aware of the importance of sleep and sleep duration for their children's healthy growth and development. Mothers also spoke of children needing consistent bedtime routines. Nevertheless, many mothers reported inconsistent and suboptimal bedtime routines (e.g., lack of predictable and orderly bedtime activities such as bath, reading, etc. and use of electronics in bed). These suboptimal routines appeared to be influenced by day-to-day social contextual and environmental factors that are part of Brazilian immigrant families' lives such as parents' work schedule, living with extended family, living in multi-family housing, neighborhood noise, etc. Analyses identified several modifiable parenting practices related to young children's sleep and bedtime routines (e.g., irregular bedtime, late bedtime, inconsistent bedtime routines, use of electronics in bed, etc.) that can be addressed in parenting- and family-based obesity prevention interventions. Interventions should consider the social context of the home/family (e.g., parents' work schedules) and the environment (e.g., multi-family housing; neighborhood noise, etc.) faced by Brazilian immigrant families when developing health promotion messages and parenting interventions tailored to this ethnic group.

25-Hydroxyvitamin D Status and Its Association with Sleep Duration in Chinese Schoolchildren

OBJECTIVE

To examine the association between 25-Hydroxyvitamin D (25(OH)D) levels and sleep duration among Chinese adolescents.

SUBJECTS AND METHODS

A school-based cross-sectional study was conducted among Chinese adolescents in 2017. Data on a total of 800 adolescents aged 8⁻14 years was used for this study. Anthropometric measurements such as height and weight were measured by trained research staff. Serum 25(OH)D and lipids were measured in the laboratory. Sleep habits and other health-related behaviors were tested by questionnaire.

RESULTS

25(OH)D levels were significantly positively correlated with sleep duration (r = 0.11, p < 0.05). In multivariate logistic regression analyses, insufficiency/deficiency of vitamin D (25(OH)D ≤ 20 ng/mL) was significantly associated with increased probability of short sleep (AOR = 1.67, 95% CI = 1.14⁻2.43).

CONCLUSIONS

Low 25(OH)D levels were independently associated with the risk of insufficient sleep in Chinese adolescents.

Sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades

We aimed to examine sleep patterns and their association with depression and behavior problems among Chinese adolescents in different grades. A cross-sectional study was conducted in 10 cities of mainland China. A total of 8,998 Chinese adolescents (49.3% males) aged 9-20 years completed a self-administered questionnaire that included questions on sleep patterns, depressive symptoms, behavior problems, and demographic characteristics. The percentage of adolescents who slept less than 7 hr on weekdays increased with grade, while the percentage of adolescents who slept less than 7 hr on weekends remained the same. The gap in sleep length between weekdays and weekends increased from 0.6 hr in grade 5 to 2.3 hr in Grade 12. The regression analysis showed that poor sleep habits were linked to greater emotional and behavioral problems. The associations of sleep length with those problems differed by symptom and grade. Sleeping less related to depression in all grades. More behavior problems were observed in primary school students who had less sleep and in senior high school students who had more sleep than their peers. The preference for going to bed late stably related to both adolescent depression and behavior problems in all grades, although it posed a greater risk for students in higher grades.

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.

Historical neighborhood poverty trajectories and child sleep

OBJECTIVES

To determine whether historical neighborhood poverty measures are associated with mothers' reports of their children's sleep duration and to compare results from historical neighborhood poverty measures to contemporaneous measures of neighborhood poverty.

DESIGN

The Geographic Research on Wellbeing (GROW) study is a follow-up survey of mothers who gave birth between 2003 and 2007. GROW mothers assessed their own and their children's health and health behaviors 5-10 years later (2012-2013).

SETTING

Urban Californian counties.

PARTICIPANTS

GROW respondents.

MEASUREMENTS

We categorized children's sleep as adequate or inadequate using clinical age-specific guidelines and based on mothers' reports of their child's sleep duration. We conducted a latent class analysis to identify historical poverty classes for all California census tracts using data from 1970 to 2005-2009, and we categorized current neighborhood poverty based on data from 2005 to 2009 only. We then assigned children to different neighborhood exposure classes based on their neighborhood of residence at birth and follow-up.

RESULTS

Logistic models indicated that net of controls for demographics, child behavior and health characteristics, mother characteristics, and household socioeconomic status, children who grew up in historically low (OR: 0.64, 95% confidence interval=0.45-0.92) or historically moderate poverty classes (OR: 0.68, 95% confidence interval=0.48-0.98) had lower odds of inadequate sleep duration compared with children who grew up in historically high poverty. We show that the historical specification of neighborhood poverty remained significant despite controls, whereas contemporaneous measures of neighborhood poverty did not.

CONCLUSIONS

Our findings indicate strong associations between historical neighborhood poverty and child sleep duration.

Sleep disorders in obese children are not limited to obstructive sleep apnoea syndrome

AIM

This study was to characterise respiratory and nonrespiratory sleep disorders in obese children and evaluate the diagnostic and therapeutic impact of a specific sleep consultation.

METHODS

A descriptive study was conducted in obese French children who received multidisciplinary care management from the hospital centre for paediatric obesity in Bordeaux. This followed a specific sleep consultation between 2007 and 2015, because their paediatrician had identified symptoms suggestive of sleep disorders.

RESULTS

The sleep specialist confirmed the presence of a sleep disorder in 98.4% of the 128 obese children, with a mean age of 12.1 ± 3.2 years. These included respiratory sleep disorders, hypersomnolence, insomnia and circadian rhythm sleep-wake disorders. Polysomnography revealed that 46.1% had respiratory sleep disorders and 24.2% had obstructive sleep apnoea syndrome (OSAS). Just under half (47.6%) were referred to an otorhinolaryngologist for sleep care management, 30.5% were referred to an orthodontist, 17.9% had melatonin treatment and 13.3% received continuous positive airway pressure ventilation.

CONCLUSION

Sleep disorders in obese children were not limited to respiratory sleep disorders including OSAS. A systematic specific consultation with a sleep specialist is essential for the diagnosis and care of such children and would be beneficial when treating paediatric obesity.

Overweight in youth and sleep quality: is there a link?

OBJECTIVE

Overweight seems to be related to a higher prevalence of sleep disturbances. Decreased sleep duration and altered sleep quality are risk factors for obesity. Our aim was to compare the sleep pattern of overweight children with that of a matched control group and assess the relationship between sleep quality and obesity.

MATERIALS AND METHODS

Retrospective cohort study comparing 41 overweight children with a normal-weight control group, both submitted to polysomnography. The samples were matched for age, sex, and apnea-hypopnea index. Body mass index (BMI) z-scores were calculated using World Health Organization (WHO) growth charts. Insulin resistance in the study group was determined using the homeostatic model assessment for insulin resistance (HOMA-IR). Sleep patterns were compared. The statistical analysis was performed using SPSS® version 21.

RESULTS

The mean age (± standard deviation) of the population was 10 ± 3.4 years (min. 5 years; max. 17 years). Fifty-six percent of the participants in both groups were girls. N3% was lower in the study group (18.95 ± 6.18%) compared with the control group (21.61 ± 7.39%; t (40) = 2.156, p = 0.037). We found a correlation in the study group between HOMA-IR and N3% (Rs = -0.434, p = 0.008).

CONCLUSION

The present study suggests a link between overweight/obesity and altered sleep quality due to compromised non-rapid eye movement sleep, an indirect marker of sleep quality. There was also a link between slow-wave sleep duration and insulin resistance. We must find a strategy to provide adequate slow-wave sleep duration to reduce the obesity epidemic at young ages. Further research is needed.

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.

Systematic review of the relationships between sleep duration and health indicators in school-aged children and youth

The objective of this systematic review was to examine the relationships between objectively and subjectively measured sleep duration and various health indicators in children and youth aged 5-17 years. Online databases were searched in January 2015 with no date or study design limits. Included studies were peer-reviewed and met the a priori-determined population (apparently healthy children and youth aged 5-17 years), intervention/exposure/comparator (various sleep durations), and outcome (adiposity, emotional regulation, cognition/academic achievement, quality of life/well-being, harms/injuries, and cardiometabolic biomarkers) criteria. Because of high levels of heterogeneity across studies, narrative syntheses were employed. A total of 141 articles (110 unique samples), including 592 215 unique participants from 40 different countries, met inclusion criteria. Overall, longer sleep duration was associated with lower adiposity indicators, better emotional regulation, better academic achievement, and better quality of life/well-being. The evidence was mixed and/or limited for the association between sleep duration and cognition, harms/injuries, and cardiometabolic biomarkers. The quality of evidence ranged from very low to high across study designs and health indicators. In conclusion, we confirmed previous investigations showing that shorter sleep duration is associated with adverse physical and mental health outcomes. However, the available evidence relies heavily on cross-sectional studies using self-reported sleep. To better inform contemporary sleep recommendations, there is a need for sleep restriction/extension interventions that examine the changes in different outcome measures against various amounts of objectively measured sleep to have a better sense of dose-response relationships.

Inadequate Sleep as a Mediating Variable between Exposure to Interparental Violence and Depression Severity in Adolescents

Exposure to violence, including interparental and peer dating violence, is a public health concern associated with negative outcomes, including depression. However, little is known about mechanisms by which exposure to violence influences depressive symptoms. One factor that may help explain this association is problematic sleep. This study sought to determine whether short sleep duration mediates the relationship between exposure to violence (interparental and peer dating violence) and depressive symptoms. Structural equation modeling was used to examine the mediating role of short sleep duration from a 3-year longitudinal study of 1,042 high school students. Results demonstrated interparental violence was negatively related to sleep duration (friends dating violence was not), and sleep duration negatively associated with depressive symptoms. Adolescents exposed to violence between their parents obtained less sleep on school nights. In turn, they reported more depressive symptoms. Short sleep duration mediated the relationship between exposure to interparental violence and depression severity.

Sleep Duration Trajectories and Body Composition in Adolescents: Prospective Birth Cohort Study

We aimed to estimate the association between sleep duration trajectories and body composition in adolescents. We used data from participants of the 1993 Pelotas (Brazil) Birth Cohort Study who were later followed up at age 18 years (response rate of 81.3%). At the time, 3974 adolescents had complete data on body composition, which was assessed by air displacement plethysmography. Sleep duration was self-reported by participants at ages 11 and 18 years. Analyses were sex-stratified. The mean sleep duration at 11 years was 9.7 (SD 1.4) and 8.4 (SD 1.9) at 18 years. Sleep duration was dichotomized as inadequate (<8 hours/day) or adequate (≥8 hours/day). Mean body mass, fat mass, and fat-free mass indices at 18 years were 23.4 kg/m² (SD 4.5), 6.1 kg/m² (SD 3.9) and 17.3 kg/m² (SD 2.5), respectively. Girls who reported inadequate sleep duration at 11 years of age, but adequate sleep duration at 18, on average experienced an increase in body mass index (β = 0.39 z-scores; 95% CI 0.13, 0.65), fat mass index (β = 0.30 z-scores; 95% CI 0.07, 0.53), and fat-free mass index (β = 0.24 z-scores; 95% CI 0.08, 0.39) compared to those who had adequate sleep duration at both time points. The results suggest that changes in sleep duration across adolescence may impact body composition in later adolescence and that this may differ by sex.

Associations between Sleep Duration and Overweight/Obesity: Results from 66,817 Chinese Adolescents

The findings about the shapes of associations between sleep duration and overweight/obesity in adolescents were largely inconsistent in the existing literature. We examined the functional forms of the associations between sleep duration and overweight/obesity in 66,817 Chinese adolescents by modelling sleep duration categorically and continuously. The adjusted ORs (95% CI) of overweight (with 7.0–8.9 h of sleep being considered the reference group) for subjects reporting <5.0 hours, 5.0–6.9 hours and ≥9.0 hours of sleep were 1.26 (1.05–1.51), 1.06 (1.00–1.11) and 1.27 (1.14–1.42), respectively. The adjusted ORs (95% CI) of obesity (with 7.0–8.9 h of daily sleep being considered as the reference group) for adolescents reporting <5.0 hours, 5.0–6.9 hours and ≥9.0 hours of sleep were 1.24 (0.97–1.57), 0.94 (0.87–1.01) and 1.42 (1.24–1.63), respectively. Continuous splines regressions support non-linear U shape associations between sleep duration and overweight/obesity, with the bottom at around 7.0–8.0 hours sleep (overweight: likelihood ratio = 32.7 p < 0.01; obesity: likelihood ratio = 40.4 p < 0.01). U-shape associations were found between sleep duration and overweight/obesity in Chinese adolescents and an optimal sleep duration of 7.0–8.0 hours sleep may prevent overweight/obesity.

Habitual Sleep Duration and Risk of Childhood Obesity: Systematic Review and Dose-response Meta-analysis of Prospective Cohort Studies

A meta-analysis of cross-sectional studies found that shorter-time sleep was correlated with increased risk of obesity in children. However, findings from prospective cohort studies were inconsistent. PubMed and other data resources were searched through May 2015. Twenty-five eligible studies were identified including 56,584 children and adolescents with an average 3.4-year follow-up. Compared with children having the longest sleep duration (~12.2 hours), kids with the shortest sleep duration (~10.0 hours) were 76% more likely to be overweight/obese (pooled odds ratio [OR]: 1.76; 95% confidence interval [CI]: 1.39, 2.23); and had relatively larger annual BMI gain (pooled β coefficient: 0.13; 95% CI: 0.01, 0.25 kg/m²). With every 1 hour/day increment in sleep duration, the risk of overweight/obesity was reduced by 21% (OR: 0.79; 95% CI: 0.70, 0.89); and the annual BMI gain declined by 0.05 kg/m² (β = −0.05; 95% CI: −0.09, −0.01). The observed associations were not appreciably modified by region, baseline age or the length of follow-up. Accumulated literature indicates a modest inverse association between sleep duration and the risk of childhood overweight/obesity. Further research is needed to determine the age and gender specified optimal hours of sleep and ideal sleep pattern with respect to obesity prevention in children.

Interactive vs passive screen time and nighttime sleep duration among school-aged children

BACKGROUND

Insufficient sleep among school-aged children is a growing concern, as numerous studies have shown that chronic short sleep duration increases the risk of poor academic performance and specific adverse health outcomes. We examined the association between weekday nighttime sleep duration and 3 types of screen exposure: television, computer use, and video gaming.

METHODS

We used age 9 data from an ethnically diverse national birth cohort study, the Fragile Families and Child Wellbeing Study, to assess the association between screen time and sleep duration among 9-year-olds, using screen time data reported by both the child (n = 3269) and by the child's primary caregiver (n= 2770).

RESULTS

Within the child-reported models, children who watched more than 2 hours of television per day had shorter sleep duration by approximately 11 minutes per night compared to those who watched less than 2 hours of television (β = -0.18; P < .001). Using the caregiver-reported models, both television and computer use were associated with reduced sleep duration. For both child- and parent-reported screen time measures, we did not find statistically significant differences in effect size across various types of screen time.

CONCLUSIONS

Screen time from televisions and computers is associated with reduced sleep duration among 9-year-olds, using 2 sources of estimates of screen time exposure (child and parent reports). No specific type or use of screen time resulted in significantly shorter sleep duration than another, suggesting that caution should be advised against excessive use of all screens.

Longitudinal differences in sleep duration in Hispanic and Caucasian children

BACKGROUND AND AIM

Short sleep duration is associated with significant negative consequences, including poor school performance, behavioral problems, obesity, and hypertension. There is prior evidence that there are disparities in sleep duration related to ethnicity; however, there are no specific data on Hispanic children. We aimed to test the hypothesis that there are ethnic differences in parent-reported sleep duration in a community-based cohort of Hispanic and Caucasian children.

METHODS

We examined the parent-reported sleep patterns of a community-based prospective cohort (Tucson Children's Assessment of Sleep Apnea study [TuCASA]) involving 338 Hispanic and Caucasian children at two time points approximately five years apart.

RESULTS

In the initial phase of the TuCASA study with a cohort median age of 8.8 years (interquartile range (IQR), 7.6-10.1 years), parent-reported sleep duration during weekdays was shorter in Hispanic (median, 9.5 h; IQR, 9.0, 10.0 years) than in Caucasian children (10 h; IQR, 9.5, 10.0 h; p < 0.0001); however, this difference was not seen 5 years later when the cohort was older (median age, 13.3 years; IQR, 11.9-14.6 years; p = 0.43). In addition, Hispanic children had a significantly later bedtime at both time points (p < 0.02). In the initial phase, parent-reported sleep duration during weekends tended to be shorter in Hispanic than in Caucasian children (p = 0.06).

CONCLUSIONS

Short sleep duration in Hispanic children may contribute to health disparities. Our research suggests that in Hispanic children, behavioral interventions toward improving sleep duration accomplished by earlier bedtimes or delayed school start times and mechanistic studies to unravel any inherent tendency toward a delayed sleep phase are needed.

Sleep characteristics and cardiovascular risk in children and adolescents: an enumerative review

Cardiovascular risk factors develop in childhood and adolescence. This enumerative review addresses whether sleep characteristics, including sleep duration, continuity, quality, and daytime sleepiness, are associated with cardiovascular risk factors in young people. Thirty-nine studies were identified, which examined the following risk factors: metabolic syndrome, glucose and insulin, lipids, blood pressure, and cardiovascular responses to psychological stressors. Due to the availability of other reviews, 16 longitudinal studies of obesity published in 2011 and later were also included in this report. Excluded from the review were studies of participants with suspected or diagnosed sleep disorders and reports from sleep deprivation experiments. Combining studies, evidence was strongest for obesity, followed by glucose, insulin, blood pressure (especially ambulatory blood pressure), and parasympathetic responses to psychological stressors. There was little evidence for metabolic syndrome cluster, lipids, and blood pressure responses to psychological stressors. The more positive associations were obtained for studies that incorporated objective measures of sleep and that included adolescents. The foundational evidence is almost entirely cross-sectional, except for work on obesity. In summary, available evidence suggests that the associations between sleep characteristics and cardiovascular risk vary by risk factor. It is time to conduct studies to determine antecedent and consequent relationships, and to expand risk factors to include markers of inflammation.

Effects of a workplace intervention on sleep in employees' children

PURPOSE

The implications of sleep patterns for adolescent health are well established, but we know less about larger contextual influences on youth sleep. We focused on parents' workplace experiences as extrafamilial forces that may affect youth sleep.

METHODS

In a group-randomized trial focused on employee work groups in the information technology division of a Fortune 500 company, we tested whether a workplace intervention improved sleep latency, duration, night-to-night variability in duration, and quality of sleep of employees' offspring, aged 9-17 years. The intervention was aimed at promoting employees' schedule control and supervisor support for personal and family life to decrease employees' work-family conflict and thereby promote the health of employees, their families, and the work organization. Analyses focused on 93 parent-adolescent dyads (57 dyads in the intervention and 46 in the comparison group) that completed baseline and 12-month follow-up home interviews and a series of telephone diary interviews that were conducted on eight consecutive evenings at each wave.

RESULTS

Intent-to-treat analyses of the diary interview data revealed main effects of the intervention on youth's sleep latency, night-to-night variability in sleep duration, and sleep quality, but not sleep duration.

CONCLUSIONS

The intervention focused on parents' work conditions, not on their parenting or parent-child relationships, attesting to the role of larger contextual influences on youth sleep and the importance of parents' work experiences in the health of their children.

Prospective associations between sedentary time, sleep duration and adiposity in adolescents

•

We examined sedentary time and sleep length relative to changes in youth adiposity.

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Sedentary time was not associated with change in adiposity in either gender.

•

Sleep duration was significantly inversely associated with adiposity gain in boys.

•

The association for sleep in boys was attenuated by physical activity and depression.

Objective

The objective of this study was to investigate whether objectively measured sedentary time and sleep duration are associated with changes in adiposity from mid- to late adolescence.

Methods

Students (n = 504, 42% boys) were recruited from schools in Cambridgeshire, UK. At baseline (mean age 15.0 ± 0.3 years), sedentary time was objectively measured by ≥3 days of combined heart rate and movement sensing. Concurrently, sleep duration was measured by combined sensing in conjunction with self-reported bed times. Fat mass index (FMI; kg/m²) was estimated at baseline and follow-up (17.5 ± 0.3 years) by anthropometry and bioelectrical impedance. FMI change (ΔFMI) was calculated by subtracting the baseline from follow-up values. Linear regression models adjusted for basic demographics, moderate-to-vigorous physical activity (MVPA), and depressive symptoms were used to investigate associations of sedentary time and sleep duration (mutually adjusted for one another) with ΔFMI.

Results

FMI increased by 0.5 and 0.6 kg/m² in boys and girls, respectively, but there was no association between sedentary time and ΔFMI in either gender (p ≥ 0.087), and no association between sleep duration and ΔFMI in girls (p ≥ 0.61). In boys, each additional hour of baseline sleep significantly reduced the ΔFMI by 0.13 kg/m² (p = 0.049), but there was little evidence for this association after adjusting for MVPA and depressive symptoms (p = 0.15).

Conclusions

Sedentary time may not determine changes in adiposity from mid- to late adolescence, nor may sleep duration in girls. However, sleep length may be inversely associated with adiposity gain in boys, depending on whether the relationship is confounded or mediated by MVPA and depression.