Exploring the Relationship Between Age at Nap Cessation and Social-Emotional Functioning in Children.

OBJECTIVE: The objective of this study was to examine variations in age at nap cessation and identify whether there is an association with social-emotional functioning (SEF) as measured by internalizing/externalizing behavior, child temperament, and social skills in a sample of early childhood education and care-attending children. METHODS: The sample comprised 1117 children from the Australian Effectiveness Early Educational Experiences for Children longitudinal early childhood study. We used children's age at nap cessation as retrospectively recalled by caregivers in 2011 or 2013 when children were between ages 2 and 7 years. Each child's SEF was reported by a caregiver using the Strengths and Difficulties Questionnaire, the Short Temperament Scale for Children, and the Social Skills Inventory Scale. Associations between children's age of nap cessation and SEF were tested using linear regressions. RESULTS: The children's age at nap cessation ranged from 6 months to 6 years. For each additional year of napping, children's total , conduct , externalizing , and peer behavior problems decreased by 0.39 (95% confidence interval [CI], -0.70 to -0.09), 0.11 (95% CI, -0.21 to -0.01), 0.11 (95% CI, -0.51 to -0.06), and 0.11 (95% CI, -0.20 to -0.02) units on the Strengths and Difficulties Questionnaire scale, respectively. No further significant associations were found. CONCLUSION: This is the first study reporting the age range of nap cessation and its associations with social-emotional functioning. Our findings demonstrate earlier cessation ages in Australian children attending Early Childhood Education and Care programs than previously reported and a small association with externalizing and peer problems.

Reducing crash risk for young drivers: Protocol for a pragmatic randomised controlled trial to improve young driver sleep.

Background: Road trauma is a leading cause of death and disability for young Australians (15-24 years). Young adults are overrepresented in crashes due to sleepiness, with two-thirds of their fatal crashes attributed to sleepy driving. This trial aims to examine the effectiveness of a sleep extension and education program for improved road safety in young adults. Methods: Young adults aged 18-24 years (n = 210) will be recruited for a pragmatic randomised controlled trial employing a placebo-controlled, parallel-groups design. The intervention group will undergo sleep extension and receive education on sleep, whereas the placebo control group will be provided with information about diet and nutrition. The primary outcomes of habitual sleep and on-road driving performance will be assessed via actigraphy and in-vehicle accelerometery. A range of secondary outcomes including driving behaviours (driving simulator), sleep (diaries and questionnaire) and socio-emotional measures will be assessed. Discussion: Sleep is a modifiable factor that may reduce the risk of sleepiness-related crashes. Modifying sleep behaviour could potentially help to reduce the risk of young driver sleepiness-related crashes. This randomised control trial will objectively assess the efficacy of implementing sleep behaviour manipulation and education on reducing crash risk in young adult drivers.

Data from four consecutive cohorts of students in Australia (2019-2022) show the impact of the COVID-19 pandemic on domestic and international university students' mental health.

INTRODUCTION: COVID-19 and related travel and social restrictions caused significant stress for university students in Australia and globally. Learning quickly moved online and many students (particularly international students) were separated from social and economic support. This study examined the impact of the pandemic from pre-pandemic (2019) to the COVID-19 Omicron wave (2022) on domestic and international students' mental health. METHODS: Participants were 1540 students (72% females, 28% international) in four first-year cohorts (2019, 2020, 2021, 2022). We screened for mental health concerns (% positive) and symptom scores for depression, anxiety and somatic distress using the PsyCheck, and general wellbeing using the Warwick-Edinburgh Mental Well-being scale. RESULTS: From pre-COVID (2019) to the first wave of COVID-19 (2020), the proportion of students screening positive for mental health problems rose in both domestic students (66-76%) and international students (46-67%). Depression symptoms and wellbeing were worse in 2020 than in 2019, 2021 and 2022. Anxiety symptoms increased from 2019 to 2020 and continued to rise in 2021 and 2022. Somatic symptoms did not show an effect of cohort. Contrary to expectations, domestic students reported higher distress and lower wellbeing than international students across cohorts. CONCLUSION: The pandemic was associated with a marked increase in psychological distress in first-year university students, not all of which settled with the easing of restrictions. Post-pandemic recovery in the Australian university sector must include university-wide access to mental health information and support for incoming students.

Perceived Neighborhood Characteristics and Sleep in Australian Adults.

BACKGROUND: Poor sleep can contribute to poorer health and socioemotional outcomes. Sleep health can be influenced by a range of individual and other socioecological factors. Perceptions of neighborhood physical and social characteristics reflect broader social-level factors that may influence sleep, which have not been well studied in the Australian context. This study examined the association between perceived neighborhood characteristics and sleep in a large sample of Australians. METHODS: Data were from 9,792 people aged 16 years or older, from Waves 16 and 17 of the nationally representative Household, Income and Labour Dynamics in Australia Survey. Associations between perceived neighborhood characteristics (neighborly interaction and support, environmental noise, physical condition, and insecurity) and self-reported sleep duration, sleep disturbance, and napping were examined using multiple logistic regression models. RESULTS: "Neighborhood interaction and support" and "neighborhood physical condition" were not significantly associated with any sleep outcomes after adjusting for relevant covariates. However, "environmental noise" and "neighborhood insecurity" remained significantly associated with sleep duration and sleep disturbance. None of the neighborhood characteristics were associated with napping. Furthermore, associations did not significantly vary by gender. CONCLUSIONS: This study highlights the potential benefit of public health policies to address noise and safety in neighborhoods to improve sleep.

Sleep mediates the relationship between precarious employment and mental health.

Background: Current evidence suggests that precarious employment is a risk factor for poor mental health. Although the mechanisms underpinning this relationship are unclear, poor sleep has been proposed to have a role in this relationship. This study explored the mediating effects of poor sleep quality and duration on the relationship between precarious employment and mental health. Methods: Data were obtained from wave 17 of the Household, Income and Labour Dynamics in Australia survey. A novel precarious employment score (PES) was developed using exploratory and confirmatory factor analyses (CFA) in 8127 workers (4195 female, aged 18-65). Structural equation modelling (SEM) was used to evaluate the mediating effect of sleep quality and duration on the relationship between precarious employment and mental health (SF-36 mental health subscale). Results: The PES identified 650 workers with a high level of precariousness, 2417 with a moderate level of precariousness, and 5060 workers with a low level of precariousness out of 8127 in total. There was a significant direct association between precarious employment and mental health; with higher precarity increasing the likelihood of poor mental health. The SEM results revealed that sleep quality partially mediated the association between precarious employment and mental health (Coefficient = 0.025, 95 % CI [0.015, 0.034], P ≤ 0.001). However, a mediation effect was not found for sleep duration. Conclusion: Encouraging precarious employees to improve sleep quality may mitigate the adverse effects of precarious work on their mental health. Further objective measurement of sleep duration warrants a more accurate insight into this mediating effect in this group.

Objective Measurement of Posture and Movement in Young Children Using Wearable Sensors and Customised Mathematical Approaches: A Systematic Review.

Given the importance of young children's postures and movements to health and development, robust objective measures are required to provide high-quality evidence. This study aimed to systematically review the available evidence for objective measurement of young (0-5 years) children's posture and movement using machine learning and other algorithm methods on accelerometer data. From 1663 papers, a total of 20 papers reporting on 18 studies met the inclusion criteria. Papers were quality-assessed and data extracted and synthesised on sample, postures and movements identified, sensors used, model development, and accuracy. A common limitation of studies was a poor description of their sample data, yet over half scored adequate/good on their overall study design quality assessment. There was great diversity in all aspects examined, with evidence of increasing sophistication in approaches used over time. Model accuracy varied greatly, but for a range of postures and movements, models developed on a reasonable-sized (n > 25) sample were able to achieve an accuracy of >80%. Issues related to model development are discussed and implications for future research outlined. The current evidence suggests the rapidly developing field of machine learning has clear potential to enable the collection of high-quality evidence on the postures and movements of young children.

Precarious employment and associated health and social consequences; a systematic review.

OBJECTIVE: This systematic review aims to identify, evaluate, and summarise the consequences of precarious employment. METHODS: We included studies published within the last ten years (Jan 2011-July 2021) that employed at least two of three key dimensions of precarious employment: employment insecurity, income inadequacy, and lack of rights and protection. RESULTS: Of the 4,947 initially identified studies, only five studies met our eligibility criteria. These five studies were of moderate quality as assessed by the Newcastle-Ottawa Scale. Our review found that the current literature predominantly defines precarity based on the single criterion of employment insecurity. Our review identified evidence for the negative consequences of precarious employment, including poorer workplace wellbeing, general health, mental health, and emotional wellbeing. The findings indicated an increase in the magnitude of these adverse outcomes with a higher degree of job precariousness. CONCLUSIONS: The rise of employment precariousness will likely continue to be a major issue in the coming years. More research is needed to inform effective policies and practices using a consensus definition of precarious employment. IMPLICATIONS FOR PUBLIC HEALTH: The presence of adverse effects of precarious employment suggests workplace initiatives are essential to mitigate the negative consequences of precarity.

Interventions to increase sleep duration in young people: A systematic review.

This systematic review explored the outcomes of current interventions to increase sleep duration in healthy young people (14-25 years). Nine databases were systematically searched, and 26 studies were included in this review. Quality assessment of the included studies was evaluated using two tools: the Newcastle-Ottawa scale, and Cochrane Risk of Bias. The interventions incorporated a range of strategies including behavioral (46.2%), educational (26.9%), a combination of behavioral and educational (15.4%), and other strategies such as physical therapy (11.5%). The findings indicate that behavioral and combination interventions were consistently effective in increasing sleep duration in healthy young people. Educational interventions alone were less effective at increasing young people's sleep duration. Of all the included studies, only one randomized control trial but none of the non-randomized trials were rated as good quality. Our findings suggest a combination of strategies with an emphasis on personalization of intervention could possibly maximize the chances of success at improving sleep duration in healthy young people. More high-quality studies with long-term assessments (≥ 6 months) should be conducted to test the efficacy and durability of interventions to increase sleep duration in young people, as well as the clinical implications to mental and physical health.

Prevalence and predictors of sleep problems in women following a cancer diagnosis: results from the women's wellness after cancer program.

PURPOSE: Using a discrete dataset from the Women's Wellness after Cancer Program (WWACP), we examine the prevalence and predictors of self-reported sleep problems in women previously treated for cancer. METHODS: Participants were 351 women (Mage = 53.2, SD = 8.8) from the WWACP who had completed surgery, chemotherapy and/or radiotherapy for breast, gynaecological or blood cancers within the previous 24 months. Sleep problems were measured using the Pittsburgh Sleep Quality Index (PSQI). Baseline data (i.e. prior to intervention randomisation) were analysed. RESULTS: Most women (59%) reported clinically significant sleep disturbance (PSQI > 5), 40% reported insufficient sleep duration (< 7 h), 38% self-reported poor sleep quality and 28% reported poor habitual sleep efficiency (sleep efficiency < 75%). Fewer psychological and vasomotor climacteric symptoms, age < 45 years and having a partner were associated with reduced odds (AOR < 1) of sleep problems. Higher levels of pain-related disability, and an intermediate compared to 'high' level of education, were associated with increased odds (AOR > 1) of sleep problems. CONCLUSIONS: These findings confirm previous studies that have found a high prevalence of sleep problems in women previously treated for cancer. A range of sociodemographic, climacteric and pain-related factors were associated with sleep problems in this study. IMPLICATIONS FOR CANCER SURVIVORS: Targeted interventions to improve sleep quality after cancer treatment should be explored in this population. Predictors identified in this study could inform intervention targeting and development.

Geographical variations in the prevalence of traditional and cyberbullying and its additive role in psychological and somatic health complaints among adolescents in 38 European countries.

OBJECTIVES: To explore geographical variations in the prevalence of traditional and cyberbullying and their individual and additive role on psychological and somatic health issues of adolescents. METHODS: We used cross-sectional data from 188,003 adolescents (50.9% females; mean age 13.6 years) from the nationally representative Health Behaviour in School-aged Children 2014 survey in 38 European countries. Multivariable linear regression analyses were conducted to explore the role of bullying on health outcomes whilst meta-analyses were conducted to generate pooled regression coefficients. RESULTS: Overall, the prevalence of traditional bullying was 26.9%, ranges from 8.8% in Armenia to 49.7% in Latvia, and cyberbullying was 15.8%, ranges from 5.8% in Greece to 38.3% in Greenland. 1 in 10 (8.4%) adolescents reported experiencing both forms of bullying, with the prevalence ranging from 2.5% (Greece) to 21.0% (Greenland). Meta-analytic estimates suggest a significant role of both traditional and cyberbullying in poor somatic and psychological health issues. The additive effect of both forms of bullying was more prominent on psychological health issues (ß 0.70, 95% CI 0.66-0.74) than on somatic health issues (ß 0.50, 95% CI 0.47-0.53). These associations varied across countries. CONCLUSION: The prevalence of traditional and cyberbullying varied significantly across European countries while their individual and additive links with an increased risk of poor psychological and somatic health issues remain common in majority countries. To ensure both forms of bullying are prevented, a multifaceted approach and particular attention to mental health issues in bullying victims are needed in countries with high prevalence of bullying.

Sleep and health-related quality of life in women following a cancer diagnosis: results from the Women's Wellness after Cancer Program in Australia.

PURPOSE: Sleep disturbance after cancer treatment could compromise recovery. This paper examined the associations between post-treatment sleep problems and health-related quality of life (HRQoL), and the effectiveness of an e-enabled lifestyle intervention on sleep outcomes. METHODS: The Women's Wellness after Cancer Program (WWACP) was examined in a single blinded, multi-centre randomised controlled trial. Data were collected from 351 women (Mage = 53.2, SD = 8.8; intervention n = 175, control group n = 176) who had completed surgery, chemotherapy and/or radiotherapy for breast, gynaecological or blood cancers within the previous 24 months. Participants completed the Pittsburgh Sleep Quality Index (PSQI) at baseline (prior to intervention randomisation), and at 12 and 24 weeks later. Sociodemographic information, menopausal symptoms (Greene Climacteric Scale) and HRQoL (36-Item Short Form Health Survey; SF-36) were also collected. Linear panel regression was used to examine the association between sleep variables and SF36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. A difference-in-difference regression model approach was used to examine the intervention effect on the sleep outcomes. RESULTS: After adjustment for potential confounders, the sleep variables (except sleep duration) significantly predicted physical, but not mental, HRQoL. There was no statistically significant effect of the intervention on sleep outcomes at 12 or 24 weeks. CONCLUSION: Women who have completed treatment for cancer experience sleep problems that are associated with decreased physical HRQoL. Improving sleep through targeted interventions should improve their physical HRQoL. Improved targeting of the sleep components of the WWACP should be explored.

Bright light alone or combined with caffeine improves sleepiness in chronically sleep-restricted young drivers.

BACKGROUND: Young drivers are over-involved in sleepiness-related crashes. The alerting effects of bright light offer a potential countermeasure for driver sleepiness, either replacing or in conjunction with current countermeasures such as the use of caffeine. METHODS: Thirty young (18-25) chronically sleep-restricted drivers drove in a simulator under randomized conditions of continuous bright light ('Light,' 500 nm, 230µw/cm2), caffeine ('Caffeine,' 100 mg caffeinated gum), or light and caffeine together ('Light + Caffeine'), after driving under a placebo condition ('Placebo,' decaffeinated gum, 555 nm light, 0.3 µW/cm2) on three consecutive days. Using mixed-effects linear models, the associations between these conditions and physiological outcomes (EEG alpha and theta power, heart rate, and beat-to-beat intervals), driving performance (lateral lane and steering-related outcomes and lateral acceleration), and subjective sleepiness was assessed. RESULTS: Relative to Placebo, all conditions improved driving performance outcomes (P < 0.0001), with effects of Light + Caffeine equal to Light but greater than Caffeine. Light + Caffeine reduced EEG alpha power more than Light or Caffeine (P < 0.0006), but ECG outcomes were generally worse under all conditions relative to Placebo. Subjective sleepiness improved under the Light + Caffeine condition only (P < 0.0001). CONCLUSIONS: Combining bright light and caffeine enhances their alerting effects on lateral lane variability and subjective sleepiness. A bright light could be a practical alternative to caffeine for sleepy drivers who avoid caffeine. The alerting effects of bright light could alleviate chronic community-level mild sleep restriction and provide on-road benefits to reduce severe injuries and fatal sleepiness-related crashes.

Geographical variations in the association between bullying victimization and sleep loss among adolescents: a population-based study of 91 countries.

OBJECTIVE: To examine geographical variations in the association between bullying victimization and sleep loss over worry among adolescents. METHODS: We used data from the Global School-based Student Health Survey conducted between 2003 and 2017 in 91 countries across the globe. Sleep loss was categorised as: none/minimum (reported never or rarely sleep loss), moderate (reported sometimes), and severe (reported most of the time or always). We obtained country-specific estimates from multiple multinomial logistic regression analyses and pooled estimates from meta-analyses. RESULTS: Of 282,036 adolescents 13-17 years of age, 28.1% (male: 25.4%, female: 31.0%) and 8.4% (male: 7.3%, female: 9.5%) of adolescents reported moderate and severe sleep loss respectively. Adolescents who frequently experienced bullying (≥3 per 30 days) reported higher prevalence of severe sleep loss. Meta-analyses showed that increased frequency of bullying victimization is associated with increased odds of sleep loss, with adolescents who experienced bullying for ≥3 days in the past 30 days were 1.65 and 2.65 times more likely than adolescents without being bullied to experience respectively moderate (OR 1.65, 95% CI: 1.59-1.72) and severe (OR 2.65, 95% CI: 2.52-2.79) sleep loss. Irrespective of sex, the association between bullying victimization and sleep loss was significant in all regions, income groups, and in all but a few countries. CONCLUSIONS: Increased frequency of bullying victimization is positively associated with increased sleep loss among adolescents. Appropriate policies and programmes to stop bullying at school could help downgrade the risk of sleep loss among adolescents.

Many naps, one nap, none: A systematic review and meta-analysis of napping patterns in children 0-12 years.

The onset of monophasic sleep, in which napping ceases and sleep consolidates into a single night period, is a key developmental milestone of childhood. Yet to date, there is little consensus regarding the timing of cessation of napping in children. The aim of the current study is to examine global evidence regarding napping patterns in childhood, and, through meta-analysis, describe patterns of napping cessation and duration observed in children aged 0-12 y. A systematic search of all published, original research articles reporting children's napping patterns, by age, was conducted. The quality of studies was assessed, and meta-analysis of eligible studies undertaken. Risk of bias and heterogeneity of measurement was high. Current evidence indicates that less than 2.5% of children cease napping prior to age 2, while 94% cease napping by age 5. The preschool period (3-5 y; 36-60 mo) represents a particularly dynamic period in napping cessation, with large variation in rates of napping across studies evidencing potential ecological effects. Future studies should focus on understanding of the underlying mechanisms explaining individual variations in napping patterns and the extent to which patterns of napping may represent a marker of child development.

How Well Do Children Understand the Vocabulary of Sleep?

BACKGROUND: Sleep surveys, such as the Pediatric Daytime Sleepiness Scale (PDSS), are used to determine a variety of concerns associated with sleep, including excessive daytime sleepiness (hypersomnolence), bedtime sleep behaviors, night awakenings, sleep duration, and sleep-disordered breathing. However, the literacy ability of the patient may not be adequate to ensure comprehension of questions and provision of accurate responses. OBJECTIVE: To assess children's understanding of the sleep-associated vocabulary included in the PDSS. METHODS: A cross-sectional, open-response survey was developed for use with students age 4 to 12 years. Prior to completing the instrument, each student was asked the meaning of six key sleep-related words used in the PDSS: drowsy, sleepy, alert, awakened, tired, and awake. The parents/caregivers were requested to record their child's definitions of these key words exactly as stated. Identification of words for "suitable" definitions was undertaken through consultation of three online dictionaries. This enabled the qualitative process associated with open-response surveys to be followed: identification of common themes, chunking of information, and criteria for coding responses. The final sample consisted of word definitions from 325 students (152 boys and 173 girls) from a school enrollment of 727 (45%). KEY RESULTS: A high percentage of children provided "suitable" responses for the words sleepy (84%) and tired (75%). The percentage of "suitable" responses for the words drowsy and awakened gradually increased across the age groups. The words alert and awake were challenging for the children to define, with the sleep-associated definition for alert only being provided by 31% of children overall and awake only being provided by 48% overall. In total, 57% of children were able to provide suitable definitions for at least four words. CONCLUSIONS: Our findings suggest that the results of many sleep surveys using these terms may not yield results that accurately reflect a child's actual state of daytime sleepiness and sleep/wake behaviors. Prior to administering a sleep survey, physicians need to clearly explain the meanings of sleep-associated words used in the survey and thus gain a more accurate reflection of a child's sleep and daytime behaviors. [HLRP: Health Literacy Research and Practice. 2019;3(1):e53-e69.]. PLAIN LANGUAGE SUMMARY: Sleep surveys are used to identify problems with sleep. Children with poor health literacy due to age may not understand the questions and may not provide adequate answers. Children's understanding of sleep-associated vocabulary was assessed using six words: drowsy, sleepy, alert, awakened, tired, and awake. Many of these words were found to be difficult for the children to define.

Correlates of naptime behaviors in preschool aged children.

Purpose: Major changes in the timing, duration, and function of sleep occur during childhood. These changes include the transition from habitual napping to infrequent napping. This transition is likely to reflect, at least in part, neurocognitive development. This study sought to identify factors that discriminate between four groups of children with different teacher-reported responses to naptime in childcare: those who nap (nappers), sometimes nap (transitioners), do not nap (resters), and neither nap, nor lie still (problem nappers). Methods: Standardized observations of sleep and sleep behaviors, daytime behaviors across a number of domains, and direct neurocognitive assessment of 158 preschool aged children (aged 49-72 months; 54% male) attending childcare centers in Queensland (QLD), Australia, were adopted as part of a large longitudinal study of early childhood, the Effective Early Education Experiences (E4Kids) study. Discriminant function analysis was used to examine how age, parent education, nighttime sleep duration, cognitive functioning, behavior problems, and temperament differentiated the four groups. Results: Three discriminant functions were identified and defined as maturation (strong loadings of nighttime sleep duration, cognitive function, and age), socioeconomic status (parental education), and behavioral problems (externalizing behavior, temperament, and internalizing behavior). These functions accounted for 62.9%, 32.6%, and 4.5% of the between-groups variance, respectively. Children defined as nappers (n=44) had significantly shorter duration of nighttime sleep, were younger, and had lower cognitive functioning scores than did other groups. Problem nappers, (n=25) were more likely to have parents with lower levels of education than did transitioners (n=41). Standard behavior and temperament measures did not significantly differentiate the groups. Conclusion: The findings support an interaction between cognitive development, sleep behaviors, and the individual needs and circumstances of children. Further research in this area could make a strong contribution to theory and practice in early childhood education, and a strong contribution to understanding of children's development.

Dynamics of corticospinal motor control during overground and treadmill walking in humans.

Increasing evidence suggests cortical involvement in the control of human gait. However, the nature of corticospinal interactions remains poorly understood. We performed time-frequency analysis of electrophysiological activity acquired during treadmill and overground walking in 22 healthy, young adults. Participants walked at their preferred speed (4.2, SD 0.4 km/h), which was matched across both gait conditions. Event-related power, corticomuscular coherence (CMC), and intertrial coherence (ITC) were assessed for EEG from bilateral sensorimotor cortices and EMG from the bilateral tibialis anterior (TA) muscles. Cortical power, CMC, and ITC at theta, alpha, beta, and gamma frequencies (4-45 Hz) increased during the double support phase of the gait cycle for both overground and treadmill walking. High beta (21-30 Hz) CMC and ITC of EMG was significantly increased during overground compared with treadmill walking, as well as EEG power in theta band (4-7 Hz). The phase spectra revealed positive time lags at alpha, beta, and gamma frequencies, indicating that the EEG response preceded the EMG response. The parallel increases in power, CMC, and ITC during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. The evoked responses are not consistent with the idea of synchronization of ongoing corticospinal oscillations but instead suggest coordinated cortical and spinal inputs during the double support phase. Frequency-band dependent differences in power, CMC, and ITC between overground and treadmill walking suggest differing neural control for the two gait modalities, emphasizing the task-dependent nature of neural processes during human walking. NEW & NOTEWORTHY We investigated cortical and spinal activity during overground and treadmill walking in healthy adults. Parallel increases in power, corticomuscular coherence, and intertrial coherence during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. These findings identify neurophysiological mechanisms that are important for understanding cortical control of human gait in health and disease.

Investigating the association between sleep parameters and the weight status of children: night sleep duration matters.

OBJECTIVES: To examine the associations between sleep parameters and weight status in a large sample of preschool children. DESIGN: Cross-sectional survey data from the Effective Early Educational Experiences for children (E4Kids) study were analyzed. PARTICIPANTS: 1111 children aged 3 to 6 years from Queensland and Victoria, Australia. MEASUREMENTS: General linear modeling, with adjustment for significant control variables, assessed the impact of night sleep duration, total sleep duration, napping frequency, sleep timing (onset, offset and midpoint), and severity of sleep problems on standardized body mass index (BMI z score). General linear modeling was conducted for the total sample and then separately by sex. RESULTS: For the total sample, there was a significant association between short sleep duration (≤10 hours) and increased BMI z score. No other sleep parameters were associated with BMI z score in this sample. Analyses by sex revealed that, among girls, there were no associations between any sleep parameter and BMI z score. However, among boys, short night sleep duration and napping frequency were both significantly associated with weight status even after adjustment for controls. CONCLUSION: Night sleep duration is a consistent independent predictor of body mass in young children. These results identify a complex relationship between sleep and body mass that implicates sex. Potential mechanisms that might explain sex differences warrant further investigation.