Patterns of perinatal polyunsaturated fatty acid status and associated dietary or candidate-genetic factors

Perinatal exposure to omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) can be characterized through biomarkers in maternal or cord blood, or breast milk. Objectives were to describe perinatal PUFA status combining multiple biofluids, and to investigate how it was influenced by dietary intake during pregnancy and maternal FADS and ELOVL gene polymorphisms. This study involved 1,901 mother-child pairs from the EDEN cohort, with PUFA levels measured in maternal and cord erythrocytes, and colostrum. Maternal dietary PUFA intake during the last trimester was derived from a food frequency questionnaire. Twelve single nucleotide polymorphisms in FADS and ELOVL genes were genotyped from maternal DNA. Principal component analysis incorporating PUFA levels from the three biofluids identified patterns of perinatal PUFA status. Spearman's correlations explored associations between patterns and PUFA dietary intake, and linear regression models examined pattern associations with FADS or ELOVL haplotypes. Five patterns were retained: "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs"; "Omega-6 LC-PUFAs"; "Colostrum LC-PUFAs"; "Omega-6 precursor (LA) and DGLA"; "Omega-6 precursor and colostrum ALA". Maternal omega-3 LC-PUFA intakes were correlated with "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs" (r(DHA) = 0.33) and "Omega-6 LC-PUFAs" (r(DHA) = -0.19) patterns. Strong associations were found between FADS haplotypes and PUFA patterns except for "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs". Lack of genetic association with the "High omega-3 LC-PUFAs, low omega-6 LC-PUFAs" pattern, highly correlated with maternal omega-3 LC-PUFA intake, emphasizes the importance of adequate omega-3 LC-PUFA intake during pregnancy and lactation. This study offers a more comprehensive assessment of perinatal PUFA status and its determinants.

Effectiveness of an intervention program on physical activity in children with narcolepsy type 1

OBJECTIVES

Physical activity (PA) is recommended as part of the management of narcolepsy type 1 (NT1). This study aimed at 1) characterizing PA in children and adolescents treated for NT1 using objective and subjective measurements, 2) evaluating how PA is associated with NT1 symptoms and comorbidities, and 3) evaluating the effects of an Adapted Physical Activity (APA) program on PA and clinical characteristics.

PATIENTS/METHODS

Patients with NT1 from the National Reference Center of Narcolepsy (Lyon, France) were consecutively included in an APA intervention protocol. Narcolepsy symptoms and comorbidities were collected using standardized questionnaires and sustained attention was evaluated using the Bron-Lyon Attention Stability Test before and after the four-week APA intervention. PA was measured objectively using actigraphy throughout the study.

RESULTS

Twenty-seven NT1 patients were included (median age 14.7 years [8.3-18.4], cataplexy 88.9%, obesity 37.0%). At baseline, 52.4% of the patients had satisfactory PA levels according to international recommendations. Patients with leisure-time PA (LTPA) showed higher quality of life than patients without. 45% of the patients increased PA during the intervention compared to baseline. These responsive patients had more depressive feelings and tended to have lower objective PA than non-responsive patients at baseline. No significant correlation was found between PA levels before and during the intervention and other clinical data.

CONCLUSIONS

Most children with NT1 showed satisfying PA levels despite their daytime sleepiness. LTPA engagement was associated with higher quality of life. An APA intervention could be effective in children with narcolepsy, especially for those with depressive feelings.

Parents' Sleep Multi-Trajectory Modelling from 3 to 36 Months Postpartum in the SEPAGES Cohort

Objective

We investigated maternal and paternal sleep evolution from 3 to 36 months postpartum, their interrelations and predictors in the SEPAGES cohort.

Methods

Sleep information (night sleep duration [NSD], weekend daytime sleep duration [DSD] and subjective sleep loss [SSL]) was collected by self-administered questionnaires at 3, 18, 24 and 36 months postpartum in the SEPAGES French cohort that included 484 mothers and 410 fathers. Group-based multi-trajectory modelling was used to identify maternal, paternal and couple sleep multi-trajectory groups among 188 couples reporting sleep data for at least 2 time points. Multinomial logistic regression was used to assess associations between parental sleep multi-trajectories and early characteristics such as sociodemographic, chronotypes, child sex, birth seasonality or breastfeeding duration.

Results

We identified three maternal (M1-M3), paternal (F1-F3) and couple (C1-C3) sleep multi-trajectory groups with similar characteristics: a group with short NSD and high SSL prevalence (M1, F2, C2), a group with long NSD but medium SSL prevalence (M2, F3, C3) and a group with long NSD and low SSL prevalence (M3, F1, C1). Mothers with the shortest NSD (M1) were less likely to have a partner with long NSD (F2). As compared with long NSD and low SSL prevalence (C1), couples with short NSD and high SSL prevalence (C2) were less likely to have had a first child born in the autumn and fathers in C2 had a later chronotype.

Conclusion

We identified distinct sleep multi-trajectory groups for mothers, fathers and couples from 3- to 36-month postpartum. Sleep patterns within couples were homogeneous.

Does the brain sleep differently depending on intellectual abilities?

AIMS

To compare the children's sleep electroencephalogram according to their intellectual profile.

METHODS

Children were grouped according to their Wechsler Intelligence Scale for Children (WISC) scores (17 with normal intelligence quotient [IQ, NIQ] and 24 with high IQ [HIQ]). Comparisons of spectral power between groups and its relationship with WISC scores were assessed using analyses of variance and linear regression models, adjusted for age and sex.

RESULTS

Children with HIQ had more rapid eye movement (REM) sleep, especially late at night, and more power in slow-frequency bands during REM sleep than those with NIQ. There were also positive associations between the processing speed index and the spectral power in β bands in NREM sleep, and with the spectral power in α, σ, β, and γ bands in REM sleep, with different associations between groups.

CONCLUSION

The enhanced power in slow bands during REM sleep in children with HIQ overlaps with that of typical REM sleep oscillations thought to be involved in emotional memory consolidation. The dissimilar relationships between spectral power and WISC scores in NIQ and HIQ groups may underlie functional differences in brain activity related to cognitive efficiency, questioning the direction of the relationship between sleep and cognitive functioning.

Sleep duration in preschool age and later behavioral and cognitive outcomes: an individual participant data meta-analysis in five European cohorts

Short sleep duration has been linked to adverse behavioral and cognitive outcomes in schoolchildren, but few studies examined this relation in preschoolers. We aimed to investigate the association between parent-reported sleep duration at 3.5 years and behavioral and cognitive outcomes at 5 years in European children. We used harmonized data from five cohorts of the European Union Child Cohort Network: ALSPAC, SWS (UK); EDEN, ELFE (France); INMA (Spain). Associations were estimated through DataSHIELD using adjusted generalized linear regression models fitted separately for each cohort and pooled with random-effects meta-analysis. Behavior was measured with the Strengths and Difficulties Questionnaire. Language and non-verbal intelligence were assessed by the Wechsler Preschool and Primary Scale of Intelligence or the McCarthy Scales of Children's Abilities. Behavioral and cognitive analyses included 11,920 and 2981 children, respectively (34.0%/13.4% of the original sample). In meta-analysis, longer mean sleep duration per day at 3.5 years was associated with lower mean internalizing and externalizing behavior percentile scores at 5 years (adjusted mean difference: - 1.27, 95% CI [- 2.22, - 0.32] / - 2.39, 95% CI [- 3.04, - 1.75]). Sleep duration and language or non-verbal intelligence showed trends of inverse associations, however, with imprecise estimates (adjusted mean difference: - 0.28, 95% CI [- 0.83, 0.27] / - 0.42, 95% CI [- 0.99, 0.15]). This individual participant data meta-analysis suggests that longer sleep duration in preschool age may be important for children's later behavior and highlight the need for larger samples for robust analyses of cognitive outcomes. Findings could be influenced by confounding or reverse causality and require replication.

Longitudinal sleep multi-trajectories from age 1 to 5.5 years and their early correlates: results from the Étude Longitudinale Française depuis l'Enfance birth cohort study

STUDY OBJECTIVES

To identify sleep multi-trajectories in children from age 1 to 5.5 years and their early correlates.

METHODS

We collected early family, maternal, and child characteristics, including children's nighttime sleep duration (NSD) and daytime sleep duration (DSD), night waking (NW), and sleep-onset difficulties (SOD), by parental phone interviews at age 2 months and 1-, 2-, 3.5-, and 5.5 years. Group-based multi-trajectory modeling identified sleep multi-trajectory groups. Multinomial logistic regression assessed associations with early factors.

RESULTS

We identified five distinct sleep multi-trajectory groups for NSD, DSD, NW, and SOD in 9273 included children. The "Good sleepers" (31.6%) and "Long sleepers" (31.0%) groups had low NW and SOD prevalence and shorter NSD but longer DSD in "Good sleepers" than in "Long sleepers." The "Good sleepers but few SOD" group (10.3%) had long NSD and DSD but a SOD peak at age 3.5 years; the "Improving NW and SOD" group (9.6%) showed short but rapidly increasing NSD to a plateau and high but decreasing NW and SOD; the "Persistent NW and SOD" group (17.5%) had persistent high NW and SOD. Maternal depression during pregnancy and sleep habits at age 1 (e.g. parental presence or feeding to fall asleep, sleeping at least part of the night away from own bed) were common risk factors associated with the most disordered sleep multi-trajectory groups.

CONCLUSIONS

We identified distinct sleep multi-trajectory groups and early life-associated factors in preschoolers. Most of the factors associated with the most sleep-disordered multi-trajectory groups are likely modifiable and provide clues for early prevention interventions.

Metabolic disturbances in children with narcolepsy: a retrospective study

STUDY OBJECTIVES

To determine the prevalence of metabolic syndrome (MS) in children with narcolepsy and to evaluate their clinical and sleep characteristics according to the different components of MS.

METHODS

This retrospective study consisted of 58 de novo children with narcolepsy (median age: 12.7 years, 48.3% of boys). The recently published MS criteria in a French population of children were used. Clinical and sleep characteristics were compared between groups with different components of MS.

RESULTS

MS was present in 17.2% of children with narcolepsy, among whom 79.3% presented with high homeostasis model assessment for insulin resistance (HOMA-IR), 25.9% with high body mass index, 24.1% with low high-density lipoprotein cholesterol (HDL-C), and 12.1% with high triglycerides. Patients with at least two MS components had more night eating behaviors and tended to have lower percentage of slow-wave sleep and more fragmented sleep. On multiple sleep latency test, they had shorter mean sleep latencies to rapid eye movement (REM), non-REM sleep and tended to have more sleep onset REM periods (SOREMPs) than those with less than two MS components.

CONCLUSIONS

Insulin resistance was found to be the core metabolic disturbance in obese as well as in nonobese children with narcolepsy. Children with narcolepsy with at least two MS components presented a more severe daytime sleepiness and a higher prevalence of night-eating behaviors than those with less than two MS components. Such children might benefit from early evaluation and management in order to prevent future complications.

Study of the association between cannabis use and sleep disturbances in a large sample of University students

Sleep complaints and cannabis use are common among University students and are related to detrimental effects on health. The aim of this study was to explore their association. This cross-sectional study based on the i-Share e-cohort included French students between 18 and 30 years old (n = 14,787). Frequency of cannabis use was categorized into daily, weekly, monthly, and never/rarely use. Sleep complaints were defined using four items (i.e., insomnia, sleepiness, poor sleep quality, and sleep deprivation). In the whole sample (mean age: 20.4 years, 75.5% of females), 22.7% had insomnia, 18.3% had sleepiness, 22.4% had poor sleep quality, 52.5% had sleep deprivation, and 5.8% used cannabis weekly or daily. After adjustment, the likelihood of insomnia was significantly higher by 45% in cannabis users compared to non-users. The estimates steadily increased with frequency of use, reaching a 2.0-fold higher likelihood of insomnia in daily users compared to never/rarely users. Results were similar for the other sleep complaints. These findings provide support for an association between cannabis use and sleep complaints, particularly insomnia, among University students. Though direction and causality cannot be established in this setting, these results suggest warning students and health professionals about the association between cannabis use and sleep complaints.

French Sleepiness Scale for Adolescents-8 items: A discriminant and diagnostic validation

The objective of the present study was to validate the Short Version of French Sleepiness Scale for Adolescents (FSSA) with eight items (FSSA8).

METHODS

A total of 384 adolescents, aged between 12 and 18 years, completed the FSSA8. These included 269 nonclinical adolescents and 115 adolescents admitted for overnight polysomnography and Multiple Sleep Latency Test (MSLT) because of suspected hypersomnia (85 patients with narcolepsy and 30 with other sleep disorders). Item response theory (IRT) assumptions were tested and psychometric properties were analysed. Matching on sex ratio and age was conducted to estimate concurrent criterion, diagnostic validity and cut-offs.

RESULTS

IRT assumptions were validated confirming the one-dimensionality of the FSSA8. The latent continuum sleepiness for which the scale and its items are reliable encompassed most of the clinical subjects. FSSA8 is weakly correlated with MSLT. Distribution of scores for the nonclinical group and the clinical group differed significantly; the FSSA8 had very good screening validity in sleep disorders. The cut-off was seven points.

CONCLUSION

The FSSA8 appeared to be more reliable for patients than for nonclinical participants and to be a good tool for screening excessive daytime sleepiness in sleep disorders.

Associations between screen use, outdoor time/daylight exposure and sleep changes during the first COVID-19 lockdown in French children from the ELFE and EPIPAGE2 birth cohorts

AIMS

To investigate associations between outdoor and screen time and changes in sleep patterns in children from two nationwide birth-cohorts in the SAPRIS project.

METHODS

During the first French COVID-19 pandemic lockdown, volunteer parents of children enrolled in the ELFE and EPIPAGE2 birth-cohorts completed online questions about their child's outdoor time, screen time, and changes in sleep duration and quality compared with the pre-lockdown situation. In 5700 children (aged 8-9 years, 52% boys) with available data, we assessed associations between outdoor time, screen time, and sleep changes using multinomial logistic regression models adjusted for confounders.

RESULTS

Children spent on average 3 h08 outdoors and 4 h34 using screens/day (3 h27 for leisure, 1 h07 for class-work). Sleep duration increased in 36% of children and decreased in 13.4%; sleep difficulties appeared/increased in 22.5% and decreased/disappeared/remained stable in 18.3%. After adjustment, increased screen time, especially for leisure, was associated with increased and decreased sleep duration (OR(95%CI) = 1.03(1.00-1.06) and OR = 1.06(1.02-1.10), respectively). No association was observed between outdoor time and sleep changes after adjustment.

CONCLUSIONS

Our study adds evidence for the association between high leisure-time screen time and shorter sleep time. It supports current screen guidelines for children, especially during leisure time and for those whose sleep duration is short.

Neurocognitive evaluation of children with down syndrome and obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) treatment has been shown to improve cardiac behavioral and cognitive functions in typically developing children. Early OSAS diagnosis in children with Down syndrome (DS) would be important to prevent its complications, especially cognitive ones, but remains overlooked. The main objective of our study was to assess the cognitive function of children with DS, with and without OSAS. The second objective was to determine the impact of the therapeutic intervention on the cognitive function of children with OSAS. This study included 41 children with DS who underwent polysomnography for OSAS diagnosis and a cognitive evaluation. They were aged between 3.4 and 17.3 years and 24 (59%) were boys. Their median OAHI was 2.6 (0-31)/h of sleep, 30 (73%) were diagnosed with OSAS (15 had mild OSAS, and 15 had moderate/severe OSAS). Some scores of the Raven's colored progressive matrices were negatively correlated with the respiratory arousal index, OAHI tended to be positively correlated with Reiss behavioral problems. 24 (59%) patients received a treatment. Even if we were unable to demonstrate this formally due that only 16 children (39%) accepted a follow-up visit, some displayed improvement in their neuropsychological scores, especially those with moderate/severe OSAS after treatment. Children with DS have low intellectual abilities and more risk of developing OSAS compared to the general population, which may lead to further neurocognitive impairment. Early screening and management are important in this population to prevent any further neurocognitive delay in their development.

Interest of the BLAST paradigm and salivary markers for the evaluation of sleepiness in drivers

Objectives

Sleepiness is associated with decreased cognitive abilities and remains one of the main causes of fatal road accidents. The tools currently available to assess sleepiness, such as questionnaires, are subject to intra- and inter-individual variability, while multiple sleep latency tests are only feasible in few sleep laboratories. The main objective of this study was to explore new potential markers (neurocognitive, biological) to objectively assess sleepiness in drivers.

Methods

A total of 186 drivers (median age 44 years, range 20–74 years, 73% men, 14% obese) were included during a break at a highway service area, in the morning, while on the road for vacation. Questionnaires on sleepiness and sleep characteristics (habitual and on the night before travel), the Bron-Lyon Attention Stability Test (BLAST), and two salivary samples (α-amylase and oxalate) were collected. Associations between measures of sleepiness [Epworth Sleepiness Scale (ESS), and Stanford Sleepiness Scale (SSS)], sleep characteristics, neurocognitive, and biological markers were tested using regression models adjusted for confounding factors.

Results

The night before travel, 83% of the drivers reduced their sleep time and 30% slept 5 h or less. The higher the number of miles to be traveled, the higher the decrease, and the shorter the sleep time. The night before travel, 18 and 24% of the drivers complained of poor sleep quality and difficulty falling asleep. The sleep characteristics on the night before travel were associated with the habitual sleep characteristics. At the time of the test, 47% of the drivers scored pathologically on the SSS. Poor sleep quality and difficulty falling asleep the night before travel were associated with increased sleepiness as assessed by the SSS and decreased attentional ability as assessed by the BLAST. No association between salivary markers and acute sleepiness was observed.

Conclusions

The sleep characteristics of the night before travel were associated with sleepiness and attentional performance. The SSS and the BLAST could be used by individual drivers in a self-evaluation context. Biological markers showed a high variability and limited association with sleep parameters across subjects, emphasizing the need for within-subject designs to assess their usefulness.

Longitudinal associations of DNA methylation and sleep in children: a meta-analysis

BACKGROUND

Sleep is important for healthy functioning in children. Numerous genetic and environmental factors, from conception onwards, may influence this phenotype. Epigenetic mechanisms such as DNA methylation have been proposed to underlie variation in sleep or may be an early-life marker of sleep disturbances. We examined if DNA methylation at birth or in school age is associated with parent-reported and actigraphy-estimated sleep outcomes in children.

METHODS

We meta-analysed epigenome-wide association study results. DNA methylation was measured from cord blood at birth in 11 cohorts and from peripheral blood in children (4-13 years) in 8 cohorts. Outcomes included parent-reported sleep duration, sleep initiation and fragmentation problems, and actigraphy-estimated sleep duration, sleep onset latency and wake-after-sleep-onset duration.

RESULTS

We found no associations between DNA methylation at birth and parent-reported sleep duration (n = 3658), initiation problems (n = 2504), or fragmentation (n = 1681) (p values above cut-off 4.0 × 10^-8). Lower methylation at cg24815001 and cg02753354 at birth was associated with longer actigraphy-estimated sleep duration (p = 3.31 × 10^-8, n = 577) and sleep onset latency (p = 8.8 × 10^-9, n = 580), respectively. DNA methylation in childhood was not cross-sectionally associated with any sleep outcomes (n = 716-2539).

CONCLUSION

DNA methylation, at birth or in childhood, was not associated with parent-reported sleep. Associations observed with objectively measured sleep outcomes could be studied further if additional data sets become available.

Characterization of rapid weight gain phenotype in children with narcolepsy

Objectives

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

Methods

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

Results

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

Conclusions

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

0490 Longitudinal associations between sleep and behavior and cognition in preschoolers from five European birth-cohorts

Introduction

There has been little focus on sleep and its relation to behavior and cognition in preschool-aged children. We aimed to investigate the association between sleep duration in early preschoolers (» 3.5 years of age) and later behavioral and cognitive outcomes (» 5 years of age) in European children.

Methods

We used harmonized data from five cohorts from the EU Child Cohort Network, established by the LifeCycle Project (n=16.444 children): ALSPAC and SWS from UK, EDEN and ELFE from France and INMA from Spain. Within all cohorts, total sleep duration per day and behavioral and cognitive information were reported by parents. Internalizing and externalizing behaviors were measured with the Strengths and Difficulties Questionnaire and treated as percentile scores. Verbal and non-verbal intelligence were assessed by the Wechsler Preschool and Primary Scale of Intelligence or with the McCarthy Scales of Children’s Abilities depending on the cohort and treated as standardized scores. All scores were cohort specific. Associations between sleep duration during early preschool age and later behavior and/or cognition were estimated using linear regression and pooled with two-stage individual participant data meta-analysis adjusted for child, maternal and household information. Analyses were done in DataSHIELD.

Results

Global mean sleep duration was 11h54 ± 1h00 per day at mean age 3.5 years but differed by country, with children from France showing longer sleep duration than children from the UK or Spain. In multivariate meta-analysis, 1 hour of additional sleep duration per day at mean age 3.5 years was associated with reduced internalizing and externalizing behavior percentile scores at mean age 5.1 years (internalizing behavior: badjusted= -1.05, 95%-CI [-1.93, -0.18], I2: 30.3%; externalizing behavior: badjusted= -2.12, 95%-CI [-2.78, -1.47], I2: 0.0%). No association was observed between sleep duration and subsequent verbal or non-verbal intelligence

Conclusion

Longer sleep duration in early preschool age (» 3.5 years of age) was associated with subsequent lower internalizing and externalizing behavior scores (» 5 years of age), but not with verbal or non-verbal intelligence. Adequate sleep duration at an early age is important for children’s later mental health.

Support (If Any)

KG was granted a LifeCycle fellowship.

0168 Subjective and Objective Markers of Sleepiness in Drivers

Introduction

Sleepiness is associated with a decrease in cognitive abilities with effects comparable to those of alcohol. It remains one of the main causes of fatal road accidents. Various tools are available to assess sleepiness subjectively and objectively, such as questionnaires and multiple sleep latency test. However, the former are subject to intra- and inter-individual variability, and the latter is only feasible in a sleep laboratory. The main objective of this study was to explore new potential markers (biological, neurocognitive) to assess sleepiness in drivers. In this perspective, the easy-to-use BLAST attention test allows the evaluation of micro-fluctuations in vigilance. In addition, salivary markers are good physiological markers, easily accessible and non-invasive to collect. Recent studies have suggested that salivary a-amylase and oxalate may be biomarkers of sleep pressure.

Methods

185 drivers (median age 44 years, 72% male, 15% obese) were included during a break at a highway service area, in the morning, while on the road for vacation. Questionnaires on sleepiness, sleep the day before departure, an attention test and two salivary samples (alpha-amylase and oxalate) were taken. Associations between subjective and objective measures of sleepiness, sleep characteristics and salivary concentrations were tested using regression models adjusted for confounding factors.

Results

The night before departure, 57% of drivers reduced their sleep time and more than ¼ slept 5 hours or less. The higher the number of miles to drive, the shorter the sleep time. 16% of the drivers complained of poor sleep quality and difficulty falling asleep. At the time of the test, 46% of the drivers felt drowsy. Poor sleep quality or difficulty falling asleep the night before departure was associated with increased sleepiness as assessed by the Stanford Sleepiness Scale and decreased attentional ability as assessed by the BLAST. No association between salivary samples and sleepiness was observed.

Conclusion

Sleep characteristics on the day before departure were associated with sleepiness and attentional performance. The Stanford Sleepiness Scale and the BLAST could be used by individual drivers in a self-evaluation context.

Support (If Any)

This study was funded by the Vinci Foundation.

Sleep duration trajectories associated with levels of specific serum cytokines at age 5: A longitudinal study in preschoolers from the EDEN birth cohort

Sleep is essential for optimal child development and health during the life course. However, sleep disturbances are common in early childhood and increase the risk of cognitive, metabolic and inflammatory disorders throughout life. Sleep and immunity are mutually linked, and cytokines secreted by immune cells could mediate this interaction. The sleep modulation of cytokines has been studied mostly in adults and adolescents; few studies have focused on school-aged children and none on preschoolers. We hypothesized that night sleep duration affects cytokine levels in preschoolers. In a sample of 687 children from the EDEN French birth cohort, we studied the associations between night sleep duration trajectories from age to 2–5 years old and serum concentrations of four cytokines (Tumor necrosis factor α [TNF-α], Interleukin 6 [IL-6], IL-10, Interferon γ [IFN)-γ] at age 5, adjusting for relevant covariates. As compared with the reference trajectory (≈11h30/night sleep, 37.4% of children), a shorter sleep duration trajectory (<10 ​h/night, 4.5% of children), and changing sleep duration trajectory (≥11h30/night then 10h30/night, 5.6% of children) were associated with higher serum levels of IL-6 and TNF-α, respectively at age 5. We found no associations between sleep duration trajectories and IL-10 or IFN-γ levels. This first longitudinal study among children aged 2–5 years old suggests an impact of sleep duration on immune activity in early childhood. Our study warrants replication studies in larger cohorts to further explore whether and how immune activity interacts with sleep trajectories to enhance susceptibility to adverse health conditions.

TV, computer, tablet and smartphone use and autism spectrum disorder risk in early childhood: a nationally-representative study

Background

Screen media use in early childhood has largely increased in recent years, even more so during the COVID-19 epidemic, and there is much discussion regarding its influence on neurodevelopment, including Autism Spectrum Disorder (ASD).

Methods

We examined the relationship between use of TV, computer, tablet and smartphone at age 2 years and risk of ASD assessed in telephone-based questionnaires among 12,950 children participating in the nationally representative ELFE (‘Etude Longitudinale Française sur les Enfants’) birth cohort study in France.

Results

In inverse-probability weighted (IPW) multinomial regression analyses, children’s weekly or daily screen media use was associated with an increased likelihood of an intermediate risk of ASD (IPW-controlled OR for weekly use:1.07, 95% CI 1.02—1.12; IPW-controlled OR for daily use:1.05, 95% CI 1.02—1.08) but inversely associated with a high risk (IPW-controlled OR for weekly use: 0.60, 95% CI 0.50—0.73; IPW-controlled OR for daily use: 0.75, 95% CI 0.62—0.91), as ascertained by the M-CHAT. This was confirmed when studying TV as well as computer/tablet exposure separately.

Conclusions

Overall, our nationally-representative study conducted among a large sample of 2-year-old children, indicates a complex relationship between screen exposure and ASD risk.

Family-focused contextual factors associated with lifestyle patterns in young children from two mother-offspring cohorts: GUSTO and EDEN

BACKGROUND

Integrated patterns of energy balance-related behaviours of preschool children in Asia are sparse, with few comparative analyses.

PURPOSE

Using cohorts in Singapore (GUSTO) and France (EDEN), we characterized lifestyle patterns of children and investigated their associations with family-focused contextual factors.

METHODS

Ten behavioural variables related to child's diet, walking, outdoor play and screen time were ascertained by parental questionnaires at age 5-6 years. Using principal component analysis, sex-specific lifestyle patterns were derived independently for 630 GUSTO and 989 EDEN children. Contextual variables were organised into distal (family socio-economics, demographics), intermediate (parental health, lifestyle habits) and proximal (parent-child interaction factors) levels of influence and analysed with hierarchical linear regression.

RESULTS

Three broadly similar lifestyle patterns were identified in both cohorts: "discretionary consumption and high screen time", "fruit, vegetables, and low screen time" and "high outdoor playtime and walking". The latter two patterns showed small differences between cohorts and sexes. The "discretionary consumption and high screen time" pattern was consistently similar in both cohorts; distal associated factors were lower maternal education (EDEN boys), no younger siblings (GUSTO boys) and Malay/Indian ethnicity (GUSTO), while intermediate and proximal associated factors in both cohorts and sexes were poor maternal diets during pregnancy, parents allowing high child control over food intake, snacking between meals and having television on while eating.

CONCLUSIONS

Three similar lifestyle patterns were observed among preschool children in Singapore and France. There were more common associated proximal factors than distal ones. Cohort specific family-focused contextual factors likely reflect differences in social and cultural settings. Findings will aid development of strategies to improve child health.

Maturation of Arousals during Day and Night in Preterm Infants

The objective of this study was to compare the maturation of spontaneous arousals during day and night sleep in preterm and term infants. From the Autonomic Baby Evaluation study, the sleep and arousal characteristics of 12 preterm (35.1 ± 2.1 weeks’ gestational age, GA) and 21 term (39.8 ± 0.8 weeks GA) newborns were compared between diurnal and nocturnal sleep periods at birth (M0) and 6 months (M6) of age. Models were adjusted for time (night/day), maturation (M0/M6), prematurity (yes/no). We found that preterm infants had less active sleep (AS)% than term infants with maturation during both day and night sleep, which may reflect accelerated brain maturation secondary to stress or environmental exposure after birth. Moreover, there was a difference in arousal maturation during day and night sleep in the preterm infants, as shown previously for term infants, which suggests the emergence of a circadian rhythm during the earliest postnatal period. We also showed that compared to term infants, these moderate preterm infants had fewer total arousals and, more specifically, fewer arousals in AS during day and night sleep, exposing them to a higher risk of sudden infant death syndrome.

Cerebrospinal Fluid Histamine Levels in Healthy Children and Potential Implication for SIDS: Observational Study in a French Tertiary Care Hospital

OBJECTIVE

A defect of the waking systems could constitute a factor of vulnerability for sudden infant death syndrome (SIDS). A decrease in orexin levels, which promotes wakefulness and activates histaminergic neurons (another hypothalamic wake-promoting system) has already been demonstrated between 2 and 6 months. This work aims to study the levels of histamine (HA), tele-methylhistamine (t-MeHA), its direct metabolite, and t-MeHA/HA ratio in the cerebrospinal fluid (CSF) of healthy children, to evaluate the maturation of the histaminergic system and its possible involvement in SIDS.

METHODS

Seventy Eight French children between 0 and 20 years (48.7% boys) were included, all of whom had a clinical indication for lumbar puncture, but subsequently found to be normal. Measurements of HA and t-MeHA in CSF were performed by reverse phase liquid chromatography coupled to mass spectrometry detection. Statistical analyses were performed using Spearman correlations and Non-parametric pairwise ranking tests.

RESULTS

A negative correlation was found between age and CSF HA (r = -0.44, p < 10^-4) and t-MeHA (r = -0.70, p < 10^-4) levels. In pairwise comparisons, no difference in CSF HA and t-MeHA levels was observed between youngest age groups (i.e., 0-2 mo vs. 3-6 mo), but CSF HA and t-MeHA levels were significantly lower in older children (i.e., >6 mo vs. 0-6 mo). The CSF HA decrease with age was only observed in boys, who also presented global lower CSF HA levels than girls.

CONCLUSION

CSF HA and t-MeHA levels decrease with age in boys, and global levels are lower in boys than in girls. These results reveal changes in histaminergic transmission and metabolism during maturation. Whether lower CSF histamine values in boys compared to girls could contribute to their higher risk of SIDS warrants further research.

Cardiovascular Health at Age 5 Years: Distribution, Determinants, and Association With Neurodevelopment

BACKGROUND

Early childhood may represent an opportune time to commence primordial prevention of cardiovascular disease (CVD, i.e., prevention of risk factors onset), but epidemiological evidence is scarce. We aimed to examine the distribution and parental and early life determinants of ideal cardiovascular health (CVH) in children up to 5 years and to compare the level of cognitive development between children with and without ideal CVH at age 5 years.

METHODS

Using data from the Etude sur les déterminants pré et post natals précoces du Développement psychomoteur et de la santé de l'Enfant (EDEN) study, a French population-based mother-child cohort study, CVH was examined in children at 5 years of age based on the American Heart Association CVH metrics (ideal body mass index, physical activity, diet, blood pressure, cholesterol and glucose levels, and passive smoking, considered in sensitivity analysis only). Children were categorized as having ideal (five to six ideal metrics) or non-ideal CVH (<5 ideal metrics). Intelligence quotient (IQ) at age 5 years was assessed using the French version of the Wechsler Preschool and Primary Scale of Intelligence.

RESULTS

Among the 566 children (55% boys), only 34% had ideal CVH. In fully adjusted logistic regression, boys compared to girls (OR = 1.77, 95% CI 1.13-2.78), children with intermediate (1.77, 1.05-2.98) or ideal (2.58, 1.38-4.82) behavioral CVH at age 3 years and children who spent < 30 min/day watching television (1.91, 1.09-3.34) at age 3 years were more likely to have ideal CVH at age 5 years. At age 5 years, there was a significant 2.98-point difference (95% CI 0.64-5.32) in IQ between children with and without ideal biological CVH after adjusting for confounders.

CONCLUSION

This study highlights that only a third of children aged 5 years had ideal CVH and identified modifiable determinants of ideal CVH and is suggestive of an association between CVH and neurodevelopment at a young age.

Children's mental and behavioral health, schooling, and socioeconomic characteristics during school closure in France due to COVID-19: the SAPRIS project

COVID-19 limitation strategies have led to widespread school closures around the world. The present study reports children's mental health and associated factors during the COVID-19 school closure in France in the spring of 2020. We conducted a cross-sectional analysis using data from the SAPRIS project set up during the COVID-19 pandemic in France. Using multinomial logistic regression models, we estimated associations between children's mental health, children's health behaviors, schooling, and socioeconomic characteristics of the children's families. The sample consisted of 5702 children aged 8-9 years, including 50.2% girls. In multivariate logistic regression models, children's sleeping difficulties were associated with children's abnormal symptoms of both hyperactivity-inattention (adjusted Odds Ratio (aOR) 2.05; 95% Confidence Interval 1.70-2.47) and emotional symptoms (aOR 5.34; 95% CI 4.16-6.86). Factors specifically associated with abnormal hyperactivity/inattention were: male sex (aOR 2.29; 95% CI 1.90-2.76), access to specialized care prior to the pandemic and its suspension during school closure (aOR 1.51; 95% CI 1.21-1.88), abnormal emotional symptoms (aOR 4.06; 95% CI 3.11-5.29), being unschooled or schooled with assistance before lockdown (aOR 2.13; 95% CI 1.43-3.17), and tutoring with difficulties or absence of a tutor (aOR 3.25; 95% CI 2.64-3.99; aOR 2.47; 95% CI 1.48-4.11, respectively). Factors associated with children's emotional symptoms were the following: being born pre-term (aOR 1.34; 95% CI 1.03-1.73), COVID-19 cases among household members (aOR 1.72; 95% CI 1.08-2.73), abnormal symptoms of hyperactivity/inattention (aOR 4.18; 95% CI 3.27-5.34) and modest income (aOR 1.45; 95% CI 1.07-1.96; aOR 1.36; 95% CI 1.01-1.84). Multiple characteristics were associated with elevated levels of symptoms of hyperactivity-inattention and emotional symptoms in children during the period of school closure due to COVID-19. Further studies are needed to help policymakers to balance the pros and cons of closing schools, taking into consideration the educational and psychological consequences for children.

Night-sleep Duration Trajectories and Behavior in Preschoolers: Results from a Prospective Birth Cohort Study

Background: Short sleep duration is associated with concomitant behavioral difficulties, but the longitudinal association between sleep duration and later behavior in early childhood remains unclear. The aim was to study the association between sleep duration trajectories throughout preschool and behavior at age 5-6 years.Participants: 1021 children of the French birth-cohort EDEN were included in this study.Methods: Night-sleep duration trajectories were modeled on the basis of repeated measures collected at age 2, 3 and 5-6 years by parental questionnaires. Behavior was assessed with the Strengths and Difficulties Questionnaire (SDQ), with five subscales measuring conduct problems, emotional symptoms, peer relation problems, antisocial behavior, and hyperactivity-inattention problems. The subscales were dichotomized by the 25th percentile. Multivariable logistic regression, adjusted for baseline behavior, and assessment of multiple confounding factors allowed for studying the independent association between night-sleep duration trajectories from age 2 to 5-6 and behavior at age 5-6.Results: Five distinct sleep-duration trajectories were identified. At age 5-6 years, probability of hyperactivity-inattention problems was increased for boys belonging to the "short sleep" and "medium-low sleep" duration trajectory and girls belonging to the "changing sleep" duration trajectory as compared with children with the medium-high sleep duration trajectory (boys: OR 2.69 [95% CI 1.18-6.16], p = .03 and 1.95 [1.25-3.03], p = .003, and girls: OR 2.79 [1.09- 7.17], p = .03). No associations were observed with the other SDQ subscales.Conclusion: The persistence of short night-sleep durations in preschool years as well as a sudden decrease at age 3 are risk factors of hyperactivity-inattention problems at school start.Abbreviations: SS: short-sleep duration trajectory; MLS: medium-low-sleep duration trajectory; MHS: medium-high-sleep duration trajectory; LS: long-sleep duration trajectory; CS: changing-sleep duration trajectory.

Exposure to screens and children's language development in the EDEN mother-child cohort

Studies in children have reported associations of screen time and background TV on language skills as measured by their parents. However, few large, longitudinal studies have examined language skills assessed by trained psychologists, which is less prone to social desirability. We assessed screen time and exposure to TV during family meals at ages 2, 3 and 5–6 years in 1562 children from the French EDEN cohort. Language skills were evaluated by parents at 2 years (Communicative Development Inventory, CDI) and by trained psychologists at 3 (NEPSY and ELOLA batteries) and 5–6 years (verbal IQ). Cross-sectional and longitudinal associations were assessed by linear regression adjusted for important confounders. Overall, daily screen time was not associated with language scores, except in cross-sectional at age 2 years, where higher CDI scores were observed for intermediate screen time. Exposure to TV during family meals was consistently associated with lower language scores: TV always on (vs never) at age 2 years was associated with lower verbal IQ (− 3.2 [95% IC: − 6.0, − 0.3] points), independent of daily screen time and baseline language score. In conclusion, public health policies should better account for the context of screen watching, not only its amount.

589 Sleep features longitudinally associated with refractive errors in preschoolers

Introduction

Refractive errors are very common, in particular in children and adolescents, leading to global health issues, academic implications and economic costs. The process of emmetropization in child development is a multifactorial and active mechanism, and is yet to be fully understood. Light exposure and endogenous circadian rhythmicity are thought to have an important role in this process. They are also known to be both cause and consequence of various sleep habits. The study aims at investigating the role of sleep duration and timing in refractive error development of preschoolers.

Methods

Sleep duration and timing were assessed at age 2 and 5 years, and vision problems at age 5 through parental auto-questionnaires in 1,130 children from the EDEN birth-cohort. We performed both cross-sectional and longitudinal analyses using logistic regression models, before and after adjusting for age, sex, socio-economic status, nap duration, time spent outdoors and daily screen-time. We conducted multiple imputations to deal with missing data on covariates. The shape of the association was considered by splitting sleep duration into tertiles.

Results

At age 5 years, 20.4% of the children were prescribed glasses (2% for myopia, 11.9% for hyperopia and 6.8% for unknow reason). Children slept on average (SD) 11h05 (30 min) per night at age 2 and 10h49 (48 min) at age 5. Average bedtime and midsleep were 8.36 pm (30 min), 2.06 am (36 min), and 8.54 pm (30 min), 2.06 am (24 min) at age 2 and 5, respectively. In the raw longitudinal analysis, a U-shaped association was observed between nocturnal sleep duration at age 2 and eyeglass prescription at age 5: 2-years-old children sleeping 11h30 had a higher risk to have an eyeglass prescription by the age of 5. Later midsleep and bedtime at age 2 were associated with an increased risk of eyeglass prescription at age 5. All associations, except the one concerning bedtime, were barely changed after adjustment while becoming borderline significant.

Conclusion

Duration and timing of sleep at age 2 were associated with subsequent onset of refractive errors in preschoolers from a general population. Sleep and light hygiene might be targets for prevention.

Support (if any):

594 Sleep Trajectories Between the Age of 2 and 5 are Associated with Blood Cytokine Levels at Age 5 in the EDEN Birth-Cohort Study

Introduction

There is a reciprocal interaction between sleep and the immune system. Activation of the immune system changes the quality of sleep, and sleep regulates innate and adaptive immune responses. While these interactions have been studied in adults and adolescents, only a few studies have focused on school age children and none on preschoolers. Here, we have studied the association between night sleep trajectories between the age of 2 and 5 and serum levels of four cytokines in 5-year-old children.

Methods

A total of 687 children (44% girls) from the EDEN French birth cohort were included. Information on night sleep trajectories between 2 and 5 was available in all included individuals, as well as the levels of Tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, interferon gamma (IFN-gamma), and IL-10 in 5-year-old children. The associations between sleep trajectories and cytokines were assessed by multivariate linear regressions adjusted for socioeconomic, familial, maternal, perinatal and child factors.

Results

A shorter sleep duration trajectory (&lt;10h/night, 4.5% of children) was associated with higher levels of IL-6 when compared to the reference trajectory (≈11h30/night, 37.4% of children). A longer sleep duration trajectory (≥11h3/night, 40.9% of children) was associated with higher levels of IL-10. A changing sleep duration trajectory (≥11h30/night followed by 10h30/night, 5.6% of children) was associated with increased levels of TNF-alpha. No statically significant association was observed between sleep duration trajectories and IFN-gamma.

Conclusion

This first longitudinal study in preschoolers demonstrates an association between sleep duration trajectories and blood levels of IL-6, IL-10 and TNF-alpha. While association does not imply causation, our results are compatible with an impact of sleep duration on low-grade inflammation in preschool children. Should our results be replicated in an independent study sample, it would pave the way for a better understanding of the interactions between sleep and the immune system.

Support (if any):

Longitudinal association between sleep features and refractive errors in preschoolers from the EDEN birth-cohort

Refractive errors are common, especially in children and adolescents, leading to global health issues, academic implications and economic costs. Circadian rhythm and sleep habits may play a role. The study included 1130 children from the EDEN birth-cohort. Data were collected through parental questionnaires at age 2 and 5 for sleep duration and timing, and at age 5 for refractive error. At 5 years, 20.4% were prescribed glasses (2% for myopia, 11.9% for hyperopia and 6.8% for unknown reason). Children slept on average (SD) 11h05/night (± 30 min) and 10h49/night (± 48 min) at age 2 and 5, respectively. Average bedtime and midsleep was 8.36 pm (± 30 min), 2.06 am (± 36 min), and 8.54 pm (± 30 min), 2.06 am (± 24 min) at age 2 and 5, respectively. A U-shaped association was observed between sleep duration at age 2 and eyeglass prescription at age 5. Later midsleep and bedtime at age 2 were associated with an increased risk of eyeglass prescription at age 5. Associations became borderline significant after adjustment for confounding factors. Sleep duration and timing at age 2 were associated with subsequent refractive errors in preschoolers from general population. Sleep hygiene might be a target for refractive errors prevention.

Intellectual Abilities of Children with Narcolepsy

High cognitive functioning could be a protective factor for school difficulties, behavioral and mood impairments in children with narcolepsy. To investigate this factor, we studied the intellectual abilities of 74 children with narcolepsy (43 boys, 11.7 years old at diagnosis, 91% of cataplexies, 64% obese, 100% HLA positive for DR-DQB1*06:02). All children underwent a one-night polysomnography followed by Multiple Sleep Latency Tests, an evaluation of intelligence quotient (IQ), and filled standardized questionnaires. Thirty-eight percent had high potentialities (HP defined by IQ > 130) and 48% had school difficulties. Using non-parametric tests, we found that HP children reported less difficulties at school and tended to have less impulsivity, conduct, and learning disorders than those without HP. They also tended to be less obese and had less desaturation. Using a multivariate regression analysis, we found an association between the REM sleep percentage and the IQ. REM sleep could be involved in the dynamic changes contributing to the equilibrium of intellectual functioning. This study highlights that despite their frequent school difficulties, narcolepsy per se is unlikely to be a cause of intellectual disability in children. Prompt diagnosis and management of comorbidities such as obesity and obstructive sleep apnea (OSA) could improve cognitive and school performances in these children.

Infant feeding practices and sleep at 1 year of age in the nationwide ELFE cohort

Sleep problems reported by parents affect 20% to 30% of infants. Few studies focused on the longitudinal association between infant feeding practices and sleep, especially in France. Analyses were based on 8,696 infants from the French national birth cohort ELFE. Collection of feeding practices from birth to 10 months allowed for the identification of trajectories of use of baby cereals and thickened formula by group‐based trajectory modelling and calculation of duration of any breastfeeding (BF) and age at complementary feeding introduction (CFI) excluding baby cereals. Total sleep duration (TSD), night waking (NW) and sleep onset difficulties (SOD) were reported at age 1. Associations between feeding and sleep were tested by multinomial logistic regressions. BF duration ≥6 months was associated with parent‐reported frequent NW, SOD and TSD ≤ 12 h/24 h at age 1. For TSD and SOD, this association was no longer significant after accounting for parental sleep‐related practices. Early use of baby cereals (≤5 months) was associated with poor sleep. Early CFI (<4 months) was associated with shorter TSD and SOD but not NW. Early use of thickened formula (only <6 months) was related to poor sleep at age 1 (NW and SOD), whereas late (around 6 months) use of thickened formula was associated with better sleep. BF duration ≥6 months was related to poor sleep at age 1 but not after adjustment on 1‐year parental sleep‐related practices except for NW. The use of baby cereals or early CFI was not related to better sleep at age 1.

Clusters of diet, physical activity, television exposure and sleep habits and their association with adiposity in preschool children: the EDEN mother-child cohort

Background

Despite the growing interest in the relation between adiposity in children and different lifestyle clusters, few studies used a longitudinal design to examine a large range of behaviors in various contexts, in particular eating- and sleep-related routines, and few studies have examined these factors in young children. The objectives of this study were to identify clusters of boys and girls based on diet, sleep and activity-related behaviors and their family environment at 2 and 5 years of age, and to assess whether the clusters identified varied across maternal education levels and were associated with body fat at age 5.

Methods

At 2 and 5 years, respectively, 1436 and 1195 parents from the EDEN mother-child cohort completed a questionnaire including behavioral data. A latent class analysis aimed to uncover gender-specific behavioral clusters. Body fat percentage was estimated by anthropometric and bioelectrical impedance measurements. Association between cluster membership and body fat was assessed with mutivariable linear regression models.

Results

At 2 years, two clusters emerged that were essentially characterized by opposite eating habits. At 5 years, TV exposure was the most distinguishing feature, but the numbers and types of clusters differed by gender. An association between cluster membership and body fat was found only in girls at 5 years of age, with girls in the cluster defined by very high TV exposure and unfavorable mealtime habits (despite high outdoor playing and walking time) having the highest body fat. Girls whose mother had low educational attainment were more likely to be in this high-risk cluster. Girls who were on a cluster evolution path corresponding to the highest TV viewing time and the least favorable mealtime habits from 2 to 5 years of age had higher body fat at 5 years.

Conclusions

Efforts to decrease TV time and improve mealtime routines may hold promise for preventing overweight in young children, especially girls growing up in disadvantaged families. These preventive efforts should start as early in life as possible, ideally before the age of two, and should be sustained over the preschool years.

Sleep habits and sleep characteristics at age one year in the ELFE birth cohort study

OBJECTIVE

Infant sleep plays a critical role in normal development. Sleep problems, including sleep onset difficulties (SODs) and night waking (NW), range from 20% to 30% in infants and young children and can be persistent over time up to adulthood. Young French children seem to have longer sleep durations and less sleep troubles than their counterparts worldwide. Here, we aimed at describing infant sleep characteristics (total sleep time (TST)/24 h, NW, and SODs) and associated sleep habits in infants at age one year from the French nationwide birth cohort Etude Longitudinale Française depuis l'Enfance (ELFE).

METHODS

This study included 11,783 infants with information on both sleep characteristics and sleep habits (parental presence when falling asleep, eating to fall asleep, sucking a pacifier or finger to sleep and sleep arrangement and location). Associations were studied by multinomial logistic regression analyses adjusted for familial and infant characteristics.

RESULTS

Mean TST was 13 h36 min including 2 h54 min of naps; 20% of the infants had TST ≤12 h/24 h. About 46% did not present SOD or NW, 16% had frequent SODs and 22% had NW > 1 night in 2. Parental presence, feeding to fall asleep and infant sleep arrangements were frequent in infants with short sleep duration (≤12 h/24 h), NW and SODs. Non-nutritive sucking was associated with risk of NW, SOD and TST >14 h/24 h. Parental room sharing was associated with NW.

CONCLUSION

This work provides new information on infant sleep arrangements and non-nutritive sucking that should be accounted for when considering sleep behaviors. In addition, most identified sleep habits associated with poor sleep characteristics may be amenable to change.

Sleep habits and sleep characteristics at 1 year-old in the ELFE birth cohort study

Key messages

French infants present better sleep characteristics than their counterparts. Most sleep habits associated with poor sleep are accessible to prevention.

Early polysomnographic characteristics associated with neurocognitive development at 36 months of age

BACKGROUND

Few studies on the relationship between sleep quantity and/or quality and cognition have been conducted among preschoolers from the healthy general population. We aimed to identify, among 3-year-old children, early polysomnography (PSG) sleep factors associated with estimated intelligence quotient (IQ) using the Weschler Preschool and Primary Scale Intelligence-III test (WPPSI-III) and its indicators: full-scale (FISQ), verbal (VIQ), and performance (PIQ) intelligence quotients.

METHODS

We included full-term children from the French birth-cohort AuBE with PSG recording at term (M0) and/or six months (M6), and available WPPSI-III scores at three years. Sleep and arousal characteristics of these infants were evaluated during day and night sleep periods. Relationships between IQ scores and sleep parameters were estimated using models with the child as a repeated effect adjusted for time (night/day), maturation (M0/M6), tobacco exposure (yes/no), anxiety-depressive scores during pregnancy, maternal age, duration of breastfeeding and child's gender.

RESULTS

A total of 118 PSG recordings were obtained, representing a total of 78 unique children (38 with one PSG and 40 with two PSG). No correlations were found between night and day sleep durations at M0 or M6. Mean VIQ, PIQ, and FSIQ scores were within normal ranges. In multivariate models, longer sleep duration and higher sleep efficiency during the day were negatively associated with all IQ scores. More frequent arousals during the night were associated with lower VIQ scores.

CONCLUSION

Early sleep characteristics such as night sleep fragmentation or longer naps could be associated with impaired cognitive function at three years of age.

Cord-blood vitamin D level and night sleep duration in preschoolers in the EDEN mother-child birth cohort

OBJECTIVE

Deficiency in 25-hydroxyvitamin D (25OHD) has been associated with sleep disorders in adults. Only three cross-sectional studies were performed in children; which showed an association between 25OHD deficiency and both obstructive sleep apnea syndrome and primary snoring. No longitudinal study has been performed in children from the general population. We analyzed the association between cord-blood vitamin D levels at birth and night-sleep duration trajectories for children between 2 and 5-6 years old in a non-clinical cohort.

METHOD

We included 264 children from the French EDEN mother-child birth-cohort with cord-blood 25OHD level determined by radio-immunoassay at birth, and night-sleep trajectories for children between 2 and 5-6 years old obtained by the group-based trajectory modeling method. Associations between 25OHD and sleep trajectories were assessed by multinomial logistic regression adjusted for maternal and child characteristics.

RESULTS

The trajectories short sleep (<10h30/night), medium-low sleep (10h30-11h00/night), medium-high sleep (≈11h30/night), long sleep (≥11h30/night) and changing sleep (decreased from ≥11h30 to 10h30-11h00/night) represented 5%, 46%, 37%, 4% and 8% of the children, respectively. The mean 25OHD level was 19 ng/ml (SD = 11, range 3-63). It was 12 (SD = 7), 20 (SD = 11), 19 (SD = 10), 14 (SD = 7) and 16 (SD = 8) ng/ml for children with short, medium-low, medium-high, long and changing sleep trajectories, respectively. On adjusted analysis, for each 1-ng/ml decrease in 25OHD level, the odds of belonging to the short sleep versus medium-high sleep trajectory was increased (odds ratio = 1.12, 95% confidence interval [1.01-1.25]). We found no other significant association between 25OHD level and other trajectories.

CONCLUSION

A low 25OHD level at birth may be associated with an increased probability of being a persistent short sleeper in preschool years. These results need confirmation.

Impaired histaminergic neurotransmission in children with narcolepsy type 1

OBJECTIVE

Narcolepsy is a sleep disorder characterized in humans by excessive daytime sleepiness and cataplexy. Greater than fifty percent of narcoleptic patients have an onset of symptoms prior to the age of 18. Current general agreement considers the loss of hypothalamic hypocretin (orexin) neurons as the direct cause of narcolepsy notably cataplexy. To assess whether brain histamine (HA) is also involved, we quantified the cerebrospinal fluid (CSF) levels of HA and tele-methylhistamine (t-MeHA), the direct metabolite of HA between children with orexin-deficient narcolepsy type 1 (NT1) and controls.

METHODS

We included 24 children with NT1 (12.3 ± 3.6 years, 11 boys, 83% cataplexy, 100% HLA DQB1*06:02) and 21 control children (11.2 ± 4.2 years, 10 boys). CSF HA and t-MeHA were measured in all subjects using a highly sensitive liquid chromatographic-electrospray/tandem mass spectrometric assay. CSF hypocretin-1 values were determined in the narcoleptic patients.

RESULTS

Compared with the controls, NT1 children had higher CSF HA levels (771 vs 234 pmol/L, P < 0.001), lower t-MeHA levels (879 vs 1924 pmol/L, P < 0.001), and lower t-MeHA/HA ratios (1.1 vs 8.2, P < 0.001). NT1 patients had higher BMI z-scores (2.7 ± 1.6 vs 1.0 ± 2.3, P = 0.006) and were more often obese (58% vs 29%, P = 0.05) than the controls. Multivariable analyses including age, gender, and BMI z-score showed a significant decrease in CSF HA levels when the BMI z-score increased in patients (P = 0.007) but not in the controls. No association was found between CSF HA, t-MeHA, disease duration, age at disease onset, the presence of cataplexy, lumbar puncture timing, and CSF hypocretin levels.

CONCLUSIONS

Narcolepsy type 1 children had a higher CSF HA level together with a lower t-MeHA level leading to a significant decrease in the t-MeHA/HA ratios. These results suggest a decreased HA turnover and an impairment of histaminergic neurotransmission in narcoleptic children and support the use of a histaminergic therapy in the treatment against narcolepsy.

Circadian nutritional behaviours and cancer risk: New insights from the NutriNet-santé prospective cohort study: Disclaimers

Circadian disruption has been classified as probably carcinogenic to humans by the World Health Organization's International Agency for Research on Cancer. The circadian clock is subject to environmental factors, particularly light exposure and food intake rhythms. However, the association between nutritional circadian behaviours and cancer is not well understood. We investigated the longitudinal associations between number of eating episodes, night-time fasting duration, time of first and last eating episodes, as well as nutritional quality of last eating episode, respectively, with breast and prostate cancer risks, the two main cancer locations in women and men respectively. This prospective study included 41,389 day-working adults in the French NutriNet-Santé cohort (2009-2016) who completed at least three 24 h dietary records during the first 2 years of follow-up. Multivariable Cox models were computed. 1,732 first primary incident cancer cases were diagnosed during the follow-up, among which 428 breast and 179 prostate cancers. After adjustment for covariates including sleep duration, late eaters (last eating episode after 9:30 pm) had an increased risk of breast (Hazard ratio [HR] = 1.48 [1.02-2.17], p = 0.03) and prostate (HR = 2.20 [1.28-3.78], p = 0.004) cancers. However, no association was observed between cancer risk and number of eating episodes, night-time fasting duration, time of first eating episode or macronutrient composition of the last eating episode. This large cohort study suggests that circadian perturbations resulting from late time of last food intake may be involved in carcinogenesis at different locations. Beyond nutritional quality of food intake, nutritional circadian regulation should be further investigated in the context of cancer prevention.

Night sleep duration trajectories and associated factors among preschool children from the EDEN cohort

OBJECTIVE

Sleep duration may vary both interindividually and intraindividually over time. We aimed to identify night-sleep duration (NSD) trajectories among preschoolers and to study associated factors.

METHODS

NSD was collected within the French birth-cohort study EDEN at ages 2, 3, and 5-6 years through parental questionnaires, and were used to model NSD trajectories among 1205 children. Familial socioeconomic factors, maternal sociodemographic, health and lifestyle characteristics, as well as child health, lifestyle, and sleep characteristics at birth and/or at age two years were investigated in association with NSD using multinomial logistic regressions.

RESULTS

Five distinct NSD trajectories were identified: short (SS, <10 h, 4.9%), medium-low (MLS, <11 h, 47.8%), medium-high (MHS, ≈11.5 h, 37.2%), long (LS, ≥11.5 h, 4.5%) and changing (CS, ie, ≥11.5 h then <11 h, 5.6%) NSD trajectories. Multivariable analyses showed in particular that compared to the MHS trajectory factors associated with increased risk for the SS trajectory were male gender, first child, maternal age and working status, night-waking, parental presence when falling asleep, television-viewing duration, as well as both "Processed and fast foods" and the "Baby food" dietary patterns at age two years. Factors positively associated with the CS trajectory were maternal smoking, feeding at night, and the Processed and fast foods dietary pattern at age two years, whereas child's activity and emotionality scores at age one year were negatively associated.

CONCLUSION

We identified distinct NSD trajectories among preschoolers and associated early life factors. Some of them may reflect less healthy lifestyles, providing cues for early multi-behavioral prevention interventions.