Nocturnal sleep duration trajectories in early childhood and school performance at age 10 years.

Sleep plays a fundamental role in brain development and resultant functions. The aim was to verify whether nocturnal sleep duration during early childhood has long-term associations with academic achievement at age 10 years. The present study is part of the Quebec Longitudinal Study of Child Development, a representative cohort of infants born in 1997-1998 in the province of Quebec, Canada. Children with known neurological conditions were excluded from this cohort. Four trajectories of parent-reported nocturnal sleep duration at ages 2.5, 3, 4, 5 and 6 years were determined using a SAS procedure named PROC TRAJ. Sleep duration at age 10 years was also reported. Teachers provided data on academic performance when the children were age 10 years. These data were available for 910 children (430 boys, 480 girls; 96.6% Caucasians). Univariate and multivariable logistic regressions were performed using SPSS. Children who slept less than 8 hr per night at 2.5 years but normalized later on (Traj1) had three-five times the odds of having grades below the class average in reading, writing, mathematics and science compared with children who slept sufficiently (Traj3-4: 10-11 hr per night). Children who slept about 9 hr per night throughout childhood (Traj2) had two-three times the odds of being below the class average in mathematics and science. Sleep duration at age 10 years was not correlated with the academic performance. These results point to the presence of a very important early period during which sufficient sleep is needed to fine-tune the functions necessary for academic achievement later on.

Childhood restless legs syndrome: A longitudinal study of prevalence and familial aggregation.

Restless legs syndrome is a relatively common neurological disorder in adults. In childhood, however, its prevalence and genetic contribution are still largely unknown. The objectives of this study were to assess the prevalence of restless legs syndrome (RLS) during childhood and adolescence in a large population-based cohort and evaluate the degree of association with parental history. Data from a large, prospective longitudinal cohort from the Quebec Longitudinal Study of Child Development of 1,856 children born in 1997-1998 were studied from 2005 to 2013. The prevalence of RLS was assessed at ages 7, 8, 12, 13 and 15 years through a questionnaire completed by the mother. Parental history of RLS was also queried. Between 7 and 15 years of age, the yearly prevalence of RLS ranged from 2.4% to 3.1%, with a higher prevalence in boys than girls at 12 years old. The prevalence of RLS at any time during this period was 8.6% but only 1.8% of parents answered positively at least twice during the longitudinal study. This low persistent rate could be explained by remissions or the use of parental report. The prevalence was higher when there was at least one parent affected with RLS (13.0%) compared to children without a parental history (6.9%). Findings from this population-based study confirm the high prevalence of RLS in children aged 7-15 years and corroborate the strong familial aggregation for RLS. Parents should be encouraged to inform the paediatrician about the presence of RLS in the family to help the diagnostic process.

Phosphorylation of ARHGAP19 by CDK1 and ROCK regulates its subcellular localization and function during mitosis.

ARHGAP19 is a hematopoietic-specific Rho GTPase-activating protein (RhoGAP) that acts through the RhoA/ROCK pathway to critically regulate cell elongation and cytokinesis during lymphocyte mitosis. We report here that, during mitosis progression, ARHGAP19 is sequentially phosphorylated by the RhoA-activated kinases ROCK1 and ROCK2 (hereafter ROCK) on serine residue 422, and by CDK1 on threonine residues 404 and 476. The phosphorylation of ARHGAP19 by ROCK occurs before mitosis onset and generates a binding site for 14-3-3 family proteins. ARHGAP19 is then phosphorylated by CDK1 in prometaphase. The docking of 14-3-3 proteins to phosphorylated S422 protects ARHGAP19 from dephosphorylation of the threonine sites and prevents ARHGAP19 from relocating to the plasma membrane during prophase and metaphase, thus allowing RhoA to become activated. Disruption of these phosphorylation sites results in premature localization of ARHGAP19 at the cell membrane and in its enrichment to the equatorial cortex in anaphase leading to cytokinesis failure and cell multinucleation.

Association Between Peer Victimization and Parasomnias in Children: Searching for Relational Moderators.

This cross-sectional study examined the moderating role of support from three key figures (mothers, teachers, friends) in the association between peer victimization and parasomnias in childhood. The sample consisted of 1150 children aged 8 years who attended elementary school. Controlling for potential confounders, hierarchical multiple regressions revealed that peer victimization was associated with a higher level of parasomnias, equally for both girls and boys. However, for girls, the predictive association of peer victimization with parasomnias was moderated by the level of support in relationships with either their parents, their teachers, or their friends. The findings suggest that somatic symptoms such as sleep problems may be a first indicator that a child is being bullied. Because parents, teachers as well as friends can play a key role in preventing the development of parasomnias, it may be useful to help bullied children develop strong bonds within at least one of these relationships.

The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes.

Small GTP-binding proteins of the Rho family orchestrate the cytoskeleton remodelling events required for cell division. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) promote cycling of Rho GTPases between the active GTP-bound and the inactive GDP-bound conformations. We report that ARHGAP19, a previously uncharacterised protein, is predominantly expressed in hematopoietic cells and has an essential role in the division of T lymphocytes. Overexpression of ARHGAP19 in lymphocytes delays cell elongation and cytokinesis. Conversely, silencing of ARHGAP19 or expression of a GAP-deficient mutant induces precocious mitotic cell elongation and cleavage furrow ingression, as well as excessive blebbing. In relation to these phenotypes, we show that ARHGAP19 acts as a GAP for RhoA, and controls recruitment of citron and myosin II to the plasma membrane of mitotic lymphocytes as well as Rock2-mediated phosphorylation of vimentin, which is crucial to maintain the stiffness and shape of lymphocytes. In addition to its effects on cell shape, silencing of ARHGAP19 in lymphocytes also impairs chromosome segregation.

Short persistent sleep duration is associated with poor receptive vocabulary performance in middle childhood.

The aim of this study was to examine whether short sleep duration is associated with poor receptive vocabulary at age 10 years. In the Quebec Longitudinal Study of Child Development, parents reported their children's nocturnal sleep duration annually from ages 2.5 to 10 years, and children were assessed for receptive vocabulary using the Peabody Picture Vocabulary Test-Revised (PPVT-R) at ages 4 and 10 years. Groups with distinct nocturnal sleep duration trajectories were identified and the relationships between sleep trajectories and poor PPVT-R performance were characterized. In all, 1192 children with available sleep duration and PPVT-R data participated in this epidemiological study. We identified four longitudinal nocturnal sleep trajectories: short persistent sleepers (n = 72, 6.0%), short increasing sleepers (n = 47, 3.9%), 10-h sleepers (n = 628, 52.7%) and 11-h sleepers (n = 445, 37.3%). In all, 14.8% of the children showed poor PPVT-R performance at age 10 years. Nocturnal sleep trajectories and poor PPVT-R performance at age 10 were associated significantly (P = 0.003). After adjusting for baseline receptive vocabulary performance at age 4 and other potential confounding variables, logistic regression analyses suggest that, compared to 11-h sleepers, the odds ratio of presenting poor receptive vocabulary at age 10 was 2.67 [95% confidence interval (CI): 1.24-5.74, P = 0.012] for short persistent sleepers and 1.66 (95% CI: 1.06-2.59, P = 0.026) for 10-h sleepers. These results corroborate previous findings in early childhood, and indicate that short sleep duration is associated with poor receptive vocabulary during middle childhood.

Sleep deprivation impairs inhibitory control during wakefulness in adult sleepwalkers.

Sleepwalkers often complain of excessive daytime somnolence. Although excessive daytime somnolence has been associated with cognitive impairment in several sleep disorders, very few data exist concerning sleepwalking. This study aimed to investigate daytime cognitive functioning in adults diagnosed with idiopathic sleepwalking. Fifteen sleepwalkers and 15 matched controls were administered the Continuous Performance Test and Stroop Colour-Word Test in the morning after an overnight polysomnographic assessment. Participants were tested a week later on the same neuropsychological battery, but after 25 h of sleep deprivation, a procedure known to precipitate sleepwalking episodes during subsequent recovery sleep. There were no significant differences between sleepwalkers and controls on any of the cognitive tests administered under normal waking conditions. Testing following sleep deprivation revealed significant impairment in sleepwalkers' executive functions related to inhibitory control, as they made more errors than controls on the Stroop Colour-Word Test and more commission errors on the Continuous Performance Test. Sleepwalkers' scores on measures of executive functions were not associated with self-reported sleepiness or indices of sleep fragmentation from baseline polysomnographic recordings. The results support the idea that sleepwalking involves daytime consequences and suggest that these may also include cognitive impairments in the form of disrupted inhibitory control following sleep deprivation. These disruptions may represent a daytime expression of sleepwalking's pathophysiological mechanisms.

Longitudinal study of childhood sleep trajectories and adolescent mental health problems.

Study Objective: To investigate whether childhood sleep trajectories are associated with mental health symptoms such as social phobia, generalized anxiety, depression, attention deficit hyperactivity disorder (ADHD), conduct problems, and opposition at age 15. Methods: A total of 2120 children took part in the Quebec Longitudinal Study of Child Development. Childhood sleep trajectories were computed from maternal reports at 2.5, 3.5, 4, 6, 8, 10, and/or 12 years. At age 15, 1446 adolescents filled out mental health and sleep questions. A path analysis model was assessed in the full sample. Results: Four childhood nocturnal sleep duration trajectories were identified: (1) a short pattern (7.5%), (2) a short-increasing pattern (5.8%), (3) a 10 hours pattern (50.7%), and (4) an 11 hours pattern (36.0%). Three childhood sleep latency trajectories were found: (1) a short pattern (31.7%), (2) an intermediate pattern (59.9%), and (3) a long pattern (8.4%). Finally, two childhood wakefulness after sleep-onset trajectories were found: (1) a normative pattern (73.0%) and (2) a long pattern (27.0%). The path analysis model indicated that children following a long childhood sleep latency trajectory were more likely to experience symptoms of depression (ß = 0.06, 95% CI: 0.01 to 0.12), ADHD (ß = 0.07, 95% CI: 0.02 to 0.13), conduct problems (ß = 0.05, 95% CI: 0.00 to 0.10) and opposition (ß = 0.08, 95% CI: 0.02 to 0.13) at age 15. Conclusions: This longitudinal study revealed that children presenting a long sleep latency throughout childhood are at greater risk of symptoms of depression, ADHD, conduct problems, and opposition in adolescence.

Reduced rapid eye movement sleep in late middle-aged and older apolipoprotein E ɛ4 allele carriers.

STUDY OBJECTIVES: Apolipoprotein E ɛ4 (APOE4) is the strongest genetic risk factor for Alzheimer's disease (AD). In addition, APOE4 carriers may exhibit sleep disturbances, but conflicting results have been reported, such that there is no clear consensus regarding which aspects of sleep are impacted. Our objective was to compare objective sleep architecture between APOE4 carriers and non-carriers, and to investigate the modulating impact of age, sex, cognitive status, and obstructive sleep apnea (OSA). METHODS: A total of 198 dementia-free participants aged >55 years old (mean age: 68.7 ± 8.08 years old, 40.91% women, 41 APOE4 carriers) were recruited in this cross-sectional study. They underwent polysomnography, APOE4 genotyping, and a neuropsychological evaluation. ANCOVAs assessed the effect of APOE4 status on sleep architecture, controlling for age, sex, cognitive status, and the apnea-hypopnea index. Interaction terms were added between APOE4 status and covariates. RESULTS: Rapid eye movement (REM) sleep percentage (F = 9.95, p = .002, ηp2 = 0.049) and duration (F = 9.23, p = .003, ηp2 = 0.047) were lower in APOE4 carriers. The results were replicated in a subsample of 112 participants without moderate-to-severe OSA. There were no significant interactions between APOE4 status and age, sex, cognitive status, and OSA in the whole sample. CONCLUSIONS: Our results show that APOE4 carriers exhibit lower REM sleep duration, including in cognitively unimpaired individuals, possibly resulting from early neurodegenerative processes in regions involved in REM sleep generation and maintenance.

REM sleep is associated with the volume of the cholinergic basal forebrain in aMCI individuals.

BACKGROUND: Rapid-eye movement (REM) sleep highly depends on the activity of cholinergic basal forebrain (BF) neurons and is reduced in Alzheimer's disease. Here, we investigated the associations between the volume of BF nuclei and REM sleep characteristics, and the impact of cognitive status on these links, in late middle-aged and older participants. METHODS: Thirty-one cognitively healthy controls (66.8 ± 7.2 years old, 13 women) and 31 participants with amnestic Mild Cognitive Impairment (aMCI) (68.3 ± 8.8 years old, 7 women) were included in this cross-sectional study. All participants underwent polysomnography, a comprehensive neuropsychological assessment and Magnetic Resonance Imaging examination. REM sleep characteristics (i.e., percentage, latency and efficiency) were derived from polysomnographic recordings. T1-weighted images were preprocessed using CAT12 and the DARTEL algorithm, and we extracted the gray matter volume of BF regions of interest using a probabilistic atlas implemented in the JuBrain Anatomy Toolbox. Multiple linear regressions were performed between the volume of BF nuclei and REM sleep characteristics controlling for age, sex and total intracranial volume, in the whole cohort and in subgroups stratified by cognitive status. RESULTS: In the whole sample, lower REM sleep percentage was significantly associated to lower nucleus basalis of Meynert (Ch4) volume (ß = 0.32, p = 0.009). When stratifying the cohort according to cognitive status, lower REM sleep percentage was significantly associated to both lower Ch4 (ß = 0.48, p = 0.012) and total BF volumes (ß = 0.44, p = 0.014) in aMCI individuals, but not in cognitively unimpaired participants. No significant associations were observed between the volume of the BF and wake after sleep onset or non-REM sleep variables. DISCUSSION: These results suggest that REM sleep disturbances may be an early manifestation of the degeneration of the BF cholinergic system before the onset of dementia, especially in participants with mild memory deficits.

Sex differences in the association between sleep duration, diet and body mass index: a birth cohort study.

Sex differences in the effects of sleep duration on dietary intake and eating behaviours were examined prospectively in relation to overweight/obesity at ages 6 and 7. Using data from a representative sample (QLSCD 1998-2010) of children born in the province of Québec (Canada), 1106 children were followed to age 6 and 1015 to 7years. Average nocturnal sleep duration was surveyed annually from 2.5-6years, food-frequency and eating behaviour questionnaires were administered at age 6, and body weight and height were measured at 6 and 7years. Associations were examined longitudinally and mediation examined with adjustments for potential confounders. In boys and girls, shorter sleep duration patterns were associated significantly with less favourable dietary intakes at 6years: boys consumed vegetables and fruits less frequently and meats/alternatives more frequently than boys with longer sleep patterns; and girls consumed vegetables, fruits and milk products less frequently and soft-drinks more frequently than girls with longer sleep patterns. However, boys with shorter sleep patterns were also more likely to eat at irregular hours or to eat too much/fast at 6years. These behaviours, and not dietary intake, mediated an inverse association between sleep duration and overweight/obesity in boys. Sleep duration did not associate with any problem eating behaviours or overweight/obesity in girls. Shorter sleep in early childhood appears to associate with problematic eating behaviours in boys and diet quality in both sexes, regardless of an association with overweight/obesity. This is important for public health and should be considered in relation to other diet-related diseases.

Testing Bidirectional, Longitudinal Associations Between Disturbed Sleep and Depressive Symptoms in Children and Adolescents Using Cross-Lagged Models.

Importance: Understanding the longitudinal, bidirectional associations between disturbed sleep and depression in childhood and adolescence is crucial for the development of prevention and intervention programs. Objective: To test for bidirectional associations and cascade processes between disturbed sleep and depressive symptoms covering both childhood and adolescence and to test for the moderating processes of sex and pubertal status in adolescence. Design, Setting, and Participants: A prospective cohort study using the Québec Longitudinal Study of Child Development (QLSCD; 1997-ongoing). QLSCD's objective is to identify early childhood factors associated with long-term psychosocial and academic adjustment. Data were collected across 8 waves between ages 5 years (2003) and 17 years (2015). Associations were tested through cross-lagged models in childhood (5, 7, and 8 years), and in adolescence (10, 12, 13, 15, and 17 years). Data were analyzed from February to October 2021. Main Outcomes and Measures: Primary outcomes were disturbed sleep and depressive symptoms. Disturbed sleep was parent-reported and included sleep duration, time awake in bed, daytime sleepiness, sleep talking, sleepwalking, night terrors, and nightmares. Depressive symptoms were parent-reported in childhood (Child Behavior Checklist and Revised Ontario Child Health Study Scales), and self-reported in adolescence (Mental Health and Social Inadaptation Assessment for Adolescents). Results: Data on 1689 children (852 female [50.4%]) and 1113 adolescents (595 female [53.5%]) were included in the analyses. In childhood, significant bidirectional associations between depressive symptoms and disturbed sleep at all time points were found, indicating cascade processes (range ß = 0.07; 95% CI, 0.02-012 to ß = 0.15; 95% CI, 0.10-0.19). In adolescence, significant bidirectional associations from depressive symptoms to disturbed sleep (ß = 0.09; 95% CI, 0.04-0.14) and vice versa (ß = 0.10; 95% CI, 0.04-0.16) between 10 and 12 years were found. Between 12 and 13 years, depressive symptoms were modestly associated with disturbed sleep (ß = 0.05; 95% CI, 0.001-0.10) but the reverse association was not significant. Cross-lagged estimates were nonsignificant after 13 years. The associations did not vary as a function of either sex or puberty-by-sex. Conclusions and Relevance: These findings suggest that disturbed sleep is associated with the consolidation of depressive symptoms starting in childhood, which, in turn, is associated with ongoing sleep problems. It is possible that timely and appropriate interventions for incipient disturbed sleep and depression prevent spiraling effects on both domains.

National strategy on the integration of sleep and circadian rhythms into public health research and policies: Report from the Canadian Sleep and Circadian Network.

Scientists in sleep and circadian rhythms, public health experts, healthcare providers, partners, and stakeholders convened in 2020 for a 2-day meeting organized by the Canadian Sleep and Circadian Network to develop a national strategy for integrating sleep and circadian rhythms into public health and policies in Canada. The objective of this paper is to present the national strategy that emerged from this meeting of 60 participants from across Canada. The meeting focused on 4 key target priorities: (1) atypical working schedules, (2) sleep and circadian rhythms of children and adolescents, (3) insomnia, and (4) impact of sleep apnea on health. Following constructive discussions, it was decided that the following 4 strategic objectives should be prioritized to accelerate the integration of sleep and circadian rhythms into public health policies in Canada: (1) increase public health sleep and circadian rhythm research, (2) increase public health education and knowledge mobilization on sleep, (3) inform and support public health sleep interventions and policies, and (4) promote sleep health training. Participants recommended that research and public health efforts address needs along the continuum of sleep health. The committee noted that strategies and interventions could differ across contexts, settings, sectors, and jurisdictions. The national strategy also identified high-priority research questions in public health and recommended mechanisms to build research capacity, providing a path forward for the integration of sleep and circadian rhythms into public health research and policies.

Medial temporal lobe and obstructive sleep apnea: Effect of sex, age, cognitive status and free-water.

Medial temporal structures, namely the hippocampus, the entorhinal cortex and the parahippocampal gyrus, are particularly vulnerable to Alzheimer's disease and hypoxemia. Here, we tested the associations between obstructive sleep apnea (OSA) severity and medial temporal lobe volumes in 114 participants aged 55-86 years (35 % women). We also investigated the impact of sex, age, cognitive status, and free-water fraction correction on these associations. Increased OSA severity was associated with larger hippocampal and entorhinal cortex volumes in women, but not in men. Greater OSA severity also correlated with increased hippocampal volumes in participants with amnestic mild cognitive impairment, but not in cognitively unimpaired participants, regardless of sex. Using free-water corrected volumes eliminated all significant associations with OSA severity. Therefore, the increase in medial temporal subregion volumes may possibly be due to edema. Whether these structural manifestations further progress to neuronal death in non-treated OSA patients should be investigated.

Short sleep duration and body mass index: a prospective longitudinal study in preadolescence.

Short sleep duration is associated with incidence of overweight and obesity in preadolescent children. The authors performed regression analyses on data from the Quebec Longitudinal Study of Kindergarten Children (1986-1987), a prospective cohort study comprising 1,916 preadolescent children in Canada. The aim was to assess associations between time spent in bed and body mass index reported by mothers after adjusting for numerous confounding factors, such as pubertal status. Time-in-bed and body mass index trajectories were computed using a semiparametric model mixture. Time-in-bed trajectories were classified as short (15% of the preadolescents), 10.5-hour (68%), and 11-hour (17%) sleep-duration trajectories, decreasing over time. Body mass index trajectories were classified as normal weight (68% of the preadolescents), overweight (27%), and obese (5%). The short sleep trajectory was associated with an increased odds ratio of being in the overweight body mass index trajectory (odds ratio (OR)=1.55, 95% confidence interval (CI): 1.39, 1.71) or in the obese body mass index trajectory (OR=3.26, 95% CI: 3.20, 3.29) compared with the 11-hour trajectory. One hour less of sleep per night at 10 years of age was associated with an increased odds ratio of being overweight (OR=1.51, 95% CI: 1.28, 1.76) or obese (OR=2.07; 95% CI: 1.51, 2.84) at 13 years of age.

Sleep in times of crises: A scoping review in the early days of the COVID-19 crisis.

During the early days of the pandemic and in the context of a seemingly unknown global threat, several potential major sleep disruptors were identified by sleep researchers and practitioners across the globe. The COVID-19 pandemic combined several features that, individually, had been shown to negatively affect sleep health in the general population. Those features included state of crisis, restrictions on in-person social interactions, as well as financial adversity. To address the lack of a comprehensive summary of sleep research across these three distinctive domains, we undertook three parallel systematic reviews based on the following themes: 1) Sleep in times of crises; 2) Sleep and social isolation; and 3) Sleep and economic uncertainty. Using a scoping review framework, we systematically identified and summarized findings from these three separated bodies of works. Potential moderating factors such as age, sex, ethnicity, socioeconomic status, psychological predisposition, occupation and other personal circumstances are also discussed. To conclude, we propose novel lines of research necessary to alleviate the short- and long-term impacts of the COVID-19 crises and highlight the need to prepare the deployment of sleep solutions in future crises.

Finasteride metabolism and pharmacogenetics: new approaches to personalized prevention of prostate cancer.

Incidences of prostate cancer in most countries are increasing owing to better detection methods; however, prevention with the use of finasteride, a very effective steroid 5α-reductase type II inhibitor, has been met with mixed success. A wide interindividual variation in response exists and is thought to be due to heritable factors. This article summarizes the literature that attempts to elucidate the molecular mechanisms of finasteride in terms of its metabolism, excretion and interaction with endogenous steroid molecules. We describe previously reported genetic variations of steroid-metabolizing genes and their potential association with finasteride efficacy. Based on the literature, we outline directions of research that may contribute to understanding the interindividual variation in finasteride prevention and to the future development of personalized medicine.

Sleep following sport-related concussions.

OBJECTIVES: Sleep and vigilance disorders are among the most commonly reported symptoms following a concussion. The aim of the study was thus to investigate the effects of sport-related concussions on subjective and objective sleep quality. METHODS: Ten concussed athletes and 11 non-concussed athletes were included. Concussed athletes had a history of 4.6+/-2.1 concussions with at least one concussion during the last year. They were recorded for two consecutive nights in the laboratory and during a 10-min period of wakefulness. They completed questionnaires related to sleep quality and symptoms as well as neuropsychological tests and the CogSport computer battery. RESULTS: Concussed athletes reported more symptoms and worse sleep quality than control athletes, but no between-group differences were found on polysomnographic variables or on REM and NREM sleep quantitative EEG variables. However, concussed athletes showed significantly more delta activity and less alpha activity during wakefulness than did control athletes. CONCLUSION: In spite of the subjective complaints in sleep quality of concussed athletes, no change was observed in objective sleep characteristics. However, concussions were associated with an increase in delta and a reduction in alpha power in the waking EEG. Sport-related concussions are thus associated with wakefulness problems rather than sleep disturbances.

Associations between sleep duration patterns and overweight/obesity at age 6.

OBJECTIVE: To investigate whether longitudinal sleep duration patterns during early childhood is a risk factor of overweight or obesity at school entry while controlling for a variety of obesogenic environmental factors. DESIGN, SETTING, AND PARTICIPANTS: This is a prospective cohort study (March-December 1998 to December 2004) of a representative sample of infants born in 1997-1998 in the Canadian province of Quebec. Body mass index (BMI) was measured at ages 2.5 and 6 years. Sleep duration was reported yearly from 2.5 to 6 years of age by their mothers. Prenatal, postnatal (5 and 29 months), and lifestyle (6 y) potentially confounding factors for excess weight were assessed by interviews, questionnaires and hospital records. A group-based semiparametric mixture model was used to estimate developmental patterns of sleep duration. The relationship between sleep duration patterns and BMI was tested using multivariate logistic regression models to control for potentially confounding factors on 1138 children. RESULTS: Four sleep duration patterns were identified: short persistent (5.2%), short increasing (4.7%), 10-hour persistent (50.7%), and 11-hour persistent (39.4%). After controlling for potentially confounding factors, the risk for overweight or obesity was almost 4.2 times higher for short persistent sleepers (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.6 to 11.1; P = 0.003) than for 11-hour persistent sleepers. CONCLUSIONS: Persistently short sleep duration (<10 h) during early childhood significantly increases the risk of excess weight or obesity in childhood, and appears to be independent of other obesogenic factors.

Biomarkers of dementia in obstructive sleep apnea.

Epidemiologic and mechanistic evidence is increasingly supporting the notion that obstructive sleep apnea is a risk factor for dementia. Hence, the identification of patients at risk of cognitive decline due to obstructive sleep apnea may significantly improve preventive strategies and treatment decision-making. Cerebrospinal fluid and blood biomarkers obtained through genomic, proteomic and metabolomic approaches are improving the ability to predict incident dementia. Therefore, fluid biomarkers have the potential to predict vulnerability to neurodegeneration in individuals with obstructive sleep apnea, as well as deepen our understanding of pathophysiological processes linking obstructive sleep apnea and dementia. Many fluid biomarkers linked to Alzheimer's disease and vascular dementia show abnormal levels in individuals with obstructive sleep apnea, suggesting that these conditions share common underlying mechanisms, including amyloid and tau protein neuropathology, inflammation, oxidative stress, and metabolic disturbances. Markers of these processes include amyloid-ß, tau proteins, inflammatory cytokines, acute-phase proteins, antioxydants and oxidized products, homocysteine and clusterin (apolipoprotein J). Thus, these biomarkers may have the ability to identify adults with obstructive sleep apnea at high risk of dementia and provide an opportunity for therapeutic intervention. Large cohort studies are necessary to establish a specific fluid biomarker panel linking obstructive sleep apnea to dementia risk.