Metabolic alterations in children with obstructive sleep apnea

Sex differences in cardiac transcriptomic response to neonatal sleep apnea

Pediatric obstructive sleep apnea poses a significant health risk, with potential long-term consequences on cardiovascular health. This study explores the dichotomous nature of neonatal cardiac response to chronic intermittent hypoxia (CIH) between males and females, aiming to fill a critical knowledge gap in the understanding of sex-specific cardiovascular consequences of sleep apnea in early life. Neonates were exposed to CIH until p28 and underwent comprehensive in vivo physiological assessments, including whole-body plethysmography, treadmill stress-tests, and echocardiography. Results indicated that male CIH rats weighed 13.7% less than age-matched control males (p = 0.0365), while females exhibited a mild yet significant increased respiratory drive during sleep (93.94 ± 0.84 vs. 95.31 ± 0.81;p = 0.02). Transcriptomic analysis of left ventricular tissue revealed a substantial sex-based difference in the cardiac response to CIH, with males demonstrating a more pronounced alteration in gene expression compared to females (5986 vs. 3174 genes). The dysregulated miRNAs in males target metabolic genes, potentially predisposing the heart to altered metabolism and substrate utilization. Furthermore, CIH in males was associated with thinner left ventricular walls and dysregulation of genes involved in the cardiac action potential, possibly predisposing males to CIH-related arrhythmia. These findings emphasize the importance of considering sex-specific responses in understanding the cardiovascular implications of pediatric sleep apnea.

Obstructive sleep related breathing disorders and cardiometabolic risk factors - A Portuguese birth cohort

BACKGROUND

Pediatric obstructive sleep related breathing disorders (SRBD) are an important under-diagnosed health problem with associated cardiometabolic comorbidities, demonstrated with polysomnographic studies in selected samples. Our main goal was to assess the prevalence of SRBD in a population-based cohort and to analyze its association with cardiometabolic risk factors, in general and by sex.

METHODS

Pediatric Sleep Questionnaire (PSQ) was applied to parents of 7-years-old children evaluated in the birth cohort, Generation XXI. Sex, anthropometrics, blood pressure (BP), lipid profile, glucose, insulin, HOMA-IR, and high-sensitivity C-reactive protein were compared among children with/without SRBD, using Chi-square, Mann-Whitney tests and logistic regression models.

RESULTS

A total of 1931 children (51.2 % boys) were included; 17.5 % were overweight and 15.7 % obese. The prevalence of SRBD was 13.4 %, more frequent among boys (15.7 % vs.10.9 %, p = 0.002) and in overweight/obese children (22.0 % vs.13.6 % vs.11.3 % in obese, overweight and normal weight group, respectively, p < 0.001). Children with SRBD had higher systolic BP (107 ± 8 vs.105±9 mmHg; p = 0.001) and lower HDL-cholesterol levels (54 ± 11 vs.56 ± 11 mg/dL; p = 0.04) than children without SRBD. After adjustment for sex, age, birthweight-for-gestational age and maternal age, children with SRBD had higher BMI-z-score, systolic BP, insulin and HOMA-IR levels, and lower HDL-cholesterol, when compared to those without SRBD, but these associations were lost when adjusting to BMI z-score. Analyzing obese children with the same regression model, those with SRBD presented lower HDL-cholesterol than those without SRBD.

CONCLUSIONS

Our results identified a male predominance of SRBD in pre-pubertal children and highlighted the potential contribution of SRBD to cardiovascular risk in obese children.

Diagnosis of Paediatric Obstructive Sleep-Disordered Breathing beyond Polysomnography

Obstructive sleep-disordered breathing (SDB) has significant impacts on health, and therefore, a timely and accurate diagnosis is crucial for effective management and intervention. This narrative review provides an overview of the current approaches utilised in the diagnosis of SDB in children. Diagnostic methods for SDB in children involve a combination of clinical assessment, medical history evaluation, questionnaires, and objective measurements. Polysomnography (PSG) is the diagnostic gold standard. It records activity of brain and tibial and submental muscles, heart rhythm, eye movements, oximetry, oronasal airflow, abdominal and chest movements, body position. Despite its accuracy, it is a time-consuming and expensive tool. Respiratory polygraphy instead monitors cardiorespiratory function without simultaneously assessing sleep and wakefulness; it is more affordable than PSG, but few paediatric studies compare these techniques and there is optional recommendation in children. Nocturnal oximetry is a simple and accessible exam that has high predictive value only for children at high risk. The daytime nap PSG, despite the advantage of shorter duration and lower costs, is not accurate for predicting SDB. Few paediatric data support the use of home testing during sleep. Finally, laboratory biomarkers and radiological findings are potentially useful hallmarks of SDB, but further investigations are needed to standardise their use in clinical practice.

Alternatives to Polysomnography for the Diagnosis of Pediatric Obstructive Sleep Apnea

Diagnosis of obstructive sleep apnea (OSA) in children with sleep-disordered breathing (SDB) requires hospital-based, overnight level I polysomnography (PSG). Obtaining a level I PSG can be challenging for children and their caregivers due to the costs, barriers to access, and associated discomfort. Less burdensome methods that approximate pediatric PSG data are needed. The goal of this review is to evaluate and discuss alternatives for evaluating pediatric SDB. To date, wearable devices, single-channel recordings, and home-based PSG have not been validated as suitable replacements for PSG. However, they may play a role in risk stratification or as screening tools for pediatric OSA. Further studies are needed to determine if the combined use of these metrics could predict OSA.

Patterns of Change in the Severity of Airway Obstruction with Robin Sequence in Early Infancy

Previous studies suggest that infants with Robin sequence show a pattern of steady improvement in the severity of airway obstruction, and of their treatment requirements, during infancy.

Methods

Three infants with Robin sequence and severe obstructive sleep apnea were managed with nasal continuous positive airways pressure (CPAP). Multiple measures of airway obstruction were made during infancy, including CPAP pressure evaluations and sleep studies (screening and polysomnography studies). Parameters reported include obstructive apnea-hypopnea index, oxygen desaturation parameters, and CPAP pressures required for effective airway management.

Results

CPAP pressure requirements increased in all three infants during their first weeks of life. Apnea indices on polysomnography did not track with the CPAP pressure requirements. Peak pressure requirements were at 5 and 7 weeks for two patients, with subsequent gradual decline and cessation of therapy CPAP at 39 and 74 weeks, respectively. The third patient had a complicated course, jaw distraction at 17 weeks, and biphasic CPAP pressure requirement (first peak at 3 weeks, but maximum pressure at 74 weeks), with cessation of CPAP at 75 weeks.

Conclusions

The observed pattern of early increases in CPAP pressure requirements for infants with Robin sequence adds to the complexities of managing this disorder. Factors that may lead to this pattern of change in airway obstruction are discussed.

Cardiovascular Disease in Obstructive Sleep Apnea: Putative Contributions of Mineralocorticoid Receptors

Obstructive sleep apnea (OSA) is a chronic and highly prevalent condition that is associated with oxidative stress, inflammation, and fibrosis, leading to endothelial dysfunction, arterial stiffness, and vascular insulin resistance, resulting in increased cardiovascular disease and overall mortality rates. To date, OSA remains vastly underdiagnosed and undertreated, with conventional treatments yielding relatively discouraging results for improving cardiovascular outcomes in OSA patients. As such, a better mechanistic understanding of OSA-associated cardiovascular disease (CVD) and the development of novel adjuvant therapeutic targets are critically needed. It is well-established that inappropriate mineralocorticoid receptor (MR) activation in cardiovascular tissues plays a causal role in a multitude of CVD states. Clinical studies and experimental models of OSA lead to increased secretion of the MR ligand aldosterone and excessive MR activation. Furthermore, MR activation has been associated with worsened OSA prognosis. Despite these documented relationships, there have been no studies exploring the causal involvement of MR signaling in OSA-associated CVD. Further, scarce clinical studies have exclusively assessed the beneficial role of MR antagonists for the treatment of systemic hypertension commonly associated with OSA. Here, we provide a comprehensive overview of overlapping mechanistic pathways recruited in the context of MR activation- and OSA-induced CVD and propose MR-targeted therapy as a potential avenue to abrogate the deleterious cardiovascular consequences of OSA.

Association of obstructive sleep apnea and total sleep time with health-related quality of life in children undergoing a routine polysomnography: a PROMIS approach

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) negatively impacts health-related quality of life (HR-QoL) in adults, but few pediatric studies have explored this relationship or the relationships between HR-QoL domains.

METHODS

Patients aged 8-17 years visiting the sleep laboratory from July 2019 to January 2020 for overnight polysomnography participated in the study. Controls seen for problems other than sleep disturbance were recruited from Department of Pediatrics outpatient clinics. HR-QoL was assessed by Patient-Reported Outcome Measure Information System (PROMIS) profile questionnaires, version 2.0. Statistical analysis was conducted using R 3.6.0 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

One hundred twenty-two patients were included in the final analysis. Sixty-four patients were males (52.4%). Twenty-nine (23.8%) had mild OSA, 8 (6.6%) had moderate OSA, 17 (13.9%) had severe OSA, 46 (37.7%) were without OSA, and 22 (18.0%) were controls. Patients referred for polysomnography had lower physical function mobility compared with controls (P = .03). Increased OSA severity was linearly associated with a decrease in physical function mobility (P = .008). Correlation analysis revealed that physical function mobility was positively associated with total sleep time (P = .02) and negatively associated with apnea-hypopnea index (P = .01). Age was positively associated with fatigue (P = .02) and negatively associated with deep sleep (P < .001). Regression analysis revealed that physical function mobility was positively associated with total sleep time (P = .02) and negatively associated with apnea-hypopnea index (P = .04) after controlling for age, sex, and number of arousals.

CONCLUSIONS

OSA and total sleep time were associated with problems with physical function mobility after adjusting for age, sex, and number of arousals.

CITATION

Xu S, Turakhia S, Miller M, et al. Association of obstructive sleep apnea and total sleep time with health-related quality of life in children undergoing a routine polysomnography: a PROMIS approach. J Clin Sleep Med. 2022;18(3):801-808.

You Cannot Hit Snooze on OSA: Sequelae of Pediatric Obstructive Sleep Apnea

Pediatric obstructive sleep apnea (OSA) has been shown to not only affect the quality of sleep, but also overall health in general. Untreated or inadequately treated OSA can lead to long-term sequelae involving cardiovascular, endothelial, metabolic, endocrine, neurocognitive, and psychological consequences. The physiological effects of pediatric OSA eventually become pathological. As the complex effects of pediatric OSA are discovered, they must be identified early so that healthcare providers can be better equipped to treat and even prevent them. Ultimately, adequate management of OSA improves overall quality of life.

WRISTOX2 is a reliable tool to diagnose obstructive sleep apnoea syndrome

INTRODUCTION

Overnight pulse oximetry is an alternative to polysomnography (PSG) in diagnosing obstructive sleep apnoea syndrome, but its sensitivity is reported to be low.

AIMS

To determine the (a) diagnostic accuracy, interobserver reliability and reliable oxygen desaturation index of 4% (ODI₄) score at diagnosing obstructive sleep apnoea syndrome in children and (b) correlation between the apnoea hypopnoea index (AHI) with ODI₄ and oxygen nadir between both PSG and oximetry.

METHODS

This cross-sectional study included children aged 1-18 years old, undergoing a fully attended overnight PSG for suspected obstructive sleep apnoea syndrome. The Nonin 3150 WristOx₂ ™ [Fig. 2] was worn simultaneously during the PSG. Poor oximetry recordings were excluded. Pulse oximetry was scored using the McGill Oximetry Score (MOS) whereby a score of 2-4 was positive for OSAS. Specificity, sensitivity, positive predictive values (PPV), negative predictive values (NPV) and interobserver reliability of the WristOx₂ were calculated.

RESULTS

One hundred and sixty-two children with a mean (SD) age of 9.3 (±3.5) years (range 2 years 6 months old - 17 years old) were included after excluding 18 children (poor oximetry data [n = 16] and incomplete PSG [n = 2]). Interobserver agreement of the WristOx₂ was 0.8763 (95% CI:0.80, 0.95). WristOx₂ had a sensitivity 50%, specificity 96.7%, PPV 96% and NPV 53% at diagnosing OSAS. ODI₄ ≥ 2 events/hour in oximetry had a sensitivity of 97.6% and negative predictive value of 85.7% at diagnosing OSA.

CONCLUSION

Overnight pulse oximetry with the Nonin 3150 WristOx₂ ™ is an accurate and reliable tool in diagnosing significant OSAS in children.

Cardiovascular changes in children with obstructive sleep apnea and obesity after treatment with noninvasive ventilation

STUDY OBJECTIVES

Adults with obesity and obstructive sleep apnea (OSA) are at risk for cardiometabolic disease, and this risk likely extends to children with both conditions. Noninvasive ventilation (NIV; including continuous and bilevel positive airway pressure) is often used to treat OSA in children with obesity. The aim of this study was to examine the impact of NIV treatment on heart rate variability (HRV), as a marker of cardiovascular risk, in children with obesity and newly diagnosed OSA.

METHODS

A prospective multicenter cohort study was conducted in children with obesity prescribed NIV therapy for newly diagnosed moderate-severe OSA. Measurements of HRV were derived from polysomnography recordings at baseline and after 12 months of treatment. HRV parameters were examined by sleep stage, before and after arousal and oxygen desaturation events. HRV parameters were compared between time points using pair t tests as well as mixed model analysis.

RESULTS

Twelve children had appropriate data for analysis at baseline and 12 months. Heart rate decreased by 4.5 beats/min after NIV treatment, with no change in HRV parameters. HRV parameters differed by sleep stage and showed an increase in arousal-related sympathetic-parasympathetic balance after 12 months of NIV treatment. HRV parameters did not differ before and after oxygen desaturation events.

CONCLUSIONS

NIV for the treatment in children with obesity and OSA resulted in a small decrease in heart rate and an increase in arousal-related sympathetic-parasympathetic balance. These findings suggest small, potentially positive impacts of NIV on cardiovascular risk in children with concurrent obesity and OSA.

Obstructive sleep apnea and insulin resistance in children with obesity

STUDY OBJECTIVES

Because existing data investigating obstructive sleep apnea (OSA) and insulin resistance (IR) are inconsistent, we examine OSA and IR in a pediatric obesity clinic.

METHODS

Children (2-18 years) in the obesity clinic (2013-2017) undergoing polysomnography (PSG), anthropometric measurements, and fasting laboratory tests were included. Linear regression assessed OSA defined by the obstructive apnea-hypopnea index (oAHI) with the homeostatic model assessment of insulin resistance (HOMA-IR). Secondary aims assessed oxygen desaturation index (ODI) and age interactions with HOMA-IR. Logistic regression models and receiver operating characteristic analysis were performed to investigate optimal oAHI and ODI cutoffs relative to HOMA-IR ≥ 3.

RESULTS

Eighty children were included (mean age, 11.4 ± 4.0 years; 56% female; 46% Caucasian; median body mass index [BMI], 34.6 kg/m² [interquartile ratio, 29.9-40.1], median BMI z-score, 2.5 [interquartile ratio, 2.3-2.8); 46% with oAHI ≥ 5 events/h. HOMA-IR was higher in the OSA group (oAHI ≥ 5 events/h): 5 vs 3.8 (P = .034). After adjustment for sex, race, and BMI z-score, oAHI ≥ 5 events/h retained significance with HOMA-IR (P = .041). HOMA-IR increased in older children (age ≥ 12 years) when adjusting for waist circumference z-score and waist-height ratio (statistical interaction, P = .020 and .034, respectively). Receiver operating characteristic showed optimal cut points of oAHI and ODI for predicting significant IR 4.9 (area under the curve, 0.70; 95% confidence interval, 0.57-0.83; sensitivity, 0.76; specificity, 0.66) and 4.6 (area under the curve, 0.68; 95% confidence interval, 0.55-0.80; sensitivity, 0.70; specificity, 0.67), respectively.

CONCLUSIONS

In a clinic-based pediatric cohort with obesity, OSA is associated with increased IR even after adjusting for confounders including obesity defined by the BMI z-score. Age ≥ 12 years was associated with AHI relative to IR after adjustment for waist circumference z-score and waist-height ratio. Significant IR could be discriminated by oAHI ≥ 4.9 with moderate sensitivity/specificity. Future studies are needed to verify these findings.

Identification of different clinical faces of obstructive sleep apnea in children

OBJECTIVE

This study aimed to identify the heterogeneity of obstructive sleep apnea syndrome clinical presentation in children.

PARTICIPANTS

Children who were 3-14 years old and with obstructive sleep apnea syndrome after polysomnography monitoring (apnea and hypopnea index>5 or obstructive apnea index>1) in the sleep center of Beijing Children's Hospital were included.

METHODS

A sleep disorder questionnaire including different combinations of symptoms and co-morbidities of obstructive sleep apnea syndrome in children was used. A cluster analysis was used to classify the data.

RESULTS

The apnea hypopnea index alone is not adequate to predict clinical phenotypes. Based on symptoms and co-morbidities of obstructive sleep apnea syndrome, three distinct clusters were identified. They were "nocturnal snoring and daytime sleepiness group" (cluster 1), "hyperactivity group" (cluster 2), and "minimally symptomatic group" (cluster 3). A prediction model was built according to eight variables which showed statistical significance by pairwise comparison among clusters. Overall accuracy of the prediction model could reach 86%. Both the sensitivity and specificity of cluster 2 and 3 prediction were around 90%.

CONCLUSION

Children with obstructive sleep apnea syndrome have different patterns of clinical presentation and the identification of the different clinical profiles of obstructive sleep apnea syndrome can provide clues for more personalised diagnoses and therapies.

Study of Sleep Disorders among Young Children Using Hindi Translated and Validated Version of Pediatric Sleep Questionnaire

OBJECTIVE

The objective of this study is to assess the prevalence of sleep disorders among children aging between 4 and 9 years using Hindi version of Pediatric Sleep Questionnaire (PSQ).

METHODS

This study had two parts first, translation and validation of PSQ into Hindi language, and second, assessment of the prevalence of sleep disorders using PSQ Hindi version. Hindi PSQ was distributed in randomly chosen primary schools in a semi-urban area. The children were requested to get them filled by their parents. When the questionnaires were returned, responses were analyzed.

RESULTS

Most of the items of the Hindi version had perfect agreement with original questionnaire in a bilingual population (κ =1). Totally, 435 children were included in the field study having average age of 6.3 years. Obstructive sleep apnea was reported in 7.5% children; symptoms suggestive of restless legs syndrome were reported by 2%-3%; teeth grinding by 13.9% and sleep talking by 22.6% children.

CONCLUSION

PSQ Hindi version is a validated tool to screen for sleep disorders among children. Sleep disorders are fairly prevalent among young children in India.

Cardiometabolic correlates of sleep-disordered breathing in renal transplant children

Sleep-disordered breathing, a prevalent condition among adult renal transplant (RTx) recipients, has become an established independent risk factor of MetS, and furthermore, it might contribute to increased CV risk. Despite the proven correlations in adults, there is a lack of evidence for its significance in the pediatric RTx population. In this study, we aimed at assessing the prevalence and the clinical correlates of SDB in RTx children. Data of 13 patients (age [mean ± SD]: 14.2 ± 2.7 years) were analyzed. SDB was evaluated by PSG, as severity score OAHI was applied. Carbohydrate metabolism was characterized by OGTT, whereas CV status was studied by ABPM. Three composite end-points were calculated as sum of z-scores: daytime systolic and diastolic BP; nighttime systolic and diastolic BP; and glucose and insulin levels at 120 minutes. Eight patients (61.5%) were diagnosed with SDB of whom five patients (38.5%) had moderate or severe SDB. In linear regression analysis, OAHI during REM was associated with the CV variables (daytime BP P = 0.032, ß = 0.748; nighttime BP P = 0.041, ß = 0.715), and the correlations remained significant after adjustments for BMI. However, we did not confirm a significant association with the metabolic variables. The prevalence of SDB was high, and its severity during REM was a predictor of the BP suggesting that RTx children with SDB might be at risk of developing CV complications, especially HTN similarly to adults.

Does Tonsillectomy Increase Obesity Risk in Children with Down Syndrome?

OBJECTIVES

To examine weight changes relative to surgical success in children with Down syndrome and obstructive sleep apnea (OSA).

STUDY DESIGN

Retrospective chart review of children with Down syndrome undergoing tonsillectomy from 2005 to 2016 for OSA at a tertiary care children's hospital. Only patients with pre-and postoperative polysomnogram within 6 months of tonsillectomy were included. Demographics, weight, height, and polysomnogram data were collected. Body mass index (BMI), expressed as a percentage of the 95th percentile (%BMI_p95), was calculated for 24 months prior to and following surgery. Pre-and postoperative OSA severity were also recorded. The postoperative obstructive/hypopnea index identified subjects with resolution of obstruction (obstructive/hypopnea index <2 events/hour) or persistent mild/moderate/severe obstructive apnea. Regression analyses were used to compare %BMI_p95 pre- and post-tonsillectomy with %BMI_p95 by OSA status following tonsillectomy.

RESULTS

A total of 78 patients with Down syndrome whose mean age was 5.29 years at time of tonsillectomy were identified. There was no difference between best-fit curves of %BMI _p95 pre-and post-tonsillectomy. There was no difference between best-fit curves of %BMI _p95 in patients who saw resolution of OSA after tonsillectomy vs patients with residual OSA.

CONCLUSIONS

Tonsillectomy neither alters the BMI trajectory of children with Down syndrome, nor changes differentially the risk for obesity in children whose OSA did or did not resolve after surgery.

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea

STUDY OBJECTIVES

Current evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.

METHODS

Twenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.

RESULTS

Baseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.

CONCLUSIONS

These findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present.

Association of sleep disturbances with obesity, insulin resistance and the metabolic syndrome

Insufficient sleep, which has become endemic in recent years, has been variably associated with increased risk of obesity, disorders of glucose and insulin homeostasis, and the metabolic syndrome; to a lesser degree, so has excessive sleep. This review summarizes recent epidemiological and pathophysiological evidence linking sleep disturbances (primarily abnormalities of sleep duration) with obesity, insulin resistance, type 2 diabetes and the metabolic syndrome in children and adults.

The scope of sleep problems in Canadian children and adolescents with obesity

OBJECTIVE

To determine the scope of sleep concerns, clinical features, and polysomnography (PSG) results and to identify factors that predict obstructive sleep apnea (OSA) in a cohort of children with obesity.

METHODS

The study was a multicenter retrospective chart review. Data were collected from three pediatric sleep laboratories over a two year period for all children of age 8-16 years with a body mass index [BMI] ≥95th centile who were undergoing PSG. Data sources included clinical charts and PSG results. Clinical and PSG factors were examined as predictors of OSA.

RESULTS

A total of 210 children met inclusion criteria, and 205 had sufficient data for analysis. The mean age was 12.5 ± 2.7 years; and 65% were male. Multiple sleep concerns and comorbidities were reported in most children (90% and 91%, respectively). OSA was identified by PSG in 44% of children; and 28% of children demonstrated moderate/severe OSA. Mouth breathing/nasal congestion (odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.18-0.61), syndrome/multiple anomalies (OR = 2.4, 95% CI = 1.22-4.93), and family history of OSA (OR = 2.7, 95% CI = 1.2-5.8) or sleep problems (OR = 12.4, 95% CI = 1.5, 99.6) were the only factors predictive of OSA. Oxygen desaturation index <6 events/h measured by PSG showed an OR of 4.96 (95% CI = 2.27-10.86) for the absence of OSA.

CONCLUSIONS

Children with obesity who undergo PSG are medically complex with multiple sleep concerns including a high burden of daytime symptoms; slightly less than half of children demonstrate polysomnographic features of OSA. Earlier identification of OSA, recognition of non-OSA sleep concerns, and treatment strategies to improve sleep may contribute to overall health outcomes for children with obesity.

Pediatric sleep-disordered breathing: an update on diagnostic testing

PURPOSE OF REVIEW

Recent advances in diagnostic testing for obstructive sleep apnea in children have refined the standard tests while identifying several new tools that hold promise to radically change how we diagnose sleep apnea.

RECENT FINDINGS

Studies have demonstrated that the polysomnogram may be modified to permit home assessment of sleep disturbed breathing in children to ensure more widespread access to the test. Alternately, questionnaires, nocturnal oximetry, and diagnostic urinary biomarkers have shown great promise as both sensitive and specific tools to diagnose sleep apnea in children as well as track the severity of the disease.

SUMMARY

The gold standard polysomnogram has been refined to permit its application in a modified form at home and for brief examinations in children. This standard has been challenged on several fronts, including questionnaires, nocturnal oximetry, drug-induced sleep endoscopy, and noninvasive urinary biomarkers that may ultimately supplant polysomnography as the gold standard to diagnose obstructive sleep apnea syndrome in children.

Characteristics of Obstructive Sleep Apnea Across the Spectrum of Glucose Tolerance in Obese Adolescents

BACKGROUND

It is not known if dysglycemia and sleep-disordered breathing are linked in adolescents, as in adults.

OBJECTIVE

To perform a pilot study evaluating measures of sleep-disordered breathing across the spectrum of glucose tolerance in obese adolescents. We hypothesized that dysglycemia would be associated with sleep-disordered breathing.

PARTICIPANTS/METHODS

This was a prospective, cross-sectional clinical pilot study that included 57 adolescents [body mass index (BMI) 38.9 ± 8.4 kg/m²] aged 12-18 years (14.5 ± 1.6) with normal glucose tolerance (NGT), or dysglycemia [impaired glucose tolerance (IGT) or type 2 diabetes (T2D)].

MEASURES

Anthropometrics, overnight polysomnogram, and oral glucose tolerance tests were performed. Participant characteristics and outcome measures were compared by glucose tolerance status. Correlational analyses were conducted to assess the associations between variables of interest.

RESULTS

Participants with dysglycemia (n = 21) were not different from those with NGT (n = 36) for BMI, waist circumference, body fat, or sleep characteristics. Nocturnal oxygen desaturation was associated with higher BMI (r = -0.334, p = 0.012). The apnea-hypopnea index (AHI) was not associated with physical and metabolic parameters. Although participants with dysglycemia tended to have higher AHIs (median 3.2, 2.2, and 1.6 events/h for T2D, IGT, and NGT, respectively), there was not a linear relationship between measures of glycemia and AHI.

CONCLUSION

Further study with a larger proportion of youth with prediabetes and T2D is necessary to determine whether evaluation for sleep-disordered breathing is uniformly warranted.

Poor Sleep and Obesity: Concurrent Epidemics in Adolescent Youth

Poor sleep and obesity are both extraordinarily common in the US adolescent population and often occur simultaneously. This review explores the links between obesity and sleep, outlining what is known about the relationships between sleep characteristics, obesity, and cardiometabolic risk factors in youth. Sleep duration is less than optimal in teens, and decreases as age increases. This is detrimental to overall well-being and is associated with obesity in children, adolescents, and young adults. Accordingly, inadequate sleep duration is associated with poor diet quality, decreased insulin sensitivity, hyperglycemia, and prevalent cardiometabolic risk factors. Evidence suggests that poor sleep quality and altered circadian timing characterized by a preferred later sleep onset, known as "adolescent chronotype," contributes to shortened sleep duration. Obstructive sleep apnea (OSA) occurs more frequently among youth with obesity, and is associated with autonomic nervous system activity promoting higher blood pressure, increased markers of cardiovascular disease risk, and insulin resistance. While there is a clear association between OSA and type 2 diabetes in adults, whether or not this association is prevalent in youth is unclear at this time. Interventions to improve both sleep duration and quality, and obesity in adolescents are scarce and more evidence is needed to determine if such interventions can improve obesity-related health outcomes.

Insulin Resistance and Hypertension in Obese Youth With Sleep-Disordered Breathing Treated With Positive Airway Pressure: A Prospective Multicenter Study

STUDY OBJECTIVES

There is evidence that cardiometabolic disease associated with obesity and sleep-disordered breathing (SDB) in adults is present in youth. SDB is often treated with positive airway pressure (PAP) in youth with obesity. Our aims were to determine: (1) the prevalence of cardiometabolic disease and (2) whether PAP improves markers of cardiometabolic disease, in youth with obesity and newly diagnosed moderate-severe SDB.

METHODS

A prospective multicenter cohort study was conducted in youth (8 to 16 years old) with obesity, prescribed PAP therapy for newly diagnosed moderate-severe SDB. Assessments occurred at baseline and at 6 and 12 months. Outcomes included markers of insulin resistance (change in homeostasis model assessment of insulin resistance (HOMA-IR) at 6 months = primary outcome), hypertension (24-hour ambulatory/blood pressure) and inflammation (high-sensitivity C-reactive protein: hs-CRP).

RESULTS

Twenty-seven participants were enrolled. Of those with baseline testing available, 10/25 (40%) had HOMA-IR above the 97th percentile, 10/23 (44%) were hypertensive, 16/23 (70%) had loss of nocturnal blood pressure dip and hs-CRP was elevated in 16/27 (64%). There were no significant changes over time in markers of metabolic dysfunction or blood pressure, nor between PAP-adherent and non-adherent subgroups.

CONCLUSIONS

In youth with obesity and SDB, metabolic dysfunction and hypertension were highly prevalent. There were no statistically significant improvements in cardiometabolic markers 1 year after the prescription of PAP therapy, although clinically relevant improvements were seen in insulin resistance and systolic blood pressure load, important predictors of future risk of cardiovascular disease. Larger, longer-term studies are needed to determine whether PAP improves cardiometabolic outcomes in obese youth.

COMMENTARY

A commentary on this article appears in this issue on page 1025.

Clinical symptoms that predict the presence of Obstructive Sleep Apnea

OBJECTIVE

To determine if a set of clinical symptoms can help in determining the presence and severity of OSA.

SETTING

Tertiary urban pediatric hospital.

METHODS

Parents of children undergoing an overnight PSG answered a 56 item questionnaire based on their child's symptoms. The responses to the questionnaire were compared between patients with different severities of OSA (s determined by PSG) and those without OSA. Responses to questionnaire were also analyzed between obese and non-obese patients.

RESULTS

235 children were included (140 male and 95 female) with a mean age of 5.76 ± 2.78 years. The mean Apnea Hypopnea Index (AHI) was 7.78 ± 14.50 events/hour (range 0-110 events/h). 74 (31.5%) children had mild-OSA (AHI between 1 and 4.99 events/h), 31 (13.19%) had moderate-OSA (AHI between 5 and 9.99 events/h), 58 (24.7%) had severe-OSA (AHI≥10events/h) and the remaining 72 (30.64%) had No-OSA (AHI≤1event/h). 87 (37%) patients were obese. Eight clinical symptoms in non-obese and six clinical symptoms in obese patients predicted the mild to severe OSA. Sixteen symptoms in non-obese patients and nine symptoms in obese patients predicted the presence of severe OSA in these patients.

CONCLUSION

Clinical symptoms reported in this study are useful to predict the presence of and the severity of OSA in children. Clinical symptoms can also predict the presence and severity of OSA in children who are obese, however, the symptoms required to make the prediction are different in obese children.

Pediatric OSA Syndrome Morbidity Biomarkers: The Hunt Is Finally On!

Since initial reports 40 years ago on pediatric OSA syndrome (OSAS) as a distinct and prevalent clinical entity, substantial advances have occurred in the delineation of diagnostic and treatment approaches. However, despite emerging and compelling evidence that OSAS increases the risk for cognitive, cardiovascular, and metabolic end-organ morbidities, routine assessment of such morbidities is seldom conducted in clinical practice. One of the major reasons for such discrepancies resides in the relatively labor-intensive and onerous steps that would be required to detect the presence of any of such morbidities, further adding to the already elevated cost of diagnosing the disorder. To circumvent these obstacles, the search for biomarker signatures of pediatric OSA and its cognitive and cardiometabolic consequences was launched, and considerable progress has occurred since then. Here, we review the current evidence for the presence of morbidity-related biomarkers among children with OSAS, and explore future opportunities in this promising arena.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.

Consequences of Obstructive Sleep Apnea in Children

Obstructive sleep apnea syndrome (OSAS) has various negative health and behavioral consequences in the pediatric population. As shown in adults, there are metabolic derangements such as obesity, insulin sensitivity, dyslipidemia, and metabolic syndrome, as well as cardiovascular derangements like hypertension, chronic inflammation, endothelial dysfunction, ventricular size/function abnormalities, and even elevated pulmonary arterial pressures, that can be seen in children with OSAS. The first two sections will discuss the metabolic and cardiovascular consequences on OSAS in children. The last section summarizes selected studies and reviews on the behavioral, neurocognitive and academic consequences of OSAS in children.

Metabolic alterations in adolescents with obstructive sleep apnea

IMPORTANCE

Obesity is one of the leading health concerns in developed and in developing countries. The risk of obstructive sleep apnea (OSA) is greatly increased by obesity. Obesity is known to be associated with the Metabolic Syndrome and cardiovascular disease in adults. This same association in children is not well defined. Understanding the relationship of obesity, OSA, and metabolic alterations in children would improve understanding of the risks of cardiovascular disease into adulthood.

OBJECTIVE

To evaluate the association of OSA and metabolic outcomes, including lipid variables and insulin resistance, in obese adolescents.

METHODS

Retrospective, case-control series at a tertiary care children's hospital. Obese adolescents aged 12-18 years who underwent overnight polysomnography (PSG) and routine laboratory testing for lipid levels, fasting glucose, and insulin from January 1, 2006 to December 31, 2012.

RESULTS

A total of 42 patients with a mean age of 14.1±1.9 years were analyzed. Nineteen (45.2%) were male. The mean body mass index (BMI) z score was 2.23±0.86, and all patients were obese (BMI z score >95th percentile). Triglyceride, fasting blood glucose, insulin, and homeostasis model assessment-insulin resistance (HOMA-IR) levels were significantly higher in patients with OSA when compared to those with No-OSA (p<0.01). There was incremental worsening of insulin and HOMA-IR with greater severity of OSA. The apnea-hypopnea index (AHI) was positively and significantly correlated with blood glucose and HOMA-IR (p=0.01and p<0.001, respectively). Multiple linear regression analysis showed that the AHI was a predictor of blood glucose (p=0.04) and HOMA-IR (p=0.01) independent of age, gender, total sleep time and BMI z score. Logistic regression analysis showed that elevated levels of blood glucose predicted severe OSA (p=0.02) independent of gender and BMI z score. Elevation in HOMA-IR predicted severe OSA (p=0.004).

CONCLUSION

OSA severity is associated with increased fasting insulin, blood glucose and HOMA-IR even after controlling for the age, and BMI z score in adolescents.

Polysomnography for the diagnosis of sleep disordered breathing in children under 2 years of age

OBJECTIVES

To describe clinical polysomnography (PSG) results, sleep physicians' diagnosis, and treatment of sleep disorder breathing in children less than 2 years of age.

STUDY DESIGN

Retrospective clinical chart review at a pediatric tertiary care center, pediatric sleep laboratory.

SUBJECT SELECTION

Children less than 2 years of age who underwent clinical PSG over a 3-year period.

METHODOLOGY

PSG results and physician interpretations were identified for inclusions. Children were excluded if either PSG results or physician interpretations were unavailable for review. Infants were classified in three age groups for comparison: <6 months, 6-12 months, and >12 months.

RESULTS

Matched records were available for 233 PSGs undertaken at a mean age 11.1 ± 7.0 months; 31% were <6 months, 23% were 6-12 months, and 46% were 12-24 months of age. Infants <6 months showed significant differences on sleep parameters and respiratory indicators compared to other groups. Compared to physician sleep disordered breathing (SDB) classification, current pediatric apnea-hypopnea index (AHI)-based SDB severity classification overestimated SDB severity. Age and obstructive-mixed AHI (OMAHI) were most closely associated with physician identification of SDB.

CONCLUSION

Children <6 months of age appear to represent a distinct group with respect to PSG. Experienced sleep physicians appear to incorporate age and respiratory event frequently when determining the presence of SDB. Further information about clinical significance of apnea in infancy is required, assisted by identification of factors that sleep physicians use to identify SDB in children <6 months of age.

Metabolic and glycemic sequelae of sleep disturbances in children and adults

The prevalence of obesity in adults and children has increased greatly in the past three decades, as have metabolic sequelae, such as insulin resistance and type 2 diabetes mellitus (T2DM). Sleep disturbances are increasingly recognized as contributors to this widespread epidemic in adults, and data are emerging in children as well. The categories of sleep disturbances that contribute to obesity and its glycemic co-morbidities include the following: (1) alterations of sleep duration, chronic sleep restriction and excessive sleep; (2) alterations in sleep architecture; (3) sleep fragmentation; (4) circadian rhythm disorders and disruption (i.e., shift work); and (5) obstructive sleep apnea. This article reviews current evidence supporting the contributions that these sleep disorders play in the development of obesity, insulin resistance, and T2DM as well as possibly influences on glycemic control in type 1 diabetes, with a special focus on data in pediatric populations.