Autonomic alterations and endothelial dysfunction in pediatric obstructive sleep apnea

Impact of obstructive sleep apnea in cardiovascular risk in the pediatric population: A systematic review

While the association of obstructive sleep apnea (OSA) with an increased cardiovascular risk (CVR) in the adult population is well known, there is insufficient evidence to affirm something similar in the pediatric population. On the other hand, adenotonsillectomy has been shown to be an effective treatment. Our objective was to evaluate the association of sleep respiratory disorders in children with increased CVR and the impact of adenotonsillectomy in the literature. To this aim, a literature search was conducted, between 2002 to the present. After carrying out a systematic review, the following results were provided: thoracic echocardiography after surgery found improvements in terms of cardiac function and structure; blood pressure (BP) measurement, verified a tendency to higher BP values in the OSA pediatric population, which improved after surgery; different biomarkers of CVR, were increased in OSA patients and improved after treatment and finally; some studies found endothelial dysfunction in pediatric OSA, a measurement of vascular system function, was reversible with adenotonsillectomy. Increases in BP parameters, biological markers related to CVR and alterations in cardiac function structure, have been reported in pediatric patients with OSA. At least, some of these parameters would be reversible after adenotonsillectomy, reflecting a possible reduction in CVR.

An Obstructive Sleep Apnea - A Novel Public Health Threat

In patients with obstructive sleep apnea (OSA) during obstructive events, episodes of hypoxia and hypercapnia may modulate the autonomic nervous system (ANS) by increasing sympathetic tone and irritability, which contributes to sympathovagal imbalance and ultimately dysautonomia. Because OSA can alter ANS function through biochemical changes, we can assume that heart rate variability (HRV) will be altered in patients with OSA. Most studies show that in both the time and frequency domains, patients with OSA have higher sympathetic components and lower parasympathetic dominance than healthy controls. These results confirm autonomic dysfunction in these patients, but also provide new therapeutic directions. Respiratory methods that modulate ANS, e.g., cardiorespiratory biofeedback, could be beneficial for these patients. Heart rate variability assessment can be used as a tool to evaluate the effectiveness of OSA treatment due to its association with autonomic impairment.

Level of urinary catecholamine in children with Sleep Disordered Breathing: A systematic review and meta-analysis

OBJECTIVE

To compare the levels of different urinary catecholamines amongst paediatric patients with and without sleep-disordered breathing (SDB).

METHODS

Literature searches were conducted on PubMed and EMBASE until 25/06/2022. Inclusion criteria were original human studies, English language, paediatric subjects diagnosed with SDB/obstructive sleep apnoea (OSA). The quality of studies was assessed by the Newcastle-Ottawa Quality Assessment (NOSGEN). The registered number of this study on the International Prospective Register of Systematic Reviews (PROSPERO) is CRD42022332939. The main outcome measured was standardised mean difference (SMD) of urinary catecholamine between subjects with and without SDB, between those with and without OSA, and also between subjects with mild OSA and those with moderate/ severe OSA. Sensitivity analyses were performed to avoid bias.

RESULTS

9 studies (8 cross-sectional and 1 cohort study) with a total of 838 subjects, were included in the quantitative analysis. Urine level of noradrenaline was higher in patients with SDB, which included primary snoring (PS), when compared to controls: SMD = 0.86 (95%CI=0.32-1.41; I²=85%, P=0.002). The levels of urinary noradrenaline and adrenaline were higher in children with OSA when compared to controls: SMD = 1.45 (95%CI=0.91-2.00; I²=75%, P < 0.001); SMD = 1.84 (0.00-3.67; I²=97%, P=0.05). Urine level of noradrenaline was higher in subjects with moderate/severe OSA compared to the mild OSA: SMD = 0.55 (95%CI=0.10-1.00; I²=0%, P=0.02). Urinary dopamine was not associated with SDB regardless of severity.

CONCLUSIONS

Urinary noradrenaline was higher in all patients with SDB. Subjects with OSA, a more severe form of SDB, had higher urine levels of noradrenaline and adrenaline. Hence, noradrenaline and adrenaline may be markers of sympathetic overtone in patients with SDB and could potentially act as surrogate markers for SDB complications. Further studies are needed to assess this association.

[Diagnostic criteria for obstructive sleep apnea syndrome in adolescent]

The obstructive sleep apnoea syndrome (OSAS) affects 1-4% of adolescents. It represents a transitional stage between paediatric and adult OSA and is characterized by specific symptoms. BACKGROUND: The persistence of childhood OSAS during adolescence is not frequent. Risk factors are male sex, obesity and a history of tonsillectomy or adenoidectomy. Symptoms may be misleading such as tiredness and depressive disorders. In adolescence, untreated OSAS may result in neuro-behavioural and cognitive deficits, systemic inflammation, cardiovascular and metabolic disorders. The French Society of Research and Sleep Medicine organized a meeting on OSAS in adolescents. A multidisciplinary group of specialists (pulmonologists, pediatricians, ENT and maxillo-facial surgeons, dentofacial orthopedists/orthodontists, myofunctional therapists and sleep specialists) exchanged their experience, discussed publications and drew up a consensus document on the diagnosis and polysomnographic criteria for OSAS in adolescents. They proposed a practical diagnostic guideline and follow-up for these adolescents. OUTLOOK AND CONCLUSION: A good knowledge of the particularities of this pathology by the physician will lead to an early diagnosis, propose adapted multifactorial treatments and avoid the deleterious consequences of this pathology at adult age.

Attenuated heart rate recovery in children and adolescents with obstructive sleep apnea syndrome

BACKGROUND

Autonomic dysfunction is a key trait in the development of obstructive sleep apnea syndrome (OSAS) in adults. However, few similar studies focused on children and adolescents. We investigated if there was any association between heart rate recovery (HRR) and the severity of OSAS in children and adolescents.

METHODS

A total of 161 subjects were included: 87 healthy controls, 35 mild OSAS patients (M-OSAS) and 39 moderate-severe OSAS (M-S-OSAS) patients. Clinical parameters, cardiopulmonary exercise test (CPET) indexes including HRR and polysomnographic records including apnea-hypopnea index (AHI) were compared among the three groups. Pearson correlation analysis and multivariable linear regression analysis were used to detect the relationship between HRR and polysomnographic parameters.

RESULTS

HRR values in either the OSAS group were lower than those of the control group, and the values in the M-S OSAS group were even lower than those of the M-OSAS group (P < 0.05). Correlation analysis showed that HRR was inversely correlated with AHI (r = -0.190, P < 0.01). Moreover, multivariable linear regression analyses showed the association between HRR and AHI was significant (β = 0.174, P < 0.01).

CONCLUSIONS

HRR was closely associated with OSAS severity, which suggested that HRR might be a promising index for risk stratification and clinical management in children and adolescents with OSAS.

IMPACT

Heart rate recovery (HRR), a noninvasive and reliable index of automatic nervous system, is closely associated with the severity of obstructive sleep apnea syndrome (OSAS) in children and adolescents. To our knowledge, our study was the first study in China focusing on evaluating the role of HRR in children with OSAS. We found HRR was closely associated with OSAS severity in children and adolescents, and it suggested that HRR might be a promising index for risk stratification and clinical management in children and adolescents with OSAS.

Tim-3 is a potential regulator that inhibits monocyte inflammation in response to intermittent hypoxia in children with obstructive sleep apnea syndrome

The mechanism of the characteristic intermittent hypoxia (IH) of obstructive sleep apnea syndrome (OSAS) on monocyte remain unclear. Our study found that OSAS children had a significantly upregulated expression in circulating proinflammatory cytokines IL-6 and IL-12, and endothelial injury markers VEGF and ICAM1. Association analysis revealed that the plasma TNFα, IL-1β, IL-6, IL-10 and IL-12 concentration were negatively associated with the minimal SpO₂, a negative index for disease severity. OSAS monocytes presented an inflammatory phenotype with higher mRNA levels of inflammatory cytokines. Importantly, we noted a significant decrease in T-cell immunoglobulin and mucin domain (Tim)-3 expression in OSAS monocytes with the increase of the plasma proinflammatory cytokines. In vitro assay demonstrated that IH induced THP-1 cell overactivation via NF-κB dependent pathway was inhibited by the Tim-3 signal. Our results indicated that activation of monocyte inflammatory responses is closely related to OSAS-induced IH, and negatively mediated by a Tim-3 signaling pathway.

The efficacy of different treatment approaches for pediatric OSAHS patients with mandibular retrognathia: study protocol for a multicenter randomized controlled trial

Background

Pediatric obstructive sleep apnea/hypopnea syndrome (OSAHS) is a multifactorial syndrome caused by many risk factors, such as craniofacial anomalies, adenotonsillar hypertrophy, obesity, and airway inflammation. Although new treatment patterns have recently been proposed, treatment methods for children remain particularly challenging and controversial. This randomized controlled trial was designed to investigate the efficacy of adenotonsillectomy and/or orthodontic treatment for children who have mild OSAHS with mandibular retrognathia.

Methods

A sample of 352 children with mild OSAHS and mandibular retrognathia, who are aged between 7 and 10 years, will be enrolled in the study. They will be randomized into four groups: the drug treatment group, the surgical treatment group, the orthodontic treatment group, or the surgery and postoperative orthodontic group. After randomization the children will receive treatments within 4 weeks. Outcome assessment will take place at the following points: (1) baseline, (2) 7 months after the treatment starting point, (3) 12 months after the treatment starting point, and (4) 24 months after the treatment starting point. The primary endpoint of the trial is the mean change in obstructive apnea/hypopnea index. Other endpoints will consist of the lowest oxygen saturation, apnea index, and hypopnea index assessed by polysomnography, subjective symptoms (assessed by the OSA-20 questionnaire), cephalometric measurements, and morphologic analysis of the upper airway.

Discussion

The results of this study will provide valuable evidence for the merits and long-term efficacy of different treatment approaches and contribute to facilitating the multidisciplinary treatment of pediatric OSAHS.

Trial registration

ClinicalTrials.gov: NCT03451318. Registered on 2 March 2018 (last update posted 19 April 2018).

Associations of sleep quality, sleep apnea and autonomic function with insulin secretion and sensitivity: HSCAA study

RATIONALE AND PURPOSE

Although sleep disorders are shown to be involved in occurrence of diabetes, impacts of several quantitative parameters related to sleep on insulin secretion and sensitivity is yet to be elucidated. We cross-sectionally examined relationships among quantitative sleep quality, sleep apnea, and autonomic function with insulin secretion and sensitivity in 399 patients without previous diagnosed diabetes who underwent 75-g oral glucose tolerance test (75gOGTT).

METHOD

Poor sleep quality (PSQ) was defined as an activity index ≥50 by actigraphy. Sleep apnea was measured by apnomonitor, while standard deviation of all normal-to-normal R-R intervals (SDNN) was measured by active tracer. Parameters of insulin secretion and sensitivity were measured by 75gOGTT.

RESULTS

Patients with PSQ exhibited significantly lower insulinogenic index (r = 0.155, p < 0.01), a parameter of insulin secretion, with the association independent of other clinical factors including apnea and SDNN (β = -0.156, p < 0.01). In contrast, presence of sleep apnea (r = -0.143, p < 0.05) and the lower SDNN (r = -0.150, p < 0.01) were significantly and inversely associated with BIGTT-S, an insulin sensitivity parameter, with the association of SDNN with BIGTT-S remaining significant even after adjustments for PSQ and sleep apnea (β = -0.111, p < 0.05).

CONCLUSION

Poor sleep quality is an independent predictor of pancreatic β-cell function, which could be involved in occurrence of type 2 diabetes.

The cardiovascular risk in paediatrics: the paradigm of the obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) describes a spectrum of abnormal breathing patterns during sleep characterised by snoring, increased upper airway resistance and pharyngeal collapsibility, with alteration of normal oxygenation and ventilation. Intermittent desaturations during sleep have multi-organ implications. Adults with OSAS have an increased risk of developing a dysfunctional endothelium that is characterised by greater adherence of inflammatory mediators to endothelial cells and hypercoagulability. There is increasing evidence to show that risk factors for comorbid cardiovascular disease (CVD) can develop during childhood and adolescence and are likely to continue over time. Risk factors for CVD include both modifiable factors and factors that cannot be changed.

MATERIALS AND METHODS

Using the MEDLINE^® electronic database, we reviewed the scientific literature for published studies evaluating the association between sleep-disordered breathing and cardiovascular damage in children.

RESULTS

In this review, we show the role of blood markers in demonstrating the inflammation caused by intermitted oxygen desaturations during sleep in both healthy and obese children. Several instrumental techniques, in addition to serum biomarkers, can be used to assess vascular endothelial damage and its deterioration in the form of a pre-atherosclerotic condition. The confirmation of their role as markers of inflammation and vascular damage is supported by normalisation after resolution or improvement of the sleep-disordered breathing with surgery.

DISCUSSION

Great attention should be given to this condition in infants and children as it will significantly affect their present and future well-being as they grow into adulthood. Healthcare professionals, especially paediatricians, should be trained to recognise the signs and symptoms of the disease in order to send children forward for specialist care in centres dealing with sleep-disordered breathing.

[Sleep-related breathing disorders in children and teenagers: diagnosis, consequences and comorbidities]

Obstructive sleep apnoea syndrome (OSAS) is a frequent sleep-related breathing disorder in children with a prevalence of approximately 3% between the ages of 3 and 8. Its origin is multifactorial (hypertrophy of pharyngeal soft tissues, narrowing of the bone airways, damage to the neuromuscular tone). The symptoms and clinical signs to look for during the day and at night are directly related to upper airway (UA) obstruction or poor sleep quality. After a complete anamnestic and clinical evaluation, including nasofibroscopy, the ENT specialist will refer to an adeno-amygdalectomy or night recording by polysomnography or polygraph to confirm the diagnosis in the child. Among adolescents, the prevalence of OSAS is reported to be between 0.5 and 6%. The main risk factors are obesity, male sex and a history of tonsillectomy. In addition to the classic symptoms of childhood OSAS, this syndrome may, in adolescents, manifest itself as a misleading semiology of dyssomnia, excessive daytime sleepiness and/or mood disorders. Differential diagnoses with risk behaviours, phase delay or narcolepsy should be systematically discussed. It is essential to record breathing during sleep. Even if the obstructive apnea/hypopnea index is low, it must be considered. In both children and adolescents, multidisciplinary management (ENT, orthodontist, maxillofacial physiotherapist, pulmonologist) should be early in order to avoid neurocognitive, behavioural, cardiovascular and metabolic complications. Maxillofacial surgery can be discussed from the age of 15. It is important not to forget to pay attention to the rules of healthy living and sleep as well as the management of obesity.

Heart rate variability in adults with obstructive sleep apnea: a systematic review

Obstructive Sleep Apnea is a common respiratory disorder characterized by recurrent nocturnal episodes of normal breathing interruption due to upper airway total or partial collapse. Obstructive sleep apnea and cardiovascular diseases has similar risk factors, but the first is also a predisposing factor for cardiovascular pathologies independently of individuals demographic characteristics or risk markers. Heart rate variability is a non-invasive method to evaluate the regulation of autonomic nervous system and its a promising marker for health and disease, such as cardiovascular and respiratory diseases. The aim was to review whether heart rate variability is altered in patients with obstructive sleep apnea. We searched in five databases, including BIREME, Cochrane, Scholar Google, MEDLINE/PubMed and Periodics CAPES, and reference lists were also searched. Only cross-sectional studies comparing the heart rate variability of obstructive sleep patients with controls were included. Two authors independently extracted data and assessed trial quality. Twelve studies (513 participants with obstructive sleep apnea and 340 controls) met the inclusion criteria. This review evidence that adults with obstructive sleep apnea may demonstrate diminished vagal tone and higher sympathetic responsiveness.

Polysomnographic correlates of endothelial function in children with obstructive sleep apnea

OBJECTIVES

To evaluate endothelial function in a large cohort of children clinically referred for suspected obstructive sleep apnea syndrome (OSAS), and to identify risk factors contributing to the presence of endothelial dysfunction (ED).

METHODS

Habitually snoring children (age range, 3-11 years) were recruited. All participants underwent overnight polysomnography (PSG). Endothelial function test used peripheral arterial tonometry (PAT) to derive the reactive hyperemia index (RHI). Subjects were then divided into mild OSA, moderate-severe OSA and primary snorers (PS), according to their obstructive apnea-hypopnea index (OAHI).

RESULTS

A total of 355 subjects were recruited. There were no differences in age, gender, or BMI z score among the three groups. Both mild and moderate-severe OSA groups had lower RHI than PS (P < 0.001, P = 0.001, respectively). Linear regression analysis revealed that RHI was positively correlated with age (r = 0.17, P = 0.002), BMI z score (r = 0.14, P = 0.008) and oxygen saturation nadir (r = 0.15, P = 0.006), but negatively correlated with oxygen desaturation index (ODI_3%; r = -0.19, P = 0.001) and respiratory-related arousal index (ArI-resp) (r = -0.24, P < 0.001). In stepwise regression analysis, age, BMI z score, and ArI-resp were independently associated with endothelial function (r = 0.34, P < 0.001).

CONCLUSION

Children with OSA are at increased risk for abnormal endothelial function than habitually snoring children. Furthermore, in addition to age and BMI, which are well-established factors affecting endothelial function, both intermittent hypoxia and sleep fragmentation during sleep also emerge as candidate risk factors contributing to endothelial dysfunction in snoring children.

CLINICAL TRIAL

Follow up of PS and OSAHS in Chinese children, https://clinicaltrials.gov/, Clinical number: NCT02447614.

Can myofunctional therapy increase tongue tone and reduce symptoms in children with sleep-disordered breathing?

PURPOSE

Data in the literature suggest that myofunctional therapy (MT) may be able to play a role in the treatment of children with sleep-disordered breathing (SDB). Our study investigated the effectiveness of MT in reducing respiratory symptoms in children with SDB by modifying tongue tone.

METHODS

Polysomnographic recordings were performed at baseline to assess obstructive sleep apnea (OSA) severity in 54 children (mean age 7.1 ± 2.5 years, 29 male) with SDB. Patients were randomly assigned to either the MT or no-MT group. Myofunctional evaluation tests, an assessment of tongue strength, tongue peak pressure, and endurance using the Iowa Oral Performance Instrument (IOPI), and nocturnal pulse oximetry were performed before (T0) and after (T1) 2 months of treatment.

RESULTS

MT reduced oral breathing (83.3 vs 16.6%, p < 0.0002) and lip hypotonia (78 vs 33.3%, p < 0.003), restored normal tongue resting position (5.6 vs 33.4%, p < 0.04), and significantly increased mean tongue strength (31.9 ± 10.8 vs 38.8 ± 8.3, p = 0.000), tongue peak pressure (34.2 ± 10.2 vs 38.1 ± 7.0, p = 0.000), and endurance (28.1 ± 8.9 vs 33.1 ± 8.7, p = 0.01) in children with SDB. Moreover, mean oxygen saturation increased (96.4 ± 0.6 vs 97.4 ± 0.7, p = 0.000) and the oxygen desaturation index decreased (5.9 ± 2.3 vs 3.6 ± 1.8, p = 0.001) after MT.

CONCLUSIONS

Oropharyngeal exercises appear to effectively modify tongue tone, reduce SDB symptoms and oral breathing, and increase oxygen saturation, and may thus play a role in the treatment of SDB.

Endothelial Dysfunction in Children With Obstructive Sleep Apnea Is Associated With Elevated Lipoprotein-Associated Phospholipase A2 Plasma Activity Levels

BACKGROUND

Obstructive sleep apnea (OSA) is a highly prevalent condition, especially in obese children, and has been associated with increased risk for endothelial dysfunction and dislipidemia, which are precursors of atherosclerosis. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is recognized as an independent risk factor for cardiovascular risk and atheromatous plaque activity. We hypothesized that Lp-PLA2 levels would be elevated in children with OSA, particularly among obese children who also manifest evidence of endothelial dysfunction.

METHODS AND RESULTS

One hundred sixty children (mean age 7.1±2.3 years), either nonobese with (n=40) and without OSA (n=40) or obese with (n=40) and without OSA (n=40) underwent overnight polysomnographic and postocclusive reperfusion evaluation and a fasting blood draw the morning after the sleep study. In addition to lipid profile, Lp-PLA2 plasma activity was assessed using a commercial kit. Obese children and OSA children had significantly elevated plasma Lp-PLA2 activity levels compared to controls. Furthermore, when both obesity and OSA were concurrently present or when endothelial function was present, Lp-PLA2 activity was higher. Treatment of OSA by adenotonsillectomy resulted in reductions of Lp-PLA2 activity (n=37; P<0.001).

CONCLUSIONS

Lp-PLA2 plasma activity is increased in pediatric OSA and obesity, particularly when endothelial dysfunction is present, and exhibits decreases on OSA treatment. The short-term and long-term significance of these findings in relation to cardiovascular risk remain undefined.

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.

Is obstructive sleep apnea syndrome in children season dependent?

INTRODUCTION

The most common cause of obstructive sleep apnea (OSA) in children is an enlargement of tonsils and/or adenoids. Previous studies have shown that the size of adenoids and tonsils is influenced by upper respiratory tract infections and exposure to allergens. The rate of exposure to bacteria, viruses, and allergens fluctuates from season to season. Therefore, we hypothesized that the rate of polysomnograms positive for OSA may vary according to season.

OBJECTIVE

The objective of this study is to determine whether the prevalence of OSA in children, as determined by polysomnography, is affected by the season during which the study was performed.

METHODS

We retrospectively reviewed polysomnography tests of 296 children, ages 0-12 years, referred for suspected OSA. We compared the Obstructive Apnea Hypopnea Index (OAHI) between the seasons and the rates of abnormal tests in each season according to the degree of severity.

RESULTS

The mean OAHI did not significantly differ among the seasons (winter, 3.0 ± 5.0; spring, 3.0 ± 4.9; summer, 4.0 ± 6.3; fall, 3.4 ± 5.7, p = 0.183). When dividing the OAHI by levels of severity, no seasonality was found in moderate (winter, 13.8 %; spring, 6.7 %; summer, 11.7 %; fall, 14.1 %, p = NS) and severe OSA (winter, 8.8 %; spring, 11.2 %; summer, 10 %; fall, 7.8 %, p = NS). There was a small increase in the frequency of mild OSA diagnoses in the summer compared to the other seasons.

CONCLUSION

In this study, season does not appear to affect the rate of diagnosis of significant OSA in children. Re-evaluation during a different season is unlikely to provide different results and may postpone surgery unnecessarily.

Mean Platelet Volume, Vitamin D and C Reactive Protein Levels in Normal Weight Children with Primary Snoring and Obstructive Sleep Apnea Syndrome

INTRODUCTION

Studies on Mean Platelet Volume (MPV) in children with Sleep Disordered Breathing (SDB) report conflicting results and the hypothesis of an intermittent hypoxemia leading to a systemic inflammation is reaching consensus. Vitamin D exerts anti-inflammatory properties and its deficiency has been supposed to play a role in sleep disorders. Emerging interest is rising about Primary Snoring (PS) since it is reasonable that also undetectable alteration of hypoxia might predispose to an increased production of inflammatory mediators. In this perspective, in a group of children affected by SDB, our aim was to investigate MPV, vitamin D and C Reactive Protein (CRP) levels, which had been previously evaluated separately in different studies focused only on Obstructive Sleep Apnea Syndrome (OSAS).

MATERIALS AND METHODS

We enrolled 137 children: 70 healthy controls (HC), 67 affected by SDB undergoing a polysomnographic evaluation, 22 with a diagnosis of PS and 45 with a diagnosis of OSAS. All patients underwent routine biochemical evaluations including blood cell counts, CRP and vitamin D.

RESULTS

Children affected by SDB had a mean age of 8.49±2.19 and were prevalently males (23 females, 34%; 44 males, 66%). MPV levels were higher in OSAS and PS when compared to HC; platelet count (PLT) and CRP levels were higher while Vitamin D levels were lower in children with SDB when compared to HC. MPV levels were correlated with PLT (r = -0.54; p<0.001), vitamin D (r = -0.39; p<0.001) and CRP (r = 0.21; p<0.01). A multiple regression was run to predict MPV levels from vitamin D, CRP and PLT and these variables significantly predicted MPV (F = 17.42, p<0.0001; adjusted R2 = 0.37). Only platelet count and vitamin D added statistically significantly to the prediction (p<0.05).

CONCLUSION

The present study provides evidence of higher MPV and lower vitamin D levels in children with PS as well as in children with OSAS, and supports the underlying inflammation, hence, highlighting the importance of an early diagnosis of this previously considered benign form of SDB.

Body Fat Composition: A Predictive Factor for Sleep Related Breathing Disorder in Obese Children

INTRODUCTION

The association between body fat composition as measured by dual energy x-ray absorptiometry (DEXA) scanning and pediatric sleep related breathing disorder (SRBD) is not well established. We investigated the relationship between body mass index (BMI) and DEXA parameters and their association with SRBD in obese children.

PATIENTS AND METHODS

Overnight polysomnography was performed on obese/overweight children (10-17 years) with habitual snoring. Total body fat mass (g), trunk fat mass (g), total body % fat, and trunk % fat were determined by DEXA.

RESULTS

Forty-one subjects were studied. Logarithm (Log) total arousal index correlated with BMI (p < 0.01, r = 0.473), total body fat mass (p < 0.05, r = 0.331), and trunk fat mass (p < 0.05, r = 0.319). Log desaturation index correlated with BMI (p < 0.05, r = 0.313), total body fat mass (p < 0.05, r = 0.375), and trunk fat mass (p < 0.05, r = 0.391), whereas obstructive apnea hypopnea index (OAHI) did not. In males 10-12 years, there was a significant correlation between Log total arousal index and obesity parameters, but not for males aged 13-17 years. BMI correlated with DEXA parameters in all subjects: total body fat mass (p < 0.001, r = 0.850); total body % fat (p < 0.01, r = 0.425); trunk fat mass (p < 0.001, r = 0.792) and trunk % fat (p < 0.05, r = 0.318) and in 10-12 year old males. This relationship was not significant in males aged 13-17 years.

CONCLUSIONS

Total body fat mass and trunk fat mass as well as BMI correlated with total arousal index and desaturation index. BMI correlated with DEXA parameters in 10-12 year old males but not in 13-17 year old males. The value of using DEXA scanning to study the relationship between obesity and SRBD may depend on age and pubertal stage.

Pupillometric findings in children with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) leads to intermittent hypoxia, activation of the sympathetic nervous system, and eventually cardiovascular morbidity. Alterations in autonomic nervous system (ANS) tone and reflexes are likely to play major roles in OSA-associated morbidities, and have been identified in a subset of children with OSA.

OBJECTIVES

To evaluate whether pupillometry, a noninvasive and rapid bedside test for the assessment of autonomic nervous system dysfunction (ANS), would detect abnormal ANS function in children with OSA.

METHODS

Children ages 2-12 years underwent polysomnography (PSG), and were divided based on PSG findings into two groups; Habitual Snorers (HS; AHI < 1 h/TST, n = 17) and OSA (AHI > 1 h/TST, n = 49), the latter then sub-divided into AHI severity categories (>1 but <5, >5 but <10, and >10 h/TST). Pupillometric measurements were performed during the clinic visit in a dark room using an automated pupillometer device.

RESULTS

A total of 66 subjects with a mean age of 7.3 ± 2.6 years were recruited. There were no statistically significant differences between any of the groups, even when comparing severe OSA (n = 15) and HS in any of the measures related to pupillary reflexes. However, mild, yet significant increases in systolic blood pressure and morning plasma norepinephrine levels were detected in the severe OSA group.

CONCLUSION

Although ANS perturbations are clearly present in a proportion of children with OSA, particularly those with severe disease, pupillary responses do not appear to provide a sensitive method for the detection of ANS dysfunction in OSA children.

Obesity and Altered Sleep: A Pathway to Metabolic Derangements in Children?

Obstructive sleep apnea (OSA) is a frequent disorder in children and is primarily associated with adenotonsillar hypertrophy. The prominent increases in childhood overweight and obesity rates in the world even among youngest of children have translated into parallel increases in the prevalence of OSA, and such trends are undoubtedly associated with deleterious global health outcomes and life expectancy. Even an obesity phenotype in childhood OSA, more close to the adult type, has been recently proposed. Reciprocal interactions between sleep in general, OSA, obesity, and disruptions of metabolic homeostasis have emerged in recent years. These associations have suggested the a priori involvement of complex sets of metabolic and inflammatory pathways, all of which may underlie an increased risk for increased orexigenic behaviors and dysfunctional satiety, hyperlipidemia, and insulin resistance that ultimately favor the emergence of metabolic syndrome. Here, we review some of the critical evidence supporting the proposed associations between sleep disruption and the metabolism-obesity complex. In addition, we describe the more recent evidence linking the potential interactive roles of OSA and obesity on metabolic phenotype.

Endothelial dysfunction and oxidative stress in children with sleep disordered breathing: role of NADPH oxidase

OBJECTIVE

Oxidative stress plays a crucial role in impairing endothelial function in sleep disordered breathing (SDB) but the underlying mechanism is still undefined. The objective of this study was to evaluate the interplay between oxidative stress, assessed by serum isoprostanes (8-iso-PGF2α) and soluble NOX2-dp (sNOX2-dp), and endothelial function, assessed by flow-mediated dilation (FMD), in children with SDB and healthy controls (HC).

METHODS

One-hundred forty-four children including 45 with primary snoring (PS), 22 with obstructive sleep apnea (OSA) and 67 HC were recruited in this study; in 15 out of 22 OSA children FMD, serum 8-iso-PGF2α and sNOX2-dp were assessed before and after one month post adeno-tonsillectomy (AT).

RESULTS

Compared with HC, OSA and PS children had significantly higher sNOX2-dp and serum 8-iso-PGF2α levels and lower FMD; compared with PS, FMD was significantly lower in OSA children. No significant difference for sNOX2-dp and serum 8-iso-PGF2α was observed between OSA and PS children. FMD was inversely correlated with sNOX2-dp levels (p<0.001) and with serum 8-iso-PGF2α (p<0.001). In multiple linear regression analysis, sNOX2-dp (p<0.001) and serum 8-iso-PGF2α (p<0.001) were the only independent predictive variables associated with FMD. AT significantly decreased sNOX2-dp and serum 8-iso-PGF2α levels (from 38.2±8.8 to 22.4±11.1 pg/ml, p<0.001, and from 281.4±69.7 to 226.0±66.4 pg/ml, p<0.001, respectively); conversely, FMD significantly increased after AT in OSA children (from 3.0±1.5 to 8.0±2.8%, p<0.001).

CONCLUSION

This study suggests that NOX2-derived oxidative stress is involved in artery dysfunction in SDB children. Such hypothesis is reinforced by FMD improvement after AT coincidentally with oxidative stress lowering.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02247167.

Outcomes after adenotonsillectomy using a fixed anesthesia protocol in children with obstructive sleep apnea

OBJECTIVE

To document the effects of a fixed anesthesia protocol on peri-operative events in children undergoing adenotonsillectomy for obstructive sleep apnea (OSA).

METHODS

A non-randomized prospective study was conducted during the years 2011-2013 within a setting of a tertiary-level university hospital. Sixty five children with polysomnographically proven OSA undergoing adenotonsillectomy were enrolled in the study and stratified into three groups based on severity. The relationship between severity of OSA as determined by apnea-hypopnea index (AHI) and oxygen saturation (SpO2) nadir were compared with time taken to (i) extubation following emergence and (ii) discharge from the post-anesthesia care unit. Adjustments were made in the dosages of premedication (midazolam) and opioid analgesic administered following induction (hydromorphone) depending on the severity of OSA. A non-validated but fixed anesthesia protocol tailored to the severity of OSA was used in all patients. In addition, all adverse events were also monitored.

RESULTS

A paradoxical, yet significant reduction in emergence time was observed among patients with severe OSA following surgery (ANOVA, Tukey-Kramer post hoc tests, P<0.001). There were also fewer adverse events in this group.

CONCLUSIONS

Emergence from anesthesia after adenotonsillectomy may be positively influenced by an anesthetic technique titrated according to the severity of OSA. Adverse respiratory events due to the severity of sleep apnea and attendant hypoxemia may be minimized and outcomes improved with similarly tailored protocols.

Correlation of salivary alpha amylase level and adenotonsillar hypertrophy with sleep disordered breathing in pediatric subjects

STUDY OBJECTIVES

Obstructive sleep apnea syndrome (OSAS) and sleep disordered breathing (SDB) can affect the sympathetic adrenomedullary system (SAM). As a biomarker of SAM activity, salivary α-amylase (sAA) in pediatric subjects was evaluated whether it has any correlation with polysomnographic (PSG) parameters related to SDB.

METHODS

Sixty-seven children who attended our clinic during 1 year were enrolled prospectively and underwent clinical examinations and in-lab polysomnography. The sAA was measured at 2 points--at night before PSG and in the early morning after PSG.

RESULTS

Subjects were divided into control (n = 26, apneahypopnea index [AHI] < 1) and OSAS (n = 41, AHI ≥ 1) groups. The OSAS group was subdivided according to AHI (mild-moderate, 1 ≤ AHI < 10; severe, AHI ≥ 10). The sAA subtraction and ratio (p = 0.014 and p < 0.001, respectively) were significantly higher in severe OSAS than in the mild-moderate and control groups. Although oxygen desaturation index (ODI) and AHI were significantly associated with sAA, sAA in the OSAS group was not related to lowest oxygen saturation or adenotonsillar hypertrophy.

CONCLUSION

sAA was well related to polysomnographic (PSG) parameters related to SDB, such as AHI and ODI. Therefore, screening test for sAA in children suspected to have SBD may help to identify OSAS patients from control.

Salivary biomarkers of obstructive sleep apnea syndrome in children

OBJECTIVES

The present pilot study was performed to evaluate the HPA axis and ANS activity by measuring salivary cortisol and α-amylase diurnal trajectory and production, respectively, in mild or moderate-to-severe (MS) OSA-affected, but otherwise healthy, children. Moreover, a correlative analysis was performed between the salivary biomarker concentrations and the PSG variables characterizing the OSA severity.

METHODS

We studied 27 consecutive OSA patients (13 mild OSA; 14 MS OSA) and seven healthy children who were enrolled as controls by collecting salivary samples and measuring cortisol and α-amylase levels using enzyme-linked bioassays.

RESULTS

Compared with controls, both mild and MS OSA children showed: (1) increased salivary cortisol diurnal production, (2) maintenance of the physiological circadian activity of the HPA axis, and (3) no changes in α-amylase diurnal trajectory and production. In addition, morning salivary cortisol concentrations was negatively associated with the disease severity in the MS OSA group.

CONCLUSIONS

OSA is associated with dysregulation of the HPA axis activity in children, the latter potentially underlying some of the adverse consequences of the disease.

Oropharyngeal exercises to reduce symptoms of OSA after AT

PURPOSE

This study evaluated the efficacy of oropharyngeal exercises in children with symptoms of obstructive sleep apnea syndrome (OSA) after adenotonsillectomy.

METHODS

Polysomnographic recordings were performed before adenotonsillectomy and 6 months after surgery. Patients with residual OSA (apnea-Hypopnea Index, AHI > 1 and persistence of respiratory symptoms) after adenotonsillectomy were randomized either to a group treated with oropharyngeal exercises (group 1) or to a control group (group 2). A morphofunctional evaluation with Glatzel and Rosenthal tests was performed before and after 2 months of exercises. All the subjects were re-evaluated after exercise through polysomnography and clinical evaluation. The improvement in OSA was defined by ΔAHI: (AHI at T1 - AHI at T2)/AHI at T1 × 100.

RESULTS

Group 1 was composed of 14 subjects (mean age, 6.01 ± 1.55) while group 2 was composed of 13 subjects (mean age, 5.76 ± 0.82). The AHI was 16.79 ± 9.34 before adenotonsillectomy and 4.72 ± 3.04 after surgery (p < 0.001). The ΔAHI was significantly higher in group 1 (58.01 %; range from 40.51 to 75.51 %) than in group 2 (6.96 %; range from -23.04 to 36.96 %). Morphofunctional evaluation demonstrated a reduction in oral breathing (p = 0.002), positive Glatzel test (p < 0.05), positive Rosenthal test (p < 0.05), and increased labial seal (p < 0.001), and lip tone (p < 0.05).

CONCLUSIONS

Oropharyngeal exercises may be considered as complementary therapy to adenotonsillectomy to effectively treat pediatric OSA.

Impact of sleep respiratory disorders on endothelial function in children

Obstructive sleep apnea syndrome (OSAS) in children can induce endothelial dysfunction, a well-known early marker of atherosclerosis. The study aimed to evaluate a link among endothelial function (measured by flow-mediated vasodilation (FMD)), obesity (evaluated by body mass index (BMI)), and sleep disordered breathing (SDB), assessed with apnoea/hypopnoea index (AHI), in a paediatric population. We demonstrated that our little OSAS patients showed an impaired endothelial function as compared to controls. In particular, the higher the AHI, the worst the FMD values and thus the endothelial function. Although the population sample is small, this study demonstrated that OSAS could impair endothelial function and worsen cardiovascular risk profile since childhood.

Circulating adropin concentrations in pediatric obstructive sleep apnea: potential relevance to endothelial function

OBJECTIVE

To test the hypothesis that concentrations of adropin, a recently discovered peptide that displays important metabolic and cardiovascular functions, are lower in obstructive sleep apnea (OSA), especially when associated with endothelial dysfunction.

STUDY DESIGN

Age-, sex-, and ethnicity-matched children (mean age, 7.2 ± 1.4 years) were included into 1 of 3 groups based on the presence of OSA in an overnight sleep study, and on the time to postocclusive maximal reperfusion (Tmax >45 seconds) with a modified hyperemic test. Plasma adropin concentrations were assayed using a commercial enzyme-linked immunosorbent assay kit.

RESULTS

Among controls, the mean morning adropin concentration was 7.4 ng/mL (95% CI, 5.2-16.3 ng/mL). Children with OSA and abnormal endothelial function (EF) (OSA(+)/EF(+) group) had significantly lower adropin concentrations (2.7 ± 1.1 ng/mL; n = 35) compared with matched controls (7.6 ± 1.4 ng/mL; n = 35; P < .001) and children with OSA and normal EF (OSA(+)/EF(-) group; 5.8 ± 1.5 ng/mL; n = 47; P < .001). A plasma adropin concentration <4.2 ng/mL reliably predicted EF status, but individual adropin concentrations were not significantly correlated with age, body mass index z-score, obstructive apnea-hypopnea index, or nadir oxygen saturation. Mean adropin concentration measured after adenotonsillectomy in a subset of children with OSA (n = 22) showed an increase in the OSA(+)/EF(+) group (from 2.5 ± 1.4 to 6.4 ± 1.9 ng/mL; n = 14; P < .01), but essentially no change in the OSA(+)EF(-) group (from 5.7 ± 1.3 to 6.4 ± 1.1 ng/mL; n = 8; P > .05).

CONCLUSION

Plasma adropin concentrations are reduced in pediatric OSA when endothelial dysfunction is present, and return to within normal values after adenotonsillectomy. Assessment of circulating adropin concentrations may provide a reliable indicator of vascular injury in the context of OSA in children.

T regulatory lymphocytes and endothelial function in pediatric obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a low-grade inflammatory disease affecting the cardiovascular and metabolic systems. Increasing OSA severity reduces T-regulatory lymphocytes (Tregs) in OSA children. Since Tregs modulate endothelial activation, and attenuate insulin resistance, we hypothesized that Tregs are associated with endothelial and metabolic dysfunction in pediatric OSA.

METHODS

50 consecutively recruited children (ages 4.8-12 years) underwent overnight polysomnography and fasting homeostatic model (HOMA) of insulin resistance was assessed. Percentage of Tregs using flow cytometry, and endothelial function, expressed as the time to peak occlusive hyperemia (Tmax), were examined. In a subgroup of children (n = 21), in vitro Treg suppression tests were performed.

RESULTS

Circulating Tregs were not significantly associated with either BMI z score or HOMA. However, a significant inverse correlation between percentage of Tregs and Tmax emerged (p<0.0001, r = -0.56). A significant negative correlation between Tregs suppression and the sleep pressure score (SPS), a surrogate measure of sleep fragmentation emerged (p = 0.02, r = -0.51) emerged, but was not present with AHI.

CONCLUSIONS

Endothelial function, but not insulin resistance, in OSA children is strongly associated with circulating Tregs and their suppressive function, and appears to correlate with sleep fragmentation. Thus, alterations in T cell lymphocytes may contribute to cardiovascular morbidity in pediatric OSA.

Alterations in circulating T-cell lymphocyte populations in children with obstructive sleep apnea

STUDY OBJECTIVES

Changes in lymphocyte phenotype and functionality have been described in adult patients with obstructive sleep apnea (OSA). We hypothesized that OSA is associated with T lymphocyte alterations in children, particularly in T regulatory lymphocytes (T regs), and aimed to characterize circulating T lymphocyte subsets in children with OSA.

DESIGN

Cross-sectional.

SETTING

Kosair Children's Hospital (Louisville, KY, USA) and Comer Children's Hospital (Chicago, IL, USA).

PARTICIPANTS

Consecutively recruited children being evaluated for habitual snoring.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Overnight polysomnography (PSG) was performed and a fasting blood sample was obtained from the patients. Flow cytometry was performed on peripheral blood mononuclear cells stained for CD3, CD4, CD8, CD25, FOXP3, interleukin-4 (IL-4), interferon-γ (IFN-γ), and IL-17. Patients were divided into three groups based on their PSG: controls (apnea-hypopnea indices [AHI] < 1/h total sleep time [TST]), mild OSA (1 ≤ AHI < 5/hTST), moderate-severe OSA (AHI ≥ 5/h TST). The percentage of CD4+ and T reg lymphocytes differed across groups. Children with moderate-severe OSA had significantly reduced T reg than control children (median [interquartile range] 4.8 [3.8-5.7% CD4+] versus 7.8 [7.0-9.2% CD4+]; P < 0.001). There were also significant differences in the percentage of T helper 1 (Th1) lymphocytes and in Th1:Th2 ratios between groups. Children with moderate-severe OSA had increased Th1 cells (P = 0.001) and Th1:Th2 ratios (P = 0.0026) compared with children with mild OSA and control children. Associations between AHI and T reg (P = 0.0003; r = -0.46), CD4+ lymphocytes (P = 0.0047; r = -0.37), and Th1:Th2 ratios (P = 0.0009; r = 0.43) emerged. In addition, the percentage of T reg was inversely correlated with Th1:Th2 ratios (P = 0.029; r = -0.29).

CONCLUSIONS

Pediatric OSA is associated with reduced T reg population and altered Th1:Th2 balance toward Th1 predominance, suggesting a shift to a proinflammatory state. The changes in lymphocytic phenotypes associated with OSA may contribute to the variance in systemic inflammation and downstream morbidities associated with this condition.

Macrophage migration inhibitory factor gene polymorphisms and plasma levels in children with obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is associated with increased risk for cardiovascular and metabolic dysfunction in both adults and children. In adults with OSA, serum levels of macrophage migration inhibitory factor (MIF) are elevated. Therefore, we assessed plasma MIF levels and MIF allelic variant frequencies in children with and without OSA (NOSA).

METHODS

A total of 614 consecutive children ages 5-8 years were recruited. Children were divided into those with OSA and NOSA based on the apnea-hypopnea index (AHI). In addition to lipid profile, hsCRP, and fasting insulin and glucose levels, plasma MIF levels were assayed using ELISA, and 28 single nucleotide polymorphisms (SNPs) covering the region were genotyped. Linkage disequilibrium and haplotype blocks were analyzed using Haploview version 4.2 software.

RESULTS

Morning plasma MIF levels were increased in children with OSA. Of the 28 SNPs tested, the frequency of rs10433310 minor allele was significantly decreased in OSA. This SNP was also associated with reduced fasting insulin and hsCRP levels in OSA. The minor allele frequency of all other 27 SNPs was similar in OSA and NOSA groups.

CONCLUSIONS

Childhood OSA is associated with higher plasma MIF, hsCRP, and fasting insulin levels that promote cardiometabolic risk, and the MIF gene SNP rs10433310 may account for some of the variance in such risk.

Childhood obesity and sleep: relatives, partners, or both?--a critical perspective on the evidence

In modern life, children are unlikely to obtain sufficient or regular sleep and waking schedules. Inadequate sleep affects the regulation of homeostatic and hormonal systems underlying somatic growth, maturation, and bioenergetics. Therefore, assessments of the obesogenic lifestyle, including as dietary and physical activity, need to be coupled with accurate evaluation of sleep quality and quantity, and coexistence of sleep apnea. Inclusion of sleep as an integral component of research studies on childhood obesity should be done as part of the study planning process. Although parents and health professionals have quantified normal patterns of activities in children, sleep has been almost completely overlooked. As sleep duration in children appears to have declined, reciprocal obesity rates have increased. Also, increases in pediatric obesity rates have markedly increased the risk of obstructive sleep apnea syndrome (OSAS) in children. Obesity and OSAS share common pathways underlying end-organ morbidity, potentially leading to reciprocal amplificatory effects. The relative paucity of data on the topics covered in the perspective below should serve as a major incentive toward future research on these critically important concepts.

Obstructive sleep apnea in Treacher Collins syndrome

The aim of the present study was to investigate the prevalence of obstructive sleep apnea syndrome (OSAS) among the Norwegian population with Treacher Collins syndrome (TCS). A secondary aim was to establish whether TCS phenotype severity is associated with OSAS severity. A prospective case study design was used. Individuals who were 5 years old and above with a known diagnosis of TCS in Norway were invited to participate in a study. The study included genetic testing, medical and dental examinations and polysomnography. All participants demonstrated disturbed respiration during sleep; 18/19 met the diagnostic criteria for OSAS. Subjectively evaluated snoring was not a reliable predictor of OSAS. We found no significant association between TCS phenotype severity and the severity of OSAS. OSAS is common in TCS, but there is no association with the phenotype severity. Individuals diagnosed with TCS must undergo sleep studies to identify the presence of OSAS.

Endothelial dysfunction in children without hypertension: potential contributions of obesity and obstructive sleep apnea

BACKGROUND

Endothelial dysfunction can develop in the context of both obesity and obstructive sleep apnea (OSA) in children. However, the potential interactions between OSA and obesity have not been defined.

METHODS

Children who were prepubertal and nonhypertensive were recruited. Endothelial function was assessed in a morning fasted state, using a modified hyperemic test involving cuff-induced occlusion of the radial and ulnar arteries, and blood was drawn for assessment of myeloid-related protein 8/14 (MRP8/14) levels using a commercial enzyme-linked immunosorbent assay. Overnight polysomnography defined the presence of OSA or absence of OSA (NOSA) in subjects investigated for sleep-disordered breathing. Anthropometric measurements were performed to assign subjects to obese (OB) and nonobese (NOB) categories.

RESULTS

Fifty-four children with OSA who were obese and nonobese (mean age, 7.90 ± 0.26 years; mean BMI z-score, 1.70 ± 0.3; obstructive apnea-hypopnea index [OAHI], 7.36 ± 1.09) were compared with 54 children without OSA who were obese and nonobese (mean age, 8.26 ± 0.24 years; mean BMI z-score, 1.41 ± 0.18; OAHI, 0.86 ± 0.07). Of those subjects, 62.5% of the OB-OSA category, 38.7% of the OB-NOSA category, and 20.0% of the NOB-OSA category had evidence of endothelial dysfunction, compared with 0.0% of the NOB-NOSA category (P < .01). The degree of endothelial dysfunction in all groups was associated with circulating MRP8/14 levels (r = 0.343, P < .001).

CONCLUSIONS

Both obesity and OSA can independently increase the risk for endothelial dysfunction, and the concurrent presence of both markedly increases such risk. Although the mechanisms underlying endothelial dysfunction remain unclear, a potential role for MRP8/14 as an inflammatory biomarker of endothelial dysfunction is suggested.

Seasonal variability of sleep-disordered breathing in children

INTRODUCTION

Snoring and sleep-disordered breathing (SDB) are frequent pediatric conditions. Although allergies and respiratory viruses have been pathophysiologically implicated in these conditions, their seasonal distribution has not been examined.

METHODS

The records of all children participating in a prospective, cross-sectional community-based research study that included a questionnaire on snoring frequency and loudness and an overnight sleep study were retrospectively assessed for seasonal patterns based on the day the children were evaluated.

RESULTS

A total of 1,051 children were included with a mean age of 7 years. There were no seasonal differences in the number of children evaluated or in their demographic characteristics. However, the odds of increased snoring frequency and loudness were significantly higher in spring and summer and lowest in fall (P < 0.001). However, the mean AHI was highest and the nadir SaO(2) was lowest in winter and spring compared to summer and fall (P < 0.001 and P < 0.03, respectively).

CONCLUSION

Snoring and the severity of SDB exhibit distinct and essentially non-overlapping patterns of seasonal variation, with peaks in spring-summer for snoring and peaks in winter-spring for SDB severity. These findings suggest that both seasonal viral and allergen burdens may contribute to SDB severity and may prompt differing clinical referral patterns throughout the year.

Inflammatory pathways in children with insufficient or disordered sleep

Sleep is not only an essential physiological function, but also serves important roles in promoting growth, maturation, and overall health of children and adolescents. There is increasing interest regarding the impact of sleep and its disorders on the regulation of inflammatory processes and end-organ morbidities, particularly in the context of metabolic and cardiovascular diseases (CVD) and their complications. Obstructive sleep apnea syndrome (OSAS) is an increasingly common health problem in children, and in the last decade, the emergence of increasing obesity rates has further led to remarkable increases in the prevalence of OSAS, along with more prominent neurocognitive, behavioral, cardiovascular and metabolic morbidities. Although the underlying mechanisms leading to OSAS-induced morbidities are likely multi-factorial, and remain to be fully elucidated, activation of inflammatory pathways by OSAS has emerged as an important pathophysiological component of the end-organ injury associated with this disorder. To this effect, it would appear that OSAS could be viewed as a chronic, low-grade inflammatory disorder. Furthermore, the concurrent presence of obesity and OSAS poses a theoretically increased risk of OSAS-related complications. In this review, we will critically review the current state of research regarding the impact of insufficient and disrupted sleep and OSAS on the immune processes and inflammatory pathways that underlie childhood OSAS as a distinctive systemic inflammatory condition in children, and will explore potential interactions between OSAS and obesity.

Neurocognitive and endothelial dysfunction in children with obstructive sleep apnea

OBJECTIVE

Pediatric obstructive sleep apnea syndrome (OSAS) is associated with neurocognitive and endothelial dysfunction. However, it is unclear whether these 2 frequent morbidities of OSAS in children represent similar or different underlying pathophysiological processes, because they have never been concurrently assessed in children.

METHODS

Consecutive children (ages 5-8 years) with polysomnographically based OSAS underwent cognitive battery evaluation (Differential Ability Scales and the NeuroPsychological Assessment Battery) and cuff-occlusion hyperemic tests for assessment of endothelial function. The presence of neurocognitive deficits (NC(+)) was defined on the basis of the presence of ≥ 2 abnormal cognitive test results. Endothelial dysfunction (ED(+)) was defined as a time to maximal postocclusive hyperemic response of ≥ 45 seconds (T(max)).

RESULTS

Twenty-one control children and 87 children with OSAS completed both cognitive and endothelial tests. Of these children, 48 were NC(+) and 50 had a T(max) of ≥ 45 seconds, and at least 80% of these children were in both groups. Conversely, among children in whom there was no presence of neurocognitive deficits (NC(-)), only 25.6% were ED(+), whereas among those without endothelial dysfunction (ED(-)) only 21.6% were NC(+). Furthermore, approximately one-third of the children with OSAS was NC(-) and ED(-). Thus, findings on hyperemic vascular responses were highly predictive of neurocognitive status.

CONCLUSIONS

Endothelial dysfunction and neurocognitive deficits are more likely to coexist than otherwise predicted from the frequency of each of these morbidities alone in pediatric OSAS. Thus, both of these morbid consequences may share similar pathogenetic mechanisms. Furthermore, a simple test such as the postocclusive hyperemic vascular response may help detect at-risk patients for neuropsychological deficits.