Morbidity of obstructive sleep apnea in children: facts and theory

Neuropsychological functioning after adenotonsillectomy in children with obstructive sleep apnea: A meta-analysis

The present study aimed to investigate the efficacy of adenotonsillectomy (AT) for children with obstructive sleep apnea syndrome (OSAS) and the improvement of their cognitive function. Studies on cognitive performance of OSAS children treated with or without AT were identified by searching the Pubmed, EMBASE and Cochrane library. A meta-analysis was conducted to analyze the literature. The random-effects model was used to evaluate 11 eligible studies using an inverse- variance method. The neuropsychological test results of 4 cognitive domains (general intelligence, memory, attention-executive function and verbal ability) were obtained and analyzed. By comparison of cognitive function between OSAS children and healthy controls, the effect sizes of each domain were achieved as follows: general intelligence,-0.5 (P<0.0001); memory,-0.18 (P=0.02); attention-executive function,-0.21 (P=0.002); and verbal ability,-0.48 (P=0.0006). The effect sizes of general intelligence, memory, attention-executive function, and verbal ability after AT compared to baseline level were-0.37 (P=0.008),-0.36 (P=0.0005),-0.02 (P=0.88), and-0.45 (P=0.009), respectively. Comparing the cognitive ability between OSAS children after AT and healthy controls showed that the effect sizes were-0.54 (P=0.0009),-0.24 (P=0.12),-0.17 (P=0.35), and-0.45 (P=0.009) in general intelligence, memory, attention-executive function, and verbal ability, respectively. Our results confirmed that OSAS children performed worse than healthy children in terms of the 4 cognitive domains investigated. After 6-12 months of observation, significant improvement in attention-executive function and verbal ability were found in OSAS children treated with AT compared to their baseline level; restoration of attention-executive function and memory were observed in OSAS children after AT in comparison to healthy controls. Further rigorous randomized controlled trials should be conducted to obtain definitive conclusions.

Comparisons of thyroid hormone, intelligence, attention, and quality of life in children with obstructive sleep apnea hypopnea syndrome before and after endoscopic adenoidectomy

Objective. The aim of this study was to compare the differences in thyroid hormone, intelligence, attention, and quality of life (QoL) of children with obstructive sleep apnea hypopnea syndrome (OSAHS) before and after endoscopic adenoidectomy. Method. A total of 35 OSAHS children (21 males and 14 females with a mean age of 6.81 ± 1.08 years) were included in this study for analyzing the levels of thyroid hormone, intelligence, attention, and QoL. There were 22 children underwent endoscopic adenoidectomy with bilateral tonsillectomy (BT), while the other 13 children who underwent endoscopic adenoidectomy without bilateral tonsillectomy without BT. Results. Our results revealed no significant difference in serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid stimulating hormone (TSH) levels in OSAHS children before and after endoscopic adenoidectomy (all P > 0.05). However, there were significant differences in full-scale intelligence quotient (FIQ) (92.45 ± 5.88 versus 106.23 ± 7.39, P < 0.001), verbal intelligence quotient (VIQ) (94.17 ± 15.01 versus 103.91 ± 9.74, P = 0.006), and performance intelligence quotient (PIQ) (94.12 ± 11.04 versus 104.31 ± 10.05, P = 0.001), attention (98.48 ± 8.74 versus 106.87 ± 8.58, P < 0.001), and total OSA-18 scores (87.62 ± 17.15 versus 46.61 ± 10.15, P < 0.001) between before and after endoscopic adenoidectomy in OSAHS children. Conclusion. Our findings provided evidence that the intelligence, attention, and QoL of OSAHS children may be significantly improved after endoscopic adenoidectomy.

Polymorphisms in nitric oxide synthase and endothelin genes among children with obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is associated with adverse and interdependent cognitive and cardiovascular consequences. Increasing evidence suggests that nitric oxide synthase (NOS) and endothelin family (EDN) genes underlie mechanistic aspects of OSA-associated morbidities. We aimed to identify single nucleotide polymorphisms (SNPs) in the NOS family (3 isoforms), and EDN family (3 isoforms) to identify potential associations of these SNPs in children with OSA.

Methods

A pediatric community cohort (ages 5–10 years) enriched for snoring underwent overnight polysomnographic (NPSG) and a fasting morning blood draw. The diagnostic criteria for OSA were an obstructive apnea-hypopnea Index (AHI) >2/h total sleep time (TST), snoring during the night, and a nadir oxyhemoglobin saturation <92%. Control children were defined as non-snoring children with AHI <2/h TST (NOSA). Endothelial function was assessed using a modified post-occlusive hyperemic test. The time to peak reperfusion (Tmax) was considered as the indicator for normal endothelial function (NEF; Tmax<45 sec), or ED (Tmax≥45 sec). Genomic DNA from peripheral blood was extracted and allelic frequencies were assessed for, NOS1 (209 SNPs), NOS2 (122 SNPs), NOS3 (50 SNPs), EDN1 (43 SNPs), EDN2 (48 SNPs), EDN3 (14 SNPs), endothelin receptor A, EDNRA, (27 SNPs), and endothelin receptor B, EDNRB (23 SNPs) using a custom SNPs array. The relative frequencies of NOS-1,-2, and −3, and EDN-1,-2,-3,-EDNRA, and-EDNRB genotypes were evaluated in 608 subjects [128 with OSA, and 480 without OSA (NOSA)]. Furthermore, subjects with OSA were divided into 2 subgroups: OSA with normal endothelial function (OSA-NEF), and OSA with endothelial dysfunction (OSA-ED). Linkage disequilibrium was analyzed using Haploview version 4.2 software.

Results

For NOSA vs. OSA groups, 15 differentially distributed SNPs for NOS1 gene, and 1 SNP for NOS3 emerged, while 4 SNPs for EDN1 and 1 SNP for both EDN2 and EDN3 were identified. However, in the smaller sub-group for whom endothelial function was available, none of the significant SNPs was retained due to lack of statistical power.

Conclusions

Differences in the distribution of polymorphisms among NOS and EDN gene families suggest that these SNPs could play a contributory role in the pathophysiology and risk of OSA-induced cardiovascular morbidity. Thus, analysis of genotype-phenotype interactions in children with OSA may assist in the formulation of categorical risk estimates.

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.

School nurses can address existing gaps in school-age sleep research

Sleep has been linked to a host of physical, behavioral, and emotional outcomes, and research has documented that youth across the globe are experiencing inadequate sleep. Despite this knowledge, however, very little research has been conducted on school-age children; much of the extant research has focused on infants, toddlers, preschoolers, adolescents, and adults. School-age children exhibit increasing independence around health-related behaviors, which provide health professionals the opportunity to educate and promote healthy sleep behaviors. This commentary extends previous research reviews by identifying the current gaps in sleep research, highlighting future directions needed in sleep research, and explaining why school nurses are best suited to address this growing public health issue.

Integrative miRNA-mRNA profiling of adipose tissue unravels transcriptional circuits induced by sleep fragmentation

Obstructive sleep apnea (OSA) is a prevalent condition and strongly associated with metabolic disorders. Sleep fragmentation (SF) is a major consequence of OSA, but its contribution to OSA-related morbidities is not known. We hypothesized that SF causes specific perturbations in transcriptional networks of visceral fat cells, leading to systemic metabolic disturbances. We simultaneously profiled visceral adipose tissue mRNA and miRNA expression in mice exposed to 6 hours of SF during sleep, and developed a new computational framework based on gene set enrichment and network analyses to merge these data. This approach leverages known gene product interactions and biologic pathways to interrogate large-scale gene expression profiling data. We found that SF induced the activation of several distinct pathways, including those involved in insulin regulation and diabetes. Our integrative methodology identified putative controllers and regulators of the metabolic response during SF. We functionally validated our findings by demonstrating altered glucose and lipid homeostasis in sleep-fragmented mice. This is the first study to link sleep fragmentation with widespread disruptions in visceral adipose tissue transcriptome, and presents a generalizable approach to integrate mRNA-miRNA information for systematic mapping of regulatory networks.

Determining sleep quality in children with sleep disordered breathing: EEG spectral analysis compared with conventional polysomnography

STUDY OBJECTIVES

To identify the extent of sleep disruption in children with various severities of sleep disordered breathing (SDB) using both conventional visually scored assessment of sleep stages and arousal indices together with EEG power spectral analysis.

DESIGN

Sleep stages and power spectral analysis of the sleep EEG in children with varying severities of SDB with matched control subjects with no history of snoring were compared across the whole night, across sequential hours from sleep onset, and across sleep stages.

MEASUREMENTS

Overnight polysomnography was performed on 90 children (49M/41F) aged 7-12 y with SDB and 30 age-matched healthy controls (13M/17F). Sleep stages were visually scored and the EEG spectra were analyzed in 5-s epochs.

RESULTS

Conventional visual scoring indicated that, although sleep duration was reduced in severely affected children, sleep quality during the essential stages of SWS and REM was preserved, as evidenced by the lack of any significant decrease in their duration in SDB severity groups. This finding was supported by the lack of substantial differences in EEG spectral power between the groups over the whole night, within specific hours, and in individual sleep stages.

CONCLUSIONS

Both conventional scoring and EEG spectral analysis indicated only minor disruptions to sleep quality in children with SDB when assessed across the night, in any specific hour of the night, or in any specific sleep stage. These results suggest that reduced daytime functioning previously reported in children with SDB may not be due to sleep disruption. We speculate that in children, in contrast to adults, a stronger sleep drive may preserve sleep quality even in severe SDB.

[Snoring as an sign of sleep disorders in 11- to 15-year-old school children--initial results of a Vienna epidemiologic study]

INTRODUCTION

The prevalence of snoring was evaluated in school children between 11 and 15 years of age. In addition to items reported by parents, children were asked to answer a questionnaire in order to receive information about the children's potential complaints, life style and school performance.

METHOD

The study was performed in 21 randomly selected schools in the Vienna area. 1434 school children were interviewed by a questionnaire (mean age 12.5 years, median 13 years, 676 girls vs. 699 boys). The questionnaire consisted of 45 multiple-choice questions about the socioeconomic status, possible sleep disorders and signs or symptoms of obstructive sleep apneas (OSA). The questionnaire completed by parents was also used to calculate the Brouillette-Score from the items snoring, obstructed breaths and apneas.

RESULTS

5.2% (74/1434) of children and 6.9% (86/1259) of parents or caregivers reported about snoring (frequently or very frequently). There were no sex differences for the children's and the parents' questionnaire. None of the children had a clearly positive result (hint of OSA) from the Brouillette-Score whereas "suspicious OSA" was observed in 3.2% (40/1259). When frequent and very frequent snorers were compared with the other children, more mouth breathing during sleep (p < 0.00001), mouth dryness (p < 0.00005), headache (p < 0.0005), cigarette exposition at home (p < 0.001), smoking (p < 0.005), daytime naps (p < 0.005), crying out of sleep (p < 0.01), daytime tiredness (p < 0.05) und a higher body mass index (p < 0.05) could be observed in this group, in addition to the items reported by the parents.

CONCLUSION

The prevalence of snoring is lower in our study than in other studies. No statistically significant sex differences were observed, both in the parents' and the children's questionnaire. In our study snoring seems to be a sign or symptom of different sleep disorders, and not only of OSA. A statistically significant correlation between snoring and anamnestic hints of sleep disorders underlines the need to ask concerned children themselves for observations potentially associated with sleep disorders. Results of the Brouillette-Score could not be used to identify sleep disorders in our study.