Elsevier

Sleep Medicine

Volume 82, June 2021, Pages 29-36
Sleep Medicine

Original Article
Factors associated with referral for polysomnography in children with Down syndrome

https://doi.org/10.1016/j.sleep.2021.03.019Get rights and content

Highlights

  • Two-thirds of those recruited from the community had obstructive sleep apnea (OSA).

  • 79% of the community group had never had polysomnography.

  • Severity of OSA was not different between the referred and community groups.

  • More children in the group referred for polysomnography were obese.

  • Behavior and quality of life were not different between the two groups.

Abstract

Objectives

Children with Down syndrome (DS) are recommended to undergo polysomnography (PSG) by the age of four years due to the high prevalence of obstructive sleep apnea (OSA) in this group, but compliance is incomplete. To further understand referral patterns for PSG in this condition, we aimed to compare demographics, PSG results, OSA severity, behavior, daytime functioning and quality of life (QOL) between children with DS referred for sleep testing and those recruited from the community.

Study design

Children 3–19 years with DS was included: 20 referred clinically for assessment of OSA and 24 volunteers from the community. Demographic and anthropometric data, PSG parameters, sleep-related symptoms and QOL, behavior and daytime functioning were compared between groups.

Results

OSA severity did not differ between groups: 50% of the clinical and 42% of the community group had moderate/severe OSA. The clinical group had a higher weight z-score, BMI z-score, waist and hip circumference and neck-to-waist ratio. Questionnaire scores for daytime functioning, behavior and QOL were not different between groups.

Conclusions

Despite not being referred for clinical sleep assessment, 42% of children with DS recruited from the community had moderate/severe OSA. There was no difference in the QOL, behavior, daytime functioning and sleep symptoms questionnaires although the clinical group had a higher BMI-Z score and overt signs of obesity. These findings underscore the importance of PSG screening of all children with DS.

Introduction

Down syndrome (DS) is the most common human chromosomal abnormality, characterized by an extra copy of chromosome 21 [1,2]. The global incidence is estimated to be 1 in 700–1000 live births [3]. The rate of live births of children with DS is increasing, paralleling the increase in births to women aged over 35 years [4].

Obstructive sleep apnea (OSA) is the most commonly reported sleep disorder in children with DS [5,6]. OSA is characterized by repeated episodes of upper airway obstruction during sleep with resultant hypoxia, hypercapnia and/or sleep disturbance. Craniofacial abnormalities, including midface and mandibular hypoplasia, hypotonia and glossoptosis contribute to the predisposition for OSA in children with DS [7,8]. Children with DS are also more prone to obesity and reduced muscle tone, which can further compromise airflow through the upper airway.

The prevalence of OSA is reported to be less than 6% in typically developing (TD) children [9], whereas the prevalence of OSA in children with DS ranges from 66% to over 90% in clinical populations [[10], [11], [12]] and between 31% and 61% in non-clinically referred community populations [13,14]. This wide range in the reported prevalence of OSA may be due to different diagnostic methods, varying population sizes and also differences in the ages of the studied children.

Several studies have demonstrated that OSA contributes to difficulties in cognition, behavior and daytime functioning in TD children [[15], [16], [17]] and in children with DS [[18], [19], [20]]. Due to the high prevalence and potential for significant daytime impacts, the American Academy of Pediatrics (AAP) recommends routine polysomnography (PSG) for the detection of OSA in children with DS by the age of four years [2]. Despite this recommendation, nearly a third of children with DS do not undergo a PSG study in that time frame [21]. We have previously shown that children with DS referred for assessment of OSA had more severe OSA compared to a cohort of referred TD children without any major comorbidities [10], suggesting a difference in threshold or triggers for referral for PSG.

The aims of this study were to assess whether there was a difference in OSA severity between children with DS recruited from the community compared to children with DS who present clinically and whether there were differences in clinical factors, sleep, behavior, daytime functioning and quality of life (QOL) that might have triggered referral for testing. We hypothesized that children with DS from the community would exhibit lower OSA severity compared to clinically referred children with DS. However, we anticipated that other sleep and behavioral problems would be more evident in the clinical group which may have motivated parents or doctors to undertake investigation of their child's sleep.

Section snippets

Methods

Ethical approval for this study was granted by the Monash Health and Monash University Human Research Ethics Committees. Written informed consent was obtained from parents.

A total of 44 children aged between 3 and 19 years with DS were recruited from two sources: those clinically referred for assessment of OSA (n = 20) and children recruited from the community (n = 24), via publicity by Down Syndrome Victoria. The publicity material for the study included that the study was about sleep and

Demographics

A total of 44 children participated in this study: 20 children 13 females (60%); median age, 10.4 years (IQR 5.8–14.5 years, range 3.0–17.1 years) were referred to the Sleep Clinic and 24 children 12 females (50%); median age, 7.0 years (IQR 4.5–8.9 years, range 3.7–19.1 years) were recruited from the community. In the community group, 19 children (79%) had never previously undergone a PSG study. Of the remaining five children, three children had one previous PSG before the age of four years.

Discussion

This is the first study to compare laboratory based PSG results and parental questionnaires of sleep, QOL, daytime functioning and behavior between children with DS who were clinically referred for assessment of OSA and a sample of children from the community. Contrary to our hypothesis we found that the presence and severity of OSA was not different between groups and whilst many children scored outside the clinical threshold on parental reports of measures of quality of life, behavior,

Funding sources

This project was supported by the Angior Family and Jack Brockhoff Foundations.

Author credit statement

Poornima R. Wijayaratne: Investigation, Formal analysis, Data curation, Writing – Original draft preparation, Writing – Review & Editing. Katrina Williams: Conceptualisation/Design, Supervision, Resources, Writing – Review & Editing. Margot Davey: Resources, Writing – Review & Editing. Rosemary Horne: Conceptualisation/Design, Methodology, Supervision, Investigation, Data curation, Funding acquisition, Resources, Writing – Review & Editing. Gillian Nixon: Conceptualisation/Design, Methodology,

Acknowledgements

The authors wish to acknowledge the assistance of Dr Lisa Walter and Mr Aidan Weichard for assistance in data collection. We would also like to thank all the parents and their children who participated in the study and the staff of the Melbourne Children's Sleep Centre, where the study was carried out. This project was supported by the Angior Family and Jack Brockhoff Foundations.

Abbreviations and Acronyms

AAP
American Academy of Pediatrics
ABAS
Adaptive Behavior Assessment Scheme
ArI
Arousal index
BMI
Body mass index
CBCL
Child Behavior Checklist
CnAHI
Central apnea hypopnea index
DS
Down syndrome
ESS-CHAD
Epworth Sleepiness Scale for Children and Adolescents
IQR
Interquartile range
NREM
Non-rapid eye movement
OAHI
Obstructive apnea hypopnea index
ODI
Oxygenation desaturation index
OSA
Obstructive Sleep Apnea
PSG
Polysomnography
PSSI
Pediatric Sleep Survey Instrument
QOL
Quality of life
RDI
Respiratory disturbance index
REM
Rapid

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