A study investigating sleep apnea prevalence in 2- to 6-year-olds uncovers significant research roadblocks.

Interview by Alyx Arnett

A new systematic review raises concerns that obstructive sleep apnea (OSA) might be affecting an increasing number of preschool-aged children.

Solveig Magnusdottir, MD, MSc, MBA

The review aimed to uncover the prevalence of OSA among children ages 2 to 6, motivated by observations that factors such as the increased rates of obesity and air pollution might have contributed to more cases.

But an analysis of decades of research revealed a complex picture, muddied by inconsistent diagnostic methods and varying definitions. Diagnostic strategies of 30 studies ranged from parent-completed questionnaires to the sparing use of polysomnography (PSG). 

Study author Solveig Magnusdottir, MD, MSc, MBA, discussed the study with Sleep Review via email.

[Editor’s Note: Read the study, “Prevalence of obstructive sleep apnea (OSA) among preschool aged children in the general population: a systematic review,” in Sleep Medicine Reviews.]

What motivated the focus on the prevalence of OSA in preschool-aged children? 

Children develop rapidly, both physically and mentally during the preschool years. Healthy sleep, both in duration and quality, is important for optimizing children’s growth and development. Sleep apnea negatively affects the child’s sleep quality and has been associated with significant morbidities affecting behavior, neurocognitive development, and cardiovascular and cardiometabolic health

I wanted to better understand the prevalence of sleep apnea in population-based young children with one question: Should sleep evaluation be given more prominence during pediatric well-visits, as current evidence implies that health and quality of life improve with treatment of sleep apnea at a young age? I started with a literature search, which did not give me good information on the prevalence of sleep apnea in young children, so I decided to do this systematic review. 

What were your main findings? 

Data looking at the prevalence of sleep apnea in young children is not of a high quality. There was a high degree of heterogeneity in methods and definitions in the studies. Most are based on only utilizing sleep questionnaires and not confirming OSA with objective testing (23 of 30 studies), and not all the studies are even utilizing validated sleep questionnaires. 

Of the seven studies that started by screening for habitual snoring with sleep questionnaires and then referring children with habitual snoring for objective testing, only two used PSG,  and in only 1.2% of their combined cohorts (n=82/4,575). 

Additionally, all the studies based their sleep apnea diagnosis on retired thresholds of the apnea-hypopnea index (AHI). AHI4% five/hour of sleep is not the current reference standard of AHI3% one/hour of sleep.

Were there any surprising findings?

The paucity of research looking at sleep apnea in preschoolers during the last decade and the lack of quality data. 

The studies utilizing some objective evaluations were conducted before 2004, except one published in 2016. With the advancements in technology, I would have expected to see more studies in recent years confirming the outcome of sleep questionnaires for evaluation with objective testing. 

There was not one study in this age group that started screening their cohort with a validated sleep questionnaire and then referred the whole cohort for testing. This is quite important as a recent systematic review evaluating the accuracy of sleep questionnaires to identify sleep apnea when compared to PSG outcomes in older children found that the two most accurate sleep questionnaires correctly identified only 76% and 56% of children with sleep apnea.

Studies published before 2014 reported 3.3% to 9.4% prevalence, higher than what has been commonly referenced, 1% to 4%. More recent studies published from 2016 to 2023 report higher prevalence, 12.8% to 20.4% when excluding outliers, a trend suggesting that the prevalence of OSA may possibly have been increasing over the past decade. 

With the relationship between obesity and sleep apnea and the increase seen in obesity during the last decade, this is not an unlikely development.

How should the approach to diagnosing OSA in children be reevaluated?

With the relatively low sensitivity of validated sleep questionnaires to identify sleep apnea in children, and because children are a vulnerable population, there is a need to address sleep in children with more accurate measures. 

The method currently promoted to evaluate sleep apnea in children is PSG, which is problematic. Diagnosis of OSA using PSG is routinely based on a single night of sleep in a foreign environment, which arguably puts the diagnostic accuracy in question because of night-to-night variability in sleep and respiratory parameters. 

As younger children with sleep apnea are more likely to demonstrate improvements in neurocognitive outcomes with therapy than older children, accurate early identification and appropriate therapy are important. Therefore, repeated testing using simpler methods that objectively measure sleep and respiration in the child’s sleeping environment is the only realistic first choice in a process to evaluate and diagnose sleep apnea in children based on the complexity, inaccessibility, and high cost of PSG studies.

Furthermore, when reviewing the research data looking at sleep apnea in young children, it may be debatable whether PSG should be considered the reference standard for diagnosing sleep apnea in young children as that status is not supported by scientific evaluation of clinical evidence from available research. 

How do your results inform clinical practice?

To improve clinical diagnosis and management of sleep apnea in young children, the clinical pathway should benefit from adding objective multi-night sleep testing to current protocols of sleep questionnaires and clinical evaluation. This type of evaluation should better address the need for sleep apnea treatment and inform the optimal timing of intervention. 

Having clinically relevant, simple-to-use, low-cost options to objectively evaluate sleep for multiple nights will also capture the night-to-night variability in sleep apnea and, when performed in the child’s natural sleep environment, should add to the diagnostic credibility and empower physicians with data that would support improved precision of sleep apnea diagnosis and treatment tracking.

What further research should be done? 

Future studies focusing on the prevalence of sleep apnea in young children need to implement not only validated sleep questionnaires in the whole cohort but also objective testing recording sleep and respiratory parameters for more than one night to capture intra-night-variability. 

Some children with sleep apnea have no history of snoring reported by parents, or parents may not be paying attention to identify their child as “suspect of sleep apnea.” Therefore, these children have not been included in objective testing in the current literature, possibly resulting in an underestimation of the prevalence of sleep apnea. 

Future studies also need to include standardized pediatric-specific diagnostic criteria and thoroughly report on comorbid conditions that may affect sleep apnea prevalence.

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