Sleep-Disordered Breathing in Obese Children

In This Article

Abstract and Introduction

Abstract

Background: The association of obesity with sleep-associated respiratory disturbances, which has traditionally been described as a problem in adults, actually originates in childhood. We sought an association between sleep-disordered breathing (SDB) and overweight and/or obesity in a large cohort of school- and preschool-aged children in Southern Italy.
Methods: One thousand two hundred seven children (612 girls and 595 boys; mean age 7.3 years) were screened by self-administered questionnaires. According to answers, subjects were divided into three groups: nonsnorers (NS), occasional snorers (OS), and habitual snorers (HS). All HS, who also failed an oximetry study at home, underwent polysomnographic monitoring for the definition of SDB. BMI was calculated according to Italian growth charts.
Results: A total of 809 subjects (67.0%) were eligible for the study. Of them, 44 subjects (5.4%) were classified as HS, 138 (17.0%) as OS, and 627 (77.5%) as NS. Fourteen subjects (1.7%) were given a diagnosis of obstructive sleep apnea syndrome (OSAS). Sixty-four subjects (7.9%) were defined as obese, 121 (14.9%) as overweight, and 624 (77.2%) as normal weight. The frequency of HS was significantly higher in obese subjects than in overweight and normal-weight subjects (12.5% vs 5.8% vs 4.6%, respectively; P = .02), whereas the frequency of OSAS was 1.6% in normal-weight, 1.6% in overweight, and 3.1% in obese subjects (P = not significant).
Conclusions: Our findings in a large sample of Italian children suggest that obesity is associated with snoring.

Introduction

The interplay between obesity and respiratory function has implications for sleep-disordered breathing (SDB) in childhood. Horner et al^[1] have documented in adults that fatty infiltration of upper airway structures causes upper airway narrowing, whereas subcutaneous fat deposits in the anterior neck region and other cervical structures exert collapsing forces that promote increased pharyngeal collapsibility. Although a similar assessment of the airway structures and dynamics in obese children remains to be done, there is strong evidence to suggest that structural differences in upper airway dimension in combination with large tonsils and adenoids can make airway obstruction a significant concern in obese children. Moreover, obesity can affect ventilation through mass loading of the respiratory system.^[2,3] Increased adipose tissue in the abdominal wall and cavity, as well as that surrounding the thorax, reduces intrathoracic volume and diaphragm excursion, particularly in the supine position, and increases the work of breathing during sleep.^[4,5]

SDB exists in a continuous spectrum from snoring to severe obstructive sleep apnea syndrome (OSAS) and, because nearly all children affected by OSAS snore, it is necessary to distinguish between the two conditions. Primary snoring, a common finding in childhood, is not associated with the typical features of OSAS, such as apnea, oxygen desaturation, or hyperventilation, but it may precede complex SBD by many years.^[6,7] Epidemiologic data of SDB, and particularly OSAS, in childhood are limited;^[8–13] we have recently reported the prevalence of this condition in a large cohort of Italian children.^[14]

On the other hand, the prevalence of childhood obesity has risen worldwide over the last quarter century, especially in the United States,^[15] and, although not well studied, it can be assumed that the increased prevalence of obesity has also been accompanied by a rise in the incidence of SDB. The excess body fat in children is also associated with the earlier emergence of metabolic conditions, such as insulin resistance and type 2 diabetes mellitus, systemic hypertension, and dyslipidemia,^[16–20] and some authors have suggested the presence of a subclinical inflammation in overweight children with OSAS and have speculated that OSAS exacerbates the chronic inflammatory state that characterizes obese adipose tissue.^[21–24]

How childhood obesity is associated with SDB and what contribution the breathing disorder might play in maintaining obesity and increasing the risk of comorbidities are still debated among researchers worldwide.^[25–28] The available data on children do not support straightforward conclusions, mainly because of methodologic differences among studies conducted in different countries. In this cross-sectional study, we sought a relationship between overweight or obesity and sleep breathing disturbances in a large sample of children, using Italian thresholds for the identification of childhood SDB.

Cite this: Sleep-disordered Breathing in Obese Children: The Southern Italy Experience - Medscape - May 01, 2010.

Table 1. Distribution of the Study Population in Habitual Snorers, Occasional Snorers, and Nonsnorers by Gender
Gender	Snorers
Gender	NS	OS	HS
Boys	302	72	28
Girls	325	66	16

P value = not significant. HS = habitual snorers; NS = nonsnorers; OS = occasional snorers.

Table 2. Distribution of the Study Population in Habitual Snorers, Occasional Snorers, and Nonsnorers by BMI
BMI	Snorers
BMI	NS	OS	HS
Normal weight	489	106	29
Overweight	93	21	7
Obese	45	11	8

P value = not significant. See Table 1 for expansion of abbreviations.

Table 3. Distribution of the Study Population in Habitual Snorers and Occasional Snorers Plus Nonsnorers by BMI
BMI	Snorers
BMI	OS and NS	HS
Normal weight	595	29
Overweight	114	7
Obese	56	8

P value obese vs overweight vs normal weight = .02. See Table 1 for expansion of abbreviations.

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