ORIGINAL ARTICLEPulmonary function and sleep-related breathing disorders in severely obese children
Introduction
The prevalence of childhood obesity is increasing at an alarming rate in western countries resulting from an interaction between environmental factors and genes.1, 2 Childhood obesity is associated with morbidity and significant risk for the development of cardiovascular and related diseases in later life,3, 4 justifying the necessity to detect such complications as early as possible.
In obese adults, both pulmonary function and sleep-breathing disorders are well known and are related to the severity of obesity.5 The most frequently reported abnormalities in pulmonary function are reductions in lung volumes and expiratory flow rates, mainly caused by the mass of visceral fat, which show positive results following weight loss.6 Sleeping disorders such as obstructive sleep apnoea (OSA) in obese adults are also a major problem because of increased cardiovascular and cerebrovascular morbidity.7 Development of OSA is multifactorial, including body fat distribution, sex, and structural differences in upper airway dimensions.8, 9 There is also a link between OSA and insulin resistance,10 and hyperleptinaemia is associated with OSA in obese adult patients independently of body mass index (BMI) suggesting a role of leptin resistance in obesity-related breathing disorders.11
For children, the few studies that have evaluated the effect of obesity on pulmonary function have showed conflicting results. Reductions in functional residual capacity (FRC) and impaired diffusion have been described as the commonest abnormalities in obese children, with a correlation between the reduction in static lung volume and the degree of obesity.12 However, others found that obstructive abnormalities were the main problem, while some studies did not detect significant pulmonary disorders.13, 14 These conflicting results justify the necessity to explore pulmonary function in obese children to clarify the frequency and nature of such disorders.
OSA episodes are prevalent in obese children, but they are less severe than in adults.13, 15, 16, 17, 18, 19 As in adults, the risk of developing OSA increases with the severity of obesity and is related to complications such as behavioural problems, learning difficulties, inhibition in normal growth patterns, cardiovascular abnormalities (elevated diastolic blood pressure)20 and even insulin resistance.17 However, in the absence of specific symptoms related to OSA except for snoring, such disorders could be underestimated in obese children with potential long-term consequences during later life, especially in the absence of specific therapeutic measures such as adenotonsillectomy or continuous positive airway pressure (CPAP).21 In addition, the mechanisms inducing OSA in obese children are unknown except for the severity of obesity, as in adults, justifying the necessity to evaluate such disorders in obese children. Furthermore, only two studies have evaluated both pulmonary and nocturnal functions in the same group of such children.13, 16
The aim of our study was to evaluate the frequency of pulmonary function and sleep-breathing disorders in a cohort of severely obese children and to evaluate their association with clinical symptoms related to OSA, to the severity of obesity, to fat-mass repartition, and to metabolic complications.
Section snippets
Study population
Fifty-four children with severe obesity were recruited consecutively and prospectively at our Outpatient Department of Paediatric Nutrition from 2002 to 2004 (Table 1). Severe obesity was defined as a BMI Z-score>3 SD over mean age- and sex-specific BMI values determined in French children by Rolland-Cachera.22 Patients with syndromic obesity such as Prader–Willi or Laurence–Moon–Biedl syndromes, were excluded. All included patients were recruited for severe obesity with or without nocturnal
Patient characteristics
Results of anthropometry, body composition and laboratory tests are shown in Table 1. Thirty-six patients were Caucasians (67%) and 18 Blacks (33%). Thirteen patients were prepubertal (26%) and 37 pubertal (74%). Concerning clinical symptoms, 23% of the patients had morning headaches, 33% reported diurnal somnolence, 53% had nocturnal agitation with nocturnal perspiration in 42% of cases, 77% had a history of snoring, and 19% had a previous history of asthma.
Pulmonary studies
Pulmonary studies were performed for
Discussion
We evaluated the frequency of pulmonary function and sleep-breathing disorders in this cohort of severely obese children and searched for their association with specific phenotypes related to obesity. We found that both were already frequent in severely obese children, and that impaired respiratory conductance in upper airways was the main factor related to OSA in severely obese children.
In this study, we showed that OSA was a major concern in these obese children. We used an REI threshold>10
Acknowledgements
We thank Yves Lebouc and his staff (Endocrinology Laboratory, Armand-Trousseau Hospital) for performing the plasma glucose, insulin, and leptin measurements.
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2021, Archives de PediatrieCitation Excerpt :This result could be due to the small effect in each group. Reduction in plethysmographic functional residual capacity (FRC) is the most consistently reported effect of obesity on lung function, particularly in morbidly obese children [4,23]. Correlations between BMI z-score and reduction of FRC are not unanimously consistent in the literature.
Inhaled albuterol increases estimated ventilatory capacity in nonasthmatic children without and with obesity
2021, Respiratory Physiology and NeurobiologyCitation Excerpt :It is also unknown if an increase in FEF25−75 with a bronchodilator could have an important impact on estimated ventilatory capacity between 25 and 75 % of vital capacity (V̇Ecap25−75), especially in children with obesity, whose breathing mechanics may be altered at rest and during exercise. In children with obesity, extra weight on the chest wall reduces functional residual capacity (FRC) at rest and end-expiratory lung volume (EELV) during exercise to a point that is closer to residual volume (RV) where maximal expiratory flow is lowest (Dubern et al., 2006; Mendelson et al., 2012; Davidson et al., 2014) and expiratory flow limitation (EFL, an indicator of ventilatory limitation) is more likely to occur (Gibson et al., 2014; Mendelson et al., 2012). For example, FRC was reduced by 30 % (p < 0.05) in a group of adolescent children with obesity, when compared with their normal weight counterparts (Mendelson et al., 2012).
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