Identification of obstructive sleep apnea in children with obesity: A cluster analysis approach

BACKGROUND

Obstructive sleep apnea (OSA) is a heterogeneous disorder with a prevalence of 25%-60% in children with obesity. There is a lack of diagnostic tools to identify those at high risk for OSA.

METHOD

Children with obesity, aged 8-19 years old, were enrolled into an ongoing multicenter, prospective cohort study related to OSA. We performed k-means cluster analysis to identify clinical variables which could help identify obesity related OSA.

RESULTS

In this study, 118 participants were included in the analysis; 40.7% were diagnosed with OSA, 46.6% were female and the mean (SD) body mass index (BMI) and age were 39.7 (9.6) Kg/m², and 14.4 (2.6) years, respectively. The mean (SD) obstructive apnea-hypopnea index (OAHI) was 11.0 (21.1) events/h. We identified two distinct clusters based on three clustering variables (age, BMI z-score, and neck-height ratio [NHR]). The prevalence of OSA in clusters 1 and 2, were 22.4% and 58.3% (p = 0.001), respectively. Children in cluster 2, in comparison to cluster 1, had higher BMI z-score (4.7 (1.1) versus 3.2 (0.7), p < 0.001), higher NHR (0.3 (0.02) versus 0.2 (0.01), p < 0.001) and were older (15.0 (2.2) versus 13.7 (2.9) years, p = 0.09), respectively. However, there were no significant differences in sex and OSA symptoms between the clusters. The results from hierarchical clustering were similar to k-means analysis suggesting that the resulting OSA clusters were stable to different analysis approaches.

INTERPRETATION

BMI, NHR, and age are easily obtained in a clinical setting and can be utilized to identify children at high risk for OSA.

Associations between body mass index, sleep-disordered breathing, brain structure, and behavior in healthy children

Pediatric overweight/obesity can lead to sleep-disordered breathing (SDB), abnormal neurological and cognitive development, and psychiatric problems, but the associations and interactions between these factors have not been fully explored. Therefore, we investigated the associations between body mass index (BMI), SDB, psychiatric and cognitive measures, and brain morphometry in 8484 children 9-11 years old using the Adolescent Brain Cognitive Development dataset. BMI was positively associated with SDB, and both were negatively correlated with cortical thickness in lingual gyrus and lateral orbitofrontal cortex, and cortical volumes in postcentral gyrus, precentral gyrus, precuneus, superior parietal lobule, and insula. Mediation analysis showed that SDB partially mediated the effect of overweight/obesity on these brain regions. Dimensional psychopathology (including aggressive behavior and externalizing problem) and cognitive function were correlated with BMI and SDB. SDB and cortical volumes in precentral gyrus and insula mediated the correlations between BMI and externalizing problem and matrix reasoning ability. Comparisons by sex showed that obesity and SDB had a greater impact on brain measures, cognitive function, and mental health in girls than in boys. These findings suggest that preventing childhood obesity will help decrease SDB symptom burden, abnormal neurological and cognitive development, and psychiatric problems.

Intermittent Hypoxia and Diet-Induced Obesity on the Intestinal Wall Morphology in a Murine Model of Sleep Apnea

This work analyzes the impact of two conditions, intermittent hypoxia exposure and high-fat diet in rats as models of sleep apnea. We studied the autonomic activity and histological structure of the rat jejunum and whether the overlapping of both conditions, as often observed in patients, induces more deleterious effects on the intestinal barrier. We found alterations in jejunum wall histology, predominantly in HF rats, based on increased crypt depth and submucosal thickness, as well as decreased muscularis propria thickness. These alterations were maintained with the IH and HF overlap. An increase in the number and size of goblet cells in the villi and crypts and the infiltration of eosinophils and lymphocytes in the lamina propria suggest an inflammatory status, confirmed by the increase in plasma CRP levels in all experimental groups. Regarding the CAs analysis, IH, alone or combined with HF, causes a preferential accumulation of NE in the catecholaminergic nerve fibers of the jejunum. In contrast, serotonin increases in all three experimental conditions, with the highest level in the HF group. It remains to be elucidated whether the alterations found in the present work could affect the permeability of the intestinal barrier, promoting sleep apnea-induced morbidities.

Effect of Continuous Positive Airway Pressure on Weight and Local Adiposity in Adults with Obstructive Sleep Apnea: A Meta-Analysis

Rationale: Evidence suggests that continuous positive airway pressure (CPAP) treatment promotes weight gain in patients with obstructive sleep apnea (OSA). It is unclear whether weight gain is influenced by CPAP adherence or comorbid disorders. Objectives: To examine the CPAP effects on body mass index (BMI) and local adiposity and the potential moderators of CPAP effects on BMI in patients with OSA. Methods: We searched PubMed/Medline, Embase, and Cochrane through December 2019. Randomized controlled trials of CPAP versus control treatment with ⩾4 weeks' treatment were included. Results: A total of 39 randomized controlled trials with 6,954 subjects were included. In intention-to-treat analysis, the BMI increased significantly after CPAP treatment compared with control treatment (weighted mean difference [WMD], 0.148 kg/m²; 95% confidence interval, 0.04-0.26; P = 0.001). In studies demonstrating an increase in the BMI, waist and neck circumferences were also significantly increased. Subgroup analyses revealed that an increased BMI was attributable to CPAP use of ⩽5 h/night (WMD, 0.231) but was not attributable to CPAP use of >5 h/night (WMD, 0.001; between-group P value = 0.049). Furthermore, the BMI increased significantly in patients without cardiovascular disease (CVD; WMD, 0.200), whereas it decreased significantly in those with CVD at baseline (WMD, -0.188; between-group P value < 0.001). Moreover, the BMI increased significantly in patients with dysglycemia (WMD, 0.499) but did not increase in those without dysglycemia at baseline (WMD, 0.100; between-group P value = 0.032). Meta-regression confirmed the subgroup findings. Conclusions: The BMI increased significantly in patients with OSA after CPAP treatment, especially in those with CPAP use of ⩽5 h/night, without CVD and/or with dysglycemia at baseline. CPAP use of at least 5 h/night seems to be necessary in mitigating the risk for weight gain in patients with OSA.

Obstructive sleep apnoea/hypopnoea syndrome: relationship with obesity and management in obese patients

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is a disease characterised by upper airway obstruction during sleep, quite frequent in the general population, even if underestimated. Snoring, sleep apnoea and diurnal hypersomnia are common in these patients. Central obesity plays a key role: it reduces the size and changes the conformation of the upper airways, besides preventing lung expansion, with consequent reduction of lung volumes. Furthermore, obese people are also resistant to leptin, which physiologically stimulates ventilation; as a result, this causes scarce awakening during apnoea. OSAHS diagnosis is based on the combination of clinical parameters, such as apnoea/hypopnoea index (AHI), medical history, physical examination and Mallampati score. The first objective reference method to identify OSAHS is polysomnography followed by sleep endoscopy. Therapy provides in the first instance reduction of body weight, followed by continuous positive airway pressure (CPAP), which still remains the treatment of choice in most patients, mandibular advancement devices (MAD) and finally otolaryngology or maxillofacial surgery. Among surgical techniques, central is barbed reposition pharyngoplasty (BRP), used in the field of multilevel surgery.

Characteristics of factors for decreased lung function in elderly patients with type 2 diabetes

Chronic obstructive pulmonary disease (COPD) often accompanies type 2 diabetes mellitus (T2DM). However, background factors affecting these diseases in the elderly remain unclear. Eligible patients with T2DM were divided into two age groups—non-elderly (<65 years) and elderly (≥65 years); COPD, ratio of forced expiratory volume in one second to forced expiratory volume (FEV1/FVC ratio), and percent predicted forced expiratory volume in one second (FEV1% predicted) were examined, and factors related to reduced respiratory function according to age group were evaluated. In total, 371 patients with T2DM were analysed. COPD was found in 9 patients (5.3%) in the non-elderly group and 45 (22.5%) in the elderly group. In the elderly, male sex, low body mass index (BMI), insulin therapy, and high C-peptide immunoreactivity levels were factors related to COPD. In the non-elderly, age, female sex, high BMI were factors related to decreased FEV1% predicted. Female sex was factor related to decreased FEV1% predicted in both age groups. Low BMI was a factor related to reduced respiratory function in elderly patients and high BMI was a factor related to reduced respiratory function in non-elderly patients. Thus, BMI needs to be managed according to the age and general condition of T2DM patients.

Obesity hypoventilation syndrome in the critically ill

This article summarizes available data on the obesity hypoventilation syndrome and its pertinence to intensivists, outlines clinical and pathophysiologic aspects of the disease, discusses multidisciplinary treatments, and reviews the available literature on outcomes specific to the critically ill patient.

Obesity and sleep-disordered breathing--when two 'bad guys' meet

Sleep-disordered breathing (SDB), in particular obstructive sleep apnoea (OSA) and obesity hypoventilation syndrome (OHS) are associated with significant morbidity and mortality. The prevalence of these conditions is rapidly rising mainly due to the worldwide increase in obesity. Obesity contributes to the pathogenesis of SDB in multiple ways including altering upper airway anatomy and collapsibility, ventilatory control and increasing respiratory work load. There is also increasing evidence that OSA itself contributes to the development of obesity. Moreover, both OSA and obesity promote the activation of inflammatory pathways, which is likely a key mechanism in cardiovascular and metabolic disease processes. Early recognition of SDB is important as effective treatments are available. Public health measures to reduce the prevalence of obesity are urgently required to halt the increasing burden of SDB.

Respiratory mechanics and ventilatory control in overlap syndrome and obesity hypoventilation

The overlap syndrome of obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease (COPD), in addition to obesity hypoventilation syndrome, represents growing health concerns, owing to the worldwide COPD and obesity epidemics and related co-morbidities. These disorders constitute the end points of a spectrum with distinct yet interrelated mechanisms that lead to a considerable health burden. The coexistence OSA and COPD seems to occur by chance, but the combination can contribute to worsened symptoms and oxygen desaturation at night, leading to disrupted sleep architecture and decreased sleep quality. Alveolar hypoventilation, ventilation-perfusion mismatch and intermittent hypercapnic events resulting from apneas and hypopneas contribute to the final clinical picture, which is quite different from the “usual” COPD. Obesity hypoventilation has emerged as a relatively common cause of chronic hypercapnic respiratory failure. Its pathophysiology results from complex interactions, among which are respiratory mechanics, ventilatory control, sleep-disordered breathing and neurohormonal disturbances, such as leptin resistance, each of which contributes to varying degrees in individual patients to the development of obesity hypoventilation. This respiratory embarrassment takes place when compensatory mechanisms like increased drive cannot be maintained or become overwhelmed.

Although a unifying concept for the pathogenesis of both disorders is lacking, it seems that these patients are in a vicious cycle. This review outlines the major pathophysiological mechanisms believed to contribute to the development of these specific clinical entities. Knowledge of shared mechanisms in the overlap syndrome and obesity hypoventilation may help to identify these patients and guide therapy.

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.

Positive pressure for obesity hypoventilation syndrome

Obesity is increasing world-wide; obesity hypoventilation syndrome (OHS), formerly Pickwickian syndrome, has increased in parallel. Despite its prevalence, OHS has not been studied well, but there is abundant evidence that it is tightly linked with sleep-disordered breathing, most commonly obstructive sleep apnea. This article reviews the pathophysiology of OHS as well as the literature regarding the benefits of treating this disorder with positive airway pressure. We also emphasize that while positive pressure treatments may temporize cardiopulmonary disease progression, simultaneous pursuit of weight reduction is central to long-term management of this condition.

The reciprocal interaction between obesity and obstructive sleep apnoea. Sleep Med Rev. 2013;17:123-131. [PMID: 22818968 DOI: 10.1016/j.smrv.2012.05.002]

Obesity is a significant risk factor in the pathogenesis of obstructive sleep apnoea (OSA) altering airway anatomy and collapsibility, and respiratory control. The association between obesity and OSA has led to an increasing focus on the role of weight loss as a potential treatment for OSA. To date, most discussion of obesity and OSA assumes a one-way cause and effect relationship, with obesity contributing to the pathogenesis of OSA. However, OSA itself may contribute to the development of obesity. OSA has a potential role in the development and reinforcement of obesity via changes to energy expenditure during sleep and wake periods, dietary habits, the neurohormonal mechanisms that control satiety and hunger, and sleep duration arising from fragmented sleep. Thus, there is emerging evidence that OSA itself feeds back into a complex mechanism that leads either to the development or reinforcement of the obese state. Whilst current evidence does not confirm that treatment of OSA directly influences weight loss, it does suggest that the potential role OSA plays in obesity and weight loss deserves further research.

Obstructive sleep apnea (OSA) does not affect ventilatory and perceptual responses to exercise in morbidly obese subjects

We have tested the hypothesis that high mass loading effects and obstructive sleep apnea (OSA) constrain the ventilatory response to exercise in morbidly obese subjects as compared to their counterparts without OSA. Fifteen obese patients with (8) and without OSA and 12 lean healthy subjects performed incremental cycle exercise. The functional evaluation included ventilation, oxygen uptake, carbon dioxide production, end-expiratory-lung-volumes (EELV), inspiratory capacity, heart rate, dyspnea and leg effort (by a modified Borg scale). Changes in ventilation and dyspnea per unit changes in work rate and metabolic variables were similar in the three groups. Breathing pattern and heart rate increased from rest to peak exercise similarly in the three groups. Leg effort was the prevailing symptom for stopping exercise in most subjects. In conclusion, OSA does not limit exercise capacity in morbidly obese subjects. Ventilation contributes to exertional dyspnea similarly as in lean subjects and in obese patients regardless of OSA.