Obese Obstructive Sleep Apnea Syndrome Research Articles

Assessment of cephalometric parameters and correlation with the severity of the obstructive sleep apnea syndrome.

In individuals diagnosed with obstructive sleep apnea syndrome (OSAS), variations in craniofacial structure have been inconsistently documented, showing differing degrees of alteration between obese and nonobese patients. In addition, sleep disturbance has also been shown to induce disequilibrium in this population of patients. This pilot observational study aimed to assess craniofacial values in obese and nonobese subpopulations of patients with OSAS and their correlation and association with the severity of OSAS. We also assessed whether OSAS patients are characterized by an impaired equilibrium in relation to and associated with the severity of OSAS. We included all consecutive adult patients with OSAS. Through cephalometry, we assessed the upper (UPa-UPp) and lower (LPa-LPp) pharynx diameters, superior anterior facial height (Sor-ANS), anterior facial height (ANS-Me), anterior vertical dimension (Sor-Me), posterior facial height (S-Go) and craniovertebral angle (CVA). Furthermore, we analyzed postural equilibrium through a stabilometric examination. Forty consecutive OSAS patients (45% female with a mean age of 56 ± 8.2years) were included. The subgroup of nonobese patients had a reduced UPa-UPp (p = 0.02). Cephalometric measurements were correlated with the severity of OSAS in nonobese patients, whereas only Sor-ANS was correlated with the severity of OSAS in the obese subpopulation. In the overall population, altered craniofacial values are associated with severe OSAS. Although there are differences in equilibrium between obese and nonobese OSAS patients, the stabilometric measurements were not correlated or associated with OSAS severity. Altered craniofacial values and compromised equilibrium in OSAS patients are linked to OSAS severity. Therefore, the management of OSAS should be tailored not only to weight management but also to craniofacial and postural rehabilitation to enhance patient outcomes.

Small airway resistance in obese and nonobese patients with obstructive sleep apnea syndrome using impulse oscillometry.

There is limited information on the pathologic changes in the small airways among obese and nonobese patients with obstructive sleep apnea syndrome (OSAS). Impulse oscillometry (IOS) measures airway resistance and reactance independently of patient effort. This study aimed to compare airway resistance in small airways using IOS between obese and nonobese patients with OSAS. In this real-life cross-sectional study, demographic information was collected from obese and nonobese subjects diagnosed with moderate and severe OSAS without any other underlying diseases. Spirometry and IOS measurements were conducted, and the values of both groups were statistically analyzed. The nonobese group had a mean age of 45.6 ± 11.7 years (median 45), while the obese group had a mean age of 48.4 ± 9.5 years (median 47.5). The mean body mass index (BMI) for the nonobese group was 26.2 ± 2.1 kg/m2 (median 27 kg/m2), and for the obese group, it was 35.6 ± 6.4 kg/m2 (median 33 kg/m2). Statistically significant differences were observed between the two groups in R5 - R20 percentage, reactance area (AX), and resonant frequency (Fres) values (p < 0.05). Among obese OSAS patients, there is an increase in resistance in small airways as indicated by IOS values. IOS shows promise as a potential screening tool for diagnosing OSAS.

Obstructive sleep apnea syndrome in obese, non-obese and control children

Obstructive sleep apnea syndrome (OSAS) in children is a highly prevalent disorder. Adenotonsillectomy is considered the first line of treatment. The aim of this study is to assess the effect of adenotonsillectomy on the apnea-hypopnea index (AHI), on the cephalometric values and on arch width measurements in obese and non-obese children with OSAS, and to compare the arch width measurements with a control group. A quasi-experimental prospective study was performed. Children aged between 2 and 12 years were recruited. The sample was divided into three groups: 1. Obese children with OSAS (n=15), 2. Non-obese children with OSAS (n=117), 3. Matched control group (n=106). A child was considered obese when the body mass index was higher than 95 th percentile. All subjects underwent anthropometric measurements and alginate impressions. A polysomnography and teleradiography were taken only in both experimental groups. These records were also taken after one year. Kruskal-Wallis and Wilcoxon test were used to compare the quantitative variables. Regarding the arch width variables, there were statistically significant differences (p-value <0.05) between both OSAS group and control group. However, there were no statistically significant differences between the cephalometric and arch width variables between obesity and non-obesity group. After adenotonsillectomy AHI improved in non-obese OSAS group (p-value <0.001), but no statistical differences in AHI were found in the obese OSAS group. The dentofacial characteristics were similar in both obese and non-obese OSAS children. However, adenotonsillectomy improved the AHI in non-obese children more than in obese children.

Continuous Positive Airway Pressure Improves Renal Function in Obese Patients With Obstructive Sleep Apnea Syndrome.

Background: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular morbidity and mortality, and it has a detrimental effect on renal function. Obesity is the major risk factor for OSAS, and represents a risk factor for chronic kidney disease. Continuous positive airway pressure (CPAP) is the suggested therapy for moderate-to-severe OSAS. We designed this study to evaluate the effect of CPAP on estimated glomerular filtration rate (e-GFR) in a cohort of obese patients with moderate-to-severe OSAS and normal renal function.Methods: We enrolled 198 obese subjects, divided into two groups (OSAS+ and OSAS–), on the basis of cardiorespiratory monitoring; mild OSAS patients (n = 33) were excluded from the study, thus the analyses were conducted on 165 patients. Comparisons between groups were made by Student t-test or χ2 test as appropriate. Linear regression analyses were used to assess the relationship between baseline e-GFR and different covariates and, in the OSAS+ group, between Δe-GFR and different covariates. A multivariate regression analysis was performed to determinate the independent predictor of the Δe-GFR.Results: OSAS+ subjects showed significantly increased values of systolic blood pressure, HOMA, pulse wave velocity, high-sensitivity C reactive protein and uric acid compared with OSAS– group. OSAS+ group showed significantly lower values of e-GFR and increased values of microalbuminuria. At linear regression analysis e-GFR resulted significantly and inversely related to AHI in the whole study population and in the two groups. After 6 months of CPAP therapy, OSAS+ subjects showed an improvement in respiratory parameters, as well as a significant increase in e-GFR values (104.2 + 19.0 vs. 84.0 + 13.1 ml/min/1.73 m2, P < 0.0001). At multiple regression analysis, Δ apnea/hypopnea index (AHIa) resulted the main independent predictor of Δe-GFR explaining 22% of its variation.Conclusions: Obese OSAS patients show significantly lower values of e-GFR, even if in the normal range, compared with obese non-OSAS subjects. After 6 months of CPAP, e-GFR significantly improved (+20 ml/min/1.73 m2) and ΔAHIa resulted the most important independent predictor of Δe-GFR.

Positive airway pressure normalizes glucose metabolism in obstructive sleep apnea independent of diabetes and obesity

The relationship among obstructive sleep apnea syndrome (OSAS), type 2 diabetes mellitus (DM2) and obesity is very complex and multi-directional. Obesity and increased visceral fat are important perpetuating factors for DM2 in patients with OSAS. On the other hand, OSAS itself leads to obesity by causing both leptin and insulin resistance as a consequence of activation of the sympathetic nervous system. Risk for developing DM2 further increases in patients with OSAS and obesity. Data regarding effects of positive airway pressure (PAP) therapy, gold standard treatment for OSAS, on glycemic control were inconsistent due to variability in duration of and adherence to PAP therapy. In our cohort study we investigated effects of PAP treatment on glucose metabolism in normal-weighted non-diabetic OSAS patients, in obese non-diabetic OSAS patients, and in OSAS patients with DM2. We prospectively analyzed 67 patients diagnosed with OSAS and documented to be effectively treated with PAP therapy for three months. Apnea-hypopnea index was highest in the diabetic group, being significantly higher than in the normal-weighted group (p=0.021). Mean HOMA values were significantly higher in obese (p=0.002) and diabetic group (p=0.001) than normal-weighted group; the differences were still significant after PAP therapy. HbA1c levels were significantly higher in diabetic group compared to those in normal-weighted (p=0.012) and obese (p=0.001) groups. After PAP treatment, decrease in HbA1c levels were significant in normal-weighted (p=0.008), obese (p=0.034), and diabetic (p=0.011) groups. There was no correlation with the change in HbA1c levels and age (p=0.212), BMI (p=0.322), AHI (p=0.098) or oxygen levels (p=0.122). Our study showed that treatment of OSAS by PAP therapy offers beneficial effect on glucose metabolism, not only in diabetic patients, but also in obese and normal-weighted OSAS patients. Although data regarding overall effects of PAP therapy on glycemic control present contradictory results in the literature, it should be emphasized that duration and adherence to PAP therapy were main determinants for beneficial outcome of treatment.

The Effect of Change in Posture on Spirometry in Patients with Obstructive Sleep Apnoea Syndrome.

ObjectivesObstructive sleep apnoea syndrome (OSAS) is a growing health concern as it is associated with serious comorbidities. OSAS is mainly related to obesity, age, gender and a narrowed upper airway is commonly seen in patients with OSAS. This study aimed to compare spirometry parameters between obese OSAS patients and non-obese OSAS patients when patients moved from sitting to supine.MethodsThis cross-sectional study was conducted at Sultan Qaboos University Hospital, Muscat, Oman, between December 2009 and December 2010. Patients with severe OSAS and who were OSAS treatment naïve were recruited. Spirometry was performed in all patients in sitting and supine positions to assess forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, forced expiratory flow (FEF) 50%, FEF 25–75%, maximum forced inspiratory flow and expiratory reserve volume. The mean difference in spirometry parameters between patients in sitting and supine positions was calculated.ResultsA total of 27 OSAS patients (19 males and 8 females) were included in this study. There was a significant difference in FEV1/FVC in obese and non-obese patients when changing position (P = 0.03). In addition, there was a significant change between male and female patients’ FVC percentages (P <0.05). Male patients with OSAS had reduced FVC compared to females. There was no significant difference in the remaining spirometry parameters with patients’ change of position.ConclusionA supine position may cause lower airway obstruction in obese patients with OSAS. The reduced FVC in males possibly contributes to the high prevalence of OSAS in men compared to women.

Mandibular advancement reveals long-term suppression of breathing discomfort in patients with obstructive sleep apnea syndrome

Obstructive sleep apnoea syndrome (OSAS) patients do not report breathing discomfort in spite of abnormal upper airway mechanics. We studied respiratory sensations in OSAS patients without and with mandibular advancement device (MAD).Fifty-seven moderate to severe non obese OSAS patients were asked about breathing discomfort using visual analogue scales (VAS) in the sitting position (VAS-1), after lying down (VAS-2), then with MAD (VAS-3). Awake critical closing pressure (awake Pcrit) was measured in 15 patients without then with MAD.None of the patients reported breathing discomfort when sitting but 19 patients (33%) did when lying (VAS-2: -20% or less). A feeling of "easier breathing" with MAD was observed and was more marked in patients reporting breathing discomfort when supine (VAS-3: +66.0% [49.0; 89.0]) than in those not doing so (VAS-3: +28.5% [1.0; 56.5], p = 0.007). MAD-induced change in awake Pcrit was correlated to VAS-3.In conclusion, MAD revealed “latent dyspnea” related to the severity of upper airways mechanics abnormalities in OSAS patients.

Does the neutrophil-to-lymphocyte ratio have any importance between subjects with obstructive sleep apnea syndrome with obesity and without obesity?

An increase in the incidence of OSAS (obstructive sleep apnoea syndrome) has been seen due to the reported association between OSAS and obesity. Subjects are predisposed to cardiovascular disease due to systemic inflammation caused by the interactions between obesity and OSA. Inflammatory markers could be used to predict the degree of systemic inflammation, which could be a prognostic factor for future adverse events such as metabolic risks. One marker that has recently started being used as an indicator of systemic inflammation is neutrophil-to-lymphocyte ratio (NLR). The aim is to evaluate NLR, which is a easily measured parameter of systemic inflammation in OSAS subjects with and without obesity. 155 subjects were assigned to four different groups according to their body mass indices. Comparisons of white blood cell, neutrophil, lymphocyte, NLR values and anthropometric measurements were done for each group. The NLR and neutrophil counts of group 4 were statistically significant and higher than those of groups 1, 2 and 3. The lymphocyte counts of group 4 were the lowest amongst all groups, these values were lower than the lymphocyte counts of groups 1, 2 and 3 with statistically significant differences (p< 001). A positive correlation was found between the body mass index and lymphocyte count values of obese OSAS subjects (r= 0.027, p= 353). The NLR ratio was found to be increasing by obesity grade and reveals that the associated inflammatory response also increases. The NLR ratio might be used as an inflammatory marker in obese OSAS subjects.

Vitamin D status of male OSAS patients improved after long-term CPAP treatment mainly in obese subjects

ObjectiveThe aim of this study was to evaluate the effect of one-year useful continuous positive airway pressure (CPAP) treatment on serum vitamin D levels in middle-aged men affected by obstructive sleep apnea syndrome (OSAS). MethodsThis is a secondary investigation related to a previously published observational study about the effect of short-term CPAP therapy on serum vitamin D levels in severe OSAS (Apnea-Hypopnea Index – AHI- >30/h) patients. In the present study, we included patients participating to the previous investigation who repeated serum vitamin D assessment after one year of useful CPAP treatment, and compared to control a group of OSAS patients with scarce compliance to CPAP treatment. OSAS patients with beneficial use of CPAP treatment were distributed in obese (Body Mass Index – BMI ≥30) and non-obese (BMI < 30). Moreover, the mean change between baseline and one-year follow-up (Δ) of serum vitamin D levels was correlated with demographic, polygraphic and clinical data throughout a multiple regression analysis. ResultsWe documented the significant increase of serum vitamin D levels after one year of CPAP treatment in the OSAS group (n = 39, p < 0.001) and in both subgroups of obese (n = 23, p < 0.01) and non-obese (n = 16, p < 0.01) OSAS patients. Conversely, OSAS patients with a scarce compliance to CPAP therapy did not change serum vitamin D levels after one year (n = 10, p > 0.05). OSAS patients with beneficial CPAP treatment showed higher vitamin D serum levels after one year and a more frequent shift from insufficient to sufficient vitamin D status compared to OSAS patients not adequately using CPAP treatment. In particular, the obese OSAS patients subgroup shifted from insufficient (≤20 ng/mL) to sufficient (>20 ng/mL) vitamin D status after CPAP therapy more than the non-obese OSAS patients subgroup (p < 0.05). We observed higher Δ of vitamin D serum levels, Epworth Sleepiness Scale score, and AHI in obese compared to non-obese OSAS patients. Finally, BMI obtained at baseline positively correlated with Δ of vitamin D serum levels. DiscussionThis study documented that long-term CPAP treatment is a viable therapeutic choice for correcting both sleep apnea condition and vitamin D deficiency in middle-aged male OSAS patients. Significantly, this effect was more evident in obese subjects and possibly represents a valid therapeutic strategy to ensure sufficient vitamin D levels in these patients, which frequently show a deficient vitamin D status.

MR Image Analytics to Characterize the Upper Airway Structure in Obese Children with Obstructive Sleep Apnea Syndrome.

PurposeQuantitative image analysis in previous research in obstructive sleep apnea syndrome (OSAS) has focused on the upper airway or several objects in its immediate vicinity and measures of object size. In this paper, we take a more general approach of considering all major objects in the upper airway region and measures pertaining to their individual morphological properties, their tissue characteristics revealed by image intensities, and the 3D architecture of the object assembly. We propose a novel methodology to select a small set of salient features from this large collection of measures and demonstrate the ability of these features to discriminate with very high prediction accuracy between obese OSAS and obese non-OSAS groups.Materials and MethodsThirty children were involved in this study with 15 in the obese OSAS group with an apnea-hypopnea index (AHI) = 14.4 ± 10.7) and 15 in the obese non-OSAS group with an AHI = 1.0 ± 1.0 (p<0.001). Subjects were between 8–17 years and underwent T1- and T2-weighted magnetic resonance imaging (MRI) of the upper airway during wakefulness. Fourteen objects in the vicinity of the upper airways were segmented in these images and a total of 159 measurements were derived from each subject image which included object size, surface area, volume, sphericity, standardized T2-weighted image intensity value, and inter-object distances. A small set of discriminating features was identified from this set in several steps. First, a subset of measures that have a low level of correlation among the measures was determined. A heat map visualization technique that allows grouping of parameters based on correlations among them was used for this purpose. Then, through T-tests, another subset of measures which are capable of separating the two groups was identified. The intersection of these subsets yielded the final feature set. The accuracy of these features to perform classification of unseen images into the two patient groups was tested by using logistic regression and multi-fold cross validation.ResultsA set of 16 features identified with low inter-feature correlation (< 0.36) yielded a high classification accuracy of 96% with sensitivity and specificity of 97.8% and 94.4%, respectively. In addition to the previously observed increase in linear size, surface area, and volume of adenoid, tonsils, and fat pad in OSAS, the following new markers have been found. Standardized T2-weighted image intensities differed between the two groups for the entire neck body region, pharynx, and nasopharynx, possibly indicating changes in object tissue characteristics. Fat pad and oropharynx become less round or more complex in shape in OSAS. Fat pad and tongue move closer in OSAS, and so also oropharynx and tonsils and fat pad and tonsils. In contrast, fat pad and oropharynx move farther apart from the skin object.ConclusionsThe study has found several new anatomic bio-markers of OSAS. Changes in standardized T2-weighted image intensities in objects may imply that intrinsic tissue composition undergoes changes in OSAS. The results on inter-object distances imply that treatment methods should respect the relationships that exist among objects and not just their size. The proposed method of analysis may lead to an improved understanding of the mechanisms underlying OSAS.

High Adherence to CPAP Treatment Does Not Prevent the Continuation of Weight Gain among Severely Obese OSAS Patients.

Obstructive sleep apnea syndrome (OSAS) patients benefit from continuous positive airway pressure (CPAP) treatment in a dose-response manner. We determined adherence and weight control, as well as their predictors, among long-term CPAP users. Cohort of 1,023 OSAS patients had used CPAP on average of 6.6 ± 1.2 years. BMI was determined at baseline and at follow-up visits. There were 7.4 ± 1.7 BMI and 6.5 ± 1.8 CPAP usage measurements per patient on average. Using the Bayesian hierarchical model, we determined the patients' individual trends of BMI and adherence development. Patients with significantly increasing or decreasing trends were identified at the posterior probability level of > 90%. The mean age in the cohort was 55.6 ± 9.8 years, BMI 33.5 ± 6.4 kg/m(2), apnea-hypopnea index 33.7 ± 23.1, and CPAP usage 6.0 ± 1.8 h/day. The majority of patients had no significant change in BMI (mean annual weight gain 0.04 ± 0.29 kg/m(2)) or CPAP adherence (mean annual increase 11.4 ± 7.0 min/day). However, at the individual level, 10% of the patients showed significant annual weight gain (0.63 ± 0.35 kg/m(2)) during the 5-year follow-up period. At baseline these patients were already more severely obese (mean BMI 40.0 ± 5.9 kg/m(2)) despite being younger (mean 50.9 ± 9.5 years) than the rest of the cohort. In the majority of CPAP-treated OSAS patients, weight did not significantly change but gained slightly slower than in age-matched population in general. However, in 10% of patients, high adherence to CPAP treatment did not prevent the continuation of weight gain. These patients present a high-risk group for OSAS-related multimorbidity later in life.

Is There a Relationship between Obstructive Sleep Apnea Syndrome Severity and Nesfatin-1?

Background: Obstructive sleep apnea syndrome (OSAS) and obesity frequently occur together. The relationship between increased appetite and obesity is well known; however, despite existing knowledge about the relationship between OSAS and obesity, it is not fully understood. Objectives: This study aimed to evaluate the relationship between OSAS and the appetite-suppressing hormone nesfatin-1 independent of body mass index (BMI). Methods: A total of 134 cases were included in the study; 102 with OSAS (OSAS group) and 32 healthy controls (control group). All cases underwent polysomnography, and nesfatin-1 levels were determined. Results: Nesfatin-1 levels were significantly lower in the OSAS group compared to the control group (3,776.5 ± 204.8 and 4,056.2 ± 101.5 pg/ml, respectively; p < 0.001). In addition, there was a statistically significant negative correlation between nesfatin-1 and the apnea hypopnea index (r = -0.543; p < 0.001). The statistically significant relationship persisted after adjusting for confounding intergroup factors such as age, gender and BMI (p < 0.001). In the OSAS group, there was a statistically significant correlation between nesfatin-1 and neck circumference (r = -0.304; p = 0.02) but not between nesfatin-1 and BMI and waist circumference. There was no statistically significant difference in nesfatin-1 levels between the sexes. Conclusion: OSAS patients have lower nesfatin-1 levels compared to controls, and a greater nesfatin-1 deficit corresponds to an increased severity of OSAS and an increased neck circumference. Replacement therapy may be a potential treatment for obese OSAS patients who have lower nesfatin-1 levels, which may have additional benefits through appetite suppression and weight loss.

Prevalence, clinical significance, and predictors for sleep-related hypoventilation among obese Asians with obstructive sleep apnea syndrome

Introduction Sleep-related hypoventilation may be important in the development of hypercapnic respiratory failure in obstructive sleep apnea syndrome (OSAS) particularly in obese group. Current available data on clinical significance of sleep-related hypoventilation is still lacking. Objective: To study the prevalence, clinical significance, and predictors of sleep-related hypoventilation among obese OSAS patients. Materials and methods Retrospective analysis of 221 patients diagnosed with OSAS. Sleep-related hypoventilation was defined as definite or possible using criteria as follows; an increase of >10 mmHg of end tidal CO2 during sleep in comparison to an awake supine value or low baseline asleep oxygen saturation ⩽85% not explained by apnea or hypopnea; respectively. No hypoventilation was defined if the patients did not meet above two criteria. We conducted two arms of analysis; study arm I compared the group with definite and possible hypoventilation against no hypoventilation group and study arm II compared the group with definite hypoventilation against possible hypoventilation and no hypoventilation groups. Results 35.75% and 31.22% exhibited sleep-related hypoventilation in study arm I and II, respectively. Sleep-related hypoventilation group in both study arms had more cardiovascular comorbidities and more severe sleep disordered breathing. Logistic regression analysis showed that BMI, total AHI, ESS, and morning headache (at least 3–4 times a week) were independent predictors of sleep-related hypoventilation in both study arms. Using regression co-efficient analysis, prediction scores using the above variables were derived to predict the likelihood of sleep-related hypoventilation at different sensitivity and specificity rates. Conclusion We established important clinical significance and predictors of sleep-related hypoventilation which can be utilized to predict the probability of having sleep-related hypoventilation with reasonable sensitivity and specificity. Acknowledgements We would like to thank Mr. Dittapol Muntham, a statistician. at the Section of Clinical Epidemiology and Biostatistics, Faculty of Medicine, Ramathibodi Hospital for additional statistical review.

Comparison of clinical characteristics in patients with obesity hypoventilation syndrome and obese obstructive sleep apnea syndrome: a case‐control study

Obesity hypoventilation syndrome (OHS) can be overlooked unless clinicians have a high index of suspicion. The present case-control study aimed to compare characteristics of patients with OHS and obese obstructive sleep apnea syndrome (OSAS), and to identify determinants of hypercapnia in OSAS patients. Demographic and anthropometric features, pulmonary function tests, blood gas analysis and sleep parameters of 59 OHS patients were compared to 295 body mass index-matched OSAS patients. The rate of hypertension (67.8% vs 53.2%, respectively, P=0.027) was higher in OHS than OSAS group. In OHS patients, FVC (%) (P<0.0001), FEV1 (%) (P=0.001) and PaO2 (P<0.0001) were lower, whereas PaCO2 and HCO3 levels were increased (P<0.0001). Daytime sleepiness was more frequent (89.8% vs 68.5%, respectively, P=0.002), and Epworth sleepiness scores were higher (14.0 vs 11.9, respectively, P=0.021) in OHS than OSAS patients. In polysomnography, lowest and mean SpO2 were decreased, and sleep time with SpO2 <90% was increased in patients with OHS (P<0.0001). Multivariate analysis showed that hypercapnia was associated independently with HCO3 (P<0.0001) and daytime SaO2 (P=0.003). Besides, HCO3 level ≥ 27 mEq/L had a sensitivity of 88.1% and specificity of 73.1%, and SaO2 ≤ 95% had a sensitivity of 64.4% and specificity of 73.9% for identifying OHS. It was shown that OHS patients have increased rate of hypertension, daytime sleepiness and HCO3 , and decreased lung functions and PaO2 levels than OSAS patients. The present results support that elevated bicarbonate levels and decreased oxygen saturations in obese OSAS patients should prompt clinicians to predict OHS.

Ventilatory Responses to Hypercapnia during Wakefulness and Sleep in Obese Adolescents With and Without Obstructive Sleep Apnea Syndrome

Abnormal ventilatory drive may contribute to the pathophysiology of the childhood obstructive sleep apnea syndrome (OSAS). Concomitant with the obesity epidemic, more adolescents are developing OSAS. However, few studies have specifically evaluated the obese adolescent group. The authors hypothesized that obese adolescents with OSAS would have a blunted hypercapnic ventilatory response (HCVR) while awake and blunted ventilatory responses to carbon dioxide (CO(2)) during sleep compared with obese and lean adolescents without OSAS. CVR was measured during wakefulness. During nonrapid eye movement (NREM) and rapid eye movement (REM) sleep, respiratory parameters and genioglossal electromyogram were measured during CO(2) administration in comparison with room air in obese adolescents with OSAS, obese control study participants, and lean control study participants. Sleep laboratory. Twenty-eight obese patients with OSAS, 21 obese control study participants, and 37 lean control study participants. The obese OSAS and obese control groups had a higher HCVR compared with the lean control group during wakefulness. During both sleep states, all 3 groups had a response to CO(2); however, the obese OSAS group had lower percentage changes in minute ventilation, inspiratory flow, inspiratory time, and tidal volume compared with the 2 control groups. There were no significance differences in genioglossal activity between groups. HCVR during wakefulness is increased in obese adolescents. Obese adolescents with OSAS have blunted ventilatory responses to CO(2) during sleep and do not have a compensatory prolongation of inspiratory time, despite having normal CO(2) responsivity during wakefulness. Central drive may play a greater role than upper airway neuromotor tone in adapting to hypercapnia.

Effect of Mediterranean dietversusprudent diet combined with physical activity on OSAS: a randomised trial

We aimed to evaluate the effect of the Mediterranean diet (MD) compared with a prudent diet (PD) combined with physical activity on obese obstructive sleep apnoea syndrome (OSAS) patients who were treated with continuous positive airway pressure. 900 patients were evaluated and 40 obese patients (body mass index ≥ 30.0 kg · m(-2)) who met the inclusion criteria, with moderate-to-severe OSAS (apnoea-hypopnoea index (AHI) >15 events · h(-1) and Epworth Sleepiness Scale score >10) based on overnight attended polysomnography, were included in the study. After randomisation, 20 patients followed the MD and 20 a PD for a 6-month period. All patients were counselled to increase their physical activity. Concerning sleep parameters, only AHI during rapid eye movement (REM) sleep was reduced to a statistically significant degree, by mean ± SD 18.4 ± 17.6 events · h(-1) in the MD group and by 2.6 ± 23.7 events · h(-1) in the PD group (p<0.05). The MD group also showed a greater reduction in waist circumference (WC) (-8.7 ± 3.6 cm), WC/height ratio (-0.04 ± 0.02 cm · m(-1)) and WC/hip ratio (-0.04 ± 0.03 cm · cm(-1)), compared with the other group (-2.6 ± 1.7 events · h(-1), -5.7 ± 3.8 cm, -0.03 ± 0.02 cm · m(-1) and 0.02 ± 0.02 cm · cm(-1), respectively; p<0.05). Our results showed that the MD combined with physical activity for a 6-month period was effective in reducing the AHI during REM sleep without any statistically significant effect in the other sleep parameters, compared with a PD in obese adults with moderate-to-severe OSAS.

Obstruktive Schlafapnoe bei Normal- und Übergewichtigen im Vergleich

Obesity is a well established risk factor for developing an obstructive sleep apnea syndrome (OSAS). However, normal weighted patients can suffer from OSAS, too. This study compares breathing disorders and their effect on sleep of normal weighted and obese OSAS patients. The main sleep parameters of 32 normal weighted OSAS patients (body mass index, BMI ≤ 25 kg/m2) were compared with those of 32 obese OSAS patients (BMI ≥ 35 kg/m2) with a virtually equal apnea-hypopnea index (AHI ± 3). The mean AHI in both groups was 27.9/h (BMI ≤ 25 kg/m2) and 28.0/h (BMI ≥ 25 kg/m2), respectively. Sleep efficiency, relative percentages of sleep phases S1-S4 and REM, mean, minimal and maximal heart rate were not significantly different in statistic analysis in normal weighted and obese patients. Normal weighted OSAS patients had a higher apnea index (11.4 vs. 6.4, p=0.040), a higher minimal (81.3% vs. 71.7, p=0.003) and mean (94.9% vs. 92.8%, p=0.007) oxygen saturation, but a smaller hypopnea index (16.5 vs. 21.6, p=0.047) and a lower index of snoring (175.2 vs. 394.1, p<0.001) than their obese counterparts. In OSAS patients with an equal AHI, the obese have fewer apneas, but more hypopneas, and a lower minimal oxygen saturation than normal weighted patients. The effect of OSAS on the sleep architecture, however, seems not to be associated with the patients' body weight.

Metabolic syndrome, insulin resistance, fibrinogen, homocysteine, leptin, and C-reactive protein in obese patients with obstructive sleep apnea syndrome.

OBJECTIVE:The prevalence of obstructive sleep apnea syndrome (OSAS) and metabolic syndrome is increasing worldwide, in part linked to epidemic of obesity. The purposes of this study were to establish the rate of metabolic syndrome and to compare fibrinogen, homocysteine, high-sensitivity C-reactive protein (hsCRP), leptin levels, and homeostasis model assessment insulin resistance (HOMA-IR) in the obese patients with and without OSAS.METHODS:The study population included 36 consecutive obese patients with OSAS (23 males; mean age, 50.0 ±19.7 years), and 34 obese patients without OSAS (17 males; mean age, 49.7±11.1 years) were enrolled as control group. Metabolic syndrome was investigated; fibrinogen, homocysteine, CRP, and leptin levels were measured, and IR was assessed.RESULTS:Metabolic syndrome was found in 17 (47.2%) obese OSAS patients, whereas only 29.4% of obese subjects had metabolic syndrome (P > 0.05). Obese patients with OSAS had significantly higher mean levels of triglyceride (P < 0.001), total-cholesterol (P = 0.003), low-density lipoprotein-cholesterol (P = 0.001), fasting glucose (P = 0.01), HOMA-IR (P <0.001), thyroid-stimulating hormone (P = 0.03), fibrinogen (P < 0.003), hsCRP (P <0.001), and leptin (P = 0.03) than control group . Besides, leptin level was positively correlated with waist (r = 0.512, P = 0.03) and neck circumferences (r = 0.547, P = 0.03), and fasting glucose (r = 0.471, P = 0.04) in OSAS patients, but not in obese subjects.CONCLUSION:This study demonstrated that obese OSAS patients may have an increased rate of metabolic syndrome and higher levels of serum lipids, fasting glucose, IR, leptin, fibrinogen, and hsCRP than obese subjects without sleep apnea. Thus, clinicians should be encouraged to systematically evaluate the presence of metabolic abnormalities in OSAS and vice versa.

A Two-Year Weight Reduction Program in Obese Sleep Apnea Patients

To evaluate the effects of a 2-year weight reduction program on respiratory disturbances, arousal index, daytime sleepiness, metabolic status, and quality of life in obese patients with obstructive sleep apnea syndrome (OSAS). Prospective intervention study of 33 consecutive obese OSAS patients (24 men, 9 women); 19 subjects used continuous positive airway pressure and 4 used mandibular retaining device, except during nights with sleep recording. The program consisted of 8 weeks of low calorie diet followed by group meetings with behavioral change support. Seventy percent of the patients completed the program; 67% completed the sleep recordings. The success rate for the apnea-hypopnea index (AHI) (< 20 and reduction > or = 50%) was 15% in the intention to treat (ITT) analysis. The AHI showed a nonsignificant decrease in mean values, from 43 to 28. The oxygen desaturation index (ODI) decreased from 42 to 23 (p = 0.010), arousal index from 24 to 11 (p = 0.019), body mass index from 40 to 35 (p = 0.003) and the Epworth Sleepiness Scale (ESS) from 9 to 5 (p = 0.026), all ITT. Metabolic status, physical functioning, and vitality evaluations improved only in the per protocol analysis. Reduction in weight correlated significantly to reductions in ESS (p = 0.038) and insulin levels (p = 0.002), respectively. There were no differences based on gender or use/non-use of OSAS treatment device. Our weight reduction program showed a limited success in reducing AHI. However, there were significant improvements in weight, ODI, arousal index, and subjective symptoms. We recommend the program as an adjunct treatment for well-motivated obese OSAS patients.

Inflammatory Markers in Middle-Aged Obese Subjects: Does Obstructive Sleep Apnea Syndrome Play a Role?

Background. Obstructive Sleep Apnea Syndrome (OSAS) is associated with inflammation, but obesity may be a confounding factor. Thus, the aim of this study was to explore differences in serum levels of inflammation markers between obese individuals with or without OSAS. Methods. Healthy individuals (n = 61) from an outpatient obesity clinic were examined by polysomnography and blood analysis, for measurement of TNF-α, IL-6, CRP, and fibrinogen levels. According to Apnea-Hypopnea Index (AHI), participants were divided into two BMI-matched groups: controls (AHI < 15/h, n = 23) and OSAS patients (AHI ≥ 15/h, n = 38). Results. OSAS patients had significantly higher TNF-α levels (P < .001) while no other difference in the examined inflammation markers was recorded between groups. Overall, TNF-α levels were correlated with neck circumference (P < .001), AHI (P = .002), and Oxygen Desaturation Index (P = .002). Conclusions. Obese OSAS patients have elevated TNF-α levels compared to BMI-matched controls, suggesting a role of OSAS in promoting inflammation, possibly mediated by TNF-a.