Severe Obstructive Sleep Apnea Group Research Articles

Vibration signals of snoring as a simple severity predictor for obstructive sleep apnea.

Polysomnography (PSG), which involves simultaneous monitoring of various physiological monitors, is the current comprehensive tool for diagnosing obstructive sleep apnea (OSA). We aimed at validating vibrating signals of snoring as a single physiological parameter for screening and evaluating severity of OSA. Totally, 111 subjects from the sleep center of a tertiary referral center were categorized into four groups according to the apnea hypopnea index (AHI) obtained from PSG: simple snoring group (5 > AHI, healthy subjects, n = 11), mild OSA group (5 ≤ AHI < 15, n = 11), moderate OSA group (15 ≤ AHI < 30, n = 30) and severe OSA group (AHI ≥ 30, n = 59). Anthropometric parameters and sleep efficiency of all subjects were compared. Frequencies of amplitude changes of vibrating signals on anterior neck during sleep were analyzed to acquire a snoring burst index (SBI) using a novel algorithm. Data were compared with AHI and index of arterial oxygen saturation (Δ Index). There were no significant differences in age and sleep efficiency among all groups. Bland-Altman analysis showed better agreement between SBI and AHI (r = 0.906, P < 0.001) than Δ Index and AHI (r = 0.859, P < 0.001). Additionally, receiver operating characteristic (ROC) showed substantially stronger sensitivity and specificity of SBI in distinguishing between patients with moderate and severe OSA compared with Δ Index (sensitivity: 81.4% vs 66.4%; specificity: 96.7% vs 86.7%, for SBI and Δ Index, respectively). SBI may serve as a portable tool for screening patients and assessing OSA severity in a non-hospital setting.

Evaluation of a 2-channel portable device and a predictive model to screen for obstructive sleep apnea in a laboratory environment.

Various portable monitors for identifying obstructive sleep apnea (OSA) have been investigated and reported to enable accurate recording of OSA severity. However, more information is needed from different populations. This study was conducted to evaluate the efficiency of a portable 2-channel sleep apnea device (SleepView) for screening OSA in the Chinese population. Ninety-three consecutive subjects underwent simultaneous SleepView testing and laboratory polysomnography (PSG) monitoring. Data were collected and blindly analyzed. The efficiency of the SleepView device and a newly established predictive model for identifying OSA was evaluated in comparison with PSG. Good agreement was evident between the SleepView and PSG based on the apnea-hypopnea index (AHI; r(2) = 0.84, P < .01). The median AHI yielded by the SleepView was higher than that of PSG: 33.2 (interquartile range of 10.5-53.3) versus 19.2 (interquartile range of 5.2-53.6). The sensitivity and specificity of the SleepView for a PSG AHI of ≥ 5 were 80.28% and 95.45%, respectively, and the cutoff was 16.8. The area under the receiver operating curve for PSG AHIs of ≥ 5, > 15, and > 30 was 0.923, 0.924, and 0.979, respectively. When the AHI and oxygen desaturation index calculated by the SleepView were combined with waist circumference, the new predictive model showed a higher sensitivity of 92.96% and a specificity of 95.45% for a PSG AHI of ≥ 5, and the corresponding area under the receiver operating curve was 0.983. The SleepView device exhibited acceptable diagnostic accuracy for OSA in the Chinese population, especially in the severe OSA group. A practical predictive model comprising waist circumference, AHI, and oxygen desaturation index obtained with the SleepView was highly effective for screening even mild OSA. This simple and practical device may serve as a useful tool to screen for OSA. Further studies are required to validate the diagnostic efficiency of the SleepView in the home environment and in different populations.

Association of inflammation and oxidative stress with obstructive sleep apnea in ischemic stroke patients

ObjectiveThe role of obstructive sleep apnea (OSA) in the mortality and further cardiovascular risk in subjects with ischemic stroke remains a contentious issue. Oxidative stress and inflammatory reaction due to OSA have seldom been studied in stable ischemic stroke patients. Patients/MethodsThis cross-sectional, prospective study involved 92 consecutive ischemic stroke patients who were admitted to the Rehabilitation ward. All subjects received polysomnography and laboratory tests for oxidative stress and inflammatory biomarkers, including: C-reactive protein (CRP), interleukin 6 (IL-6), total antioxidant capacity (TAC), and urinary 8-hydroxy-2-deoxyguanosine. Differences in study variables between patients with or without severe OSA were compared, and multivariate linear regression analyses were used to assess the relationship between OSA severity and target biomarkers. ResultsParticipants in the severe OSA group were significantly older (p = 0.002), had a significantly higher risk of hypertension (p = 0.021) and a lower level of CRP (p = 0.006). Among the subjects with ischemic stroke and severe OSA, the levels of CRP, IL-6, and TAC were positively correlated with the desaturation index (DI) and the TAC levels were negatively correlated with mean arterial oxygen saturation (SaO2). Regression analysis results indicated that the TAC levels remained significantly and negatively correlated with mean SaO2 levels. Moreover, the CRP levels remained significantly correlated with the apnea–hypopnea index and DI after controlling for covariates. ConclusionsThe present study demonstrated that a preferentially adaptive antioxidative response to hypoxia emerges, and the role of OSA with respect to inflammatory reaction is attenuated, in ischemic stroke patients with OSA.

An Invitation for Rethinking about Echocardiographic Abnormalities in Patients with Sleep Apnea Syndrome

We read with great interest the article entitled Echocardiographic abnormalities in patients with sleep apnea syndrome, published online in Archives of Cardiovascular Imaging on January 12th, 2014 (1). The authors sought to determine the cardiovascular disorder at an early stage in patients with sleep apnea syndrome (OSA) with different echocardiographic parameters. They found both relative left ventricular systolic and diastolic dysfunction and dysfunction at some echocardiographic parameters of the right ventricle. We have some comments about this study. Firstly, there is a major concern about the methodology of the study. The study group consists of male subjects whose disease duration is not known. To our knowledge, the disease is frequently seen in woman patients too (2). Furthermore, the disease duration is not known for the subjects. Thus, comparison of the results is not appropriate: for example, suppose that there is a patient with mild OSA of 10 years' duration and there is also another patient with severe OSA of 3-4 years' duration. The authors have mentioned this point in the limitations section, but it should be written in the patients and methods section. Secondly, the fact that the study is not the first study in the literature on the subject was not mentioned in the references. Aslan et al. published their work in Cardiology Journal in 2013 (3). They studied 80 patients with the OSA syndrome while excluding those with hypertension, diabetes, or any known cardiac disease, which makes their study more reliable. They divided the patients into two groups of normal/mild OSA group and moderate/ severe OSA group. Their study, however, was not as comprehensive as the original study. Tissue Doppler echocardiography showed that early diastolic myocardial velocity was lower in the second group (21 ± 5.6/s in group 1 vs. 18.3 ± 5.3 cm/s in group 2; P = 0.01). They concluded that left ventricular (LV) diastolic dysfunction, hypertrophy, and left atrial dilatation occurred in the OSA patients even before the development of hypertension and other cardiovascular disease. In the original study, strain imaging was used and changes at the basal septum strain rate (P =0.005) were associated with OSA severity. We should note that strain imaging is a new and more reliable method in terms of diastolic function. Thirdly, Cicek et al. prospectively studied 64 patients in terms of echocardiographic and aortic parameters (4). Their study was not as comprehensive as the present one with respect to echocardiographic examinations. They found that the LV systolic function did not differ between groups, which was a different result from the present study. They also concluded that the LV diastolic function and aortic elastic parameters deteriorate with the severity of OSA. The different result in terms of the LV systolic function might be due to the small number of subjects in both studies. In conclusion, we thank our colleagues for their effort to encourage us to think about this disease. We believe that the methodology of the study is inappropriate for drawing a conclusion in terms of the LV and right ventricular function and future research is needed to make a strong conclusion. We may obtain better information on the cardiovascular function in OSA patients with another study. Indeed, future research should recruit female subjects and subjects with known disease duration and exclude individuals with hypertension, diabetes, and other cardiovascular diseases.

Factors influencing sleep time with oxygen saturation below 90% in sleep-disordered breathing.

To determine factors influencing sleep time with oxygen saturation below 90% (ST₉₀) in a population referred to a tertiary sleep center for assessment of possible sleep-disordered breathing (SDB). Retrospective review of demographic and polysomnographic data of 731 consecutive patients with suspected SDB. Bivariate correlation analyses were performed, and Spearman rho coefficients were calculated. Variables with a marginal association with ST₉₀ (P < .05) in the bivariate analysis were included into the multiple regression analysis. The distributions of SDB were as follows: normal/simple snoring, 18.2%; mild obstructive sleep apnea (OSA), 25.6%; moderate OSA, 17.4%; and severe OSA, 38.9%. The univariate analysis revealed a significant correlation between ST₉₀ and age (r = 0.204), body mass index (BMI) (r = 0.440), arousal index (r = 0.754), apnea-hypopnea index (AHI) (r = 0.761), mean oxygen saturation (SaO₂) (r = -0.506), and mean O₂ desaturation (r = 0.858) (P < .001 for all parameters). In multiple regression analysis, age (P < .001), BMI (P = .040), male gender (P = .001), AHI (P < .001), mean SaO₂ (P < .001), and mean O₂ desaturation (P < .001) were found to be independent parameters influencing ST₉₀. Furthermore, these parameters explained a significant proportion of variance in ST₉₀ (R(2) = 0.794, F (6, 729) = 464.65, P < .001). Although there was a strong correlation between AHI and ST₉₀ (r = 0.76, P < .001), a large variation of ST₉₀ values was observed, especially within the severe OSA group. The study results provide supporting evidence that patients with similar AHI may have quite different values of ST₉₀, and thereby hypoxia. The stratification of patients with OSA according to AHI combined with ST₉₀ may allow better identification of prognostic information.

Targeted Multilevel Surgical Management of Obstructive Sleep Apnea: A Case Series of 44 Patients

Objectives: (1) Assess the effectiveness of multilevel surgery in the treatment of obstructive sleep apnea (OSA). (2) Analyze outcomes based on reduction of apnea hypopnea index (AHI) and positive airway treatment pressures. Methods: Case-series review in a tertiary referral center. A total of 44 patients underwent multilevel OSA surgery between November 2009 and September 2013. Depending on the preoperative examination and OSA severity based on sleep study, patients underwent multilevel surgery including nasal, oropharyngeal, transoral robotic, tongue base, hyoid, and/or orthognathic surgery. Follow-up sleep studies at 4 months were obtained and compared with preoperative data. Results: Overall AHI was significantly reduced from a mean of 44.5 to 19.9 ( P = .0008), 78.9 to 35.8 ( P = .0001) in the severe OSA group, 21.4 to 7.0 ( P = .0001) in the moderate group, and 8.7 to 4.5 ( P = .0004) in the mild group. AHI reduced from mean of 98.1 to 31.7 ( P = .0013) in those who underwent orthognathic surgery and 36.1 to 18.1 ( P = .011) in those who had soft tissue procedures without orthognathic surgery. Overall continuous positive airway pressure (CPAP) improved from mean of 10.9 to 4.7 cmH20 ( P = .0001). Body mass index was significantly higher in the severe OSA group than the mild and moderate groups. No significant difference was noted in neck circumference between the 3 groups. Conclusions: Targeted multilevel OSA surgery in this cohort was successful in an overall reduction of AHI and CPAP pressures. The maximum improvement in AHI was seen in patients with moderate OSA and in those who had an orthognathic procedure.

Early Detection of Brain White Matter Damage in Patients with Severe OSA

Objectives: Obstructive sleep apnea (OSA) is commonly associated with neuropsychological sequelae, presumably induced by brain injury resulting from intermittent hypoxia. Newer magnetic resonance imaging modalities allow a more accurate examination of fiber integrity of the brain microstructure. Diffusion tensor imaging (DTI) is sensitive to the microstructure of brain tissue. This study is to evaluate the integrity of white matter in OSA patients with DTI. Methods: The subjects underwent a polysomnography study to determine the severity of OSA and DTI scans to detect fiber integrity. Fractional anisotropy (FA), a measure of fiber integrity, was derived from the diffusion tensor, resulting in a whole brain FA map. The FA maps were compared using voxel-based statistics to determine differences between severe OSA and control groups, with age and sex as a covariate. The correlation between FA value and clinical severity was performed. Results: Twenty patients with severe OSA (apnea/hypopnea index, AHI &gt;30/h) and 14 sex- and age-matched healthy volunteers (AHI &lt;5/h) were recruited. The exploratory group-wise comparison showed that severe OSA patients exhibited reduced FA values in several brain clusters, including the white matter underlying amygdala, superior temporal gyrus, inferior parietal lobule, precuneus, postcentral gyrus, anterior cingulate gyrus, claustrum, insula, basal ganglia, tapetum, and cerebral peduncle compared with controls. The FA values were negatively correlated with clinical disease severity. Conclusions: This study indicates that OSA patients have impaired white matter integrity in vulnerable regions, associated with increased disease severity. The findings likely represent the pathological process of the brain in OSA patients.

Prevalence of glaucoma in patients with moderate to severe obstructive sleep apnea: ocular morbidity and outcomes in a 3 year follow-up study.

This study was conducted to investigate the prevalence and progression of glaucoma in patients receiving treatment for obstructive sleep apnea (OSA). We also investigated whether there is an association between severity of OSA and the incidence of glaucoma. A total of 39 patients aged >30 years who had been diagnosed with moderate and severe OSA in the sleep clinic at Hamad General Hospital were assessed for the presence of glaucoma. The severity of OSA was graded as mild, moderate, or severe based on American Association of Sleep Medicine (AASM) criteria using the apnea hypopnea index. Before enrollment, all patients underwent a complete ophthalmic examination including serial visual field tests, optical coherence tomography (OCT) with fundus photographs, and pachymetry. Enrolled patients were followed up in the ophthalmology outpatient clinic and sleep clinic for a period of 3 years. Examinations found that 8 (20.5%; 95% confidence interval (CI) 9.9-37%) of the 39 patients with OSA had glaucoma. Six (75%; 95% CI 36-96%) of these patients had normal-tension glaucoma (NTG) and two (25%; 95% CI 4.5-64.4%) patients had high-tension glaucoma. Among the 27 patients with severe OSA, 7 (25.9%; 95% CI 8-34%) had glaucoma, and among 12 patients with moderate OSA, 1 (8.3%; 95% CI 0.1-15%) had glaucoma. During the course of follow-up, two patients who previously did not have glaucoma were reclassified as NTG and two patients with glaucoma deteriorated. A higher prevalence of glaucoma in the severe OSA group compared with the moderate OSA group was found, albeit a statistically significant difference could not be attained (P=0.4). Our study showed that severe OSA is an important risk factor for developing glaucoma. Adequate treatment of OSA, along with optimal ophthalmic care, resulted in better control of glaucoma.

Breathing sounds spectral and higher order statistics changes from wakefulness to sleep in apneic and non-apneic people.

Breathing sounds analysis conveys valuable information in relation to obstructive sleep apnea (OSA) during both sleep and wakefulness. In this study, we investigated whether the breathings sounds spectral and higher order statistics characteristics (HOS) change from wakefulness to sleep, and more importantly whether this change is associated with severity of OSA. Tracheal breathing sounds of 6 individuals with severe OSA and 6 non-OSA individuals during wakefulness and stage 2 of sleep, both in supine position, were used in this study. The sounds were recorded simultaneously with full overnight polysomnography (PSG) assessment. First, the sounds of 5 noise-free breathing cycles were extracted and sequestered into inspiratory and expiratory phase segments manually for each study subject. After normalizing each sound segment to its energy, spectral and HOS features were calculated. Several features including the median bispectral frequency (MBF), spectral bandwidth (BW) and bispectrum Harmonic Mean (HM) were found to change statistically significantly from wakefulness to sleep mostly in severe OSA group but not as much in non-OSA group. The most prominent and consistent change between the two groups of OSA and non-OSA was observed in MBF; it changed from wakefulness to sleep in the two groups in an opposite manner; this observation is congruent with the hypothesis that the upper airway in OSA population has an increased non-homogeneity.

Uric Acid as a Potential Mediator of Cardiovascular Morbidity in Obstructive Sleep Apnea Syndrome

Abstract Background and aims Obstructive sleep apnea (OSA) is now considered as an independent risk factor for cardiovascular (CV) disease. Although uric acid is increasingly being implicated in CV morbidity and mortality, no study attempted to determine independent role of uric acid in CV morbidity of OSA patients. We aimed to assess the role of serum uric acid as a potential mechanism of CV morbidity in a nonselected cohort of OSA patients. Methods This was a cohort study in which patients who had undergone a formal sleep study for diagnosis of OSA were recruited. Included patients were grouped according to apnea–hypopnea index (AHI) as mild, moderate and severe OSA. Patients with AHI Results 436 OSA patients included (72 controls, 97 with mild, 75 with moderate, and 192 with severe OSA). The severe group also had higher serum uric acid level compared with the control and other OSA groups. Linear regression showed that the Ln uric acid was positively associated with Ln AHI score. In unadjusted logistic regression, severe OSA was associated with higher odds of a cardiovascular event, OR = 2.81 (1.307–6.041), p = 0.0081 while the other categories of sleep apnea were not. However, severe OSA was no longer significant after adjusting for age, gender, diabetes mellitus status, hypertension status, BMI, and smoking, OR = 1.882 (0.826–4.287), p = 0.1322. Uric acid was significantly higher in those who had a cardiovascular event even in the mild, moderate and severe OSA groups. Conclusion Hyperuricemia is strongly associated with cardiovascular disease in OSA patients. This strong relationship persists even after controlling for well-known traditional risk factors for cardiovascular disease.

Severity of obstructive sleep apnea is associated with elevated plasma fibrinogen in otherwise healthy patients

Obstructive sleep apnea (OSA) has been implicated in both cardiovascular and cerebrovascular diseases. Systemic inflammation and coagulation may be related to cardiovascular pathophysiology in patients with OSA. Fibrinogen is a major coagulation protein associated with inflammation, and long-term elevated plasma fibrinogen is associated with an increased risk of major cardiovascular diseases. We assessed whether severity of OSA is associated with levels of fibrinogen in newly diagnosed, untreated, and otherwise healthy OSA patients. We studied 36 men with OSA and 18 male control subjects (apnea-hypopnea index [AHI]<5 events/h). OSA patients were divided into mild (AHI≥5<15 events/h) and severe (AHI≥15 events/h) OSA groups. Morning fibrinogen levels in OSA patients were compared to those in control subjects of similar age, body mass index, blood pressure, smoking habits, and alcohol consumption. Fibrinogen levels were significantly elevated in patients with severe OSA compared to both control (P=0.003) and mild OSA (P=0.02) subjects after adjustment for covariates. However, there were no significant differences in fibrinogen levels between mild OSA and control subjects. Fibrinogen levels were directly related to AHI and arousal index and inversely related to mean and lowest oxygen saturation during sleep. Severity of OSA was associated with increased fibrinogen level independent of other factors, suggesting that apneic events and oxygen desaturation during sleep are mechanisms for increased fibrinogen levels in patients with OSA.

The effect of obstructive sleep apnea on olfactory functions

The aim of this study was to investigate the effect of obstructive sleep apnea (OSA) on the parameters of olfactory functions (odor threshold, odor discrimination, and odor identification tests) for orthonasal olfaction, retronasal olfactory testing, and olfactory bulb (OB) volumes. Prospective clinical study. This study was carried out in 78 volunteers between the ages of 20 and 60 years. The mean age of the patients was 46 ± 10.1 years. Patients were divided into three groups according to polysomnography results: 1) a control group, 2) a mild to moderate OSA group, and 3) a severe OSA group. Clinical features of the participants were evaluated with the Epworth Sleepiness Scale. Orthonasal and retronasal olfactory testing were performed with Sniffin' Sticks olfactory testing and retronasal olfactory testing, respectively. Olfactory bulb volumes were measured by planimetric manual contouring on magnetic resonance imaging (MRI). The current investigation produced four major findings: 1) The apnea-hypopnea index had a significant and strong negative correlation with odor threshold scores and odor discrimination scores; 2) The apnea-hypopnea index was significantly negatively correlated with odor identification score and both right and left OB volumes; 3) retronasal olfactory scores were not significantly affected by OSA; and 4) continuous O2 saturation had a significant positive correlation on orthonasal olfactory functions, particularly the odor threshold and discrimination scores. This study demonstrated that OSA had significant negative effects on all orthonasal olfactory tasks, especially on threshold and discrimination. MRI also revealed volumetric shrinkage of OB volumes.

Adjustment of apnea-hypopnea index with severity of obstruction events enhances detection of sleep apnea patients with the highest risk of severe health consequences

Presently, the severity of obstructive sleep apnea (OSA) is estimated based on the apnea-hypopnea index (AHI). Unfortunately, AHI does not provide information on the severity of individual obstruction events. Previously, the severity of individual obstruction events has been suggested to be related to the outcome of the disease. In this study, we incorporate this information into AHI and test whether this novel approach would aid in discriminating patients with the highest risk. We hypothesize that the introduced adjusted AHI parameter provides a valuable supplement to AHI in the diagnosis of the severity of OSA. This hypothesis was tested by means of retrospective follow-up (mean ± sd follow-up time 198.2 ± 24.7months) of 1,068 men originally referred to night polygraphy due to suspected OSA. After exclusion of the 264 patients using CPAP, the remaining 804 patients were divided into normal (AHI < 5) and OSA (AHI ≥ 5) categories based on conventional AHI and adjusted AHI. For a more detailed analysis, the patients were divided into normal, mild, moderate, and severe OSA categories based on conventional AHI and adjusted AHI. Subsequently, the mortality and cardiovascular morbidity in these groups were determined. Use of the severity of individual obstruction events for adjustment of AHI led to a significant rearrangement of patients between severity categories. Due to this rearrangement, the number of deceased patients diagnosed to have OSA was increased when adjusted AHI was used as the diagnostic index. Importantly, risk ratios of all-cause mortality and cardiovascular morbidity were higher in moderate and severe OSA groups formed based on the adjusted AHI parameter than in those formed based on conventional AHI. The adjusted AHI parameter was found to give valuable supplementary information to AHI and to potentially improve the recognition of OSA patients with the highest risk of mortality or cardiovascular morbidity.

Association of Obstructive Sleep Apnea with Peripheral Endothelial Function Assessed by Reactive Hyperemia Index

❙ABSTRACT❙ Background: Obstructive sleep apnea (OSA) has been shown to be an important risk factor for metabolic syndrome and cardiovascular disease. Endothelial dysfunction plays a pivotal role in the pathophysiology of these diseases. However, little is known about the relationship between sleep apnea and microvascular endothelial dysfunction, as assessed by digital reactive hyperemia. Methods: The study population consisted of 80 patients (mean age, 48 ± 12 years-old; 65 men; 59 hypertensive). We measured apnea hypopnea index (AHI) and mild OSA was defined as 5 < AHI <15 and moderate to - severe OSA as AHI 15. Reactive hyperemia index (RHI) derived from peripheral arterial tonometry (PAT) as ≥ measurement of endothelium-mediated vasodilatation. Results: There were 61 OSA patients in the study population (AHI, 21.5 ± 16.7 vs. 2.7 ± 1.6 in non-OSA; p < 0.001). There were no significant difference in RHI and peripheral augmentation index (pAIx) between OSA and non-OSA group (RHI, 2.04 ± 0.48 vs. 2.06 ± 0.42; p = 0.894; pAIx, 21.7% ± 24.0% vs. 21.7% ± 30.0%; p = 1.000, respectively). Also, there was no significant difference in RHI and pAIx between mild (n = 31) and moderate to severe (n = 30) OSA group (RHI, 2.10 ± 0.47 vs. 1.98 ± 0.49; p = 0.333; pAIx, 24.2% ± 20.7% vs. 19.0% ± 27.2%; p = 0.407, respectively), either. Overall, no significant correlation between AHI and RHI was observed (r = -0.023, p = 0.837). The other OSA severity indices such as oxygen desaturation index, mean and minimum oxygen saturation were not correlated with RHI or pAIx. In the subgroup analysis for the OSA group, we could not find any significant relationships between AHI and PAT parameters, either. Conclusions: OSA was not observed to be associated with reactive hyperemia measured by PAT. (J Korean Soc Hypertens 2014;20(2):42-50)

Sleep architecture in school-aged children with primary snoring

ObjectiveWe aimed to examine if sleep architecture was altered in school-aged children with primary snoring (PS). MethodsChildren ages 6 to 13years from 13 primary schools were randomly recruited. A validated obstructive sleep apnea (OSA) screening questionnaire was completed by their parents. Children at high risk for OSA and a randomly chosen low-risk group were invited to undergo overnight polysomnography (PSG) and clinical examination. Participants were classified into healthy controls, PS, mild OSA, and moderate to severe OSA (MS OSA) groups for comparison. ResultsA total of 619 participants underwent PSG (mean age, 10.0±1.8years; 396 (64.0%) boys; 524 (84.7%) prepubertal). For the cohort as a whole, there were no significant differences in measures of sleep architecture between PS and nonsnoring healthy controls. In the multiple regression model, percentage of nonrapid eye movement (NREM) stage 1 (N1) sleep had a significantly positive association, whereas percentage of slow-wave sleep (SWS) had a significantly negative association with sleep-disordered breathing (SDB) severity after controlling for age, gender, body mass index (BMI) z score, and pubertal status. In prepubertal children with PS, no significant disruption of sleep architecture was found. However, pubertal adolescent PS participants had significantly higher adjusted percentage of N1 sleep and wake after sleep onset (WASO) compared to healthy controls. ConclusionsPS did not exert significant adverse influences on normal sleep architecture in prepubertal school-aged children. Nevertheless, pubertal adolescents with PS had increased N1 sleep and WASO.

Sleep apnea and sexual dysfunction

Obstructive sleep apnea (OSA) is associated with various health-related consequences. Recently, erectile dysfunction (ED) and other sexual dysfunction in men have been shown to associate with snoring and sleep apnea. However, it is still unknown what factors of sleep apnea produce sexual problems. Data collected from 62 male patients undergoing in-lab polysomnography for suspected snoring or sleep apnea. Sexual function was assessed by 15-item International index of Erectile Function (IIEF-15) questionnaire. IIEF-15 has five sub domains: erectile function, intercourse satisfaction, orgasmic function, sexual desire, and overall satisfaction. We compared each sub domain and total scores between severe (AHI > 30, n = 30) and mild-to-moderate (5 < AHI < 30, n = 32) OSA groups. 40% of all OSA patients had good sexual function (total score 60–75) and 25% had poor function (score 5–43). ED ( < 25) was present in 60% of patients with severe group, and 35% of patients with mild-to-moderate group, although these groups are almost same ages (45.5 vs 44.6). Severe OSA group had more general sexual dysfunction comparing to mild-to-moderate group (45.6 vs 50). Similar results were obtained for each sub domains. severe OSA group got lower score than mild-to-moderate group. Erectile dysfunction and sexual dysfunction were prevalent in Korean OSA patients. Severe OSA group got lesser score for sexual function than mild-to-moderate OSA group, suggesting that severe OSA with high AHI is related with sexual dysfunction. The Author declare that there is no conflict of interest.

Severity of sleep apnea syndrome is associated with arterial stiffness in elderly population

Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality, and higher arterial stiffness is one of the biological markers for increased cardiovascular risk in OSA. However, with aging, several cardiovascular comorbidities and treatments may confound the relationship between OSA and arterial stiffness. Therefore, we sought to investigate the association between OSA and arterial stiffness in otherwise healthy elderly population. We performed a cross-sectional study of 476 elderly patients ( ⩾ 60 yr) recruited from community and the sleep clinic in a university hospital between November 2010 and January 2013. Clinical data were collected using a standardized protocol, including questions about current medical condition and its medication. OSA was diagnosed using laboratory polysomnography. Subjects were stratified into two groups according to the presence of comorbid medical conditions or its treatment, such as, hypertension, diabetes, and dyslipidemia. Each group was subdivided into three groups based on apnea-hypopnea index (AHI), consisting of normal (AHI < 15), mild-to-moderate OSA (15 ⩽ AHI ⩽ 30), and severe OSA (AHI > 30). Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI). Among 476 participants, 101 subjects were without any comorbid medical condition or medication use. The baPWV, CAVI, CRP were significantly higher in patients with severe OSA group after adjustment for gender, body mass index and smoking status ( P = 0.003, 0.001, and 0.025 by ANCOVA, respectively) in healthy elderly group, but not in comorbid group. Multiple regression analysis showed baPWV, CAVI, and C-reactive protein had linear association with AHI ( β = 0.326, P = 0.002; β =0.326, P = 0.002; β = 3.253, P = 0.002, respectively) in healthy group. The severity of OSA is associated with arterial stiffness in otherwise healthy elderly individuals with OSA, but not in comorbid OSA individuals. In exploring the association between OSA and cardiovascular complications in the elderly, comorbidities need to be controlled, and we have found that OSA still increases cardiovascular risk in the elderly. This study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 2010–0008886).

Circulating FABP4 and subclinical atherosclerosis in obstructive sleep apnea syndrome

Introduction Obstructive sleep apnea (OSA) is associated with high cardiovascular risk. Carotid intimae media thickness (cIMT) is a surrogate marker of subclinical atherosclerosis. Circulating adipocyte fatty acid-binding protein (FABP4) levels have been associated with metabolic alterations and increased cardiovascular morbidity. Our aim was to evaluate circulating FABP4 concentrations and cIMT in OSA patients. Materials and methods We included 125 participants, aged 18–75, referred by suspected OSA to our Sleep Disorders Unit. OSA was assessed by overnight polysomnography (PSG). Circulating FABP4 levels were determined by ELISA and cIMT was measured by ultrasonography. Results Circulating FABP4 levels were higher in the presence of OSA (25.8 ± 9.7 vs. 19.1 ± 7.9 μ g/l, p = 0.003) and according to OSA severity (overall p = 0.017). The presence of atheromatous carotid plaque as well as cIMT mean values were both higher in OSA compared to non OSA participants (48% vs. 2%, p = 0.004 and 665.4 ± 120.1 vs. 581.3 ± 78.1 μ m, p = 0.005, respectively). cIMT did not differ between OSA severity groups. Moreover, FABP4 levels were positively correlated with cIMT (r = 0.341, p 0.001). Conclusion FABP4 is associated to OSA presence and severity. FABP4 is a biomarker of metabolic comorbidities in OSA patients. The carotid ultrasonography in these patients can reliably report of the precociousness of arteriosclerotic phenomenon. However, more studies are needed before this technique is widespread in our sleep units. Acknowledgements SOCAP, SEPAR and CIBERDEM.

Gender‐Related Changes of the Epicardial Fat Thickness and Leptin in Obstructive Sleep Apnea

Epicardial fat thickness (EFT), an indicator of visceral obesity, and leptin are 2 novel markers for studying the obstructive sleep apnea (OSA) population. This study aimed to investigate the effects of gender on leptin levels and EFT, and the relation with OSA severity. A total of 149 patients with OSA (female/male 55/94 and mean age 50.8 ± 9.2 years) and 50 control patients (female/male 24/26 and mean age 48.9 ± 8.8 years) were included in the study. The study population was divided into 4 groups according to apnea/hypopnea index (AHI) as control (AHI <5), the mild OSA (AHI 5-14), the moderate OSA (AHI 15-29), and the severe OSA (AHI ≥30). EFT was obtained from parasternal long-axis and parasternal short-axis echocardiographic images. Leptin levels among females were significantly higher than among males (10.5 [7.8] vs. 5.4 [4.5] ng/mL, P = 0.001, respectively). Among women, leptin levels were significantly higher in the severe OSA group compared to the control group (9.8 [9.0] vs. 15.5 [10.1] ng/mL, P = 0.05, respectively). Conversely, no relation was observed between OSA severity and the leptin levels among men. EFT was not significantly different between the 2 genders (P > 0.05). EFT was thicker in the severe OSA group than in the control and mild OSA groups among women, whereas EFT was not changed according to OSA severity among males (P > 0.05). Leptin and EFT may be a valuable parameter in the evaluation of OSA severity in women than in men.

Mortality of Patients with Obstructive Sleep Apnea in Korea

Obstructive sleep apnea (OSA) is associated with diverse health risks, including death. However, the role of OSA as a risk factor for death has never been studied in Asians. This study is aimed at evaluating the influence of OSA on the mortality in Korean sleep clinic population. A total of 2,240 patients who underwent in-laboratory full-night polysomnography due to snoring or sleep apnea were included. The patients were categorized based on apnea-hypopnea index (AHI)/hour. Death records were provided from the Statistics Korea. A Cox-proportional hazard regression model and Kaplan-Meier survival curve were used for analysis and demonstration of the all-cause mortality and cardiovascular mortality. The all-cause mortality risk adjusted for age, sex, body mass index, diabetes, hypertension, cardiovascular diseases, and previous history of stroke was significantly associated with the increased severity of OSA. The adjusted hazard ratio (HR) for all-cause mortality in the severe OSA group (AHI ≥ 30) vs. reference group (5 < AHI) was 2.47 (95% confidence interval [CI], 1.09-5.57) and the adjusted HR for cardiovascular mortality was 4.66 (CI 1.03-21.08). After adjusting for whether the patients were treated or untreated, the HR for all-cause and cardiovascular mortality in the severe OSA group vs. reference group were 2.14 (p = 0.079) and 4.19 (p = 0.076), respectively. The present study showed that the increased mortality was also associated with the increased severity of OSA in Koreans as shown in the studies performed in the Western countries.