Obstructive Sleep Apnea Markers Research Articles

Phase-Amplitude Coupling in Theta and Beta Bands: A Potential Electrophysiological Marker for Obstructive Sleep Apnea.

Phase-amplitude coupling (PAC) between the phase of low-frequency signals and the amplitude of high-frequency activities plays many physiological roles and is involved in the pathological processed of various neurological disorders. However, how low-frequency and high-frequency neural oscillations or information synchronization activities change under chronic central hypoxia in OSA patients and whether these changes are closely associated with OSA remains largely unexplored. This study arm to elucidate the long-term consequences of OSA-related oxygen deprivation on central nervous system function. : We screened 521 patients who were clinically suspected of having OSA at our neurology and sleep centers. Through polysomnography (PSG) and other clinical examinations, 103 patients were ultimately included in the study and classified into mild, moderate, and severe OSA groups based on the severity of hypoxia determined by PSG. We utilized the phase-amplitude coupling (PAC) method to analyze the modulation index (MI) trends between different frequency bands during NREM (N1/N2/N3), REM, and wakefulness stages in OSA patients with varying severity levels. We also examined the correlation between the MI index and OSA hypoxia indices. Apart from reduced N2 sleep duration and increased microarousal index, the sleep architecture remained largely unchanged among OSA patients with varying severity levels. Compared to the mild OSA group, patients with moderate and severe OSA exhibited higher MI values of PAC in the low-frequency theta phase and high-frequency beta amplitude in the frontal and occipital regions during N1 sleep and wakefulness. No significant differences in the MI of phase-amplitude coupling were observed during N2/3 and REM sleep. Moreover, the MI of phase-amplitude coupling in theta and beta bands positively correlated with hypoxia-related indices, including the apnea-hypopnea index (AHI) and oxygenation desaturation index (ODI), and the percentage of oxygen saturation below 90% (SaO2<90%). OSA patients demonstrated increased MI values of theta phase and beta amplitude in the frontal and occipital regions during N1 sleep and wakefulness. This suggests that cortical coupling is prevalent and exhibits sleep-stage-specific patterns in OSA. Theta-beta PAC during N1 and wakefulness was positively correlated with hypoxia-related indices, suggesting a potential relationship between these neural oscillations and OSA severity. The present study provides new insights into the relationship between neural oscillations and respiratory hypoxia in OSA patients.

The Contribution of Insomnia and Obstructive Sleep Apnea on the Transition from Acute to Chronic Painful Temporomandibular Disorders and their Persistence: A Prospective 3-Month Cohort Study

ABSTRACT Background Insomnia, and Excessive Daytime Sleepiness (EDS), a surrogate marker of Obstructive Sleep Apnea (OSA), are common sleep-related conditions among painful temporomandibular disorders (TMD) patients. OSA was found to increase the risk of chronic painful TMD. Aims This prospective cohort study aims to determine the contribution of insomnia and EDS on acute to chronic painful TMD transition as well as its persistence when chronic pain is defined by: (i) duration (> 3 months), and (ii) dysfunction (Graded Chronic Pain Scale [GCPS II-IV]). Methods From 456 patients recruited between 2015 to 2021, through four locations in Canada, 378 completed the follow-up. A diagnosis was obtained using the Research Diagnostic Criteria or the Diagnostic Criteria for TMD. Insomnia was assessed with the Insomnia Severity Scale (ISS), and OSA was assessed using the Epworth Sleepiness Scale (ESS) which measures EDS, both at baseline. Patients completed the GCPS form at baseline and 3-month follow-up. Results Borderline associations were found between EDS and the transition or persistence of chronic painful TMD when chronic pain was defined by pain duration (RR adjusted_duration = 1.11, P = 0.07) and dysfunction (RRadjusted_dysfunction =1.40, P = 0.051). Furthermore, EDS was specifically associated with persistent painful TMD when chronic pain was defined by pain duration (RR = 1.13, 95%CI: 1.00-1.26, P = 0.04). Insomnia was not related to the study outcomes (RRadjusted_duration = 0.94, P = 0.27, RRadjusted_dysfunction =1.00, P = 0.99). Conclusion Results indicate that EDS contrary to insomnia predicted the persistence of chronic painful TMD at a 3-month follow-up.

Association between Arterial Hypertension and Laboratory Markers, Body Composition, Obstructive Sleep Apnea and Autonomic Parameters in Obese Patients.

Systemic arterial hypertension (SAH) is a multifactorial disease, highly prevalent and associated with health risks. The purpose of this study was to investigate the association between SAH and laboratory, anthropometric, heart rate variability (HRV), and obstructive sleep apnea markers and, secondarily, to analyze the sensitivity and specificity of the variables that are independent factors in the association. Cross-sectional study with 95 obese patients treated at an obesity referral clinic in Salvador, BA, Brazil. SAH data were obtained from electronic medical records. The sample was stratified in the Normotensive Group (NG) and the Hypertensive Group (HG), and laboratory markers, body composition, polysomnography, and HRV were measured to evaluate the association of SAH with the predictor variables. For the analysis, p<0.05 was adopted. The average age of the NG was 36.3 ± 10.1 and HG 40.4 ± 10.6 years; 73.7% were women in the NG and 57.9% in HG; 82.4% in HG had insulin resistance. In the multivarious logistics regression model with adjustments in age, sex, height, and oxyhemoglobin saturation, SAH was inversely associated with fasting plasma glucose mg/dL (odds ratio [OR] = 0.96; 95% confidence interval [CI] = 0.92-0.99) and visceral fat area (VFA) cm2(OR = 0.98; 95% CI = 0.97-0.99). The area under the VFA curve was 0.728; CI 95% (0.620-0.836); fasting plasma glucose 0.693;CI 95% (0.582-0.804). Lower VFA and fasting plasma glucose concentrations were inversely associated with SAH. In addition, fasting plasma glucose and VFA showed a high sensitivity for SAH screening.

COVID-19 Pandemic-Related Sleep and Mental Health Disparities among Students at a Hispanic and Minority-Serving Institution.

Background: The COVID-19 pandemic has impacted nearly all sectors of our population, including college students, who continue to share disproportionate rate of disparities. In this study, we aimed to identity key sleep health characteristics, including markers for obstructive sleep apnea, as well as its relation to mental health, physical health, and academic performance. Methods: A cross-sectional study design with online survey dissemination was used. Descriptive, bivariate, and multivariable binary logistic regression analyses were conducted among a predominantly minority population. Results: Results show that nearly 78% of the population reported that the pandemic impacted their mental or physical health, while over 83% reported daytime tiredness/fatigue/sleepiness, and another 61% reported sleeping less than seven hours during weekdays. Among other associations, pandemic-related poor sleep health, including sleeping less than seven hours, was associated with daytime tiredness/fatigue/sleepiness, psychological distress, as well as low mental health and physical health. A severe marker for obstructive sleep apnea, having stopped breathing during sleep, was also associated with psychological distress during the pandemic. Conclusions: Sleep health interventions are critical for optimizing college student health and well-being, including improving mental health outcomes.

Association of Obstructive Sleep Apnea Indicators with Heart Failure

Background: Obstructive sleep apnea (OSA) occurs when the airway is repeatedly blocked during sleep, resulting in frequent brief awakenings throughout the night. OSA has been found to increase the risk of many cardiovascular diseases, especially heart failure (HF). HF with reduced, preserved, and borderline ejection fraction (HFrEF, HFpEF, and HFbEF) are three subtypes common in OSA patients. The aim of this study is to further explore the relationship between OSA and HF and the influence of specific OSA measures.&#x0D; Methods: Electronic medical data was collected from health histories, echocardiograms, and polysomnography studies. Observations were sorted into three categories based on left ventricular ejection fraction: HFpEF (n=334), HFrEF (n=77), and HFbEF (n=37). Multinomial logistic regression was then conducted to determine the relative risk of HFpEF and HFrEF from each variable as compared to the baseline HFbEF.&#x0D; Results: Pacemaker presence, previous stroke, BMI, and a measure of left ventricular dysfunction (LVD), called relative wall thickness, all raised the risk of HFpEF compared to HFbEF, while another LVD measure, left ventricular end-systolic dimension, reduced it. These factors also increased risk for HFrEF, except for previous stroke and pacemaker presence, which were not significant. Relevant OSA metrices included average blood oxygen saturation and three measures of sleep apnea severity, named central apnea index, hypopnea index per hour, and the Epworth Sleepiness Scale (ESS). These all decreased relative HFpEF risk, other than ESS, which raised it.&#x0D; Conclusions: As was expected, several standard HF predictors increased the risk of both types of HF. Surprisingly, few OSA indices had the same effect. This suggests that targeting specific OSA markers may not be effective in treating patients with any of these HF types. Future work could involve the influence of OSA and its indices on mortality, or the responses of these indicators to treatment, both topics with limited previous findings.

Obstructive Sleep Apnea and Non-alcoholic Fatty Liver Disease in Obese Patients Undergoing Bariatric Surgery.

Morbid obesity is associated with multiple comorbidities including obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD). It has been suggested that OSA may contribute to NAFLD pathogenesis due to intermittent nocturnal hypoxia. The objective of this study was to assess the apnea-hypopnea index (AHI) and lower minimum oxygen saturation, markers of OSA, in patients undergoing bariatric surgery (BSx) with perioperative liver biopsy to detect NAFLD. This was a single center cross-sectional study of 61 patients undergoing BSx who consented to have a perioperative wedged liver biopsy. Biochemical, clinical, anthropometric variables, and a sleep study test were performed prior to BSx. NAFLD was diagnosed in 49 (80.3%) patients; 12 had normal liver (NL). Those with NAFLD had significantly higher (p < 0.05) AST (42.6 vs 18.1U/L) and ALT (35.0 vs 22.1U/L) but similar clinical, anthropometric, and metabolic parameters to NL. There was a higher AHI (32.03 vs 14.35) and significantly lower minimum oxygen saturation (SaO2) (78.87 vs 85.63) in NAFLD compared with NL (p < 0.05). When assessing associations between OSA parameters and liver histology in NAFLD, AHI correlated significantly with lobular inflammation (p < 0.05). In a multivariate analysis, BMI was significantly correlated with lobular inflammation with mean SaO2 nearing significance. These results indicate that in a homogeneous bariatric population sample with similar characteristics, those with NAFLD had higher AHI and lower minimum SaO2 compared with NL. AHI correlated with liver inflammation suggesting a potential role for intermittent nocturnal hypoxia in the pathogenesis and progression of NAFLD.

Serum hypoxia-inducible factor-1α protein level as a diagnostic marker of obstructive sleep apnea.

Serum hypoxia-inducible factor-1α protein level as a diagnostic marker of obstructive sleep apnea.

The estimation of excessive daytime sleepiness in post-stroke patients - a polysomnographic study

Abstract Excessive daytime sleepiness (EDS) has been reported in stroke patients. EDS in acute stroke was studied repeatedly, but there is a modest amount of data in post-stroke patients. The aim of this study was to assess the frequency of EDS and characterize sleep architecture in patients >3 months after stroke and identify factors which may affect EDS. 66 patients were enrolled, of which 33 had experienced stroke. All underwent a standardized overnight, diagnostic single night polysomnography, including electrocephalogram (EEG) leads, electrooculograms (EOG), chin electromyogram (EMG), and electrocardiogram (ECG). Epworth Sleepiness Scale (ESS) was used to measure subjects’ level of daytime sleepiness. We observed similar total ESS score, total sleep time (TST), sleep efficiency, as well as respiratory disturbance index /apnea-hypopnea index (RDI/AHI), oxygen desaturation index (ODI) and mean heart rate in both groups. We observed positive linear correlation between EDS and mean heart rate in the stroke group (r = 0.46, p In summary, in stroke patients subjective daytime sleepiness is associated with heart rate, but not with the severity of OSA. Thus ESS (Epworth Scale Score) may be not as useful as a marker of obstructive sleep apnea (OSA) presence or severity in post stroke patient as in the general population.

The estimation of excessive daytime sleepiness in post-stroke patients - a polysomnographic study

Excessive daytime sleepiness (EDS) has been reported in stroke patients. EDS in acute stroke was studied repeatedly, but there is a modest amount of data in post-stroke patients. The aim of this study was to assess the frequency of EDS and characterize sleep architecture in patients >3 months after stroke and identify factors which may affect EDS.66 patients were enrolled, of which 33 had experienced stroke. All underwent a standardized overnight, diagnostic single night polysomnography, including electrocephalogram (EEG) leads, electrooculograms (EOG), chin electromyogram (EMG), and electrocardiogram (ECG). Epworth Sleepiness Scale (ESS) was used to measure subjects’ level of daytime sleepiness.We observed similar total ESS score, total sleep time (TST), sleep efficiency, as well as respiratory disturbance index /apnea-hypopnea index (RDI/AHI), oxygen desaturation index (ODI) and mean heart rate in both groups. We observed positive linear correlation between EDS and mean heart rate in the stroke group (r = 0.46, p < 0.05) as well as between EDS and REM duration (r = 0.23, p < 0.05). In the non-stroke group EDS didn’t correlate with the heart rate or with the REM duration. In the non-stroke group EDS correlated positively with RDI/AHI and ODI index (r = 0.46; p = <0.05 r = 0.41, p < 0.05 and maximal desaturation (r = 0.55, p < 0.05), this correlation was not observed in post-stroke group. In the both groups we observed negative linear correlation between BMI and saturation (stroke group - mean as well as minimal saturation (r = −0.458, p < 0.05; r = −0.578, p < 0.05), non stroke group - minimal but not mean saturation rate (r = −0.544, p < 0.05). We also noticed in both groups positive correlation between BMI and both AHI and ODI index (stroke group respectively: r = 0.430, p < 0.05; r = 0.451, p < 0.05; non-stroke group - BMI and ODI: r = 0.405, p < 0.05). The positive BMI correlation with RDI/AHI was not significant in the non-stroke group. We noticed that BMI correlates with non-REM sleep N1 (r = 0.760, p < 0.05) in post-stroke group, while it correlates negatively with REM sleep (r = -0.709, p < 0.05). There was no such correlation in the non-stroke group.In summary, in stroke patients subjective daytime sleepiness is associated with heart rate, but not with the severity of OSA. Thus ESS (Epworth Scale Score) may be not as useful as a marker of obstructive sleep apnea (OSA) presence or severity in post stroke patient as in the general population.

Potential Anatomic Markers of Obstructive Sleep Apnea in Prepubertal Children.

Adenotonsillar hypertrophy is the major cause of obstructive sleep apnea (OSA) in prepubertal children, but children without enlarged lymphoid tissues may still suffer from OSA. This study aimed to identify other potential anatomic features associated with childhood OSA. This prospective study took place between January 2010 and April 2014. Prepubertal children suspected to have OSA, aged 6 to 11 years, were recruited. They underwent anthropometric measurements, nocturnal polysomnography, tonsil size evaluation, x-ray cephalometry, and sonographic measurement of lateral parapharyngeal wall (LPW) thickness. Linear regression analyses were used to test for the association between anatomic measurements and OSA severity. Logistic regression analyses were used to identify potential anatomic markers for different cutoffs (obstructive apneahypopnea index (OAHI) ≥ 1 and ≥ 5 events/h) for OSA. Forty-seven children with OSA (20 with moderate to severe disease) and 43 children for the control group were recruited. Sonographic measurement of LPW thickness and position of hyoid bone taken from x-ray cephalometry were risk factors associated with OSA. Linear regression analyses found that these two phenotypes were associated with OAHI. Multivariate models adjusted for age, sex, body mass index, z score, and tonsil size revealed that lower position of hyoid bone was independently associated with higher risk for OSA, whereas both lower position of hyoid bone and greater LPW thickness were associated with higher OAHI and also a higher risk for moderate to severe OSA. Position of hyoid bone and LPW thickness are anatomical markers of childhood OSA independent of obesity and tonsil size. Screening tools may include cephalometry and sonographic measurement of LPW to allow better delineation of OSA risk.

A3440 rs1275988 and rs2586886 in TASK-1 gene may be a protective genetic markers of Obstructive Sleep Apnea in obese patients

Objectives: Acid-sensitive K+ channels (TASK-1) are sensitive to changes in extracellular pH in the physiological range, which have been implicated in peripheral and central respiratory chemosensitivity. We sought to assess the association between the human TASK-1 genetic polymophisms and obstructive sleep apnea (OSA). Methods: 154 severe OSA patients and 156 non-OSA individuals were collected baseline characteristics and genotyped for rs1275988 and rs2586886 single nucleotide polymorphisms (SNPs) of the human TASK-1 gene by a Kompetitive Allele Specific PCR genotyping system. The association between genotypes and OSA status was assessed. Results: No significant differences in the genotype distribution and allele frequencies of SNPs (rs1275988 and rs2586886) were found between severe OSA patients and non-OSA groups. Stratified by BMI, the distribution of SNPs (rs1275988 and rs2586886) genotype distribution, allele frequencies, recessive model (GG+GA vs AA) and dominant model (GG vs AA + GA) showed a significant difference between severe OSA groups and non-OSA groups in patients with BMI≥28 kg/m2 (for genotype: P = 0.034 and P = 0.025, respectively; for allele: P = 0.007 and P = 0.002, respectively; for Recessive model: P = 0.027 and P = 0.013, respectively; for dominant model: P = 0.038 and P = 0.046, respectively). The multivariate logistic regression analysis showed that the AA genotype was a protective factor for OSA[for rs1275988:OR = 0.340 (95% CI: 0.120–0.966; for rs2586886: OR = 0.283 (95%CI:0.097–0.832) respectively]. Conclusion: The rs1275988 and rs2586886 SNPs in TASK-1 may be a protective genetic markers to OSA in obese patients.

Frequency of Loud Snoring and Metabolic Syndrome among Korean Adults: Results from the Health Examinees (HEXA) Study.

Studies regarding the association between snoring and metabolic abnormalities have been inconsistent. We examine whether snoring frequency and obstructive sleep apnea markers are associated with metabolic syndrome (MetS) among Koreans aged 40–69 years. A total of 72,885 subjects (24,856 men, 48,029 women) from the Health Examinees Gem study between 2009 and 2013 were included. Snoring frequency was grouped into five categories (never, 1–3/month, 1–3/week, 4–5/week, 6+/week). Obstructive sleep apnea markers included breathing interruptions and awakenings. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated through logistic regression. Compared with non-snorers, those who snore 6+/week were associated with increased odds for MetS (OR: 2.07, 95% CI: 1.91–2.25, p-trend < 0.0001 among men; OR: 1.45, CI: 1.33–1.58, p-trend < 0.0001 among women). Snoring frequency is associated with MetS and its components in both men and women. Snoring and obstructive sleep apnea markers are important indicators of sleep quality, which may facilitate early detection of sleep disorders and further complications such as MetS.

Is C-reactive protein a marker of obstructive sleep apnea?: A meta-analysis.

Background:Obstructive sleep apnea (OSA) is a common disease, distinguished by recurrent episodes of upper airway obstruction during sleep, with an inflammatory component. C-reactive protein (CRP) and high-sensitivity C-reactive protein (hs-CRP) are markers of systemic inflammation and may serve as biomarkers of OSA.Methods:Scientific studies published from January 1, 2006, to January 1, 2016 were obtained via searches of PubMed, Embase, SCI, and China National Knowledge Internet (CNKI) using relevant terms. Studies concerning serum CRP level/ hs-CRP in OSA patients were reviewed by 2 independent reviewers. Studies were included if they conform with our specific criteria of inclusion. Eligible studies were subjected to quality review, data extraction, and meta-analysis by using RevMan (version 5.2) and STATA (version 12.0).Results:There were 15 studies that met inclusion criteria that included a total of 1297 subjects. Meta-analysis revealed that serum CRP levels in the OSA group were 1.98 mmol/L higher than those in control group (95% confidence interval: 1.39–2.58, P < .01). Similarly, serum hs-CRP levels in the OSA group were 1.57 mmol/L higher than that in the control group (95% confidence interval: 0.96–2.18, P < .01). Subgroup analysis showed greater differences between OSA patients and controls in the setting of obesity (body mass index)> = 30. The total weighted mean difference (WMD) between OSA and controls within the subgroup of subjects who had a CRP was 2.10; for hs-CRP, the WMD was 2.49. Comparing OSA patients of mean apnea hypopnea index> = 15 and controls, the total WMD for the CRP subgroup was 2.19; for the hs-CRP subgroup, the WMD was 1.70.Conclusion:In our meta-analysis, serum CRP/hs-CRP levels were discovered to be higher in OSA patients compared with control subjects. Those with higher body mass index and apnea hyponea index demonstrated larger differences in CRP/hs-CRP levels. These data are consistent with an inflammatory component of OSA pathophysiology and support the role of CRP/hs-CRP as a biomarker in this disease.

Sleep duration, daytime napping, markers of obstructive sleep apnea and stroke in a population of southern China.

Sleep habits are associated with stroke in western populations, but this relation has been rarely investigated in China. Moreover, the differences among stroke subtypes remain unclear. This study aimed to explore the associations of total stroke, including ischemic and hemorrhagic type, with sleep habits of a population in southern China. We performed a case-control study in patients admitted to the hospital with first stroke and community control subjects. A total of 333 patients (n = 223, 67.0%, with ischemic stroke; n = 110, 23.0%, with hemorrhagic stroke) and 547 controls were enrolled in the study. Participants completed a structured questionnaire to identify sleep habits and other stroke risk factors. Least absolute shrinkage and selection operator (Lasso) and multiple logistic regression were performed to identify risk factors of disease. Incidence of stroke, and its subtypes, was significantly associated with snorting/gasping, snoring, sleep duration, and daytime napping. Snorting/gasping was identified as an important risk factor in the Lasso logistic regression model (Lasso’ β = 0.84), and the result was proven to be robust. This study showed the association between stroke and sleep habits in the southern Chinese population and might help in better detecting important sleep-related factors for stroke risk.

Erectile dysfunction is a marker for obstructive sleep apnea

Purpose: To investigate the prevalence of erectile dysfunction (ED) in patients with obstructive sleep apnea (OSA) with and without any other comorbidities.Methods: The patient group was newly diagnosed as having OSA (apnea–hypopnea index [AHI] > 5/h) using a polysomnographic examination. A group of subjects with simple snoring were included into the control group. Clinically relevant comorbidities were systematically assessed in face-to-face interviews. All patients were asked to complete the 15-item International Index of Erectile Function (IIEF-15) questionnaire for the evaluation of ED. The patients with OSA and ED were evaluated according to these comorbidities.Results: Of the 94 patients, 39 patients were excluded because of severe diseases. OSA was observed in 38 (69.1%) of the 55 patients. ED was seen in 24 (63.2%) patients with OSA, and in 8 (47.1%) patients without OSA (p > 0.05). There were no statistical differences between the groups’ ages, IIEF scores, and body mass index (BMI) scores. There were statistically significant differences between the groups’ AHI scores (p < 0.05). There was a significant correlation between the groups’ AHI scores, BMI, and age (p < 0.05). There was no statistically significant difference in patients with OSA, with and without comorbidity in terms of ED.Conclusion: The rate of ED was higher in patients with OSA who had no other comorbidities. Therefore, ED can be a sensitive marker of OSA.

Study of Exhaled Nitric Oxide in Subjects with Suspected Obstructive Sleep Apnea: A Pilot Study in Vietnam.

Background and Objective. The concentration of exhaled nitric oxide (eNO), reflecting the activity of inducible NO synthase in airway epithelium, has been found to increase in patients with obstructive sleep apnea (OSA). This study aimed to measure eNO concentration in patients with suspected OSA and to correlate different eNO parameters with clinical and sleep apnea characteristics. Methods. In this cross-sectional study, all patients underwent in-lab overnight polysomnography (PSG) and eNO measurement using a method of multiple flow rates before and after PSG (pre- and post-PSG). Results. According to the result of PSG, 82 persons were divided into two groups: control subjects (n = 30; 54 ± 14 years) and patients with OSA defined as apnea-hypopnea index (AHI) ≥ 5/hour (n = 52; 53 ± 12 years). Body mass index (BMI) and neck and abdomen circumferences of OSA patients were significantly higher than those from control subjects. In OSA group, post-PSG alveolar NO concentration (CANO) (5.3 ± 1.9 ppb) was significantly higher than pre-PSG CANO (4.0 ± 1.7 ppb; P < 0.001). Significant correlations have been found between CANO and AHI (P < 0.001) and between CANO and nadir SpO2 (P < 0.05). The daytime CANO value of more than 4.1 ppb can be used to screen symptomatic subjects for the presence of OSA with a high specificity of 93.3%. Conclusion. Our findings indicate CANO as a surrogate marker for OSA in persons with suggestive symptoms.

Abstract MP69: Relationships Between Sleep Apnea, Cardiovascular Disease Risk Factors, and Aortic Pulse Wave Velocity over 9 Years: The Wisconsin Sleep Cohort

Background: Cardiovascular disease (CVD) risk factors associated with obstructive sleep apnea (OSA) contribute to endothelial dysfunction and arterial stiffening. We hypothesized that OSA severity would predict aortic pulse wave velocity (PWV) after nearly a decade of aging in the Wisconsin Sleep Cohort (WSC). Methods: Subjects were 596 participants in the WSC that underwent overnight polysomnography between 2000 and 2008; subsequent tonometry data was acquired a mean of 8.8 (standard deviation, 2.1) years later. OSA severity was described by the apnea-hypopnea index (AHI), mean and minimum nocturnal blood oxygen saturation level (SaO 2 , %), and time with SaO 2 &lt;90%. AHI+1 was log transformed. Participants using positive airway pressure therapy (PAP) at the tonometry visit were evaluated as a distinct categorical variable. Non-invasive applanation tonometry was used to derive aortic (carotid-to-femoral) PWV. Multivariable linear and logistic regression models that included CVD risk factors, antihypertensive, and lipid medications were fit to evaluate longitudinal associations between baseline OSA markers and future PWV. Results: At baseline, the 596 participants were mean 55.9 (7.3) years old (53% male, 97.5% Caucasian). Their mean body-mass index (was 31.4 (6.9) kg/m 2 , 89 (14.9%) had diabetes mellitus, and 252 (42.3%) were hypertensive. Excluding the 40 CPAP users, the mean AHI was 5.8 (7.6) events/hour (range 0.0-53.6); 54 (9.1%) had AHI ≥15 events/hr. Mean SaO 2 was 94.7% (2.1%) and minimum SaO 2 was 82.8% (9.5%). Time with SaO 2 &lt;90% did not predict PWV. In models adjusted for age and sex, lower mean SaO 2 (β=-0.16, SE 0.06, p=0.004), lower minimum SaO 2 (β=-0.04, SE 0.01, p=0.005) and higher log 10 (AHI+1) (β=0.55, SE 0.20, p=0.005) predicted higher PWV a mean of approximately 9 years after OSA assessment. However, none of these associations were statistically significant after waist circumference (p≤0.005 for all 3 outcomes) and height were added to the models. For models with mean SaO 2 , waist circumference independently predicted PWV, but after addition of CVD risk factors, only age (β=0.14, SE 0.01, p&lt;0.001), systolic blood pressure (β=0.02, SE 0.01, p&lt;0.001), and diabetes status (β=0.96, SE 0.28, p=0.002) were independent predictors. Very similar results were observed for models with minimum Sa0 2 and PWV. None of the OSA parameters interacted with age or smoking status to predict PWV. Presence of Metabolic Syndrome did not predict PWV; it did not interact with OSA parameters to predict PWV. Conclusions: The longitudinal associations between OSA and PWV are confounded by body size and influenced by diabetes mellitus and blood pressure. These results suggest that weight management and blood pressure control may help prevent arterial stiffening associated with sleep apnea.

Genetic variants associated with sleep disorders

ObjectiveThe diagnostic boundaries of sleep disorders are under considerable debate. The main sleep disorders are partly heritable; therefore, defining heritable pathophysiologic mechanisms could delineate diagnoses and suggest treatment. We collected clinical data and DNA from consenting patients scheduled to undergo clinical polysomnograms, to expand our understanding of the polymorphisms associated with the phenotypes of particular sleep disorders. MethodsPatients at least 21 years of age were recruited to contribute research questionnaires, and to provide access to their medical records, saliva for deoxyribonucleic acid (DNA), and polysomnographic data. From these complex data, 38 partly overlapping phenotypes were derived indicating complaints, subjective and objective sleep timing, and polysomnographic disturbances. A custom chip was used to genotype 768 single-nucleotide polymorphisms (SNPs). Additional assays derived ancestry-informative markers (eg, 751 participants of European ancestry). Linear regressions controlling for age, gender, and ancestry were used to assess the associations of each phenotype with each of the SNPs, highlighting those with Bonferroni-corrected significance. ResultsIn peroxisome proliferator-activated receptor gamma, coactivator 1 beta (PPARGC1B), rs6888451 was associated with several markers of obstructive sleep apnea. In aryl hydrocarbon receptor nuclear translocator-like (ARNTL), rs10766071 was associated with decreased polysomnographic sleep duration. The association of rs3923809 in BTBD9 with periodic limb movements in sleep was confirmed. SNPs in casein kinase 1 delta (CSNK1D rs11552085), cryptochrome 1 (CRY1 rs4964515), and retinoic acid receptor-related orphan receptor A (RORA rs11071547) were less persuasively associated with sleep latency and time of falling asleep. ConclusionsSNPs associated with several sleep phenotypes were suggested, but due to risks of false discovery, independent replications are needed before the importance of these associations can be assessed, followed by investigation of molecular mechanisms.

Use of a simple clinical tool for airway assessment to predict adverse pregnancy outcomes.

Obstructive sleep apnea (OSA) is a risk factor for adverse perinatal outcomes. We aimed to test the hypothesis that maternal Mallampati class (MC), as a marker for OSA, is associated with adverse perinatal outcomes. We performed a retrospective secondary analysis of a prospective cohort of term births (≥ 37 weeks). Fetal anomalies and aneuploidy were excluded. Primary outcome was small for gestational age (SGA). Secondary outcomes included preeclampsia, neonatal cord arterial blood gas pH < 7.10 and < 7.05, base excess < - 8 and < - 12 mEq/L. Outcomes were compared between mothers with low MC airways and high MC airways using logistic regression. A total of 1,823 women met the inclusion criteria. No significant differences were found in the risk of SGA (adjusted odds ratio [aOR] 0.9, 95% confidence interval [CI] 0.6-1.2), preeclampsia (aOR 1.2, 95% CI 0.8-1.9) or neonatal acidemia (aOR 0.8, 95% CI 0.3-2.0), between high and low MC. High MC is not associated with adverse perinatal outcomes.

Monitoring Sound To Quantify Snoring and Sleep Apnea Severity Using a Smartphone: Proof of Concept

Habitual snoring is a prevalent condition that is not only a marker of obstructive sleep apnea (OSA) but can also lead to vascular risk. However, it is not easy to check snoring status at home. We attempted to develop a snoring sound monitor consisting of a smartphone alone, which is aimed to quantify snoring and OSA severity. The subjects included 50 patients who underwent diagnostic polysomnography (PSG), of which the data of 10 patients were used for developing the program and that of 40 patients were used for validating the program. A smartphone was attached to the anterior chest wall over the sternum. It acquired ambient sound from the built-in microphone and analyzed it using a fast Fourier transform on a real-time basis. Snoring time measured by the smartphone highly correlated with snoring time measured by PSG (r = 0.93). The top 1 percentile value of sound pressure level (L1) determined by the smartphone correlated with the ambient sound L1 during sleep determined by PSG (r = 0.92). Moreover, the respiratory disturbance index estimated by the smartphone (smart-RDI) highly correlated with the apnea-hypopnea index (AHI) obtained by PSG (r = 0.94). The diagnostic sensitivity and specificity of the smart-RDI for diagnosing OSA (AHI ≥ 15) were 0.70 and 0.94, respectively. A smartphone can be used for effectively monitoring snoring and OSA in a controlled laboratory setting. Use of this technology in a noisy home environment remains unproven, and further investigation is needed.