Sleep-disordered Breathing Measures Research Articles

Abstract P365: Objectively Measured Snoring is Associated with Carotid Vascular Remodeling in Overweight and Obese Adults

Introduction: Snoring is often used as a surrogate measure for obstructive sleep apnea (OSA), a sleep disorder associated with elevated cardiovascular disease (CVD) risk. Although the literature supports a link between snoring and CVD, it is not clear if this association is independent of OSA. The objective of our study was to explore the association between snoring and subclinical CVD in adults with and without OSA. We hypothesized that snorers would have a greater burden of subclinical CVD, including thicker carotid intima media thickness (CIMT) and higher pulse wave velocity (PWV). Methods: Cross-sectional analyses were conducted using 24-month follow up data from the Slow Adverse Vascular Effects (SAVE) study, a randomized controlled trial evaluating the effects of weight loss, increased physical activity, and reduced dietary sodium intake on vascular health. The original population included 349 men and women aged 20-45 years and BMI 25-40 kg/m 2 . Participants (n=122) with objective measures of sleep-disordered breathing from a home-based sleep assessment (ResMed ApneaLink) were grouped into three categories using the snoring index (SI) and oxygen desaturation index (ODI). SI is defined as the number of vibratory snoring events per hour of recording time . ODI is the number of oxyhemoglobin desaturations of ≥ 4% per hour of recording . The snoring categories were: OSA (ODI≥5; n=41), heavy snoring (ODI<5, above-median SI; n=40), and normal snoring (ODI<5, below-median SI; n=41). Vascular measures such as carotid-femoral PWV (cfPWV), femoral-ankle PWV (faPWV), brachial-ankle PWV (baPWV), CIMT, and carotid inter-adventitial diameter were compared across snoring groups. We used multiple linear regression to assess the association between snoring and subclinical CVD independent of age, sex, BMI, mean arterial pressure, and intervention group. Results: Participants were on average 40.1 ± 5.9 years old (BMI of 31.6 ± 4.4 kg/m 2 ; 76.2% women and 82% white). Across snoring severity categories, most CVD risk factors worsened including age, blood pressure, BMI, lipids, and fasting glucose (ANOVA; all p <.05). Similarly, vascular measures including faPWV, baPWV, CIMT, inter-adventitial diameter and bulb IMT differed across snoring categories with differences occurring mainly between the normal snoring and OSA groups. Differences in carotid inter-adventitial diameter and CIMT were noted between normal and heavy snoring groups (6.52 ± 0.49 vs. 6.83 ± 0.49; 0.58 ± 0.06 vs. 0.63 ± 0.07; mm), respectively. Following covariate adjustment, differences in carotid inter-adventitial diameter and IMT persisted between normal and heavy snoring categories (p <.05). Conclusion: Our findings suggest that, in overweight and obese adults, objectively measured snoring is related to indices of local vascular remodeling and aging, even in those without OSA. Snoring severity may be associated with CVD risk.

The association between different features of sleep-disordered breathing and blood pressure: A cross-sectional study.

Sleep disordered breathing (SDB) is highly prevalent in patients with high blood pressure (BP). Severity of SDB can be evaluated by the number of apneas and hypopneas per hour (AHI) or by measures of hypoxia. The objective of this study was to assess the association between different measures of SDB and BP. In 134 consecutive patients, polygraphy was performed to determine the AHI. Pulse oximetry was used to determine hypoxemic burden (time below 90% oxygen saturation [T90] and hypoxia load [HL], representing the integrated area above the curve of desaturation). AHI did not correlate with systolic and diastolic BP or pulse pressure. In contrast, HL correlated with pulse pressure during the day (P=.01) and night (P=.0034) before and after adjustment for body mass index. The correlation between systolic BP and HL at night disappeared following adjustment for body mass index. This study generates the hypothesis that nocturnal hypoxemic burden may represent a suitable marker of BP pattern and a potential treatment target in hypertensive patients.

Nocturnal hypoxemic burden is associated with epicardial fat volume in patients with acute myocardial infarction.

Increased epicardial fat volume (EFV) is a common feature of patients with sleep-disordered breathing (SDB), is considered as an established marker of cardiovascular risk, and is associated with adverse cardiovascular events after myocardial infarction (MI). To investigate the association between different measures of SDB severity and EFV after acute MI, we enrolled 105 patients with acute MI in this study. Unattended in-hospital polysomnography was performed to determine the number of apneas and hypopneas per hour during sleep (apnea-hypopnea index, AHI). To determine nocturnal hypoxemic burden, we used pulse oximetry and applied a novel parameter, the hypoxia load representing the integrated area of desaturation divided by total sleep time (HLTST). Of 105 patients, 56 underwent cardiovascular magnetic resonance to define EFV. HLTST was significantly associated with EFV (r2 = 0.316, p = 0.025). Multivariate linear regression analysis accounting for age, sex, body mass index, smoking, and left ventricular mass demonstrated that the HLTST was an independent modulator of EFV (B-coefficient 0.435 (95% CI 0.021-0.591); p = 0.015). In contrast, AHI or established measures of hypoxemia did not correlate with EFV. HLTST, a novel parameter to determine nocturnal hypoxemic burden, and not AHI as an event-based measure of SDB, was associated with EFV in patients with acute MI. Further studies are warranted to confirm the link between nocturnal hypoxemia and EFV and to determine the prognostic value of a more detailed characterization of nocturnal hypoxemic burden in patients with high cardiovascular risk.

0431 PATHOPHYSIOLOGIC ASPECTS OF SLEEP DISORDERED BREATHING AND PAROXYSMAL ATRIAL FIBRILLATION

Although associations of sleep disordered breathing (SDB) and continuous atrial fibrillation (AF) have been well-characterized, the relationship of SDB and paroxysmal AF (PAF), an earlier stage in the AF evolution, is not well understood. We sought to examine the association of SDB and its attendant pathophysiologic attributes in relation to PAF. We leverage a case control study designed to examine the underlying mechanisms of SDB and PAF: the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiological Atrial Triggers (SAFEBEAT, NCT02576587). Cases were >18 years with PAF1:1 matched to controls without AF by age (±5 years), sex, race and body mass index (BMI±5kg/m2) who underwent 16-channel research-grade polysomnography. SDB was defined by apnea hypopnea (>3% desaturation) index (AHI), central apnea index (CAI), percentage sleep time <90% oxygen saturation (TST<90) and arousal index (AI). Conditional logistic regression models were used to assess relationships of SDB measures and PAF. Multivariable models were further adjusted for hypertension, diabetes, myocardial infarction history, dyslipidemia and depression (odds ratio and 95% confidence intervals presented). The analytic sample was comprised of 300 participants (n=150 cases, n=150 controls): age 61.9 ± 11.9 years, 63.3% male, and BMI 31.4 ± 6.7kg/m2. Unadjusted analyses demonstrate a statistically significant inverse association of AHI and PAF (OR=0.95, 95%CI: 0.93–0.97) which persisted in the multivariable model (OR=0.95, 95%CI: 0.93–0.98). High blood pressure had a significant association with PAF (OR= 1.97, 95%CI: 1.013–3.82). No significant associations were observed for CAI, AI and TST<90 relative to PAF. The current findings demonstrate a 5% decreased odds of PAF per single unit increase in AHI consistent with an unanticipated inverse association. Given existing data showing increased risk of mainly continuous AF in SDB, it is possible that SDB may exert variable influences (beneficial versus detrimental) depending upon the extent of cardiac remodeling and stage of AF evolution. NHLBI RO1 1 R01 HL 109493, Clinical and Translational Science Collaborative of Cleveland,UL1TR000439 from the National Center for Advancing Translational Sciences (NCATS) component of the National Institutes of Health and NIH roadmap for Medical Research.

Association between Sleep Disordered Breathing and Nighttime Driving Performance in Mild Cognitive Impairment.

The effect of sleep disordered breathing (SDB) on driving performance in older adults has not been extensively investigated, especially in those with mild cognitive impairment (MCI). The aim of this study was to examine the relationship between severity measures of SDB and a simulated driving task in older adults with and without MCI. Nineteen older adults (age ≥50) meeting criteria for MCI and 23 age-matched cognitively intact controls underwent neuropsychological assessment and a driving simulator task in the evening before a diagnostic sleep study. There were no differences in driving simulator performance or SDB severity between the two groups. In patients with MCI, a higher oxygen desaturation index (ODI) was associated with an increased number of crashes on the simulator task, as well as other driving parameters such as steering and speed deviation. Poorer driving performance was also associated with poorer executive functioning (set-shifting) but the relationship between ODI and crashes was independent of executive ability. While driving ability did not differ between older adults with and without MCI, oxygen saturation dips in MCI were related to worse driving performance. These results suggest that decreased brain integrity may render those with SDB particularly vulnerable to driving accidents. In older adults, both cognition and SDB need to be considered concurrently in relation to driving ability. (JINS, 2017, 23, 502-510).

Association between sleep disordered breathing and electrocardiographic markers of atrial abnormalities: the MESA study.

Electrocardiographic (ECG) markers of left atrial (LA) abnormalities have been linked to increased risk of atrial fibrillation (AF). Sleep disordered breathing (SDB) has been associated with increased risk of AF. We aimed to examine the association of ECG markers of LA abnormalities with SDB. 1546 participants (mean age 67.2 years, 53.4% women, and 63.3% non-whites) from the Multi-Ethnic Study of Atherosclerosis Exam 5 Sleep ancillary study were included in this analysis. ECG markers of LA abnormalities (P wave terminal force in V1 (PTFV1), maximum P wave duration, PR interval and heart rate corrected PR interval) were measured from resting standard digital ECG tracings using standardized processing. Linear and logistic regression analyses were utilized to examine the cross-sectional associations of measures of SDB (apnea hypopnea index [AHI] and % time spent with oxygen saturation <90% [%SpO290]) with each ECG marker. In a multivariable analysis adjusting for demographics, cardiovascular risk factors, and comorbidities, AHI was associated with greater PTFV1 but not with other ECG markers of LA abnormalities. A 1-SD increase of AHI (16.6/hr) was associated with higher levels of PTFV1 (175.1 µV.ms, 95% confidence interval [95%CI] 75.4, 274.7) and higher odds of abnormally elevated PTFV1 (≥4000 µV.ms) (Odds Ratio: 1.21 [95%CI 1.05, 1.39]). No association was found between %SpO290 and ECG markers of LA abnormalities. Severity of SDB, as measured by AHI, is associated with subclinical LA disease, as indicated by PTFV1. PTFV1 may be an important ECG marker linking SDB and AF.

Polysomnographic Heart Rate Variability Indices and Atrial Ectopy Associated with Incident Atrial Fibrillation Risk in Older Community-dwelling Men.

Autonomic dysfunction contributes to atrial fibrillation (AF). We hypothesized that polysomnogram (PSG)-based heart rate variability (HRV) autonomic function biomarkers are associated with incident AF and these associations are modified by measures of sleep disordered breathing (SDB). 2350 participants of a multi-center prospective study (Outcomes of Sleep Disorders in Older Men Study) without baseline AF underwent sleep studies with incident adjudicated AF follow up (8.0 ± 2.6 years). Cox proportional hazard models were used to analyze sleep study-ECG spectral HRV indices [low and high frequency power (LF, HF), LF/HF] and time domain indices [mean of normal to normal beats (MNN), short and long term variability (STV, LTV) and STV/LTV] and premature atrial contractions (PACs) and incident AF (HR and 95% CI). Statistical interactions between HRV and SDB were examined. Models were adjusted for age, race, body mass index, waist circumference, cardiac medications, co-morbid diseases, alcohol use and study site. Lower LF/HF and lower LF were associated with higher AF incidence (LF/HF Q1 vs. Q4: 1.46, 1.02-2.08, LF Q1 vs. Q4: 1.46, 1.02-2.10). Higher STV/LTV was associated with an increased risk of AF (p-trend= 0.028). The highest PAC quartile had a 3-fold increased AF risk (2.99, 1.94-4.62) compared to the lowest quartile. A significant interaction of obstructive apnea was observed in the LF-AF relationship (0.045). Sleep-related reduced sympathovagal balance (LF/HF) and increased atrial ectopy are independently associated with future AF; a relationship modified by obstructive apnea.

Sleep Disordered Breathing and White Matter Hyperintensities in Community-Dwelling Elders.

To examine the association between markers of sleep-disordered breathing (SDB) and white matter hyperintensity (WMH) volume in an elderly, multiethnic, community-dwelling cohort. This is a cross-sectional analysis from the Washington Heights-Inwood Columbia Aging Project (WHICAP), a community-based epidemiological study of older adults. Structural magnetic resonance imaging was obtained starting in 2004; the Medical Outcomes Study-Sleep Scale (MOS-SS) was administered to participants starting in 2007. Linear regression models were used to assess the relationship between the two MOS-SS questions that measure respiratory dysfunction during sleep and quantified WMH volume among WHICAP participants with brain imaging. A total of 483 older adults had both structural magnetic resonance imaging and sleep assessment. Self-reported SDB was associated with WMH. After adjusting for demographic and vascular risk factors, WMH volumes were larger in individuals with frequent snoring (β = 2.113, P = 0.004) and among those who reported waking short of breath or with headache (β = 1.862, P = 0.048). In community-dwelling older adults, self-reported measures of SDB are associated with larger WMH volumes. The cognitive effects of SDB that are increasingly being recognized may be mediated at the small vessel level.

Sleep-disordered breathing and daytime cardiac conduction abnormalities on 12-lead electrocardiogram in community-dwelling older men.

Nocturnal cardiac conduction abnormalities are commonly observed in patients with sleep-disordered breathing (SDB). However, few population-based studies have examined the association between SDB and daytime cardiac conduction abnormalities. We examined a random sample of 471 community-dwelling men, aged ≥67years, enrolled in the multi-center Outcomes of Sleep Disorders in Older Men (MrOS Sleep) study. SDB severity was categorized using percent of total sleep time with oxygen saturation <90% (%TST < 90) and apnea hypopnea index (AHI). Cardiac conduction parameters were assessed by resting 12-lead electrocardiography (ECG). All analyses were adjusted for age, site, β-blocker use, coronary heart disease, calcium channel blocker use, and use of antiarrhythmic medications. Mean age was 77 ± 6years, median %TST < 90 was 0.7 (IQR 0.00-3.40), and median AHI was 7.06 (IQR 2.55-15.32). Men with greater nocturnal hypoxemia (%TST < 90 ≥ 3.5%) compared with those without hypoxemia (%TST < 90 < 1.0%) had a lower odds of bradycardia (OR 0.55 [0.32-0.94]) and right bundle branch block (RBBB) (OR 0.24 [0.08-0.75]) but a higher odds of ventricular paced rhythm (OR 4.42 [1.29-15.19]). Heart rate (HR) increased in a graded manner with increasing %TST < 90 (p-trend 0.01) and increasing AHI (p-trend 0.006), but these gradients were small in absolute magnitude. There were no associations of SDB measures with other ECG conduction parameters. Greater nocturnal hypoxemia in older men was associated with a lower prevalence of daytime sinus bradycardia and RBBB, a higher prevalence of ventricular paced rhythm, and higher resting HR.

Study of sleep related respiratory disorders in patients with idiopathic pulmonary arterial hypertension

The effects of sleep-disordered breathing (SDB) and nocturnal hypoxemia on pulmonary hemodynamics have long interested physicians who manage patients with pulmonary arterial hypertension. The aim of the present study is to study the prevalence and identify the types of sleep related breathing disorders in patients with IPAH in the state of Kuwait. Patients and methods36 patients(32 females and 4 males) were included, the mean age was 35.2±17.3years, all patients were non-smokers and non-obese. All patients were subjected to routine investigations, Echocardiography, CT pulmonary angiography and full night polysomnography. All cases pulmonary hypertension related to cardiac disease or collagenic vascular disease or Thromboembolic disease were excluded. ResultsThe mean AHI was 13.8±8.3/h of sleep with OSA proved in 5 patients (13.9%) and CSR/CSA proved in 2 patients (5.56%). Nocturnal desaturation was more pronounced in the studied patient as 27 patients (75%) showed nocturnal desaturation. There was a significant correlation between SDB measures and baseline oxygen saturation, lowest oxygen saturation during walking and mean PAP. ConclusionSDB is significant in patients with IPAH and can affect the disease progression and the quality of life of those patients. All patients should undergo sleep study to identify patients who are in need of nocturnal oxygen therapy or in need for CPAP therapy in case of OSA.

Abstract 18672: Association Between Sleep Disordered Breathing and Electrocardiographic Markers of Atrial Abnormalities: The MESA Study

Introduction: Abnormal P wave terminal force in V1 (PTFV1), an electrocardiographic marker of left atrial abnormalities, has been linked to increased risk of atrial fibrillation (AF). Examining the association between sleep disordered breathing (SDB) and PTFV1 might shed light on the potential mechanisms by which SDB increases risk of AF. Methods: A total of 1546 participants (mean age 67.2 (± 8.8) years, 53.4 % women and 63.3 % non-Whites) from the Multi-Ethnic Study of Atherosclerosis (MESA) Exam 5 Sleep ancillary were included in this analysis. PTFV1 was measured from resting standard digital ECG tracings that were automatically processed centrally. Linear and logistic regression analyses were used to examine the cross-sectional associations between measures of SDB (apnea hypopnea index [AHI], obstructive AHI [OAHI] and % time spent with oxygen saturation &lt;90% [% SpO2 90]) and PTFV1. Results: There was a trend of higher PFTV1 values across quartiles of AHI, OAHI and % SpO2 90 (p for trend &lt;0.01 for each). In multivariable linear regression models, the upper quartile of AHI and OAHI measures were associated with higher values of PTFV1 compared with the lower quartile (Table). A 1-SD increase of AHI and OAHI were associated with increased levels of PTFV1 (Table). When PTFV1 was considered as a binary variable (using the cut point of 4000 μV.ms to define abnormality) in logistic regression analysis, AHI and OAHI were also associated with abnormal PTFV1. Conclusion: Severity of SDB, as measured by AHI is associated with subclinical left atrial disease, as measured by PTFV1. This could partially explain the reported association between SDB and AF.

Association between Sleep-Disordered Breathing and Neuropsychological Performance in Older Adults with Mild Cognitive Impairment.

Sleep-disordered breathing in middle-age and older adults has been shown to be linked to a range of neuropsychological deficits, but the extent to which these relationships are evident in older people 'at risk' of developing dementia in unknown. In this study, we aimed to determine whether changes in sleep-disordered breathing and sleep fragmentation during nocturnal sleep were related to neuropsychological dysfunction in patients with mild cognitive impairment. Forty-six patients with MCI (mean age = 66.1 y, sd = 8.4) and 40 age-matched healthy controls (mean age = 63.5 y, sd = 8.9) underwent psychiatric, medical, and neuropsychological assessment, in addition to overnight polysomnography and self-report questionnaires. Measures of hypoxemia, sleep fragmentation, and sleep quality were derived including the apnoea-hypopnea index, oxygen desaturation index, percentage of total sleep time spent below 90% oxygen saturation, arousal index, sleep efficiency, and wake after sleep onset. Patients with MCI did not differ from healthy aging on any measure of sleep-disordered breathing or sleep fragmentation. In MCI, processing speed was negatively correlated with greater sleep time spent below 90% oxygen saturation and a higher apnoea-hypopnea index. In contrast, in the healthy aging, processing speed was negatively correlated with an increased oxygen desaturation index and the arousal index. Sleep-disordered breathing is evident in both healthy aging and MCI with associated decrements in processing speed. Future research is needed to determine the unique and synergistic effects of these differential associations, their potential to inform disease trajectory, and possible therapeutic interventions.

Predicting poor school performance in children suspected for sleep-disordered breathing

ObjectiveHabitually snoring children are at a greater risk of poor school performance (PSP). We investigated the ability of conventional sleep-disordered breathing (SDB) measures for predicting PSP in habitually snoring children. MethodsThe dataset of Hannover Study on Sleep Apnea in Childhood (HASSAC), a large community-based study in primary school children, was retrospectively analyzed. All habitual snorers were included. Based on their grades, children were grouped into good and poor school performers. SDB measures obtained by a parental questionnaire, a home pulse oximetry, and a home polysomnography were evaluated for their accuracy in predicting poor school performance by calculating receiver operating characteristic curves and area under this curve (AUC). The most predictive single factors were identified and entered into a prediction model. ResultsOf 114 habitual snorers (mean age 9.6 years, 51 boys), 59 had PSP. All investigated SDB measures showed low accuracy (ie, AUC <0.8). The highest AUC observed was 0.686 for a questionnaire score, 0.565 for an oximetry factor, and 0.624 for a polysomnography factor. Of 20 single significant predictors for PSP, five were selected for inclusion into a prediction model. The model reached an unadjusted AUC of 0.826 and an adjusted AUC of 0.851. ConclusionsConventional SDB measures obtained with questionnaire, oximetry, or polysomnography may not be sufficiently predictive of PSP in children suspected for SDB. However, combining factors in a clinical prediction model may improve prediction. Results of such a model may be used to assess the risk of developing neurocognitive impairment and to decide whether a child suspected for SDB might benefit from treatment.

Growth Hormone Therapy in Adults with Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is characterized by hyperphagia, obesity if food intake is not strictly controlled, abnormal body composition with decreased lean body mass and increased fat mass, decreased basal metabolic rate, short stature, low muscle tone, cognitive disability, and hypogonadism. In addition to improvements in linear growth, the benefits of growth hormone therapy on body composition and motor function in children with PWS are well established. Evidence is now emerging on the benefits of growth hormone therapy in adults with PWS. This review summarizes the current literature on growth hormone status and the use of growth hormone therapy in adults with PWS. The benefits of growth hormone therapy on body composition, muscle strength, exercise capacity, certain measures of sleep-disordered breathing, metabolic parameters, quality of life, and cognition are covered in detail along with potential adverse effects and guidelines for initiating and monitoring therapy.

Abstract 11556: Association of Sleep Disordered Breathing and ECG R-Wave to Radial Artery Pulse Delay: The MESA Study

Background: Arterial stiffness is a well-recognized predictor of cardiovascular disease (CVD). ECG R-wave to Radial artery pulse delay (RRD) is a novel hemodynamic index in which arterial stiffness is an important component (shorter delay = Higher arterial stiffness) and is obtainable from a single tonometric measurement at the radial artery with simultaneous ECG. Sleep disordered breathing (SDB) has emerged as a risk factor for CVD. The aim of the study was to determine the association of SDB with RRD. Methods: Multi-Ethnic Study of Atherosclerosis participants in 2010-2012 without overt CVD who underwent a sleep study, radial artery tonometry and cardiac MRI were eligible for this cross-sectional analysis (N = 1173, Mean [SD] age: 67.8 ± 8.8, Women: 55.4%). Independent associations between SDB indices including apnea hypopnea index (AHI) and oxygen (O2) desaturation index (ODI: events with more than 4% O2 desaturation), and RRD (transit time in msec) were examined. Model was constructed to adjust for isovolumetric contraction time, another component of RRD, by including measures of contractility and preload (left ventricular ejection fraction (LVEF) and left ventricular end diastolic volume (LVEDV) respectively). Results: Median [IQR] of AHI and ODI were 7.9/hr [2.9- 18.0] and 7.5/hr [3.0- 17.5] respectively. Adjusting for transit path length, demographic factors, BMI and CVD risk factors, both AHI and ODI were inversely associated with RRD (β= -50.3 msec per SD, p = 0.09 and β= -0.60.2 msec per SD, p = 0.04 respectively). In gender stratified analyses given presence of significant interaction, measures of SDB were predictive of RRD only in men. No significant associations were found with key nocturnal hypoxemia indices including mean O2 saturation (SpO2), percent time with SpO2less than 90 % and minimum SpO2. Men, older age, Asian race, high blood pressure, LVEF and LVEDV were also inversely associated with RRD. Conclusion: SDB was associated with shorter RRD implying higher arterial stiffness in men only. These findings suggest the importance of apnea related dynamic change in SpO2 (intermittent hypoxia and reoxygenation) in its potential link to arterial stiffness and also highlights effect modification by gender in the association between the two.

Nocturnal blood pressure non‐dipping is prevalent in severely obese, prepubertal and early pubertal children

To investigate the prevalence of nocturnal blood pressure dipping among obese prepubertal and early pubertal children and to analyse the relationship between dipping and measures of insulin-glucose metabolism or sleep-disordered breathing. We studied 76 obese children (41% girls) under clinical care, with an average age of 10.4 ± 1.7 and a body mass index Z-score (BMI Z-score) of 6.2 ± 1.6. We performed a 24-h ambulatory blood pressure measurement. Non-dipping was defined as a nocturnal blood pressure reduction of <10%. We calculated measures of insulin-glucose metabolism from the performed frequently sampled intravenous glucose-tolerance test and from fasting blood samples. Overnight sleep polygraph recordings were performed to assess sleep-disordered breathing. Forty-two percent of the children were systolic non-dippers, and 17% were diastolic non-dippers. There were no associations between systolic or diastolic dipping and measures of insulin-glucose metabolism after adjustments for BMI Z-score, gender and pubertal status. There were no associations between dipping and measures of sleep-disordered breathing. Nocturnal non-dipping was two times higher among severely obese, prepubertal and early pubertal children, compared to previous reports among children in general. There were no associations between nocturnal dipping and insulin-glucose metabolism or measures of sleep-disordered breathing in this group.

Snoring, mouth-breathing, and apnea trajectories in a population-based cohort followed from infancy to 81 months: A cluster analysis

Objective The objective of this study was to characterize phenotypes of sleep disordered breathing (SDB) in early childhood that clinicians may find useful while monitoring symptom progression and associated SDB morbidity. Methods We performed a cluster analysis of SDB's primary symptoms: snoring, mouth-breathing, and apnea. Parents in the Avon Longitudinal Study of Parents and Children (ALSPAC) reported SDB symptoms by questionnaire for their child at 6, 18, 30, 42, 57, 69, and 81 months of age. Participants were those from the original cohort exclusive of children with congental or other medical conditions predisposing growth aberrations or respiratory problems (i.e. cleft palate, heart surgery and associated conditions, genetic syndromes—primarily Down's, cancer or kidney conditions, celiac disease, congenital adrenal hyperplasia), missing SDB measures for ≥2 timepoints, or missing birth length plus 2 subsequent height measures. Results Five clusters emerged from 10,441 children and were characterized according to patterns of mean severity of SDB symptoms over time. “Normals” (50%) were asymptomatic throughout. The “late snores and mouth-breathing” cluster (20%) remained asymptomatic until 4 years old. The “early snores” (10%) and “early apnea” (10%) clusters had peak symptoms at 6 and 18 months, respectively. In “all SDB after infancy” (10%), symptoms peaked from 30 to 42 months and remained elevated. Exploratory analyses found that “early snores” were significantly shorter than “normals.” Associations with tonsillectomies and wheezing frequency supported external validation. Conclusions Cluster analysis has elucidated the dynamic multi-symptom expression of SDB. The utility of cluster analysis will be evaluated in future analyses to predict growth, cognition and behavior outcomes.

Predictors of Response to a Nasal Expiratory Resistor Device and Its Potential Mechanisms of Action for Treatment of Obstructive Sleep Apnea

A one-way nasal resistor has recently been shown to reduce sleep disordered breathing (SDB) in a subset of patients with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS). The purpose of this study was to examine characteristics predictive of therapeutic response to the device and provide pilot data as to its potential mechanisms of action. PATIENTS, INTERVENTIONS, AND MEASUREMENTS: 20 subjects (15M/5F, age 54 ± 12 years, BMI 33.5 ± 5.6 kg/m²) with OSAHS underwent 3 nocturnal polysomnograms (NPSG) including diagnostic, therapeutic (with a Provent® nasal valve device), and CPAP. Additional measurements included intranasal pressures and PCO₂, closing pressures (Pcrit), and awake lung volumes in different body positions. In 19/20 patients who slept with the device, RDI was significantly reduced with the nasal valve device compared to the diagnostic NPSG (27 ± 29/h vs 49 ± 28/h), with 50% of patients having an acceptable therapeutic response. Among demographic, lung volume, or diagnostic NPSG measures or markers of collapsibility, no significant predictors of therapeutic response were found. There was a suggestion that patients with position-dependent SDB (supine RDI > lateral RDI) were more likely to have an acceptable therapeutic response to the device. Successful elimination of SDB was associated with generation and maintenance of an elevated end expiratory pressure. No single definitive mechanism of action was elucidated. The present study shows that the nasal valve device can alter SDB across the full spectrum of SDB severity. There was a suggestion that subjects with positional or milder SDB in the lateral position were those most likely to respond.

Characterization of sleep disturbance in Cornelia de Lange Syndrome

Objective Prior studies have suggested that sleep disturbance is common in Cornelia de Lange Syndrome (CdLS); however, the nature of this sleep disturbance has not been well characterized. In this study, we evaluate the prevalence of sleep disordered breathing (SDB) and sleepiness in children and young adults with CdLS. Methods Caregivers of 22 patients with CdLS completed 3 validated Pediatric Sleep Questionnaires: the Pediatric Sleep Questionnaire (PSQ), Pediatric Daytime Sleepiness Scale (PDSS), and OSA18. Results Both measures of SDB (OSA18 and PSQ) suggest that 35–36% of these patients may have moderate to severe SDB. This is much higher than the general population estimates of 1–4% for SDB with a relative risk of 5.2 (95% CI: 2.8–9.9). Correlation between the OSA18 and PSQ was significant ( R = 0.67; 95% CI: 0.33–0.85, p = 0.0007). Confirming these results among patients with a high probability of SDB (based upon OSA18 scores ≥60), there was a non-significant trend toward increased sleepiness with a relative risk of 2.0 (95% CI: 0.73–5.7, p = 0.31) on the PDSS and 2.9 (95% CI: 0.93–9.1, p = 0.08) on the PSQ sleepiness scale. In those patients with low probability of SDB (OSA18 < 60), sleepiness was still seen in 13–29% of patients. Overall 23–35% of participants were characterized as sleepy. Conclusions Sleep disordered breathing and sleepiness appear to be common in CdLS although small sample sizes limit further conclusions. Additional studies with larger sample size and confirmation with polysomnography are needed to further explore the nature and extent of sleep disturbance in this population.

Do Weather-Related Ambient Atmospheric-Pressure Changes Influence Sleep Disordered Breathing?

High-altitude studies of sleep disordered breathing (SDB) show increases in apnea hypopnea indices with elevation gains. Hypoxic changes, rather than reductions in atmospheric pressure (AP), are thought to be the driving factor. Ambient pressure-related changes in SDB have not been extensively studied at low altitude. We performed a cross-sectional study of weather-related AP effects on measures of SDB at the University of WashingtonMedicine Sleep Institute, a Seattle, Washington-based polysomnography lab located 200 feet above sea level. Obstructive, central, and apnea-hypopnea indices from 537 patients were retrospectively correlated to mean 8-hour date-matched overnight AP data. Linear regression analysis and interquartile comparison of AP-related respiratory indices were performed and adjusted for age, sex, and body mass index. The obstructive apnea index increased with lower weather-related APs (p = 0.01 for linear trend), interquartile analysis showed significant worsening with lowered mean, minimum, and maximum nightly APs. Similar changes were not seen with central or apnea-hypopnea indices. The obstructive apnea index is altered by changes in weather-related AP during diagnostic polysomnography performed at 200 feet above sea level. Small changes in ambient atmospheric pressure due to weather systems may be important in the pathophysiology and diagnosis of obstructive sleep apnea.