Relation of sleep-disordered breathing to cardiovascular disease risk factors: the Sleep Heart Health Study

Biomarkers and Dynamic Cerebral Autoregulation of Obstructive Sleep Apnea-Hypopnea Syndrome

OBJECTIVE

Patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) have impaired dynamic cerebral autoregulation (dCA). This study aimed to explore whether serum levels of apolipoprotein B-100 (ApoB-100), fibronectin (FN), and ceruloplasmin (CP) were related to impaired dCA in OSAHS.

METHODS

A total of 90 patients with OSAHS from our database management system were enrolled and further divided into three subgroups according to the apnea-hypopnea index (AHI) using polysomnography results: mild (5 ≤ AHI ≤ 15), moderate (15 < AHI ≤ 30), and severe OSAHS (AHI > 30), with 30 patients in each group. Thirty sex- and age-matched healthy controls were recruited for this study. The serum levels of ApoB-100, FN, and CP were measured by enzyme-linked immunosorbent assays. dCA was assessed by analyzing the phase difference (PD) using transfer function analysis.

RESULTS

Serum levels of ApoB-100, FN, and CP were significantly higher in the mild, moderate, and severe OSAHS groups than that in the control group (P<0.001, respectively). The average PD of the moderate and severe OSAHS groups was lower than that of the control group (P=0.001 and P<0.001, respectively). Receiver operating curve analysis revealed that ApoB-100, FN, and CP might be able to distinguish patients with OSAHS from healthy individuals (area under the curve = 0.959 [95% CI 0.92-1.00], 0.987 [95% CI 0.96-1.01], 0.982 [95% CI 0.96-1.00]), respectively, P<0.001). The average PD was linearly correlated with the serum levels of ApoB-100, FN, and CP in patients with OSAHS. Multivariable analysis showed that FN and arousal index in polysomnography were associated with impaired average PD (P<0.001 and P=0.025, respectively).

CONCLUSION

Serum levels of ApoB-100, FN, and CP increased in patients with OSAHS. dCA was compromised in patients with OSAHS and was positively correlated with ApoB-100, FN, and CP serum levels, and FN serum levels and arousal index in polysomnography were independently associated with impaired dCA.

Diabetes and respiratory system including tuberculosis - challenges

Diabetes mellitus is a common disorder associated with systemic inflammation and oxidative stress affecting various organ systems leading to microvascular (retinopathy, nephropathy and neuropathy) and macrovascular (myocardial infarction, stroke, peripheral vascular disease) complications. Although the impact of diabetes on lung functions has been previously reported, especially in asthma and COPD, the lung has not been described as a common target organ in diabetes and this has important medical, social and financial consequences in our already overburdened healthcare system. The underlying mechanism and pathophysiology of such an association have rarely been described in the literature. This review aims to discuss the effects of diabetes on lungs, probable mechanisms by which hyperglycemia may affect lung functions and mechanisms by which respiratory diseases can lead to onset, or worsening of pre-existing hyperglycemia with inherited challenges in the management.

Sleep heart rate variability assists the automatic prediction of long-term cardiovascular outcomes

OBJECTIVE

We aimed to investigate the association between sleep HRV and long-term cardiovascular disease (CVD) outcomes, and further explore whether HRV features can assist the automatic CVD prediction.

METHODS

We retrospectively analyzed polysomnography (PSG) data obtained from 2111 participants in the Sleep Heart Health Study, who were followed up for a median of 11.8 years after PSG acquisition. During follow-up, 1252 participants suffered CVD events (CVD group) and 859 participants remained CVD-free (non-CVD group). HRV measures, derived from time-domain and frequency-domain, were calculated. Regression models were created to determine the independent predictor for long-term CVD outcomes, and to explore the association between HRV and CVD latency. Furthermore, based on HRV and other clinical features, a model was trained to automatically predict CVD outcomes using the eXtreme Gradient Boosting algorithm.

RESULTS

Compared with the non-CVD group, decreased HRV during sleep was found in the CVD group. HRV, particularly its component of high frequency (HF), was demonstrated to be independent predictor of CVD outcomes. Moreover, normalized HF was positively correlated with CVD latency. The proposed prediction model achieved a total accuracy of 75.3%, in which sleep HRV features served as a supplement to the well-recognized CVD risk factors, such as aging, adiposity and sleep disorders.

CONCLUSIONS

Association between sleep HRV and long-term CVD outcomes was demonstrated here, suggesting that altered HRV during sleep might occur many years prior to the onset of CVD. Machine learning models, combining sleep HRV and other clinical characteristics, should be promising in the early prediction of CVD outcomes.

Obstructive sleep apnea and dyslipidemia: from animal models to clinical evidence

Lipid metabolism deregulation constitutes the pathogenic basis for the development of atherosclerosis and justifies a high incidence of cardiovascular-related morbidity and mortality. Some data suggest that dyslipidemia may be associated with sleep-disordered breathing, mainly obstructive sleep apnea (OSA), due to alterations in fundamental biochemical processes, such as intermittent hypoxia (IH). The aim of this systematic review was to identify and critically evaluate the current evidence supporting the existence of a possible relationship between OSA and alterations in lipid metabolism. Much evidence shows that, during the fasting state, OSA and IH increase lipid delivery from the adipose tissue to the liver through an up-regulation of the sterol regulatory element-binding protein-1 and stearoyl-CoA desaturase-1, increasing the synthesis of cholesterol esters and triglycerides. In the postprandial state, lipoprotein clearance is delayed due to lower lipoprotein lipase activity, probably secondary to IH-up-regulation of angiopoietin-like protein 4 and decreased activity of the peroxisome proliferator-activated receptor alpha. Moreover, oxidative stress can generate dysfunctional oxidized lipids and reduce the capacity of high-density lipoproteins (HDL) to prevent low-density lipoprotein (LDL) oxidation. In the clinical field, several observational studies and a meta-regression analysis support the existence of a link between OSA and dyslipidemia. Although there is evidence of improved lipid profile after apnea-hypopnea suppression with continuous positive airway pressure (CPAP), the majority of the data come from observational studies. In contrast, randomized controlled trials evaluating the effects of CPAP on lipid metabolism present inconclusive results and two meta-analyses provide contradictory evidence.

Independent association of severity of obstructive sleep apnea with lipid metabolism of atherogenic index of plasma (AIP) and apoB/apoAI ratio

BACKGROUND

Cardiovascular diseases (CVDs) are highly prevalent in obstructive sleep apnea (OSA), and dyslipidemia is an important factor. Atherogenic index of plasma (AIP, log[TG/HDL-C]) and apolipoproteinB to apolipoproteinAI ratio (apoB/apoAI ratio) are considered high quality predictors of cardiovascular risk. However, the associations between OSA severity and AIP and apoB/apoAI ratio remained unclear.

METHODS

A retrospective study was performed in 284 patients. Subjects were assessed with polysomnography (PSG) test, and OSA severity was defined by AHI. Data collected included anthropometric measurements, medical history, sleep parameters, fasting plasma lipids, fasting blood glucose, and insulin.

RESULTS

Participants were classified based on AHI into the following groups: control group (n = 28), mild group (n = 52), moderate group (n = 53), and severe group (n = 151). Triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), apoAI, AIP, apoB/apoAI ratio (low-density lipoprotein cholesterol), LDL-C/HDL-C ratio, and HDL-C/apoAI ratio showed statistical significance among AHI subgroups (P < 0.05). The Pearson correlation analysis revealed that AIP (r = 0.32, P < 0.001) and apoB/apoAI ratio (r = 0.24, P < 0.001) were positively related to AHI. By multivariate linear regression analysis, we found that AHI was independently related to AIP (β = 0.24, P = 0.001), apoB/apoAI ratio (β = 0.24, P<0.001).

CONCLUSION

AHI was independently correlated with AIP and apoB/apoAI ratio in OSA. Our findings suggested that AIP and apoB/apoAI ratio increased with OSA severity, which might be partly responsible for the high risk of CVDs in OSA.

Interrelationships among common predictors of cardiovascular diseases in patients of OSA: A large-scale observational study

BACKGROUND AND AIMS

The apolipoprotein B/apolipoprotein A-I (ApoB/ApoA-I) and insulin resistance has been recognized as common cardiovascular diseases (CVD) risk factors. However, whether they were biomarkers for 10-year CVD risk in obstructive sleep apnea (OSA) had been rarely studied. Besides, interrelationships between the ApoB/ApoA-I, insulin resistance and OSA remain unclear.

METHODS AND RESULTS

A total of 4010 subjects were finally included. Anthropometric, fasting biochemical, and polysomnographic parameters were collected. 10-year Framingham CVD risk score (FRS) was calculated for each subjects. The relationships between insulin resistance, OSA risk and the ApoB/ApoA-I was evaluated through logistic regressions analysis, restricted cubic spline (RCS) analysis and mediation analysis. ApoB/ApoA-I, HOMA-IR and AHI were all risk factors for high10-year CVD risk as assessed by FRS (odds ratios (OR) = 5.365, 1.094, 1.010, respectively, all P < 0.001)). The fully adjusted OR (95% confidence intervals) for both OSA [1 (reference), 1.308 (1.027-1.665), 1.517 (1.178-1.953), and 1.803 (1.371-2.372)] and insulin resistance [1 (reference), 1.457 (1.173-1.711), 1.701 (1.369-2.113), 2.051(1.645-2.558)] increased from the first to the fourth quartiles of the ApoB/ApoA-I. The RCS mapped a nonlinear dose-effect relationship between the ApoB/ApoA-I and risk of insulin resistance and OSA. Mediation analyses showed HOMA-IR explain 9.7%, 4.7% and 10.8% of the association between apnea-hypopnea index, oxygen desaturation index, micro-arousal index and ApoB/ApoA-I, respectively.

CONCLUSIONS

Our study revealed that ApoB/ApoA-I, insulin resistance and OSA were risk factors for CVD. Insulin resistance may serve as a potential mediator in OSA-related lipoprotein disorders and further increase CVD risk.

Are there gender differences in the severity and consequences of sleep disordered in children?

OBJECTIVES

In adults there is a distinct gender difference in the prevalence and severity of sleep disordered breathing (SDB), however there have been limited studies examining the effects of gender in children with SDB. We aimed to compare the effects of gender on severity of SDB, blood pressure, sleep and respiratory characteristics, quality of life, behavior and executive function.

METHODS

We included 533 children aged 3-18 years, who underwent standard pediatric overnight polysomnography (PSG) between 2004 and 2016. Blood pressure was recorded prior to each study. Quality of life, behavior and executive function were assessed with parental questionnaires. Children were grouped by gender and SDB severity based on their obstructive apnea hypopnea index (OAHI) into non-snoring controls, Primary Snoring (PS) (OAHI≤1 event/h), Mild obstructive sleep apnea (OSA) (OAHI>1-≤5 events/h) and moderate/severe (MS) OSA (OAHI>5 events/h) and data compared with 2-way ANOVA.

RESULTS

A total of 298 boys and 235 girls were studied. There were no differences in age, BMI z-score, SDB severity sleep characteristics or blood pressure between genders. Diastolic blood pressure was elevated in females with MS OSA compared to males (P < 0.05). Quality of life, behavior and executive function scores were all elevated in the SDB groups compared to controls. Females with MS OSA exhibited more internalizing behavioral problems compared to males (59.2 ± 2.4 vs. 51.4 ± 2.3, P < 0.05).

CONCLUSIONS

In contrast to studies in adults, we identified no gender differences in the severity or consequences of SDB in children, other than females with moderate-severe OSA exhibiting more internalizing problems and higher diastolic blood pressure.

[Sleep-related breathing disorders in adults: diagnosis, consequences and comorbidities]

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a collapse of the upper airways leading to a decrease (hypopneas) or interruption of air flow (apneas). Since its identification, only forty years ago, definitions, diagnostic techniques have evolved, the consequences of this syndrome have been widely studied but establishing it as an independent cardiovascular (CV) risk factor has come up against the existence of many confounding factors, such as obesity, high blood pressure (hypertension)… Paraclinical diagnosis is based on the results of poly(somno)graphy. Recommendations on measurement techniques and scoring are regularly published, evolving in parallel with technological progress, with the aim of standardizing and ensuring the reliability of the diagnosis. At the same time, large cohort studies were set up in the 1990s, allowing for transversal and longitudinal follow-up of thousands of patients. Finally, the pathophysiological mechanisms of the consequences of SAHOS were explored. OSA has been shown to be responsible for a particularly high accidental risk due to sleep fragmentation induced by abnormal respiratory events. It has been possible to establish an independent statistical relationship between SAHOS and CV diseases, metabolic disorders and more recently cancer, mainly explained by intermittent hypoxia. OSAHOS is a frequent disease, diagnosed on the basis of clinical signs and poly(somno)graphy, now established as an independent risk factor for morbidity and mortality (accidental and CV).

Hyperlipidaemia prevalence and cholesterol control in obstructive sleep apnoea: Data from the European sleep apnea database (ESADA)

BACKGROUND AND OBJECTIVE

Obstructive sleep apnoea (OSA) and hyperlipidaemia are independent risk factors for cardiovascular disease. This study investigates the association between OSA and prevalence of hyperlipidaemia in patients of the European Sleep Apnea Database (ESADA) cohort.

METHODS

The cross-sectional analysis included 11 892 patients (age 51.9 ± 12.5 years, 70% male, body mass index (BMI) 31.3 ± 6.6 kg/m² , mean oxygen desaturation index (ODI) 23.7 ± 25.5 events/h) investigated for OSA. The independent odds ratio (OR) for hyperlipidaemia in relation to measures of OSA (ODI, apnoea-hypopnoea index, mean and lowest oxygen saturation) was determined by means of general linear model analysis with adjustment for important confounders such as age, BMI, comorbidities and study site.

RESULTS

Hyperlipidaemia prevalence increased from 15.1% in subjects without OSA to 26.1% in those with severe OSA, P < 0.001. Corresponding numbers in patients with diabetes were 8.5% and 41.5%, P < 0.001. Compared with ODI quartile I, patients in ODI quartiles II-IV had an adjusted OR (95% CI) of 1.33 (1.15-1.55), 1.37 (1.17-1.61) and 1.33 (1.12-1.58) (P < 0.001), respectively, for hyperlipidaemia. Obesity was defined as a significant risk factor for hyperlipidaemia. Subgroups of OSA patients with cardio-metabolic comorbidities demonstrated higher prevalence of HL. In addition, differences in hyperlipidaemia prevalence were reported in European geographical regions with the highest prevalence in Central Europe.

CONCLUSION

Obstructive sleep apnoea, in particular intermittent hypoxia, was independently associated with the prevalence of hyperlipidaemia diagnosis.

Non-respiratory complaints are main reasons for disturbed sleep post lung transplant

BACKGROUND

Poor sleep is prevalent in lung transplant recipients and affects quality of life negatively. To improve quality of sleep, it's important to identify the causes of poor sleep. We conducted a survey to identify the reasons for poor sleep quality in the recipients.

METHODS

We surveyed lung transplant recipients (2003-2010) at Baylor College of Medicine/The Methodist Hospital lung transplant center. We used a compilation of questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), Berlin Questionnaire, Epworth Sleepiness Scale (ESS) and Short Form 36 (SF36). Descriptive analysis was performed on the responses.

RESULTS

Of the 167 participants, 54 responded (32.3%) with mean age 60.6 years (SD 9.8), 48% male, and a mean post-transplant body mass index (BMI) of 27 (SD 4.7). The responders reported a long mean sleep latency of 33.2 min (SD 32.5), poor sleep quality (74% with PSQI score > 5), excessive daytime sleepiness (ESS > 9 in 29%), poor physical QOL with SF36 mean score of 41.3 (SD 9.4), and high risk for OSA (48.2%). About 30% and 72% reported sleep initiation and maintenance insomnia, respectively. The poor sleep quality was due to "getup to go to bathroom" (85%), "cough or snore loudly" (33%), "have pain" (27.8%), and "feel too cold" (27.8%). Furthermore, 5% reported "Can't breathe comfortably" as reason for poor sleep.

CONCLUSIONS

The recipients reported poor sleep and quality of life. The non-respiratory complaints were important factors for poor sleep. Attention to these factors may help to outline better management strategies to improve sleep in lung transplant recipients.

Obstructive sleep apnoea and cardiovascular disease: a literature review

As obesity becomes more common worldwide, the prevalence of obstructive sleep apnoea (OSA) continues to rise. Obstructive sleep apnoea is a well-known disorder that causes chronic intermittent hypoxia (CIH), which is considered a risk factor for atherosclerosis directly and indirectly. Ischaemic heart disease remains the leading cause of death. Most risk factors for atherosclerosis are well understood. However, other factors such as CIH are less well understood. Several studies have investigated the pathophysiology of CIH, attempting to uncover its link to atherosclerosis and to determine whether OSA treatment can be a therapeutic modality to modify the risk for atherosclerosis. In this article, we will review the pathophysiology of OSA as an independent risk factor for cardiovascular disease and discuss the most common markers that have been studied. We will also examine the potential impact of OSA management as a risk factor modifier on the reversibility of atherosclerosis.

Adrenal gland size in obstructive sleep apnea: Morphological assessment of hypothalamic pituitary adrenal axis activity

OBJECTIVES

The association of obstructive sleep apnea (OSA) with hypothalamic pituitary adrenal (HPA) axis activation has not been fully understood from results of previous studies using hormonal assessments. We aimed to investigate the relationship between adrenal size, a potential marker reflecting HPA axis activity, and sleep parameters related to OSA.

METHODS

We retrospectively reviewed data on 284 consecutive adult patients aged 20 to 80 y who had undergone polysomnography and abdominal computed tomography (CT). OSA was defined as none/mild (apnea-hypopnea index [AHI] <15, n = 75), moderate (AHI 15 to 30, n = 80), and severe OSA (AHI ≥30, n = 129). Widths of adrenal body and limbs were measured by abdominal CT.

RESULTS

Adrenal size was greater in participants with severe OSA than in those with none/mild or moderate OSA (adrenal body width: 6.03 mm, none/mild OSA; 6.09 mm, moderate OSA; 6.78 mm, severe OSA; p <0.001; adrenal limb width: 3.75 mm, none/mild OSA; 3.95 mm, moderate OSA; 4.26 mm, severe OSA, p <0.001). Multivariate regression analysis showed that not the 3% oxygen desaturation index and time of SpO2 <90% but a higher arousal index was the only determinant factor for increased adrenal limb width (β = 0.27, p <0.001) after adjusting for other variables that could affect adrenal size. Neither the arousal index nor hypoxic parameters were associated with adrenal body width.

CONCLUSIONS

Results indicated that adrenal glands may enlarge in response to longstanding sleep fragmentation, suggesting the involvement of OSA in HPA axis augmentation.

Effect modification by gender of the influence of obstructive sleep apnoea characteristics on dyslipidaemia in China: a cross-sectional study

OBJECTIVES

Obstructive sleep apnoea (OSA) characteristics differ by gender, possibly affecting any association between OSA and dyslipidaemia. We explored whether gender influenced any association between OSA characteristics and dyslipidaemia.

METHODS/DESIGN

This was a cross-sectional, large-scale hospital-based study. Male and female risks of dyslipidaemia by OSA characteristics were assessed with logistic regression. Additive interactions were measured using three indices: the relative excess risk due to interaction, the attributable proportion due to interaction and the synergy index. Multiplicative interaction was evaluated via logistic regression.

SETTING

A single secondary-care setting in China.

PARTICIPANTS

3760 patients with OSA.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcomes were male and female risks of dyslipidaemia, and the associated additive and multiplicative interactions between the apnoea-hypopnea index (AHI), the oxygen-desaturation index (ODI), the microarousal index (MAI), and gender.

RESULTS

After controlling for confounding factors, males (but not females) with AHIs>30 were at higher risk of hyper-total cholesterol (TC), hypo-high-density lipoprotein cholesterol (HDL-C) status and a hyper-TC/HDL-C ratio than males with AHIs≤30. Positive additive interactions were evident between the male gender and AHI on a hyper-TC/HDL-C ratio and hypo-HDL-C status. Males with ODIs>40.1 were at higher risk of hypo-HDL-C status and a hyper-TC/HDL-C ratio than males with ODIs≤40.1. Positive additive and multiplicative interactions were evident between male gender and ODI on hyper-TC/HDL-C ratio. Males with MAIs>28.6 were at higher risk of hyper-TC and hyper-low-density lipoprotein cholesterol status than males with MAIs≤28.6, but no statistically significant interactions were apparent between gender and MAI.

CONCLUSIONS

Males (but not females) with higher AHIs, ODIs or MAIs were at higher risks of some measures of dyslipidaemia. Positive interactions between male and severe OSA or intermittent hypoxia on some measures of dyslipidaemia were apparent. Thus, dyslipidaemia should be evaluated in patients with OSA, especially males with severe OSA or intermittent hypoxia.

Symptom Subtypes of Obstructive Sleep Apnea Predict Incidence of Cardiovascular Outcomes

Rationale: Symptom subtypes have been described in clinical and population samples of patients with obstructive sleep apnea (OSA). It is unclear whether these subtypes have different cardiovascular consequences.Objectives: To characterize OSA symptom subtypes and assess their association with prevalent and incident cardiovascular disease in the Sleep Heart Health Study.Methods: Data from 1,207 patients with OSA (apnea-hypopnea index ≥ 15 events/h) were used to evaluate the existence of symptom subtypes using latent class analysis. Associations between subtypes and prevalence of overall cardiovascular disease and its components (coronary heart disease, heart failure, and stroke) were assessed using logistic regression. Kaplan-Meier survival analysis and Cox proportional hazards models were used to evaluate whether subtypes were associated with incident events, including cardiovascular mortality.Measurements and Main Results: Four symptom subtypes were identified (disturbed sleep [12.2%], minimally symptomatic [32.6%], excessively sleepy [16.7%], and moderately sleepy [38.5%]), similar to prior studies. In adjusted models, although no significant associations with prevalent cardiovascular disease were found, the excessively sleepy subtype was associated with more than threefold increased risk of prevalent heart failure compared with each of the other subtypes. Symptom subtype was also associated with incident cardiovascular disease (P < 0.001), coronary heart disease (P = 0.015), and heart failure (P = 0.018), with the excessively sleepy again demonstrating increased risk (hazard ratios, 1.7-2.4) compared with other subtypes. When compared with individuals without OSA (apnea-hypopnea index < 5), significantly increased risk for prevalent and incident cardiovascular events was observed mostly for patients in the excessively sleepy subtype.Conclusions: OSA symptom subtypes are reproducible and associated with cardiovascular risk, providing important evidence of their clinical relevance.

Further Development of P4 Approach to Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a heterogeneous disorder. Cluster analysis has identified different physiologic subtypes with respect to symptoms. A difference exists in cardiovascular risk from OSA between the 7 subtypes identified. There are 3 basic subtypes replicated in multiple studies: (a) a group where insomnia is the main symptom; (b) an asymptomatic group; (c) a group with marked excessive sleepiness. The symptomatic benefit from treatment with nasal CPAP varies between these 3 subtypes. Data from the Sleep Heart Health Study reveal that the increased risk of cardiovascular disease from OSA occurs only in the excessively sleepy group.

Long term management of obstructive sleep apnea and its comorbidities

Obstructive sleep apnea (OSA) is a worldwide highly prevalent disease associated with systemic consequences, including excessive sleepiness, impairment of neurocognitive function and daytime performance, including driving ability. The long-term sequelae of OSA include and increase risk for cardiovascular, cerebrovascular and metabolic syndrome disorders that ultimately lead to premature death if untreated. To ensure optimal long-term outcomes, the assessment and management of OSA should be personalized with the involvement of the appropriate specialist. Most studies have demonstrated inmediate improvement in daytime somnolence and quality of life with CPAP and other therapies, but the effect of long-term treatment on mortality is still under debate. Currently, the long-term management of OSA should be based on a) identifying physiological or structural abnormalities that are treatable at the time of patient evaluation and b) comprehensive lifestyle interventions, especially weight-loss interventions, which are associated with improvements in OSA severity, cardiometabolic comorbidities, and quality of life. In long-term management, attention should be paid to the clinical changes related to a potential reoccurrence of OSA symptoms and it is also necessary to monitor throughout the follow up how the main associated comorbidities evolve.

A Transition Probability Based Classification Model for Enhanced N1 Sleep stage Identification During Automatic Sleep Stage Scoring

Automatic sleep staging provides a cheaper, faster and more accessible alternative for evaluating sleep patterns and quality compared with manual hypnogram scoring performed by a clinician. Traditionally, classification methods treat sleep stages independently of their temporal order, despite sleep patterns themselves being highly sequential. Such independent sleep stage classification can result in poor sensitivity and precision, in particular when attempting to classify the sleep stage N1, otherwise known as the transition stage of sleep which links periods of wakefulness to periods of deep sleep. To this end, we propose a novel transition sleep classification method which aims to improve classification accuracy. This is achieved by utilising both the temporal information of previous stages and treating the transitions between stages as classes in their own right. Simulations on publicly available polysomnography (PSG) data and a comprehensive performance comparison with standard classifiers demonstrate a marked improvement achieved by the proposed method in both N1 sensitivity and precision across all considered classifiers. This includes an increase in N1 precision from 0.01% to 36.75% in an MLP classifier, and an increase in both accuracy and Cohen's kappa value in two of the three classifiers. Overall best mean performance is obtained by transition classification with a random forest classifier (RF) which achieved a kappa value of κ = 0.75 (substantial agreement), and an N1 stage precision of 58%.

Sleep Quality and Blood Lipid Composition Among Patients with Diabetes

BACKGROUND

Recent literature has mentioned that people with sleep disorder, experience insulin sensitivity reduction and accordingly higher levels of blood glucose.

OBJECTIVES

This study aimed to investigate the relationship between sleep quality and blood lipid composition in patients with diabetes referring to Minoodar health center in Qazvin, Iran in 2017.

METHODS

Sleep duration and quality were assessed in 347 patients with diabetes using the Pittsburgh sleep quality index (PSQI). The glycosylated hemoglobin A1c (HbA1c) test was used to measure the glycemic control and total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and high-density lipoprotein cholesterol (HDL-C) were used to determine blood lipid composition of the patients. Multiple regression analyses were applied to examine the associations between sleep measures and HbA1c and lipid parameters using SPSS version 20.

RESULTS

The patients in the poor sleep quality group had higher levels of fasting blood sugar (FBS) (146.07 ± 57.06 versus 132.8 ± 53.3 mg/dL, P = 0.02), body mass index (BMI) (29.1 ± 3.9 versus 27.6 ± 4.2 kg/m², P = 0.005) and total cholesterol (209.9 ± 53.4 versus 193.4 ± 45.8, P = 0.02). Furthermore, the patients with short sleep duration had higher total cholesterol level compared with long sleep and medium sleep duration group (202.3 ± 50.2 versus 196.6 ± 47.7 and 195.7 ± 47.4, respectively, P = 0.05). Among different PSQI measures, subjective sleep quality was associated with lower TC and TG in unadjusted models (β = -0.0.1, P = 0.05). Furthermore, greater sleep disturbance was positively linked with higher levels of TC and TG (β = 0.1, P = 0.01 and β = 0.02, P = 0.05).

CONCLUSIONS

In an Iranian population with diabetes living in Qazvin city, sleep disorder is common and as study findings revealed sleep quality was recognized as an influencing factor on some of the lipid profiles, including TC and TG. Thus sleep assessment of patients with type 2 diabetes to find the early recognition of their sleep disorder should be considered an important part of the patients' treatment.

Sex Differences in the Association Between Smoking and Sleep-Disordered Breathing in the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Results of previous studies examining associations between cigarette smoking and sleep-disordered breathing (SDB) are inconsistent. We therefore investigated this association in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

METHODS

A total of 13,863 US Hispanic/Latino subjects, 18 to 76 years old, provided smoking histories and underwent home SDB testing. Logistic regression analyses were conducted to assess the independent association of smoking and SDB with covariate adjustment. Sex- and age-stratified analyses were performed.

RESULTS

The weighted prevalence of moderate to severe SDB was 9.7% (95% CI, 9.0-10.5). No independent and statistically significant association was observed between ever smoking (defined as minimum lifetime cigarette use of 100) and moderate to severe SDB (defined as an apnea-hypopnea index ≥ 15 events per hour) (OR, 1.02; 95% CI, 0.85-1.22; P = .85). Sex and age were effect modifiers of the aforementioned association. Stratification according to age and sex revealed that younger (aged 35-54 years) female smokers had 83% higher odds of SDB compared with younger female never smokers (OR, 1.83; 95% CI, 1.19-2.81; P = .01). A significant dose-response relation was noted between smoking intensity and SDB in younger female smokers (P < .01). Lastly, use of ≥ 10 cigarettes per day was associated with a nearly threefold increase in SDB odds in younger female ever smokers. These associations were not observed in younger male subjects.

CONCLUSIONS

In the HCHS/SOL, no independent and statistically significant association was found between smoking and SDB. Sex and age stratification revealed a novel statistically significant association between smoking and SDB in younger (35-54 years old) female smokers. Our findings highlight the importance of investigating sex- and age-specific associations of SDB risk factors.

The Clinical Significance of Apneas Versus Hypopneas: Is There Really a Difference?

Introduction

Obstructive sleep apnea is diagnosed by identifying obstructive apneas and hypopneas, but no study has shown that it is necessary to distinguish these events from each other. Our goal was to analyze results from polysomnograms to determine if adverse health outcomes were more likely in patients with higher apnea indices relative to their hypopnea indices. Our hypothesis was that scoring apneas separately from hypopneas has no predictive value.

Methods

A retrospective case series was performed for consecutive diagnostic and split-night polysomnograms with apnea-hypopnea indices greater than five per hour. Clinical data reviewed included the presence of cardiovascular diseases, hypertension, depression, and migraine. Both univariate and multivariate analyses were performed to look for correlations between polysomnographic indices and the comorbidities.

Results

Three hundred fifty-one records were included. Univariate analysis showed no significant difference between the apnea index (AI) and hypopnea index (HI) based on the presence of any of the comorbidities. Multivariate logistic regression also indicated no significant association between indices and comorbidities, aside from one statistically significant correlation between a higher HI and depression.

Conclusions

Clinical comorbidities are no more likely in patients with higher apnea indices than hypopnea indices. While apneas are considered a more severe form of obstruction, this distinction does not have any known clinically predictive value. This finding raises the question as to whether scoring hypopneas and apneas as different events on polysomnograms is necessary or helpful. Scoring apneas and hypopneas as “obstructions” could save resources and increase inter-scorer reliability.

Obstructive Sleep Apnea and Hypertension: Why Treatment Does Not Consistently Improve Blood Pressure

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) and hypertension are two phenomena deeply linked together and, although a causal relationship has been suggested, a recent meta-analysis showed only a very modest effect of OSA treatment on blood pressure (BP). However, a vast number of randomized controlled trials published so far share some limitations, mainly of methodological nature: neither OSA nor BP is always assessed in a standardized way. Moreover, compliance with OSA treatment is often sub-optimal making the results of these trials difficult to interpret.

RECENT FINDINGS

Recent studies have shown that antihypertensive drugs can reduce BP more than OSA treatment, showing a better compliance profile and very few side effects. Considering the importance of reducing the overall cardiovascular risk of OSA patients, a more careful management of patient's antihypertensive medication could allow a better BP control also in this condition. In addition, greater efforts should be made to improve patient's acceptance of OSA treatment with the aim of improving their compliance.

The association between obstructive sleep apnea syndrome and metabolic syndrome: a confirmatory factor analysis

BACKGROUND

Growing evidence suggests an independent relationship between obstructive sleep apnea syndrome (OSAS) and metabolic syndrome (MS). Patients with OSAS always show clustering of metabolic components. However, the understanding of interplay between OSAS and metabolic components is still lacking.

METHODS

Participants were consecutively enrolled from our sleep center during the period 2009-2013. Anthropometric variables, metabolic indicators, and sleep parameters were collected from all participants. The factor structure for MS in OSAS and non-OSAS was examined by confirmatory factor analysis.

RESULTS

The OSAS and non-OSAS demonstrated clustering of metabolic components. MS in patients with OSAS was strongly associated with insulin resistance (standardized factor loading = 0.93, p < 0.001), obesity (loading = 0.92, p < 0.001), and the lipid profile (loading = 0.72, p < 0.001). Furthermore, insulin resistance was correlated with obesity and lipid profile (r = 0.86, p < 0.001; r = 0.68, p < 0.001, respectively). Obesity and lipid profile were also highly correlated in OSAS (r = 0.66, p < 0.001). In non-OSAS, MS was strongly associated with insulin resistance, obesity, and lipid profile (loading = 0.95, p < 0.001; loading = 0.74, p < 0.001; loading = 0.68, p < 0.001, respectively). Insulin resistance was most strongly associated with fasting insulin (loading = 0.65, p < 0.001). Lipid profile was most strongly associated with TG (loading = 0.88, p < 0.001). Obesity was most strongly associated with BMI (loading = 0.80, p < 0.001).

CONCLUSIONS

OSAS is more prone to show clustering of metabolic components compared with non-OSAS. In particular, insulin resistance, obesity, and the lipid profile were independently and strongly correlated with MS in OSAS.

Elevated Serum Markers of Acute Kidney Injury in Patients With Obstructive Sleep Apnea

STUDY OBJECTIVES

Previous research revealed a positive correlation between endothelial cell injury (indicated by albuminuria) and obstructive sleep apnea (OSA). However, little else has been revealed about acute kidney injury (AKI) in patients with OSA.

METHODS

This prospective study recruited consecutive patients undergoing overnight polysomnography for evaluation of sleep apnea. Patients in whom any major disease or recent infection had been previously diagnosed were excluded. Ultimately, data from 75 patients with apnea-hypopnea indices of 5 or more were analyzed. Baseline values for the urinary albumin-creatinine ratio (UACR), serum levels for three markers of AKI (cystatin C, neutrophil gelatinase-associated lipocalin [NGAL], interleukin-18 [IL-18]), and polysomnography data were recorded and analyzed. Patients then were followed for 6 months of continuous positive airway pressure (CPAP) treatment.

RESULTS

At baseline, UACRs were greater in patients with more severe OSA (P = .005, r = .329). All three serum markers of AKI (cystatin C, NGAL, and IL-18) studied were positively correlated with OSA severity, and two (cystatin C and IL-18) were positively correlated with the frequency of oxygen desaturation during sleep. However, none of the AKI markers had positive correlations with UACR. After 6 months of CPAP treatment, UACR and IL-18 were decreased significantly in patients with good adherence.

CONCLUSIONS

Albuminuria and levels of three serum markers of AKI (cystatin C, NGAL, IL-18) were positively correlated with OSA severity, and good adherence with CPAP treatment decreased albuminuria and interleukin-18 levels. These results may provide additional tools for assessing early renal injury in patients with OSA.

An orthodontic-orthognathic patient with obstructive sleep apnea treated with Le Fort I osteotomy advancement and alar cinch suture combined with a muco-musculo-periosteal V-Y closure to minimize nose deformity

In some severe skeletal Class III patients, mandibular setback surgery using sagittal split ramus osteotomy (SSRO) is performed to correct mandibular protrusion. However, in patients diagnosed with obstructive sleep apnea syndrome (OSAS), the risk of OSAS worsening as a result of the SSRO is very high. Maxillary advancement could reduce the degree of mandibular retropositioning and expand the skeletal framework in the pharyngeal region, leading to enlargement of the airway. However, nasal deformity is an undesirable outcome of the procedure. This case report describes a 23-year-old man with a retruded maxilla and OSAS. The maxillary retrusion was treated using Le Fort I osteotomy with an alar cinch suture and a muco-musculo-periosteal V-Y closure (ACVY). After treatment, better occlusal relationships and improvement in OSAS were observed. Thus, an ACVY could minimize nasolabial deformity.

Sympathetic Hyperactivity and Sleep Disorders in Individuals With Type 2 Diabetes

Introduction: Many studies on the impact of type 2 diabetes mellitus (T2DM) on sleep breathing have shown a higher prevalence and severity of sleep apnea-hypopnea syndrome (SAHS) in those with T2DM. Moreover, an increased activity of the sympathetic nervous system has been described in both pathologies. This cross-sectional study aimed to assess sympathetic activity in patients with T2DM, and to investigate the relationship between sympathetic activity and polysomnographic parameters. Materials and Methods: Thirty-six patients with T2DM without known clinical macrovascular nor pulmonary disease and 11 controls underwent respiratory polygraphy, and their cardiac variability and 24-h urine total metanephrines were measured. Results: SAHS was highly prevalent with a mean apnea-hypopnea index (AHI) in the range of moderate SAHS. In patients with T2DM, the nocturnal concentration of total metanephrines in urine were higher than diurnal levels [247.0 (120.0-1375.0) vs. 210.0 (92.0-670.0), p = 0.039]. The nocturnal total metanephrine concentration was positively and significantly associatedwith the percentage of sleeping time spent with oxygen saturation <90%(CT90). In the entire population and in subjects with T2DM, the multivariate regression analysis showed a direct interaction between the nocturnal concentration of urine metanephrines and the CT90. Conclusion: These findings suggest that the increase in sympathetic activity previously described in patients with T2DM could be mediated through nocturnal breathing disturbances. The diagnosis and treatment of SAHS may influence sympathetic activity disorders and may contribute to an improvement in T2DM and cardiovascular risk.

Sleep-Disordered Breathing Is Associated with Metabolic Syndrome in Outpatients with Diabetes Mellitus Type 2

BACKGROUND

Metabolic syndrome (MS) and sleep-disordered breathing (SDB) are highly prevalent in patients with diabetes mellitus type 2 (DM2). The present study examined whether there is an independent association between SDB and MS in a sample of outpatients with DM2.

METHODS

MS was determined in 679 patients of the DIACORE-SDB substudy, a study of outpatients with DM2. According to the National Cholesterol Education Program (NCEP) criteria, MS is defined by at least three of the following five criteria: waist circumference of >102 cm (men)/>88 cm (women), blood pressure of ≥130/85 mmHg, a fasting triglyceride level of >150 mg/dl, high-density lipoprotein (HDL) of <40 mg/dl (men)/<50 mg/dl (women), and a fasting glucose level of ≥110 mg/dl. The apnea-hypopnea index (AHI) was assessed with a 2-channel ambulatory monitoring device and used to define the severity of SDB (AHI < 15.0: no/mild SDB; AHI 15.0-29.9: moderate SDB; AHI ≥ 30.0: severe SDB).

RESULTS

228 (34%) of the 679 participants (mean age 66 years, mean body mass index (BMI) 31.2 kg/m², and mean AHI 14/hour) had SDB. MS was significantly more frequent in patients with more severe SDB (no/mild SDB vs. moderate SDB vs. severe SDB: 72% vs. 79% vs. 85%, respectively, p = 0.038). Logistic regression analysis adjusted for sex, age, obesity (BMI ≥ 30 kg/m²), and the HOMA index showed a significant association between the AHI and the presence of MS (OR (95%CI) = 1.039 (1.011; 1.068); p = 0.007). Further, male sex, obesity, and the HOMA index were significantly associated with MS.

CONCLUSION

SDB is significantly and independently associated with MS in outpatients with DM2.

Derivation and validation of a clinical prediction rule for sleep apnoea syndrome for use in primary care

Background

Several clinical prediction rules (CPRs) are available for sleep apnoea-hypopnoea syndrome (OSAH), but they are difficult to apply in primary care (PC).

Aim

Derivation and validation of a CPR using simple measurements available in PC.

Design & setting

A prospective study conducted in health centres from the area of influence of three Spanish hospitals.

Method

Patients (aged 18–70 years) who attended for any reason; who presented with at least one of the three key symptoms for OSAH (snoring, breathing pauses while sleeping, and daytime sleepiness); and who were not undergoing non-invasive ventilation or prior treatment with continuous positive airway pressure (CPAP) were included. Anthropometric data, smoking habit, comorbidities, and Epworth test were collected. Patients were subsequently referred to the sleep unit (SU), where the decision was taken whether or not to instigate treatment. A multivariate logistic model was constructed using a sub-sample and scores assigned based on the regression coefficients; the CPR was validated with the remaining sample. Both receiver operating characteristic (ROC) curves were plotted and the sensitivity, specificity, and predictive values calculated.

Results

The derivation sample comprised 352 patients, with 260 in the validation sample. The final factors (arterial hypertension [AHT], age, body mass index [BMI], and sex) were used to develop a rule with scores ranging from 0.00–5.50. The cut-off point that optimises the area under the curve (AUC) is ≥2.50 points (AUC = 0.78; sensitivity = 86%; specificity = 54%; positive predictive value [PPV] = 45%; negative predictive value [NPV] = 90%; likelihood ratio [LR] = 0.26). The properties for the validation sample with this cut-off point are as follows: AUC = 0.68; sensitivity = 81%; specificity = 43%; PPV = 61%; NPV = 68%; LR = 0.44.

Conclusion

As in similar cases, the specificity is low, meaning that healthy people are referred to a specialist. A negative result rules out the disease in most cases.

Hematological indices as simple, inexpensive and practical severity markers of obstructive sleep apnea syndrome: a meta-analysis

Background

Clinical detection of inflammatory markers is useful to assess the degree of nocturnal hypoxia and predict the presence of complications in obstructive sleep apnea syndrome (OSAS) patients. Nowadays, some researchers proposed that hematological parameters could be substituted for novel disease-specific biochemical markers (such as C-reactive protein) because they were comparatively cheap, simple and practical. But there was a contradiction whether the hematological parameters were positively correlated with the OSAS severity.

Methods

Medical databases were searched included PubMed, Web of Science, Scopus, Cochrane Library, Clinical Trial, Embase and Google Scholar (up to March 29, 2018). We used weighted mean differences (WMDs) with 95% confidence intervals (CIs) from random-effects model.

Results

Seventeen studies were included in this meta-analysis and results were presented by different hematological parameters. Pooled analysis showed that OSAS was associated with a high level of WBC (white blood cell, 11 studies, 2,206 subjects, WMD: 0.58; 95% CI: 0.31 to 0.85; P<0.0001), NLR (neutrophil-to-lymphocyte ratio, 5 studies, 1416 subjects, WMD: 0.46; 95% CI: 0.13 to 0.80; P=0.007), MPV (mean platelet volume, 8 studies, 1,854 subjects, WMD: 0.63; 95% CI: 0.29 to 0.98; P=0.0004), PDW (platelet distribution width, 6 studies, 1,911 subjects, WMD: 0.76; 95% CI: 0.47 to 1.06; P<0.00001), PLR (platelet-to-lymphocyte ratio, 3 studies, 998 subjects, WMD: 21.76; 95% CI: 8.54 to 34.99; P=0.001), RDW (red cell distribution width, 5 studies, 1,701 subjects, WMD: 0.31; 95% CI: 0.11 to 0.51; P=0.002) and HCT (hematocrit, 3 studies, 662 subjects, WMD: 1.58; 95% CI: 0.52 to 2.64; P=0.003). But OSAS was associated with a low level of LYM (lymphocyte, 5 studies, 1,285 subjects, WMD: -0.27; 95% CI: -0.49 to -0.06; P=0.01). There was a gradual rising trend from mild OSAS to severe OSAS existed in all subgroups.

Conclusions

Hematological indices are comparatively Simple, Inexpensive and Practical Severity Markers of OSAS including WBC, LYM, NLR, MPV, PDW, PLR, RDW and HCT.

Patterns of adenoid and tonsil growth in Japanese children and adolescents: A longitudinal study

Lymphoid tissues, such as adenoids (Ad) and tonsils (Tn), are suggested to undergo hypertrophy during childhood and involution in adulthood. Enlargement of Ad and Tn can cause transient obstruction of the respiratory airways, thus inducing obstructive sleep apnoea. To date, the standard Ad and Tn sizes have not been reported, and there are no explicit objective criteria for evaluating their sizes or deducing whether they have enlarged, reduced, or remained constant over time. Our previous cross-sectional study revealed the age-dependent airway occupation ratio of Ad and Tn in Japanese individuals. We conducted a longitudinal observational study of the Ad and Tn sizes in Japanese individuals aged 6–20 years. Ninety individuals were retrospectively enrolled. The average and standard deviation of the sizes was calculated in 5 age-based groups.

Prevalence and association analysis of obstructive sleep apnea with gender and age differences - Results of SHIP-Trend

Identification of obstructive sleep apnea and risk factors is important for reduction in symptoms and cardiovascular risk, and for improvement of quality of life. The population-based Study of Health in Pomerania investigated risk factors and clinical diseases in a general population of northeast Germany. Additional polysomnography was applied to measure sleep and respiration with the objective of assessing prevalence and risk factors of obstructive sleep apnea in a German cohort. One-thousand, two-hundred and eight people between 20 and 81 years old (54% men, median age 54 years) underwent overnight polysomnography. The estimated obstructive sleep apnea prevalence was 46% (59% men, 33% women) for an apnea-hypopnea index ≥5%, and 21% (30% men, 13% women) for an apnea-hypopnea index ≥ 15. The estimated obstructive sleep apnea syndrome prevalence (apnea-hypopnea index ≥5; Epworth Sleepiness Scale >10) was 6%. The prevalence of obstructive sleep apnea continuously increased with age for men and women with, however, later onset for women. Gender, age, body mass index, waist-to-hip ratio, snoring, alcohol consumption (for women only) and self-reported cardiovascular diseases were significantly positively associated with obstructive sleep apnea, whereas daytime sleepiness was not. Diabetes, hypertension and metabolic syndrome were positively associated with severe obstructive sleep apnea. The associations became non-significant after adjustment for body mass. Women exhibited stronger associations than men. The prevalence of obstructive sleep apnea was high, with almost half the population presenting some kind of obstructive sleep apnea. The continuous increase of obstructive sleep apnea with age challenges the current theory that mortality due to obstructive sleep apnea and cardiovascular co-morbidities affect obstructive sleep apnea prevalence at an advanced age. Also, gender differences regarding obstructive sleep apnea and associations are significant for recognizing obstructive sleep apnea mechanisms and therapy responsiveness.

Prevalence and correlates of obstructive sleep apnea among African Americans: the Jackson Heart Sleep Study

Study Objectives

African Americans have been under-represented in obstructive sleep apnea (OSA) research. This study determined the prevalence and correlates of OSA overall and by sex among African Americans in the Jackson Heart Sleep Study.

Methods

Participants (N = 852) underwent a type 3 in-home sleep apnea study, 7 day wrist actigraphy and completed standardized measurements and questionnaires. OSA was defined as an apnea-hypopnea index (AHI) of ≥15, where hypopneas were defined as ≥ 4% associated desaturation. Physician diagnosis of OSA was self-reported. Logistic regression models were fit to determine the associations of demographics, socioeconomic status, sleep symptoms, actigraphy-based sleep, body mass index (BMI), and comorbidities with OSA.

Results

Average age was 63.1 (standard deviation = 10.7), 66% were female, and mean BMI was 32.0 (6.9) kg/m2. Approximately 24% had an AHI ≥ 15; of those, 5% had a physician diagnosis of OSA. Prevalence of OSA increased across BMI categories, but not age groups. Men had a 12% higher prevalence of OSA compared with women, p < 0.01. Older age, male sex, higher BMI, larger neck circumference, and report of habitual snoring were independently associated with higher odds of OSA, all p < 0.05. Associations between sleep symptoms and OSA were similar for men and women. Sleepiness and waist circumference were not associated with OSA.

Conclusions

There was a high prevalence of objectively measured but undiagnosed OSA in this sample of African Americans. Snoring, BMI, and neck circumference were important markers of OSA for men and women. Our results suggest that screening tools that incorporate information on sleepiness and waist circumference may be suboptimal in this population.

Association between obstructive sleep apnea syndrome and waist-to-height ratio

PURPOSE

Obesity is among the known risk factors for obstructive sleep apnea syndrome (OSAS). In this study, our aim was to investigate the correlation of waist-to-height ratio, an indicator of central obesity, with presence and severity of OSAS; to compare the use of this ratio with the use of waist circumference and body mass index (BMI); and to determine OSAS-related cutoff values.

METHODS

The patient records were retrospectively analyzed for whom a polysomnography was conducted at our sleep. Sex, age, Apnea-Hypopnea Index (AHI), waist circumference, height, and BMI values of those patients were recorded. AHI scores were used to classify severity of OSAS.

RESULTS

The study included 437 OSAS patients and 72 control cases. Out of the patient group, OSAS was severe in 208 (47%) patients, moderate in 124 (28%), and mild in 105 (24%) of them. In the group of OSAS patients, waist-to-height ratio, waist circumference, and BMI were higher compared to the control group with a further difference of all three parameters among severe, moderate, mild OSAS, and controls both in males and females. Cutoff values for OSAS of females were 95.5 cm for waist circumference, 0.595 for waist-to-height ratio, and 27.75 for BMI whereas the cutoff values of males were 100.5 cm, 0.575, and 27.75, respectively.

CONCLUSIONS

A high value of waist circumference, waist-to-height ratio, and BMI is associated with the presence and severity of OSAS. We have determined the cutoff values of the studied anthropometric measurements in both sexes for OSAS and severe OSAS.

Obstructive sleep apnoea independently predicts lipid levels: Data from the European Sleep Apnea Database

BACKGROUND AND OBJECTIVE

Obstructive sleep apnoea (OSA) and dyslipidaemia are independent risk factors for cardiovascular disease. This study investigates the association between OSA and plasma lipid concentrations in patients enrolled in the European Sleep Apnea Database (ESADA) cohort.

METHODS

The cross-sectional analysis included 8592 patients without physician-diagnosed hyperlipidaemia or reported intake of a lipid-lowering drug (age 50.1 ± 12.7 years, 69.1% male, BMI: 30.8 ± 6.6 kg/m² , mean apnoea-hypopnoea index (AHI): 25.7 ± 25.9 events/h). The independent relationship between measures of OSA (AHI, oxygen desaturation index (ODI), mean and lowest oxygen saturation) and lipid profile (total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and fasting triglycerides (TG)) was determined by means of general linear model analysis.

RESULTS

There was a dose response relationship between TC and ODI (mean ± SE (mg/dL): 180.33 ± 2.46, 184.59 ± 2.42, 185.44 ± 2.42 and 185.73 ± 2.44; P < 0.001 across ODI quartiles I-IV). TG and LDL concentrations were better predicted by AHI than by ODI. HDL-C was significantly reduced in the highest AHI quartile (mean ± SE (mg/dL): 48.8 ± 1.49 vs 46.50 ± 1.48; P = 0.002, AHI quartile I vs IV). Morbid obesity was associated with lower TC and higher HDL-C values. Lipid status was influenced by geographical location with the highest TC concentration recorded in Northern Europe.

CONCLUSION

OSA severity was independently associated with cholesterol and TG concentrations.

Association between Obstructive Sleep Apnea and Cardiovascular Risk Factors: Variation by Age, Sex, and Race. The Multi-Ethnic Study of Atherosclerosis

RATIONALE

The association between obstructive sleep apnea (OSA) and cardiovascular disease (CVD) is complex, bidirectional, and may vary across groups. Understanding which cardiovascular risk factors vary in their relationship to OSA across population groups may improve knowledge of OSA-related CVD susceptibility.

OBJECTIVES

To better understand the heterogeneity of associations, we assessed whether associations of OSA with cardiovascular risk factors vary by age, sex, and race/ethnicity.

METHODS

We performed cross-sectional analyses of 1,344 Multi-Ethnic Study of Atherosclerosis participants who underwent overnight full polysomnography, assays of fasting blood, and assessments of cardiovascular risk factors. Risk factors considered were blood pressure, glucose/lipid concentrations, white blood cell (WBC) total and subset counts, and cystatin C. The outcome was the apnea-hypopnea index (AHI). Linear regression analyses with tests for interactions were conducted.

RESULTS

The sample had a mean age of 68 ± 9 years. Forty-seven percent of the sample was male, and 32% had moderate or severe OSA (AHI, ≥15). Multivariable adjusted analysis showed significant associations between higher AHI with lower high-density lipoprotein cholesterol and higher diastolic blood pressure and neutrophil counts. Significant interactions with demographic factors were observed. Stronger associations were shown between AHI and higher total WBC count (Pint = 0.006) and glucose concentrations (Pint = 0.006) in younger (<65 yr) than in older individuals, higher triglyceride concentrations in men than in women (Pint = 0.006), and higher total WBC (Pint = 0.07) and monocyte counts (Pint = 0.03) in African American individuals than in other racial groups.

CONCLUSIONS

In a multiethnic cohort, we found increased levels of cardiovascular risk factors in association with OSA, including elevated neutrophil counts, a marker of inflammation. Furthermore, several associations were stronger in men, younger individuals, and African American individuals, highlighting pathways for CVD risk that may explain heterogeneity in the associations between CVD and OSA across population groups.

Association of sleep disturbances with obesity, insulin resistance and the metabolic syndrome

Insufficient sleep, which has become endemic in recent years, has been variably associated with increased risk of obesity, disorders of glucose and insulin homeostasis, and the metabolic syndrome; to a lesser degree, so has excessive sleep. This review summarizes recent epidemiological and pathophysiological evidence linking sleep disturbances (primarily abnormalities of sleep duration) with obesity, insulin resistance, type 2 diabetes and the metabolic syndrome in children and adults.

Sleep: important considerations for the prevention of cardiovascular disease

PURPOSE OF REVIEW

Sleep plays many roles in maintenance of cardiovascular health. This review summarizes the literature across several areas of sleep and sleep disorders in relation to cardiometabolic disease risk factors.

RECENT FINDINGS

Insufficient sleep duration is prevalent in the population and is associated with weight gain and obesity, inflammation, cardiovascular disease, diabetes, and mortality. Insomnia is also highly present and represents an important risk factor for cardiovascular disease, especially when accompanied by short sleep duration. Sleep apnea is a well-characterized risk factor for cardiometabolic disease and cardiovascular mortality. Other issues are relevant as well. For example, sleep disorders in pediatric populations may convey cardiovascular risks. Also, sleep may play an important role in cardiovascular health disparities.

SUMMARY

Sleep and sleep disorders are implicated in cardiometabolic disease risk. This review addresses these and other issues, concluding with recommendations for research and clinical practice.

Convergence in Sleep Time Accomplished? Gender Gap in Sleep Time for Middle-Aged Adults in Korea

Although the gender gap in sleep time has narrowed significantly in the last decade, middle-aged women between ages 35 and 60 still sleep less than their male counterparts in Korea. This study examines and provides evidence for factors contributing to the gender gap in this age group. Using Korean Time Use Survey (KTUS) data from 2004, 2009 and 2014, we find that middle-aged women&rsquo;s difficulty in managing work-life balance and traditional role expectations placed upon women are the main causes of the gender gap in sleep time. The decomposition analysis reveals that the improved socioeconomic status and recent changes in familial expectations for women may have helped them sleep more than in the past. However, there remain fundamental differences in attitude and time use patterns between men and women that prevent middle-aged women from getting the same amount of sleep.

Chronic intermittent hypoxia induces hormonal and male sexual behavioral changes: Hypoxia as an advancer of aging

Sleep apnea is a common sleep disorder characterized by intermittent periods of low blood oxygen levels. The risk for sleep apnea increases with age and is more prevalent in men than women. A common comorbidity of sleep apnea includes male sexual dysfunction, but it is not clear if a causal relationship exists between sleep apnea and sexual dysfunction. Possible mechanisms that link these two disorders include oxidative stress and testosterone. Oxidative stress is elevated in clinical patients with sleep apnea and in rodents exposed to chronic intermittent hypoxia (CIH), an animal model for apnea-induced hypopnea. Further, oxidative stress levels increase with age. Therefore, age may play a role in sleep apnea-induced sexual dysfunction and oxidative stress generation. To investigate this relationship, we exposed gonadally intact 3 (young) and 12 (middle-aged) month old male F344/BN F1 hybrid male rats to 8 days of CIH, and then examined male sexual function. Plasma was used to assess circulating oxidative stress and hormone levels. Middle-aged male rats had lower testosterone levels with increased sexual dysfunction and oxidative stress, independent of CIH. However, CIH decreased testosterone levels and increased sexual dysfunction and oxidative stress only in young gonadally intact male rats, but not in gonadectomized young rats with physiological testosterone replacement. In sum, CIH had a greater impact on younger gonadally intact animals, with respect to sexual behaviors, testosterone, and oxidative stress. Our data indicate CIH mimics the effects of aging on male sexual behavior in young gonadally intact male rats.

Prevalence, sleep characteristics, and comorbidities in a population at high risk for obstructive sleep apnea: A nationwide questionnaire study in South Korea

Objective

To determine the prevalence, sleep characteristics, and comorbidities associated with a high risk for obstructive sleep apnea (OSA) in the Korean adult population.

Methods

We analyzed data from 2,740 subjects who responded to a nationwide questionnaire survey of sleep characteristics. Those who qualified under two or more symptom categories of the Berlin questionnaire were defined as “at high risk for OSA”. We investigated their socio-demographic information, sleep habits, and medical and psychiatric comorbidities. Logistic regression analyses were performed to identify factors and consequences significantly associated with a high risk for OSA.

Results

The prevalence of a high risk for OSA was 15.8% (95% confidence interval [CI] 14.5–17.2%). Multiple logistic regression analysis showed that old age (≥ 70 years, odds ratio [OR] 2.68) and body mass index ≥ 25 kg/m² (OR 10.75) were significantly related with a high risk for OSA, whereas regular physical activity (OR 0.70) had a protective effect. Subjective sleep characteristics associated with a high risk for OSA were perceived insufficient sleep (OR 1.49), excessive daytime sleepiness (OR 1.88), and insomnia (OR 3.70). In addition, hypertension (OR 5.83), diabetes mellitus (OR 2.54), hyperlipidemia (OR 2.85), and anxiety (OR 1.63) were comorbid conditions independently associated with a high risk for OSA.

Conclusions

This is the first study to demonstrate the prevalence of a high risk for OSA in a nationwide representative sample of the Korean adult population. These findings elucidate the epidemiology and clinical characteristics of those at high risk for OSA.

APOEε4 and slow wave sleep in older adults

Slow wave (or stage N3) sleep has been linked to a variety of cognitive processes. However, the role of stage N3 in the elderly is debated. The link between stage N3 and episodic memory may be weakened or changed in the older adult population, possibly due to several altered mechanisms impacting the cellular structure of the brain. The bases for the age-related dissociation between stage N3 and cognition are not understood. Since APOEε4 status is the strongest genetic risk factor for cognitive decline, we assessed whether the ε4 allele is associated with stage N3 sleep. Participants were from the population-based Osteoporotic Fractures in Men (MrOS) cohort with polysomnography and APOEε4 genotype data (n = 2,302, 100% male, mean age 76.6 years). Sleep stages were objectively measured using overnight in-home polysomnography and central electroencephalogram data were used to score stage N3 sleep. Cognitive function was assessed using the Modified Mini Mental State Exam (3MS). The APOE rs429358 single nucleotide polymorphism, which defines the APOEε4 allele, was genotyped using a custom genotyping array. Total time in stage N3 sleep was significantly higher (p<0.0001) among the 40 MrOS participants carrying two copies of the ε4 allele (62±5.2 minutes) compared with 43±1.5 minutes for carriers of one ε4 allele (n = 515) and 40±0.8 minutes for ε4 non-carriers (n = 1747). All results were independent of sleep efficiency, number of sleep cycles, and apnea hypopnea index. These findings support an association between APOEε4 genotype and sleep stage N3 in the elderly. Increased total stage N3 duration among ε4/ε4 carriers does not appear to reflect compensation for prior cognitive decline and may reflect overactive downscaling of synapses during sleep. If confirmed, these results might in part explain the high risk of age-related cognitive decline and AD among APOE ε4/ε4 carriers.

Endothelin contributes to the blood pressure rise triggered by hypoxia in severe obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is strongly correlated with an increased risk of systemic hypertension. However, the link between systemic hypertension and nocturnal apneas remains incompletely understood. Animal studies suggest an implication of the endothelin system. The aim of the present study is to determine if endogenous endothelin plays a role in the increase in blood pressure observed during hypoxic episodes in OSA patients, in addition to peripheral chemoreflex and neural sympathetic activation.

METHODS

We assessed the effects of the nonspecific endothelin antagonist bosentan (500 mg; Tracleer; Actelion; Basel, Switzerland) on ventilation, hemodynamics, and muscle sympathetic nerve activity (MSNA) during normoxia and isocapnic hypoxia using a randomized, crossover, double-blinded, placebo-controlled study design, and in 13 severely untreated sleep apneic patients (age 50 ± 9 years, apnea-hypopnea index 35 ± 21/h).

RESULTS

Hypoxia increased blood pressure, MSNA, and minute ventilation as oxygen saturation decreased. Bosentan suppressed completely the increase in SBP during a 5-min hypoxic challenge (143 ± 5 mmHg during hypoxia vs. 133 ± 5 mmHg during normoxia with placebo and 127 ± 3 mmHg during hypoxia vs. 125 ± 3 mmHg during normoxia under bosentan, P = 0.023). DBP as well as the rise in MSNA and ventilation during isocapnic hypoxia did not differ between bosentan and placebo.

CONCLUSION

Endothelin contributes to the rise in SBP in response to acute hypoxia in patients with severely untreated OSA. This was not due to lower chemoreflex activation with bosentan.

Determinants of obstructive sleep apnea syndrome: Pro-inflammatory state and dysfunction of high-density lipoprotein

OBJECTIVE

The goal of this study was to determine variables preceding and predicting incident obstructive sleep apnea syndrome (OSAS) in the population at large.

METHODS

Anthropometric, lipid, and non-lipid variables in participants with newly developing OSAS (n = 131) were compared with those of a cohort sample (n = 2615) of the Turkish Adult Risk Factor study. Available values preceding (by a median of 32 mo) the development of OSAS were used in multivariable Cox regression models.

RESULTS

Significant determinants of OSAS assessed by group differences were waist/neck circumference and fibrinogen. Fasting triacylglycerols, systolic blood pressure, and C-reactive protein in men and low sex hormone-binding globulin and elevated homeostatic model assessment in women were further significant covariates. Cox regression analysis for the risk of incident OSAS confirmed the independent predictive value of central obesity measures, especially neck circumference (having a twofold hazard ratio) and younger age. Age-adjusted former smoking status and-compared with the lowest tertile-the upper two tertiles of fibrinogen (relative risk = 1.66, 95% confidence interval: 1.05-2.63) were significant predictors. Elevated triacylglycerols in males and high apolipoprotein B and lowest high-density lipoprotein cholesterol tertile in females also predicted subsequent OSAS. Systolic blood pressure and total cholesterol did not prove to be independent predictors in multivariable adjusted Cox models in which partial sex-dependent independence of obesity measures of the previously stated five variables was essentially retained.

CONCLUSIONS

An enhanced pro-inflammatory state appeared to be the underlying pathophysiologic mechanism for OSAS, whereas in men, the added factor of high-density lipoprotein dysfunction was suggested. Because it contributes to the pro-inflammatory state, discontinuance of smoking was another further significant predictor of OSAS.

Prevalence of sleep apnea and cardiovascular risk factors in patients with hypertension in a day hospital model

INTRODUCTION

To identify patients at risk for obstructive sleep apnea (OSA) syndrome at a specialized hypertension center, we administered questionnaires and used respiratory polygraphy (RP).

RESULTS

We studied 168 patients (64.8% men and 35.2% women). Patients' body mass index (BMI) was 34.7 ± 6.79 and Epworth Sleepiness Scale (ESS) scores were 8.01 for male and 8.92 for women (p = 0.69). RP recordings revealed AHI (Apnea-Hypopnea Index) of 18.03 ± 15.7, an ODI (Oxygen Desaturation Index) of 18.6 ± 15.2, and a time oxygen saturation <90% (%) of 20.8 ± 24.3. Around 44% of patients had an AHI of >15 events/h, and continuous positive airway pressure (CPAP) was recommended to 69 patients (41.07%). Pulse wave velocity (PWV) showed high values in AHI > 15/h (p = 0.050), and carotid intima-media thickness (IMT) did not correlate with AHI > 15; right IMT: 0.83 ± 1.3 versus 0.78 ± 0.13 mm (p = 0.41) and 0.82 ± 0.16 versus 0.78 ± 0.19 mm (p = 0.40). However, we find correlation with carotid plaque (p = 0.046). The ACC/AHA calculator revealed a gradual increase in the risk of cardiovascular events: 8.7% with AHI < 5/h, and 30.3% in severe OSA.

CONCLUSIONS

In hypertension (HT) patients, RP revealed a high prevalence of OSA associated with carotid artery disease, high PWV, and increased cardiovascular risk.

Modest Improvement of Untreated Severe Sleep-Disordered Breathing in the Middle-Aged and Elderly

OBJECTIVE

It has been reported that untreated sleep-disordered breathing (SDB) deteriorates over time, however this remains contentious. The aim of the present study is to evaluate the clinical course of SDB in middle-aged and older SDB patients, and to identify how relevant factors contribute to the change in SDB severity.

METHODS

Baseline and follow-up polysomnographic data of 56 untreated SDB patients (mean age, 61.2±5.71) were obtained retrospectively and the mean interval was 62.4±22.0 months. Subgroup analysis was performed based on the baseline severity, and the factors associated with the course of SDB were analyzed.

RESULTS

At the baseline, 13 subjects were simple snorers, 15 had mild to moderate SDB, and 28 were severe SDB patients. While there was no significant change in apnea-hypopnea index (AHI) as a whole, subgroup analysis showed decrease of AHI in severe SDB patients (43.9±10.6 to 35.6±20.0, p=0.009). The change in supine time percent and baseline AHI were associated with the change in AHI (β=0.387, p=0.003; β=-0.272, p=0.037).

CONCLUSION

Untreated SDB did not deteriorate over time with modest improvement in severe SDB. A proportion of severe SDB patients might expect decrease in SDB severity irrespective of changes in sleep position or body weight.

Cardiac Troponin Values in Patients With Acute Coronary Syndrome and Sleep Apnea: A Pilot Study

BACKGROUND

An analysis of cardiac injury markers in patients with OSA who sustain an episode of acute coronary syndrome (ACS) may contribute to a better understanding of the interactions and impact of OSA in subjects with ACS. We compared peak cardiac troponin I (cTnI) levels in patients with OSA and patients without OSA who were admitted for ACS.

METHODS

Blood samples were collected every 6 hours from the time of admission until two consecutive assays showed a downward trend in the cTnI assay. The highest value obtained defined the peak cTnI value, which provides an estimate of infarct size.

RESULTS

We included 89 patients with OSA and 38 patients without OSA with an apnea-hypopnea index of a median of 32 (interquartile range [IQR], 20.8-46.6/h and 4.8 [IQR, 1.6-9.6]/h, respectively. The peak cTnI value was significantly higher in patients without OSA than in patients with OSA (median, 10.7 ng/mL [IQR, 1.78-40.1 ng/mL] vs 3.79 ng/mL [IQR, 0.37-24.3 ng/mL]; P = .04). The multivariable linear regression analysis of the relationship between peak cTnI value and patient group, age, sex, and type of ACS showed that the presence or absence of OSA significantly contributed to the peak cTnI level, which was 54% lower in patients with OSA than in those without OSA.

CONCLUSIONS

The results of this study suggest that OSA has a protective effect in the context of myocardial infarction and that patients with OSA may experience less severe myocardial injury. The possible role of OSA in cardioprotection should be explored in future studies.