Obstructive sleep apnea: a cardiometabolic risk in obesity and the metabolic syndrome. J Am Coll Cardiol. 2013;62:569-576. [PMID: 23770180 DOI: 10.1016/j.jacc.2013.05.045]

Obstructive Sleep Apnea and Cardiovascular Morbidities: A Review Article

In obstructive sleep apnea (OSA), there are brief episodes of partial or total upper airway obstruction during sleep, which leads to apnea or hypopneas. Much attention is required to understand OSA's effects on the human body, owing to how common but under-diagnosed this disorder remains. Though the role of OSA in cardiovascular (CV) disease is commonly discussed, it remains unclear how it induces changes in the human body. The intermittent and recurrent hypoxia occurring at the cellular level in this condition is critical for the dramatic changes observed. Vascular endothelial cell (VEC) injury and other mechanisms seen in OSA lead to changes in the CV system. OSA can take a toll on a person's overall functioning, especially with so much importance in today's time on preventing and treating cardiac-related deaths. A total of 31 published articles were included from the PubMed database for our literature review. Most of the studies showed a strong association of OSA with hypertension, especially resistant hypertension. Findings were consistent with OSA's independent role in causing CV diseases, included heart failure, coronary artery disease (cardiac ischemia), arrhythmias, and ischemic stroke. Continuous Positive Airway Pressure (CPAP) is one of the reliable and beneficial treatments for OSA patients. OSA is a treatable and modifiable risk factor for cardiac events and related deaths. The primary purpose of our review article was to address any existing gaps between OSA and its effect on the human body with particular emphasis on cardiovascular changes.

HIF-1α as a Mediator of Insulin Resistance, T2DM, and Its Complications: Potential Links With Obstructive Sleep Apnea

Obstructive sleep apnea syndrome (OSA) is described as an independent risk factor for the onset and progression of type 2 diabetes (T2DM), as well as for insulin resistance (IR). The mechanisms underlying these processes remain unclear. One of the proposed molecular mechanism is based on the oxygen-sensitive α-subunit of hypoxia-inducible factor 1 (HIF-1α)-a key regulator of oxygen metabolism. The concept that stabilization of HIF-1α may influence T2DM and IR is supported by cell and animal models. Cell culture studies revealed that both glucose uptake and glycolysis are regulated by HIF-1α. Furthermore, animal models indicated that increased fasting glucose may be caused by a single night with intermittent hypoxia. Moreover, in these models, hypoxia time was correlated with IR. Mice models revealed that inhibition of HIF-1α protein may downregulate fasting blood glucose and plasma insulin level. Administration of superoxide dismutase mimetic resulted in inhibition of HIF-1α protein, catecholamines, and chronic intermittent hypoxia-induced hypertension in a mice model. The hypothesis that hypoxia is an independent risk factor for IR is strengthened by experimentally confirmed improvement of insulin sensitivity among OSA patients treated with the continuous positive airway pressure. Furthermore, recent studies suggest that HIF-1α protein concentration is increased in individuals with OSA. In this literature review, we summarize the current knowledge about HIF-1α in OSA in relation to the possible pathways in which they contribute to metabolic disorders.

COVID-19 and ethnicity: A novel pathophysiological role for inflammation

INTRODUCTION

There have been recent mounting concerns regarding multiple reports stating a significantly elevated relative-risk of COVID-19 mortality amongst the Black and Minority Ethnic (BAME) population. An urgent national enquiry investigating the possible reasons for this phenomenon has been issued in the UK. Inflammation is at the forefront of COVID-19 research as disease severity appears to correlate with pro-inflammatory cytokine dysregulation. This narrative review aims to shed light on the novel, pathophysiological role of inflammation in contributing towards the increased COVID-19 mortality risk amongst the BAME population.

METHODS

Searches in PubMed, Medline, Scopus, medRxiv and Google Scholar were performed to identify articles published in English from inception to 18^th June 2020. These databases were searched using keywords including: 'COVID-19' or 'Black and Minority Ethnic' or 'Inflammation'. A narrative review was synthesized using these included articles.

RESULTS

We suggest a novel pathophysiological mechanism by which acute inflammation from COVID-19 may augment existing chronic inflammation, in order to potentiate a 'cytokine storm' and thus the more severe disease phenotype observed in the BAME population. Obesity, insulin resistance, cardiovascular disease, psychological stress, chronic infections and genetic predispositions are all relevant factors which may be contributing to elevated chronic systemic inflammation amongst the BAME population.

CONCLUSION

Overall, this review provides early insights and directions for ongoing research regarding the pathophysiological mechanisms that may explain the severe COVID-19 disease phenotype observed amongst the BAME population. We suggest 'personalization' of chronic disease management, which can be used with other interventions, in order to tackle this.

Heterozygous SOD2 deletion deteriorated chronic intermittent hypoxia-induced lung inflammation and vascular remodeling through mtROS-NLRP3 signaling pathway

Oxidative stress caused by chronic intermittent hypoxia (CIH) is the hallmark of obstructive sleep apnea (OSA). Among the first line of defense against oxidative stress is the dismutation of superoxide radicals, which in the mitochondria is carried out by manganese superoxide dismutase (SOD2). In this study, wild-type (WT) and SOD2-heterozygous knockout (SOD2^+/−) mice were exposed to CIH or normoxic (Nor) conditions. After 4 weeks, pulmonary artery pressure was measured, and the mice were processed to harvest either serum for cytokine assays or lungs for flow cytometry and histopathological studies. Herein, we showed that heterozygous deletion of SOD2 markedly deteriorated pulmonary remodeling and increased the oxidative stress, especially promoted the infiltration of macrophages in the lungs of CIH mouse. Moreover, in the intermittent hypoxia (IH)-treated RAW264.7 cells, SOD2 knockdown increased the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome activation accompanied with the IL-1β elevation and caspase-1 activity. Additionally, mitochondrial ROS (mtROS) scavenger mito-TEMPO abolished NLRP3 inflammasome activation in IH-treated RAW264.7 cells. Collectively, our results supported that SOD2 contributed to the pathogenesis of CIH-induced lung remodeling. Meanwhile, SOD2 knockdown exacerbates oxidative damage through assembly and activation of NLRP3 inflammasome in macrophages. SOD2 may be a novel therapeutic target for CIH-induced pulmonary inflammation and arteriole remodeling.

Does obstructive sleep apnoea contribute to obesity, hypertension and kidney dysfunction in children? A systematic review protocol

INTRODUCTION

Childhood obstructive sleep apnoea (OSA) is a highly prevalent disorder that may directly contribute to the development of obesity, hypertension and renal injury. Although those associations seem to be clearer in adults, studies in children have revealed conflicting results and updated synthesis of the evidence is lacking. The aim of this systematic review is to summarise the available evidence on the effect of OSA on obesity, systemic blood pressure and kidney function, to help to elucidate whether respiratory interventions to correct OSA would have the potential to improve those outcomes.

METHODS AND ANALYSIS

A systematic literature review search was created by a medical librarian and peer-reviewed by a second librarian prior to running. Ovid Medline, Ovid Embase, CINAHL via EbscoHOST, Wiley Cochrane Library and ProQuest Dissertations and Theses Global were searched on 25 February 2020. Titles and abstracts will be screened by two independent reviewers for inclusion, followed by full-text screening of relevant articles. Studies in children will be included if they report data on OSA and weight, systemic blood pressure or kidney parameters. The extracted data will be combined for analysis and the information subcategorised in groups based on outcome. Risk of bias will be determined using tools specific to study methodology and certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations approach.

ETHICS AND DISSEMINATION

This study will provide essential information for healthcare professionals to better understand the relationship between childhood OSA and changes in body mass index, systemic blood pressure and kidney function indicators. Our findings will be disseminated through conferences and publications. The results of this review may guide the initiation of new strategies and the development of future research studies. This research did not involve human subjects and therefore did not undergo research ethical review.

PROSPERO REGISTRATION NUMBER

CRD42020171186.

Association of C1q/TNF-Related Protein-9 (CTRP9) Level with Obstructive Sleep Apnea in Patients with Coronary Artery Disease

Background

Obstructive sleep apnea (OSA) is closely related to the incidence and progression of coronary artery disease (CAD), and the mechanisms linking OSA and CAD are multifactorial. C1q/TNF-related protein-9 (CTRP9) is a novel adipokine that protects the heart against ischemic injury and ameliorates cardiac remodeling. We aimed to ascertain the clinical relevance of CTRP9 with OSA prevalence in patients with CAD.

Methods

From August 2016 to March 2019, consecutive eligible patients with CAD (n = 154; angina pectoris, n = 88; acute myocardial infarction [AMI], n = 66) underwent cardiorespiratory polygraphy. OSA was defined as an apnea-hypopnea index (AHI) ≥15 events·h^-1. Plasma CTRP9 concentrations were measured by ELISA method.

Results

Moderate/severe OSA was present in 89 patients (57.8%). CTRP9 levels were significantly decreased in the moderate/severe OSA group than in the no/mild OSA group (4.7 [4.1-5.2] ng/mL vs. 4.9 [4.4-6.0] ng/mL, P = 0.003). The difference between groups was only observed in patients with AMI (3.0 [2.3-4.9] vs. 4.5 [3.2-7.9], P = 0.009). Correlation analysis showed that CTRP9 levels were negatively correlated with AHI (r = -0.238, P = 0.003) and oxygen desaturation index (r = -0.234, P = 0.004) and positively correlated with left ventricular ejection fraction (r = 0.251, P = 0.004) in all subjects. Multivariate analysis showed that male gender (OR 3.099, 95% CI 1.029-9.330, P = 0.044), BMI (OR 1.148, 95% CI 1.040-1.268, P = 0.006), and CTRP9 levels (OR 0.726, 95% CI 0.592-0.890, P = 0.002) were independently associated with the prevalence of moderate/severe OSA.

Conclusions

Plasma CTRP9 levels were independently related to the prevalence of moderate/severe OSA in patients with CAD, suggesting that CTRP9 might play a role in the pathogenesis of CAD exacerbated by OSA.

Carotid Body and Metabolic Syndrome: Mechanisms and Potential Therapeutic Targets

The carotid body (CB) is responsible for the peripheral chemoreflex by sensing blood gases and pH. The CB also appears to act as a peripheral sensor of metabolites and hormones, regulating the metabolism. CB malfunction induces aberrant chemosensory responses that culminate in the tonic overactivation of the sympathetic nervous system. The sympatho-excitation evoked by CB may contribute to the pathogenesis of metabolic syndrome, inducing systemic hypertension, insulin resistance and sleep-disordered breathing. Several molecular pathways are involved in the modulation of CB activity, and their pharmacological manipulation may lead to overall benefits for cardiometabolic diseases. In this review, we will discuss the role of the CB in the regulation of metabolism and in the pathogenesis of the metabolic dysfunction induced by CB overactivity. We will also explore the potential pharmacological targets in the CB for the treatment of metabolic syndrome.

Cell-Autonomous Autophagy Protects Against Chronic Intermittent Hypoxia Induced Sensory Nerves and Endothelial Dysfunction of the Soft Palate

BACKGROUND Chronic intermittent hypoxia (CIH) is a key feature of obstructive sleep apnea (OSA) syndrome. The pathogenesis of CIH-induced soft palate lesion is not well understood. Understanding the mechanisms of CIH-induced soft palate damage could provide new strategies for clinical treatment. MATERIAL AND METHODS Twenty male Sprague‑Dawley rats were randomized into a control group (n=10) and experimental group (n=10). The experimental group were exposed to CIH for 28 days. The control experiments were run in parallel. Morphological changes of CIH-induced soft palate were examined by hematoxylin and eosin. Peripheral nerves and vascular associated markers were analyzed by western blot and immunohistochemical staining. LC3B expression and transmission electron microscopy analysis was detected to investigate the destiny of cells in CIH-induced soft palate. RESULTS Histological studies demonstrated the thicken mucosal layer, muscular changes consistent with glands hyperplasia, and loose connective tissues of the soft palate in CIH induced rat models. CIH exposure significantly decreased the expression of annexin V but did not change argin level, suggesting that sensory nerves not motor nerves were damaged when exposed to intermittent hypoxia. Moreover, in response to CIH, the vascular vessel around the nerves and muscles became enlarged and caveolin-1 was overexpressed. Autophagy occurs in response to CIH-induced neuromuscular and vascular endothelial injury. CONCLUSIONS Sensory nerves and endothelial dysfunction contributed to the morphological damage of soft palate under intermittent hypoxia. Autophagy as a compensatory mechanism protects against CIH-induced injury. These findings have important implications for understanding mechanisms contributing to the increased soft palate lesion in patients with OSA.

Correlation between Obstructive Sleep Apnea and Non-Alcoholic Fatty Liver Disease before and after Metabolic Bariatric Surgery

BACKGROUND

Emerging evidence has revealed that obstructive sleep apnea (OSA) is associated with non-alcoholic fatty liver disease (NAFLD). However, the impact of OSA on NAFLD among obese patients undergoing metabolic and bariatric surgery (MBS), especially during follow-up period, remains unclear.

OBJECTIVE

To analyze the correlation based on preoperative characteristics and postoperative conditions among bariatric patients with comorbid OSA and NAFLD.

METHODS

Clinical data of patients who underwent MBS in our institution between January 2016 and June 2019 were reviewed retrospectively. Correlation analysis and linear regressions were used to identify how OSA links with NAFLD before and after treatment of MBS.

RESULTS

Of 308 patients, 181 were diagnosed with OSA and enrolled in the present study, and 127 completed follow-up visits at 6 months. The proportion of NAFLD in the mild-moderate OSA and severe OSA groups was 75.0% and 96.0%, respectively. MBS was effective at improving sleep apnea and nocturnal hypoxia, as well as liver steatosis and fibrosis (P < 0.05). And we also found that there were significant correlations not only between OSA- and NAFLD-related characteristics at baseline but also between their improvements after surgery, eventually leading to similar prognosis of NAFLD for both groups (P < 0.05), no matter what presurgical differences existed. In addition, the results of the univariate and multivariate linear regression analyses supported preoperative liver/spleen Hounsfield units ratio (LSR) by computerized tomography (CT) as an independent predictor of the effect of MBS on liver steatosis.

CONCLUSION

In conclusion, MBS plays a pivotal role in the control of medical conditions in obese patients with OSA and NAFLD. Given the correlation between OSA and NAFLD in the present study, in the case of both the severity at baseline as well as the improvement after surgery, OSA may pose an impact on the prognosis of NAFLD in bariatric patients.

Serum and Plasma Tumor Necrosis Factor Alpha Levels in Individuals with Obstructive Sleep Apnea Syndrome: A Meta-Analysis and Meta-Regression

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is associated with a variety of inflammatory factors. Specifically, proinflammatory cytokines appear to be associated with the pathogenesis of OSAS.

METHODS

For the present meta-analysis and meta-regression on serum and plasma tumor necrosis factor alpha (TNF-α) levels in individuals with and without OSAS, we performed a systematic search without any restrictions of the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases to find relevant articles published up to February 1, 2020.

RESULTS

Fifty-five (adults: 29 studies on serum and 17 studies on plasma; children: 4 studies on serum and 5 studies on plasma) were included and analyzed. Always compared to age-matched healthy controls, the pooled MDs were as follows: adults, serum: 10.22 pg/mL (95% CI = 8.86, 11.58; p < 0.00001); adults, plasma: 5.90 pg/mL (95% CI = 4.00, 7.80; p < 0.00001); children, serum: 0.21 pg/mL (95% CI = 0.05, 0.37; p = 0.01); children, plasma: 5.90 pg/mL (95% CI = 4.00, 7.80; p < 0.00001).

CONCLUSIONS

Compared to healthy and age-matched controls, adult individuals with OSAS had significantly higher serum/plasma TNF-α levels. For children with OSAS, significantly higher levels were observed for TNF-α in serum but not in plasma.

Primary Aldosteronism and Obstructive Sleep Apnea: Casual Association or Pathophysiological Link?

The coexistence of aldosterone oversecretion and obstructive sleep apnea is frequently observed, especially in patients with resistant hypertension, obesity, and metabolic syndrome. Since aldosterone excess and sleep apnea are both independently associated with an increased risk of cardiovascular disease, to investigate whether their coexistence might be attributed to common predisposing conditions, such as metabolic disorders, or to an actual pathophysiological interconnection appears of great importance. Fluid overload and metabolic abnormalities relating to aldosterone oversecretion may be implicated in obstructive sleep apnea development. Nocturnal intermittent hypoxia may in turn exacerbate renin-angiotensin-aldosterone system activity, thus leading to hyperaldosteronism. Furthermore, fat tissue excess and adipocyte secretory products might predispose to both sleep apnea and aldosterone oversecretion in subjects with obesity. Consistent with these evidences, obstructive sleep apnea frequently affects patients with primary aldosteronism. Conversely, whether primary aldosteronism is more prevalent in individuals affected by obstructive sleep apnea compared to the general population remains controversial.

Association between non-alcoholic fatty liver disease and obstructive sleep apnea

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging liver disease and currently the most common cause of incidental abnormal liver tests. The pathogenesis of NAFLD is multifactorial and many mechanisms that cause fatty liver infiltration, inflammation, oxidative stress and progressive fibrosis have been proposed. Obstructive sleep apnea (OSA) may be linked with the pathogenesis and the severity of NAFLD.

AIM

To study the association between NAFLD and OSA considering also the efficacy of continuous positive airway pressure (CPAP) treatment.

METHODS

A PubMed search was conducted using the terms “non-alcoholic fatty liver disease AND (obstructive sleep apnea OR obstructive sleep disorders OR sleep apnea)”. Research was limited to title/abstract of articles published in English in the last 5 years; animal and child studies, case reports, commentaries, letters, editorials and meeting abstracts were not considered. Data were extracted on a standardized data collection table which included: First author, publication year, country, study design, number of patients involved, diagnosis and severity of OSA, diagnosis of NAFLD, patient characteristics, results of the study.

RESULTS

In total, 132 articles were initially retrieved on PubMed search and 77 in the last five years. After removal of irrelevant studies, 13 articles were included in the qualitative analysis. There was a total of 2753 participants across all the studies with a mean age between 42 and 58 years. The proportion of males ranged from 21% to 87.9% and the mean body mass index ranged from 24.0 to 49.9 kg/m². The results of this review showed an increased prevalence of NAFLD in patients with diagnosis of OSA, even in the absence of coexisting comorbidities such as obesity or metabolic syndrome. Furthermore, the severity of NAFLD is associated with the increase in OSA severity. Effective CPAP treatment, although not always decisive, may stabilize or slow NAFLD progression with benefits on metabolic and cardiovascular functions.

CONCLUSION

In NAFLD patients, although asymptomatic, it is recommended to systematically perform polysomnography in order to early and better treat them before the development of potentially life threatening systemic dysfunctions.

Body mass index across adult life and cognitive function in the American elderly

This study aimed to examine the associations of body mass index (BMI) across adult life with cognitive function in 2,637 participants aged 60 years or over from NHANES 2011-2014. The primary outcome was a composite score based on test scores on word list learning, animal naming, and digit symbol substitution. Exposures of interest included BMI at age 25, BMI 10 years before the survey, BMI at the survey (current BMI), and BMI burden calculated from age 25 to age at survey. BMI at age 25 was inversely associated with the composite score (β=-0.0271±0.0130 per kg/m², P=0.038) and positively with low cognitive performance (odd ratio=1.04, 95% confidence interval: 1.01-1.07, P=0.010), defined as below 20 percentile of the composite score. Similar results were observed for BMI 10 years before the survey and BMI burden. Current BMI was positively associated with the composite score (β=0.0369±0.0113, P=0.001) and inversely associated with low cognitive performance (odd ratio=0.96, 95% confidence interval: 0.94-0.99, P=0.004). In conclusion, high BMI in early adult life is associated with low cognitive function in late life, which underscores the importance of a healthy body weight across the life course. The association between BMI and cognitive function at late life requires further investigation.

Sleep disordered breathing and metabolic comorbidities across sex and menopausal status in East Asians: the Nagahama Study

It is well known that the prevalence of sleep disordered breathing (SDB) is increased in patients with obesity or metabolic comorbidities. However, the way in which the prevalence of SDB increases in relation to comorbidities according to the severity of obesity remains unclear.

This cross-sectional study evaluated 7713 community participants using nocturnal oximetry ≥2 nights. SDB was assessed by the 3% oxygen desaturation index corrected for sleep duration obtained by wrist actigraphy (acti-ODI3%). SDB severity was defined by acti-ODI3%. Obesity was defined as body mass index ≥25 kg·m−2.

The prevalence of SDB was 41.0% (95% CI 39.9–42.1%), 46.9% (45.8–48.0%), 10.1% (9.5–10.8%) and 2.0% (1.7–2.3%) in normal, mild, moderate and severe SDB, respectively, with notable sex differences evident (males>post-menopausal females>premenopausal females). Comorbidities such as hypertension, diabetes and metabolic syndrome were independently associated with the prevalence of moderate-to-severe SDB, and coincidence of any one of these with obesity was associated with a higher probability of moderate-to-severe SDB (hypertension OR 8.2, 95% CI 6.6–10.2; diabetes OR 7.8, 95% CI 5.6–10.9; metabolic syndrome OR 6.7, 95% CI 5.2–8.6). Dyslipidaemia in addition to obesity was not additively associated with the prevalence of moderate-to-severe SDB. The number of antihypertensive drugs was associated with SDB (p for trend <0.001). Proportion of a high cumulative percentage of sleep time with oxygen saturation measured by pulse oximetry <90% increased, even among moderate-to-severe SDB with increases in obesity.

Metabolic comorbidities contribute to SDB regardless of the degree of obesity. We should recognise the extremely high prevalence of moderate-to-severe SDB in patients with obesity and metabolic comorbidities.

Advances and challenges in pursuing biomarkers for obstructive sleep apnea: Implications for the cardiovascular risk

Obstructive sleep apnea (OSA) is a common clinical condition associated with increased cardiovascular morbidity and mortality. Recent evidence from clinical studies and animal models suggest that OSA can promote cardiovascular disease by inducing autonomic, hemodynamic, inflammatory and metabolic dysregulation. However, most of the evidence addressing hard endpoints in humans is derived from observational studies. Several challenges have been noted in the pursuit of a comprehensive knowledge base about the impact of OSA including: 1) the precise mechanisms by which OSA causes metabolic and cardiovascular consequences are not clear, which limits our current ability to address potential targets in OSA; 2) several patients with OSA, even with severe forms, present with no or mild daytime symptoms. Beyond the obvious challenges for obtaining good adherence for conventional OSA treatments, there is evidence that symptomatic vs. asymptomatic patients with OSA do not necessarily have the same metabolic and cardiovascular outcomes; and 3) the cardiovascular response to OSA treatment may vary even in those patients with good adherence. In this scenario, there is an obvious need to develop biomarkers in the OSA research area. This review focuses on describing the advances that have occurred so far in exploring potential OSA biomarkers with clear emphasis for the cardiovascular risk. Particular attention will be devoted to discuss molecular biomarkers including the potential role of microRNAs, proteomics and metabolomics. We also discuss the major challenges and perspectives in this growing research field.

Pre-diabetic patients with severe obstructive sleep apnea: novel parameters of hypoxia during sleep correlate with insulin resistance

Obstructive sleep apnea (OSA) is an increasingly prevalent sleep disorder with estimated prevalence of moderate to severe sleep apnea ranging between 6-13% in the adult population. Nocturnal intermittent hypoxia has been associated with an increased risk of developing type 2 diabetes and insulin resistance (IR). The existing indices of hypoxia, used in polysomnography (PSG), cannot express accurately the influence of the mild desaturations precisely during sleep. In the present study, 73 subjects without other comorbidities were examined by PSG. Hypoxia parameters were analyzed, in the intervals with low values of SpO₂ signal. The thresholds were set at 94% and 92% and the average value (M) of the SpO₂ signal, in areas below thresholds, were calculated. The desaturations were analyzed together with their duration within the recording in terms of SpO₂ signal parameters. Blood samples were taken for biochemical analysis. A total of 50 subjects were diagnosed with OSAS with mean AHI of 56.11±27.70/h and 23 subjects had no sleep apnea with mean AHI of 3.47±0.6/h. The amount of desaturations was significantly correlated with insulin levels (r=0.301, p=0.034) and the percentage of desaturation events (Dev) that were longer than 6 points (2 sec) (r=0.301, p=0.034). In addition, mean duration of desaturations was significantly correlated with IR as expressed by HOMA index (r=0.289, p=0.047), as well as with total duration of desaturation of SpO₂ (r=0.322, p =0.025) and percentage of Dev that were long than 6 points (2 sec) (r=0.292, p=0.044). A strong correlation was also revealed between total duration of desaturations and fasting glucose (r=0.887, p=0.000). Results suggest that hypoxia parameters derived from SpO₂ signal analysis, are strongly correlated with IR and fasting glucose levels, implying a role of hypoxia in the pathogenesis of diabetes.

Obstructive Sleep Apnea: A View from the Back Door

Obstructive sleep apnea (OSA) is a common disease that may affect up to 50% of the adult population and whose incidence continues to rise, as well as its health and socio-economic burden. OSA is a well-known risk factor for motor vehicles accidents and decline in work performance and it is frequently accompanied by cardiovascular diseases. The aim of this Special Issue is to focus on the characteristics of OSA in special populations which are less frequently investigated. In this regard, seven groups of experts in the field of sleep medicine gave their contribution in the realization of noteworthy manuscripts which will support all physicians in improving their understanding of OSA with the latest knowledge about its epidemiology, pathophysiology and comorbidities in special populations, which will serve as a basis for future research.

Efficacy of continuous positive airway pressure on subcutaneous adipose tissue in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

PURPOSE

It remains inconclusive whether continuous positive airway pressure (CPAP) therapy can significantly reduce subcutaneous adipose tissue (SAT) in patients with obstructive sleep apnea (OSA). This meta-analysis of randomized controlled trials (RCTs) aimed to evaluate the impact of CPAP treatment on SAT in patients with OSA.

METHODS

We searched Pubmed, Cochrane, Web of Science, and Embase for RCTs, which investigated the effectiveness of CPAP treatment in reducing SAT among patients with OSA. Following the PRISMA guidelines, we extracted information on the study and patient characteristics, and pre- and post-CPAP measures of SAT. We then calculated the overall effects using the standardized mean difference (SMD) with a 95% confidence interval (CI).

RESULTS

A total of 5 RCTs (comprising 153 patients) met inclusion criteria for the meta-analysis. We found that the SAT did not change before and after CPAP treatment in patients with OSA (SMD = - 0.02, 95% CI - 0.25 to 0.2, z = 0.19, p = 0.85). Subgroup analyses indicated that the outcome was not affected by age, CPAP therapy duration, baseline body mass index, and measure utilized.

CONCLUSION

This meta-analysis of RCTs suggests that CPAP therapy does not significantly decrease the level of SAT among patients with OSA. Further large-scale, and high-quality randomized controlled trials are needed to better address this issue.

Modifiable Cardiovascular Risk, Hematopoiesis, and Innate Immunity

Unhealthy diet, lack of exercise, psychosocial stress, and insufficient sleep are increasingly prevalent modifiable risk factors for cardiovascular disease. Accumulating evidence indicates that these risk factors may fuel chronic inflammatory processes that are active in atherosclerosis and lead to myocardial infarction and stroke. In concert with hyperlipidemia, maladaptive immune system activities can contribute to disease progression and increase the probability of adverse events. In this review, we discuss recent insight into how the above modifiable risk factors influence innate immunity. Specifically, we focus on pathways that raise systemic myeloid cell numbers and modulate immune cell phenotypes, reviewing hematopoiesis, leukocyte trafficking, and innate immune cell accumulation in cardiovascular organs. Often, relevant mechanisms that begin with lifestyle choices and lead to cardiovascular events span multiple organ systems, including the central nervous, endocrine, metabolic, hematopoietic, immune and, finally, the cardiovascular system. We argue that deciphering such pathways provides not only support for preventive interventions but also opportunities to develop biomimetic immunomodulatory therapeutics that mitigate cardiovascular inflammation.

Effectiveness of an intensive weight-loss program for severe OSA in patients undergoing CPAP treatment: a randomized controlled trial

STUDY OBJECTIVES

To determine whether an intensive weight-loss program (IWLP) is effective for reducing weight, the severity of obstructive sleep apnea (OSA), and metabolic variables in patients with obesity and severe OSA undergoing continuous positive airway pressure treatment.

METHODS

Forty-two patients were randomized to the control (CG, n = 20) or the intervention group (IG, n = 22), who followed a 12-month IWLP. The primary outcome was a reduction in the apnea-hypopnea index (AHI) as measured at 3 and 12 months by full polysomnography. Metabolic variables, blood pressure, body fat composition by bioimpedance, carotid intima media thickness, and visceral fat by computed tomography were also assessed.

RESULTS

Mean age was 49 (6.7) years, body mass index 35 (2.7) kg/m², and AHI 69 (20) events/h. Weight reduction was higher for the IG than the CG at 3 and 12 months, -10.5 versus -2.3 kg (P < .001), and -8.2 versus -0.1 kg (P < .001), respectively, as was loss of visceral fat at 12 months. AHI decreased more in the IG at 3 months (-23.72 versus -9 events/h) but the difference was not significant at 12 months, though 28% of patients from the IG had an AHI < 30 events/h compared to none in the CG (P = .046). At 12 months, the IG showed a reduction in C-reactive protein (P = .013), glycated hemoglobin (P = .031) and an increase in high density lipoprotein cholesterol (P = .027).

CONCLUSIONS

An IWLP in patients with obesity and severe OSA is effective for reducing weight and OSA severity. It also results in an improvement in lipid profiles, glycemic control, and inflammatory markers.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Effectiveness of an Intensive Weight Loss Program for Obstructive Sleep Apnea Syndrome (OSAS) Treatment; Identifier: NCT02832414; URL: https://clinicaltrials.gov/ct2/show/record/NCT02832414.

Validation of fatty liver index and hepatic steatosis index for screening of non-alcoholic fatty liver disease in adults with obstructive sleep apnea hypopnea syndrome

Background:

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a contributing factor for non-alcoholic fatty liver disease (NAFLD). Non-invasive algorithms including fatty liver index (FLI) and hepatic steatosis index (HSI) have been used as a screening test for NAFLD in epidemiologic studies. The aim of this study is to compare the diagnostic accuracy of FLI and HSI for NAFLD detection in adults with OSAHS.

Methods:

We enrolled consecutive adult subjects who were newly diagnosed with OSAHS from March 2016 to January 2018. NAFLD was diagnosed by ultrasonography. The accuracy and cut-off point of the FLI and HSI to detect NAFLD were assessed by analyzing the area under the receiver operating characteristic (AUROC) curve and the maximum Youden index analysis, respectively.

Results:

The 326 subjects were diagnosed as NAFLD according to ultrasound findings, while 105 subjects who had normal abdominal ultrasonography were grouped as controls. Both FLI and HSI values were significantly higher in patients with NAFLD compared with controls. The AUROC of FLI and HSI for predicting NAFLD was 0.802 (95% confidence interval [CI] 0.762–0.839) and 0.753 (95% CI 0.710–0.793), respectively. The AUROC of FLI was significantly higher than that of HSI (P = 0.0383). The optimal cut-off value of FLI and HSI was 60 (sensitivity 66% and specificity 80%) and 35 (sensitivity 81% and specificity 60%), respectively.

Conclusions:

Both FLI and HSI can serve as screening tools for NAFLD in OSAHS adults. The FLI shows better performance in diagnosing NAFLD than HSI.

Trial registration:

Chinese Clinical Trial Registry (No. ChiCTR-OOB-15007253), http://www.chictr.org.cn/showproj.aspx?proj=11606.

Sleep-disordered breathing in adolescents with obesity: When does it start to affect cardiometabolic health?

BACKGROUND AND AIMS

Pediatric obesity and sleep-disordered breathing (SDB) are associated with cardiometabolic risk (CMR), but the degree of severity at which SDB affects cardiometabolic health is unknown. We assessed the relationship between the CMR and the apnea-hypopnea index (AHI), to identify a threshold of AHI from which an increase in the CMR is observed, in adolescents with obesity. We also compared the clinical, cardiometabolic and sleep characteristics between adolescents presenting a high (CMR+) and low CMR (CMR-), according to the threshold of AHI.

METHODS AND RESULTS

114 adolescents with obesity were recruited from three institutions specialized in obesity management. Sleep and SDB as assessed by polysomnography, anthropometric parameters, fat mass (FM), glucose and lipid profiles, and blood pressure (BP) were measured at admission. Continuous (MetScore_FM) and dichotomous (metabolic syndrome, MetS) CMR were determined. Associations between MetScore_FM and AHI adjusted for BMI, sex and age were assessed by multivariable analyses. Data of 82 adolescents were analyzed. Multivariable analyses enabled us to identify a threshold of AHI = 2 above which we observed a strong and significant association between CMR and AHI (Cohen's d effect-size = 0.57 [0.11; 1.02] p = 0.02). Adolescents with CMR+ exhibited higher MetScore_FM (p < 0.05), insulin resistance (p < 0.05), systolic BP (p < 0.001), sleep fragmentation (p < 0.01) and intermittent hypoxia than CMR- group (p < 0.0001). MetS was found in 90.9% of adolescents with CMR+, versus 69.4% in the CMR- group (p < 0.05).

CONCLUSIONS

The identification of a threshold of AHI ≥ 2 corresponding to the cardiometabolic alterations highlights the need for the early management of SDB and obesity in adolescents, to prevent cardiometabolic diseases.

CLINICAL TRIALS

NCT03466359, NCT02588469 and NCT01358773.

Upper airway collapsibility measured using a simple wakefulness test closely relates to the pharyngeal critical closing pressure during sleep in obstructive sleep apnea

STUDY OBJECTIVES

A collapsible or crowded pharyngeal airway is the main cause of obstructive sleep apnea (OSA). However, quantification of airway collapsibility during sleep (Pcrit) is not clinically feasible. The primary aim of this study was to compare upper airway collapsibility using a simple wakefulness test with Pcrit during sleep.

METHODS

Participants with OSA were instrumented with a nasal mask, pneumotachograph and two pressure sensors, one at the choanae (PCHO), the other just above the epiglottis (PEPI). Approximately 60 brief (250 ms) pulses of negative airway pressure (~ -12 cmH2O at the mask) were delivered in early inspiration during wakefulness to measure the upper airway collapsibility index (UACI). Transient reductions in the continuous positive airway pressure (CPAP) holding pressure were then performed during sleep to determine Pcrit. In a subset of participants, the optimal number of replicate trials required to calculate the UACI was assessed.

RESULTS

The UACI (39 ± 24 mean ± SD; range = 0%-87%) and Pcrit (-0.11 ± 2.5; range: -4 to +5 cmH2O) were quantified in 34 middle-aged people (9 female) with varying OSA severity (apnea-hypopnea index range = 5-92 events/h). The UACI at a mask pressure of approximately -12 cmH2O positively correlated with Pcrit (r = 0.8; p < 0.001) and could be quantified reliably with as few as 10 replicate trials. The UACI performed well at discriminating individuals with subatmospheric Pcrit values [receiver operating characteristic curve analysis area under the curve = 0.9 (0.8-1), p < 0.001].

CONCLUSIONS

These findings indicate that a simple wakefulness test may be useful to estimate the extent of upper airway anatomical impairment during sleep in people with OSA to direct targeted non-CPAP therapies for OSA.

Effect of Glucose Improvement on Nocturnal Sleep Breathing Parameters in Patients with Type 2 Diabetes: The Candy Dreams Study

Type 2 diabetes exerts a negative impact on sleep breathing. It is unknown whether a long-term improvement in glycemic control ameliorates this effect. We conducted an interventional study with 35 patients with type 2 diabetes and obstructive sleep apnea (OSA) to explore this. At home, sleep breathing parameters were assessed at baseline and after a 4-month period in which antidiabetic therapy was intensified. Patients who decreased their body mass index ≥2kg/m² were excluded. Those with an HbA1c reduction ≥0.5% were considered good responders (n = 24). After the follow-up, good responders exhibited an improvement in the apnea–hypopnea index (AHI: 26-1 (95% IC: 8.6–95.0) vs. 20.0 (4.0–62.4) events/hour, p = 0.002) and in time with oxygen saturation below 90% (CT90: 13.3 (0.4–69.0) vs. 8.1 (0.4–71.2) %, p = 0.002). No changes were observed in the group of non–responders (p = 0.722 and p = 0.138, respectively). The percentage of moderate and severe OSA decreased among good responders (p = 0.040). In the wider population, the change in HbA1c correlated positively to decreases in AHI (r = 0.358, p = 0.035) and negatively to increases in the minimum arterial oxygen saturation (r = −0.386, p = 0.039). Stepwise multivariate regression analysis showed that baseline AHI and the absolute change in HbA1c independently predicted decreased AHI (R² = 0.496). The improvement of glycemic control exerts beneficial effects on sleep breathing parameters in type 2 diabetes, which cannot be attributed merely to weight loss.

The relationship of hypertension with obesity and obstructive sleep apnea in adolescents

OBJECTIVES

To assess the independent relationships of obesity and obstructive sleep apnea (OSA) with hypertension/elevated blood pressure (EBP) in adolescent patients.

STUDY DESIGN

A retrospective cohort analysis was performed on 501 patients (age 13-21 years) with three separate blood pressure measurements within 6 months of polysomnography. EBP was defined as average systolic blood pressure (SBP) ≤120 mm Hg; obesity as body mass index Z-score ≤1.65; and OSA as obstructive apnea-hypopnea index <1. Pearson correlations and multivariable analyses were performed to assess the independent effects of the apnea-hypopnea index and body mass index Z-score on SBP.

RESULTS

Of 501 patients (mean age 16 ± 2 years), 246 (49%) were male. OSA was present in 329 (66%) patients, obesity in 337 (67%), and EBP in 262 (52%). EBP was present in 70% of obese adolescents and 60% of adolescents with OSA. Univariable correlation showed a significant relationship between SBP, body mass index Z-score, and apnea-hypopnea index. Multivariable linear regression analysis showed blood pressure was significantly associated with body mass index Z-score (β = .46; P < .01), age (β = .25; P < .01), and height Z-score (β = .14; P < .01), but not apnea-hypopnea index (β = .01; P = .72).

CONCLUSIONS

The relationship between OSA and EBP in adolescents is most closely associated with the degree of obesity. Further studies are needed to assess the effect of the treatment of obesity and OSA on blood pressure in adolescents.

Evaluation and Management of Children with Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a common pediatric disorder characterized by recurrent events of partial or complete upper airway obstruction during sleep which result in abnormal ventilation and sleep pattern. OSAS in children is associated with neurobehavioral deficits and cardiovascular morbidity which highlights the need for prompt recognition, diagnosis, and treatment. The purpose of this state-of-the-art review is to provide an update on the evaluation and management of children with OSAS with emphasis on children with complex medical comorbidities and those with residual OSAS following first-line treatment. Proposed treatment strategies reflecting recommendations from a variety of professional societies are presented. All children should be screened for OSAS and those with typical symptoms (e.g., snoring, restless sleep, and daytime hyperactivity) or risk factors (e.g., neurologic, genetic, and craniofacial disorders) should undergo further evaluation including referral to a sleep specialist or pediatric otolaryngologist and overnight polysomnography, which provides a definitive diagnosis. A cardiology and/or endocrinology evaluation should be considered in high-risk children. For the majority of children, first-line treatment is tonsillectomy with or without adenoidectomy; however, some children exhibit multiple levels of airway obstruction and may require additional evaluation and management. Anti-inflammatory medications, weight loss, and oral appliances may be appropriate in select cases, particularly for mild OSAS. Following initial treatment, all children should be monitored for residual symptoms and polysomnography may be repeated to identify persistent disease, which can be managed with positive airway pressure ventilation and additional surgical approaches if required.

Non-contact diagnosis of obstructive sleep apnea using impulse-radio ultra-wideband radar

While full-night polysomnography is the gold standard for the diagnosis of obstructive sleep apnea, its limitations include a high cost and first-night effects. This study developed an algorithm for the detection of respiratory events based on impulse-radio ultra-wideband radar and verified its feasibility for the diagnosis of obstructive sleep apnea. A total of 94 subjects were enrolled in this study (23 controls and 24, 14, and 33 with mild, moderate, and severe obstructive sleep apnea, respectively). Abnormal breathing detected by impulse-radio ultra-wideband radar was defined as a drop in the peak radar signal by ≥30% from that in the pre-event baseline. We compared the abnormal breathing index obtained from impulse-radio ultra-wideband radar and apnea–hypopnea index (AHI) measured from polysomnography. There was an excellent agreement between the Abnormal Breathing Index and AHI (intraclass correlation coefficient = 0.927). The overall agreements of the impulse-radio ultra-wideband radar were 0.93 for Model 1 (AHI ≥ 5), 0.91 for Model 2 (AHI ≥ 15), and 1 for Model 3 (AHI ≥ 30). Impulse-radio ultra-wideband radar accurately detected respiratory events (apneas and hypopneas) during sleep without subject contact. Therefore, impulse-radio ultra-wideband radar may be used as a screening tool for obstructive sleep apnea.

Impact of Diabetes on the Symptoms of Breast Cancer Survivors

OBJECTIVES

To examine the impact of diabetes on the symptoms of women with breast cancer.

SAMPLE & SETTING

121 women with breast cancer who self-identified as having a diabetes diagnosis and 1,006 women with breast cancer without diabetes from 97 sites across the United States.

METHODS & VARIABLES

Symptom scores for depression, anxiety, sexual function, peripheral neuropathy, physical function, attention function, sleep disturbance, and fatigue were compared between women with breast cancer and diabetes and women with breast cancer without diabetes, controlling for age, education, income, marital status, and body mass index (BMI).

RESULTS

Women with breast cancer and diabetes who were three to eight years postdiagnosis reported poorer physical and attention function, more sleep disturbance, and greater fatigue than women with breast cancer without diabetes. Age, education, income, and BMI were independent predictors of symptoms experienced by women with breast cancer.

IMPLICATIONS FOR NURSING

Oncology nurses can assess and monitor women with breast cancer and diabetes for increased post-treatment sequelae. If problematic symptoms are identified, implementing treatment plans can decrease symptom burden and increase quality of life for women with breast cancer and diabetes.

Aortic morphology post type A acute aortic syndrome: Prognosis significance and association with 24-hour blood pressure-monitoring parameters

BACKGROUND

After an emergent surgery for type A acute aortic syndrome, medical management is based on optimal blood pressure (BP) control. We assessed the prognostic significance of BP monitoring and its relationship with aortic morphology following type A acute aortic syndrome.

METHODS

The data of 120 patients who underwent BP monitoring after a type A acute aortic syndrome from January 2005 to June 2016 were retrospectively collected. The first CT angiogram performed after surgery was used for the morphological analysis.

RESULTS

The population included 79 males, with an overall mean age of 60 ± 12 years. Seven patients (5.8%) died during a median follow-up of 5.5 years. The median delay between BP monitoring and discharge was 3 (1-5) months. The mean 24-hour BP of the cohort was 127/73 mm Hg ± 10/17. During follow-up, different parameters of BP monitoring were not associated with the risk of aortic events. However, the diameter of the false lumen of the descending thoracic aorta was the best predictor associated with the risk of new aortic events during follow-up, particularly for the threshold of 28 mm or more (P < .001; Hazard ratio 4.7[2.7-8.2]). The diameter of the false lumen was associated with night-time systolic BP (P = .025; r = .2), 24-hour pulse pressure (P = .002; r = .28), and night-time pulse pressure (P = .008; r = .24).

CONCLUSION

The risk of new aortic events following type A acute aortic syndrome is associated with the size of the residual false lumen, but not directly with BP parameters. Night-time BP parameters are associated with the size of the residual false lumen.

Lifestyle Interventions Beyond Diet and Exercise for Patients With Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a growing worldwide concern, affecting approximately 30% of the US adult population. Developing pharmacologic therapies for NAFLD is crucial, especially as there are currently no treatments approved by the US Food and Drug Administration. However, weight loss remains the cornerstone of treatment and has been shown in controlled trials to improve hepatic steatosis, hepatic inflammation, and fibrosis. Healthy diet and exercise are the most well-known and frequently recommended lifestyle modifications for patients with NAFLD. This article presents the data on other aspects of healthy lifestyle modifications for patients with this condition, focusing on light alcohol consumption, coffee, circadian misalignments, and sleep.

Knowledge, attitude, and practice regarding obstructive sleep apnea among primary care physicians

PURPOSE

Obstructive sleep apnea (OSA) has been linked with inflammation, hypertension, and higher cardiovascular risk which cause substantial morbidity and mortality worldwide. However, OSA is underdiagnosed and its prevalence is increasing. Primary care doctors are the first contact for most patients and primary care providers play an important role in promoting, screening, and educating patients regarding OSA. This study aims to determine the knowledge, attitudes, and practices regarding OSA among primary care doctors in Kuala Lumpur, Malaysia.

METHODS

A cross-sectional survey was conducted among physicians who were currently working in primary care clinics in the capital state of Kuala Lumpur. The validated "Obstructive Sleep Apnea Knowledge and Attitudes Questionnaire" (OSAKA) and nine additional practice questions were used as the survey instrument.

RESULTS

Of 207 physicians queried, the response rate was 100%. The mean (± SD) total knowledge score was 11.6 (± 2.8) (range 1-18). The majority of respondents had a positive attitude towards the importance of OSA but lacked confidence in managing OSA. Primary care doctors' most common practice for patients with suspected OSA was referral to the ear, nose, and throat (ENT) clinic.

CONCLUSIONS

The study shows that primary care doctors demonstrated adequate knowledge about OSA and were aware of the importance of OSA as a core clinical problem. However, only a minority felt confident in managing patients with OSA. The results of the study may encourage improvement of primary care doctors' efforts to prevent and manage OSA.

Evaluation of the left atrial function by two-dimensional speckle-tracking echocardiography in diabetic patients with obesity

Obesity and diabetes are risk factors for atrial cardiomyopathy and are, thus, deemed public health concerns. However, the effects of obesity on the left atrial (LA) function in patients with diabetes have not been determined yet. We sought to evaluate the effects of obesity on the LA function in patients with type 2 diabetes. Ninety-six consecutive patients with type 2 diabetes without significant coronary artery stenosis in selective coronary angiography were included in this cross-sectional study. Two-dimensional speckle-tracking echocardiography (2DSTE)-derived longitudinal LA myocardial deformation markers were compared between 42 obese and 54 nonobese patients. The longitudinal strain and the longitudinal strain rate of the LA myocardium during the reservoir phase and the contraction phase were reduced in the obese patients with diabetes compared with the nonobese patients with diabetes in the unadjusted analysis. In the adjusted analysis, longitudinal strain and the longitudinal strain rate during the contraction phase and the longitudinal strain rate during the reservoir phase were decreased in the obese patients with diabetes. The reservoir and contraction functions of the LA as evaluated by 2DSTE were decreased in our obese patients with diabetes compared with our nonobese patients with diabetes.

Association of Adipocytokines With Carotid Intima Media Thickness and Arterial Stiffness in Obstructive Sleep Apnea Patients

Objective: Obstructive sleep apnea (OSA) results in increased carotid intima-media thickness (IMT) and arterial stiffness; however, the association between adipocytokines and IMT/arterial stiffness in OSA patients is unclear. Methods: We enrolled 95 normal weight and overweight, not obese, participants from May 2018 to December 2018 in this study. All subjects underwent a carotid artery ultrasound examination and polysomnography. Blood samples were used to determine serum chemerin, adiponectin, SFRP5, and apelin levels. Correlations between two quantitative variables were assessed using the Pearson or Spearman coefficient. Stepwise models of multiple linear regression analysis were performed to assess the independent relationships. Result: IMT in OSA patients was significantly higher than in the non-snorers. There were significant differences in the arterial stiffness parameters such as distensibility coefficient (DC), compliance coefficient (CC), and pulse wave velocity (PWV). SFRP5 level was lower in OSA patients than in non-snorers. Adiponectin correlated with CC, DC, and PWV among OSA patients; however, the relationship disappeared after a multivariable adjustment. Age was independently associated with all quantitative IMT and stiffness indices. AHI and minimum oxygen saturation (Mini SaO₂) were independently related to arterial stiffness. Conclusion: The quantitative IMT and carotid arterial elasticity were significantly worse among OSA patients. Age was the main independent factor correlated with quantitative IMT and arterial stiffness, and AHI and mini SaO₂ were associated factors. There were no relationships between aforementioned adipocytokines and quantitative IMT/carotid arterial stiffness.

Examination of the Relationship Between Metabolic Syndrome and Obstructive Sleep Apnea in Iranian Patients with Type 2 Diabetes: A Case-Control Study

INTRODUCTION

Obstructive sleep apnea (OSA) is a common risk factor for metabolic syndrome (MS) that increases the chance of cardiovascular disease, stroke, and mortality. Many studies have been conducted on this matter, but the results are still conflicting. The aim of the present study was to examine the relationship between metabolic syndrome (MS) and obstructive sleep apnea (OSA) in Iranian patients with type 2 diabetes (T2D).

PATIENTS AND METHODS

This matched case-control study was conducted with 190 patients with T2D in Sanandaj, Iran. The data were selected using the demographic questionnaire, clinical and anthropometric measures, the Berlin Questionnaire (BQ), and the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III). Participants were divided into two groups of high risk of OSA (experimental) and low risk of OSA (control). The data were analyzed using Stata, version 14.

RESULTS

The frequency of MS was higher in the OSA group than the control group (81.1% vs 70.5%), but the group difference was not statistically significant (p=0.127). The results of crude and age-sex adjusted logistic regression analysis revealed no significant association between OSA and the other variables under study (P>0.05). Sensitivity analysis and external adjustment for BMI showed no significant relationship between OSA and the other variables under study (P=0.319).

CONCLUSION

In the present study, no significant association was found between metabolic syndrome (MS) and obstructive sleep apnea (OSA) in patients with T2D; therefore, more studies should be conducted on this subject.

The Ventilatory and Diffusion Dysfunctions in Obese Patients with and without Obstructive Sleep Apnea-Hypopnea Syndrome

OBJECTIVE

To analyze the ventilatory and alveolar-capillary diffusion dysfunctions in case of obesity with or without an OSAS.

METHODS

It is a cross-sectional study of 48 obese adults (23 OSAS and 25 controls). Anthropometric data (height, weight, and body mass index (BMI)) were collected. All adults responded to a medical questionnaire and underwent polysomnography or sleep polygraphy for apnea-hypopnea index (AHI) and percentage of desaturation measurements. The following lung function data were collected: pulmonary flows and volumes, lung transfer factor for carbon monoxide (DLCO), and fraction of exhaled nitric oxide (F_eNO).

RESULTS

Obesity was confirmed for the two groups with a total sample mean value of BMI = 35.06 ± 4.68 kg/m². A significant decrease in lung function was noted in patients with OSAS compared with controls. Indeed, when compared with the control group, the OSAS one had a severe restrictive ventilatory defect (total lung capacity: 93 ± 14 vs. 79 ± 12%), an abnormal DLCO (112 ± 20 vs. 93 ± 22%), and higher bronchial inflammation (18.40 ± 9.20 vs. 31.30 ± 13.60 ppb) (p < 0.05).

CONCLUSION

Obesity when associated with OSAS increases the severity of pulmonary function and alveolar-capillary diffusion alteration. This can be explained in part by the alveolar inflammation.

Intermittent hypoxia and hypercapnia induces inhibitor of nuclear factor-κB kinase subunit β-dependent atherosclerosis in pulmonary arteries

Clinical studies have shown that obstructive sleep apnea (OSA) increases atherosclerosis risk. The inflammation, especially mediated by the macrophages via nuclear factor-κB (NF-κB), has been speculated to contribute to atherogenicity in OSA patients. Inhibitor of NF-κB kinase-β (IKKβ) is an essential element of the NF-κB pathway and is linked to atherosclerosis. We previously reported that atherosclerosis was accelerated in pulmonary artery (PA) but not in aorta when low-density lipoprotein receptor knockout (Ldlr-/-) mice were exposed to intermittent hypoxia/hypercapnia (IHH), a surrogate for recurrent upper-airway obstruction. Therefore, we hypothesized that IKKβ-dependent NF-κB activation in monocytes and macrophages plays a role in IHH-induced PA atherosclerosis. To test this hypothesis, myeloid restricted IKKβ deletion (IkkβΔMye) or control (IkkβF/F) mice were crossed with Ldlr-/- mice to generate double-knockout mice. Then, the mice were exposed to IHH or room air (Air) on high-fat diet for 8 or 16 wk. Lesions of PA and aorta were examined in IkkβΔMye;Ldlr-/- and IkkβF/F;Ldlr-/- male mice under IHH vs. Air. The results revealed that IKKβ deletion abolished IHH-induced PA atherosclerosis after 8-wk exposure but not after 16-wk exposure (8 wk: IkkβF/F;Ldlr-/-, IHH 13.5 ± 1.4 vs. Air 5.7 ± 0.7%, P < 0.01; IkkβΔMye;Ldlr-/-, IHH 7.4 ± 1.9% vs. Air 4.6 ± 1.3%, P = 0.24). Both IKKβ deletion and IHH had no effects on atherosclerosis in the aorta. Our findings demonstrate that IKKβ-dependent NF-κB activity in myeloid-lineage cells plays a critical role in IHH-induced PA atherosclerosis at the early stage.

Prevalence of Sleep Apnea in Patients with Carotid Artery Stenosis

Obstructive sleep apnea (OSA) is a common disease affecting about 13% of men and 6% of women, usually having severe cardiovascular sequalae. OSA is responsible for the systemic inflammatory response and oxidative stress and results in endothelial injury being a risk factor for atherosclerosis. The aim of this study was to estimate the prevalence of OSA among patients with severe carotid artery stenosis. Fifty-five patients (F/M-24/31, mean age 70 ± 7 years, body mass index 28.3 ± 6.3 kg/m²) were enrolled into the study. The patients were qualified for elective surgical treatment of carotid artery stenosis. Polysomnography was performed in all patients the night before surgery. Thirty-six patients underwent surgical endarterectomy and nineteen patients underwent carotid artery stenting. Sleep apnea was diagnosed in 44 (80%) of all patients. The mean apnea-hypopnea index (AHI) was 14.5 ± 12.9. The OSA severity distribution was as follows: 22 mild, 16 moderate, and 6 severe cases. We found that the percentage of carotid endarterectomies was the greatest in mild and moderate OSA. It was approximately twofold greater than that in non-OSA patients. Carotid artery stenting was performed in nearly half of the patients in each of these groups. We conclude that OSA is highly prevalent in patients with carotid artery stenosis scheduled for carotid surgery. Nonetheless, the exact pathogenetic mechanisms underlying mutual interaction between OSA and vascular wall damage remain elusive. OSA is not routinely diagnosed among patients with advanced atherosclerosis. The study results might be an argument for performing polysomnography in patients with carotid artery stenosis.

Obesity and Reproduction

OBJECTIVE

To provide a comprehensive review and evidence-based recommendations for the delivery of fertility care to women with obesity.

OUTCOMES

The impact of obesity on fertility, fertility treatments, and both short and long-term maternal fetal outcomes was carefully considered.

EVIDENCE

Published literature was reviewed through searches of MEDLINE and CINAHL using appropriate vocabulary and key words. Results included systematic reviews, clinical trials, observational studies, clinical practice guidelines, and expert opinions.

VALUES

The Canadian Fertility & Andrology Society (CFAS) is a multidisciplinary, national non-profit society that serves as the voice of reproductive specialists, scientists, and allied health professionals working in the field of assisted reproduction in Canada. The evidence obtained for this guideline was reviewed and evaluated by the Clinical Practice Guideline (CPG) Committee of the CFAS under the leadership of the principal authors.

BENEFITS, HARMS, AND COSTS

The implementation of these recommendations should assist clinicians and other health care providers in counselling and providing reproductive care to women with obesity.

VALIDATION

This guideline and its recommendations have been reviewed and approved by the membership, the CPG Committee and the Board of Directors of the CFAS.

SPONSORS

Canadian Fertility & Andrology Society.

RECOMMENDATIONS

Twenty-one evidence based recommendations are provided. These recommendations specifically evaluate the impact of obesity on natural fertility, fertility treatments, and maternal-fetal outcomes. Strategies to lose weight and BMI cut-offs are also addressed.

Coordinated program between primary care and sleep unit for the management of obstructive sleep apnea

The purpose of this study is to develop and validate a work model in the primary health-care setting for identifying patients with obstructive sleep apnea–hypopnea syndrome (OSAHS) based on clinical variables and an ambulatory sleep monitoring study. After screening, patients with mild–moderate OSAHS could be managed by primary care physicians, whereas those identified with severe OSAHS would be referred to specialists from sleep units for starting specific treatment. The proposed model does not move the entire health-care process to a generally overburdened primary care level and favors the coordinated work and the necessary flexibility to adapt the model to challenges and perspectives of OSAHS.

Sleep Apnea and Sleep Habits: Relationships with Metabolic Syndrome

Excess visceral adiposity is a primary cause of metabolic syndrome and often results from excess caloric intake and a lack of physical activity. Beyond these well-known etiologic factors, however, sleep habits and sleep apnea also seem to contribute to abdominal obesity and metabolic syndrome: Evidence suggests that sleep deprivation and behaviors linked to evening chronotype and social jetlag affect eating behaviors like meal preferences and eating times. When circadian rest and activity rhythms are disrupted, hormonal and metabolic regulations also become desynchronized, and this is known to contribute to the development of metabolic syndrome. The metabolic consequences of obstructive sleep apnea syndrome (OSAS) also contribute to incident metabolic syndrome. These observations, along with the first sleep intervention studies, have demonstrated that sleep is a relevant lifestyle factor that needs to be addressed along with diet and physical activity. Personalized lifestyle interventions should be tested in subjects with metabolic syndrome, based on their specific diet and physical activity habits, but also according to their circadian preference. The present review therefore focuses (i) on the role of sleep habits in the development of metabolic syndrome, (ii) on the reciprocal relationship between sleep apnea and metabolic syndrome, and (iii) on the results of sleep intervention studies.

Association of Obstructive Sleep Apnea With the Risk of Affective Disorders

Importance

Obstructive sleep apnea (OSA) is a common subtype of sleep breathing disorder; however, the association between OSA and the psychological health of affected individuals has not been fully evaluated.

Objective

To investigate the association between OSA and development of affective disorders.

Design, Setting, and Participants

This study used a nationwide representative cohort sample from the Korea National Health Insurance Service-National Sample Cohort database comprising data from 1 025 340 patients. The study included 197 patients with OSA diagnosed between January 2004 and December 2006 and 780 individuals without OSA who were matched using propensity score matching. Data were analyzed from September 28, 2018, to March 30, 2019.

Main Outcomes and Measures

Affective disorder events over a 9-year follow-up period. Kaplan-Meier survival curves with log-rank tests and Cox proportional hazards regression models were used to calculate cumulative incidence and hazard ratios (HRs) of affective disorders for each group.

Results

Of the total population of 985 (860 male [87.3%], 540 [54.8%] were aged <45 years), the incidences per 1000 person-years of affective disorders were 49.57 and 27.18 in the OSA and comparison groups, respectively. A total of 1371.7 person-years in the OSA group and 6328.6 person-years in the comparison group were evaluated for affective disorder events. After adjustment for sociodemographic factors (age, residential area, and household income), disability, and comorbidities, the adjusted HRs for patients with OSA developing affective disorders in patients with OSA during the 9-year follow-up period was 2.04 (95% CI, 1.53-2.70). In a subgroup analysis, the adjusted HRs for patients with OSA who developed depressive and anxiety disorders were 2.90 (95% CI, 1.98-4.24) and 1.75 (95% CI, 1.26-2.44), respectively. Moreover, female patients with OSA had a significant likelihood of prospective development of depression and anxiety (adjusted HR for depression, 3.97 [95% CI, 1.54-10.19]; adjusted HR for anxiety, 2.42 [95% CI, 1.17-5.02]) compared with male patients with OSA (adjusted HR for depression, 2.74 [95% CI, 1.80-4.17]; adjusted HR for anxiety, 1.64 [95% CI, 1.13-2.39]).

Conclusions and Relevance

This observational study using nationwide data suggests that OSA is associated with an increased incidence of affective disorder, such as depression and anxiety. Further studies appear to be needed to confirm our findings and, if validated, then studies are needed to explore the nature of the observed association, including potential causality, between OSA and affective symptoms.

Differential metabolic and inflammatory responses to intermittent hypoxia in substrains of lean and obese C57BL/6 mice

AIMS

This study was to investigate the degree of susceptibility to intermittent hypoxia (IH), a hallmark of obstructive sleep apnea (OSA), between the two mice inbred lines C57BL/6N (6N) and C57BL/6J (6J).

MATERIALS AND METHODS

Four-week old male mice of 6N and 6J substrains (n = 8) were randomized to standard diet (SD) group or high fat (HF) diet group. At the age of 13-week, all two groups of mice were subjected to either air or IH (IH30; thirty hypoxic events per hour) for one week.

KEY FINDINGS

All mice fed with HF diet exhibited obesity with more body weight and fat mass (percentage to body weight) gain. IH reduced serum LDL, HDL and total cholesterol levels in lean 6J mice. In obese mice, IH lowered obesity-induced serum total cholesterol level in 6J substrain but raised further in 6N substrain. Furthermore, IH caused elevation of serum FFA and MDA levels, and pro-inflammatory cytokines MCP-1 and IL-6 levels in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of lean 6J but not lean 6N mice. There was reduced number of adipocytes and elevation of macrophages in SAT and VAT of HF-induced obese mice of both substrains. IH led to increased number of adipocytes and macrophages in SAT of lean 6J mice.

SIGNIFICANCE

The genetic difference between 6N and 6J mice may have direct impact on metabolic and inflammatory responses after IH. Therefore, attention must be given for the selection of C57BL mice substrains in the experimental IH-exposed mouse model.

Predictors of long-term adherence to continuous positive airway pressure in patients with obstructive sleep apnea and cardiovascular disease

Study Objectives

Poor adherence to continuous positive airway pressure (CPAP) commonly affects therapeutic response in obstructive sleep apnea (OSA). We aimed to determine predictors of adherence to CPAP among participants of the Sleep Apnea and cardioVascular Endpoints (SAVE) trial.

Methods

SAVE was an international, randomized, open trial of CPAP plus usual care versus usual care (UC) alone in participants (45–75 years) with co-occurring moderate-to-severe OSA (≥12 episodes/h of ≥4% oxygen desaturation) and established cardiovascular (CV) disease. Baseline sociodemographic, health and lifestyle factors, OSA symptoms, and 1-month change in daytime sleepiness, as well as CPAP side effects and adherence (during sham screening, titration week, and in the first month), were entered in univariate linear regression analyses to identify predictors of CPAP adherence at 24 months. Variables with p <0.2 were assessed for inclusion in a multivariate linear mixed model with country, age, and sex included a priori and site as a random effect.

Results

Significant univariate predictors of adherence at 24 months in 1,121 participants included: early adherence measures, improvement in daytime sleepiness at 1 month, fixed CPAP pressure, some measures of OSA severity, cardiovascular disease history, breathing pauses, and very loud snoring. While observed adherence varied between countries, adherence during sham screening, initial titration, and the first month of treatment retained independent predictive value in the multivariate model along with fixed CPAP pressure and very loud snoring.

Conclusions

Early CPAP adherence had the greatest predictive value for identifying those at highest risk of non-adherence to long-term CPAP therapy.

Clinical Trial Registration

SAVE is registered with clinicaltrials.gov (NCT00738179).

Sleep duration and body mass: direction of the associations from adolescence to young adulthood

Research suggests that sleep duration and obesity are related, but the direction of this association remains uncertain. We applied autoregressive cross-lag models to evaluate the directionality of the relationship between sleep duration and BMI from adolescence through emerging and young adulthood, life stages where the risk for developing obesity are particularly high. Using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), we examined sex-stratified associations between sleep duration and BMI in this cohort from adolescence (ages 12-18, year 1996), to emerging adulthood (ages 18-24, 2001-2002), to young adulthood (ages 24-32, 2008), controlling for key confounders. For both males and females, higher BMI during an earlier developmental stage was associated with shorter sleep duration in the subsequent stage (both Bs = -0.02, ps < 0.01). However, sleep duration at an earlier developmental stage was not associated with BMI at the subsequent stage. Findings suggest that researchers should be cautious when interpreting cross-sectional relationships between sleep and BMI, as higher BMI may precede shorter sleep during adolescence to young adulthood. Researchers may also wish to account for potential bi-directional associations when modeling sleep and BMI using longitudinal data.

Hypoxia exacerbates nonalcoholic fatty liver disease via the HIF-2α/PPARα pathway

This study aimed to investigate whether hypoxia can affect nonalcoholic fatty liver disease (NAFLD) progression and the associated mechanisms, specifically regarding the hypoxia-inducible factor (HIF)-2α/peroxisome proliferator-activated receptor (PPAR)α pathway in vitro and in vivo. Recent studies have reported that, compared with HIF-1α, HIF-2α has different effects on lipid metabolism. We propose hypoxia may exacerbate NAFLD by the HIF-2α upregulation-induced suppression of PPARα in the liver. To verify this hypothesis, a steatotic human hepatocyte (L02) cell line treated with free fatty acids and a mouse model of NAFLD fed a high-fat diet were used. Steatotic hepatocytes were treated with hypoxia, HIF-2α siRNA, PPARα agonists, and inhibitors, respectively. Meanwhile, the NAFLD mice were exposed to intermittent hypoxia or intermittent hypoxia with PPARα agonists. The relative gene expression levels of HIF-1α, HIF-2α, mitochondrial function, fatty acid β-oxidation and lipogenesis were examined. Evidence of lipid accumulation was observed, which demonstrated that, compared with normal hepatocytes, steatotic hepatocytes exhibited higher sensitivity to hypoxia. This phenomenon was closely associated with HIF-2α. Moreover, lipid accumulation in hepatocytes was ameliorated by HIF-2α silencing or a PPARα agonist, despite the hypoxia treatment. HIF-2α overexpression under hypoxic conditions suppressed PPARα, leading to PGC-1α, NRF-1, ESRRα downregulation, and mitochondrial impairment. Additionally, β-oxidation genes such as CPT1α, CPT2α, ACOX1, and ACOX2 were downregulated and lipogenesis genes including LXRα, FAS, and SCD1 were upregulated by hypoxia. Therefore, we concluded that HIF-2α overexpression induced by hypoxia aggravated NAFLD progression by suppressing fatty acid β-oxidation and inducing lipogenesis in the liver via PPARα.