The Bidirectional Relationship Between Obstructive Sleep Apnea and Metabolic Disease

Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. γ-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis.

Obstructive Sleep Apnea Syndrome and Obesity Indicators, Circulating Blood Lipid Levels, and Adipokines Levels: A Bidirectional Two-Sample Mendelian Randomization Study

Purpose

This investigation sought to elucidate the genetic underpinnings that connect obesity indicators, circulating blood lipid levels, adipokines levels and obstructive sleep apnea syndrome (OSAS), employing a bidirectional two-sample Mendelian randomization (MR) analysis that utilizes data derived from extensive genome-wide association studies (GWAS).

Methods

We harnessed genetic datasets of OSAS available from the FinnGen consortium and summary data of four obesity indices (including neck circumference), seven blood lipid (including triglycerides) and eleven adipokines (including leptin) from the IEU OpenGWAS database. We primarily utilized inverse variance weighted (IVW), weighted median, and MR-Egger methods, alongside MR-PRESSO and Cochran's Q tests, to validate and assess the diversity and heterogeneity of our findings.

Results

After applying the Bonferroni correction, we identified significant correlations between OSAS and increased neck circumference (Odds Ratio [OR]: 3.472, 95% Confidence Interval [CI]: 1.954-6.169, P= 2.201E-05) and decreased high-density lipoprotein (HDL) cholesterol levels (OR: 0.904, 95% CI: 0.858-0.952, P= 1.251E-04). Concurrently, OSAS was linked to lower leptin levels (OR: 1.355, 95% CI: 1.069-1.718, P= 0.012) and leptin receptor levels (OR: 0.722, 95% CI: 0.530-0.996, P= 0.047). Sensitivity analyses revealed heterogeneity in HDL cholesterol and leptin indicators, but further multiplicative random effects IVW method analysis confirmed these correlations as significant (P< 0.05) without notable heterogeneity or horizontal pleiotropy in other instrumental variables.

Conclusion

This investigation compellingly supports the hypothesis that OSAS could be a genetic predisposition for elevated neck circumference, dyslipidemia, and adipokine imbalance. These findings unveil potential genetic interactions between OSAS and metabolic syndrome, providing new pathways for research in this domain. Future investigations should aim to delineate the specific biological pathways by which OSAS impacts metabolic syndrome. Understanding these mechanisms is critical for developing targeted prevention and therapeutic strategies.

Modelling metabolic performance in paediatric obstructive sleep disordered breathing: A case-control study

Paediatric obstructive sleep disordered breathing (OSDB) has a considerable impact on cardiovascular physiology, but the consequences on children's basal metabolism and response to exercise are far from being known. The objective was to propose model estimations for paediatric OSDB metabolism at rest and during exercise. A retrospective case-control analysis of data from children submitted to otorhinolaryngology surgery was performed. The heart rate (HR) was measured, while oxygen consumption (VO2) and energy expenditure (EE) at rest and during exercise were obtained using predictive equations. The results for the patients with OSDB were compared with controls. A total of 1256 children were included. A total of 449 (35.7%) had OSDB. The patients with OSDB showed a significantly higher resting heart rate (94.55 ± 15.061 bpm in OSDB vs. 92.41 ± 15.332 bpm in no-OSDB, p = 0.041). The children with OSDB showed a higher VO2 at rest (13.49 ± 6.02 mL min-1kg-1 in OSDB vs. 11.55 ± 6.83 mL min-1kg-1 in no-OSDB, p = 0.004) and a higher EE at rest (67.5 ± 30.10 cal min-1kg-1 in OSDB vs. 57.8 + 34.15 cal min-1kg-1 in no-OSDB, p = 0.004). At maximal exercise, patients with OSDB showed a lower VO2max (33.25 ± 5.82 mL min-1kg-1 in OSDB vs. 34.28 ± 6.71 in no-OSDB, p = 0.008) and a lower EE (166.3 ± 29.11 cal min-1kg-1 in OSDB vs. 171.4 ± 33.53 cal min-1kg-1 in no-OSDB, p = 0.008). The VO2/EE increment with exercise (Δ VO2 and Δ EE) was lower in OSDB for all exercise intensities (p = 0.009). This model unveils the effect of paediatric OSDB on resting and exercise metabolism. Our findings support the higher basal metabolic rates, poorer fitness performance, and cardiovascular impairment found in children with OSDB.

Circadian dysfunction and cardio-metabolic disorders in humans

The topic of human circadian rhythms is not only attracting the attention of clinical researchers from various fields but also sparking a growing public interest. The circadian system comprises the central clock, located in the suprachiasmatic nucleus of the hypothalamus, and the peripheral clocks in various tissues that are interconnected; together they coordinate many daily activities, including sleep and wakefulness, physical activity, food intake, glucose sensitivity and cardiovascular functions. Disruption of circadian regulation seems to be associated with metabolic disorders (particularly impaired glucose tolerance) and cardiovascular disease. Previous clinical trials revealed that disturbance of the circadian system, specifically due to shift work, is associated with an increased risk of type 2 diabetes mellitus. This review is intended to provide clinicians who wish to implement knowledge of circadian disruption in diagnosis and strategies to avoid cardio-metabolic disease with a general overview of this topic.

Correlation between serum leptin level and sleep monitoring indexes in patients with obstructive sleep apnea hypopnea syndrome and its predictive value: a cross-sectional analysis

Objective

To investigate the association between serum leptin (LP) level and polysomnography (PSG) parameters in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).

Methods

A cross-sectional study was conducted. The data of subjects who underwent PSG at hospital between January 2021 and December 2022 were collected retrospectively, 220 participants were included. The subjects were categorized into simple snoring group (n = 45), mild OSAHS group (n = 63), moderate OSAHS group (n = 52), and severe OSAHS group (n = 60). The general characteristics, PSG indices, and serological indices were collected retrospectively. Pearson correlation analysis was used to observe the correlation between serum LP level and PSG parameters. The value of serum LP level in predicting OSAHS was analyzed by receiver operating characteristic curve.

Results

The serum LP level was positively correlated with micro-arousal count, micro-arousal index (MAI), high apnea hypopnea index, times of blood oxygen decreased by≥3% and time in saturation lower 90%, and negatively correlated with lowest nocturnal oxygen saturation and mean oxygen saturation (p < 0.05). The area under the curve (AUC) of serum LP level in predicting the occurrence of OSAHS was 0.8276 (95% CI: 0.7713-0.8839), and when the Youden index was 0.587, the sensitivity was 72.00%, and the specificity was 86.67% (p < 0.0001). In the population with high MAI, the AUC of serum LP level in predicting the occurrence of OSAHS was 0.8825 (95% CI: 0.7833-0.9817), and when the Youden index was 0.690, the sensitivity was 79.00% and the specificity was 90.00% (p < 0.0001).

Conclusion

Serum LP level is associated with the severity of OSAHS. Serum LP level demonstrates a strong predictive value for the occurrence of OSAHS, particularly in population with high MAI.

Effect of Weight Loss on the Apnea Hypopnea Index is Related to Waist Circumference in Chinese Adults with Overweight and Obesity

Purpose

The present study aimed to evaluate the efficiency of traditional anthropometric and body composition parameters in predicting apnea hypopnea index (AHI) change after weight loss.

Patients and Methods

Chinese adults with overweight and obesity were included into this study containing two parts. A cross-sectional study was conducted in 137 individuals using the baseline data from two weight loss intervention trials. The second part was the weight-loss intervention study conducted in 60 overweight and obese patients with obstructive sleep apnea (OSA). All participants underwent physical examination, bioelectrical impedance analysis and overnight polysomnography. Multivariate linear regression models were used to identify the most accurate parameters to predict AHI and the mediation analysis to evaluate the mediators between weight loss and AHI reduction.

Results

Waist circumference (WC), body mass index and fat mass were positively associated with AHI after adjusting multiple collinearities in the cross-sectional study. After weight-loss intervention, body weight decreased from 94.6 ± 15.3 to 88.0 ± 13.9 kg, and AHI decreased from 41.9 (13.0,66.9) to 20.7 (8.7,51.2) events/h. Among these parameters, only percentage changes in WC and AHI across the intervention were positively intercorrelated after controlling for covariates (adjusted r = 0.271, P = 0.041). The mediation analysis supported WC as a mediator between weight loss and AHI reduction (standardized indirect effect [95% CI] = 4.272[0.936,7.999]).

Conclusion

Both general and abdominal obesity are of high prognostic value for OSA. WC as an easily accessible parameter mediates the effects of weight loss in decreasing OSA severity.

[Sleep disorders in patients with chronic tinnitus]

Tinnitus has a lifetime prevalence of 25% in Germany. A common comorbidity in chronic cases are sleep disorders. The aims of this study were to detect sleep disorders and to identify possible associations with tinnitus parameters.Fifty patients with chronic tinnitus were recruited. The patients underwent audiometry, polysomnography, and completed standardised questionnaires on tinnitus and sleep behaviour.Data were available in 30 men and 9 women (age 50.2 ± 11 y, BMI 28.8 ± 4.4 kg/m²). The median duration of tinnitus was 36 (9; 120) months with a severity score of 2.00 (1.00; 3.00). The mean Tinnitus Questionnaire (TF) score was 43.6 ± 17.1, the Epworth Sleepiness Scale (ESS) score was 8.41 ± 4.27, the Pittsburgh Sleep Quality Index (PSQI) score was 9.21 ± 4.32, and the Screening Scale for Chronic Stress (SSCS) score was 58.13 ± 9.58.Sleep diagnoses included 18 cases of insomnia, 4 cases of RLS, and 11 cases of OSA. Patients with sleep comorbidities showed higher tinnitus severity, PSQI scores, and body weight compared to those without sleep disorders.Worse sleep quality was associated with higher tinnitus severity (p=0.038) and more disruptive tinnitus (p=0.03). Patients with subjectively highly disruptive tinnitus reported higher chronic stress scores. Tinnitus duration was correlated with OSA-severity (p=0.026).More than two-thirds of tinnitus patients showed sleep disorders as comorbidity. A sleep screening appears useful in cases of increased tinnitus severity. Whether CPAP therapy is helpful in reducing tinnitus symptoms could not be conclusively determined but deserves further attention.

Smoking Disturbs the Beneficial Effects of Continuous Positive Airway Pressure Therapy on Leptin Level in Obstructive Sleep Apnea

Background

This study aimed to determine how smoking alters the effect of positive airway pressure (PAP) therapy on metabolic syndrome in obstructive sleep apnea (OSA).

Methods

In this clinical trial, morphometric measures, metabolic syndrome parameters, and apnea-hypopnea index (AHI) in OSA patients were recorded and compared between active smokers and non-smokers. The mean change in metabolic syndrome parameters measured before and after 3 months of PAP therapy was determined. The study included 72 males and 43 females.

Results

Morphometric values and mean AHI did not differ between active smokers and non-smokers. When the percentage of unchanged, increased, or decreased metabolic parameters measured before and after treatment was analyzed, leptin level tended to increase in active smokers with OSA after PAP therapy compared with non-smokers (P=0.034, adjusted for confounders).

Conclusion

Serum leptin level was stable or decreased in non-smokers, while 40% of active smokers had increased leptin level. Therefore, smoking plays a predisposing role in leptin resistance despite PAP therapy in OSA patients.

Urinary metabolite signatures reflect the altered host metabolism in severe obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder. The onset and progression of OSA are often linked with severe cardiovascular and metabolic comorbidities. At the same time, given the increasing prevalence of OSA, novel methods to screen OSA and its follow-up are needed. Untargeted metabolic profiling of OSA patients and healthy controls was planned to capture a snapshot of urinary metabolites and potential biomarkers using the gas chromatography-mass spectrometry (GC-MS) method.Polysomnography (PSG) confirmed severe OSA patients with AHI index ≥ 30 were considered for urine sample collection. The sample size was constituted of OSA (n = 36) and healthy controls (n = 36). Metabolite extraction and derivatization were performed and metabolomic analysis was performed by using GC-MS.The obtained data set was statistically analyzed using univariate and multivariate analysis. The Orthogonal partial least-squares discriminant analysis (OPLS-DA) was performed to screen differential metabolites between OSA patients and healthy controls.The metabolomic analysis revealed a total of 142 significantly altered metabolites of interest.Biomarker analysis allows for the creation of a list of putative urinary biomarkers including GABA, malic acid, glutamic acid, epichoric acid etc., with an accuracy of 99.8 % to 100 % for OSA screening. Subsequently, pathway analysis revealed that related biochemical pathways like the tricarboxylic acid cycle (TCA), glutamate/glutamine, amino acid and fatty acid metabolism, that are significantly interlinked with these metabolic biomarkers can play a crucial role in the pathogenesis of OSA. This study paves the way to undertake mass screening in a larger population to identify specific and reliable biomarkers.

A retrospective study of the role of hypercapnia in patients with acromegaly

BACKGROUND

Acromegaly is a multisystemic disease characterized by an excessive release of growth hormone (GH) and insulin-like growth factor-1. Obstructive sleep apnea (OSA) is a common consequence of acromegaly, and hypercapnia is frequently observed in patients with acromegaly, OSA, and obesity. However, the effects of hypercapnia on acromegaly remain unknown. This study was designed to investigate whether there are differences in clinical symptoms, sleep variables, and biochemical remission after surgery for acromegaly in patients with OSA with or without hypercapnia.

METHODS

A retrospective analysis was conducted involving patients with acromegaly and OSA. The pharmacotherapy history for acromegaly before surgery, anthropometric measures, blood gas, sleep monitoring data, and biochemical assays of hypercapnic and eucapnic individuals were collected 1-2 weeks before surgery. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for failed postoperative biochemical remission.

RESULTS

In this study, 94 patients with OSA and acromegaly were included. Among them, 25 (26.6%) had hypercapnia. The hypercapnic group had higher body mass index (92% vs. 62.3%; p = 0.005) and poorer nocturnal hypoxemia index. No serological differences were found between the two groups. According to the post-surgery GH level, 52 patients (55.3%) reached biochemical remission. Univariate logistic regression analysis revealed that diabetes mellitus (odds ratio [OR], 2.59; 95% confidence interval [CI], 1.02-6.55), instead of hypercapnia (OR, 0.61; 95% CI, 0.24-1.58), was associated with lower remission rates. Patients who received pharmacotherapy for acromegaly before surgery (OR, 0.21; 95% CI, 0.06-0.79) and had higher thyroid-stimulating hormone levels (OR, 0.53; 95% CI, 0.32-0.88) were more likely to have biochemical remission after surgery. Multivariate analysis further showed that only diabetes mellitus (OR, 3.29; 95% CI, 1.15-9.46) and preoperative pharmacotherapy (OR, 0.21; 95% CI, 0.06-0.83) remained significant. Hypercapnia, hormone levels, and sleep indicators had no effect on biochemical remission after surgery.

CONCLUSIONS

Single-center evidence shows that hypercapnia alone may not be a risk factor for lower biochemical remission rates. Correcting hypercapnia does not appear to be required before surgery. More evidence is needed to further support this conclusion.

Sleep disturbances in individuals with down syndrome: An overview

Down Syndrome, or Trisomy 21, is one of the most common birth defects, with 6,000 babies born annually with Down Syndrome in the U.S. One of many health risk factors individuals with Down Syndrome experience is sleep issues, ranging from poor sleep quality to high prevalence of obstructive sleep apnea. This literature review aims to review these sleep challenges in this population and explore consequences and treatment options.

Obstructive sleep apnea and metabolic syndrome

Metabolic syndrome (MS) is a heterogeneous condition associated with increased cardiovascular risk. There is growing evidence from experimental, translational, and clinical investigations that has suggested that obstructive sleep apnea (OSA) is associated with prevalent and incident components of MS and MS itself. The biological plausibility is supportive, primarily related to one of the main features of OSA, namely intermittent hypoxia: increased sympathetic activation with hemodynamic repercussions, increased hepatic glucose output, insulin resistance through adipose tissue inflammation, pancreatic β-cell dysfunction, hyperlipidemia through the worsening of fasting lipid profiles, and the reduced clearance of triglyceride-rich lipoproteins. Although there are multiple related pathways, the clinical evidence relies mainly on cross-sectional data preventing any causality assumptions. The overlapping presence of visceral obesity or other confounders such as medications challenges the ability to understand the independent contribution of OSA on MS. In this review, we revisit the evidence on how OSA/intermittent hypoxia could mediate adverse effects of MS parameters independent of adiposity. Particular attention is devoted to discussing recent evidence from interventional studies. This review describes the research gaps, the challenges in the field, perspectives, and the need for additional high-quality data from interventional studies addressing the impact of not only established but promising therapies for OSA/obesity.

Is obstructive sleep apnea a circadian rhythm disorder?

Obstructive sleep apnea is the most common sleep-related breathing disorder worldwide and remains underdiagnosed. Its multiple associated comorbidities contribute to a decreased quality of life and work performance as well as an increased risk of death. Standard treatment seems to have limited effects on cardiovascular and metabolic aspects of the disease, emphasising the need for early diagnosis and additional therapeutic approaches. Recent evidence suggests that the dysregulation of circadian rhythms, processes with endogenous rhythmicity that are adjusted to the environment through various cues, is involved in the pathogenesis of comorbidities. In patients with obstructive sleep apnea, altered circadian gene expression patterns have been demonstrated. Obstructive respiratory events may promote circadian dysregulation through the effects of sleep disturbance and intermittent hypoxia, with subsequent inflammation and disruption of neural and hormonal homeostasis. In this review, current knowledge on obstructive sleep apnea, circadian rhythm regulation, and circadian rhythm sleep disorders is summarised. Studies that connect obstructive sleep apnea to circadian rhythm abnormalities are critically evaluated. Furthermore, pathogenetic mechanisms that may underlie this association, most notably hypoxia signalling, are presented. A bidirectional relationship between obstructive sleep apnea and circadian rhythm dysregulation is proposed. Approaching obstructive sleep apnea as a circadian rhythm disorder may prove beneficial for the development of new, personalised diagnostic, therapeutic and prognostic tools. However, further studies are needed before the clinical approach to obstructive sleep apnea includes targeting the circadian system.

The integrated brain network that controls respiration

Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.

Beyond Counting Sheep: Exploring the Link between Polycystic Ovary Syndrome and Sleep Health

Polycystic ovary syndrome (PCOS) is a common hormonal condition with reproductive, metabolic, and psychological sequelae that affects 8 to 13% of reproductive-aged women and 3 to 11% of adolescent girls. Sleep is often compromised in women with PCOS due to increased rates of sleep problems, with the most established problem being obstructive sleep apnea (OSA). OSA is highly prevalent in reproductive-aged adult women with PCOS, but not so in adolescence. The international evidence-based PCOS guideline to improve health outcomes in women with PCOS indicated routine screening to identify and alleviate symptoms of OSA. The guidelines, however, did not weigh other multidimensional constructs of sleep health such as sleep disturbances (e.g., sleep quality and quantity), beyond OSA. This is perhaps due to the lack of research and existing mixed findings in the area of PCOS and sleep health. This narrative review summarizes the current knowledge about OSA and expands further to include the limited knowledge about other sleep problems in PCOS among reproductive-aged women and adolescent girls. We broadly cover the prevalence, risk factors, and mechanisms of sleep problems in PCOS and their relationship with cardiometabolic and psychological health. A brief summary on treatment and intervention strategies for sleep problems in PCOS and future recommendations will be deliberated.

A Bidirectional Association Between Obstructive Sleep Apnea and Metabolic-Associated Fatty Liver Disease

Obesity is considered a twentieth-century epidemic and is a growing concern among health professionals. Obesity and its complications contribute to multiple chronic illnesses, such as type 2 diabetes (T2D), metabolic syndrome, obstructive sleep apnea (OSA), malignancy, and cardiovascular and liver diseases. In the last two decades, a bidirectional association between OSA and metabolic-associated fatty liver disease (MAFLD), independent of obesity, has been established. Both conditions have similar risk factors and metabolic comorbidities that may imply a common disease pathway. This review compiles the evidence and delineates the relationship between OSA and MAFLD from a clinical and diagnostic aspect.

The causal relationships between obstructive sleep apnea and elevated CRP and TNF-α protein levels

BACKGROUND

Obstructive sleep apnea (OSA) and inflammation are closely related. This study aimed to evaluate the associations and causal effect between C-reactive protein (CRP) and tumour necrosis factor-alpha (TNF-α) levels andOSA.

METHODS

Pooled analysis was conducted to compare the expression differences of CRP and TNF-α between OSA patients with different severity and controls, and between continuous positive airway pressure (CPAP) and non-CPAP interventions for OSA patients. Using published GWAS summary statistics, we conducted a bidirectional two-sample Mendelian Randomization (MR) to estimate the causal relationships between CRP and TNF-α levels and OSA risk. Effect estimates were evaluated using inverse-variance weighted (IVW) as primary method, and several other MR methods as sensitivity analysis.

RESULTS

Both TNF-α (WMD [95%CI] = 5.86 [4.80-6.93] pg/ml, p < .00001) and CRP (WMD [95%CI] = 2.66 [2.15-3.17] mg/L, p < .00001), showed a significant increase in OSA patients compared with controls and this increasing trend was associated with OSA severity. Besides, compared to blank control (non-CPAP), CPAP treatment can reduce high TNF-α (WMD [95%CI]= -4.44 [-4.81, -4.07]pg/ml, p < .00001) and CRP (WMD [95%CI]= -0.91 [-1.65, -0.17] mg/l, p = .02) in OSA. Moreover, the primary MR analysis by IVW showed that OSA was the genetically predicted cause of elevated CRP (estimate: 0.095; 95% CI, [0.010-0.179]; p = .029) using six SNPs as the instrument variable, which were repeated by weighted median (estimate: 0.053; 95% CI, [0.007, 0.100]; p =.024) and MR RAPS (estimate: 0.109; 95% CI, [0.079, 0.140]; p = 1.98x10^-12). Besides, the causal effect from elevated CRP on increased OSA risk was almost significant by IVW (OR:1.053; 95% CI, [1.000, 1.111]; p = .053). However, there were no causal associations between TNF-α and OSA from both directions.

CONCLUSIONS

Increased CRP and TNF-α were associated with OSA severity and sensible to CPAP treatment. Also, OSA had a suggestive causal effect on elevated CRP.

Sleep disordered breathing and haemoglobin A1c levels within or over normal range and ageing or sex differences: the Nagahama study

Recently an association between blood glucose dysregulation and sleep disruption was suggested. The association between sleep disordered breathing, most of which is due to obstructive sleep apnea (OSA) in the general population, and diabetic severity, as well as the impact of antidiabetic treatment, remains unclear. This study aimed to investigate these associations as well as age and sex differences. This cross-sectional study evaluated 7,680 community participants as the main cohort (population-based cohort). OSA was assessed by the 3% oxygen desaturation index from pulse oximetry, which was corrected for sleep duration obtained by wrist actigraphy. For arguing the limitations for using pulse oximetry, 597 hospitalised patients, who were assessed by the apnea-hypopnea index from attended polysomnography, were also evaluated as the validation cohort (hospital-based cohort). Moderate-to-severe OSA was more prevalent as haemoglobin A1c (HbA1c) levels increased (<5.6%/5.6%-<6.5%/6.5%-<7.5%/≥7.5%, respectively) in both cohorts (p < 0.001), but only in those without antidiabetic treatment. The HbA1c level was an independent factor for moderate-to-severe OSA (population-based cohort, odds ratio [OR] 1.26, 95% confidence interval [CI] 1.10-1.45; hospital-based cohort, OR 1.69, 95% CI 1.22-2.33, per 1% increase). These associations were more prominent in the middle-aged (aged <60 years) than in the elderly (aged ≥60 years) and in women than in men in both cohorts. The prevalence of moderate-to-severe OSA in patients with antidiabetic treatment in the hospital-based cohort was ≥75% regardless of HbA1c levels. In conclusion, an association between the prevalence of OSA and HbA1c level even within or over the normal range was found only in patients without antidiabetic treatment and was more prominent in the middle-aged and in women.

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

Obstructive sleep apnoea (OSA) is associated with cardiovascular and metabolic comorbidities, including hypertension, dyslipidaemia, insulin resistance and atherosclerosis. Strong evidence suggests that OSA is associated with an altered lipid profile including elevated levels of triglyceride-rich lipoproteins and decreased levels of high-density lipoprotein (HDL). Intermittent hypoxia; sleep fragmentation; and consequential surges in the sympathetic activity, enhanced oxidative stress and systemic inflammation are the postulated mechanisms leading to metabolic alterations in OSA. Although the exact mechanisms of OSA-associated dyslipidaemia have not been fully elucidated, three main points have been found to be impaired: activated lipolysis in the adipose tissue, decreased lipid clearance from the circulation and accelerated de novo lipid synthesis. This is further complicated by the oxidisation of atherogenic lipoproteins, adipose tissue dysfunction, hormonal changes, and the reduced function of HDL particles in OSA. In this comprehensive review, we summarise and critically evaluate the current evidence about the possible mechanisms involved in OSA-associated dyslipidaemia.

Insulin Resistance, Hyperglycemia, and Risk of Developing Obstructive Sleep Apnea in Men and Women in the United States

Rationale: Recent prospective studies suggest diabetes as a risk factor for the development of obstructive sleep apnea (OSA). However, the extent to which diabetes-related traits, such as hyperglycemia and insulin resistance, are related to OSA risk remains uncertain. Objectives: To examine the risk of developing OSA according to baseline concentrations of fasting insulin and hemoglobin A1c (HbA1c). Methods: Participants from four prospective U.S. cohorts were included: NHS (Nurses' Health Study; 2002-2012), NHSII (Nurses' Health Study II; 1995-2013), HPFS (Health Professionals Follow-up Study; 1996-2012), and MESA (Multi-Ethnic Study of Atherosclerosis; 2000-2012). OSA was assessed by self-reported clinical diagnosis in NHS/NHSII/HPFS and at-home polysomnography in MESA (defined as Apnea-Hypopnea Index ⩾30). Results: Of 9,283 participants with fasting insulin data, 790 (8.5%) developed OSA over 10 to 18 years of follow-up. After adjusting for sociodemographic, lifestyle, and comorbidity factors, the odds ratio for incident OSA comparing the extreme quintiles of fasting insulin was 3.59 (95% confidence interval, 2.67-4.82; P-trend < 0.0001). Of 6,342 participants with HbA1c data, 715 (11.3%) developed OSA. The comparable odds ratio for HbA1c was 2.21 (95% confidence interval, 1.69-2.89; P-trend < 0.0001). Additional adjustment for body mass index and waist circumference attenuated the associations for fasting insulin (P-trend = 0.005) and HbA1c (P-trend = 0.03). In the fully adjusted model simultaneously including both biomarkers, only fasting insulin but not HbA1c was associated with OSA risk. Conclusions: Independent of obesity, insulin resistance may play a more important role than hyperglycemia in the pathogenesis of OSA. Given the limitation of using self-reported diagnosis to exclude baseline prevalent OSA cases, additional studies are needed to further establish the temporal relationship and assess whether improving insulin resistance may reduce OSA risk.

Caloric restriction prevents obesity- and intermittent hypoxia-induced cardiac remodeling in leptin-deficient ob/ob mice

Background: Intermittent hypoxia (IH), a key characteristic of obstructive sleep apnea, is independently associated with cardiometabolic impairment. While endogenous leptin levels may provide cardioprotective effects against hypoxia, leptin resistance is common among obese individuals presenting with obstructive sleep apnea.

Methods: Here, we assessed left ventricle (LV) function using M-mode echocardiography in lean wild-type, calorically-restricted ob/ob, and obese ob/ob mice before and after 6 days of IH to determine how obesity and intermittent hypoxia interact to affect cardiac function independent of leptin signaling.

Results: Calorically-restricting ob/ob mice for 4 weeks prior to IH exposure prevented weight gain (−2.1 ± 1.4 g) compared to free-fed ob/ob mice (8.7 ± 1.1 g). Free-fed ob/ob mice exhibited increased LV mass (0.713 ± 0.008 g) relative to wild-type mice (0.685 ± 0.004 g) and increased posterior wall thickness (0.089 ± 0.006 cm) relative to calorically-restricted ob/ob mice (0.072 ± 0.004 cm). Following 6 days of IH, free-fed ob/ob mice exhibited increases in cardiac output (44.81 ± 2.97 pre-IH vs. 57.14 ± 3.09 ml/min post-IH), LV diameter (0.400 ± 0.007 pre-IH vs. 0.428 ± 0.009 cm post-IH) and end diastolic volume (0.160 ± 0.007 pre-IH vs. 0.195 ± 0.012 ml post-IH) that were not detected in wild-type or calorically-restricted ob/ob mice.

Conclusion: Caloric restriction can prevent obesity-induced LV hypertrophy and protect against acute IH-induced cardiac remodeling independent of leptin signaling. These findings may have clinical implications for obstructive sleep apnea.

Obstructive Sleep Apnea and Nonalcoholic Fatty Liver Disease in the General Population: A Cross-Sectional Study Using Nationally Representative Data

(1) Background: To evaluate the association between obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD) in the general population using a nationally representative sample from South Korea; (2) Methods: This study included 4275 adults aged ≥40 years who completed the snoring, tiredness, observed apnea, high blood pressure, body mass index (BMI), age, neck circumference, and gender (STOP-Bang) questionnaire. The risk of OSA was stratified into low, intermediate, and high grades according to the STOP-Bang score. The prevalence of NAFLD according to the STOP-Bang score was calculated, and the increasing trend was measured. A complex sample multivariable regression analysis with adjustments for possible confounding variables was used to calculate the odds ratio of NAFLD and advanced fibrosis. Subgroup analysis was conducted with stratification based on sex and obesity status; (3) Results: We identified 1021 adults with NAFLD and 3254 adults without NAFLD. The prevalence of NAFLD increased significantly with higher STOP-Bang scores in both men and women. Participants of both sexes with high STOP-Bang scores were more likely to have NAFLD. Compared to non-obese individuals, the risk of NAFLD according to the STOP-Bang score was more intense in obese individuals. With respect to hepatic steatosis, there was no significant association between advanced fibrosis and STOP-Bang score; (4) Conclusions: OSA, the risk of which was measured using the STOP-Bang model, was closely associated with NAFLD in both Korean men and women. Clinicians should consider screening for NAFLD in individuals with a high STOP-Bang score.

Influence of diet and sport on the risk of sleep apnea in patients with metabolic syndrome associated with hypothyroidism - a 4-year survey

Apnea is a common problem observed among obese individuals, affecting the quality of sleep and increasing cardiovascular risk and mortality. The current study monitored the risk of obstructive sleep apnea (OSA) following diet therapy and sports-associated diet therapy in patients with metabolic syndrome (MS) and hypothyroidism. The subjects included in the study were divided into 3 groups: control group (CG) (n=36), diet therapy group (DG) (including patients following a personalized diet therapy program) (n=76), and diet therapy and sports group (DSG) (which considered patients doing sports in addition to following a personalized diet therapy program) (n=80). The evaluation methods included body analysis (body mass index, fat mass, and visceral fat), paraclinical analysis (homeostasis model assessment of insulin resistance), assessment of difficulty in breathing, stress monitoring, hypothyroidism, and risk of OSA. The OSA index was assessed using the Berlin Questionnaire of Sleep Apnea and Epworth Sleepiness Scale. The correlation between OSA with body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR) index, fat mass, and visceral fat showed a statistically significant positive ratio (p<0.05; F=3.871). The obtained results indicated that diet therapy and physical activity reduced the OSA risk by 78.72%.

A portrait of obstructive sleep apnea risk factors in 27,210 middle-aged and older adults in the Canadian Longitudinal Study on Aging

Determining the prevalence and characteristics of individuals susceptible to present with obstructive sleep apnea (OSA) is essential for developing targeted and efficient prevention and screening strategies. We included 27,210 participants aged ≥45 years old (50.3% women) from the Canadian Longitudinal Study on Aging. Using the STOP questionnaire combined to the percentage of body fat (%BF), we estimated the prevalence of individuals at high-risk for OSA in a sex and age-specific manner, and tested the relation with comorbidities, menopause and systemic inflammation. The prevalence was 17.5%, and was lower in women (13.1%) than in men (21.9%). A high level of high-sensitivity C-reactive protein was the strongest factor associated with OSA risk and this association was 1.3-2.3 times higher in women than in men. OSA risk increased with age, cardiovascular diseases, diabetes mellitus, anxio-depressive symptoms, asthma and arthritis. In women, post-menopausal status was associated with a high OSA risk. Nearly 1 adult out of 5 older than 45 is at risk for OSA in Canada. Comorbidities, menopause and systemic inflammation, more than age, explain increased OSA prevalence. Considering this high prevalence and associations with medical and mental comorbidities, health care practitioners should incorporate systematic OSA screening in their clinical procedures.

You Cannot Hit Snooze on OSA: Sequelae of Pediatric Obstructive Sleep Apnea

Pediatric obstructive sleep apnea (OSA) has been shown to not only affect the quality of sleep, but also overall health in general. Untreated or inadequately treated OSA can lead to long-term sequelae involving cardiovascular, endothelial, metabolic, endocrine, neurocognitive, and psychological consequences. The physiological effects of pediatric OSA eventually become pathological. As the complex effects of pediatric OSA are discovered, they must be identified early so that healthcare providers can be better equipped to treat and even prevent them. Ultimately, adequate management of OSA improves overall quality of life.

Association of Metabolic Syndrome With Long-Term Cardiovascular Risks and All-Cause Mortality in Elderly Patients With Obstructive Sleep Apnea

Background

Evidence suggests that an increased risk of major adverse cardiac events (MACE) and all-cause mortality is associated with obstructive sleep apnea (OSA), particularly in the elderly. Metabolic syndrome (MetS) increases cardiovascular risk in the general population; however, less is known about its influence in patients with OSA. We aimed to assess whether MetS affected the risk of MACE and all-cause mortality in elderly patients with OSA.

Methods

From January 2015 to October 2017, 1,157 patients with OSA, aged ≥60 years, no myocardial infarction (MI), and hospitalization for unstable angina or heart failure were enrolled at baseline and were followed up prospectively. OSA is defined as an apnea-hypopnea index of ≥5 events per hour, as recorded by polysomnography. Patients were classified on the basis of the presence of MetS, according to the definition of the National Cholesterol Education Program (NCEP). Incidence rates were expressed as cumulative incidence. Cox proportional hazards analysis was used to estimate the risk of all events. The primary outcomes were MACE, which included cardiovascular death, MI, and hospitalization for unstable angina or heart failure. Secondary outcomes were all-cause mortality, components of MACE, and a composite of all events.

Results

MetS was present in 703 out of 1,157 (60.8%) elderly patients with OSA. During the median follow-up of 42 months, 119 (10.3%) patients experienced MACE. MetS conferred a cumulative incidence of MACE in elderly patients with OSA (log-rank, P < 0.001). In addition, there was a trend for MACE incidence risk to gradually increase in individuals with ≥3 MetS components (P = 0.045). Multivariate analysis showed that MetS was associated with an incidence risk for MACE [adjusted hazard ratio (aHR), 1.86; 95% confidence interval (CI), 1.17–2.96; P = 0.009], a composite of all events (aHR, 1.54; 95% CI, 1.03–2.32; P = 0.036), and hospitalization for unstable angina (aHR, 2.01; 95% CI, 1.04–3.90; P = 0.039). No significant differences in the risk of all-cause mortality and other components of MACE between patients with and without MetS (P > 0.05). Subgroup analysis demonstrated that males (aHR, 2.23; 95% CI, 1.28–3.91, P = 0.05), individuals aged <70 years (aHR, 2.36; 95% CI, 1.27–4.39, P = 0.006), overweight and obese individuals (aHR, 2.32; 95% CI, 1.34–4.01, P = 0.003), and those with moderate-severe OSA (aHR, 1.81;95% CI: 1.05–3.12, P = 0.032) and concomitant MetS were at a higher risk for MACE.

Conclusion

MetS is common in elderly patients with OSA in the absence of MI, hospitalization for unstable angina or heart failure. Further, it confers an independent, increased risk of MACE, a composite of all events, and hospitalization for unstable angina. Overweight and obese males, aged <70 years with moderate-severe OSA combined with MetS presented a significantly higher MACE risk.

Development and Comparison of Predictive Models Based on Different Types of Influencing Factors to Select the Best One for the Prediction of OSAHS Prevalence

OBJECTIVE

This study aims to retrospectively analyze numerous related clinical data to identify three types of potential influencing factors of obstructive sleep apnea-hypopnea syndrome (OSAHS) for establishing three predictive nomograms, respectively. The best performing one was screened to guide further clinical decision-making.

METHODS

Correlation, difference and univariate logistic regression analysis were used to identify the influencing factors of OSAHS. Then these factors are divided into three different types according to the characteristics of the data. Lasso regression was used to filter out three types of factors to construct three nomograms, respectively. Compare the performance of the three nomograms evaluated by C-index, ROC curve and Decision Curve Analysis to select the best one. Two queues were obtained by randomly splitting the whole queue, and similar methods are used to verify the performance of the best nomogram.

RESULTS

In total, 8 influencing factors of OSAHS have been identified and divided into three types. Lasso regression finally determined 6, 3 and 4 factors to construct mixed factors nomogram (MFN), baseline factors nomogram (BAFN) and blood factors nomogram (BLFN), respectively. MFN performed best among the three and also performed well in multiple queues.

CONCLUSION

Compared with BAFN and BLFN constructed by single-type factors, MFN constructed by six mixed-type factors shows better performance in predicting the risk of OSAHS.

Interaction effects between characteristics of obstructive sleep apnea and obesity on dyslipidemia

OBJECTIVES

Obstructive sleep apnea (OSA) and obesity often coexist, and both can increase the risk of dyslipidemia. However, the interaction effects between the characteristics of OSA and obesity on dyslipidemia are not yet known. This study was performed to investigate this issue.

METHODS

Basic characteristics, polysomnography data, and biochemical markers of patients with suspected OSA seen at the First Affiliated Hospital of Nanchang University were collected. Serum lipid levels were compared after adjusting for multiple confounders. We used binary logistic regression models to assess the interaction effects of the oxygen desaturation index (ODI) and obesity, and the apnea-hypopnea index (AHI) and obesity, on dyslipidemia.

RESULTS

A total of 343 patients were included in the study. After adjusting for multiple confounders, there were no differences in serum lipid levels between non-obese or obese patients with an AHI ≤ 30 and AHI > 30, and no interaction effect between the AHI and obesity on dyslipidemia. Obese patients, but not non-obese ones, with an ODI > 37.5 had significantly higher total cholesterol (TC) levels, and higher TC/high-density lipoprotein cholesterol (HDL-C) ratios, than patients with an ODI ≤ 37.5. In addition, a significant positive multiplicative interaction effect between obesity and the ODI was found on hyper-TC (odds ratio [OR] = 3.459; 95% confidence interval [CI] = 1.104, 10.838; p = 0.03).

CONCLUSION

A positive interaction effect was detected between obesity and intermittent hypoxia on dyslipidemia. Therefore, further attention should be paid to dyslipidemia in obese patients with intermittent hypoxia.

The timing of intermittent hypoxia differentially affects macronutrient intake and energy substrate utilization in mice

Sleep apnea is a common sleep disorder characterized by periodic breathing cessation and intermittent hypoxia (IH). Although previous studies have demonstrated that IH alone can influence metabolic outcomes such as body weight, it remains unclear how the timing of IH can specifically affect these outcomes. Here, we examine how pairing 10-h periods of IH to either the animals' resting phase (e.g., IH during the day) or active phase (e.g., IH during the night) differentially affects body weight, macronutrient selection, energy expenditure, respiratory exchange rate, and glucose tolerance. We find that in contrast to mice exposed to IH during the night, mice exposed to IH during the day preferentially decrease their carbohydrate intake and switch to fat metabolism. Moreover, when the IH stimulus was removed, mice that had been exposed to day IH continued to eat a minimal amount of carbohydrates and consumed a higher percentage of kilocalorie from fat for at least 5 days. These data demonstrate that food choice and substrate utilization are secondary to the timing of IH but not IH itself. Taken together, these data have key clinical implications for individuals with sleep apnea and particularly those who are also experiencing circadian disruption such as night-shift workers.NEW & NOTEWORTHY Pairing repeated hypoxic episodes to a mouse's resting phase during the day preferentially decreases carbohydrate intake and results in a switch to metabolic fat oxidation. These data indicate that the timing of intermittent hypoxia should be considered when calculating sleep apnea's effects on metabolic outcomes.

Correlation between nocturnal oxygen desaturation and glycemic control in diabetic patients with obstructive sleep apnea

Background

Nocturnal hypoxia occurring in obstructive sleep apnea (OSA) is associated with different metabolic disturbances. The present study aims to correlate between nocturnal oxygen desaturation and levels of glycemic control in patients with type 2 diabetes mellitus (T2DM) and undiagnosed OSA.

Results

The present study included 107 patients with T2DM referred for assessment of sleep-related breathing disorder, there were 62 males (57.94%) and 45 females (42.05%), and their age ranged from 42 to 72 years with an average age of 61.29 ± 6.68 years. The patients were divided into 2 groups according to the results of overnight pulse oximetry (OPO) and apnea-hypopnea index (AHI) detected by polysomnography. Group 1 included 68 patients, they had moderate to severe OSA and significant nocturnal desaturation, and group 2 included 39 patients with no or mild OSA. The baseline characteristics of the two groups were not significantly different. Group 1 patients showed significantly higher mean Epworth score and more symptoms related to OSA. There was statistically significant difference between the values of ODI (24.88 ± 9.21 versus 8.94 ± 2.38), AHI (27.10 ± 7.68 versus 9.02 ± 3.90), and hemoglobin A1c levels (8.04 ± 0.64 versus 6.79 ± 0.38) between the two groups. A positive correlation was found between nocturnal oxygen desaturation and levels of HbA1c in group 1 patients reflecting worse glycemic control in patients with moderate to severe OSA.

Conclusion

Nocturnal oxygen desaturation occurring in obstructive sleep apnea is associated with poor glycemic control in patients with type 2 diabetes mellitus.

Trial registration

ClinicalTrials.gov, Protocol ID: OPO10-18. Trial registry number: NCT04711083. Date of registration: 14 January 2021, retrospectively registered.

Photoperiod Manipulation Reveals a Light-Driven Component to Daily Patterns of Ventilation in Male C57Bl/6J Mice

Obstructive sleep apnea is a common sleep disorder that increases risk for cardiovascular disease and mortality. The severity of sleep-disordered breathing in obstructive sleep apnea patients fluctuates with the seasons, opening the possibility that seasonal changes in light duration, or photoperiod, can influence mechanisms of breathing. Photoperiod can have profound effects on internal timekeeping and can reshape metabolic rhythms in mammals. While the daily rhythm in ventilation is largely shaped by the metabolic rate, less is known about whether ventilatory rhythms are altered in accordance with metabolism under different photoperiods. Here, we investigate the relationship between ventilation and metabolism under different photoperiods using whole-body plethysmography and indirect calorimetry. We find that the daily timing of ventilation is chiefly synchronized to dark onset and that light cues are important for maintaining daily ventilatory rhythms. Moreover, changes in ventilatory patterns are not paralleled by changes in oxygen consumption, energy expenditure, or respiratory exchange rate under different photoperiods. We conclude that ventilatory patterns are not only shaped by the metabolic rate and circadian timing but are also influenced by other light-driven factors. Collectively, these findings have clinical implications for the seasonal variations in sleep-disordered breathing found in individuals with obstructive sleep apnea.

Association of apnea-hypopnea index during rapid eye movement sleep with insulin resistance in patients with suspected obstructive sleep apnea: a cross-sectional study

Background

Obstructive sleep apnea (OSA) is associated with insulin resistance. However, the association between special stages of OSA [rapid eye movement (REM) sleep] and insulin resistance is not clear. This study was designed to assess the association of the frequency of respiratory events during REM sleep with insulin resistance in adults with suspected OSA.

Methods

In this cross-sectional study, 4,062 adult participants with suspected OSA who underwent polysomnography in our sleep center between 2009 and 2016 were screened. Polysomnographic variables, biochemical indicators, and physical measurements were collected. Logistic regression analyses were conducted to determine the odds ratios (ORs) and 95% confidence intervals (95% CIs) for insulin resistance as assessed by the presence of hyperinsulinemia, the homeostasis model assessment of insulin resistance (HOMA-IR) index, the fasting insulin resistance index (FIRI), and Bennett’s insulin sensitivity index (ISI).

Results

The final analyses included 2,899 adults with suspected OSA. Multivariate adjustments, including the apnea-hypopnea index (AHI) during non-REM sleep (AHI_NREM), were performed. The AHI during REM sleep (AHI_REM) was found to be independently associated with insulin resistance across increasing AHI_REM quartiles. For hyperinsulinemia the ORs (95% CIs) followed the order of 1.340 (1.022, 1.757), 1.210 (0.882, 1.660), and 1.632 (1.103, 2.416). For abnormal HOMA-IR, ORs (95% CIs) were 1.287 (0.998, 1.661), 1.263 (0.933, 1.711), and 1.556 (1.056, 2.293). For abnormal FIRI, ORs (95% CIs) were 1.386 (1.048, 1.835), 1.317 (0.954, 1.818), and 1.888 (1.269, 2.807). For abnormal Bennett’s ISI, ORs (95% CIs) were 1.297 (1.003, 1.678), 1.287 (0.949, 1.747), and 1.663 (1.127, 2.452). All linear trends were statistically significant (P<0.01). Additionally, the results showed that REM sleep duration was independently associated with hyperinsulinemia (OR =0.777, 95% CI: 0.615–0.982; P<0.05).

Conclusions

AHI_REM was independently associated with hyperinsulinemia and an abnormal HOMA-IR, FIRI, and Bennett’s ISI in adults with suspected OSA. Additionally, REM sleep duration was independently associated with hyperinsulinemia.

Impact of insomnia and obstructive sleep apnea on the risk of acute exacerbation of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major health burden worldwide. Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is characterized by worsening of patients' respiratory symptoms that requires a modification in medication. This event could accelerate disease progression and increase the risk of hospital admissions and mortality. Both insomnia and obstructive sleep apnea (OSA) are prevalent in patients with COPD, and are linked to increased susceptibility to AECOPD. Improper treatment of insomnia may increase the risk of adverse respiratory outcomes for patients with COPD, while effective continuous positive airway pressure (CPAP) treatment may reduce the risk of AECOPD and mortality in patients with overlap syndrome. Sleep disorders should be considered in clinical management for COPD.

Common risk factors and therapeutic targets in obstructive sleep apnea and osteoarthritis: An unexpectable link?

Osteoarthritis (OA) and Obstructive Sleep Apnea (OSA) are two highly prevalent chronic diseases for which effective therapies are urgently needed. Recent epidemiologic studies, although scarce, suggest that the concomitant occurrence of OA and OSA is associated with more severe manifestations of both diseases. Moreover, OA and OSA share risk factors, such as aging and metabolic disturbances, and co-morbidities, including cardiovascular and metabolic diseases, sleep deprivation and depression. Whether this coincidental occurrence is fortuitous or involves cause-effect relationships is unknown. This review aims at collating and integrating present knowledge on both diseases by providing a brief overview of their epidemiology and pathophysiology, analyzing current evidences relating OA and OSA and discussing potential common mechanisms by which they can aggravate each other. Such mechanisms constitute potential therapeutic targets whose pharmacological modulation may provide more efficient ways of reducing the consequences of OA and OSA and, thus, lessen the huge individual and social burden that they impose.

[Masterplan 2025 of the Austrian Society of Pneumology (ASP)-the expected burden and management of respiratory diseases in Austria]

Scientific Members of the Austrian Society of Pneumology describe the expected development in respiratory health and provide guidance towards patient-oriented and cost-efficient respiratory care in Austria.Methods: In November 2017, respiratory care providers (physicians, nurses, physiotherapists) together with patient's advocacy groups and experts in health development, collaborated in workshops on: respiratory health and the environment, bronchial asthma and allergy, COPD, pediatric respiratory disease, respiratory infections, sleep disorders, interventional pneumology, thoracic oncology and orphan diseases.Results: Respiratory disease is extremely prevalent and driven by ill-health behavior, i.e. cigarette smoking, over-eating and physical inactivity. For the majority of respiratory diseases increased prevalence, but decreased hospitalizations are expected.The following measures should be implemented to deal with future challenges:1. Screening and case-finding should be implemented for lung cancer and COPD.2. E-health solutions (telemedicine, personal apps) should be used to facilitate patient management.3. Regional differences in respiratory care should be reduced through E‑health and harmonization of health insurance benefits across Austria.4. Patient education and awareness, to reduce respiratory health illiteracy should be increased, which is essential for sleep disorders but relevant also for other respiratory diseases.5. Respiratory care should be inter-professional, provided via disease-specific boards beyond lung cancer (for ILDs, sleep, allergy)6. Programs for outpatient's pulmonary rehabilitation can have a major impact on respiratory health.7. Increased understanding of molecular pathways will drive personalized medicine, targeted therapy (for asthma, lung cancer) and subsequently health care costs.

A Leptin-Mediated Neural Mechanism Linking Breathing to Metabolism

Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of the solitary tract (NTS) mimics the respiratory stimulation after systemic leptin administration. We show that leptin activates the sodium leak channel (NALCN), thereby depolarizing a subset of glutamatergic (VGluT2) LepRb NTS neurons expressing galanin. Mice with selective deletion of NALCN in LepRb neurons have increased breathing irregularity and central apneas. On a high-fat diet, these mice gain weight with an associated depression of minute ventilation and tidal volume, which are not detected in control littermates. Anatomical mapping reveals LepRb NTS-originating glutamatergic axon terminals in a brainstem inspiratory premotor region (rVRG) and dorsomedial hypothalamus. These findings directly link a defined subset of NTS LepRb cells to the matching of ventilation to energy balance.

Influence of multiple apolipoprotein A-I and B genetic variations on insulin resistance and metabolic syndrome in obstructive sleep apnea

Background

The relationships between apolipoprotein A-I (APOA-I), apolipoprotein B (APOB) with insulin resistance, metabolic syndrome (MetS) are unclear in OSA. We aimed to evaluate whether the multiple single nucleotide polymorphism (SNP) variants of APOA-I and APOB exert a collaborative effect on insulin resistance and MetS in OSA.

Methods

Initially, 12 APOA-I SNPs and 30 APOB SNPs in 5259 subjects were examined. After strict screening, four APOA-I SNPs and five APOB SNPs in 4007 participants were included. For each participant, the genetic risk score (GRS) was calculated based on the cumulative effect of multiple genetic variants of APOA-I and APOB. Logistic regression analyses were used to evaluate the relationships between APOA-I/APOB genetic polymorphisms, insulin resistance, and MetS in OSA.

Results

Serum APOB levels increased the risk of insulin resistance and MetS adjusting for age, gender and BMI [odds ratio (OR = 3.168, P < 0.001; OR = 6.098, P < 0.001, respectively]. APOA-I GRS decreased the risk of insulin resistance and MetS after adjustments (OR = 0.917, P = 0.001; OR = 0.870, P < 0.001, respectively). APOB GRS had no association with insulin resistance (OR = 1.364, P = 0.610), and had weak association with MetS after adjustments (OR = 1.072, P = 0.042). In addition, individuals in the top quintile of the APOA-I genetic score distribution had a lower risk of insulin resistance and MetS after adjustments (OR = 0.761, P = 0.007; OR = 0.637, P < 0.001, respectively).

Conclusions

In patients with OSA, cumulative effects of APOA-I genetic variations decreased the risk of insulin resistance and MetS, whereas multiple APOB genetic variations had no associations with insulin resistance and weak association with MetS.

Metabolic Syndrome in Children and Adolescents: Is There a Universally Accepted Definition? Does it Matter?

The concept of metabolic syndrome (MetS) as a cluster of cardiovascular risk factors (obesity, altered glucose metabolism, dyslipidemia, and hypertension) has been around for more than 30 years. It is considered to be the result of complex interactions between centrally located fat, insulin resistance, subclinical inflammation, and other factors in genetically predisposed individuals. MetS diagnosis in adults has been linked to increased risk for cardiovascular disease (CVD) and type 2 diabetes mellitus (T2D). However, MetS in children and adolescents remains a controversial issue despite the extensive research in the field. It is still uncertain which definition should be used for its diagnosis in this age group, what is the clinical significance of such a diagnosis, and how reliably it can predict the future risk of developing CVD and T2D. Even if a child is diagnosed with MetS, management includes addressing each of the syndrome's components individually with weight loss and lifestyle modifications as the basic approach. Co-morbid conditions, such as nonalcoholic fatty liver disease, obstructive sleep apnea, and polycystic ovary syndrome should also be considered. It seems that MetS in children and adolescents should be used clinically as a conceptual framework for the identification of risk factors clustered around obesity and insulin resistance rather than a syndrome that needs to be diagnosed by measuring absolute "all-or-none" criteria.

Leptin: Master Regulator of Biological Functions that Affects Breathing

Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO₂ sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.

Effects of different obesity-related adipokines on the occurrence of obstructive sleep apnea

Obstructive sleep apnea (OSA), characterized by recurrent episodes of apnea during sleep and daytime sleepiness, seriously affects human health and may lead to systemic organ dysfunction. The pathogenesis of OSA is complex and still uncertain, but multiple surveys have shown that obesity is an important factor, and the incidence of OSA in people with obesity is as high as 30%. Adipokines are a group of proteins secreted from adipocytes, which are dysregulated in obesity and may contribute to OSA. Here, we review the most important and representative research results regarding the correlation between obesity-related adipokines including leptin, adiponectin, omentin-1, chemerin, and resistin and OSA in the past 5 years, provide an overview of these key adipokines, and analyze possible intrinsic mechanisms and influencing factors. The existing research shows that OSA is associated with an increase in the serum levels of leptin, chemerin, and resistin and a decrease in the levels of adiponectin and omentin-1; the findings presented here can be used to monitor the development of OSA and obesity, prevent future comorbidities, and identify risk factors for cardiovascular and other diseases, while different adipokines can be linked to OSA through different pathways such as insulin resistance, intermittent hypoxia, and inflammation, among others. We hope our review leads to a deeper and more comprehensive understanding of OSA based on the relevant literature, which will also provide directions for future clinical research.

Short-Term Assessment of Obstructive Sleep Apnea Syndrome Remission Rate after Sleeve Gastrectomy: a Cohort Study

BACKGROUND

Severe obesity is associated with a high prevalence of moderate-to-severe obstructive sleep apnea syndrome (OSA). Bariatric surgery has been shown to effectively reduce excess weight and comorbidities.

METHODS

We evaluated the remission rate of moderate-to-severe OSA (apnea-hypopnea index (AHI) ≥ 15) following sleeve gastrectomy. We performed a single-center retrospective chart review of all patients who underwent preoperative polysomnography (PSG) or polygraphy before primary sleeve gastrectomy. Patients with moderate-to-severe OSA treated by continuous positive airway pressure (CPAP) also underwent postoperative PSG. Bivariate analysis was performed to evaluate the criteria associated with remission of moderate-to-severe OSA.

RESULTS

From 2013 to 2018, 39 of 162 patients (24.1%) scheduled for sleeve gastrectomy (SG) presented moderate-to-severe OSA requiring CPAP. Postoperative PSG was performed in 36 patients a mean of 9.9 ± 6.1 months after SG. Mean BMI decreased from 47.4 ± 8.4 to 36.3 ± 7.1 kg/m² (p < 0.001), and all patients reported clinical improvement of OSA symptoms. A remission of moderate-to-severe OSA was observed in 72.2% of patients with a mean decrease of AHI from 45.8 events/h to 11.3 events/h (p < 0.001). Postoperative neck circumference was the only factor associated with OSA remission.

CONCLUSION

SG is associated with a rapid improvement of moderate-to-severe OSA partially as a result of a reduction of neck circumference. However, the absence of correlation with excess weight loss suggests that other weight-independent factors may also be involved.

The relationship between obstructive sleep apnea syndrome and obesity: A new perspective on the pathogenesis in terms of organ crosstalk

INTRODUCTION

Obstructive sleep apnea syndrome (OSAS) is a common disorder that has a major impact on public health. The connection between OSAS and obesity is very complex and likely represents an interaction between biological and lifestyle factors. Oxidative stress, inflammation and metabolic dysregulation are both actors involved in the pathogenesis of OSAS and obesity. Also, the current evidence suggests that gut microbiota plays a significant role in the emergence and progression of some metabolic disorders. When the relationship between OSAS and obesity is evaluated extensively, it is understood that they show mutual causality with each other, and that metabolic challenges such as impaired microbiota affect this bidirectional organ interaction, and by ensuing organ injury.

OBJECTIVES

The aim of this study is to investigate the association between OSAS and obesity, and the effect of "organ crosstalk" on the pathogenesis of the relationship and to contribute to the diagnosis and treatment options in the light of current data.

DATA SOURCE

We performed an electronic database search including PubMed, EMBASE and Web of Science. We used the following search terms: OSAS, obesity, inflammation, metabolic dysregulation and gut microbiota.

CONCLUSION

Obesity and OSAS adversely affect many organs and systems. Besides the factors affecting the diagnosis of the OSAS-obesity relationship, mutual organ interactions among the respiratory system, adipose tissue and intestines should not be ignored for prevention and treatment of OSAS and obesity. Comprehensive clinical trials addressing the efficacy and efficiency of current or potential treatments on therapeutic applications in the OSAS-obesity relationship are needed.

Obstructive sleep apnea and hypertriglyceridaemia share common genetic background: Results of a twin study

Obstructive sleep apnea is associated with an increased risk of hypertension, diabetes and dyslipidaemia. Both obstructive sleep apnea and its comorbidities are at least partly heritable, suggesting a common genetic background. Our aim was to analyse the heritability of the relationship between obstructive sleep apnea and its comorbidities using a twin study. Forty-seven monozygotic and 22 dizygotic adult twin pairs recruited from the Hungarian Twin Registry (mean age 51 ± 15 years) attended an overnight diagnostic sleep study. A medical history was taken, blood pressure was measured, and blood samples were taken for fasting glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and lipoprotein (a). To evaluate the heritability of obstructive sleep apnea and its comorbidities bivariate analysis was performed with an adjustment for age, gender, body mass index (BMI) and smoking after false discovery rate correction and following exclusion of patients on lipid-lowering and antidiabetic medications. There was a significant correlation between indices of obstructive sleep apnea severity, such as the apnea-hypopnea index, oxygen desaturation index and percentage of sleep time spent with oxygen saturation below 90%, as well as blood pressure, serum triglyceride, lipoprotein (a) and glucose levels (all p < .05). The bivariate analysis revealed a common genetic background for the correlations between serum triglyceride and the oxygen desaturation index (r = .63, p = .03), as well as percentage of sleep time spent with oxygen saturation below 90% (r = .58, p = .03). None of the other correlations were significantly genetically or environmentally determined. This twin study demonstrates that the co-occurrence of obstructive sleep apnea with hypertriglyceridaemia has a genetic influence and heritable factors play an important role in the pathogenesis of dyslipidaemia in obstructive sleep apnea.

Obstructive Sleep Apnea Exacerbates Glucose Dysmetabolism and Pancreatic β-Cell Dysfunction in Overweight and Obese Nondiabetic Young Adults

PURPOSE

This study aimed to investigate the effects of obstructive sleep apnea (OSA) on the pancreatic β-cells dysfunction and their implications in the glucose dysmetabolism of overweight and obese nondiabetic young adults.

MATERIALS AND METHODS

The cross-sectional analysis included 422 subjects (261 males/161 females) with the mean age of 27.77 ± 7.51 years and average body mass index (BMI) of 34.84 ± 5.69 kg/m². All subjects underwent polysomnography (PSG), oral glucose tolerance-insulin releasing test (OGTT-IRT) and serum glycosylated hemoglobin A1 (HbA1c) measurement. The glucose metabolism and pancreatic β-cell function in relation to measures of OSA were determined adjustment for important confounders such as age and sex.

RESULTS

OSA subjects accounted for 54.91% in the normal glucose tolerance (NGT) group and 72.11% in the prediabetes (preDM) group (P =0.001). HbA1c was the highest in the preDM subjects with severe OSA. In the NGT subjects, the 1-h glucose level significantly elevated with the OSA severity, and the homeostasis model assessment-β (HOMA-β) was negatively related to nocturnal mean SpO₂ (P <0.05). In the preDM subjects, HOMA-β, early phase insulinogenic index (∆I₃₀/∆G₃₀), total area under the curve of insulin in 180 min (AUC-I₁₈₀), and the oral disposition index (DI_O) were the lowest in the severe OSA group. DI_O was associated with higher oxygen desaturation index (ODI) and lower nocturnal mean SpO₂, and AUC-I₁₈₀ was negatively related to TS90 (P <0.05).

CONCLUSION

Our study indicated higher prevalence of OSA in overweight and obese nondiabetic young adults, especially preDM subjects. The impaired glucose tolerance was observed early after glucose intake in the NGT subjects. OSA induces compensatory increase in the pancreatic β-cell function in the NGT subjects, while pancreatic β-cell dysfunction is present in the preDM subjects with severe OSA.