Obstructive sleep apnea syndrome is associated with metabolic syndrome rather than insulin resistance

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Snoring and components of metabolic syndrome in Southeastern Chinese adults: A community-based study

INTRODUCTION

Snoring has been associated with a number of abnormal conditions, but little work has been done on its association with components of metabolic syndrome based on the epidemiology in Chinese adults.

OBJECTIVE

This study aimed to investigate the association between snoring and components of metabolic syndrome in southeastern Chinese adults.

METHODS

A two-stage, cross-sectional community-based study was performed in Fuzhou, Southeast China, from 2005 to 2009. Stage 1: 5500 subjects were administered a questionnaire. Data on self-reported snoring status, daytime somnolence, demographic data, disease histories, and potential confounders were collected and anthropometric measurements were performed. Stage 2: 1000 subjects who were already investigated underwent a blood test and measurement of blood pressure.

RESULTS

Data from 4286 subjects were available; 606 subjects were habitual snorers. The prevalence of overweight or obesity, hyperglycemia, hypertension, and dyslipidemia in occasional and habitual snorers was higher than that in the study population (16.66%, 7.89%, 10.52%, and 5.81%, respectively). A significantly increasing trend based on snoring frequency existed in the prevalence of metabolic disorders. The prevalence of components of metabolic syndrome continued to be significantly associated with snoring frequency after controlling confounding factors. Odds ratios of suffering from the aforementioned conditions for occasional and habitual snorers were 1.5-2.5 (P < 0.05) and 2.4-4.8 (P < 0.001) times higher, respectively, compared with nonsnorers.

CONCLUSIONS

The prevalence of snoring and components of metabolic syndrome is high in southeastern Chinese adults. Both habitual and occasional snoring are closely associated with metabolic disorders independent of confounding factors.

Meta-analyses of the Association of Sleep Apnea with Insulin Resistance, and the Effects of CPAP on HOMA-IR, Adiponectin, and Visceral Adipose Fat

OBJECTIVE

We sought to conduct an updated meta-analysis of randomized controlled trials (RCTs) on the effect of continuous positive airway pressure (CPAP) on insulin resistance, as measured by homeostasis model assessment of insulin resistance (HOMA-IR), visceral abdominal fat (VAF), and adiponectin. Additionally, we performed a separate meta-analysis and meta-regression of studies on the association of insulin resistance and obstructive sleep apnea (OSA).

METHODS

All included studies were searched from PubMed (from conception to March 15, 2014). Data were pooled across all included RCTs as the mean difference in HOMA-IR and VAF, and as the standardized mean difference in the case of adiponectin analysis. From the included case-control studies, data on the difference of HOMA-IR between cases and controls were pooled across all studies, as the standardized mean difference (SMD).

RESULTS

There was a significant difference in HOMA-IR (-0.43 [95% CIs: -0.75 to -0.11], p = 0.008) between CPAP treated and non CPAP treated participants. However, there was no significant difference in VAF or adiponectin; (-47.93 [95% CI: -112.58 to 16.72], p = 0.14) and (-0.06 [95% CI: -0.28 to 0.15], p = 0.56), respectively. Meta-analysis of 16 case-control studies showed a pooled SMD in HOMA-IR of 0.51 (95% CI: 0.28 to 0.75), p ≤ 0.001, between cases and controls.

CONCLUSIONS

The results of our meta-analyses show that CPAP has a favorable effect on insulin resistance. This effect is not associated with any significant changes in total adiponectin levels or amount of VAF. Our findings also confirm a significant association between OSA and insulin resistance.

Sleep-disordered breathing, type 2 diabetes and the metabolic syndrome

Sleep-disordered breathing (SDB) encompasses a spectrum of conditions that can lead to altered sleep homeostasis. In particular, obstructive sleep apnoea (OSA) is the most common form of SDB and is associated with adverse cardiometabolic manifestations including hypertension, metabolic syndrome and type 2 diabetes, ultimately increasing the risk of cardiovascular disease. The pathophysiological basis of these associations may relate to repeated intermittent hypoxia and fragmented sleep episodes that characterize OSA which drive further mechanisms with adverse metabolic and cardiovascular consequences. The associations of OSA with type 2 diabetes and the metabolic syndrome have been described in studies ranging from epidemiological and observational studies to controlled trials investigating the effects of OSA therapy with continuous positive airway pressure (CPAP). In recent years, there have been rising prevalence rates of diabetes and obesity worldwide. Given the established links between SDB (in particular OSA) with both conditions, understanding the potential influence of OSA on the components of the metabolic syndrome and diabetes and the underlying mechanisms by which such interactions may contribute to metabolic dysregulation are important in order to effectively and holistically manage patients with SDB, type 2 diabetes or the metabolic syndrome. In this article, we review the literature describing the associations, the possible underlying pathophysiological mechanisms linking these conditions and the effects of interventions including CPAP treatment and weight loss.

Obstructive sleep apnoea and diabetes: an update

PURPOSE OF REVIEW

The relationship between obstructive sleep apnoea (OSA) and dysglycaemia is well established. However, uncertainty remains as to the extent that obesity mediates this relationship. The impact of OSA treatment on glucose metabolism and the consequences of having OSA in patients with diabetes is unclear. This review aims to summarize the latest evidence regarding the links between OSA and dysglycaemia.

RECENT FINDINGS

OSA is associated with insulin resistance in lean individuals and predicts insulin resistance worsening longitudinally. Continuous positive airway pressure (CPAP) lowers insulin resistance in CPAP-compliant patients. OSA is associated with impaired β-cell function. In patients with type 2 diabetes (T2D), the association between OSA and glycosylated haemoglobin (HbA1c) is related to nocturnal hypoxaemia. Apnoea hypopnoea index (AHI) during rapid eye movement (REM) (not non-REM) sleep is associated with HbA1c. In-laboratory, supervised CPAP improves glycaemia. OSA is associated with and predicts the progression of some diabetic vascular complications. Intensive lifestyle intervention in patients with T2D improves OSA independent of weight loss.

SUMMARY

OSA is associated with insulin resistance and β-cell dysfunction independent of obesity. OSA is associated with HbA1c and vascular complications in patients with T2D. CPAP might improve insulin resistance and glycaemic measures. Lifestyle intervention has a significant impact on AHI in patients with T2D.

Obstructive Sleep Apnoea and Type 2 Diabetes

With the growing prevalence of obesity, the burden of type 2 diabetes is increasing. Obstructive sleep apnoea (OSA) is a very common medical condition that is associated with increased risk of cardiovascular disease and mortality. Obesity is a common risk factor for OSA and type 2 diabetes and hence it is not surprising that OSA and type 2 diabetes are interlinked. OSA has been shown to be an independent risk factor for the development of incident pre-diabetes/type 2 diabetes. OSA is also associated with worse glycaemic control and vascular disease in patients with type 2 diabetes. However, evidence for the benefits of OSA treatment in patients with type 2 diabetes is still lacking. The aim of this article is to provide an overview of OSA, the relationships between OSA and dysglycaemia and the impact of OSA in patients with type 2 diabetes, highlighting recent advances in the field.

Obstructive sleep apnea and metabolic syndrome in spanish population

Obstructive sleep apnea (OSA) is a clinical picture characterized by repeated episodes of obstruction of the upper airway. OSA is associated with cardiovascular risk factors, some of which are components of metabolic syndrome (MS).

OBJECTIVES

First, determine the prevalence of MS in patients with OSA visited in sleep clinic. Second, evaluate whether there is an independent association between MS components and the severity of OSA.

METHODS

Patients with clinical suspicion of OSA were evaluated by polysomnography. Three groups were defined according to apnea hypoapnea index (AHI): no OSA (AHI <5), mild-moderate (AHI≥ 5 ≤30), and severe (AHI> 30). All patients were determined in fasting blood glucose, total cholesterol, HDL cholesterol, triglycerides and insulin. MS was defined according to criteria of National Cholesterol Education Program (NCEP).

RESULTS

A total of 141 patients (mean age 54 ± 11 years) were evaluated. According to AIH, 25 subjects had no OSA and 116 had OSA (41mild-moderate and 75 severe). MS prevalence ranged from 43-81% in OSA group. Also, a significant increase in waist circumference, triglycerides, glucose, blood pressure levels, and a decrease in HDL cholesterol levels was observed in more severe OSA patients. All polysomnographic parameters correlated significantly with metabolic abnormalities. After a multiple regression analysis, abdominal obesity (p <0.02), glucose (p <0.01) and HDL cholesterol (p <0.001) were independently associated with OSA.

CONCLUSIONS

Our findings show high prevalence of MS in OSA, especially in severe group. A significant association between OSA and some of the components of MS was found in Spanish population.

Impact of Obstructive Sleep Apnoea on Type 2 Diabetes and Vice Versa

Type 2 diabetes and obstructive sleep apnoea (OSA) are diseases with high prevalence and major public health impact. There is evidence that OSA is independently associated with alterations in glucose metabolism. Furthermore, OSA is a significant risk factor for the development of type 2 diabetes. Possible causes might be intermittent hypoxaemia and sleep fragmentation with increased oxidative stress and sympathetic activity, which are typical features of OSA. OSA might also be a reason for ineffective treatment of type 2 diabetes. There is further evidence that the treatment of OSA by continuous positive airway pressure (CPAP) therapy might improve glucose metabolism. On the other hand, there are also hints in the literature that type 2 diabetes might induce sleep apnoea, especially in patients with autonomic neuropathy, but that OSA also facilitates the development of neuropathy in terms of mutual interactions between OSA, type 2 diabetes and diabetic neuropathy. Based on the current scientific data, clinicians have to be aware of the relations between OSA and type 2 diabetes, both from the sleep medical and the diabetological point of view.

Obstructive sleep apnea syndrome: complaints and housing characteristics in a population in the United States

CONTEXT AND OBJECTIVE Obstructive sleep apnea syndrome (OSAS) is one of the leading causes of morbidity and mortality in adults. Early detection of the disorder and discovery of risk factors through standardized questionnaires will lead to reduction of the OSAS burden. The main aim of this study was to estimate the prevalence of OSAS symptoms and examine their association with housing characteristics. DESIGN AND SETTING Cross-sectional study at a medical school. METHODS Demographic, housing and body measurement data on 5,545 individuals aged 16 years and over of various races were selected from the National Health and Nutrition Examination Survey. We analyzed the probability of OSAS based on habitual snoring combined with daytime sleepiness and/or witnessed apnea. Univariate and multiple linear regression were used. RESULTS 9.8% of the men and 6.9% of the women reported symptoms suggestive of OSAS (habitual snoring, daytime sleepiness and/or apnea). The following prevalences of symptoms were found among males and females respectively: frequent snoring 35.1%, 22.3%, excessive daytime sleepiness 6.4%, 3.4% and frequent apnea 14.9%, 20.6%. Using multiple linear regression, OSAS symptoms were correlated with gender, age, body mass index (BMI), marital status and education. Regarding housing characteristics, mildew or musty smell and pets in the environment were associated with a high probability of OSAS. CONCLUSION OSAS symptoms were more prevalent than in developing countries. The environment was an important risk factor, but environmental factors are easier to control and manage than other variables like BMI or socioeconomic status.

Obstructive sleep apnea and type 2 diabetes

Type 2 diabetes and obstructive sleep apnea (OSA) are diseases with high prevalence and major public health impact. There is evidence that regular snoring and OSA are independently associated with alterations in glucose metabolism. Thus, OSA might be a risk factor for the development of type 2 diabetes. Possible causes might be intermittent hypoxia and sleep fragmentation, which are typical features of OSA. OSA might also be a reason of ineffective treatment of type 2 diabetes. There is further evidence that the treatment of OSA by continuous positive airway pressure (CPAP) therapy might correct metabolic abnormalities in glucose metabolism. It is assumed that this depends on therapy compliance to CPAP. On the other hand, there are also hints in the literature that type 2 diabetes per se might induce sleep apnea, especially in patients with autonomic neuropathy. Pathophysiological considerations open up new insights into that problem. Based on the current scientific data, clinicians have to be aware of the relations between the two diseases, both from the sleep medical and the diabetological point of view. The paper summarizes the most important issues concerning the different associations of OSA and type 2 diabetes.

APAP impact on metabolic syndrome in obstructive sleep apnea patients

PURPOSE

Prevalence of metabolic syndrome (MS) in obstructive sleep apnea (OSA) patients is high. The effect of autoadjusting positive airway pressure (APAP) on MS remains unclear. This study aimed to determine the prevalence of MS in OSA patients before and 6 months after APAP, and to identify potential determinants of metabolic status change.

METHODS

Seventy-four male patients with moderate to severe OSA were enrolled. MS diagnosis was established according to the National Cholesterol Education Program/Adult Treatment Panel III. APAP was prescribed to all patients.

RESULTS

In the studied population, mean age was 55.9 years (SD 10.7 years), median body mass index (BMI), Epworth sleepiness scale (ESS), and respiratory disturbance index (RDI) were 33.4 kg/m(2) (interquartile range (IQR) 8.4 kg/m(2)), 12.0 (IQR 8.0), and 46.9/h (IQR 33.6/h), respectively. Prevalence of MS before and 6 months after APAP was 63.5% and 47.3%, respectively, and this difference was statistically significant (p = 0.004). In the subgroup of patients with MS at baseline (n = 47), 14 did not present MS after APAP. In these patients, a significant negative association with RDI (p = 0.016) and a positive association with percent of total days of usage (p = 0.014) were found. Blood pressure (p = 0.018) and serum triglycerides (p = 0.001) had a statistically significant reduction during this period. In patients that still had MS, 22.2% presented a reduction of the number of MS criteria.

CONCLUSIONS

After 6 months, APAP reduced the prevalence of MS, mainly in patients with less severe OSA and with a better therapeutic compliance. Blood pressure and serum triglycerides reduction contributed to this metabolic status change.

Do sleep disorders and associated treatments impact glucose metabolism?

Over the past decade substantial evidence has accumulated implicating disorders of sleep in the pathogenesis of various metabolic abnormalities. This review, which is based on workshop discussions that took place at the 6th annual meeting of the International Sleep Disorders Forum: The Art of Good Sleep 2008 and a systematic literature search, provides a critical analysis of the available evidence implicating sleep disorders such as obstructive sleep apnoea (OSA), insomnia, short or long-term sleep duration and restless legs syndrome as potential risk factors for insulin resistance, glucose intolerance, type 2 diabetes mellitus and the metabolic syndrome. The review also highlights the evidence on whether treatment of specific sleep disorders can decrease metabolic risk. In total, 83 published reports were selected for inclusion. Although several studies show clear associations between sleep disorders and altered glucose metabolism, causal effects and the underlying pathophysiological mechanisms involved have not been fully elucidated. OSA appears to have the strongest association with insulin resistance, glucose intolerance, type 2 diabetes and the metabolic syndrome. There are, however, limited data supporting the hypothesis that effective treatment of sleep disorders, including OSA, has a favourable effect on glucose metabolism. Large randomized trials are thus required to address whether improvement of sleep quality and quantity can curtail excess metabolic risk. Research is also required to elucidate the mechanisms involved and to determine whether the effects of treatment for sleep disorders on glucose metabolism are dependent on the specific patient factors, the type of disorder and the duration of metabolic dysfunction. In conclusion, there is limited evidence on whether sleep disorders alter glucose metabolism and whether treatment can reduce the excess metabolic risk.

Risk factors and treatment for obstructive sleep apnea amongst obese children and adults

PURPOSE OF REVIEW

The purpose of this review is to summarize the evidence for the association between obesity and obstructive sleep apnea (OSA), as well as predisposing risk factors and treatment strategies for OSA amongst obese patients.

RECENT FINDINGS

Recent findings highlight a number of factors including sex, age, upper airway structure and ethnicity, which may predispose patients to OSA when obese. Both invasive and noninvasive weight-reduction strategies also show positive signs of being an effective means to reduce or remediate OSA amongst obese adults and children.

SUMMARY

In view of recent findings, a direct association between body mass and upper airway obstruction should be viewed with caution. Obesity may play a more significant role in the predisposition to OSA amongst particular subgroups of the population, such as adults, and those with particular craniofacial and upper airway morphology. Healthcare prioritization and requirements may be more substantial for such groups. Further, commonly used treatment methods for OSA (such as adenotonsillectomy for children and continuous positive airway pressure for adults) may be less effective for obese individuals. Weight-reduction strategies appear important for an optimal outcome, and such strategies may be more or less invasive depending on the severity of obesity, OSA or both, and other patient complications.

Neck circumference as a measure of central obesity: associations with metabolic syndrome and obstructive sleep apnea syndrome beyond waist circumference

BACKGROUND & AIMS

To investigate the relationship of neck circumference (NC) to metabolic syndrome (MetS) and obstructive sleep apnea syndrome (OSAS) and whether it adds information to that provided by waist circumference.

METHODS

Cross-sectional analysis of a population sample of 1,912 men and women, aged 55.1 +/- 12 years, representative of Turkish adults. MetS was identified based on modified criteria of the ATP-III, OSAS when habitual snoring and episodes of apnea were combined with another relevant symptom.

RESULTS

NC measured 36.7 (+/- 3.5) cm in the total sample. It was significantly correlated with numerous risk factors, above all body mass index and waist girth (r > or = 0.6), homeostatic model-assessed insulin resistance, blood pressure and, inversely, with smoking status and sex hormone-binding globulin. Sex- and age-adjusted NC was associated significantly with MetS, at a 2-3-fold increased likelihood for 1 standard deviation (SD) increment. After further adjustment for waist circumference and smoking status, a significant residual odds ratio (OR, 1.13 [95% CI 1.08; 1.19]) persisted, corresponding to ORs of 1.53 and 1.27 in males and females, respectively, for 1 SD increment. Even when adjusted for all MetS components, a residual OR (1.08 [95% CI 1.000; 1.17]) remained. Sex- and age-adjusted NC was associated significantly also with OSAS in genders combined, independent of waist girth, yielding an added OR of 1.3 for 1 SD increment.

CONCLUSIONS

NC contributes to MetS likelihood beyond waist circumference and the MetS components. Regarding association with OSAS, NC is of greater value than WC among Turkish men, not women.

Metabolic effects of the obstructive sleep apnea syndrome and cardiovascular risk

The obstructive sleep apnea syndrome (OSAS) is characterized by collapse of the upper airway during sleep, recurring apneas, intermittent hypoxemia and daytime somnolence. OSAS is often associated with obesity, and its prevalence is expected to rise due to the obesity epidemics worldwide. OSAS is associated with increased cardiovascular risk which appears to be normalized by treatment with nasal continuous positive airway pressure (nCPAP) during sleep, suggesting an independent role of OSAS in accelerating atherosclerosis. Insulin resistance (IR) and the metabolic syndrome (MetS) are often found in OSAS patients, but the relative role played by OSAS and obesity is still unclear. Both OSAS and MetS may exert negative synergistic effects on the cardiovascular system through multiple mechanisms (hypoxemia, sleep disruption, activation of the sympathetic nervous system, inflammatory activation). Besides nCPAP treatment, pharmacologic interventions to treat obesity and the MetS could improve cardiovascular prevention in OSAS.

Obstructive sleep apnea and type 2 diabetes: interacting epidemics

Type 2 diabetes is a major public health concern with high morbidity, mortality, and health-care costs. Recent reports have indicated that the majority of patients with type 2 diabetes also have obstructive sleep apnea (OSA). There is compelling evidence that OSA is a significant risk factor for cardiovascular disease and mortality. Rapidly accumulating data from both epidemiologic and clinical studies suggest that OSA is also independently associated with alterations in glucose metabolism and places patients at an increased risk of the development of type 2 diabetes. Experimental studies in humans and animals have demonstrated that intermittent hypoxia and reduced sleep duration due to sleep fragmentation, as occur in OSA, exert adverse effects on glucose metabolism. Based on the current evidence, clinicians need to address the risk of OSA in patients with type 2 diabetes and, conversely, evaluate the presence of type 2 diabetes in patients with OSA. Clearly, there is a need for further research, using well-designed studies and long-term follow-up, to fully demonstrate a causal role for OSA in the development and severity of type 2 diabetes. In particular, future studies must carefully consider the confounding effects of central obesity in examining the link between OSA and alterations in glucose metabolism. The interactions among the rising epidemics of obesity, OSA, and type 2 diabetes are likely to be complex and involve multiple pathways. A better understanding of the relationship between OSA and type 2 diabetes may have important public health implications.

[Obstructive sleep apnea syndrome and upper airway resistance syndrome. Gender-related differences]

BACKGROUND

The aim of this study was to assess potential gender-related differences in the clinical presentation and polysomnographic parameters of patients with obstructive sleep apnea syndrome (OSAS) and upper airway resistance syndrome (UARS).

PATIENTS AND METHODS

The polysomnographic variables and medical histories of 165 women with OSAS and 66 women with UARS from two sleep disorder clinics, presenting consecutively between 2000 and 2006 were retrospectively analyzed. These women were matched with an identical number of men, presenting during the same time frame, by diagnostic category (UARS/OSAS), age, and BMI.

RESULTS

The relative percentage of women diagnosed with UARS varied dependent on their menopausal status. Postmenopausal women presented significantly less frequently with UARS than pre- and perimenopausal women. The adjusted odds ratio for a diagnosis of OSAS vs UARS was 5.5 (CI: 2.3;13.2; P=0.001) compared to premenopausal women. UARS women had a 30 min higher subjective sleep need than UARS men (8.2+/-1.1 vs 7.7+/-1.1 h/night; P=0.028). UARS women consumed significantly more prescription drugs than UARS men (P=0.017), and presented with a significantly lower quality of life score than their male counterparts (P=0.021). The quantitative snoring measure during sleep did not indicate significant gender differences between diagnostic categories and gender.

CONCLUSIONS

Clinical presentation and polysomnographic parameters in patients with OSAS and UARS show distinct gender-related differences. These differences should be considered when patients present with signs and symptoms of OSAS or UARS.