Obstructive sleep apnea and type 2 diabetes: interacting epidemics

Sex differences in sleep apnea predictors and outcomes from home sleep apnea testing

STUDY OBJECTIVES

To evaluate sex differences in predictors of obstructive sleep apnea (OSA) as per outcomes from home sleep apnea testing.

DESIGN

This was a retrospective analysis of a large repository of anonymous test results and pretest risk factors for OSA.

SETTING AND PATIENTS

A total of 272,705 patients were referred for home sleep apnea testing from a variety of clinical practices for suspected sleep disordered breathing across North America from 2009 to 2013.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

Predictors of OSA (apnea hypopnea index4%≥5) were evaluated by multiple logistic regression; sex differences were evaluated by interaction effects. Middle age was the single most robust predictor of OSA for both sexes and was particularly foretelling for females (P<0.001) even after controlling for measures of adiposity and medical conditions. Females over the age of 45 years were much more likely to have OSA compared to their younger counterparts (78.7% vs 42.5%, respectively; odds ratio: 5.0) versus males (88.1% vs 68.8%, respectively; odds ratio: 3.4). Snoring, although more frequently reported by males, was similarly predictive of OSA for both sexes. Witnessed apneas and measures of adiposity were better predictors of OSA for males than females. Insomnia, depression, and use of sleep medication, although more commonly reported in females, did not predict OSA. Hypertension, although equally reported by both sexes, performed better as a predictor in females (P<0.001), even after controlling for age, measures of adiposity, and other medical conditions. Diabetes, heart disease, stroke, and sleepiness did not contribute unique variance in OSA in adjusted models.

CONCLUSION

This study found that males and females report different symptoms upon clinical evaluation for suspected sleep apnea, with some of the "classic" OSA features to be more common in and robustly predictive for males. The finding that advancing age uniquely and robustly predicted OSA in females reinforces our understanding that age-related changes in sex hormones play a role in the development and/or manifestation of sleep disordered breathing. Need exists for sex-specific prediction models and quantification of menopausal status in OSA screening tools.

Long sleep duration and afternoon napping are associated with higher risk of incident diabetes in middle-aged and older Chinese: the Dongfeng-Tongji cohort study

BACKGROUND

In this study, we investigated the independent and combined effects of sleep duration and afternoon napping on the risk of incident diabetes among a cohort of middle-aged and older Chinese adults.

METHODS

Information of sleep and napping was obtained by questionnaires during face-to-face interviews. We categorized sleep duration into <7 h, 7∼<8 h (reference), 8∼<9 h, 9∼<10 h, and ≥ 10 h. Afternoon napping was divided into no napping (0 min) (reference), 1-30 min, 31-60 min, 61-90 min, and > 90 min. Cox proportional hazard regression models were used.

RESULTS

Compared with referential sleeping group, subjects sleeping ≥10 h had a 42% higher risk of developing diabetes. The HR was 1.28 for napping > 90 min when compared with no napping. These associations were more pronounced in individuals without hypertension. Combined effects of long sleep duration and afternoon napping were further identified. Individuals with both sleep duration ≥ 10 h and napping > 60 min had a 72% higher risk of incident diabetes than those with sleeping 7∼<8 h and napping 0 min (all above p < 0.05).

CONCLUSIONS

Both long sleep duration and afternoon napping were independently and jointly associated with higher risk of incident diabetes. Key messages Sleep duration was associated with diabetes, but whether it is a real cause of incident diabetes especially in Chinese still remains to be elucidated. The association of afternoon napping and diabetes was not consistent and definite, we clarified this association in a large prospective study. Long sleep duration and afternoon napping were independently and jointly associated with higher risk of incident diabetes.

Psoriasis: new comorbidities

Psoriasis is a chronic inflammatory disease associated with several comorbidities. A few decades ago, it was considered an exclusive skin disease but today it is considered a multisystem disease. It is believed that 73% of psoriasis patients have at least one comorbidity. Studies have demonstrated the association of psoriasis with inflammatory bowel disease, uveitis, psychiatric disorders, metabolic syndrome and its components and cardiovascular diseases. The systemic inflammatory state seems to be the common denominator for all these comorbidities. This work aims at presenting a review of the current literature on some new comorbidities that are associated with psoriasis as osteoporosis, obstructive sleep apnea and chronic obstructive pulmonary disease. While there is still controversy, many studies already point to a possible bone involvement in patients with psoriasis, especially in the male group, generally less affected by osteoporosis. Psoriasis and chronic obstructive pulmonary disease present some risk factors in common as obesity, smoking and physical inactivity. Besides, both diseases are associated with the metabolic syndrome. These factors could be potential confounders in the association of the two diseases. Further prospective studies with control of those potential confounders should be developed in an attempt to establish causality. Existing data in the literature suggest that there is an association between obstructive sleep apnea and psoriasis, but studies performed until now have involved few patients and had a short follow-up period. It is, therefore, premature to assert that there is indeed a correlation between these two diseases.

Do discrimination, residential school attendance and cultural disruption add to individual-level diabetes risk among Aboriginal people in Canada?

Background

Aboriginal peoples in Canada (First Nations, Metis and Inuit) are experiencing an epidemic of diabetes and its complications but little is known about the influence of factors attributed to colonization. The purpose of this study was to investigate the possible role of discrimination, residential school attendance and cultural disruption on diabetes occurrence among First Nations adults.

Methods

This 2012/13 cross sectional survey was conducted in two Saskatchewan First Nations communities comprising 580 households and 1570 adults. In addition to self-reported diabetes, interviewer-administered questionnaires collected information on possible diabetes determinants including widely recognized (e.g. age, sex, lifestyle, social determinants) and colonization-related factors. Clustering effect within households was adjusted using Generalized Estimating Equations.

Results

Responses were obtained from 874 (55.7 %) men and women aged 18 and older living in 406 (70.0 %) households. Diabetes prevalence was 15.8 % among women and 9.7 % among men. In the final models, increasing age and adiposity were significant risk factors for diabetes (e.g. OR 8.72 [95 % CI 4.62; 16.46] for those 50+, and OR 8.97 [95 % CI 3.58; 22.52] for BMI 30+) as was spending most time on-reserve. Residential school attendance and cultural disruption were not predictive of diabetes at an individual level but those experiencing the most discrimination had a lower prevalence of diabetes compared to those who experienced little discrimination (2.4 % versus 13.6 %; OR 0.11 [95 % CI 0.02; 0.50]). Those experiencing the most discrimination were significantly more likely to be married and to have higher incomes.

Conclusions

Known diabetes risk factors were important determinants of diabetes among First Nations people, but residential school attendance and cultural disruption were not predictive of diabetes on an individual level. In contrast, those experiencing the highest levels of discrimination had a low prevalence of diabetes. Although the reasons underlying this latter finding are unclear, it appears to relate to increased engagement with society off-reserve which may lead to an improvement in the social determinants of health. While this may have physical health benefits for First Nations people due to improved socio-economic status and other undefined influences, our findings suggest that this comes at a high emotional price.

Management of obstructive sleep apnea in edentulous patients: an overview of the literature

Purpose

A high prevalence of obstructive sleep apnea (OSA) is seen in edentulous individuals. Treatment options for edentulous OSA patients however are limited with continuous positive airway pressure therapy (CPAP) remaining the current therapy of choice. As CPAP is associated with high non-adherence rates and oral appliance therapy requiring sufficient dentition, there is a clinical need for effective treatment strategies aimed at edentulous OSA patients. The purpose of this study was to present a thorough overview of the literature regarding (1) the effects of nocturnal denture wearing on OSA, (2) the outcomes of oral appliance therapy, and (3) surgical treatment in edentulous OSA patients.

Methods

A computer-assisted literature search was performed in the MEDLINE database on “edentulism” and “obstructive sleep apnea.” The search yielded a total of 34 original articles.

Results

A total of 20 studies were included after exclusion of non-relevant, duplicate, and non-English publications, comprising 4 randomized clinical trials, 12 case reports, and 4 cohort or cross-sectional studies. The outcomes of these studies were addressed in detail concerning nocturnal wearing of dentures, oral appliance therapy, and surgical treatment.

Conclusion

Currently, there is no consensus in the literature on the effects of nocturnal wearing of dentures on OSA. Several studies report the successful use of oral appliance therapy, including implant-retained mandibular advancement devices (MADs), in selected cases of edentulous patients with varying stages of OSA. Little evidence is available regarding outcomes of surgical procedures in edentulous patients. Based on the results of this literature overview, the paucity of effective evidence-based treatment strategies for edentulous OSA patients indicates the further need of clinical studies to improve clinical management.

The impact of sleep on age-related sarcopenia: Possible connections and clinical implications

Sarcopenia is a geriatric condition that comprises declined skeletal muscle mass, strength and function, leading to the risk of multiple adverse outcomes, including death. Its pathophysiology involves neuroendocrine and inflammatory factors, unfavorable nutritional habits and low physical activity. Sleep may play a role in muscle protein metabolism, although this hypothesis has not been studied extensively. Reductions in duration and quality of sleep and increases in prevalence of circadian rhythm and sleep disorders with age favor proteolysis, modify body composition and increase the risk of insulin resistance, all of which have been associated with sarcopenia. Data on the effects of age-related slow-wave sleep decline, circadian rhythm disruptions and obstructive sleep apnea (OSA) on hypothalamic-pituitary-adrenal (HPA), hypothalamic-pituitary-gonadal (HPG), somatotropic axes, and glucose metabolism indicate that sleep disorder interventions may affect muscle loss. Recent research associating OSA with the risk of conditions closely related to the sarcopenia process, such as frailty and sleep quality impairment, indirectly suggest that sleep can influence skeletal muscle decline in the elderly. Several protein synthesis and degradation pathways are mediated by growth hormone (GH), insulin-like growth factor-1 (IGF-1), testosterone, cortisol and insulin, which act on the cellular and molecular levels to increase or reestablish muscle fiber, strength and function. Age-related sleep problems potentially interfere intracellularly by inhibiting anabolic hormone cascades and enhancing catabolic pathways in the skeletal muscle. Specific physical exercises combined or not with nutritional recommendations are the current treatment options for sarcopenia. Clinical studies testing exogenous administration of anabolic hormones have not yielded adequate safety profiles. Therapeutic approaches targeting sleep disturbances to normalize circadian rhythms and sleep homeostasis may represent a novel strategy to preserve or recover muscle health in older adults. Promising research results regarding the associations between sleep variables and sarcopenia biomarkers and clinical parameters are required to confirm this hypothesis.

Usefulness of fetuin-A to predict risk for cardiovascular disease among patients with obstructive sleep apnea

Patients with obstructive sleep apnea (OSA) are at increased risk for cardiovascular diseases (CVDs). Fetuin-A, a novel hepatokine, has been associated with the metabolic syndrome (MetS), insulin resistance, and type 2 diabetes mellitus, all of which are highly prevalent in patients with OSA and associated with increased CVD risk. The goal of this study was to determine whether fetuin-A could be involved in the pathogenesis of CVD risk in patients with OSA, through relations of fetuin-A with MetS components and/or insulin resistance. Overweight or obese, nondiabetic volunteers (n = 120) were diagnosed with OSA by in-laboratory nocturnal polysomnography. Steady-state plasma glucose concentrations derived during the insulin suppression test were used to quantify insulin-mediated glucose uptake; higher steady-state plasma glucose concentrations indicated greater insulin resistance. Fasting plasma fetuin-A and lipoprotein concentrations were measured. Whereas neither the prevalence of MetS nor the number of MetS components was associated with tertiles of fetuin-A concentrations, the lipoprotein components of MetS, triglycerides and high-density lipoprotein cholesterol, increased (p <0.01) and decreased (p <0.05), respectively, across fetuin-A tertiles. Additionally, comprehensive lipoprotein analysis revealed that very low density lipoprotein (VLDL) particles and VLDL subfractions (VLDL1+2 and VLDL3) were increased across fetuin-A tertiles. In contrast, neither insulin resistance nor sleep measurements related to OSA were found to be modified by fetuin-A concentrations. In conclusion, abnormalities of lipoprotein metabolism, but not MetS or insulin resistance per se, may represent a mechanism by which fetuin-A contributes to increased CVD risk in patients with OSA.

Interrelationships between obesity, obstructive sleep apnea syndrome and cardiovascular risk in obese adolescents

BACKGROUND/OBJECTIVES

Obstructive sleep apnea syndrome (OSAS) may be a cardiovascular disease (CVD) risk factor independently of obesity in adults. Pediatric studies have associated OSAS with endothelial dysfunction, but few studies have examined relationships between OSAS and macrovascular sequelae. Our objective was to examine OSAS's independent contribution to macrovascular CVD risk measures in obese adolescents.

SUBJECTS/METHODS

This cross-sectional observational study was conducted at Children's Hospital of Philadelphia Clinical Research and Academic Sleep Centers, and University of Pennsylvania Vascular Research Unit. Thirty-one obese non-diabetic adolescents underwent anthropometric measurements, overnight polysomnography, fasting laboratory draw and cardiovascular imaging. Cardiovascular outcome measures included maximal carotid intima-media thickness (cIMTmax), a measure of carotid structural changes, and carotid-femoral pulse wave velocity (CFPWV), an aortic stiffness measure whose relationship vis-à-vis OSAS in children has not been previously examined. Carotid diameter and augmentation index (AIx, measuring central pressure augmentation from wave reflections) were assessed. Potential confounding variables examined included blood pressure, lipoproteins, high-sensitivity C-reactive protein, insulin and glucose.

RESULTS

The apnea hypopnea index, a primary OSAS measure, was not associated with cIMTmax, carotid diameter, CFPWV or AIx. body mass index (BMI) associated positively with cIMTmax (r=0.52, P=0.006) and CFPWV (r=0.45, P=0.01). Mean asleep end-tidal CO2 was negatively associated with carotid diameter (r=-0.63, P<0.0005). Insulin levels were negatively associated with AIx (r=-0.53, P=0.02).

CONCLUSIONS

OSAS did not predict carotid structural changes or arterial stiffness independently of BMI in obese adolescents. Higher insulin levels associated with lower central pressure wave augmentation. Finally, long-term hypercapnia may predispose to carotid narrowing.

Abnormalities of lipoprotein concentrations in obstructive sleep apnea are related to insulin resistance

STUDY OBJECTIVE

Prevalence of cardiovascular disease (CVD) is increased in patients with obstructive sleep apnea (OSA), possibly related to dyslipidemia in these individuals. Insulin resistance is also common in OSA, but its contribution to dyslipidemia of OSA is unclear. The study's aim was to define the relationships among abnormalities of lipoprotein metabolism, clinical measures of OSA, and insulin resistance.

DESIGN

Cross-sectional study. OSA severity was defined by the apnea-hypopnea index (AHI) during polysomnography. Hypoxia measures were expressed as minimum and mean oxygen saturation, and the oxygen desaturation index. Insulin resistance was quantified by determining steady-state plasma glucose (SSPG) concentrations during the insulin suppression test. Fasting plasma lipid/lipoprotein evaluation was performed by vertical auto profile methodology.

SETTING

Academic medical center.

PARTICIPANTS

107 nondiabetic, overweight/obese adults.

MEASUREMENTS AND RESULTS

Lipoprotein particles did not correlate with AHI or any hypoxia measures, nor were there differences noted by categories of OSA severity. By contrast, even after adjustment for age, sex, and BMI, SSPG was positively correlated with triglycerides (r = 0.30, P < 0.01), very low density lipoprotein (VLDL) and its subclasses (VLDL1+2) (r = 0.21-0.23, P < 0.05), and low density lipoprotein subclass 4 (LDL4) (r = 0.30, P < 0.01). SSPG was negatively correlated with high density lipoprotein (HDL) (r = -0.38, P < 0.001) and its subclasses (HDL2 and HDL3) (r = -0.32, -0.43, P < 0.01), and apolipoprotein A1 (r = -0.33, P < 0.01). Linear trends of these lipoprotein concentrations across SSPG tertiles were also significant.

CONCLUSIONS

Pro-atherogenic lipoprotein abnormalities in obstructive sleep apnea (OSA) are related to insulin resistance, but not to OSA severity or degree of hypoxia. Insulin resistance may represent the link between OSA-related dyslipidemia and increased cardiovascular disease risk.

Combined effect of obstructive sleep apnea and chronic smoking on cognitive impairment

OBJECTIVES

Little is known about combined effect of obstructive sleep apnea (OSA) and chronic smoking on cognitive impairment. We aimed to determine whether smoking synergizes with OSA in deteriorating cognitive function and whether smoking cessation contributes to cognitive benefits.

METHODS

One hundred and eighteen male patients were enrolled in the study and asked to complete neurocognitive function tests including Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), clock drawing test (CDT), and verbal fluency test (VFT). Variables of those neurocognitive function tests were analyzed with two factors: OSA and smoking.

RESULTS

After adjustment of potential confounding factors, an OSA-by-smoking interaction was found in CDT-C scores and a main smoking effect were showed in MoCA scores. Smoking patients with OSA had the worst performance in the four tests compared with the other three groups (smoking patients without OSA, non-smoking patients with and without OSA). Ex-smokers with OSA tended to perform better than current smokers, but still worse than never-smokers with OSA in those tests.

CONCLUSION

The results suggested that the coexistence of OSA and chronic smoking resulted in more pronounced cognitive deficits than either factor along. Smoking cessation may benefit cognitive function to some extents in patients with OSA.

Glucose homeostasis during short-term and prolonged exposure to high altitudes

Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis.

Quantification of diabetes comorbidity risks across life using nation-wide big claims data

Despite substantial progress in the study of diabetes, important questions remain about its comorbidities and clinical heterogeneity. To explore these issues, we develop a framework allowing for the first time to quantify nation-wide risks and their age- and sex-dependence for each diabetic comorbidity, and whether the association may be consequential or causal, in a sample of almost two million patients. This study is equivalent to nearly 40,000 single clinical measurements. We confirm the highly controversial relation of increased risk for Parkinson's disease in diabetics, using a 10 times larger cohort than previous studies on this relation. Detection of type 1 diabetes leads detection of depressions, whereas there is a strong comorbidity relation between type 2 diabetes and schizophrenia, suggesting similar pathogenic or medication-related mechanisms. We find significant sex differences in the progression of, for instance, sleep disorders and congestive heart failure in diabetic patients. Hypertension is a highly sex-sensitive comorbidity with females being at lower risk during fertile age, but at higher risk otherwise. These results may be useful to improve screening practices in the general population. Clinical management of diabetes must address age- and sex-dependence of multiple comorbid conditions.

Characterization of sleep breathing pattern in patients with type 2 diabetes: sweet sleep study

BACKGROUND

Although sleep apnea-hypopnea syndrome (SAHS) is highly prevalent in patients with type 2 diabetes (T2D), it is unknown whether or not subjects with and without T2D share the same sleep breathing pattern.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional study in patients with SAHS according to the presence (n = 132) or not (n = 264) of T2D. Both groups were matched by age, gender, BMI, and waist and neck circumferences. A subgroup of 125 subjects was also matched by AHI. The exclusion criteria included chronic respiratory disease, alcohol abuse, use of sedatives, and heart failure. A higher apnea hypopnea index (AHI) was observed in T2D patients [32.2 (10.2-114.0) vs. 25.6 (10.2-123.4) events/hours; p = 0.002). When sleep events were evaluated separately, patients with T2D showed a significant increase in apnea events [8.4 (0.1-87.7) vs. 6.3 (0.0-105.6) e/h; p = 0.044), as well as a two-fold increase in the percentage of time spent with oxygen saturation <90% [15.7 (0.0-97.0) vs. 7.9 (0.0-95.6) %; <0.001)], higher rates of oxygen desaturation events, and also higher daily sleepiness [7.0 (0.0-21.0) vs. 5.0 (0.0-21.0); p = 0.006)] than subjects without T2D. Significant positive correlations between fasting plasma glucose and AHI, the apnea events, and CT90 were observed. Finally, multiple linear regression analyses showed that T2D was independently associated with AHI (R2 = 0.217), the apnea index (R2 = 0.194), CT90 (R2 = 0.222), and desaturation events.

CONCLUSIONS/SIGNIFICANCE

T2D patients present a different pattern of sleep breathing than subject without diabetes. The most important differences are the severity of hypoxemia and the number of apneas whereas the incidence of hypopnea episodes is similar.

Intermittent hypoxemia and OSA: implications for comorbidities

OSA is a common chronic disorder that is associated with significant morbidity and mortality including cardiovascular, metabolic, and neurocognitive disease and increased cancer-related deaths. OSA is characterized by recurrent episodes of apneas and hypopneas associated with repetitive episodes of intermittent hypoxemia, intrathoracic pressure changes, and arousals. Intermittent hypoxemia (IH) is now being recognized as a potential major factor contributing to the pathogenesis of OSA-related comorbidities. OSA-related high-frequency IH is characterized by cycles of hypoxemia with reoxygenation that is distinctly different than sustained low-frequency hypoxia and contributes to ischemia-reperfusion injury. Data from both animal and human studies support mechanistic links between IH and its adverse impact at the tissue level. IH promotes oxidative stress by increased production of reactive oxygen species and angiogenesis, increased sympathetic activation with BP elevation, and systemic and vascular inflammation with endothelial dysfunction that contributes to diverse multiorgan chronic morbidity and mortality affecting cardiovascular disease, metabolic dysfunction, cognitive decline, and progression of cancer. Data from observational studies in large population groups also support the role for hypoxia in the pathogenesis of OSA comorbidity. Treatment with CPAP to reverse OSA-related symptoms and comorbidities has been shown to provide variable benefit in some but not all patient groups. Early treatment with CPAP makes intuitive sense to promote maximal functional recovery and minimize residual injury. More studies are needed to determine the interacting effects of IH and obesity, differential effects of both short-term and long-term hypoxemia, and the effect of CPAP treatment.

Use of oximetry as a screening tool for obstructive sleep apnea: a case study in Taiwan

Obstructive sleep apnea (OSA) is a relatively common disease in the general population. Patients with OSA have a high risk of various comorbid medical diseases. Polysomnography (PSG) is the current gold standard for diagnosing OSA but is time consuming and expensive. This study aims to identify a sensitive screening parameter that can be used by clinicians to determine the time of referral for PSG examination in Taiwan. Eighty-seven patients, including 67 males and 20 females, were included in this study. We divided the patients into two groups: training data (n = 58) and testing group (n = 29). Pearson χ(2) test was used to perform bivariate analysis, and a decision tree was used to build a model. The decision model selected the frequency of desaturation > 4% per hour (DI4) as the indicator of OSA influence. The testing data accuracy of the C4.5 decision tree was 82.80%. External data were also used to validate the model reliability. The accuracy of the external data was 95.96%. Approximately one-third of patients with DI4 between 11 and 33 suffered from OSA. This population requires further diagnosis. Oximetry is an important and widely available screening method in Taiwan. This study proposes the need for PSG referral if DI4 is between 11 and 33.

Comorbidity of diabetes and obstructive sleep apnea in hospitalized patients

Obstructive sleep apnea (OSA) and type 2 diabetes are two morbidities commonly encountered in the hospitalized setting. Both diseases will present with an array of complications if not managed in a timely, competent manner. However, a growing body of evidence suggests a link between these two pathologies. It is our hope that through careful review of the literature, we may generate heightened awareness of the OSA/diabetes comorbidity. Through better understanding of these conditions and their interactions, we may insure efficient management in the clinical setting and prevent exacerbation of common complications.

Serum advanced glycation end products are associated with insulin resistance in male nondiabetic patients with obstructive sleep apnea

PURPOSE

Advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic vascular complications. Recently, growing evidence has shown that AGEs could be involved in the pathogenesis of insulin resistance. It has also been suggested that circulating AGE are associated with insulin resistance in nondiabetic patients. This study investigated whether serum AGEs levels are associated with insulin resistance in nondiabetic patients with obstructive sleep apnea (OSA).

METHODS

A total of 139 male nondiabetic patients with OSA were recruited for participation in the study. Serum AGE levels were examined using an enzyme-linked immunosorbent assay. Insulin resistance was determined using the homeostasis model assessment index (HOMA-IR).

RESULTS

There was a significant correlation between serum AGEs and the apnea-hypopnea index (AHI) (r = 0.281, p = 0.014), duration of SaO₂ < 90% (r = 0.267, p = 0.018), minimum SaO₂ (r = -0.188, p = 0.046), high-sensitivity C-reactive protein (hsCRP) (r = 0.274, p = 0.012), and HOMA-IR (r = 0.303, p < 0.001). Multiple regression analysis showed that serum AGEs (p = 0.011), AHI (p = 0.024), waist circumference (p = 0.040), and hsCRP (p = 0.046) were independently associated with HOMA-IR (R(2) = 0.392). In addition, the strength of the correlation between serum AGEs and HOMA-IR was related to the severity of OSA.

CONCLUSIONS

The present study indicated that serum AGE levels were associated with insulin resistance in male nondiabetic patients with OSA. These findings suggest that AGEs may play a role in insulin resistance in OSA and may also be a biomarker for patients with OSA with high risk of developing type 2 diabetes.

Metabolic and glycemic sequelae of sleep disturbances in children and adults

The prevalence of obesity in adults and children has increased greatly in the past three decades, as have metabolic sequelae, such as insulin resistance and type 2 diabetes mellitus (T2DM). Sleep disturbances are increasingly recognized as contributors to this widespread epidemic in adults, and data are emerging in children as well. The categories of sleep disturbances that contribute to obesity and its glycemic co-morbidities include the following: (1) alterations of sleep duration, chronic sleep restriction and excessive sleep; (2) alterations in sleep architecture; (3) sleep fragmentation; (4) circadian rhythm disorders and disruption (i.e., shift work); and (5) obstructive sleep apnea. This article reviews current evidence supporting the contributions that these sleep disorders play in the development of obesity, insulin resistance, and T2DM as well as possibly influences on glycemic control in type 1 diabetes, with a special focus on data in pediatric populations.

Insulin resistance using HOMA model in obstructive sleep apnea: a cross sectional study

BACKGROUND AND OBJECTIVES

Obstructive sleep apnea (OSA) is a common disease affecting middle-aged patients and is associated with significant cardiovascular, cerebrovascular, and metabolic complications. Current evidences show inconclusive association between OSA and insulin resistance (IR). This study aims to examine the possible correlation between OSA parameters and IR.

DESIGN AND SETTINGS

This was a cross-sectional study to examine the association between OSA parameters and IR using homeostasis model assessment (HOMA) on patients who underwent polysomnogram (PSG) in a tertiary center between March 2011 and March 2012 (1 year).

PATIENTS AND METHODS

A total of 62 patients underwent PSG within the study period, of which 16 patients were excluded due to abnormal fasting blood sugar. Information on patients' medical illnesses, medications, and Epworth sleepiness scale (ESS) was obtained. Patients' body mass index (BMI), neck circumference, and waist circumference (WC) were measured. Blood samples were collected after 8 hours of fasting to measure HOMA-IR value. Overnight PSG was performed for all patients. Data was recorded and analyzed using SPSS, version 12.0 (SPSS Inc, Chicago, USA).

RESULTS

The prevalence of IR in OSA patients was 64.3%. There was significant correlation between OSA parameters (apnea-hypopnea index, ESS, BMI, and WC) and HOMA-IR with correlation coefficient of 0.529, 0.224, 0.261, and 0.354, respectively.

CONCLUSION

A linear correlation exists between OSA parameters and IR concluding a definite causal link between OSA and IR. IR screening is recommended in severe OSA patients.

Urinary proteomics in obstructive sleep apnoea and obesity

BACKGROUND

Obstructive sleep apnoea (OSA) is a common complication of obesity and can have a substantial negative impact on a patient's quality of life and risk of cardiovascular disease. The aim of this case-control study was to undertake discovery profiling of urinary peptides using capillary electrophoresis-mass spectrometry (CE-MS) in obese subjects with and without OSA, without a history of coronary artery disease.

MATERIALS AND METHODS

Urinary samples were analysed by CE-MS. Body composition and blood pressure measurements were recorded. Overnight polysomnography was conducted to confirm or refute OSA. OSA patients were naïve to continuous positive airway pressure treatment.

RESULTS

Sixty-one subjects with OSA (age 47 ± 9 years, BMI 43 ± 8 kg/m(2)) and 31 controls (age 49 ± 10 years, BMI 40 ± 5 kg/m(2)) were studied; P = ns for age and BMI. Apnoea-hypopnoea Index was higher in patients with OSA (24 ± 18·6) than controls without OSA (non-OSA) (2·6 ± 1·1; P < 0·0001). Metabolic syndrome was present in 35 (57%) of those with OSA compared with 4 (13%) of controls (P < 0·0001). Twenty-four polypeptides were candidates for differential distribution (P < 0·01), although these differences did not reach significance after multiple testing. Sequences were determined for eight peptides demonstrating origins from collagens and fibrinogen alpha.

CONCLUSIONS

In this study, we report for the first time, urinary proteomic profile analyses using CE-MS in OSA and non-OSA obese groups. The differences in urinary proteomic profiles prior to adjustment for multiple testing, with increased metabolic syndrome in obese OSA subjects, suggest that there may be a role for CE-MS in characterising urinary profiles in severely obese populations with OSA.

Carotid body, insulin, and metabolic diseases: unraveling the links

The carotid bodies (CB) are peripheral chemoreceptors that sense changes in arterial blood O2, CO2, and pH levels. Hypoxia, hypercapnia, and acidosis activate the CB, which respond by increasing the action potential frequency in their sensory nerve, the carotid sinus nerve (CSN). CSN activity is integrated in the brain stem to induce a panoply of cardiorespiratory reflexes aimed, primarily, to normalize the altered blood gases, via hyperventilation, and to regulate blood pressure and cardiac performance, via sympathetic nervous system (SNS) activation. Besides its role in the cardiorespiratory control the CB has been proposed as a metabolic sensor implicated in the control of energy homeostasis and, more recently, in the regulation of whole body insulin sensitivity. Hypercaloric diets cause CB overactivation in rats, which seems to be at the origin of the development of insulin resistance and hypertension, core features of metabolic syndrome and type 2 diabetes. Consistent with this notion, CB sensory denervation prevents metabolic and hemodynamic alterations in hypercaloric feed animal. Obstructive sleep apnea (OSA) is another chronic disorder characterized by increased CB activity and intimately related with several metabolic and cardiovascular abnormalities. In this manuscript we review in a concise manner the putative pathways linking CB chemoreceptors deregulation with the pathogenesis of insulin resistance and arterial hypertension. Also, the link between chronic intermittent hypoxia (CIH) and insulin resistance is discussed. Then, a final section is devoted to debate strategies to reduce CB activity and its use for prevention and therapeutics of metabolic diseases with an emphasis on new exciting research in the modulation of bioelectronic signals, likely to be central in the future.

Self-reported sleep disturbance is associated with Alzheimer's disease risk in men

OBJECTIVE

To study the association between self-reported sleep disturbances and dementia risk.

METHODS

Self-reported sleep disturbances and established risk factors for dementia were measured in men at ages 50 (n = 1574) and 70 (n = 1029) years. Dementia incidence was determined by reviewing their patient history between ages 50 and 90 years. In addition, plasma levels of β-amyloid (Aβ) peptides 1-40 and 1-42 were measured at ages 70, 77, and 82 years.

RESULTS

Cox regression demonstrated that men with self-reported sleep disturbances had a higher risk of developing dementia (+33%) and Alzheimer's disease (AD, +51%) than men without self-reported sleep disturbances (both P < .05). Binary logistic regression showed the increased risk for both dementia (+114%) and AD (+192%) were highest when sleep disturbance was reported at age 70 years (both P < .001). No group differences were found in Aβ levels.

CONCLUSION

Improving sleep quality may help reduce the neurodegenerative risk in older men.

Glucose sensing by carotid body glomus cells: potential implications in disease

The carotid body (CB) is a key chemoreceptor organ in which glomus cells sense changes in blood O2, CO2, and pH levels. CB glomus cells have also been found to detect hypoglycemia in both non-primate mammals and humans. O2 and low-glucose responses share a common final pathway involving membrane depolarization, extracellular calcium influx, increase in cytosolic calcium concentration, and neurotransmitter secretion, which stimulates afferent sensory fibers to evoke sympathoadrenal activation. On the other hand, hypoxia and low glucose induce separate signal transduction pathways. Unlike O2 sensing, the response of the CB to low glucose is not altered by rotenone, with the low glucose-activated background cationic current unaffected by hypoxia. Responses of the CB to hypoglycemia and hypoxia can be potentiated by each other. The counter-regulatory response to hypoglycemia by the CB is essential for the brain, an organ that is particularly sensitive to low glucose. CB glucose sensing could be altered in diabetic patients, particularly those under insulin treatment, as well as in other medical conditions such as sleep apnea or obstructive pulmonary diseases, where chronic hypoxemia presents with plastic modifications in CB structure and function. The current review will focus on the following main aspects: (1) the CB as a low glucose sensor in both in vitro and in vivo models; (2) molecular and ionic mechanisms of low glucose sensing by glomus cells, (3) the interplay between low glucose and O2 sensing in CB, and (4) the role of CB low glucose sensing in the pathophysiology of cardiorespiratory and metabolic diseases, and how this may serve as a potential therapeutic target.

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 apnea and progression of coronary artery calcium: the multi-ethnic study of atherosclerosis study

Background

Obstructive sleep apnea (OSA) is a common condition associated with cardiovascular disease. Its potential effect on progression of subclinical atherosclerosis is not well understood. We tested the hypothesis that self‐reported OSA is associated with progression of coronary artery calcium (CAC). We also evaluated whether traditional cardiovascular risk factors accounted for the association.

Methods and Results

In the Multi‐Ethnic Study of Atherosclerosis (MESA) prospective cohort, we studied 2603 participants who at baseline (2002–2004) completed a sleep questionnaire and underwent coronary computed tomography (CT) and, then 8 years later (2010–2011), a repeat coronary CT. Participants were categorized by symptoms of habitual snoring or reported physician diagnosis of OSA. At baseline, 102 (3.9%) reported diagnosed OSA; 666 (25.6%) reported diagnosed habitual snoring; and 1835 (70.5%) reported neither habitual snoring nor OSA (“normal”). At baseline, CAC prevalence was highest among those with OSA but similar for those with and without habitual snoring. During 8 years of follow‐up, greater progression of CAC was observed among those with OSA versus normal (mean increase of 204.2 versus 135.5 Agatston units; P=0.01), after accounting for demographics, behaviors, and body habitus. Modest attenuation was observed after adjustment for cardiovascular risk factors (188.7 versus 138.8; P=0.06). CAC progression among habitual snorers was similar to that observed in the normal group.

Conclusions

OSA was associated with CAC score progression after adjustment for demographics, behaviors, and body mass index. However, the association was not significant after accounting for cardiovascular risk factors, which may mediate the association between OSA and CAC.

Associations between self-reported sleep duration and sleeping disorder with concentrations of fasting and 2-h glucose, insulin, and glycosylated hemoglobin among adults without diagnosed diabetes

BACKGROUND

There is limited information from population-based investigations of the associations between sleep duration and sleep disorders and parameters of glucose homeostasis. The objective of the present study was to examine cross-sectional associations between sleep duration and sleep disordered breathing with concentrations of insulin, fasting and 2-h glucose, and HbA1c.

METHODS

Data from 11 815 adults aged ≥20 years without diagnosed diabetes (5002 with an oral glucose tolerance test) from the National Health and Nutrition Examination Survey 2005-2010 were used. Information about sleep duration (2005-2010) and sleep apnea and sleep-disordered breathing (2005-2008) was obtained via questionnaire.

RESULTS

An estimated 36.0% of participants reported sleeping ≤6 h/night, 62.0% reported sleeping 7-9 h/night, and 2.0% reported sleeping ≥10 h/night. In 2005-2008, 33.0% reported snoring ≥5 nights per week, 5.9% reported they snorted, gasped, or stopped breathing ≥5 nights/week, and 4.2% reported sleep apnea. Sleep duration was significantly associated with fasting concentrations of insulin and concentrations of HbA1c only in models that did not adjust for body mass index (BMI). Concentrations of fasting and 2-h glucose were significantly associated with sleep duration in models that adjusted only for age. Snoring frequency was positively associated with concentrations of insulin and HbA1c. Frequency of snorting or stopping breathing and sleep apnea status were associated with concentrations of insulin and of HbA1c only when BMI was not accounted for.

CONCLUSION

In a representative sample of US adults, concentrations of insulin and HbA1c were significantly associated with short sleep duration, possibly mediated by BMI.

New frontiers in obstructive sleep apnoea

OSA (obstructive sleep apnoea), the most common respiratory disorder of sleep, is caused by the loss of upper airway dilating muscle activity during sleep superimposed on a narrow upper airway. This results in recurrent nocturnal asphyxia. Termination of these events usually requires arousal from sleep and results in sleep fragmentation and hypoxaemia, which leads to poor quality sleep, excessive daytime sleepiness, reduced quality of life and numerous other serious health consequences. Furthermore, patients with untreated sleep apnoea are at an increased risk of hypertension, stroke, heart failure and atrial fibrillation. Although there are many predisposing risk factors for OSA, including male gender, endocrine disorders, use of muscle relaxants, smoking, fluid retention and increased age, the strongest risk factor is obesity. The aim of the present review is to focus on three cutting-edge topics with respect to OSA. The section on animal models covers various strategies used to simulate the physiology or the effects of OSA in animals, and how these have helped to understand some of the underlying mechanisms of OSA. The section on diabetes discusses current evidence in both humans and animal models demonstrating that intermittent hypoxia and sleep fragmentation has a negative impact on glucose tolerance. Finally, the section on cardiovascular biomarkers reviews the evidence supporting the use of these biomarkers to both measure some of the negative consequences of OSA, as well as the potential benefits of OSA therapies.

Association between obstructive sleep apnea and deep vein thrombosis / pulmonary embolism: a population-based retrospective cohort study

BACKGROUND

Obstructive sleep apnea (OSA) is a major contributor to cardiovascular disease, and may cause severe morbidity and mortality. Recent studies have indicated that OSA patients exhibited elevated platelet activity, fibrinogen levels, and platelet aggregation.

OBJECTIVES

We investigated the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients diagnosed with OSA compared with age- and sex-matched unaffected people.

PATIENTS/METHODS

This longitudinal, nationwide, population-based cohort study was conducted using data from Taiwan National Health Insurance Research Database (NHIRD) recorded between January 2000 and December 2011. The study consisted of 3511 patients with OSA and 35110 matched comparison individuals. A Cox proportional hazard regression was used to compute the risk of DVT and PE in patients with OSA compared with those without OSA.

RESULTS

The DVT and PE risks were 3.50- and 3.97-fold higher (95% CI=1.83-6.69 and 1.85-8.51) respectively, in the OSA cohort than in the reference cohort after we adjusted for age, sex, and comorbidities.

CONCLUSION

This nationwide population-based cohort study indicates that patients with OSA exhibit a higher risk of subsequent DVT and PE.

Clinical effect of surgical correction for nasal pathology on the treatment of obstructive sleep apnea syndrome

Objectives

This study aimed to evaluate the hypothesis that relief of nasal obstruction in subjects with obstructive sleep apnea (OSA) would lead to reduce OSA severity and to discuss the available evidence on the clinical efficacy of nasal surgery as a treatment modality for OSA.

Study Design

Twenty-five subjects who had reduced patency of nasal cavity and narrowing of retroglossal or retropalatal airways were diagnosed with OSA and underwent nasal surgery, such as septoplasty or turbinoplasty to correct nasal pathologies. The effect of the surgery on nasal patency was quantified by measuring minimal cross-sectional area (MCA) using acoustic rhinometry. The watch-PAT-derived respiratory disturbance index (RDI), apnea and hypopnea index (AHI), lowest oxygen saturation, and valid sleep time were measured before and after nasal surgery.

Results

The present study shows that the AHI and RDI decreased significantly and the lowest oxygen saturation and valid sleep time rose after nasal surgery in 25 OSA subjects. In addition, a reduction in subjective symptoms was observed in subjects and mean MCA increased after nasal surgery. Fourteen subjects were classified as responders and 11 subjects as non-responders. Responders showed considerable improvement of their subjective symptoms and the AHI and RDI were significantly lower after surgery. We found that the changes between pre- and post-operative AHI and RDI values were minimal in 11 non-responders. However, daytime somnolence and REM sleep time improved after nasal surgery in non-responders.

Conclusions

Our study provides evidence that the surgical treatment of nasal pathology improves nasal airway patency and reduces OSA severity in 56% subjects. Furthermore, correction of nasal pathology appears to result in improved sleep quality in both responder and non-responders OSA subjects.

Simple snoring: not quite so simple after all?

Simple snoring (SS), in the absence of obstructive sleep apnoea (OSA), is a common problem, yet our understanding of its causes and consequences is incomplete. Our understanding is blurred by the lack of consistency in the definition of snoring, methods of assessment, and degree of concomitant complaints. Further, it remains contentious whether SS is independently associated with daytime sleepiness, or adverse health outcomes including cardiovascular disease and metabolic syndrome. Regardless of this lack of clarity, it is likely that SS exists on one end of a continuum, with OSA at its polar end. This possibility highlights the necessity of considering an otherwise 'annoying' complaint, as a serious risk factor for the development and progression of sleep apnoea, and consequent poor health outcomes. In this review, we: 1) highlight variation in prevalence estimates of snoring; 2) review the literature surrounding the distinctions between SS, upper airway resistance syndrome (UARS) and OSA; 3) present the risk factors for SS, in as far as it is distinguishable from UARS and OSA; and 4) describe common correlates of snoring, including cardiovascular disease, metabolic syndrome, and daytime sleepiness.

[Prevalence and predictors of obstructive sleep apnea in patients admitted for acute myocardial infarction]

BACKGROUND

Obstructive sleep apnea has been implicated in the pathogenesis and aggravation of coronary atherosclerosis. However, it remains underdiagnosed in cardiology practice.

AIM

The aim of this study was to determine the prevalence of obstructive sleep apnea and the predictors of severe sleep apnea in patients admitted for ST elevation myocardial infarction.

METHODS

This was a prospective study which has included 120 patients hospitalized for ST elevation myocardial infarction, from April 2011 to March 2012. All patients have undergone an overnight sleep study using a portable polygraphy device, in the 15 days following the acute coronary syndrome. The diagnostic of obstructive sleep apnea was considered as apnea-hypopnea index of ≥ 5 events per hour, severe sleep apnea was defined as apnea -hypopnea index of ≥ 30. Subjective daytime sleepiness was assessed by the Epworth sleepiness scale. All patients have had an oxygen saturation monitoring in the coronary care unit using a pulse oxymeter, before undergoing the sleep study.

RESULTS

The study population was made up of 102 men and 18 women. The mean age was 58 ± 12 years. Smoking was the major cardiovascular risk factor found in 72% of all patients, diabetes and hypertension were represented in 40% and 44% of the population, respectively. Eighty-seven percent of patients were admitted in the first 24 hours of symptom onset. A primary percutaneous coronary intervention was performed in 60% of cases while fibrinolysis was done in 10% of patients. The prevalence of obstructive sleep apnea was 79%. Mean apnea-hypopnea index was 15.76 ± 14.93 and severe form was diagnosed in 16% of all patients. Multivariate analysis showed that Epworth sleepiness score of ≥ 4 and nocturnal desaturation below 82% were independent predictive factors for severe obstructive sleep apnea.

CONCLUSION

Prevalence of obstructive sleep apnea was very high in patients admitted for acute myocardial infarction. Epworth sleepiness score of ≥ 4 and nocturnal desaturation below 82% were independent predictive factors for severe form of sleep apnea.

Role of the carotid body chemoreceptors in baroreflex control of blood pressure during hypoglycaemia in humans

Activation of the carotid body chemoreceptors with hypoxia alters baroreceptor-mediated responses. We aimed to examine whether this relationship can be translated to other chemoreceptor stimuli (i.e. hypoglycaemia) by testing the following hypotheses: (i) activation of the carotid body chemoreceptors with hypoglycaemia would reduce spontaneous cardiac baroreflex sensitivity (sCBRS) in healthy humans; and (ii) desensitization of the carotid chemoreceptors with hyperoxia would restore sCBRS to baseline levels during hypoglycaemia. Ten young healthy adults completed two 180 min hyperinsulinaemic [2 mU (kg fat-free mass)(-1) min(-1)], hypoglycaemic (∼ 3.2 μmol ml(-1)) clamps, separated by at least 1 week and randomized to normoxia (arterial partial pressure of O2, 122 ± 10 mmHg) or hyperoxia (arterial partial pressure of O2, 424 ± 123 mmHg; to blunt activation of the carotid body glomus cells). Changes in heart rate, blood pressure, plasma catecholamines, heart rate variability (HRV) and sCBRS were assessed. During hypoglycaemia, HRV and sCBRS were reduced (P < 0.05) and the baroreflex working range was shifted to higher heart rates. When hyperoxia was superimposed on hypoglycaemia, there was a greater reduction in blood pressure and a blunted rise in heart rate when compared with normoxic conditions (P < 0.05); however, there was no detectable effect of hyperoxia on sCBRS or HRV during hypoglycaemia (P > 0.05). In summary, hypoglycaemia-mediated changes in HRV and sCBRS cannot be attributed exclusively to the carotid chemoreceptors; however, the chemoreceptors appear to play a role in resetting the baroreflex working range during hypoglycaemia.

Epidemiology of Obstructive Sleep Apnea: a Population-based Perspective

This review summarizes the recent literature on the epidemiology of adult obstructive sleep apnea (OSA) from various population-based studies. Despite methodologic differences, comparisons have yielded similar prevalence rates of the OSA syndrome in various geographic regions and amongst a number of ethnic groups. Risk factors for OSA including obesity, aging, gender, menopause, and ethnicity are analyzed. We also provide discussion on adverse medical conditions associated with OSA including hypertension, stroke, congestive heart failure, coronary artery disease, cardiovascular mortality, insulin resistance, and neurocognitive dysfunction. Finally with the progression of the global obesity epidemic, we focus on the economic health care burden of OSA and the importance of recognizing the largely undiagnosed OSA population with emphasis on strategies to improve access to diagnostic resources.

Affective brain areas and sleep-disordered breathing

The neural damage accompanying the hypoxia, reduced perfusion, and other consequences of sleep-disordered breathing, found in obstructive sleep apnea, heart failure, and congenital central hypoventilation syndrome (CCHS), appears in areas that serve multiple functions, including emotional drives to breathe, and involve systems that serve affective, cardiovascular, and breathing roles. The damage, assessed with structural magnetic resonance imaging (MRI) procedures, shows tissue loss or water content and diffusion changes indicative of injury, and impaired axonal integrity between structures; damage is preferentially unilateral. Functional MRI responses in affected areas also are time- or amplitude-distorted to ventilatory or autonomic challenges. Among the structures injured are the insular, cingulate, and ventral medial prefrontal cortices, as well as cerebellar deep nuclei and cortex, anterior hypothalamus, caudal raphé, ventrolateral medulla, portions of the basal ganglia and, in CCHS, the locus coeruleus. Caudal raphé and locus coeruleus injury have the potential to modify serotonergic and adrenergic modulation of upper airway and arousal characteristics, as well as affective drive to breathe. Since both axons and gray matter show injury, the consequences to function, especially to autonomic, cognitive, and mood regulation, are major. Several of the affected rostral sites mediate aspects of dyspnea, especially in CCHS, while others participate in initiation of inspiration after central breathing pauses, and the medullary injury can impair baroreflex and breathing control. The ancillary injury associated with sleep-disordered breathing to central structures can elicit multiple other distortions in cardiovascular, cognitive, and emotional functions in addition to effects on breathing regulation.

Clinical outcomes and cost-effectiveness of continuous positive airway pressure to manage obstructive sleep apnea in patients with type 2 diabetes in the U.K

OBJECTIVE

To assess clinical outcomes and cost-effectiveness of using continuous positive airway pressure (CPAP) to manage obstructive sleep apnea (OSA) in patients with type 2 diabetes (T2D) from the perspective of the U.K.'s National Health Service (NHS).

RESEARCH DESIGN AND METHODS

Using a case-control design, 150 CPAP-treated patients with OSA and T2D were randomly selected from The Health Improvement Network (THIN) database (a nationally representative database of patients registered with general practitioners in the U.K.) and matched with 150 OSA and T2D patients from the same database who were not treated with CPAP. The total NHS cost and outcomes of patient management in both groups over 5 years and the cost-effectiveness of CPAP compared with no CPAP treatment were estimated.

RESULTS

Using CPAP was associated with significantly lower blood pressure at 5 years and increasingly lower HbA1c levels over 5 consecutive years compared with untreated OSA patients. At 5 years, the HbA1c level in the CPAP-treated group was 8.2% (66.0 mmol/mol) vs. 12.1% (108.4 mmol/mol) in the control group (P < 0.03). Use of CPAP significantly increased patients' health status by 0.27 quality-adjusted life years (QALYs) per patient over 5 years (P < 0.001) and NHS management costs by £4,141 per patient over 5 years; the cost per QALY gained with CPAP was £15,337.

CONCLUSIONS

Initiating treatment with CPAP in OSA patients with T2D leads to significantly lower blood pressure and better controlled diabetes and affords a cost-effective use of NHS resources. These observations have the potential for treatment modification if confirmed in a prospective study.

The use of portable monitoring for sleep apnea diagnosis in adults

Due to increasing demand for sleep services, there has been growing interest in ambulatory models of care for patients with obstructive sleep apnea (OSA). The implementation of alternative approaches to the current management by full polysomnography (PSG) in the sleep laboratory is necessary for diagnosing this syndrome due to the high cost of full-night PSG. A good alternative option for OSA diagnosis is portable monitoring (PM), which is known for its accuracy, ease of management and lower cost when compared with full PSG. PM has not been well validated for OSA diagnosis in patients with medical comorbidities or in elderly individuals and children. PM may be recommended as an alternative method to PSG for patients with high clinical risk for OSA. In the present review, we describe the use of PM for OSA diagnosis and evaluate the current progress, costs, limitations and applications of these devices in various groups of patients, particularly for patients with comorbid diseases.

Association between excessive daytime sleepiness and severe hypoglycemia in people with type 2 diabetes: the Edinburgh Type 2 Diabetes Study

OBJECTIVE

Sleep-disordered breathing and sleepiness cause metabolic, cognitive, and behavioral disturbance. Sleep-disordered breathing is common in type 2 diabetes, a condition that requires adherence to complex dietary, behavioral, and drug treatment regimens. Hypoglycemia is an important side effect of treatment, causing physical and psychological harm and limiting ability to achieve optimal glycemic control. We hypothesized that sleep disorder might increase the risk of hypoglycemia through effects on self-management and glucose regulation.

RESEARCH DESIGN AND METHODS

People with type 2 diabetes (n = 898) completed questionnaires to assess sleep-disordered breathing, daytime sleepiness, and occurrence of severe hypoglycemia.

RESULTS

Subjects who scored highly on the Epworth Sleepiness Scale were significantly more likely to have suffered from severe hypoglycemia. This was a significant predictor of severe hypoglycemia in regression analysis including the variables age, sex, duration of diabetes, HbA1c, BMI, and treatment type.

CONCLUSIONS

Daytime sleepiness may be a novel risk factor for hypoglycemia.

Are diabetic patients being screened for sleep related breathing disorder?

Prevalence of both diabetes mellitus and obstructive sleep apnea (OSA) is high among general population. Both of these conditions are associated with significant morbidity. OSA affects approximately 25% of men and 9% of women, and its prevalence is even higher among obese, Hispanics, African American and diabetic patients. Diabetes on the other hand besides having high prevalence in general population has even higher prevalence among ethnic populations as Hispanics and African American. Despite the availability of several simple screening tools for OSA, as Berlin questionnaire, STOP-BANG questionnaire, NAMES Criteria, the utility for screening of OSA among the diabetic population remains marginal. This in turn can lead to significant morbidity and complications related to OSA as well as worsening of diabetes mellitus and increase in diabetic complications due to untreated sleep related breathing disorder. It is therefore imperative for the primary care giver to screen for OSA among the diabetic population as a part of their routine evaluation to prevent worsening of diabetes, and its cardiovascular, renal, ophthalmologic and neurological complications.

Intermittent hypoxia impairs glucose homeostasis in C57BL6/J mice: partial improvement with cessation of the exposure

OBJECTIVES

Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued.

INTERVENTIONS

C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed.

RESULTS

Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted.

CONCLUSIONS

Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism.

Symptoms of sleep disordered breathing and risk of cancer: a prospective cohort study

STUDY OBJECTIVES

Sleep disordered breathing (SDB) has been associated with oxidative stress, inflammation, and altered hormonal levels, all of which could affect the risk of cancer. The aim of the study is to examine if symptoms of SDB including snoring, breathing cessations, and daytime sleepiness affect the incidence of total cancer and subtypes of cancer.

DESIGN

Prospective cohort study.

SETTING

The third wave (1991-1993) of the Copenhagen City Heart Study.

PARTICIPANTS

There were 8,783 men and women in whom cancer had not been previously diagnosed.

MEASUREMENTS AND RESULTS

Participants answered questions about snoring and breathing cessations in 1991-1993, whereas information about daytime sleepiness based on the Epworth Sleepiness Scale was collected in a subset of the participants (n = 5,894) in 1998. First-time incidence of cancer was followed until December 2009 in a nationwide cancer register. We found no overall association between symptoms of SDB and incident cancer. Yet, in the small group with high daytime sleepiness, we observed a surprisingly higher cancer incidence (hazard ratio = 4.09; 95% CI 1.58-10.55) in persons younger than 50 years. We also found a higher risk of virus/immune-related cancers (2.73; 1.27-5.91) and alcohol-related cancers (4.92; 1.45-16.76) among persons with daytime sleepiness. More SDB symptoms were associated with a higher risk of smoking-related cancers (Ptrend: 0.04). Apart from these findings there were no clear associations between symptoms of sleep disordered breathing and cancer subtypes.

CONCLUSION

We found very limited evidence of relationship between symptoms of sleep disordered breathing and incidence of cancer.

Impairment of pancreatic β-cell function by chronic intermittent hypoxia

NEW FINDINGS

What is the central question of this study? Periodic decreases in arterial blood O2 or chronic intermittent hypoxia (CIH) is a hallmark feature of sleep apnoea patients. Despite a large body of clinical evidence linking sleep disordered breathing with apnoeas to diabetes, the causal relationships between CIH and β-cell function and the underlying molecular mechanisms have not been established. What is the main finding and its importance? In a rodent model, we show that mitochondrial oxidative stress generated by CIH leads to pancreatic β-cell dysfunction manifested by augmented basal insulin secretion, insulin resistance, defective proinsulin processing and impaired glucose-stimulated insulin secretion. The results of the present study provide evidence for direct effects of CIH on β-cell function, which may be an underlying molecular mechanism contributing to the development of type 2 diabetes among sleep apnoea patients. Breathing disorders with recurrent apnoea produce periodic decreases in arterial blood O2, i.e. chronic intermittent hypoxia (CIH). Recurrent apnoea patients and CIH-exposed rodents exhibit several co-morbidities, including diabetes. However, the effects of CIH on pancreatic β-cell function are not known. In the present study, we investigated pancreatic β-cell function in C57BL6 mice exposed to 30 days of CIH. Compared with control animals, the CIH-exposed mice exhibited elevated levels of fasting plasma insulin but comparable glucose levels and higher homeostasis model assessment, indicating insulin resistance. Pancreatic β-cell morphology was unaltered in CIH-exposed mice. Insulin content was decreased in CIH-exposed β-cells, and this effect was associated with increased proinsulin levels. The mRNA and protein levels of the enzyme prohormone convertase 1, which converts proinsulin to insulin, were downregulated in CIH-treated islets. More importantly, glucose-stimulated insulin secretion was impaired in CIH-exposed mice and in isolated islets. Mitochondrial levels of reactive oxygen species (ROS) were elevated in CIH-exposed pancreatic islets. Treatment of mice with mito-tempol, a scavenger of mitochondrial ROS, during exposure to CIH prevented the augmented insulin secretion and restored the proinsulin and homeostasis model assessment values to control levels. These results demonstrate that CIH leads to pancreatic β-cell dysfunction, manifested by augmented basal insulin secretion, insulin resistance, defective proinsulin processing, impaired glucose-stimulated insulin secretion and increased mitochondrial ROS, which mediate the effects of CIH on pancreatic β-cell function.