Nocturnal intermittent hypoxia and the development of type 2 diabetes: the Circulatory Risk in Communities Study (CIRCS)

Independent relationship between sleep apnea-specific hypoxic burden and glucolipid metabolism disorder: a cross-sectional study

OBJECTIVES

Obstructive sleep apnea (OSA) is associated with abnormal glucose and lipid metabolism. However, whether there is an independent association between Sleep Apnea-Specific Hypoxic Burden (SASHB) and glycolipid metabolism disorders in patients with OSA is unknown.

METHODS

We enrolled 2,173 participants with suspected OSA from January 2019 to July 2023 in this study. Polysomnographic variables, biochemical indicators, and physical measurements were collected from each participant. Multiple linear regression analyses were used to evaluate independent associations between SASHB, AHI, CT90 and glucose as well as lipid profile. Furthermore, logistic regressions were used to determine the odds ratios (ORs) for abnormal glucose and lipid metabolism across various SASHB, AHI, CT90 quartiles.

RESULTS

The SASHB was independently associated with fasting blood glucose (FBG) (β = 0.058, P = 0.016), fasting insulin (FIN) (β = 0.073, P < 0.001), homeostasis model assessment of insulin resistance (HOMA-IR) (β = 0.058, P = 0.011), total cholesterol (TC) (β = 0.100, P < 0.001), total triglycerides (TG) (β = 0.063, P = 0.011), low-density lipoprotein cholesterol (LDL-C) (β = 0.075, P = 0.003), apolipoprotein A-I (apoA-I) (β = 0.051, P = 0.049), apolipoprotein B (apoB) (β = 0.136, P < 0.001), apolipoprotein E (apoE) (β = 0.088, P < 0.001) after adjustments for confounding factors. Furthermore, the ORs for hyperinsulinemia across the higher SASHB quartiles were 1.527, 1.545, and 2.024 respectively, compared with the lowest quartile (P < 0.001 for a linear trend); the ORs for hyper-total cholesterolemia across the higher SASHB quartiles were 1.762, 1.998, and 2.708, compared with the lowest quartile (P < 0.001 for a linear trend) and the ORs for hyper-LDL cholesterolemia across the higher SASHB quartiles were 1.663, 1.695, and 2.316, compared with the lowest quartile (P < 0.001 for a linear trend). Notably, the ORs for hyper-triglyceridemia{1.471, 1.773, 2.099} and abnormal HOMA-IR{1.510, 1.492, 1.937} maintained a consistent trend across the SASHB quartiles.

CONCLUSIONS

We found SASHB was independently associated with hyperinsulinemia, abnormal HOMA-IR, hyper-total cholesterolemia, hyper-triglyceridemia and hyper-LDL cholesterolemia in Chinese Han population. Further prospective studies are needed to confirm that SASHB can be used as a predictor of abnormal glycolipid metabolism disorders in patients with OSA.

TRIAL REGISTRATION

ChiCTR1900025714 { http://www.chictr.org.cn/ }; Prospectively registered on 6 September 2019; China.

Detection of episodic nocturnal hypercapnia in patients with neurodegenerative disorders

PURPOSE

Episodic nocturnal hypercapnia (eNH) in transcutaneous carbon dioxide pressure (PtcCO2) corresponding to rapid eye movement sleep hypoventilation is a useful biomarker for detecting nocturnal hypoventilation. However, the relationship between eNH and neurodegenerative diseases with sleep-related breathing disorders (SRBDs) is unknown. The aim of this study was to evaluate the relationship between eNH and nocturnal hypoventilation in neurodegenerative diseases.

METHODS

Patients with neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), Parkinson's disease, progressive supranuclear palsy, corticobasal syndrome, and idiopathic normal pressure hydrocephalus, were enrolled and received overnight PtcCO2 monitoring. The patients were divided into groups for eNH and sleep-associated hypoventilation (SH) prevalence analysis: A (ALS), B (MSA), and C (others).

RESULTS

Among 110 patients, twenty-three (21%) and 10 (9%) of the patients met eNH and SH criteria, respectively. eNH and SH were significantly more frequent in groups A and B than in C. The prevalence of SH in the patients with eNH was 39% whereas most of patients with SH (90%) presented with eNH. Among patients with daytime carbon dioxide pressure in arterial blood ≤ 45 mmHg, eNH frequency was 13%, whereas none of the patients met SH criteria. The frequency of noninvasive positive pressure ventilation after PtcCO2 monitoring was significantly higher in those with than without eNH.

CONCLUSIONS

eNH is common in patients with MSA and ALS who present with SRBD. eNH with overnight PtcCO2 monitoring is a useful biomarker to detect hypoventilation among neurodegenerative diseases with different SRBD mechanisms.

The pathogenesis of OSA-related hypertension: what are the determining factors?

Sleep-disordered breathing has a relatively high prevalence, which varies from 3-7% in males and from 2-5% in females in the adult population. Studies published in the literature have shown that sleep apnea is closely related to an increased risk of developing various pathologies, among which arterial hypertension stands out. The prevalence of hypertension in patients suffering from obstructive sleep apnea (OSA) ranges from 35-80% and appears to be related to OSA severity. Approximately 40-50% of patients affected by hypertension are also affected by OSA and this association seems to be stronger in young and middle-aged adults (<50 years of age). The primary objective of this narrative review is to provide an update on what are the main contributing comorbidities to the development of a hypertensive state in patients suffering from OSA, an independent risk factor for diurnal hypertension, implicated as a risk factor for the first stroke, recurrent stroke, and post-stroke mortality. There are a lot of factors that contribute to developing a hypertensive state in OSA patients, some more decisive, others less. More evidence from longitudinal studies is needed on the impact of OSA on cardiovascular risk in females, on the causal link between OSA and arterial hypertension or metabolic diseases, like diabetes and glucose intolerance, and the effect of different kinds of OSA treatment.

Nocturnal Intermittent Hypoxia and the Risk of Cardiovascular Disease among Japanese Populations: The Circulatory Risk in Communities Study (CIRCS)

AIMS

Information is limited about the influence of obstructive sleep apnea (OSA) on developing cardiovascular disease (CVD) among Asian community-dwelling populations. We examined the association between nocturnal intermittent hypoxia as a surrogate marker of OSA and the risk of CVD in a Japanese community-based cohort study.

METHODS

We used baseline surveys from 2000 to 2008 to study the cohort data of 5,313 residents from three Japanese communities who were between the ages of 40 and 74 years and initially free from ischemic heart disease and stroke. We assessed the number of 3% oxygen desaturation index (ODI) as the indicator of nocturnal intermittent hypoxia. We divided individuals into two groups depending on 3% ODI (3% ODI ≥ 5 or 3% ODI ＜5). Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD according to 3% ODI. Age, sex, body mass index, alcohol, and smoking were adjusted in the multivariable models.

RESULTS

During 12.8 years of the median follow-up with 66,796 person-years, 185 cases with CVD (115 stroke and 70 coronary heart disease [CHD]) were recorded. The multivariable HRs (95% CIs) were 1.49 (1.09-2.03), 2.13 (1.08-4.22), and 1.93 (1.16-3.19) for the 3% ODI ≥ 5 group versus the 3% ODI ＜5 group of developing CVD, lacunar infarction, and CHD, respectively.

CONCLUSIONS

Nocturnal intermittent hypoxia may increase the risk of developing lacunar infarction and CHD among community-dwelling Japanese populations. However, we could not find a significant risk of developing total stroke or stroke subtypes such as intraparenchymal hemorrhage, subarachnoid hemorrhage, and total ischemic stroke.

Causal associations of sleep apnea and snoring with type 2 diabetes and glycemic traits and the role of BMI

OBJECTIVE

Sleep apnea and snoring have been associated with type 2 diabetes, with BMI playing a role in the pathway, but the directions of causality are unclear. This study examined the causal associations of sleep apnea and snoring with type 2 diabetes while assessing the role of BMI using multiple genetic methods.

METHODS

Five genetic methods were used: two-sample; bidirectional univariable Mendelian randomization (MR) inverse variance-weighted (MR-IVW); multivariable MR-IVW; network MR; and latent causal variable method.

RESULTS

Compared with univariable MR-IVW, the odds ratio (95% CI) of type 2 diabetes for genetically predicted sleep apnea and snoring using the largest genome-wide association study decreased dramatically, from 1.61 (95% CI: 1.16-2.23) to 1.08 (95% CI: 0.59-1.97) and from 1.98 (95% CI: 1.25-3.13) to 1.09 (95% CI: 0.64-1.86) after adjustment for BMI. Network MR showed that BMI accounts for 67% and 62% of the total effect of sleep apnea and snoring on type 2 diabetes, respectively. The latent causal variable suggested that sleep apnea and snoring have no direct causal effect on type 2 diabetes.

CONCLUSIONS

These results first suggest that the associations of sleep apnea and snoring with type 2 diabetes were mainly driven by BMI. The possible indirect effects of sleep apnea and snoring on type 2 diabetes through BMI cannot be ruled out.

The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity

STUDY OBJECTIVES

To evaluate the impact of sleep-disordered breathing (SDB) on vascular, angiogenic and metabolic analytes in pregnancy.

METHODS

Participants with a body mass index ≥30 kg/m2 underwent polysomnography at 14-20 weeks gestation (visit 1). Participants with SDB (defined as an apnea-hypopnea index ≥5 events/h) were then enrolled in a separate trial. SDB-negative participants returned for a polysomnogram at 28-31 weeks (visit 2) and were recategorized as persistent-negative SDB or new-onset SDB. Mean arterial blood pressure, mean uterine artery Doppler pulsatility index, endoglin, soluble Feline McDonough Sarcoma-like tyrosine kinase 1, placental growth factor, and the homeostatic model assessment for insulin resistance were measured after each visit. Our primary outcome was a composite of uterine artery Doppler pulsatility index, soluble FMS-like tyrosine kinase 1/placental growth factor ratio, and homeostatic model assessment for insulin resistance. For secondary analyses, each outcome variable was analyzed independently.

RESULTS

A total of 242 and 130 participants completed visit 1 and visit 2, respectively. Newly diagnosed SDB was present in 37% of individuals at visit 1 and 31% of individuals at visit 2. No significant differences in our composite outcome vector were observed in individuals with and without SDB at either visit. In our secondary analysis, mean arterial blood pressure (88.7 ± 7.3 mm Hg vs 85.4 ± 7.1 mm Hg, P = .04) and fasting glucose (92.4 ± 15.2 mg/dL vs 86.6 ± 11.5 mg/dL, P = .05) were higher in participants with early pregnancy SDB. These associations were not observed for new-onset SDB. No associations were observed between uterine artery Doppler pulsatility index and angiogenic markers and SDB in pregnancy.

CONCLUSIONS

SDB in early pregnancy was not associated with our composite primary outcome but was associated with higher mean arterial blood pressure and fasting glucose. The pathophysiologic changes that occur in pregnant individuals with SDB and how they lead to an increased risk of preeclampsia and gestational diabetes remain poorly understood.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Sleep Disordered Breathing, Obesity and Pregnancy Study (SOAP); URL: https://clinicaltrials.gov/ct2/show/NCT02086448; Identifier: NCT02086448.

CITATION

Onslow ML, Wolsk J, Wisniewski S, et al. The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity. J Clin Sleep Med. 2023;19(1):97-109.

Obstructive sleep apnea, prediabetes, and progression of type 2 diabetes: A systematic review and meta-analysis

Aims/Introduction

Obstructive sleep apnea (OSA) is related to prediabetes and diabetes. Whether patients with OSA have a higher risk of prediabetes/diabetes remains unclear. We aimed to carry out a meta‐analysis of published studies to evaluate the relationships between OSA and prediabetes and diabetes, and the impact of the severity of OSA on diabetes.

Materials and Methods

The PubMed, EMBASE and Cochrane databases were searched from January 2011 to July 2021. The associations between OSA and impaired fasting glucose, impaired glucose tolerance, impaired glucose regulation and diabetes mellitus were analyzed. We estimated the pooled odds ratios using fixed or random effects models. We included 25 studies comprising a total of 154,948 patients with OSA and risk factors for prediabetes/diabetes (20 and 16, respectively) in the analysis.

Results

OSA was associated with a higher risk of impaired fasting glucose, impaired glucose tolerance, impaired glucose regulation and diabetes mellitus in the cohort studies and cross‐sectional studies. The pooled odds ratios were 2.34 (95% confidence interval [CI] 1.16–4.72), 1.58 (95% CI 1.15–2.15), 1.65 (95% CI 1.12–2.42), 2.15 (95% CI 1.68–2.75) and 3.62 (95% CI 2.75–4.75), respectively. Subgroup analyses were based on the proportions of men and women. The results showed that OSA was a risk factor, and there was no significant difference between the two groups. The risk of diabetes increased with the severity of OSA.

Conclusions

The risk of developing prediabetes and diabetes was higher in patients with OSA.

Sleep, circadian rhythms, and type 2 diabetes mellitus

Over the last 60 years we have seen a significant rise in metabolic disease, especially type 2 diabetes. In the same period, the emergence of electricity and artificial lighting has allowed our behavioural cycles to be independent of external patterns of sunlight. This has led to a corresponding increase in sleep deprivation, estimated to be about 1 hour per night, as well as circadian misalignment (living against the clock). Evidence from experimental animals as well as controlled human subjects have shown that sleep deprivation and circadian misalignment can both directly drive metabolic dysfunction, causing diabetes. However, the precise mechanism by which these processes contribute to insulin resistance remains poorly understood. In this article, we will review the new literature in the field and propose a model attempting to reconcile the experimental observations made. We believe our model will serve as a useful point of reference to understand how metabolic dysfunction can emerge from sleep or circadian rhythm disruptions, providing new directions for research and therapy.

Effect of nocturnal hypoxemia on glycemic control among diabetic Saudi patients presenting with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is a prevalent disease that is associated with an increased incidence of type II diabetes mellitus (DM) if left untreated. We aimed to determine the association between glycosylated hemoglobin (HbA1c) levels and both nocturnal hypoxemia and apnea-hypopnea index (AHI) among a Saudi patients with OSA.

METHODS

A cross-sectional study that enrolled 103 adult patients diagnosed with DM and confirmed to have OSA by full night attended polysomnography between 2018 and 2021. Those who presented with acute illness, chronic obstructive pulmonary disease (COPD)/restrictive lung diseases causing sleep-related hypoxemia, or no available HbA1c level within 6 months before polysomnography were excluded from the study. Univariate and multivariate linear regression analyses between HbA1c levels and parameters of interest were tested.

RESULTS

Sixty-seven (65%) of the studied population had uncontrolled DM (HbA1c ≥7%). In univariate regression analysis, there was a significant positive association between HbA1c, and sleep time spent with an oxygen saturation below 90% (T90), female gender, and body mass index (BMI) (p<0.05) but not AHI, or associated comorbidities (p>0.05). In the multivariate analysis, HbA1c was positively associated with increasing T90 (p<0.05), and ODI (p<0.05), but not with AHI (p>0.05).

CONCLUSION

Nocturnal hypoxemia could be an important factor affecting glycemic control in patients with OSA suffering from DM irrespective of the severity of both diseases.

Polysomnographic Phenotypes of Obstructive Sleep Apnea and Incident Type 2 Diabetes: Results from the DREAM Study

Rationale: Obstructive sleep apnea (OSA) is associated with cardiovascular disease and incident type 2 diabetes (T2DM). Seven OSA phenotypes, labeled on the basis of their most distinguishing polysomnographic features, have been shown to be differentially associated with incident cardiovascular disease. However, little is known about the relevance of polysomnographic phenotypes for the risk of T2DM. Objectives: To assess whether polysomnographic phenotypes are associated with incident T2DM and to compare the predictive value of baseline polysomnographic phenotypes with the Apnea-Hypopnea Index (AHI) for T2DM. Methods: The study included 840 individuals without baseline diabetes from a multisite observational U.S. veteran cohort who underwent OSA evaluation between 2000 and 2004, with follow-up through 2012. The primary outcome was incident T2DM, defined as no diagnosis at baseline and a new physician diagnosis confirmed by fasting blood glucose >126 mg/dL during follow-up. Relationships between the seven polysomnographic phenotypes (1. mild, 2. periodic limb movements of sleep [PLMS], 3. non-rapid eye movement and poor sleep, 4. rapid eye movement and hypoxia, 5. hypopnea and hypoxia, 6. arousal and poor sleep, and 7. combined severe) and incident T2DM were investigated using Cox proportional hazards regression and competing risk regression models with and without adjustment for baseline covariates. Likelihood ratio tests were conducted to compare the predictive value of the phenotypes with the AHI. Results: During a median follow-up period of 61 months, 122 (14.5%) patients developed incident T2DM. After adjustment for baseline sociodemographics, fasting blood glucose, body mass index, comorbidities, and behavioral risk factors, hazard ratios among persons with "hypopnea and hypoxia" and "PLMS" phenotypes as compared with persons with "mild" phenotype were 3.18 (95% confidence interval [CI], 1.53-6.61] and 2.26 (95% CI, 1.06-4.83) for incident T2DM, respectively. Mild OSA (5 ⩽ AHI < 15) (vs. no OSA) was directly associated with incident T2DM in both unadjusted and multivariable-adjusted regression models. The addition of polysomnographic phenotypes, but not AHI, to known T2DM risk factors greatly improved the predictive value of the computed prediction model. Conclusions: Polysomnographic phenotypes "hypopnea and hypoxia" and "PLMS" independently predict risk of T2DM among a predominantly male veteran population. Polysomnographic phenotypes improved T2DM risk prediction comared with the use of AHI.

Effects of Intermittent Hypoxia on Cytokine Expression Involved in Insulin Resistance

Sleep apnea syndrome (SAS) is a prevalent disorder characterized by recurrent apnea or hypoxia episodes leading to intermittent hypoxia (IH) and arousals during sleep. Currently, the relationship between SAS and metabolic diseases is being actively analyzed, and SAS is considered to be an independent risk factor for the development and progression of insulin resistance/type 2 diabetes (T2DM). Accumulating evidence suggests that the short cycles of decreased oxygen saturation and rapid reoxygenation, a typical feature of SAS, contribute to the development of glucose intolerance and insulin resistance. In addition to IH, several pathological conditions may also contribute to insulin resistance, including sympathetic nervous system hyperactivity, oxidative stress, vascular endothelial dysfunction, and the activation of inflammatory cytokines. However, the detailed mechanism by which IH induces insulin resistance in SAS patients has not been fully revealed. We have previously reported that IH stress may exacerbate insulin resistance/T2DM, especially in hepatocytes, adipocytes, and skeletal muscle cells, by causing abnormal cytokine expression/secretion from each cell. Adipose tissues, skeletal muscle, and the liver are the main endocrine organs producing hepatokines, adipokines, and myokines, respectively. In this review, we focus on the effect of IH on hepatokine, adipokine, and myokine expression.

Gender Differences in the Association Between Obstructive Sleep Apnea and Diabetes

OBJECTIVE

This study aimed to explore the association between obstructive sleep apnea (OSA) and diabetes in a Chinese population based on a cross-sectional analysis of patient data from a large tertiary care hospital in China and analyses whether there are any gender differences in this association.

METHODS

A total of 794 (615 men and 179 women) inpatients were involved in this study. Polysomnography (PSG) was used to diagnose OSA, and overnight PSG testing was performed on each subject included in this study. All study subjects were also diagnosed with whether they had diabetes by an endocrinologist in the hospital.

RESULTS

After adjusting for sex, age, smoking status, alcohol consumption and body mass index (BMI) groups, the results showed that the number of apnea-hypopnea index (AHI) events was a risk factor for diabetes, with a 9% (95% CI: 1-17%) increase in the risk of diabetes per unit increase, while subjects with higher (per unit increase) lowest oxygen saturation value monitored during the subject's sleep (LSaO2) with a 13% (95% CI: 4-22%) decrease in the risk of diabetes. Stratified analyses by gender, after adjustment, in men, OSA and its associated monitoring indicators were statistically significantly associated with diabetes [OR for severe OSA was 2.269 (95% CI: 1.164, 4.425), P=0.016, and OR for severe hypoxemia was 2.228 (95% CI: 1.145, 4.334), P=0.018], while not in women.

CONCLUSION

Our study found a significant association between OSA and diabetes in a Chinese clinical-based population as well as a dose-response relationship between the severity of AHI and severe hypoxemia (LSaO2 < 80%) and blood glucose, the association has gender difference and was only present significant association in men, which demonstrated that diabetes prevention and blood glucose screening and management should be enhanced for Chinese men with OSA.

Nocturnal Oxygen Saturation Parameters as Independent Risk Factors for Type 2 Diabetes Mellitus among Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a recognized independent risk factor for metabolic disorders, type 2 diabetes mellites (DM2) in particular. Therefore, the study aimed to assess the influence of nocturnal oxygen saturation parameters on the onset of DM2 among OSA patients. The study consisted of 549 participants, who underwent polysomnography examination. Based on apnea hypopnea index (AHI), 465 patients were diagnosed with OSA. One hundred and seven individuals had comorbid DM2. Cox regression models were used to assess the effect of oxygen saturation parameters on the onset of DM2. Classification and regression trees (CART) analysis was used to assess the onset of the DM2 in the study group in context of oxygen saturation variables. One-way Cox regression showed higher risk of earlier DM2 for increased values of BMI, AHI, decreased basal O₂ and O₂ nadir value, while lowered mean O₂ desaturation has not shown statistical significance. In the CART analysis, the following cut-off points 92.2%, 81.7%, 87.1% were determined for basal O₂, O₂ nadir and mean O₂ desaturation, respectively, with the first two parameters being statistically significant. Therefore, basal O₂ is independent from AHI, BMI and age is a risk factor of DM2 among OSA patients.

Interstitial lung disease and obstructive sleep apnea

Obstructive sleep apnea (OSA) is one of the most common comorbidities in patients with interstitial lung disease (ILD). Growing evidence highlights the significance of sleep disturbance on health outcomes in this population. The relationships between ILD and OSA are complex and possibly bidirectional, with multiple mechanisms postulated for the pathogenic and physiologic links. This review synthesizes current evidence and hypotheses regarding different aspects of the relationships between ILD and OSA, emphasizing the interactions between epidemiology, pathogenesis, and pathophysiology.

Psychological disturbances and their association with sleep disturbances in patients admitted for cardiovascular diseases

BACKGROUND

Depression and anxiety are common mental health problems that are strongly associated with sleep disturbances, according to community-based researches. However, this association has not been investigated among patients admitted for cardiovascular diseases (CVDs). We examined the prevalence of depression and anxiety in inpatients with various CVDs and their association with sleep disturbances.

MATERIALS AND METHODS

This cross-sectional study included 1294 patients hospitalized for CVDs in a Japanese university hospital were evaluated for their mental status using the Hospital Anxiety and Depression Scale (HADS), for sleep-disordered breathing (SDB) using pulse oximetry, and for sleep quality using the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

Patient characteristics were as below: mean age, 63.9±14.7 years; 25.7% female. Overall, 18.9% had depression (HADS-depression≥8) and 17.1% had anxiety (HADS-anxiety≥8). The presence of depression was associated with female sex, older age, higher plasma brain natriuretic peptide level, lower estimated glomerular filtration rate, and the prevalence of heart failure. Overall, 46.5% patients were categorized as having a poor sleep quality (PSQI>5), and 28.5% patients had SDB (3% oxygen desaturation index>15). Although depression and anxiety were not associated with SDB, they were independently associated with poor sleep quality (OR = 3.09, 95% CI 2.19-4.36; OR = 3.93, 95% CI 2.71-5.69, respectively).

CONCLUSIONS

Depression and anxiety were not uncommon in patients with CVDs. Poor sleep quality could be an important risk factor linked to psychological disturbances.

Obstructive sleep apnea and risk of type 2 diabetes mellitus: A systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

This meta-analysis was performed to quantitatively evaluate the dose-response association between obstructive sleep apnea (OSA) and risk of type 2 diabetes mellitus (T2DM).

METHODS

PubMed, Embase, and Web of Science were searched up to 12 December 2018 for articles that assessed the OSA-T2DM association. Random effects models were used to analyze the quantitative association between OSA and risk of T2DM. Restricted cubic splines were used to model the dose-response association between apnea-hypopnea index (AHI), used to assess the severity of OSA according to events/h, and risk of T2DM.

RESULTS

We included 16 cohort studies in our meta-analysis. During a median follow-up of 10.5 years (range: 3.0-22.0), 19 355 T2DM cases were reported among 338 912 study participants. The pooled relative risk of T2DM was 1.40 (95% CI, 1.32-1.48) for OSA in the binary meta-analysis and 1.08 (1.01-1.14) for each 5-event/h increase in AHI value. We found a positive linear association between OSA and T2DM risk.

CONCLUSIONS

Our dose-response meta-analysis revealed a linear association between OSA and T2DM.

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

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

Severity Indices for Obstructive Sleep Apnea Syndrome Reflecting Glycemic Control or Insulin Resistance

Objective We aimed to identify obstructive sleep apnea syndrome (OSAS) severity indices reflecting the anthropometric and metabolic characteristics of patients with OSAS. Methods A total of 76 patients with OSAS underwent nasal continuous positive airway pressure (nCPAP). We also investigated the effects of nCPAP on OSAS-associated muscle sympathetic nerve activity (MSNA), risk for cardiovascular diseases, and insulin secretion and sensitivity. Results Among the OSAS severity indices, HbA1c was significantly correlated with the apnea-hypopnea index, whereas HOMA-beta, HOMA-IR, and hepatic insulin resistance were significantly correlated with % SpO₂<90%, independent of age, gender, and body mass index (BMI). Burst incidence of MSNA was independently associated with only a 3% oxygen desaturation index. nCPAP therapy significantly lowered the OSAS severity indices and reduced the burst rate, burst incidence, and heart rate. Conclusion The OSAS severity indices reflecting apnea/hypopnea are associated with glycemic control, whereas those reflecting hypoxia, particularly % SpO₂<90%, are associated with hepatic insulin resistance independent of obesity. Both types of OSAS severity indices, especially the 3% oxygen desaturation index (reflecting intermittent hypoxia), are independently associated with MSNA, which is dramatically lowered with the use of nCPAP therapy. These findings may aid in interpreting each OSAS severity index and understanding the pathophysiology of OSAS in clinical settings.

Relationship Between Intermittent Hypoxia and Type 2 Diabetes in Sleep Apnea Syndrome

Sleep apnea syndrome (SAS) is a very common disease involving intermittent hypoxia (IH), recurrent symptoms of deoxygenation during sleep, strong daytime sleepiness, and significant loss of quality of life. A number of epidemiological researches have shown that SAS is an important risk factor for insulin resistance and type 2 diabetes mellitus (DM), which is associated with SAS regardless of age, gender, or body habitus. IH, hallmark of SAS, plays an important role in the pathogenesis of SAS and experimental studies with animal and cellular models indicate that IH leads to attenuation of glucose-induced insulin secretion from pancreatic β cells and to enhancement of insulin resistance in peripheral tissues and cells, such as liver (hepatocytes), adipose tissue (adipocytes), and skeletal muscles (myocytes). In this review, we focus on IH-induced dysfunction in glucose metabolism and its underlying molecular mechanisms in several cells and tissues related to glucose homeostasis.

Effects of Intermittent Hypoxia on Pulmonary Vascular and Systemic Diseases

Obstructive sleep apnea (OSA) causes many systemic disorders via mechanisms related to sympathetic nerve activation, systemic inflammation, and oxidative stress. OSA typically shows repeated sleep apnea followed by hyperventilation, which results in intermittent hypoxia (IH). IH is associated with an increase in sympathetic activity, which is a well-known pathophysiological mechanism in hypertension and insulin resistance. In this review, we show the basic and clinical significance of IH from the viewpoint of not only systemic regulatory mechanisms focusing on pulmonary circulation, but also cellular mechanisms causing lifestyle-related diseases. First, we demonstrate how IH influences pulmonary circulation to cause pulmonary hypertension during sleep in association with sleep state-specific change in OSA. We also clarify how nocturnal IH activates circulating monocytes to accelerate the infiltration ability to vascular wall in OSA. Finally, the effects of IH on insulin secretion and insulin resistance are elucidated by using an in vitro chamber system that can mimic and manipulate IH. The obtained data implies that glucose-induced insulin secretion (GIS) in pancreatic β cells is significantly attenuated by IH, and that IH increases selenoprotein P, which is one of the hepatokines, as well as TNF-α, CCL-2, and resistin, members of adipokines, to induce insulin resistance via direct cellular mechanisms. Clinical and experimental findings concerning IH give us productive new knowledge of how lifestyle-related diseases and pulmonary hypertension develop during sleep.

Epidemiological and pathophysiological evidence supporting links between obstructive sleep apnoea and Type 2 diabetes mellitus

Obstructive sleep apnoea (OSA) and Type 2 diabetes mellitus (T2DM) are common diseases. The global prevalence of OSA is between 2% and 7% in general population cohorts. The worldwide prevalence of T2DM among adults (aged 20-79 years) was estimated to be 6.4%. The concurrent presence of OSA and T2DM can be expected in the same patient, given their high prevalence and similar predisposition. We reviewed the overlapping pathophysiology of OSA and T2DM in this article.

Obstructive Sleep Apnea, Sleepiness, and Glycemic Control in Type 2 Diabetes

STUDY OBJECTIVES

Self-reported sleepiness is common in patients with obstructive sleep apnea (OSA) and is being increasingly recognized as an effect modifier of the association between OSA and cardiovascular outcomes. However, data on whether sleepiness modifies the association between OSA and glycemic outcomes are lacking. The current study sought to characterize the association between glycemic control and sleepiness in people with OSA and type 2 diabetes.

METHODS

Adults with non-insulin requiring type 2 diabetes and undiagnosed moderate to severe OSA were recruited from the community. Demographic data, Epworth Sleepiness Scale (ESS), hemoglobin A1c (HbA1c), as well a type III home sleep test were obtained. The association between self-reported sleepiness and glycemic control was examined using quantile regression.

RESULTS

The study cohort included 311 participants with 56% of the sample being men. Stratified analyses by sex demonstrated that self-reported sleepiness was associated with a higher HbA1c level, but this association was present only in men with a body mass index (BMI) < 35 kg/m². Mean HbA1c levels were higher by 0.57% (95% confidence interval: 0.11, 1.02) in men with an ESS ≥ 11 compared to men with an ESS < 11. No such association was observed in men with a BMI ≥ 35 kg/m² or in women of any BMI category.

CONCLUSIONS

The association between self-reported sleepiness and glycemic control in people with type 2 diabetes and moderate to severe OSA varies a function of BMI and sex. The noted differences in association should be considered when assessing possible treatment effects of therapy for OSA on metabolic outcomes.

Intermittent Hypoxia Up-Regulates CCL2, RETN, and TNFα mRNAs in Adipocytes via Down-regulation of miR-452

Sleep apnea syndrome (SAS), characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]), is a risk factor for insulin resistance. Recently, IH is considered to independently cause adipose tissue inflammation/dysfunction, leading to worsening insulin resistance; however, the detailed mechanism remains unknown. We exposed mouse 3T3-L1 and human SW872 adipocytes to experimental IH or normoxia for 24 h, and analyzed mRNA expression of several adipokines. We found that the mRNA levels of RETN, TNFα, and CCL2 in SW872 and 3T3-L1 adipocytes were significantly increased by IH, whereas the promoter activities of these genes were not increased. A target mRNA search of microRNA (miR)s revealed that all human mRNAs have a potential target sequence for miR-452. The miR-452 level of IH-treated cells was significantly decreased compared to normoxia-treated cells. MiR-452 mimic and non-specific control RNA (miR-452 mimic NC) were introduced into SW872 cells, and the IH-induced up-regulation of the genes was abolished by introduction of the miR-452 mimic but not by the miR-452 mimic NC. These results indicate that IH stress down-regulates the miR-452 in adipocytes, resulting in increased levels of RETN, TNFα, and CCL2 mRNAs, leading to insulin resistance in SAS patients.

The association of coffee consumption and oxygen desaturation index during sleep among Japanese male workers

BACKGROUND AND OBJECTIVE

Coffee is a major caffeine-containing food source that can be used for treatment of apnea in prematurity. However, few studies have examined the association between coffee consumption and sleep-disordered breathing (SDB). We investigated whether coffee consumption is associated with the oxygen desaturation index (ODI) as a marker of SDB among middle-aged Japanese male workers.

METHODS

The subjects were 1126 male local government workers aged 22-59 who participated in SDB screening in 2011-2012. Daily coffee consumption was assessed by a self-administered questionnaire. We measured 3% oxygen desaturation (3%ODI) during a night's sleep using a pulse oximeter. A general linear model was used to calculate the multivariate-adjusted means of 3%ODI per quartile of coffee consumption. We further analyzed the data after stratifying by overweight and current smoking status.

RESULTS

A inverse association between coffee consumption and 3%ODI was found. The multivariate-adjusted mean of 3%ODI for the lowest and highest coffee consumption groups were 11.9 times/h and 10.6 times/h (p for trend = 0.06), respectively; 14.6 and 11.5 times/h (p for trend = 0.01) in overweight participants; and 12.7 and 11.0 times/h (p for trend = 0.06) in non-smokers. No associations were found in non-overweight and smoking workers.

CONCLUSIONS

Our results suggest that higher coffee consumption was associated with lower 3% ODI as a marker of SDB in overweight and non-smoking workers.

The effectiveness of dapagliflozin for sleep-disordered breathing among Japanese patients with obesity and type 2 diabetes mellitus

Weight reduction is important in patients with sleep-disordered breathing (SDB). In Japanese patients, slight weight reduction is effective for improving the severity of SDB. However, the effect of weight reduction after administration of sodium glucose co-transporter 2 (SGLT2) inhibitor for SDB remains unclear. The aim of this study was to evaluate the improvement of SDB from baseline after administration of dapagliflozin (5 mg) once daily for 24 weeks among Japanese patients with obesity and type 2 diabetes mellitus. Thirty Japanese patients with type 2 diabetes mellitus and SDB were enrolled in a 24-week, prospective, open-label, single-arm, multicentre trial. SDB was defined as at least five 3% oxygen desaturation index (ODI) events per hour, and moderate to severe SDB was defined as at least 15 ODI events per hour. The primary endpoint was the change in 3% ODI between before dapagliflozin administration and at 24 weeks. The prevalence of moderate to severe SDB was 20% in the present study. After administration of dapagliflozin, fasting glucose, HbA1c, aspartate aminotransferase, total cholesterol, low-density lipoprotein cholesterol, and estimated globular filtration rate decreased significantly. The improvement of 3% ODI was observed in patients with moderate to severe SDB but not mild SDB (from 25.0 ± 3.8 at baseline to 18.5 ± 6.1 at 24 weeks, p = 0.017). In conclusion, dapagliflozin might improve moderate to severe SDB but not mild SDB in Japanese patients with obesity and type 2 diabetes mellitus.

Sleep apnea and type 2 diabetes

The aim of the present review was to clarify the association between obstructive sleep apnea (OSA) and type 2 diabetes, and discuss the therapeutic role of continuous positive airway pressure (CPAP) in type 2 diabetes. OSA patients are more likely than non-OSA populations to develop type 2 diabetes, while more than half of type 2 diabetes patients suffer from OSA. Similar to Western countries, in the East Asian population, the association between these two disorders has also been reported. CPAP is the primary treatment for OSA, but the effect of CPAP on comorbid diabetes has not been established. CPAP improved glucose metabolism determined by the oral glucose tolerance test in OSA patients, and several studies have shown that CPAP improves insulin resistance, particularly in obese populations undergoing long-term CPAP. Diabetes is associated with other sleep-related manifestations as well, such as snoring and excessive daytime sleepiness. Snoring is associated with the development of diabetes, and excessive daytime sleepiness appears to modify insulin resistance. Well-designed studies are required to clarify the therapeutic effect of CPAP on diabetes. As both diabetes and OSA lead to cardiovascular disease, clinicians and healthcare professionals should be aware of the association between diabetes and OSA, and should take CPAP and health-related behaviors into consideration when treating patients with diabetes and/or OSA.

The Epidemiology of Sleep and Diabetes

PURPOSE OF REVIEW

To provide an overview of the mechanistic and epidemiologic evidence linking sleep-related exposures, such as short sleep duration, obstructive sleep apnea, shift work, and insomnia, with type 2 diabetes risk in adults.

RECENT FINDINGS

Both poor sleep habits and sleep disorders are highly prevalent among adults with type 2 diabetes. In observational studies, short sleep duration, obstructive sleep apnea, shift work, and insomnia are all associated with higher risk of incident type 2 diabetes and may predict worse outcomes in those with existing diabetes. However, interventional studies addressing sleep abnormalities in populations with or at high risk for type 2 diabetes are scarce. Although common sleep abnormalities are associated with risk of incident type 2 diabetes and worse prognosis in those with established diabetes, there are few randomized trials evaluating the impact of sleep-focused interventions on diabetes, making it difficult to determine whether the relationship is causal.

Independent relationships between cardinal features of obstructive sleep apnea and glycometabolism: a cross-sectional study

BACKGROUND

Obstructive sleep apnea (OSA) is associated with abnormal glycometabolism; however, the cardinal features of OSA, such as sleep fragmentation (SF) and intermittent hypoxia (IH), have yet to show clear, independent associations with glycometabolism.

METHODS

We enrolled 1834 participants with suspected OSA from July 2008 to July 2013 to participate in this study. Polysomnographic variables, biochemical indicators, and physical measurements were collected for each participant. Multiple linear regression analyses were used to evaluate independent associations between cardinal features of OSA and glycometabolism. Logistic regressions were used to determine the odds ratios (ORs) for abnormal glucose metabolism across microarousal index (MAI) and oxygen desaturation index (ODI) quartiles. The effect of the interaction between MAI and ODI on glycometabolism was also evaluated.

RESULTS

The MAI was independently associated with fasting insulin levels (β = 0.024, p = 0.001) and the homeostasis model assessment of insulin resistance (HOMA-IR; β = 0.006, p = 0.002) after multiple adjustments of confounding factors. In addition, the ORs for hyperinsulinemia across higher MAI quartiles were 1.081, 1.349, and 1.656, compared with the lowest quartile (p = 0.015 for a linear trend). Similarly, the ODI was independently associated with fasting glucose levels (β = 0.003, p < 0.001), fasting insulin levels (β = 0.037, p < 0.001), and the HOMA-IR (β = 0.010, p < 0.001) after adjusting for multiple factors. The ORs for hyperglycemia across higher ODI quartiles were 1.362, 1.231, and 2.184, compared with the lowest quartile (p < 0.05 for a linear trend). In addition, the ORs for hyperinsulinemia and abnormal HOMA-IR across ODI quartiles had the same trends. There was no interaction between MAI and ODI with respect to glycometabolism.

CONCLUSION

SF was independently associated with hyperinsulinemia, and IH was independently associated with hyperglycemia, hyperinsulinemia, and an abnormal HOMA-IR. We found no interaction between SF and IH with respect to OSA-related abnormal glycometabolism.

Excessive Daytime Sleepiness Is Associated With Depression Scores, But Not With Sleep-Disordered Breathing in Patients With Cardiovascular Diseases

BACKGROUND

Excessive daytime sleepiness (EDS) is a significant public health concern, with sleep-disordered breathing (SDB) being a common cause. However, their precise relationship in patients with cardiovascular disease (CVD) is unclear. Furthermore, whether comorbid psychological disorders could contribute to EDS remains unknown. We aimed to assess the prevalence of EDS and its related factors, including SDB and depression, in patients with CVD.Methods and Results:We analyzed data from 1,571 patients admitted for various CVDs in a single university hospital (median age, 67 [56-76] years; 29.6% women). We assessed EDS using the Japanese version of the Epworth Sleepiness Scale (ESS; median 6.0 [4.0-9.0]). The presence of EDS (ESS >10, n=297 [18.9%]) did not differ between patients with and without SDB, which was screened with nocturnal pulse oximetry. In contrast, the patients with EDS had higher depression scores (Hospital Anxiety and Depression Scale subscore for depression [HADS-D] and Patient Healthcare Questionnaire [PHQ]-9). The depression scores, measured by HADS-D (odds ratio [OR] 1.14; 95% confidence interval [CI], 1.07-1.22) and PHQ-9 (OR, 1.14; 95% CI, 1.07-1.20) were independent determinants of EDS. These relationships among EDS, SDB, and depression were consistent among the subgroups with cardiovascular comorbidities.

CONCLUSIONS

The presence of EDS is associated with depressive symptoms, but not with SDB, in patients with CVD, suggesting that these patients should be thoroughly assessed for psychological disturbances.

Models of intermittent hypoxia and obstructive sleep apnea: molecular pathways and their contribution to cancer

Obstructive sleep apnea (OSA) is common and linked to a variety of poor health outcomes. A key modulator of this disease is nocturnal intermittent hypoxia. There is striking epidemiological evidence that patients with OSA have higher rates of cancer and cancer mortality. Small-animal models demonstrate an important role for systemic intermittent hypoxia in tumor growth and metastasis, yet the underlying mechanisms are poorly understood. Emerging data indicate that intermittent hypoxia activates the hypoxic response and inflammatory pathways in a manner distinct from chronic hypoxia. However, there is significant heterogeneity in published methods for modeling hypoxic conditions, which are often lacking in physiological relevance. This is particularly important for studying key transcriptional mediators of the hypoxic and inflammatory responses such as hypoxia-inducible factor (HIF) and NF-κB. The relationship between HIF, the molecular clock, and circadian rhythm may also contribute to cancer risk in OSA. Building accurate in vitro models of intermittent hypoxia reflective of OSA is challenging but necessary to better elucidate underlying molecular pathways.

Characteristics of Obstructive Sleep Apnea Across the Spectrum of Glucose Tolerance in Obese Adolescents

BACKGROUND

It is not known if dysglycemia and sleep-disordered breathing are linked in adolescents, as in adults.

OBJECTIVE

To perform a pilot study evaluating measures of sleep-disordered breathing across the spectrum of glucose tolerance in obese adolescents. We hypothesized that dysglycemia would be associated with sleep-disordered breathing.

PARTICIPANTS/METHODS

This was a prospective, cross-sectional clinical pilot study that included 57 adolescents [body mass index (BMI) 38.9 ± 8.4 kg/m²] aged 12-18 years (14.5 ± 1.6) with normal glucose tolerance (NGT), or dysglycemia [impaired glucose tolerance (IGT) or type 2 diabetes (T2D)].

MEASURES

Anthropometrics, overnight polysomnogram, and oral glucose tolerance tests were performed. Participant characteristics and outcome measures were compared by glucose tolerance status. Correlational analyses were conducted to assess the associations between variables of interest.

RESULTS

Participants with dysglycemia (n = 21) were not different from those with NGT (n = 36) for BMI, waist circumference, body fat, or sleep characteristics. Nocturnal oxygen desaturation was associated with higher BMI (r = -0.334, p = 0.012). The apnea-hypopnea index (AHI) was not associated with physical and metabolic parameters. Although participants with dysglycemia tended to have higher AHIs (median 3.2, 2.2, and 1.6 events/h for T2D, IGT, and NGT, respectively), there was not a linear relationship between measures of glycemia and AHI.

CONCLUSION

Further study with a larger proportion of youth with prediabetes and T2D is necessary to determine whether evaluation for sleep-disordered breathing is uniformly warranted.

Associations between Sleep-Disordered Breathing and Metabolic Risk Factors beyond Obesity

OBJECTIVE

Individuals with multiple metabolic risk factors often experience concomitant sleep-disordered breathing (SDB). We aimed to determine the associations of SDB with individual components of metabolic syndrome independent of obesity.

METHODS

A cross-sectional study was conducted in 1137 employees aged 30-64 years. Apnea-hypopnea index (AHI) was assessed using a portable monitor for obstructive sleep apnea by admission. Of these, 451 participants took an oral glucose tolerance test to assess homeostatic model assessment of insulin resistance (HOMA-IR) and Matsuda insulin sensitivity index (ISI).

RESULTS

The odds ratio (OR) of the highest category of the AHI (≥15 episodes per hour) compared to the lowest one (<5 episodes per hour) was significantly elevated for hypertension, for hypertriglyceridemia, and for low HDL-cholesterolemia when adjusted for age, sex, and alcohol and smoking status (p < 0.05). After further adjustment for body mass index (BMI) or waist circumference, the associations for hypertension still remained statistically significant (p < 0.05) while those for hypertriglyceridemia and low HDL-cholesterolemia were no longer significant. The association between higher insulin resistance as assessed by HOMA-IR and Matsuda ISI and higher categories of the AHI was also lost after adjustment for BMI.

CONCLUSION

Obesity was a strong confounding factor in the association between SDB and most metabolic risk factors including insulin resistance, except for hypertension. Further longitudinal study is needed to examine the temporal or causal relationships between SDB and metabolic risk factors. This trial is registered with UMIN-CTR UMIN000028067.

The role of sleep duration and sleep disordered breathing in gestational diabetes mellitus

Many women experience sleep problems during pregnancy. This includes difficulty initiating and maintaining sleep due to physiologic changes that occur as pregnancy progresses, as well as increased symptoms of sleep-disordered breathing (SDB). Growing evidence indicates that sleep deficiency alters glucose metabolism and increases risk of diabetes. Poor sleep may exacerbate the progressive increase in insulin resistance that normally occurs during pregnancy, thus contributing to the development of maternal hyperglycemia. Here, we critically review evidence that exposure to short sleep duration or SDB during pregnancy is associated with gestational diabetes mellitus (GDM). Several studies have found that the frequency of GDM is higher in women exposed to short sleep compared with longer sleep durations. Despite mixed evidence regarding whether symptoms of SDB (e.g., frequent snoring) are associated with GDM after adjusting for BMI or obesity, it has been shown that clinically-diagnosed SDB is prospectively associated with GDM. There are multiple mechanisms that may link sleep deprivation and SDB with insulin resistance, including increased levels of oxidative stress, inflammation, sympathetic activity, and cortisol. Despite emerging evidence that sleep deficiency and SDB are associated with increased risk of GDM, it has yet to be demonstrated that improving sleep in pregnant women (e.g., by extending sleep duration or treating SDB) protects against the development of hyperglycemia. If a causal relationship can be established, behavioral therapies for improving sleep can potentially be used to reduce the risk and burden of GDM.

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Many pregnant women experience reduced sleep or sleep-disordered breathing.

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Growing evidence suggests that short sleep is associated with gestational diabetes.

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Sleep-disordered breathing may increase risk of gestational diabetes.

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Poor sleep during pregnancy may promote mechanisms linked with insulin resistance.

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Future studies should test if improving sleep reduces risk of gestational diabetes.

Up-regulation of selenoprotein P and HIP/PAP mRNAs in hepatocytes by intermittent hypoxia via down-regulation of miR-203

Sleep apnea syndrome is characterized by recurrent episodes of oxygen desaturation and reoxygenation (intermittent hypoxia [IH]) and is a risk factor for insulin resistance/type 2 diabetes. However, the mechanisms linking IH stress and insulin resistance remain elusive. We exposed human hepatocytes (JHH5, JHH7, and HepG2) to experimental IH or normoxia for 24 h, measured mRNA levels by real-time reverse transcription polymerase chain reaction (RT-PCR), and found that IH significantly increased the mRNA levels of selenoprotein P (SELENOP) — a hepatokine — and hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP) — one of REG (Regenerating gene) family. We next investigated promoter activities of both genes and discovered that they were not increased by IH. On the other hand, a target mRNA search of micro RNA (miRNA) revealed that both mRNAs have a potential target sequence for miR-203. The miR-203 level of IH-treated cells was significantly lower than that of normoxia-treated cells. Thus, we introduced miR-203 inhibitor and a non-specific control RNA (miR-203 inhibitor NC) into HepG2 cells and measured the mRNA levels of SELENOP and HIP/PAP. The IH-induced expression of SELENOP and HIP/PAP was abolished by the introduction of miR-203 inhibitor but not by miR-203 inhibitor NC. These results demonstrate that IH stress up-regulates the levels of SELENOP in human hepatocytes to accelerate insulin resistance and up-regulates the levels of HIP/PAP mRNAs to proliferate such hepatocytes, via the miR-203 mediated mechanism.

HbA1c levels are associated with severity of hypoxemia and not with apnea hypopnea index in patients with type 2 diabetes: Results from a cross-sectional study

BACKGROUND

The aim of the present study was to evaluate the effect of untreated sleep apnea syndrome (SAS) on glycemic control, evaluated by HbA1c, in patients with type 2 diabetes (T2D).

METHODS

The study sample consisted of 100 consecutive adult (≥18 years) patients with T2D without a prior diagnosis of sleep apnea recruited from an outpatient diabetes clinic. All patients underwent an in-hospital cardiorespiratory study using a three-channel portable sleep diagnostic tool; 64 were found to have sleep apnea, 36 were not. Information on medical history, body weight, height, sleep apnea symptoms, Epworth Sleepiness Scale scores, and HbA1c and fasting plasma glucose levels were recorded.

RESULTS

After adjusting for factors known to affect HbA1c (gender, age, diabetes duration, diabetes treatment, body mass index [BMI], and waist circumference), HbA1c was higher in patients with than without SAS (8.4 % vs 7.6 %, respectively; P = 0.04). A positive correlation was found between the presence of sleep apnea and HbA1c (r = 0.24; P = 0.02). After adjusting for confounding factors (including BMI), only mean and lowest O₂ saturation during sleep were significantly associated with HbA1c (β = -0.23 [P = 0.03] and β = -0.24 [P = 0.007], respectively). After further adjusting for waist circumference, only lowest O₂ saturation during recording remained independently associated with HbA1c (β = -0.21; P = 0.05).

CONCLUSIONS

The presence of sleep apnea is associated with poorer glycemic control in patients with T2D. In patients with sleep apnea and T2D, greater levels of oxygen desaturation are associated with poorer glycemic control.

Scalloped tongue is associated with nocturnal intermittent hypoxia among community-dwelling Japanese: the Toon Health Study

Scalloped tongue is considered as a possible clinical finding of obstructive sleep apnoea (OSA). There are few evidence of the association between scalloped tongue and OSA. To examine the association between scalloped tongue and nocturnal intermittent hypoxia (NIH), a surrogate marker of OSA, among a general Japanese population. Study participants were 398 men and 732 women aged 30-79 years who participated in the Toon Health Study from 2011 to 2014. Scalloped tongue was classified into three categories: none, mild and moderate-to-severe. Moderate-to-severe NIH was defined as the 3% oxygen desaturation index of ≥15 events/h during sleep for one night with pulse oximetry. The multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for moderate-to-severe NIH were calculated according to scalloped tongue categories using a logistic regression model. There were 69 (6·1%) moderate-to-severe NIH cases in this population. The multivariable-adjusted ORs (95% CIs) of moderate-to-severe NIH were 1·59 (0·85-2·95) for mild and 2·39 (1·10-5·17) for the moderate-to-severe scalloped tongue group compared with the group without scalloped tongues. When stratified by overweight status (BMI <25 or ≥25 kg m^-2 ), the respective ORs (95% CIs) were 2·83 (1·06-7·55) and 4·74 (1·28-17·49) among overweight individuals, and 0·94 (0·40-2·70) and 1·52 (0·57-4·05) among non-overweight individuals. Scalloped tongue was associated with higher prevalence of moderate-to-severe NIH among the general Japanese population and this association was more evident in overweight individuals.

Assessing Whether the Association Between Sleep Apnea and Diabetes is Bidirectional

OBJECTIVES

To determine whether there is a bidirectional association between sleep apnea and diabetes mellitus.

METHODS

We conducted longitudinal analyses of a population-based cohort over 12 years using Taiwan's national universal health insurance database. In analysis I, we included 102 355 individuals without type 2 diabetes mellitus at baseline and estimated the hazard ratio of incident diagnosis of type 2 diabetes mellitus for patients with and those without sleep apnea. In analysis II, we included 258 053 participants without sleep apnea at baseline and calculated the hazard ratio of developing sleep apnea for patients with and those without type 2 diabetes.

RESULTS

In analysis I, the incidence rates of type 2 diabetes were 17.7 and 11.1 per 1000 person-years for patients with and those without sleep apnea, respectively. Patients with sleep apnea had an increased risk for diabetes (adjusted hazard ratio [aHR] = 1.33; 95% confidence interval [CI], 1.22 to 1.46). In analysis II, the risk for sleep apnea with diabetes was not statistically significant (aHR = 1.06; 95% CI, 0.98 to 1.16). These associations in both analyses did not substantively change after accounting for various latent periods.

CONCLUSIONS

Baseline sleep apnea is associated with incident type 2 diabetes; however, the presence of type 2 diabetes cannot predict the development of sleep apnea.

Obstructive sleep apnea and incident type 2 diabetes

OBJECTIVES

To determine whether severity of obstructive sleep apnea is associated with incident diabetes in middle-aged and older adults.

METHODS

A prospective analysis of 1453 non-diabetic participants of both the Atherosclerosis Risk in Communities Study and the Sleep Heart Health Study (mean age 63 years, 46% male) had in-home polysomnography (1996-1998) and was followed up for incident diabetes. Using the apnea-hypopnea index derived from home polysomnography, study participants were categorized as follows: <5.0 (normal), 5.0-14.9 (mild), 15.0-29.9 (moderate), and ≥30.0 events/h (severe). Incident diabetes was ascertained during annual follow-up telephone calls through 2013.

RESULTS

During a median follow-up of 13 years, there were 285 incident diabetes cases among the 1453 participants. Participants with severe obstructive sleep apnea were at greater risk of incident diabetes compared to persons classified as normal after adjustment for confounders including body mass index and waist circumference (1.71 [1.08, 2.71]). The association between severe obstructive sleep apnea and incident diabetes was similar when analyses were restricted to obese individuals.

CONCLUSIONS

Severe obstructive sleep apnea was associated with greater risk of incident diabetes, independent of adiposity in a community-based sample. Healthcare professionals should be cognizant of the high prevalence of OSA in the general population and the potential link to incident diabetes.

Role of sleep quality in the metabolic syndrome

Emerging evidence has assigned an important role to sleep as a modulator of metabolic homeostasis. The impact of variations in sleep duration, sleep-disordered breathing, and chronotype to cardiometabolic function encompasses a wide array of perturbations spanning from obesity, insulin resistance, type 2 diabetes, the metabolic syndrome, and cardiovascular disease risk and mortality in both adults and children. Here, we critically and extensively review the published literature on such important issues and provide a comprehensive overview of the most salient pathophysiologic pathways underlying the links between sleep, sleep disorders, and cardiometabolic functioning.

Blood biomarkers of endocrine, immune, inflammatory, and metabolic systems in obstructive sleep apnea

OBJECTIVE/BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder, affecting over 100 million adults. Untreated OSA leads to serious health consequences and perturbations in endocrine, immune, inflammatory, and metabolic systems. Study objectives are to evaluate the association between OSA and biomarkers, and to test the hypothesis that a combination of markers may be useful in screening for OSA.

PATIENTS/METHODS

A multicenter trial was conducted enrolling symptomatic male patients with suspected OSA. All subjects underwent in-laboratory overnight polysomnography. A non-symptomatic control group was also obtained. Eleven biomarkers were tested: HbA1c, CRP, EPO, IL-6, uric acid, cortisol, hGH, prolactin, testosterone, DHEA (Beckman Coulter UniCel DxC 600i Synchron® Access® Clinical Systems), IGF-1.

RESULTS

73 male subjects were enrolled; 26 had moderate/severe OSA. ROC curve analysis showed HbA1c, CRP, EPO, IL-6, and Uric Acid (AUCs: 0.76, 0.73, 0.65, 0.65, 0.61) were superior to the Epworth Sleepiness Scale (AUC: 0.52). Concurrent elevation of HbA1c and CRP provide even greater predictive power. A combination of elevated HbA1c, CRP, and EPO provided 0.08 increase in AUC (0.84 [0.75 - 0.94]) over individual markers (p<0.05), with high sensitivity (85%), and specificity (79%) for moderate/severe OSA.

CONCLUSIONS

OSA induces characteristic endocrine, immune, inflammatory, and metabolic disturbances that can be detected with blood biomarkers. These biomarkers are superior to standard screening questionnaires. Various clusters of these biomarkers have an even greater association with OSA and thus may represent physiologic signatures of the disorder that may have value in initial screening for OSA as well as for follow-up of therapy response.