Evangelia Nena

Markers of glycemic control and insulin resistance in non-diabetic patients with Obstructive Sleep Apnea Hypopnea Syndrome: Does adherence to CPAP treatment improve glycemic control?

BACKGROUND AND AIM Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is associated with glucose dysmetabolism and insulin resistance, therefore the amelioration of breathing disturbances during sleep can allegedly modify the levels of markers of glucose regulation and insulin resistance, such as glycated hemoglobin, fasting glucose, insulin and HOMA(IR). The aim of this study was to explore the association between these parameters and sleep characteristics in non-diabetic OSAHS patients, as well as the effect of 6 months CPAP therapy on these markers, according to adherence to CPAP treatment. METHODS Euglycemic patients (n=56; mean age+/-SD: 46.07+/-10.67 years) with newly diagnosed OSAHS were included. Glycated hemoglobin, fasting glucose, insulin levels and HOMA(IR) were estimated at baseline and 6 months after CPAP application. According to CPAP adherence, patients were classified as follows: group 1 (mean CPAP use 4 h/night), group 2 (mean CPAP use < 4 h/night) and group 3 (refused CPAP treatment), and comparisons of levels of the examined parameters were performed. RESULTS At baseline, average SpO(2) during sleep was negatively correlated with insulin levels and HOMA(IR) while minimum SpO(2) during sleep was also negatively correlated with insulin levels. After 6 months, only group 1 patients demonstrated a significant decrease in glycated hemoglobin (p=0.004) accompanied by a decrease in hs-CRP levels (p=0.002). No other statistically significant change was observed. CONCLUSIONS Nighttime hypoxia can affect fasting insulin levels in non-diabetic OSAHS patients. Good adherence to long-term CPAP treatment can significantly reduce HbA(1C) levels, but has no effect on markers of insulin resistance.

HbA1c is associated with severity of obstructive sleep apnea hypopnea syndrome in nondiabetic men

The aim of this study was to examine the potential correlation of sleep characteristics with glucose metabolism in nondiabetic men with obstructive sleep apnea syndrome (OSAS). Included were 31 male patients (mean age 46.7 ±11 years), recently diagnosed with OSAS by full polysomnography. There was a significant correlation of fasting glucose and glycosylated hemoglobin (HbA1c) levels with arousal index (P = 0.047 and P =0.014, respectively). Moreover, HbA1c levels were correlated with apnea hypopnea index (P =0.009), a widely accepted marker of the severity of OSAS, and with percentage of sleep time with saturation of hemoglobin with oxygen as measured by pulse oximetry (SpO2) < 90% (t < 90%) ( P =0.010). Finally, glucose and HbA1c levels showed a significant negative correlation with average SpO2 (P =0.013 and P = 0.012, respectively) and, additionally, glucose levels with minimum SpO 2 (P =0.027) during sleep. In conclusion, severity of OSAS among nondiabetic men is associated with increased HbA1c levels and increased fasting glucose. Thus, severity of OSAS may be an additional marker of cardiovascular risk, as well as of future diabetes, in these subjects. However, further work is needed to confirm the clinical significance of these observations.

Lung Cancer and Interstitial Lung Diseases: A Systematic Review

Interstitial lung diseases (ILDs) represent a heterogeneous group of more than two hundred diseases of either known or unknown etiology with different pathogenesis and prognosis. Lung cancer, which is the major cause of cancer death in the developed countries, is mainly attributed to cigarette smoking and exposure to inhaled carcinogens. Different studies suggest a link between ILDs and lung cancer, through different pathogenetic mechanisms, such as inflammation, coagulation, dysregulated apoptosis, focal hypoxia, activation, and accumulation of myofibroblasts as well as extracellular matrix accumulation. This paper reviews current evidence on the association between lung cancer and interstitial lung diseases such as idiopathic pulmonary fibrosis, sarcoidosis, systemic sclerosis, dermatomyositis/polymyositis, rheumatoid arthritis, systemic lupus erythematosus, and pneumoconiosis.

Inflammatory Markers in Middle-Aged Obese Subjects: Does Obstructive Sleep Apnea Syndrome Play a Role?

Background. Obstructive Sleep Apnea Syndrome (OSAS) is associated with inflammation, but obesity may be a confounding factor. Thus, the aim of this study was to explore differences in serum levels of inflammation markers between obese individuals with or without OSAS. Methods. Healthy individuals (n = 61) from an outpatient obesity clinic were examined by polysomnography and blood analysis, for measurement of TNF-α, IL-6, CRP, and fibrinogen levels. According to Apnea-Hypopnea Index (AHI), participants were divided into two BMI-matched groups: controls (AHI < 15/h, n = 23) and OSAS patients (AHI ≥ 15/h, n = 38). Results. OSAS patients had significantly higher TNF-α levels (P < .001) while no other difference in the examined inflammation markers was recorded between groups. Overall, TNF-α levels were correlated with neck circumference (P < .001), AHI (P = .002), and Oxygen Desaturation Index (P = .002). Conclusions. Obese OSAS patients have elevated TNF-α levels compared to BMI-matched controls, suggesting a role of OSAS in promoting inflammation, possibly mediated by TNF-a.

Mean platelet volume and platelet distribution width in patients with chronic obstructive pulmonary disease: the role of comorbidities.

We evaluated mean platelet volume (MPV; an indicator of vascular risk) and platelet distribution width in patients with stable chronic obstructive pulmonary disease (COPD; n = 85). We also included a control group of 34 smokers without airflow limitation. Mean platelet volume was significantly higher in patients with COPD (10.69 ± 1.0 vs 9.96 ± 1.10 fL, P < .001) than in the smoker controls. White blood cell (WBC) count was also significantly higher in patients with COPD than in the smoker controls (10 642 ± 1247 vs 7136 ± 1887/μL, P < .001). There was a correlation between MPV and WBC in patients with COPD, especially in those at stage III (r = .530, P = .004) and IV (r = .389, P = .023). Mean platelet volume did not correlate with any indices of COPD severity. In patients with COPD, MPV and WBC levels are higher than those of smokers with normal pulmonary function and are significantly correlated. Whether these effects relate to vascular risk in patients with COPD remain to be established.

Sleepiness as a marker of glucose deregulation in obstructive sleep apnea

BackgroundExcessive daytime sleepiness (EDS) is a major but not universally present feature of obstructive sleep apnea syndrome (OSAS). The latter has been associated with glucose dysmetabolism and insulin resistance. The aim of this study was to examine the role of EDS by investigating potential differences between somnolent and non-somnolent OSAS patients in glucose metabolism, insulin resistance, and levels of cardiovascular risk factors.MethodsIncluded were 25 newly diagnosed otherwise healthy OSAS patients, reporting EDS (ESS ≥ 11) and 25 age- and BMI-matched, non-somnolent (ESS ≤ 10) OSAS patients, who served as controls. Fasting glucose and insulin levels, as well as homeostatic model assessment of insulin resistance (HOMAIR) index, levels of hs-CRP, and lipidemic profile were measured.ResultsThe two groups did not differ in anthropometric or sleep characteristics. A significant correlation of ESS with glucose (p = 0.004), insulin (p = 0.011), and HOMAIR (p = 0.031) was observed. Somnolent patients had higher levels of glucose (p = 0.045), insulin (p = 0.012), and HOMAIR (p = 0.027). No difference was detected in other markers between the two groups.ConclusionsDaytime sleepiness in OSAS patients is associated with hyperglycemia and hyperinsulinemia. These results suggest its potential use as a surrogate marker of insulin resistance in such patients.

Continuous Positive Airway Pressure Treatment in Patients with Sleep Apnoea: Does it Really Improve Glucose Metabolism?

Obstructive Sleep Apnoea Syndrome (OSAS) is a common disorder, characterised by repetitive episodes of partial or complete obstruction of the upper airway during sleep and associated with increasing respiratory efforts. These perturbations lead, in turn, to oxyhaemoglobin desaturation, sleep fragmentation, and daytime symptoms, mainly excessive sleepiness. Accumulating evidence suggests that intermittent hypoxia and oxyhaemoglobin desaturation may result, independently of obesity, in impaired glucose metabolism, as well as insulin resistance even in non-diabetic patients with OSAS. Additionally, OSAS has been proposed as an independent risk factor for type 2 diabetes mellitus. Continuous Positive Airway Pressure (CPAP) is the treatment of choice for OSAS, since it eliminates upper airway collapse during sleep and also improves sleep fragmentation, daytime symptoms and quality of life. Moreover, it has been proposed that the amelioration of breathing disturbances during sleep can improve several markers of glucose metabolism and insulin resistance, such as glycated haemoglobin, fasting glucose, insulin, and insulin resistance. Indeed, some studies have reported improvements in these parameters especially in compliant patients. However, other works failed to confirm this beneficial effect. The present article reviews the issue whether CPAP treatment exerts a beneficial effect on glucose metabolism and insulin resistance.

Work productivity in obstructive sleep apnea patients.

Objectives: Purpose of the study was to assess work productivity in otherwise healthy obstructive sleep apnea (OSA) patients and to explore correlations between work productivity and different characteristics of OSA patients. Methods: Work productivity was assessed by the Endicott Work Productivity Scale (EWPS) to 115 polysomnographically confirmed OSA patients of working age, without comorbidities. Daytime sleepiness was measured by the Epworth Sleepiness Scale. Results: A significant correlation was revealed between EWPS and Epworth Sleepiness Scale scores (r2 = 0.127, P < 0.001). Mean EWPS score was significantly higher in somnolent versus nonsomnolent OSA patients (31.2 ± 16.2 vs 20.8 ± 11, respectively; P < 0.001). No other sleep or anthropometric characteristic correlated with EWPS. Conclusions: This study demonstrates the negative effect of daytime sleepiness on work productivity of otherwise healthy OSA patients, highlighting the need of screening for OSA and sleepiness among working individuals.

Sleep-Disordered Breathing and Quality of Life of Railway Drivers in Greece

BACKGROUND Sleep-disordered breathing (SDB) and especially obstructive sleep apnea (OSA) are associated with daytime sleepiness and an increased risk for motor vehicle crashes. Previous studies have assessed the prevalence of OSA among professional drivers, but no study so far has focused on railway drivers. The aim of this study was to assess the prevalence of SDB among Greek railway drivers, and correlate it with daytime sleepiness, quality of life, and symptoms. METHODS The following three different questionnaires were anonymously answered by 226 train drivers: a general questionnaire on their demographics and sleep habits; the Greek version of the Epworth sleepiness scale (ESS); and the Medical Outcomes Study 36-item short form (SF-36). Of the 226 drivers, 50 underwent a sleep study, a physical examination, and an assessment of their respiratory function. RESULTS Participants were all men, had a mean (+/-SD) age of 46.9+/-3.9 years, were overweight (mean body mass index [BMI], 28.7+/-3.7 kg/m2), and were smokers (59.7%). Snoring was reported by 69.9% of them, and apneas by 11.5%. The mean ESS score was 5.4+/-3.2. SF-36 scores were similar to those of the Greek population. The mean apnea-hypopnea index (AHI) was 11+/-14 events per hour, and the mean pulse oximetric saturation was 93.2+/-2.5%. According to AHI severity, they were divided into the following three groups: group 1, normal breathing function in sleep (n=19; AHI, <5 events per hour); group 2, mild OSA (n=20; AHI, 5.1 to 15 events per hour); group 3, moderate/severe OSA (n=11; AHI, >15 events per hour). The three groups differed in terms of BMI, and neck, waist, and hip circumferences. No difference was detected, though, in ESS and SF-36 scores. CONCLUSION The majority of the Greek railway drivers are overweight and smokers. The most common reported symptom in the questionnaires is snoring, without significant daytime impairment, while sleep studies show a potentially higher prevalence of OSA. TRIAL REGISTRATION Democritus University of Thrace Identifier: 2979/5-2003. TRIAL REGISTRATION Union of the Greek Railway Drivers Identifier: 536/10-2003.

Biomarkers to Improve Diagnosis and Monitoring of Obstructive Sleep Apnea Syndrome: Current Status and Future Perspectives

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent episodes of upper airway collapse associated with oxygen desaturation and sleep disruption. It is proposed that these periodic changes lead to molecular variations that can be detected by assessing serum biomarkers. Studies have identified inflammatory, oxidative, and metabolic perturbations attributable to sleep-disordered breathing. Given that OSAS is associated with increased cardiovascular and cerebrovascular morbidity, the ideal biomarker should enable timely recognition with the possibility of intervention. There is accumulating data on the utility of serum biomarkers for the evaluation of disease severity, prognosis, and response to treatment. However, current knowledge is limited by data collection techniques, disease complexity, and potential confounding factors. The current paper reviews the literature on the use of serum biomarkers in OSAS. It is concluded that the ideal serum biomarker still needs to be discovered, while caution is needed in the interpretation of hitherto available results.