Vitamin D Levels in Middle-Aged Patients with Obstructive Sleep Apnoea Syndrome.

BACKGROUND: Vitamin D (Vit D) insufficiency has been implicated in the pathophysiology of numerous diseases. Obstructive sleep apnoea syndrome (OSAS), a disorder associated with increased cardiovascular and cerebrovascular morbidity, has been associated with decreased Vit D levels, but reports are inconclusive. AIM: To evaluate the association between serum 25-hydroxyvitamin D [25(OH)D], a marker of Vit D status, with anthropometric and sleep characteristics of OSAS patients and to compare those levels between OSAS patients and non-apnoeic controls. METHOD: Consecutive subjects who had undergone polysomnography and pulmonary function testing were divided into controls (apnoea-hypopnea index, AHI <5/h) and OSAS group (AHI ≥5/h). RESULTS: A total of 169 subjects (135 men) were included. OSAS patients (n=139) significantly differed from non-apnoeic controls in terms of age (53.9±12.8 vs. 44.9±12.8 years, p=0.002) and body mass index (BMI) (35.9±6.9 vs. 29.9±6.8 kg/m2, p<0.001). Serum 25(OH)D levels were lower in OSAS patients (17.8±7.8 vs. 23.9±12.4 ng/ml, p=0.019). In OSAS patients, levels of serum 25(OH)D were negatively correlated with sleep stage transitions (r=-0.205, p=0.028), AHI (r=-0.187, p=0.045), oxygen desaturation index (r=-0.234, p=0.011) and percentage of time with oxyhaemoglobin saturation <90% (r=-0.172, p=0.041). In contrast, they were positively correlated with average oxyhaemoglobin saturation during sleep (r=0.179, p=0.033), forced expiratory volume in 1 sec (r=0.207, p=0.037) and oxygen partial pressure (r=0.197, p=0.029). CONCLUSION: Vit D levels were lower in OSAS patients compared with non-apnoeic controls. Several indices of OSAS severity also correlated with Vit D levels.

Insulin Sensitivity and Insulin Resistance in Non-Diabetic Middle-Aged Patients with Obstructive Sleep Apnoea Syndrome.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) has been linked with abnormal glucose metabolism, insulin resistance (IR) and development of diabetes mellitus. METHODS: Non-diabetic patients (n=69) with OSAS, diagnosed by polysomnography, were prospectively recruited. To evaluate IR among OSAS patients, the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and Insulin sensitivity by Quantitative Insulin sensitivity Check Index (QUICKI) were used. RESULTS: HOMA-IR was positively associated with body-mass index (BMI) (ρ=0.364, p=0.002), time with oxyhaemoglobin saturation <90% (ρ=0.291, p=0.015), arousal index (ρ=0.268, p=0.027), Epworth sleepiness scale (ESS) score (ρ=0.293, p=0.019) and negatively with average oxyhaemoglobin saturation (ρ=-0.398, p=0.001) and minimum oxyhaemoglobin saturation (ρ=-0.327, p=0.006). QUICKI was positively associated with forced vital capacity (r=0.301, p=0.014), average oxyhaemoglobin saturation (r=0.443, p<0.001), minimum oxyhaemoglobin saturation (ρ=0.318, p=0.008), and negatively associated with sleep stage transitions (r=-0.266, p=0.032), oxygen desaturation index (r=-0.404, p=0.005), time with oxyhaemoglobin saturation <90% (r=-0.311, p=0.019), arousal index (r=-0.344, p=0.004) and ESS score (r=-0.299, p=0.016). After adjustment for age and BMI, HOMA-IR was associated with sleep stage transitions, time with oxyhaemoglobin saturation <90%, average oxyhaemoglobin saturation, minimum oxyhaemoglobin saturation and arousal index. QUICKI was associated with oxygen desaturation index, sleep stage transitions, ESS score, minimum oxyhaemoglobin saturation and arousal index. CONCLUSIONS: An independent association between OSAS and IR in patients without pre-existing diabetes mellitus was observed. Recurrent hypoxia and sleep fragmentation in OSAS are associated with IR in these patients.

Mean Platelet Volume as a Surrogate Marker for Platelet Activation in Patients With Idiopathic Pulmonary Fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is associated with a prothrombotic state. AIM: To study mean platelet volume (MPV) and Platelet Distribution Width (PDW) as markers of platelet activation and their potential association with lung function in patients with recently diagnosed IPF. MATERIALS AND METHODS: This study included 56 patients with IPF (age 64.9±7.4 years) and 79 controls (age 64.2 ± 5.9 years). RESULTS: An inverse relation was demonstrated between platelet count and MPV in the control group but not among patients with IPF. Platelet count was significantly lower in patients with IPF compared with controls (230 ± 60 vs 256 ± 75 × 10(3)/µL, P = .038). Conversely, MPV was higher in patients versus controls (10.3 ± 1.2 vs 9.8 ± 1.2 fl, P = .024), while there was no difference between the groups in PDW. Respiratory function was, as expected, significantly impaired in patients with IPF versus controls in terms of forced expiratory volume in first second (FEV1; 67.2 ± 23.1 vs 102.6 ± 15.9% of predicted value, P < .001), forced vital capacity (FVC; 65.3 ± 21 vs 95.2 ± 16.1% of predicted value, P < .001), FEV1/FVC (83.1 ± 15 vs 87.5 ± 6.4%, P = .041) and partial pressure of oxygen in arterial blood (PaO2; 67.1 ± 10.3 vs 81.5 ± 15.2 mm Hg, P < .001). No significant correlation was seen between MPV and FVC (r = -.1497, P = .275), MPV and lung diffusion capacity for carbon monoxide (r = .035, P = .798) and total lung capacity (r = .032, P = .820). CONCLUSIONS: Patients with IPF exhibit higher MPV values and lower platelet count. Further studies are needed to assess the clinical implications of these findings.

Is there evidence of early vascular disease in patients with obstructive sleep apnoea without known comorbidities? Preliminary findings.

We evaluated early atherosclerotic lesions in 20 non-smokers with newly diagnosed Obstructive Sleep Apnoea (OSA) and without known comorbidities by measuring common carotid artery intima media thickness (CCA-IMT), transcranial Doppler ultrasound (TCD), and ankle brachial index (ABI). These were compared with 20 healthy age- and BMI-matched controls. In OSA patients, CCA-IMT was not significantly higher vs. controls (0.74±0.17 vs. 0.66±0.12 mm, p=0.201) and it was positively correlated with neck circumference (r=0.466, p=0.039), arousal index (r=0.663, p=0.001), gamma-glutamyl transpeptidase activity (r=0.474, p=0.035) while it was negatively correlated with Forced Expiratory Volume in 1 sec (r=-0.055, p=0.012). No difference was noted between patients and controls in terms of vascular stenosis on TCD examination, while asymptomatic peripheral artery disease was found in one patient with OSA. In conclusion, OSA patients without known comorbidities exhibit a non-significant increase in CCA-IMT without further evidence of vascular disease, but additional experience in a larger patient series is needed.

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.