Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy.

PURPOSE: Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy. METHODS: The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights. RESULTS: The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months. CONCLUSIONS: Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS.

The DJ-1 protein as a candidate biomarker in obstructive sleep apnea syndrome.

BACKGROUND: Oxidative stress has a central role in the pathophysiology of obstructive sleep apnea syndrome (OSAS). The DJ-1 protein functions as a sensor of oxidative stress, acting both as a reactive oxygen species scavenger (ROS) and an antioxidative response regulator. The aim of our study is to determine the serum levels of DJ-1 in OSAS patients and assess possible correlations with their clinical, demographical, and biochemical characteristics. METHODS: The study included 120 subjects from the Sleep Disorder Laboratory of the University Hospital of Thessaly (100 males vs 20 females, mean age 48±10, Apnea-Hypopnea Index (AHI)>5 episodes per hour of sleep). Subjects underwent full-night polysomnography (PSG) followed by morning blood sampling. Serum DJ-1 levels were determined via ELISA kits. Statistical analysis was performed using SPSS 19. RESULTS: The median DJ-1 levels were 56.7 ng/mL (IQR, 34.9-99.3 ng/mL). Statistically significant correlations were detected between DJ-1's levels and AHI (Spearman's rho=0.189, P=0.04), Desaturation Index (DI; Spearman's rho=0.239, P=0.012), and serum low-density lipoprotein (LDL) (Spearman's rho=-0.205, P=0.042). CONCLUSIONS: DJ-1 may be a useful biomarker in OSAS due to its correlations with AHI and DI. The correlation with serum LDL warrants further investigation regarding possible implications in OSAS patients' cardiovascular comorbidities.