Sleepiness and Vitamin D Levels in Patients with Obstructive Sleep Apnea

Abstract

Study Objectives: The aim of this cross-sectional study is to explore the association between serum 25-hydroxyvitamin D [25(OH)D] levels, a marker of Vitamin D status, and excessive daytime sleepiness (EDS), expressed as increased scores of the Epworth Sleepiness Scale (ESS), in a group of prospectively enrolled patients with obstructive sleep apnea (OSA). Methods: Newly diagnosed patients with OSA, divided into two groups, those with EDS (ESS > 10) and those without EDS (ESS p p = 0.005]. In patients with EDS, serum 25(OH)D levels correlated with average oxyhemoglobin saturation during sleep (r = 0.194, p = 0.043), and negatively with ESS score (r = −0.285, p = 0.003), AHΙ (r = −0.197, p = 0.040) and arousal index (r = −0.256, p = 0.019). Binary regression analysis identified Vit D serum levels (β = −0.045, OR: 0.956, 95% CI: 0.916–0.997, p = 0.035), total sleep time (β = 0.011, OR: 1.011, 95% CI: 1.002–1.021, p = 0.016) and AHI (β = 0.022, OR: 1.022, 95% CI: 1.003–1.043, p = 0.026) as independent predictors of EDS in patients with OSA. In patients with EDS, multiple regression analysis indicated that ESS score was negatively associated with Vit D serum levels (β = −0.135, p = 0.014) and minimum oxyhemoglobin saturation during sleep (β = −0.137, p = 0.043). Conclusions: In the present study, EDS in patients with OSA is associated with low levels of Vitamin D, while sleep hypoxia may play a role in this process.

Keywords

• vitamin D
• sleepiness
• obstructive sleep apnea (OSA)
• sleep apnea
• Epworth sleepiness scale (ESS)