Obstructive sleep apnea syndrome: association of serum melatonin, increased daytime sleepiness, and intermitting night hypoxemia

Abstract

The relevance of studies related to the features of respiratory disorders during sleep is undeniable due to the steady growth of the worldwide prevalence of apnea syndrome, which leads to a decrease in quality of life, the risk of early cardiovascular diseases together with cerebrovascular, endocrine, and pulmonary disorders.The aim of this study was to determine the relationship between the morning serum melatonin, blood oxygen saturation (SрO2), and increased daytime sleepiness in patients with SOAS, as well as to assess changes in the production of endogenous melatonin after eliminating clinical manifestations of nocturnal hypoxemia, through a 3-month course of non-invasive continuous positive airway pressure (CPAP) therapy. The study enrolled 30 male patients who came to the Federal State Public Scientific Institution “Scientific Centre of Family Health and Human Reproduction Problems” because of snoring, sleep apnea, and increased daytime sleepiness.Methods. Polysomnography, questionnaire, HPLC-MS/MS analysis of serum melatonin levels, CPAP-therapy for the respiratory support at home for 3 months, monitoring of the sleep scores, serum melatonin, and daytime sleepiness after the treatment.Results. A comparative assessment of the sleep scores before and after the respiratory support for 3 months revealed a significant improvement in sleep structure, elimination of the apnea episodes, and restoration of blood SрO2 after the therapy. Analysis of the serum melatonin vales confirmed a statistically significant increase of melatonin level against baseline in patients with SOAS after the treatment. A correlation analysis showed a relationship between the melatonin level, daytime sleepiness, and blood SрO2.Conclusion. The results of this study and the data of other researchers demonstrate that the elimination of intermittent nocturnal hypoxia in patients with SOAS allows reducing the morning serum melatonin level, thereby reducing the daytime sleepiness and subsequently improving the quality of life.