Melatonin levels in sleep apnea - the effect of bilevel positive airway pressure therapy

Background: Sleep apnea is linked with repetitive episodes of desaturation, disturbed sleep architecture, chronic stress, impaired melatonin regulation. Further knowledge on the physiology of melatonin secretion in sleep apnea, and the effect of possitive pressure treatment, could provide new therapeutic approach to the patients. Aim: The aim of the study is to examine the pattern of melatonin secretion in patients with sleep apnea, compared to healthy controls, and to evaluate the effect of BPAP therapy on melatonin levels. Materials and methods: this prospective study includes 76 individuals – 53 patients and 19 controls. Polysomnography was used to evaluate sleep architecture and disturbances in breathing. Melatonin direct saliva test was used in 31 patients and 15 controls to evaluate the pattern of melatonin secretion. Samples were taken at 2 a.m., 6 a.m., 2 p.m. and 22 p.m. Melatonin levels of 20 patients were followed up on the sixth month of therapy. Results: Melatonin levels in patients9 group are significantly higher in all investigated periods compared to the controls (figure 1). The pattern of melatonin secretion shows a higher peak during the night and does not reduce sufficiently in the morning. Melatonin levels in the afternoon are in correlation with the score on the daytime sleepines. 6-months therapy leads to reduction of melatonin levels and sleepiness to normal. Conclusion: BPAP therapy may lead to significant reduction of melatonin levels and influence daytime symptoms in sleep apnea.