Changes And Implication Of Serum Melatonin Level In Patients With Obstructive Sleep Apnea-hypopnea Syndrome

Objective:To explore the changes and implications of serum melatonin levels in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS).Method:In total,30 patients with OSAHS and 10 healthy controls were studied from the First Hospital of Lanzhou University, and were assessed by the Epworth Sleepiness Scale. Serum melatonin levels were determined at 23:30,02:00,07:00 and 11:00 in patients and control subjects. High performance liquid chromatography with fluorescence detection was used to determinate the melatonin level in serum.Results:The control subjects showed a nocturnal melatonin peak value at 02:00(93.37+ 19.31) pg/ml. However, this nocturnal melatonin peak was absent in the OSAS patients (34.95±18.96) pg/ml. At 07:00,the melatonin level in the OSAHS group(45.08±20.57) pg/ml was no significant difference than those in the control group[(52.43±13.15) pg/ml (p>0.05)].At 11:00, the melatonin level in the OSAHS group (37.07±17.46) pg/ml was no significant difference than those in the control group[(38.48±8.25)pg/ml(p>0.05)].At 22:30 and 11:00 the melatonin concentration in OSAHS group did not correlated with AHI, MSaO2 and LSaO2(r 22:30= 0.144,-0.133,-0.133, p> 0.05; r11:00=0.151,-0.010,-0.326, p> 0.05). But at 02:00 and 07:00 the serum melatonin levels in OSAHS group correlated negatively with the AHI (r=-0.694,-0.593, p<0.01), and correlated positively with MSaO2(r=0.391,0.501,p <0.01), and correlated positively with LSaO2 (r=0.442,0.484, p>0.05). At 22:30, the melatonin concentration in OSAHS group did not correlated with ESS(r=0.153,p> 0.05). At 02:00 and 07:00, the melatonin concentration in OSAHS group correlated negatively with ESS(r=-0.468,-0.518, p< 0.05). At 11:00 the serum melatonin levels in patients with OSAH showed a negative correlation with ESS (r=-646, p< 0.05).Conclusion:Patients with OSAHS have an abnormal melatonin secretion pattern. And the serum melatonin levels are decreased which maybe related to oxidative stress induced by intermittent hypoxia. Melatonin may be involved in the mechanism of daytime sleepiness in patients with OSAHS.