Obstructive sleep apnoea syndrome is associated with relative hypocortisolemia and decreased hypothalamo–pituitary–adrenal axis response to 1 and 250 μg ACTH and glucagon stimulation tests

The investigations regarding the effect of obstructive sleep apnoea syndrome (OSAS) on hypothalamo–pituitary–adrenal (HPA) axis revealed conflicting results. We aimed to evaluate the effects of OSAS on HPA-axis with dynamic tests. This study was carried out on 26 patients with OSAS and 15 subjects without OSAS which, were defined according to the International Classification of Sleep Disorders. Patients were enrolled from either Endocrinology outpatient clinic or Neurology Sleep Center. Participants for the control group were included from the patients admitting to Endocrinology Department with the complaint of obesity or volunteers from hospital staff. All the participants were evaluated by polysomnography (PSG) and dynamic tests of HPA axis (dexamethasone suppression test, 1 and 250 μg ACTH and glucagon stimulation tests). Serum basal and peak cortisol levels were found to be lower in OSAS patients when compared to the control group during 1 μg ACTH and glucagon stimulation tests. When the area under curve (AUC) of cortisol responses to dynamic stimulation tests were calculated according to trapezoid formula, patients with OSAS were found to have lower values compared to control group. AUC responses of all three dynamic stimulation tests were found to be negatively correlated with AHI. OSAS is associated with relative hypocortisolemia in the morning with reduced responses to 1 and 250 μg ACTH and glucagon stimulation tests.