title: Morning cortisol levels and glucose metabolism parameters in moderate and severe obstructive sleep apnea patients.
abstract: Obstructive sleep apnea (OSA) has been associated with dysregulation of the hypothalamic-pituitary-adrenal axis and alterations in glucose metabolism with increased risk for type 2 diabetes. The aim of the current study was to compare morning plasma cortisol levels and glucose metabolism parameters between moderate (apnea-hypopnea index (AHI): 15-30 events/h) and severe OSA patients (AHI >30 events/h), with respective controls. A total of 56 male OSA patients, 24 moderate (AHI = 21.1 ± 5.3) and 32 severe (AHI = 49.7 ± 18.1), underwent a full-night polysomnography, oral glucose tolerance test (OGTT), and measurement of morning plasma cortisol levels. These groups were compared to 20 matched subjects in a control group. Morning plasma cortisol levels were statistically lower in severe OSA group than in moderate OSA and control groups (303.7 ± 93.5 vs. 423.9 ± 145.1 vs. 417.5 ± 99.8 pmol/L, P < 0.001). Significant negative correlations were found between morning plasma cortisol levels and AHI (r = -0.444, P = 0.002), as well as oxygen desaturation index (r = -0.381, P = 0.011). Fasting plasma glucose (5.0 ± 0.5 vs. 5.4 ± 0.7 vs. 4.9 ± 0.6 mmol/L, P = 0.009) was higher in the severe OSA group compared to moderate OSA and controls. Homeostasis model assessment insulin resistance (HOMA-IR) was higher in the severe OSA group compared to moderate OSA and controls (4.6 ± 3.7 vs. 2.7 ± 2.0 and 2.2 ± 1.8, respectively, P = 0.006). In conclusion, our study showed that morning plasma cortisol levels measured at 8 a.m. were significantly lower in severe OSA patients than those in moderate OSA group and controls. Morning plasma cortisol levels showed a negative correlation with AHI and oxygen desaturation index. Additionally, this study confirmed the evidence of glucose metabolism impairment in moderate and severe OSA patients, with more pronounced effect in the severe OSA patients group.
authors.affiliation: Department of Pathophysiology, University of Split School of Medicine, Soltanska 2, Split, Croatia.
authors.forename: Josko
authors.initials: J
authors.lastname: Bozic
authors.affiliation: Study of Dental Medicine, University of Split School of Medicine, Soltanska 2, Split, Croatia.
authors.forename: Tea
authors.initials: T
authors.lastname: Galic
authors.affiliation: Department of Medical Laboratory Diagnostics, University Hospital Split, Spinciceva 1, Split, Croatia.
authors.forename: Daniela
authors.initials: D
authors.lastname: Supe-Domic
authors.affiliation: Split Sleep Medicine Center, University of Split School of Medicine, Soltanska 2, Split, Croatia.
authors.forename: Natalija
authors.initials: N
authors.lastname: Ivkovic
authors.affiliation: Department of Pathophysiology, University of Split School of Medicine, Soltanska 2, Split, Croatia.
authors.forename: Tina
authors.initials: T
authors.lastname: Ticinovic Kurir
authors.affiliation: Department of Physiology, University of Split School of Medicine, Soltanska 2, Split, Croatia.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Valic
authors.affiliation: Departments of Anatomy and Neuroscience, University of Mostar School of Medicine, Bijeli brijeg bb, Mostar, Bosnia and Herzegovina.
authors.forename: Josip
authors.initials: J
authors.lastname: Lesko
authors.affiliation: Split Sleep Medicine Center, University of Split School of Medicine, Soltanska 2, Split, Croatia. zdogas@gmail.com.|Department of Neuroscience, University of Split School of Medicine, Soltanska 2, Split, 21000, Croatia. zdogas@gmail.com.
authors.forename: Zoran
authors.initials: Z
authors.lastname: Dogas
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000175:diagnosis
chemical_list: D001786:Blood Glucose; D007328:Insulin; D006854:Hydrocortisone
keywords: Glucose metabolism; Insulin resistance; Morning plasma cortisol levels; Obstructive sleep apnea; Pre-diabetes