title: Obstructive sleep apnoea, cigarette smoking and plasma orexin-A in a sleep clinic cohort.
abstract: Orexin-A is a neuropeptide involved in the regulation of food intake and the sleep-wake cycle. This study investigated plasma orexin-A levels in a sleep clinic cohort, adjusting for smoking habits, in 76 participants comprising 41 with obstructive sleep apnoea (OSA) (apnoea-hypopnoea index [AHI] 44.1 +/- 19.1 events/h) and 35 without OSA (AHI 6.3 +/- 4.7 events/h). Plasma orexin-A levels were significantly lower in OSA patients (15.0 +/- 4.6 ng/ml) compared with those without OSA (31.4 +/- 6.5 ng/ml). In non-OSA subjects, there was no significant difference between never smokers and ex/current smokers in plasma orexin-A levels (32.9 +/- 9.5 versus 29.7 +/- 8.9 ng/ml, respectively) whereas, in the OSA sub-group, orexin-A levels were significantly lower in never smokers than in ex/current smokers (4.0 +/- 1.2 versus 21.4 +/- 7.0 ng/ml). A significant inverse relationship was found between plasma orexin-A levels and AHI amongst never smokers, but there was no significant relationship amongst ex/current smokers. These results confirm previous studies demonstrating lower levels of plasma orexin-A in OSA patients and indicate that smoking may affect orexin-A levels and AHI.
authors.affiliation: Sleep Disorders Centre, Department of Pulmonology, Atatürk Chest Diseases and Chest Surgery Education and Research Hospital, Ankara, Turkey. kurtulusaksu@yahoo.com
authors.forename: K
authors.initials: K
authors.lastname: Aksu
authors.forename: S
authors.initials: S
authors.lastname: Firat Güven
authors.forename: F
authors.initials: F
authors.lastname: Aksu
authors.forename: B
authors.initials: B
authors.lastname: Ciftci
authors.forename: T
authors.initials: T
authors.lastname: Ulukavak Ciftci
authors.forename: S
authors.initials: S
authors.lastname: Aksaray
authors.forename: T
authors.initials: T
authors.lastname: Sipit
authors.forename: Y
authors.initials: Y
authors.lastname: Peker
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009479:Neuropeptides / Q000097:blood*; D000068797:Orexins; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000503:physiopathology*; D012907:Smoking / Q000097:blood* / Q000503:physiopathology*
chemical_list: C000596229:HCRT protein, human; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins