title: Continuous Positive Airway Pressure Treatment Increases Serum Vitamin D Levels in Male Patients with Obstructive Sleep Apnea.
abstract: OBJECTIVE
  Recent studies report a link between obstructive sleep apnea (OSA) syndrome, low vitamin D levels, and high parathyroid hormone (PTH) concentrations. The aim of the current study is to evaluate the effect of 7-night continuous positive airway pressure (CPAP) therapy on serum vitamin D, PTH, and calcium levels in patients with severe OSA syndrome.
  
  
  METHODS
  Patients with severe OSA were enrolled into the study and compared to control subjects. Patients with OSA underwent CPAP therapy for 7 nights and were consequently divided into responders (OSA-R, mean residual AHI < 5/h) and nonresponders (OSA-nR, mean residual AHI > 5/h). Serum vitamin D, PTH, and calcium levels were measured at baseline in patients with severe OSA (apnea-hypopnea index > 30/h) and control subjects. Patients with OSA underwent a final morning blood sample after 7-night CPAP therapy.
  
  
  RESULTS
  We enrolled 90 patients with OSA into the study (65 OSA-R and 25 OSA-nR) compared to 32 control subjects. At baseline, lower vitamin D and higher PTH levels were detected in the OSA group compared to controls. After 7-night CPAP therapy, male OSA-R patients showed a significant increase in vitamin D levels. Conversely, female OSA-R patients did not show the same increase in vitamin D levels. It was also observed that OSA-nR subjects did not show modifications of serum markers after nCPAP-therapy.
  
  
  CONCLUSIONS
  The study demonstrates that short-term nCPAP treatment is able to promote the recovery of vitamin D homeostasis in male patients with OSA. The mediation of sexual hormones in regulating vitamin D is a possible explanation of the lack of recovery of vitamin D homeostasis in female patients with OSA as it often affects postmenopausal women.
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Liguori
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Romigi
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Izzi
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.|Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Nicola Biagio
authors.initials: NB
authors.lastname: Mercuri
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Cordella
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Enza
authors.initials: E
authors.lastname: Tarquini
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Giambrone
authors.affiliation: Fondazione Santa Lucia IRCCS, Rome, Italy.|University of Rome "Tor Vergata," Department of Systems Medicine, Neurology Unit, Rome, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Marciani
authors.affiliation: University of Rome "Tor Vergata," Department of Systems Medicine, Neurophysiopathology Unit, Sleep Medicine Centre, Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Placidi
mesh_terms: D015415:Biomarkers / Q000097:blood; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000628:therapy*; D014807:Vitamin D / Q000097:blood*
chemical_list: D015415:Biomarkers; D014807:Vitamin D
keywords: CPAP; OSA; PTH; calcium; vitamin D