title: Vitamin D status of male OSAS patients improved after long-term CPAP treatment mainly in obese subjects.
abstract: The aim of this study was to evaluate the effect of one-year useful continuous positive airway pressure (CPAP) treatment on serum vitamin D levels in middle-aged men affected by obstructive sleep apnea syndrome (OSAS).
  
  
  
  This is a secondary investigation related to a previously published observational study about the effect of short-term CPAP therapy on serum vitamin D levels in severe OSAS (Apnea-Hypopnea Index - AHI- >30/h) patients. In the present study, we included patients participating to the previous investigation who repeated serum vitamin D assessment after one year of useful CPAP treatment, and compared to control a group of OSAS patients with scarce compliance to CPAP treatment. OSAS patients with beneficial use of CPAP treatment were distributed in obese (Body Mass Index - BMI ≥30) and non-obese (BMI < 30). Moreover, the mean change between baseline and one-year follow-up (Δ) of serum vitamin D levels was correlated with demographic, polygraphic and clinical data throughout a multiple regression analysis.
  
  
  
  We documented the significant increase of serum vitamin D levels after one year of CPAP treatment in the OSAS group (n = 39, p < 0.001) and in both subgroups of obese (n = 23, p < 0.01) and non-obese (n = 16, p < 0.01) OSAS patients. Conversely, OSAS patients with a scarce compliance to CPAP therapy did not change serum vitamin D levels after one year (n = 10, p > 0.05). OSAS patients with beneficial CPAP treatment showed higher vitamin D serum levels after one year and a more frequent shift from insufficient to sufficient vitamin D status compared to OSAS patients not adequately using CPAP treatment. In particular, the obese OSAS patients subgroup shifted from insufficient (≤20 ng/mL) to sufficient (>20 ng/mL) vitamin D status after CPAP therapy more than the non-obese OSAS patients subgroup (p < 0.05). We observed higher Δ of vitamin D serum levels, Epworth Sleepiness Scale score, and AHI in obese compared to non-obese OSAS patients. Finally, BMI obtained at baseline positively correlated with Δ of vitamin D serum levels.
  
  
  
  This study documented that long-term CPAP treatment is a viable therapeutic choice for correcting both sleep apnea condition and vitamin D deficiency in middle-aged male OSAS patients. Significantly, this effect was more evident in obese subjects and possibly represents a valid therapeutic strategy to ensure sufficient vitamin D levels in these patients, which frequently show a deficient vitamin D status.
authors.affiliation: Sleep Medicine Centre, Neurophysiopathology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy. Electronic address: dott.claudioliguori@yahoo.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Liguori
authors.affiliation: Sleep Medicine Centre, Neurophysiopathology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Izzi
authors.affiliation: Sleep Medicine Centre, Neurophysiopathology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy; Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Nicola Biagio
authors.initials: NB
authors.lastname: Mercuri
authors.affiliation: Neurology Unit, San Giovanni Addolorata Hospital, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Romigi
authors.affiliation: Fondazione Santa Lucia IRCCS, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Cordella
authors.affiliation: Department of Orthopedics and Traumatology, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Tarantino
authors.affiliation: Sleep Medicine Centre, Neurophysiopathology Unit, Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Placidi
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods; D006801:Humans; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010349:Patient Compliance; D017286:Polysomnography; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000628:therapy; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood
chemical_list: D014807:Vitamin D
keywords: Long-term CPAP; OSAS; Obesity; Vitamin D