title: Obstructive sleep apnea syndrome and its association with vitamin D deficiency.
abstract: BACKGROUND
  Obstructive sleep apnea syndrome (OSAS) is a widespread disorder characterized by recurrent, partial or complete episodes of apnea due to upper airway tract obstruction during sleeping period. Deficiency of vitamin D has roles in development of many diseases. Association between presence and severity of OSAS and vitamin D has recently gained research interest.
  
  
  OBJECTIVE
  The aim of our study was to investigate the association between serum 25-hydroxy [25 (OH)] vitamin D levels and severity of disease in patients with OSAS.
  
  
  METHODS
  One hundred and fifty OSAS patients (50 patients with mild, 50 with moderate, 50 with severe OSAS) who were diagnosed by polysomnography (PSG) and 32 non-OSAS controls who were referred to the Health Ministry Ankara Numune Training and Research Hospital, Endocrinology and Metabolism Department, from January 2010 to May 2011 were included in the study. Serum 25(OH)D, PTH, calcium and phosphorus levels were evaluated in all the patients who were recruited to the study.
  
  
  RESULTS
  There was no statistically significant difference in serum 25(OH)D levels between OSAS and controls (p>0.05). However, in subgroup analysis of OSAS, we found that the patients with severe OSAS had significantly lower levels of 25(OH)D as compared with other groups (p=0.003). Also, the number of patients with serum 25(OH)D deficiency (<10 μg/dl) were higher in OSAS group than in controls (p<0.05).
  
  
  CONCLUSIONS
  We found that when the severity of OSAS increases, 25(OH)D deficiency becomes more pronounced.
authors.affiliation: Turkish Ministry of Health, Ankara Numune Training and Research Hospital, Department of Endocrinology and Metabolism, Talatpasa Bulvari, Samanpazari, 06100-Ankara, Turkey. turkanmete@yahoo.com.
authors.forename: T
authors.initials: T
authors.lastname: Mete
authors.forename: Y
authors.initials: Y
authors.lastname: Yalcin
authors.forename: D
authors.initials: D
authors.lastname: Berker
authors.forename: B
authors.initials: B
authors.lastname: Ciftci
authors.forename: S F
authors.initials: SF
authors.lastname: Guven
authors.forename: O
authors.initials: O
authors.lastname: Topaloglu
authors.forename: H C
authors.initials: HC
authors.lastname: Yavuz
authors.forename: S
authors.initials: S
authors.lastname: Guler
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000150:complications*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
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