title: Vitamin D, vitamin D binding protein, and longitudinal outcomes in COPD.
abstract: BACKGROUND
  Associations between Vitamin D3 [25(OH)D], vitamin D binding protein (VDBP) and chronic obstructive pulmonary disease (COPD) are previously reported. We aimed to further investigate these associations on longitudinal outcomes.
  
  
  METHODS
  426 COPD patients from western Norway, GOLD stage II-IV, aged 40-76, were followed every six-month from 2006 through 2009 with spirometry, bioelectrical impedance measurements and registration of exacerbation frequency. Serum 25(OH)D and VDBP levels were determined at study-entry by high-performance liquid chromatography coupled with mass spectrometry and enzyme immunoassays respectively. Yearly change in lung function and body composition was assessed by generalized estimating equations (GEE), yearly exacerbation rate by negative binomial regression models, and 5 years all-cause mortality by Cox proportional-hazard regression.
  
  
  RESULTS
  1/3 of the patients had vitamin D deficiency (<20ng/mL) and a greater decline in both FEV1 and FVC, compared to patients with normal levels; for FEV1 this difference only reached statistical significance in the 28 patients with the lowest levels (<10ng/mL, p = 0.01). Neither 25(OH)D nor VDBP levels predicted exacerbation rate, change in fat free mass index or risk of death.
  
  
  CONCLUSIONS
  Severe vitamin D deficiency may affect decline in lung function parameters in COPD. Neither 25(OH)D nor VDBP levels did otherwise predict markers of disease progression.
authors: Dept. of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Louise J P
authors: LJ
authors: Persson
authors: Dept. of Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Marianne
authors: M
authors: Aanerud
authors: Dept. of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Pieter S
authors: PS
authors: Hiemstra
authors: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway.
authors: Annika E
authors: AE
authors: Michelsen
authors: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; K.G. Jebsen Inflammatory Research Center, University of Oslo, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors: Thor
authors: T
authors: Ueland
authors: Dept. of Clinical Science, University of Bergen, Bergen, Norway.
authors: Jon A
authors: JA
authors: Hardie
authors: Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway; Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway; K.G. Jebsen Inflammatory Research Center, University of Oslo, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors: Pål
authors: P
authors: Aukrust
authors: Dept. of Clinical Science, University of Bergen, Bergen, Norway.
authors: Per S
authors: PS
authors: Bakke
authors: Dept. of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway; Dept. of Clinical Science, University of Bergen, Bergen, Norway.
authors: Tomas M L
authors: TM
authors: Eagan
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D012129:Respiratory Function Tests; D012306:Risk; D014807:Vitamin D / Q000097:blood*; D014809:Vitamin D-Binding Protein / Q000097:blood*
chemical_list: D014809:Vitamin D-Binding Protein; D014807:Vitamin D