title: Vitamin D deficiency and reduced lung function in connective tissue-associated interstitial lung diseases.
abstract: BACKGROUND
  Vitamin D is a steroid hormone with pleiotropic effects including immune system modulation, lung tissue remodeling, and bone health. Vitamin D deficiency has been implicated in the development of autoimmune diseases. We sought to evaluate the prevalence of vitamin D deficiency in a cohort of patients with interstitial lung disease (ILD) and hypothesized that vitamin D deficiency would be associated with an underlying connective tissue disease (CTD) and reduced lung function.
  
  
  METHODS
  Patients in the University of Cincinnati ILD Center database were evaluated for serum 25-hydroxyvitamin D levels as part of a standardized protocol. Regression analysis evaluated associations between 25-hydroxyvitamin D levels and other variables.
  
  
  RESULTS
  One hundred eighteen subjects were included (67 with CTD-ILD, 51 with other forms of ILD). The overall prevalence of vitamin D deficiency and insufficiency in the study population was 38% and 59%, respectively. Those with CTD-ILD were more likely to have vitamin D deficiency (52% vs 20%, P < .0001) and insufficiency (79% vs 31%, P < .0001) than other forms of ILD. Diminished FVC was associated with lower 25-hydroxyvitamin D(3) levels (P = .01). The association between vitamin D insufficiency and CTD-ILD persisted (OR, 11.8; P < .0001) after adjustment for potential confounders. Among subjects with CTD-ILD, reduced 25-hydroxyvitamin D(3) levels were strongly associated with reduced lung function (FVC, P = .015; diffusing capacity for carbon monoxide, P = .004).
  
  
  CONCLUSIONS
  There is a high prevalence of vitamin D deficiency in patients with ILD, particularly those with CTD-ILD, and it is associated with reduced lung function. Vitamin D may have a role in the pathogenesis of CTD-ILD.
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Jared T
authors.initials: JT
authors.lastname: Hagaman
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Panos
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Francis X
authors.initials: FX
authors.lastname: McCormack
authors.affiliation: Division of Nephrology and Hypertension, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Charuhas V
authors.initials: CV
authors.lastname: Thakar
authors.affiliation: Department of Pathology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Wikenheiser-Brokamp
authors.affiliation: Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, OH.
authors.forename: Ralph T
authors.initials: RT
authors.lastname: Shipley
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, University of Cincinnati College of Medicine, Cincinnati, OH. Electronic address: brent.kinder@uc.edu.
authors.forename: Brent W
authors.initials: BW
authors.lastname: Kinder
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003240:Connective Tissue Diseases / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D017563:Lung Diseases, Interstitial / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012044:Regression Analysis; D012129:Respiratory Function Tests; D014808:Vitamin D Deficiency / Q000150:complications* / Q000453:epidemiology / Q000503:physiopathology*