title: Relationship between serum vitamin D, disease severity, and airway remodeling in children with asthma.
abstract: BACKGROUND
  Little is known about vitamin D status and its effect on asthma pathophysiology in children with severe, therapy-resistant asthma (STRA).
  
  
  OBJECTIVE
  Relationships between serum vitamin D, lung function, and pathology were investigated in pediatric STRA.
  
  
  METHODS
  Serum 25-hydroxyvitamin D [25(OH)D(3)] was measured in 86 children (mean age, 11.7 yr): 36 with STRA, 26 with moderate asthma (MA), and 24 without asthma (control subjects). Relationships between 25(OH)D(3), the asthma control test (ACT), spirometry, corticosteroid use, and exacerbations were assessed. Twenty-two of 36 children with STRA underwent fiberoptic bronchoscopy, bronchoalveolar lavage, and endobronchial biopsy with assessment of airway inflammation and remodeling.
  
  
  RESULTS
  25(OH)D(3) levels (median [IQR]) were significantly lower in STRA (28 [22-38] nmol/L) than in MA (42.5 [29-63] nmol/L) and control subjects (56.5 [45-67] nmol/L) (P < 0.001). There was a positive relationship between 25(OH)D(3) levels and percent predicted FEV(1) (r = 0.4, P < 0.001) and FVC (r = 0.3, P = 0.002) in all subjects. 25(OH)D(3) levels were positively associated with ACT (r = 0.6, P < 0.001), and inversely associated with exacerbations (r = -0.6, P < 0.001) and inhaled steroid dose (r = -0.39, P = 0.001) in MA and STRA. Airway smooth muscle (ASM) mass, but not epithelial shedding or reticular basement membrane thickness, was inversely related to 25(OH)D(3) levels (r = -0.6, P = 0.008). There was a positive correlation between ASM mass and bronchodilator reversibility (r = 0.6, P = 0.009) and an inverse correlation between ASM mass and ACT (r = -0.7, P < 0.001).
  
  
  CONCLUSIONS
  Lower vitamin D levels in children with STRA were associated with increased ASM mass and worse asthma control and lung function. The link between vitamin D, airway structure, and function suggests vitamin D supplementation may be useful in pediatric STRA.
authors: Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK. atulgupta@doctors.org.uk
authors: Atul
authors: A
authors: Gupta
authors: Alies
authors: A
authors: Sjoukes
authors: David
authors: D
authors: Richards
authors: Winston
authors: W
authors: Banya
authors: Catherine
authors: C
authors: Hawrylowicz
authors: Andrew
authors: A
authors: Bush
authors: Sejal
authors: S
authors: Saglani
mesh_terms: D000293:Adolescent; D056151:Airway Remodeling; D001249:Asthma / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology*; D016022:Case-Control Studies; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012129:Respiratory Function Tests; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D