title: Steroid requirements and immune associations with vitamin D are stronger in children than adults with asthma.
abstract: BACKGROUND
  The effects of serum vitamin D status on atopy, steroid requirement, and functional responsiveness to corticosteroids in children versus adults with asthma have not been studied systematically.
  
  
  OBJECTIVE
  We sought to explore the age-specific effects of vitamin D in asthmatic patients.
  
  
  METHODS
  Serum vitamin D levels were examined in a prospective study of adults and children (102 healthy control subjects and 103 asthmatic patients). PBMCs were cultured for 3 hours with or without 100 nmol/L dexamethasone, and the expression of corticosteroid-regulated genes was detected by using real-time PCR. Serum IgE levels were measured, and information about asthmatic patients' steroid requirements was collected.
  
  
  RESULTS
  Deficient serum vitamin D levels (<20 ng/mL) were found in 47.6% of asthmatic patients and 56.8% of healthy control subjects, with means ± SDs of 20.7 ± 9.8 and 19.2 ± 7.7 ng/mL, respectively. In multivariate regression models a significant positive correlation between serum vitamin D levels and the expression of vitamin D-regulated targets, cytochrome P450, family 24, subfamily a (cyp24a) expression by PBMCs (P = .0084, pediatric asthma group only) and serum LL-37 levels (P = .0006 in the pediatric group but P = .0067 in the adult asthma group), was found. An inverse association between vitamin D and serum IgE levels was observed in the pediatric (P = .006) asthma group. Serum vitamin D level (P = .05), as well as PBMC cyp24a expression (P = .0312), demonstrated a significant inverse relationship with daily inhaled corticosteroid dose in the pediatric asthma group only. Cyp24a expression in PBMCs correlated positively with in vitro suppression of TNF-α by dexamethasone (P = .05) and IL-13 (P = .0094) in PBMCs in the pediatric asthma group only.
  
  
  CONCLUSIONS
  This study demonstrated significant associations between serum vitamin D status and steroid requirement and in vitro responsiveness to corticosteroids in the pediatric but not the adult asthma group. Vitamin D was also related to IgE levels in children but not in adults.
authors.affiliation: Division of Pediatric Allergy and Immunology, National Jewish Health, Denver, CO, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Goleva
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Searing
authors.forename: Leisa P
authors.initials: LP
authors.lastname: Jackson
authors.forename: Brittany N
authors.initials: BN
authors.lastname: Richers
authors.forename: Donald Y M
authors.initials: DY
authors.lastname: Leung
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D000367:Age Factors; D001249:Asthma / Q000097:blood* / Q000188:drug therapy* / Q000276:immunology*; D002478:Cells, Cultured; D002648:Child; D003907:Dexamethasone / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D018793:Interleukin-13 / Q000235:genetics / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013250:Steroid Hydroxylases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D014807:Vitamin D / Q000097:blood*; D065668:Vitamin D3 24-Hydroxylase; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D018793:Interleukin-13; D014409:Tumor Necrosis Factor-alpha; D014807:Vitamin D; D007073:Immunoglobulin E; D003907:Dexamethasone; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase