title: Active Crohn's disease is associated with low vitamin D levels.
abstract: OBJECTIVE
  Crohn's disease prevalence increases with increasing latitude. Because most vitamin D comes from sunlight exposure and murine models of intestinal inflammation have demonstrated beneficial effects of 1,25-(OH)2 vitamin D treatment, we hypothesised that Crohn's disease activity is associated with low vitamin D levels.
  
  
  METHODS
  In a cross-sectional study of 182 CD patients and 62 healthy controls, we measured serum 25-OH vitamin D. Stratified analysis was used to compare 25-OH vitamin D levels with Crohn's disease activity index, C-reactive protein, smoking status, intake of oral vitamin D supplements and seasonal variation in CD patients and healthy controls.
  
  
  RESULTS
  Serum 25-OH vitamin D was inversely associated with disease activity: Median 25-OH vitamin D levels of Crohn's disease in remission, mildly, and moderately active diseases evaluated by Crohn's disease activity index were 64, 49, and 21 nmol/l (p<0.01) and by CRP 68, 76, and 35 nmol/l (p<0.05), respectively. Patients who took oral vitamin D supplementation had lower Crohn's disease activity index (p<0.05) and C-reactive protein (p=0.07) than non-users. Crohn's disease patients who smoked had lower vitamin D levels (51 nmol/l) than patients who did not smoke (76 nmol/l), p<0.01. Overall, Crohn's disease patients did not differ from healthy controls regarding 25-OH vitamin D levels.
  
  
  CONCLUSIONS
  Active Crohn's disease was associated with low serum 25-OH vitamin D. Patients who smoked had lower 25-OH vitamin D levels than patients who did not smoke, independently of disease activity.
authors: Department of Medicine V, Hepatology and Gastroenterology, Aarhus University Hospital, Denmark. Electronic address: soerjoer@rm.dk.
authors: Søren Peter
authors: SP
authors: Jørgensen
authors: Christian Lodberg
authors: CL
authors: Hvas
authors: Jørgen
authors: J
authors: Agnholt
authors: Lisbet Ambrosius
authors: LA
authors: Christensen
authors: Lene
authors: L
authors: Heickendorff
authors: Jens Frederik
authors: JF
authors: Dahlerup
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D003424:Crohn Disease / Q000097:blood*; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D012720:Severity of Illness Index; D012907:Smoking / Q000097:blood; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D014815:Vitamins; D014807:Vitamin D; D002097:C-Reactive Protein; C104450:25-hydroxyvitamin D
keywords: (TGF)-β; 1,25(OH)(2)D; 1,25-(OH)(2) vitamin D; 25-OH vitamin D; 25OHD; C-reactive protein; CD; CDAI; CRP; Crohn's disease; Crohn's disease activity index; INF-γ; Smoking; TNF-α; VDR; Vitamin D; interferon gamma; transforming growth factor; tumour necrosis factor alpha; vitamin D receptor