title: The frequency of vitamin D deficiency in adults with Crohn's disease.
abstract: BACKGROUND
  Vitamin D deficiency is a putative, pathogenic cofactor in the increase in osteopenia and osteoporosis seen in patients with Crohn's disease.
  
  
  OBJECTIVE
  To determine the frequency of low serum 25-hydroxy-vitamin D3 (25-OHD) levels and the associated alterations in bone mineral density in a cohort of adults with Crohn's disease.
  
  
  METHODS
  25-OHD levels were determined in 242 consecutive patients with Crohn's disease seen in two tertiary inflammatory bowel disease referral centres. Bone mineral density was assessed by dual energy x-ray absorptiometry.
  
  
  RESULTS
  Nineteen (8%) patients exhibited vitamin D deficiency (25-OHD less than 25 nmol/L) and 52 (22%) patients exhibited vitamin D insufficiency (25-OHD less than 40 nmol/L). Mean T-scores at the lumbar spine, femoral neck, total hip and ultradistal radius in the group with low 25-OHD did not differ from those of the normal 25-OHD group. Serum alkaline phosphatase and parathyroid hormone levels were higher in the low 25-OHD group than in the normal group. Decreased red blood cell (RBC) folate predicted low 25-OHD in male patients, while smoking, RBC folate and serum iron predicted low 25-OHD in female patients. The rate of low 25-OHD deficiency in the winter was significantly higher than that in the summer (11.9% versus 2.8%, respectively).
  
  
  CONCLUSIONS
  Vitamin D-deficient Crohn's disease patients exhibit biochemical evidence of metabolic bone disease, without detectable differences in bone mineral density. Sunlight exposure, nutrition and smoking status were predictors of vitamin D deficiency in this patient cohort.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton.
authors.forename: Jesse S
authors.initials: JS
authors.lastname: Siffledeen
authors.forename: Kerry
authors.initials: K
authors.lastname: Siminoski
authors.forename: Hillary
authors.initials: H
authors.lastname: Steinhart
authors.forename: Gordon
authors.initials: G
authors.lastname: Greenberg
authors.forename: Richard N
authors.initials: RN
authors.lastname: Fedorak
mesh_terms: D000328:Adult; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000097:blood / Q000209:etiology; D002112:Calcifediol / Q000097:blood / Q000172:deficiency*; D015331:Cohort Studies; D003424:Crohn Disease / Q000097:blood / Q000150:complications*; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood / Q000209:etiology*; D012307:Risk Factors
chemical_list: D002112:Calcifediol