title: Clinical review: Do glucocorticosteroids alter vitamin D status? A systematic review with meta-analyses of observational studies.
abstract: BACKGROUND
  Vitamin D supplementation is an important adjunct therapy for the prevention and management of glucocorticoid-induced osteoporosis. There has been little exploration of the relationship between glucocorticosteroid (GCS) use and serum 25-hydroxyvitamin D [25(OH)D].
  
  
  OBJECTIVE
  The aim of this study was to systematically explore how serum 25(OH)D is altered in adult patients receiving GCS.
  
  
  METHODS
  We reviewed Medline and Cinahl databases between January 1970 and August 2011.
  
  
  METHODS
  Experimental studies were included where 25(OH)D was measured in patients more than 18 yr of age receiving GCS therapy. Studies were excluded if patients received at least 400 IU/d (10 μg/d) vitamin D, if GCS treatment was less than 2-wk duration, if more than 50% of the study population received GCS for renal or hepatic disease or after transplant, or if the study population included patients with Cushing's syndrome. A consensus method was used to classify studies. Of identified studies, 3% met the selection criteria.
  
  
  METHODS
  Data were extracted by a single author. Study quality was assessed using criteria developed by the American Dietetic Association.
  
  
  RESULTS
  The weighted mean 25(OH)D (by sample size or sd) was 22.4 [95% confidence interval (CI), 19.4, 25.3] ng/ml and 21.0 (95% CI, 13.5, 28.5) ng/ml, respectively. Random effects meta-analysis was used to compare serum 25(OH)D in patients treated with GCS compared to steroid-naive controls (either healthy or with active disease) and in patients before and after GCS administration. Serum 25(OH)D in GCS users was on average -0.5 (95% CI, -1.0, -0.1) ng/ml lower than in healthy controls (P=0.03; I2=56.4%). Serum 25(OH)D did not differ between GCS users and disease controls [standardized mean difference=0.0 (95% CI, -0.2, 0.3) ng/ml; P=0.793; I2=16.2%].
  
  
  CONCLUSIONS
  The suboptimal concentrations of serum 25(OH)D found in adults receiving GCS are inadequate for prevention and management of glucocorticoid-induced osteoporosis. Recommendations for vitamin D supplementation should be adjusted accordingly.
authors.affiliation: Monash University, Department of Nutrition and Dietetics, Southern Clinical School of Medicine, Monash Medical Centre, Level 5, Block E, 246 Clayton Road, Clayton, Victoria, Australia 3168. zoe.davidson@monash.edu
authors.forename: Zoe E
authors.initials: ZE
authors.lastname: Davidson
authors.forename: Karen Z
authors.initials: KZ
authors.lastname: Walker
authors.forename: Helen
authors.initials: H
authors.lastname: Truby
mesh_terms: D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D010024:Osteoporosis / Q000097:blood / Q000139:chemically induced* / Q000188:drug therapy; D014807:Vitamin D / Q000097:blood* / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000139:chemically induced* / Q000188:drug therapy
chemical_list: D005938:Glucocorticoids; D014807:Vitamin D