title: Vitamin D depletion following burn injury in children: a possible factor in post-burn osteopenia.
abstract: BACKGROUND
  Children burned > 40% total body surface area (TBSA) have chronically low bone mineral density (BMD) and increased risk for fractures and adult-onset osteoporosis. Because they are advised to avoid sunlight to prevent burn scar hyperpigmentation, we hypothesized that they develop vitamin D depletion, which could contribute to post-burn osteopenia.
  
  
  METHODS
  We studied 24 children, ages 5-20 years, burned > or = 40% TBSA 7.1 +/- 3.8 (SD) years, range 1.9-13.3 years, previously (n = 12) and 2.0 +/- 0.2, range 1.4-2.1 years, previously (n = 12), of which half received recombinant human growth hormone during the first post-burn year. We measured lumbar spine BMD, serum 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), intact PTH (iPTH), and osteocalcin.
  
  
  RESULTS
  Serum 25(OH)D was low in 10/11 patients and 1,25(OH)2D was low in 5/11 at 7 years post-burn. Serum 25(OH)D was low in 10/12, while 1,25(OH)2D was low in 0/12 at 2 years; osteocalcin was low in 9/12 in the 7-year group; iPTH levels were in the lowest quartile in 5/12 patients at 7 years and 10/12 patients at 2 years. Serum 25(OH)D levels correlated with BMD z-scores, r = 0.53, p < 0.05, and inversely with iPTH levels, r = -0.66, p < 0.05, in the 7-year group.
  
  
  CONCLUSIONS
  Burned children have low circulating levels of 25(OH)D which correlated with BMD z-scores, suggesting that post-burn vitamin D depletion may play a role in the chronically low bone density observed in these children.
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch at Galveston and Shriners Burns Hospital, 77555-0352, USA. gklein@utmb.edu
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Klein
authors.forename: Craig B
authors.initials: CB
authors.lastname: Langman
authors.forename: David N
authors.initials: DN
authors.lastname: Herndon
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000209:etiology*; D002056:Burns / Q000097:blood / Q000150:complications*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D016014:Linear Models; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000209:etiology*
chemical_list: D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D015675:Osteocalcin