title: Pediatric 25-hydroxyvitamin D concentrations in neurofibromatosis type 1.
abstract: OBJECTIVE
  Low 25-hydroxyvitamin D (25OHD) concentrations have been associated with tumors and osteopenia or fractures in adults with neurofibromatosis type 1 (NF1). We report 25OHD concentrations in 109 children with NF1 and 218 controls matched for age, sex, geographic location, and time of year.
  
  
  METHODS
  Children with NF1 were recruited (n=109; 2-17 years), and clinical data and dual-energy X-ray absorptiometry measurements were obtained. 25OHD concentrations were measured in subjects and controls.
  
  
  RESULTS
  More NF1 individuals (50%) were in the 25OHD insufficient or deficient range (<30 ng/mL) (1 ng/mL = 2.496 nmol/L) compared to controls (36%) (p = 0.0129). 25OHD concentrations were higher in individuals with neurofibromas after controlling for age (p = 0.0393), and were negatively associated with whole-body subtotal bone mineral density (BMD) z-scores (p = 0.0385).
  
  
  CONCLUSIONS
  More children with NF1 had 25OHD concentrations <30 ng/mL, potentially because of increased pigmentation and/or decreased sunlight exposure. In contrast to adults, decreased 25OHD concentrations were not associated with neurofibromas, and there was no positive association between 25OHD and BMD.
authors.affiliation: Department of Pediatrics, University of Utah, Salt Lake City, UT 84132, USA. david.stevenson@hsc.utah.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Stevenson
authors.forename: David H
authors.initials: DH
authors.lastname: Viskochil
authors.forename: John C
authors.initials: JC
authors.lastname: Carey
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Sheng
authors.forename: Mary
authors.initials: M
authors.lastname: Murray
authors.forename: Laurie
authors.initials: L
authors.lastname: Moyer-Mileur
authors.forename: Judd
authors.initials: J
authors.lastname: Shelton
authors.forename: William L
authors.initials: WL
authors.lastname: Roberts
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Bunker
authors.forename: Heather
authors.initials: H
authors.lastname: Hanson
authors.forename: Stephanie
authors.initials: S
authors.lastname: Bauer
authors.forename: Jacques L
authors.initials: JL
authors.lastname: D'Astous
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009456:Neurofibromatosis 1 / Q000097:blood* / Q000175:diagnosis; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D051598:Whole Body Imaging
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D