title: Low Vitamin D Levels in Children with Fractures: a Comparative Cohort Study.
abstract: BACKGROUND
  The currently accepted ranges for "normal" serum vitamin D have recently been challenged in adults on the basis that healthy bone metabolism requires higher levels of vitamin D than previously thought.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate whether a new "biologically based" classification based on 25(OH)vitamin D levels that invoke an endocrine biomarker response (<20 ng/mL for deficiency and <32 ng/mL for insufficiency) is more appropriate for children with fractures than historical criteria.
  
  
  METHODS
  Serum 25(OH)vitamin D levels were collected from 58 children with acute low-energy fractures from an outpatient orthopedic clinic from 2009 to 2012. These vitamin D levels were compared with a cohort of 103 children with chronic kidney disease (CKD) from an adjacent clinic, a condition with acknowledged low levels of vitamin D. Then, the prevalence of vitamin D sufficiency in the fracture cohort was evaluated and compared using both historical guidelines and newer biologically based criteria.
  
  
  RESULTS
  25(OH)vitamin D levels in the fracture cohort did not differ from levels in the CKD cohort (27.5 vs. 24.6 ng/mL) indicating a similar distribution of vitamin D levels. This finding was consistent when controlling for significant covariables using linear regression analyses. In the fracture cohort, there was a discrepancy between historical and biologically based criteria in 64% of children.
  
  
  CONCLUSIONS
  The results of the current study suggest that fracture patients are more frequently vitamin D deficient than previously thought. This finding is more readily apparent when newer biologically based criteria for vitamin D sufficiency are used.
authors.affiliation: Department of Pediatric Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Fabricant
authors.affiliation: Washington University in St. Louis, 660 S. Euclid Ave, Box 8233, St. Louis, MO 63310 USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Dy
authors.affiliation: New York Presbyterian Hospital/Weill Cornell Medical Center, 1300 York Ave, New York, NY 10065 USA.
authors.forename: Son H
authors.initials: SH
authors.lastname: McLaren
authors.affiliation: The Ohio State University College of Medicine, 338 W 10th Ave, Columbus, OH 43210 USA.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Rauck
authors.affiliation: Department of Pediatric Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA ; New York Presbyterian Hospital/Weill Cornell Medical Center, 1300 York Ave, New York, NY 10065 USA.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Ipp
authors.affiliation: Department of Pediatric Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors.forename: Shevaun M
authors.initials: SM
authors.lastname: Doyle
keywords: BMI; calcium; deficiency; fracture; insufficiency