title: Establishment of reference intervals for bone markers in children and adolescents.
abstract: OBJECTIVE
  To determine age and gender specific reference intervals for bone markers.
  
  
  METHODS
  Morning blood samples were collected after overnight fast from 356 healthy children (6 to 18 year-old) for the determination of bone marker levels, PTH and vitamin D(3). Multiple regression analysis was done to assess the effect of factors that could influence the bone marker levels; the central 95% reference interval and their 90% CI were calculated.
  
  
  RESULTS
  After excluding samples when BMI-z -scores were <-2 or >+2, both vitamin D(3) and PTH levels were abnormal and from children who used steroids the remainder were partitioned using Tanner stage based chronological age. As expected the reference intervals show a significant variation with age and gender. All the bone marker levels, except total alkaline phosphatase, were significantly higher in puberty with vitamin D(3) >75nmol/L.
  
  
  CONCLUSIONS
  Vitamin D status, age and gender are important for establishing reference intervals of bone markers in healthy children.
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.forename: Esther
authors.initials: E
authors.lastname: Eapen
authors.forename: Susan
authors.initials: S
authors.lastname: Steele
authors.forename: Vijaylaxmi
authors.initials: V
authors.lastname: Grey
mesh_terms: D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D001842:Bone and Bones / Q000201:enzymology / Q000378:metabolism*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D012016:Reference Values; D012044:Regression Analysis; D012727:Sex Characteristics; D014807:Vitamin D / Q000097:blood
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; D014807:Vitamin D; D000469:Alkaline Phosphatase