title: [Normal values of bone turnover markers in childhood].
abstract: OBJECTIVE
  To determine the normal profile of bone turnover markers in childhood in order to enable evaluation of bone mineralization status in the healthy pediatric population and in the population at risk of osteoporosis.
  
  
  METHODS
  A population of 75 healthy children aged between 6 months and 14 years was studied. Levels of osteocalcin and C-terminal procollagen peptide type I, as markers of bone apposition, were determined in serum. Levels of hydroxyproline and pyridinoline, as markers of bone resorption, were determined in urine samples. Statistical analysis of the results was performed.
  
  
  RESULTS
  The highest levels of the four markers were obtained in the first 4 years of life. Markers of bone resorption showed a continuous statistically significant decrease until the age of 14 years (p < 0.05), whereas markers of bone apposition decreased slightly after the age of 4 years and then remained stable until the age of 14 years.
  
  
  CONCLUSIONS
  These findings are compatible with the presence of intense bone turnover in the first 4 years of life and with a predominance of the phenomenon of bone apposition throughout the first 14 years of life. Knowledge of the normal profile of these markers allows evaluation of bone mineralization status in the healthy pediatric population and in the population at risk of osteoporosis.
authors.affiliation: Unidad de Enfermedades Metabólicas, Hospital Universitario Miguel Servet, Zaragoza, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Manjón Llorente
authors.forename: C
authors.initials: C
authors.lastname: Fernández-Espuelas
authors.forename: J Ma
authors.initials: JM
authors.lastname: González López
authors.forename: M P
authors.initials: MP
authors.lastname: Ruiz-Echarri
authors.forename: A
authors.initials: A
authors.lastname: Baldellou Vázquez
mesh_terms: D000293:Adolescent; D000596:Amino Acids / Q000652:urine; D001842:Bone and Bones / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D006909:Hydroxyproline / Q000652:urine; D007223:Infant; D015675:Osteocalcin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D012016:Reference Values; D013030:Spain
chemical_list: D000596:Amino Acids; D010446:Peptide Fragments; D011347:Procollagen; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; C015484:pyridinoline; D006909:Hydroxyproline