title: Dynamics of bone turnover in children with GH deficiency treated with GH until final height.
abstract: OBJECTIVE
  To examine the dynamics of bone turnover in children with growth hormone deficiency (GHD) during long-term treatment.
  
  
  METHODS
  We longitudinally measured growth velocity and serum concentrations of osteocalcin (OC), carboxyterminal propeptide of type I procollagen (PICP), and cross-linked carboxyterminal telopeptide of type I collagen (ICTP) in 24 patients with GHD during long-term GH treatment until final height (age: 7.7+/-0.7 and 16.9+/-0.5 years at baseline and at final height respectively).
  
  
  RESULTS
  At baseline, OC, PICP, and ICTP levels were significantly (P<0.0001) reduced in comparison with prepubertal bone age-matched controls (10.2+/-2.3 microgram/l and 22.5+/-7.6 microgram/l; 187.8+/-26.2 microgram/l and 328. 4+/-74.3 microgram/l; 7.7+/-2.0 microgram/l and 14.2+/-1.3 microgram/l respectively). During the first year of treatment mean levels of the bone markers increased significantly (P<0.0001) with a peak at 12 months. After the first year of treatment, OC and PICP levels progressively declined, whereas ICTP levels remained stable until the final height; in any case, bone marker levels remained significantly higher (P<0.03-P<0.0001) than baseline. The change in bone marker levels at 6 and 12 months of treatment with respect to the baseline values was not related to growth rate during long-term treatment or final height.
  
  
  CONCLUSIONS
  The results show that children with GHD have reduced bone turnover at baseline, and that long-term GH treatment is associated with a stimulation of bone turnover. OC, PICP, and ICTP do not predict growth rate during long-term treatment or final height in children with GHD.
authors.affiliation: Endocrine Unit, Division of Pediatrics, Department of Reproductive Medicine and Pediatrics, University of Pisa, Pisa, Italy.
authors.forename: G I
authors.initials: GI
authors.lastname: Baroncelli
authors.forename: S
authors.initials: S
authors.lastname: Bertelloni
authors.forename: C
authors.initials: C
authors.lastname: Ceccarelli
authors.forename: D
authors.initials: D
authors.lastname: Cupelli
authors.forename: G
authors.initials: G
authors.lastname: Saggese
mesh_terms: D000293:Adolescent; D001827:Body Height / Q000187:drug effects*; D016723:Bone Remodeling; D003094:Collagen / Q000097:blood; D024042:Collagen Type I; D005260:Female; D013006:Growth Hormone / Q000172:deficiency* / Q000627:therapeutic use*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides / Q000097:blood; D011347:Procollagen / Q000097:blood
chemical_list: D024042:Collagen Type I; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; D013006:Growth Hormone; D003094:Collagen