title: Relationships of serum leptin levels with biochemical markers of bone turnover and with growth factors in normal weight and overweight children.
abstract: OBJECTIVE
  To examine the hypothesis of an influence of leptin on growth factors and on biochemical markers of bone turnover of prepubertal overweight children.
  
  
  METHODS
  395 prepubertal children, 6-13 years of age, were selected and the relationships between circulating serum levels of leptin and insulin-like growth factor I (IGF-I), insulin growth factor binding protein-3 (IGFBP-3) and some biochemical markers of bone turnover (osteocalcin, OC; carboxyterminal propeptide of type I procollagen, PICP, and carboxyterminal propeptide of type I collagen, ICTP) were analyzed. The subjects were subdivided into normal weight (NW, n = 163) and weight excess (WE, n = 232) subjects.
  
  
  CONCLUSIONS
  Significant differences between the two groups were found for leptin (p < 0.01), IGF-I (p < 0.01) and IGFBP-3 (p < 0.01), with higher values in WEs, and for OC (p < 0.01) with higher values in NWs. A significant reduction of leptin (p < 0.01) and IGFBP-3 (p < 0.01) serum values and an increase of those of OC (p < 0.01) and PICP (p < 0.05), but not of ICTP, were registered in 103 WEs who showed a drop in weight excess during a weight-excess reduction program. No variations were observed in 26 non-responsive subjects. In a multivariate analysis in which leptin, corrected by BMI and sex, was the independent variable, a significant negative correlation was found with PICP (beta = -0.235, p < 0.01), IGF-I (beta = -0.180, p < 0.01) and height velocity (beta = -0.155, p < 0.01). There was no correlation with OC, ICTP and IGFBP-3. The results demonstrate that nutritional status and leptin levels are involved in the regulation of growth factors and biochemical markers of bone formation.
authors.affiliation: Paediatric Endocrine and Diabetic Unit, Department of Gynaecologic, Obstetric and Paediatric Sciences, University of Perugia, Azienda Ospedaliera Policlinico Monteluce, Via Brunamonti, IT-06100 Perugia, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Bini
authors.forename: Giampiero
authors.initials: G
authors.lastname: Igli Baroncelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Papi
authors.forename: Federica
authors.initials: F
authors.lastname: Celi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Saggese
authors.forename: Adriano
authors.initials: A
authors.lastname: Falorni
mesh_terms: D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D016723:Bone Remodeling; D016022:Case-Control Studies; D002648:Child; D024042:Collagen Type I; D005260:Female; D006133:Growth Substances / Q000097:blood*; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood*; D008297:Male; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood* / Q000473:pathology / Q000628:therapy; D015675:Osteocalcin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides; D011347:Procollagen / Q000097:blood; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D006133:Growth Substances; D018972:Insulin-Like Growth Factor Binding Protein 3; D020738:Leptin; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I