title: Fibroblast growth factor 21 (FGF-21) in obese children: no relationship to growth, IGF-1, and IGFBP-3.
abstract: BACKGROUND
  Fibroblast growth factor 21 (FGF-21) is a hepatic protein that plays a critical role in liver, adipose tissue, and bone metabolism. Animal models reported an increase of FGF-21 and associated growth disturbances in undernutrition. Therefore, we studied the impact of weight loss in obese children on growth, FGF-21, and insulin-like factor 1 (IGF-1) concentrations.
  
  
  METHODS
  We analyzed height, serum concentrations of FGF-21, IGF-1, IGFBP-3, leptin, and insulin at baseline and 1 year later in 30 obese children with substantial weight loss (reduction >0.5 BMI-SDS) and in 30 obese children of similar age, gender, and pubertal stage with stable BMI-SDS. All children participated in a 1-year lifestyle intervention. Height and IGF-1 was transformed to standard deviation score (SDS). Multiple linear regression analyses adjusted for age, gender, and pubertal stage were performed.
  
  
  RESULTS
  At baseline, height-SDS was significantly related to IGF-1-SDS (β-coefficient 0.68 95% confidence interval (95% CI)±0.49; p=0.008) and leptin (β-coefficient 0.042 95% CI±0.030; p=0.008), but not to FGF-21 or insulin. FGF-21 was not significantly associated with IGF-1 or IGFBP-3. In longitudinal analysis, changes of FGF-21 were not significantly related to changes of height, IGF-1-SDS or IGFBP-3. However, in the subgroup of 30 children with substantial BMI-SDS reduction, FGF-21, leptin, insulin, and HOMA decreased significantly.
  
  
  CONCLUSIONS
  As there was no significant association between FGF-21 and growth or IGF-1 both in cross-sectional and longitudinal analyses, these findings do not support the hypothesis that FGF-21 is involved in growth of obese children. Further studies are necessary to understand the multiple alterations in the growth hormone (GH) axis in obese children.
authors.affiliation: .
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinehr
authors.affiliation: .
authors.forename: Christian L
authors.initials: CL
authors.lastname: Roth
authors.affiliation: .
authors.forename: Joachim
authors.initials: J
authors.lastname: Woelfle
mesh_terms: D000293:Adolescent; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D020738:Leptin / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000097:blood* / Q000175:diagnosis; D015431:Weight Loss
chemical_list: C515497:IGFBP3 protein, human; D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D020738:Leptin; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors; D007334:Insulin-Like Growth Factor I
keywords: FGF-21; IGF-1; IGFBP-3; children; growth; height; insulin; leptin; obesity; weight loss