title: Fibroblast growth factor 21 (FGF-21) and its relation to obesity, metabolic syndrome, and nonalcoholic fatty liver in children: a longitudinal analysis.
abstract: BACKGROUND
  Fibroblast growth factor 21 (FGF-21), a potent activator of glucose uptake, has been proposed to be related to insulin resistance, metabolic syndrome (MetS), nonalcoholic fatty liver disease (NAFLD), and weight status.
  
  
  OBJECTIVE
  Our objective was to study the relationships between FGF-21, parameters of MetS, and NAFLD before and after weight loss in obese children.
  
  
  METHODS
  This was a cross-sectional comparison between obese and normal-weight children and longitudinal 1-yr follow-up study in obese children participating in a lifestyle intervention in a primary care setting.
  
  
  METHODS
  Patients included 60 obese and 40 lean children of same age, gender, and pubertal stage.
  
  
  METHODS
  The outpatient 1-yr intervention program was based on exercise, behavior, and nutrition therapy.
  
  
  METHODS
  We evaluated fasting serum FGF-21, weight status [body mass index (BMI) expressed as sd score (SDS)], body fat, insulin resistance index (homeostasis model assessment), leptin, transaminases, free fatty acids (FFA), waist circumference, blood pressure, and lipids.
  
  
  RESULTS
  Compared with the normal-weight children, obese children demonstrated significantly (P < 0.001) increased FGF-21, leptin, and homeostasis model assessment levels. FGF-21 was significantly (P < 0.05) correlated to BMI, SDS-BMI, FFA, and leptin both in cross-sectional and longitudinal analyses but not to any additional analyzed parameter. Children with and without MetS or NAFLD did not differ significantly with respect to their FGF-21 concentrations. A decrease of SDS-BMI was associated with a significant (P = 0.038) decrease of FGF-21 levels (mean -34%).
  
  
  CONCLUSIONS
  FGF-21 concentrations are reversibly increased in obese children and are related to leptin and FFA. However, our data do not support a significant relationship between FGF-21, insulin resistance, and features of MetS or NAFLD in children.
authors.affiliation: Department of Pediatric Nutrition Medicine, Vestische Hospital for Children and Adolescents Datteln, University of Witten/Herdecke, Dr. F. Steiner Strasse 5, D-45711 Datteln, Germany. T.Reinehr@kinderklinik-datteln.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinehr
authors.forename: Joachim
authors.initials: J
authors.lastname: Woelfle
authors.forename: Rainer
authors.initials: R
authors.lastname: Wunsch
authors.forename: Christian L
authors.initials: CL
authors.lastname: Roth
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005234:Fatty Liver / Q000378:metabolism* / Q000628:therapy; D005260:Female; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism* / Q000628:therapy; D065626:Non-alcoholic Fatty Liver Disease; D009765:Obesity / Q000378:metabolism* / Q000628:therapy*; D011320:Primary Health Care / Q000379:methods; D040242:Risk Reduction Behavior; D015431:Weight Loss / Q000502:physiology; D061217:Weight Reduction Programs
chemical_list: C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors