title: Thyroid hormones and their relation to weight status.
abstract: OBJECTIVE
  The aim of this study was to analyze thyroid hormones in female adolescents with obesity and anorexia nervosa (AN) before and after normalization of weight.
  
  
  METHODS
  Thyroid-stimulating hormone (TSH), fT3, and fT4 were determined in 100 obese girls, 32 normal-weight girls and 20 girls with AN aged 14-18 years at baseline and 1 year later. Additionally, leptin, insulin, and the insulin resistance index HOMA were analyzed in the obese and normal-weight girls.
  
  
  RESULTS
  TSH and fT3 levels of girls with AN were significantly lower compared to TSH concentrations of normal-weight girls, while TSH and fT3 levels of the obese girls were significantly higher. The 21 obese females with weight loss >5% demonstrated a significant decrease in fT3 and TSH, while the 9 adolescents with AN and weight gain >5% showed a significant increase in fT3 and TSH. Insulin and HOMA were not significantly correlated to TSH, fT3 and fT4, while leptin was correlated to TSH and fT3 in both cross-sectional and longitudinal analysis.
  
  
  CONCLUSIONS
  Thyroid function seems to be reversibly related to weight status with increased TSH and fT3 concentrations in obesity and decreased TSH and fT3 levels in AN. We hypothesize that leptin may be the link between weight status and TSH.
authors.affiliation: Department of Pediatric Endocrinology, Vestische Hospital for Children and Adolescents, University of Witten/Herdecke, Datteln, Germany. T.Reinehr@kinderklinik-datteln.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinehr
authors.forename: Adelbert
authors.initials: A
authors.lastname: Isa
authors.forename: Gideon
authors.initials: G
authors.lastname: de Sousa
authors.forename: Rainer
authors.initials: R
authors.lastname: Dieffenbach
authors.forename: Werner
authors.initials: W
authors.lastname: Andler
mesh_terms: D000293:Adolescent; D000856:Anorexia Nervosa / Q000097:blood* / Q000628:therapy; D001835:Body Weight; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D020738:Leptin / Q000097:blood; D009765:Obesity / Q000097:blood* / Q000628:therapy; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D007328:Insulin; D020738:Leptin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine