title: Thyroid function in obese children and adolescents.
abstract: OBJECTIVE
  Obesity is frequently associated with modifications of thyroid size and function. We evaluated the prevalence of thyroid function abnormalities and the effects of puberty and weight loss in obese children and adolescents.
  
  
  METHODS
  We examined 468 obese children (255 girls and 213 boys aged 3.7-17.9 years) and 52 normal-weight age-matched children as controls. TSH, fT3, fT4, fasting serum insulin and glucose were measured at baseline. fT3, fT4 and TSH were also measured after 6 months of lifestyle intervention in a subset of 43 patients.
  
  
  RESULTS
  109 obese children showed abnormal circulating thyroid hormone concentrations (84 had elevated fT3 levels, 15 elevated TSH, 6 elevated fT4, 3 elevated fT3 and TSH, and 1 elevated fT3, fT4 and TSH levels). Serum TSH and fT3 concentrations were positively correlated with BMI-SDS. The prevalence of patients with abnormal thyroid hormone concentrations was similar between sexes and between prepubertal and pubertal subjects. After 6 months of lifestyle intervention, thyroid hormone concentrations normalized in 27 of the patients with decreased BMI-SDS, and in 2 patients in whom BMI-SDS increased.
  
  
  CONCLUSIONS
  In obese children, an increased fT3 concentration is the most frequent thyroid function abnormality. Serum fT3 and TSH correlate with BMI. Moderate weight loss frequently restores these abnormalities.
authors.affiliation: Servizio di Endocrinologia Pediatrica, Ospedale Regionale per le Microcitemie, Cagliari, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Marras
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Casini
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pilia
authors.forename: Daniela
authors.initials: D
authors.lastname: Carta
authors.forename: Patrizia
authors.initials: P
authors.lastname: Civolani
authors.forename: Manuela
authors.initials: M
authors.lastname: Porcu
authors.forename: Anna Paola
authors.initials: AP
authors.lastname: Uccheddu
authors.forename: Sandro
authors.initials: S
authors.lastname: Loche
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008019:Life Style; D008297:Male; D009765:Obesity / Q000503:physiopathology* / Q000628:therapy; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine