title: Thyroid function in the nutritionally obese child and adolescent.
abstract: OBJECTIVE
  In recent years, there has been an increasing focus on thyroid function in obese children. There is controversy concerning whether the changes in the levels of thyroid hormones and thyroid-stimulating hormone (thyrotropin - TSH) in obesity are causes or consequences of weight status and whether these subtle differences merit treatment with thyroxine. This review aimed to study the prevalence of disturbed thyroid hormone and TSH values in childhood obesity and the underlying pathophysiologic mechanisms linking obesity to thyroid function.
  
  
  RESULTS
  In the past 18 months, four studies demonstrated moderate elevation of TSH concentrations in 10-23% of obese children, which was associated with normal or slightly elevated thyroxine and triiodothyronine values. Two studies reported ultrasonographic hypoechogenicity of the thyroid in obese children with hyperthyrotropinemia, which was not caused by autoimmune thyroiditis; therefore, the authors hypothesized a link to chronic inflammation in obesity. Weight loss led to a normalization of elevated TSH levels in two studies. The adipokine leptin is the most promising link between obesity and hyperthyrotropinemia since leptin stimulates the hypothalamic-pituitary-thyroid.
  
  
  CONCLUSIONS
  The elevated TSH levels in obesity seem a consequence rather than a cause of obesity. Therefore, treatment of hyperthyrotropinemia with thyroxine seems unnecessary in obese children.
authors: Department of Pediatric Endocrinology, Diabetes, and Nutrition Medicine, Vestische Hospital for Children and Adolescents, University of Witten/Herdecke, Datteln, Germany. T.Reinehr@kinderklinik-datteln.de
authors: Thomas
authors: T
authors: Reinehr
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D006981:Hyperthyroxinemia / Q000097:blood / Q000188:drug therapy / Q000209:etiology*; D009765:Obesity / Q000097:blood* / Q000150:complications; D011988:Receptors, Thyroid Hormone / Q000627:therapeutic use; D013961:Thyroid Gland / Q000378:metabolism*; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000627:therapeutic use; D015431:Weight Loss / Q000502:physiology
chemical_list: D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones; D013972:Thyrotropin; D013974:Thyroxine