Effect of levo-thyroxine treatment on weight and body mass index in children with acquired hypothyroidism

J Pediatr. 2008 Jan;152(1):96-100. doi: 10.1016/j.jpeds.2007.06.006. Epub 2007 Oct 24.


Objective: To determine whether normalization of thyroid-stimulating hormone (TSH) in children with acquired hypothyroidism is associated with a decrease in weight or body mass index (BMI).

Study design: We retrospectively identified 68 subjects with acquired hypothyroidism who were seen at least once in our center in follow-up between 1995 and 2006.

Results: Treatment with levo-thyroxine decreased the mean TSH level from 147 microU/mL initially to 5.0 microU/mL at the second visit 4.4 months later. This was not associated with a significant change in weight or BMI. Of the 68 subjects, 31% lost weight by the second visit (mean 2.3 kg). The mean initial TSH level of this group was 349 microU/mL. Thirty of the 68 children had at least 2 years of follow-up, and 19/68 had at least 4 years of follow-up. Over those intervals, weight and BMI percentiles and z scores did not change significantly from baseline values.

Conclusions: Most children treated for acquired hypothyroidism exhibited little short-term or long-term change in weight or BMI despite near-normalization of TSH. Those children who lost weight tended to have severe hypothyroidism and to have only a small weight loss. Consequently, practitioners should not expect significant decreases in weight after treatment in most children with hypothyroidism.

MeSH terms

  • Adolescent
  • Body Mass Index*
  • Body Weight / drug effects*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Hypothyroidism / blood
  • Hypothyroidism / drug therapy*
  • Hypothyroidism / etiology
  • Hypothyroidism / physiopathology
  • Male
  • Obesity / blood
  • Overweight / blood
  • Retrospective Studies
  • Thyrotropin / blood*
  • Thyroxine / therapeutic use*
  • Weight Loss*


  • Thyrotropin
  • Thyroxine