Practice Uncertainties

Should we treat subclinical hypothyroidism in obese children?

BMJ 2016; 352 doi: https://doi.org/10.1136/bmj.i941 (Published 16 March 2016) Cite this as: BMJ 2016;352:i941
  1. Usha Niranjan, specialist registrar in paediatrics1,
  2. Neil P Wright, consultant paediatric endocrinologist1
  1. 1Department of Paediatric Endocrinology and Diabetes, Sheffield Children’s Hospital NHS Trust, Sheffield S10 2TD, UK
  1. Correspondence to: U Niranjan usha.niranjan{at}nhs.net
  • Accepted 23 December 2015

What you need to know

  • Hyperthyrotropinaemia comprises an isolated raised thyrotropin (>4.5 mIU/L but <10 mIU/L) without clinical symptoms, thyroid antibodies, goitre, or associated thyroidal illness

  • It is common in obese children but seems to be a consequence rather than the cause of obesity and may normalise after weight loss

  • Offer lifestyle measures to promote weight loss because there is no evidence to justify thyroxine treatment for subclinical hypothyroidism with obesity. However monitor thyrotropin and free thyroxine every 6-12 months in view of the unlikely but possible progression to overt hypothyroidism

Thyroid function tests are often requested when investigating obese or overweight children. Slightly raised thyrotropin (TSH) with normal free thyroxine—subclinical hypothyroidism (hyperthyrotropinaemia)—is a common finding. An isolated raised thyrotropin is best described as hyperthyrotropinaemia rather than subclinical hypothyroidism and by definition excludes people with clinical symptoms, positive thyroid antibodies, goitre, or associated thyroidal illness.1 2 The adult consensus guideline defines it as a thyrotropin value between the upper limit of the local normal range and 10 mIU/L.1 Paediatric reviews have adopted a similar definition and thresholds.3 Reference ranges vary with the laboratory but are typically 0.45-4.5 mIU/L.1 In paediatric practice, as in adults, thyrotropin >10 mIU/L is potentially indicative of overt hypothyroidism.4

An isolated increase in thyrotropin is more common in overweight children, with a reported prevalence of 7-23% in obese children compared with only 2% in normal weight children.4 5 Thus it is unclear whether raised thyrotropin is a cause or consequence of obesity and whether thyroxine should be used to help manage these children’s weight.

What is the evidence of the uncertainty?

To ascertain the association between obesity and hyperthyrotropinaemia in children, we searched the Medline, Embase, and Cochrane databases until February 2015 …

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