Endocrine Abstracts

Background: There is a great controversy on whether subclinical hypothyroidism (SH) in children should be treated for TSH values between 4.5 and 10 mU/l. In adults SH has been associated with abnormalities in lipid profile and increased risk of atherosclerosis. Data in untreated SH children are scanty.

Objective: The aim of this cross-sectional controlled study was to evaluate in children the effects of long term untreated SH on lipid profile and endothelial function.

Patients and Methods: Twenty children aged 9.7±0.6 years with long-term idiopathic SH (lasting 3.5±0.5 years), and 20 age and sex matched healthy controls underwent clinical examination and lipid profile evaluation. Endothelial function with flow-mediated dilation (FMD), an early marker of atherosclerotic event, was assessed by brachial Doppler ultrasound.

Results: No significant differences were observed between SH children and controls in BMI (0.2±0.2 vs −0.3±0.3 SDS), total cholesterol (TC; 149.6±7.4 vs 141.8±7.5 mg/dl), LDL-cholesterol (LDL-C; 85.2±5.2 vs 81.6±4.7 mg/dl), triglycerides (TG; 72.0±8.3 vs 66.0±5.1 mg/dl), atherogenic index (3.1±0.2 vs 2.8±0.1) and in mean FMD values (12.3±1.2% vs 12.9±1.1%). A significant difference was only observed in HDL-cholesterol (HDL-C) that was lower in SH children compared to controls (50.3±3.2 vs 58.0±6.8 mg/dl, P<0.0001).

Conclusions: Untreated idiopathic SH in children is not associated with significant abnormalities of lipid profile and endothelial function. However, the mild decrease in HDL-C might represent a first unfavorable change in lipid profile. Further studies on a larger number of patients with long-term follow-up are needed to clarify whether children with SH are at risk of subclinical abnormalities that may require levothyroxine treatment.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.