Linear growth and intellectual outcome in children with long-term idiopathic subclinical hypothyroidism

Abstract

Objective: The treatment of children with subclinical hypothyroidism (SH) is controversial for TSH values between 4.5 and 10 mU/l. The aim of this cross-sectional, controlled study was to evaluate growth and intellectual outcome in children with persistent SH who have never been treated with levothyroxine. Design and methods: Clinical and auxological parameters, thyroid function, and intellectual outcome were evaluated in 36 children with persistent SH at the age of 9.7G0.6 (range 4-18.0) years. Children had been followed longitudinally for 3.3G0.3 (range 2.0-9.3) years, from first diagnosis of SH until enrollment in the study. Thirty-six age-and sex-matched children were enrolled in the study as controls. Results: At study entry, height (K0.8G0.2 SDS), bone age/chronological age (BA/CA ratio 0.92 G0.6), and body mass index (BMI K0.1G0.2 SDS) in SH children were normal. Despite long-term duration of SH, none of these parameters showed a worsening with respect to height (K0.7G0.2 SDS), BA/CA (0.97G0.03), and BMI (K0.1G0.2) at the time of first SH detection. None of the children showed overt signs or symptoms of hypothyroidism during the follow-up. Verbal (99.1G2.2), performance (100.4G1.9), and full-scale (99.7G1.9) intelligence quotient (IQ) scores in SH children were normal and comparable to those of controls. No relationship was detected between IQ scores and the degree or duration of SH. Conclusions: Persistent SH in children is not associated with alterations in growth, bone maturation, BMI, and cognitive function or other complaints that could be ascribed to SH even after several years without therapeutic intervention.

ENDOCRINE DISORDERS IN CHILDHOOD AND ADOLESCENCE: Natural history of subclinical hypothyroidism in children and adolescents and potential effects of replacement therapy: a review

“…In accordance with these data, a recent Italian study analyzing growth and intellectual parameters in a cohort of 36 children with persistent idiopathic SH followed longitudinally for a period of 2.0-9.3 years demonstrated no alterations in growth, bone maturation, BMI status, and cognitive functions in presence of persistently elevated TSH values (37). Therefore, thyroid hormones involved in growth and neurocognitive development seem to work properly, regardless of the persistently elevated TSH, in the absence of replacement therapy.…”

Five-year prospective evaluation of thyroid function in girls with subclinical mild hypothyroidism of different etiology

“…In the children with HT-related mild SH, it has been just recently reported that the evolution of thyroid function tests seems to be frequently characterized by a deterioration over time, whereas such risk is very low in the children with idiopathic SH (12). However, the available prospective studies on the natural history and prognosis of SH in children are very few and based on 2-3 years follow-up investigations (12,13,14,15,16), which hampers the ability of drawing firm conclusions about the relevance of those findings.…”

Growth in Children with Thyroid Dysfunction

“…In adults, SCH has been associated with several complications, such as progression into overt hypothyroidism, abnormalities of lipid profile, increased risk of atherosclerosis and cardiovascular morbidity and clinical signs and symptoms of mild disease, including impaired cognitive function (Cerbone et al, 2011). Treatment is currently recommended in SCH subjects with a TSH value above 10 mU/l, whereas treatment for TSH levels between 4.5 and 10 mU/l remains a matter of debate (Wiersinga et al, 2012).…”