Objective: To prospectively evaluate the course of subclinical hypothyroidism (SH) in children and adolescents with no underlying diseases and no risk factors, which might interfere with the progression of SH. Design: Clinical status, thyroid function, and autoimmunity were prospectively evaluated at entry and after 6, 12, and 24 months in 92 young patients (mean age 8.1G3.0 years) with idiopathic SH. Results: During the study, mean TSH levels showed a trend toward a progressive decrease while FT 4 levels remained unchanged. Overall, 38 patients normalized their TSH (group A): 16 patients between 6 and 12 months, and 22 patients between 12 and 24 months. Among the remaining 54 patients, the majority maintained TSH within the baseline values (group B), whereas 11 exhibited a further increase in TSH above 10 mU/l (group C). Baseline TSH and FT 4 levels were similar in the patients who normalized TSH, compared with those with persistent hyperthyrotropinemia. Even in the patients of group C, both TSH and FT 4 at entry were not different with respect to those of groups A and B. No patients showed any symptoms of hypothyroidism during follow-up and no changes in both height and body mass index were observed throughout the observation period. Conclusions: (a) The natural course of TSH values in a pediatric population with idiopathic SH is characterized by a progressive decrease over time; (b) the majority of patients (88%) normalized or maintained unchanged their TSH; and (c) TSH changes were not associated with either FT 4 values or clinical status or auxological parameters.

Mild long-lasting untreated idiopathic SH may be associated with subtle proatherogenic abnormalities. Although it is difficult to establish whether these mild abnormalities represent the early steps in the initiation of atherogenesis, these children need to be carefully monitored for metabolic complications.

Subclinical hypothyroidism is defined as serum levels of TSH above the upper limit of the reference range, in the presence of normal concentrations of total T or free T. This biochemical profile might be an indication of mild hypothyroidism, with a potential increased risk of metabolic abnormalities and cardiovascular disease recorded among adults. Whether subclinical hypothyroidism results in adverse health outcomes among children is a matter of debate and so management of this condition remains challenging. Mild forms of untreated subclinical hypothyroidism do not seem to be associated with impairments in growth, bone health or neurocognitive outcome. However, ongoing scientific investigations have highlighted the presence of subtle proatherogenic abnormalities among children with modest elevations in their TSH levels. Although current findings are insufficient to recommend levothyroxine treatment for all children with mild asymptomatic forms of subclinical hypothyroidism, they highlight the potential need for assessment of cardiovascular risk among children with this condition. Increased understanding of the early metabolic risk factors associated with subclinical hypothyroidism in childhood will help to improve the management of affected individuals.

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.

Background: There are few studies investigating the factors which may affect different biochemical presentations of Hashimoto’s thyroiditis (HT) and these are frequently based on limited pediatric populations. Aims: (1) To assess the frequency of thyroid function patterns at HT diagnosis in 608 children and adolescents, and (2) to analyze the factors that affect thyroid status at diagnosis. Results: At presentation, test results showed euthyroidism in 52.1% of patients (subgroup A), overt or subclinical hypothyroidism in 41.4%, and overt or subclinical hyperthyroidism in 6.5%. The mean age of patients with thyroid dysfunctions (subgroup B) was significantly lower than that of subgroup A, and the rate of children below 10 years of age was significantly greater in subgroup B. Other variables related to thyroid function patterns were prepubertal status; association with either Down or Turner syndromes, which correlated with increased risk of thyroid dysfunctions, and association with other autoimmune diseases, which correlated with decreased risk of thyroid dysfunctions. None of the remaining factors analyzed were associated with increased risk of thyroid dysfunctions. Conclusions: Biochemical thyroid function patterns at HT presentation in childhood and adolescence are mainly conditioned by patients’ age.