Thyroid Function Patterns at Hashimoto's Thyroiditis Presentation in Childhood and Adolescence Are Mainly Conditioned by Patients' Age.

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.