Clinical Characteristics and Thyroid Findings in Children with Isolated Premature Adrenarche

Objectives: Premature adrenarche (PA) is associated with accelerated adrenal maturation, but data regarding thyroid characteristics in children with isolated PA are limited. We aimed to describe the clinical features of children with idiopathic PA and investigate the relationships between thyroid function, thyroid autoimmunity, and adrenal androgen secretion. Methods: This retrospective single-center study included 435 children (378 girls, 57 boys) with idiopathic PA evaluated between 2014 and 2024. Clinical, anthropometric, biochemical, and thyroid data were analyzed. Associations between adrenal and thyroid parameters were examined using correlation and group comparison analyses. Results: Girls accounted for 86.9% of the cohort. Children were generally taller than their genetic target height and frequently had excess weight. Boys exhibited higher serum dehydroepiandrosterone sulfate (DHEAS) concentrations than girls and more often met criteria for exaggerated adrenarche despite less advanced clinical androgenization. Lower birth weight (BW) was associated with higher DHEAS concentrations, and children born with low BW more frequently demonstrated exaggerated adrenarche. BW SDS showed a significant inverse correlation with DHEAS concentrations. In contrast, DHEAS concentrations were unrelated to body mass index (BMI) SDS or bone age advancement. Height SDS increased progressively with increasing BMI category in both sexes, whereas DHEAS concentrations remained comparable across weight groups. Thyroid abnormalities were identified in 8.0% of the cohort. Free thyroxine and thyroid-stimulating hormone concentrations were within the normal range in most children and showed no association with DHEAS concentrations or exaggerated adrenarche status. Although thyroid autoantibody positivity was frequent among the tested subgroup, it was not associated with adrenal androgen concentrations. Conclusions: Idiopathic PA is characterized by accelerated linear growth, frequent excess weight, and an inverse relationship between birth weight and adrenal androgen secretion. Thyroid function was not associated with adrenal androgen production within this PA cohort. The frequent thyroid autoantibody positivity observed in the selected tested subgroup should be interpreted cautiously and cannot be considered PA-specific in the absence of healthy control groups; prospective controlled studies are needed.