Subclinical Hypothyroidism in Children: Natural History, Risk Factors, and Outcomes

Area of Science:

• Pediatric Endocrinology
• Thyroidology
• Clinical Pediatrics

Background:

• Subclinical hypothyroidism (SH) in children is defined by elevated thyroid-stimulating hormone (TSH) with normal thyroid hormones, often asymptomatic.
• Predictors of SH progression and treatment needs in pediatric populations remain unclear.

Purpose of the Study:

• To evaluate the natural history of mild pediatric SH.
• To identify clinical factors associated with elevated TSH.
• To determine predictors of progression to levothyroxine treatment and assess growth outcomes.

Main Methods:

• Retrospective review of 111 children (3 months-18 years) with mild SH (TSH 5-10 mIU/L).
• Analysis of demographic, biochemical, anthropometric, etiological, and imaging data.
• Categorization into idiopathic or associated clinical factors (autoimmune thyroiditis, iodine imbalance, obesity, medication use).

Main Results:

• 40.5% of children normalized TSH, 44.2% remained with SH, and 15.3% required levothyroxine treatment.
• Idiopathic SH showed a favorable course (8.6% required treatment).
• Hashimoto's thyroiditis (HT) and baseline TSH > 7.5 mIU/L were significant predictors of progression.

Conclusions:

• Mild pediatric SH is generally benign and self-limiting, especially in idiopathic cases.
• HT and higher baseline TSH levels are key predictors of progression.
• Growth parameters remain stable, supporting individualized management based on TSH severity and autoimmune status.