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

Area of Science:

• Pediatric Endocrinology
• Child Development
• Thyroid Disorders

Background:

• Treatment for subclinical hypothyroidism (SH) in children with TSH levels between 4.5 and 10 mU/l remains controversial.
• Understanding the long-term effects of untreated SH is crucial for clinical decision-making.

Purpose of the Study:

• To evaluate growth and intellectual outcomes in children with persistent subclinical hypothyroidism who have never received levothyroxine treatment.
• To assess if untreated SH impacts auxological parameters, bone maturation, and cognitive function.

Main Methods:

• A cross-sectional, controlled study involving 36 children with persistent SH (age 9.7±0.6 years) and 36 age- and sex-matched controls.
• Longitudinal follow-up of SH children for 3.3±0.3 years, evaluating clinical, auxological, thyroid function, and intellectual outcomes.
• Assessment of height, bone age/chronological age ratio, body mass index (BMI), and intelligence quotient (IQ) scores.

Main Results:

• Children with persistent SH exhibited normal height, bone age, and BMI at study entry and throughout follow-up.
• No significant worsening of growth parameters or overt hypothyroid symptoms were observed during the follow-up period.
• Verbal, performance, and full-scale IQ scores in SH children were normal and comparable to controls, with no correlation to SH severity or duration.

Conclusions:

• Persistent subclinical hypothyroidism in children is not associated with adverse effects on growth, bone maturation, or BMI.
• Cognitive function and overall well-being in children with untreated persistent SH remain unaffected, even after several years.
• These findings suggest that therapeutic intervention may not be necessary for all children with persistent SH within the studied TSH range.