Endocrine Abstracts

JOINT364

Background: Hyperthyroidism has been linked to asthma exacerbations, while some studies suggest an increased risk of hypothyroidism in individuals with asthma. Although several studies have shown a positive association between asthma and thyroid disorders, these findings are primarily focused on adult populations. Research exploring the prevalence of thyroid dysfunction and its impact on asthma control in pediatric populations remains limited.

Objective: To determine the prevalence of thyroid dysfunction in asthmatic children aged 6 to 15 years and to assess the relationship between thyroid function and the level of asthma control in this population.

Methods: A cohort of 80 children with BA (24 girls, 56 boys; mean age 111.3 ± 25.1 months) underwent comprehensive clinical evaluation, including spirometry, the Asthma Control Questionnaire (ACQ-5), and laboratory assessments of thyroid-stimulating hormone (TSH), free thyroxine (T4), and anti-thyroperoxidase antibodies (anti-TPO) via ELISA.

Results: Elevated TSH levels, indicative of subclinical hypothyroidism (maximum 11.45 mIU/l), were observed in 22 patients (27.5%), all without hypothyroid symptoms or anti-TPO elevation. TSH levels ranged from 3.16–5.74 mIU/l in other participants, while free T4 levels were mildly elevated in 18 patients but remained within clinically insignificant limits (maximum 23.1 pmol/l). A weak negative correlation was identified between TSH levels and ACQ-5 scores (r = -0.29, P = 0.033). Subclinical hypothyroidism was most prevalent (27.5%) in patients with fully controlled BA (mean TSH 3.39 ± 1.96 mIU/l) but absent in those with uncontrolled BA (mean TSH 1.87 ± 0.73 mIU/l). Patients with partially controlled BA exhibited intermediate TSH levels (mean TSH 2.93 ± 1.5 mIU/l), suggesting potential iodine deficiency. Despite these trends, group differences in TSH were not statistically significant (F = 1.74, P = 0.1858). Free T4 levels showed no significant variation across asthma control groups but negatively correlated with FEV1 (r = -0.42, P = 0.01). Normal TSH levels in poorly controlled BA may reflect suppression by stress-induced or exogenous corticosteroids rather than optimal thyroid function.

Conclusion: Subclinical hypothyroidism is common among children with well-controlled BA, occurring in 27.5% of cases. Further studies are needed to clarify the clinical significance and mechanisms underlying this association.