ESPE Abstracts

Introduction: Subclinical hypothyroidism is a form of thyroid dysfunction in which TSH level is high while serum free thyroxin (fT₄) and free triiodothyronine (fT₃) are within normal reference range. In this study, it was aimed to investigate effects of subclinical hypothyroidism on anthropometric characteristics, blood pressure, glucose and lipid metabolism by evaluating course of subclinical hypothyroidism during follow-up without treatment.

Methods: The study included patients aged 3–18 years with BMI<85th percentile and negative thyroid auto-antibodies (anti-TPO and anti-Tg) who were diagnosed as subclinical hypothyroidism. These patients were assessed at time of diagnosis, on month 3 and at year 1 during follow-up.

Results: Mean age was 9.65±2.89 years (range: 4.5–16.24) in 25 cases with subclinical hypothyroidism. At time of diagnosis, 22 cases with subclinical hypothyroidism were asymptomatic. These patients were observed without treatment. Thyroid auto-antibodies were negative at time of diagnosis and year one in all patients. The mean TSH level was 6.92±0.92 μIU/ml in the diagnosis, 4.77±1.57 μIU/ml in the third month and 4.51±1.79 μIU/ml in the first year of follow-up. 73.7% of subclinical hypothyroidism was recovered. There was no significant difference among fT₄ levels obtained at time of diagnosis, on month 3 and at year one. While there was no significant difference between fT₃ levels obtained at time of diagnosis and on month 3, fT₃ levels at year one were significantly lower than those obtained at time of diagnosis (P=0.014) but were comparable to those obtained on month 3. There was no statistical significant difference between heart rate, diastolic blood pressure, lipid profile, fasting blood glucose, fasting insulin level, HOMA-IR, hemoglobin, white blood cell, platelet, CRP levels and thyroid volume in diagnosis and in the first year of follow-up. In the first year of follow-up, systolic blood pressure and high sensitive CRP value were significantly higher than the diagnosis. However, it was seen that these values were similar in the ongoing group with subclinical hypothyroidism.

Conclusion: We observed that subclinical hypothyroidism was recovered in 68.2% on month 3 and 73.7% of children at year one among patients with non-otoimmune subclinical hypothyroidism, normal BMI and TSH level of 5.5–10 μIU/ml. We concluded that there was no progression to overt hypothyroidism during one-year follow-up and that subclinical hypothyroidism had no effect on height SDS, BMI SDS, blood pressure, glucose and lipid metabolism during follow-up without treatment in this group of patients.