Height improvement by L-thyroxine treatment in subclinical hypothyroidism

Subclinical hypothyroidism(SH) is most commonly an early stage of hypothyroidism. Although the condition may resolve or remain unchanged, within a few years in some patients overt hypothyroidism develops, with low free T4 levels as well as a raised thyroid stimulating hormone (TSH) level. Patients with SH may have subtle hypothyroid symptoms with mild abnormalities of serum lipoproteins and cardiac functions. L-thyroxine in a dosage that maintains serum TSH levels within the normal range is the preferred therapy in these patients. Although short stature is a well-known clinical sign of overt hypo-thyroidism,the effect of SH in growth is not well established. The aim of the present study is to show the effect of treatment on height in these patients.

In the present study, 2067 patients who were admitted to the Endocrinology Department of SSK Ankara Children's Hospital, Ankara, Turkey, with the complaint of short stature were evaluated and 39 were diagnosed with SH by thyrotropin releasing hormone stimulation test. The anthropometric data of the patients who were subdivided into two groups (prepubertal and pubertal) were analyzed before and after 6-12 months of L-thyroxine treatment. Growth velocity (GV) and GV standard deviation score(GVSDS) of the groups before and after the treatment were statistically analyzed.

Both groups showed significant increases in GV and GVSDS by L-thyroxine treatment.

Patients with short stature have to be evaluated for SH in addition to other potential causes. L-thyroxine treatment in these patients provides significant improvement in height.