Endocrine Abstracts

Background: Thyroid function regulates a wide array of metabolic parameters and significantly affects lipoprotein metabolism. Subclinical hypothyroidism (SCH) is the most common thyroid disorder, with a prevalence up to 10% in adult populations. Subclinical hypothyroidism is defined as mild elevation in thyroid stimulating hormones (TSH) in presence of normal free thyroxine (fT4) and free triiodothyronine (fT3). This mild elevation of serum TSH is caused by a minor initial decrease in thyroidal secretion of thyroxine (T4) which activates piruitary-thyroid axis. The reason for maintaining T4 values within the reference range is the exquisite sensitivity of the pituitary thyrotroph for even very small decreases of serum T4.

Objectives: The aim of this study was to compare metabolic profile in patients with SCH and healthy controls.

Methods: The study group consisted of 75 patients with SCH (group 1, TSH 4.6–24.49 mIU/L) and 47 healthy controls (group 2, TSH 0.4–4.2 mIU/L) who were matched by age and weight. We compared glucose, HbA1c, HOMA index, cholesterol, HDL, LDL and trigyceride levels between groups. The data were analyzed by Welch Two Sample T-test with 95 percent confidence interval.

Results: There were no statisticaly significant difference in glucose levels, as well as in HbA1c and HOMA index between groups (glucose 5.249 vs 5.198 mmol/l; P=0.725; HbA1c: 5.55% vs 5.42%; P=0.126; HOMA 2.51 vs 2.48; P=0.959). Also, there were no statisticaly significant difference in cholesterol levels, HDL, LDL and trigyceride levels between groups (cholesterol 5.527 vs 5.563 mmol/l; P=0.872; HDL 1.522 vs 1.579 mmol/l; P=0.411; LDL 3.407 vs 3.414 mmol/l; P=0.968; Tg 1.317 vs 1.194 mmol/l; P=0.34).

Conclusions: These data suggest that activation of pituitary-thyroid axis and increase of TSH levels does not affect metabolic profile in patients with subclinical hypothyroidism.