Endocrine Abstracts

Introduction: The adipose tissue secrets visfatin, that might have metabolic effect. Changes of visfatin serum concentrations have been observed in different thyroid pathologies. Thyroid hormones affect metabolism, thus, both hypo- and hyperthyroidism might significantly alter body composition.

Aims of the study: We aimed to investigate the effect of restoration of euthyroidism on serum visfatin in severe thyroid dysfunction, and its associations with insulin resistance and body composition. To limit the interference of individual factors, we have also analysed changes in three different thyrometabolic states in the same patients.

Patients and methods: The study was designed as an observational with consecutive enrollment. Newly diagnosed females with overt hypo- or hyperthyroidism caused by autoimmune thyroid diseases (Hashimoto’s disease or Graves’ disease, respectively) were included into the study. Laboratory parameters and body composition were assessed in each patient at the diagnosis and after restoration of thyroid function.

Results: Initially, 105 females were enrolled into the study: 49 hyperthyroid females (median age of 34 years) and 44 hypothyroid females (median age of 46) completed the study. In the hyperthyroid group, visfatin levels increased (<0.0001), while glucose levels decreased (<0.0001) after restoration of euthyroidism. Total body mass and fat mass in the trunk and limbs significantly increased during the treatment. In the hypothyroid group, significant weight loss after treatment resulted from decrease of fat and muscle masses in trunk and limbs. For pooled data of all women and all measurements, weak positive correlation between TSH concentrations and total body weight, as well as fat mass (r=0.19, P=0.01; r=0.2, P=0.006, respectively). There was also inverse correlation between FT4 and FT3 and total body weight (r=−0.246, P=0.0008; r=−0.17, P=0.022, respectively) and fat mass (r=−0.16, P=0.026; r=−0.18, P=0.018, respectively). Visfatin serum concentrations positively correlated with total fat mass (r=0.19, P=0.01) and insulin levels (r=0.17, P=0.018).

Conclusions: We may conclude that restoration of thyroid function is not associated with beneficial changes in body composition, especially among hyperthyroid females, reflected by the significant increase of fat mass followed by the increase of circulating visfatin concentrations.