Endocrine Abstracts

Obesity and weight excess is a widespread condition all over the world, as well as thyroid nodular disease. Screening studies in different populations prove a higher frequency of nodular thyroid formations of various nature in overweight individuals.

Aim: In our study, we evaluated the dynamics of the volume of dominant and non-dominant nodular formations, as well as their sonographic structure in overweight patients with prediabetes in the groups with two-year administration of Metformin and without.

Materials and methods: We have screened 550 patients in rural areas of Belarus. Anthropometry, Endocrinologists examination, thyroid ultrasound and serum blood tests were performed. Of the screened cohort there were 183 persons with BMI over 27 kg/m² associated with thyroid nodules who agreed to participate with informed consent. All cases of thyroid malignancy, thyrotoxicosis, Hashimoto thyroiditis and severe hypothyroidism were excluded from recruitment. Initial consultation with the proposal of individual weight-loss, nutrition and physical activity program was made for all participants. Additionally, those, who had metabolic reasons, glucose intolerance, dislipidemia – were prescribed Metformin in the dose of 1000–2550 mg/day. Two groups were formed – Overweight with thyroid nodules (‘OWTN’) and Overweight with thyroid nodules and Metformin intake (‘MFI’). The groups were comparable by age, BMI, metabolic characteristics and thyroid status.

Results: As a result of 2 year follow up we have observed improvement in metabolic parameters of the MFI-group, showing improved glycaemic and lipid profiles, compared to OWTN-group. But we have detected a significant increase in number and volume of thyroid nodules in OWTN-group up to 1.84 ± 1.47 ml, comparing to 1.37 ± 0.99 ml in the MFI-group (P = 0.0399), with a non-significant weight reduction, in between groups. As for thyroid status – there was also a significant difference in TSH (3.94 ± 1.0 vs 2.89 ± 0.7, P < 0.001) and FT4 levels (16.22 ± 2.48 vs 16.98 ± 2.05, P = 0.027) accordingly.

Conclusion: The obtained results of dynamic observation indicate a significantly less active increase in the volume of nodular formations in the cases of prolonged use of Metformin. Possible mechanisms of Metformin-induced PPAR-g receptor activation and additional effects of improved insulin sensitivity as well as Metformin direct influence on TSH-receptor affinity and activity for controlling neoplastic processes and thyrocyte proliferation are discussed. Larger number cohort and prolonged observation are still desirable.