Metformin inhibits goitrogenous effects of type 2 diabetes

Abstract

Objective: Data on the association between type 2 diabetes mellitus (T2DM) and thyroid volume are sparse. An experimental study demonstrated an inhibitory effect of metformin on the growth of human thyroid cells. So far no study on humans has investigated potentially modulating effects of metformin on the association between T2DM and thyroid volume. Therefore, we investigated these effects in a population-based cohort study. Design and methods: We used data from the Study of Health in Pomerania and included 2570 individuals for cross-sectional and 1088 individuals for longitudinal analyses. T2DM was defined by physician-diagnosed self-report or intake of antidiabetic medication. Results: In the cross-sectional data, females with T2DM treated with antidiabetic medication other than metformin had a larger thyroid volume (bZ4.69; 95% CI 1.87 to 7.50) and a higher odds ratio (OR) for goiter (ORZ1.71; 95% CI 1.05 to 2.79) than females without T2DM, whereas in males, no such association was detected. In females or males treated with metformin, T2DM was not associated with thyroid volume or goiter. In longitudinal analyses, incident T2DM not treated with metformin was significantly associated with a higher risk for incident goiter in the total population (incidence rate ratio (IRR)Z1.70; 95% CI 1.10 to 2.91). Individuals with T2DM having changed from metformin to other antidiabetic agents during follow-up also had a higher risk for incident goiter than individuals without T2DM (IRRZ2.71; 95% CI 1.74 to 4.20). Conclusions: We demonstrate an inhibitory effect of metformin on prevalent and incident goiter. Antigoitrogenous effects of metformin add to the general benefits of metformin treatment of T2DM.European Journal of Endocrinology 169 9-15

Type 2 diabetes mellitus and hypothyroidism: the possible influence of metformin therapy

“…A possible effect of metformin therapy in lowering serum thyroid‐stimulating hormone concentrations in people with diabetes and primary hypothyroidism has been suggested and this may be supported by recent evidence that metformin inhibits goitre formation in people with Type 2 diabetes . While the association between metformin usage and a lower prevalence of hypothyroidism does not necessarily imply a ‘protective’ effect of metformin therapy, the results of the present simple survey raise this possibility.…”

Metformin and thyroid disease

“…Prospective and retrospective studies showed that patients with prediabetes and type 2 diabetes mellitus (T 2 DM) had a significantly increased thyroid volume and a higher prevalence of incident goiter and nodules. Furthermore, diabetic patients treated with metformin had a smaller thyroid volume and a lower risk for the formation of thyroid nodules when compared with controls (Anil et al 2013, Ittermann et al 2013, Blanc et al 2015. These results suggested that metformin exerts an anti-proliferative activity, providing a rationale for an innovative therapy of thyroid proliferative diseases with metformin.…”

“…Patients with IR have larger thyroid volumes and higher risk for formation of thyroid nodules, and higher circulating levels of insulin are thought to increase thyroid proliferation and formation of thyroid nodules (Ittermann et al 2013, Ogbera et al 2012. One study hereof worth mentioning showed that development of thyroid nodule may depend on IR: in patients with small benign thyroid nodules and IR, metformin therapy was accompanied by a reduction in the nodular size, which was paralleled by a fall in TSH (Rezzonico et al 2011).…”

Insulinooporność w chorobach endokrynnych — sposoby terapii

“…In the population of patients with insulin resistance, metformin therapy resulted in a reduction in volume of thyroid and nodules [48]. In addition, Ittermann et al showed that type 2 diabetes patients treated with metformin have a lower thyroid volume compared to those treated with other hypoglycaemic agents [49]. Metformin also reduces the level of serum TSH, the main growth factor for thyroid cells [50].…”

“…Ponadto, Ittermann i wsp. wykazali, że pacjenci z cukrzycą typu 2 leczeni metforminą mają mniejszą objętość tarczycy w porównaniu z leczonymi innymi lekami hipoglikemizującymi [49]. Metformina również poprzez działanie ośrodkowe zmniejsza stężenie TSH w surowicy krwi, głównego czynnika wzrostowego komórek tarczycy [50].…”