Recent studies have shown that patients with high levels of insulin seen in obesity, diabetes, and in thin patients with insulin resistance have a larger thyroid gland by volume studies by ultrasound, and have a significant increased number of nodules.Thyroid vol.18(4),461-164 2008.
Obese and non-obese patients with insulin resistance had increased thyroid volumes, compared to obese, and normal patients without elevated insulin levels.
Also, the number of nodules was increased over controls without excess insulin. Well, if increased insulin is a thyroid growth factor as seen in animals studies, and suggested by these data, maybe we need to consider another medical approach to nodule therapy.
Well, the thyroid group from Argentina has treated patients with the drug metformin to reduce the insulin levels in patients with thyroid nodules. Metformin alone, with T4, T4 alone, and control with no therapy for 6 months.
TSH was kept at 0.1-0.9 range,in the treated groups. The metformin dose was 1 gram. The patients were all from an iodine deficient country. The dramatic results were a marked reduction in the nodules with metformin alone, 73%, but this was even better with the addition on T4, 95%.
The control without therapy was 26% reduction, and the T4 only was 35%. T4 only just prevented increased growth, but did not decrease nodule volume compared to controls. Insulin and TSH are growth factors for thyroid nodules.
The dramatic results in Argentina is partially due to iodine deficiency, and the effects should be less in the USA. However, combination therapy may be worth a try in diabetic, obese patients, or thin patients with proven high insulin levels seen during a 75 gram glucose load test, who have benign thyroid nodules by Ultrasound Guided FNA.
6 th World Congress on Insulin Resistance Syndrome
September 25-27 2008
Los Angeles Ca
Metformin Treatment of Benign Thyroid nodules in Euthyroid Patients with Insulin Resistance
H. Niepomniszcze et al.