Physiological doses of iodine and carriage of antibodies thyroid peroxidase: an open, randomized trial

Abstract

This prospective open randomized study explored the effects of the physiological doses of iodine on the structure and function of the thyroid in persons who were carriers of thyroid peroxidase antibodies (TPOAb). The study included 44 females with normal thyroid function and levels of TPOAb of more than 100 mU/l. By employing open block randomization using a random number tables, the patients were divided into 2 groups: 1) 22 females who received potassium iodide in a daily dose of 100 pg for 6 months (a study group) and 2) 22 patients who did not take any therapy or placebo throughout the study (a control group). Three patients (they all from the study group) were excluded from the study due to their incompliance. Following 6 months, two patients were diagnosed as having primary hypothyroidism : 1 patient from the study group had subclinical hypothyroidism with an increase in the level of TSH up to 7.2 mU/l; the other patient from the control group had obvious hypothyroidism (TSH, 67 mU/l). Evaluation of the time course of changes in the level of TSH and the volume of the thyroid revealed no difference between the study and control groups throughout and by the end of the study. A statistically significant decrease in the volume of the thyroid was found in a group of patients with the initially enlarged thyroid treated with potassium iodide. It is concluded that the physiological doses of iodine do not produce any substantial effect on the function and volume of the thyroid in ATOAb carriers.