The effect of insufficient iodine intake on the size and function of the thyroid gland

BACKGROUND: The supply of iodine indisputably affects the function of the thyroid gland. It is not clear, however, as to what extent a moderate iodopenia affects common thyroid parameters. OBJECTIVES, STARTING POINT AND MAIN PURPOSE: The aim of the study is to evaluate the influence of iodopenia (ioduria below 50 micrograms of iodine per litre of urine) on the values of T4, T3, TSH, the ankle-jerk time and sonographically ascertained thyroid gland volume in randomly selected sample of Czech population from 4 regions. METHODS: Ioduria was assessed by means of Sandel-Kolthoff method, total thyroxine, triiodothyronine and thyreotropic hormone by immunoluminiscence method; the volume of the thyroid gland sonographically according to Gutekunst and the ankle-jerk reflex by electromagnetic record method. RESULTS: Iodopenia affects a majority of investigated parameters in dependence on age. T4 is significantly higher in iodopenic adults, T3 is significantly higher in iodopenic children, TSH is significantly higher in iodopenic adults and the ankle-jerk time is prolonged in iodopenic adults. The statistical significance of the effect of iodopenia on the volume of thyroid gland was not proved. CONCLUSION: Iodopenia of a mediate degree affects commonly used parameters of the thyroid gland function in dependence on age and other factors which are to be more precisely analyzed using a larger sample. The statistical significance of the effect of iodopenia on the volume of thyroid gland was not proved. (Tab. 1, Fig. 5, Ref. 13.).