Endemic Goiter in Greece: An Iodine Balance Study in the Field

Abstract

Iodine balance studies were carried out in the homes of 15 goitrous and 15 nongoitrous females in a Greek village with endemic goiter, and radioiodine techniques were used to evaluate iodine metabolism in the same subjects. The mean ±se dietary iodine intake of the goitrous (21.2 ±2.2 μg/day) was not significantly different from the nongoitrous (30.6 ±8.5), whereas the urinary iodine excretion was significantly reduced in the former group. The fecal iodine excretion was 5.1 ±0.16 and 6.4 ±0.39 μg/day in the goitrous and the nongoitrous, respectively. This latter group was apparently in a negative iodine balance. Quantitative studies of iodine metabolism revealed that, although the plasma inorganic iodine level was low in both groups studied, the greatly increased radioiodine uptake resulted in a significantly higher absolute iodine uptake in the goitrous. However, in spite of greater iodide trapping, the trend for slightly lower PBI and BEI values could be taken as indirect evidence against an increased thyroid hormone secretion rate in the goitrous. There was not a significant difference in the calculated amount of endogenous iodide derived from the deiodination of thyroid hormones. It is concluded that the difference in gland size between goitrous and nongoitrous persons from the same iodinedeficient area is probably due to the interplay of several factors, including perhaps a greater degree of iodine deficiency and a reduced thyroidal biosynthetic capacity in the goitrous.