-19- ‘In view of the seriousness of these findings it was decided to initiate thyroid hormone therapy on the exposed people. The rational for this form of therapy was that by furnishing normal levels of exogenous thyroid hormone, pituitary TSH levels would be repressed and remove the thyroid gland from stimulation of that hormone. It is thus hoped that further development of nodules and possible malignancy might be prevented and, of equal importance, enhancement of growth and development in the children might result. Conclusive results of this treatment must await further observations and a stricter treatment regimen. However it does appear that several nodules have reduced on this treatment and some children may be showing increased growth. Figure 26 shows the results of hormone treatment on the 2 boys who had shown growth retardation, referred to before and shown in Figure 21. It can be seen that there has been a tendency to an increase in skeletal development coincident with the institution of the thyroid therapy. The exclusive development of these thyroid abnormalities in the irradiated Marshallese children seems clearly to indicate the radiation etiology. The development of such abnormalities is consistent with the known etiological relationship of irradiation of the thyroid gland and the development of such lesions(Doniach, Kneeland et al.; Lindsay et al.; Goldberg and Chaikoff; Potter et al.). The high incidence in the children is probably related to the larger dose of radiation received by their smaller glands. Though the pathological changes in the nodules are similar to those seen in iodine deficiency goiter there is no reason to suspect such causal relationship in the Marshallese cases since dietary iodine is normal, urinary excretion of iodine is in the normal range and there are no known goitrogenic foods. 5001310