that the iodoprotein levels, which, as pointed out, in the Marshallese people results in higher than expected PBI levels which masked the true hormone level. However more accurate thyroxine levels during the past several years revealed that the 2 bovs showing the greatest zrowth retardation developed marked hypothvroicisnm,.palpcole atroguy of the thyroid gland, development of coarse faciai features, dry sxin aad Sluggish Archilles reflex action and bone dysgenesis. High pituitary TSH levels in these two individuals indicated primary hypothvroidism. fore recently several other chiidren with icsser cegrees of retardation of growth had begun to show some degree of thyroid deficiency prior to surgery. This was based on lowered thyroxine levels, increased levels of TSH, reduced uptake of radioiodine and pocr response to TSH stimulation. In view of the seriousness of the above findings it was decided several years ago to give thyroid hormone therapy to the exposed people. The rationale for this therapy was to turnish normal levels of exogenous thyroid hormone thereby repressing pituitary TSH levels .and removing the gland from stimulation of that hormone. Effectiveness of treatment in regard to inhibition of growth of nodules is difficule to evaluate in view of uncertainty of adherence to a strict treatment regimen in some of the people. However the effect on growth and development of the bedy appears to be encouraging. Tne two-boys who had showed hypo- thyroidism and the greatest growth retardation showed definite enhancement. Fig. $ shows the results of hormone treatment in these two boys on develonment as evaulated by skeletal age. Fig. 6 shows the increased growth and improved appearance of one of these boys following hormone treatment. DISCUSSION As a result of the expcsure of the Marshallese people to radioactive fallout 15 years ago the only late findings of significance have been the development of thyroid abnormalities with resulcing retardation of groeth and development in the more heavily exposed children. The lack of development of nodules in th2 unexposed and lesser exposed populations in the same age range clearly .ndicates the etiological relationship of the lesions to radiation. The higher incidence of nodules in the children than in adults is probably related to the larger dose of radiation re- ceived by their smaller glarcs. The nigh incidence of these lesions in this population is perhaps a little surprising in view of the consideration of the dose and dose rate from radioiodine exposure in a fallout situation. -5,6] ‘The face that a large part of the dose was from short-lived radio- Cy iodine-> with fast dose rate may have been important. The development of these thyroid abnormalities is consistent with reports in the lictcrature on many animal studies and some human studies.°7,8: Sheline etal. (9) have reported the development of nodules in fsliow-up studies of children for hyperthyroidism with radioiodine and more recently Pincus et al. [ 10} have reported a high incidence of nodules in children who had been treated with x-radiation of the seck in infancy. (i (5 ‘ b o ; fae rol a