57 red dose people. In the Rongelap-Ailingnae group, 65% of those exposed as children had nodules compared with 27% of those exposed as adults. Paradoxically, in the Utirik population a greater percentage of adults had nodules in spite of a higher dose to the children’s glands. During the past ten years, a disturbing finding has been the further development of thyroid hypofunction, even in some Rongelap people without other detectable abnormalities. Table 3 shows the present status of thyroid hypofunction. The positive category represents individuals who have exhibited two TSH (thyroid-stimulating hormone) levels of 6 2U/mi or greater. The suggestive category represents individuals who have two TSH levels of 4 to 64. The association of radiation exposure with the developmentof thyroid abnormalities in the Rongelap population seems apparent though the Utink findings are less clear-cut. The development of thyroid tumors following radiation exposure is well documented in the Japanese exposed to the atomic bomb and in patients, particularly children, following radiation therapy. On a risk per rad basis, the induction of thyroid nodules and cancer tn the Marshallese appears to be about equal to that following X-ray exposure. Since ''I is believed to be only about one-tenth as effective as X irradiation in producing thyroid abnormalities, it seems likely that in the Marshallese the exposure to the short-lived tsotopes of iodine '"1, 337 and '51, which have more energetic betas and deliver a faster dose rate than ''I, might account for the high incidence. The findings in the Marshallese emphasize the importance of thyroid exposure to radioiodines that may result from warfare or accidents in sed DUP sed which radioiodines are released. Exposure to penetrating gammas or neutrons is a more serious hazard not only because of their acute effects. but also because of the fatal nature of malignancies such as leukemia which may develop. Deaths due to thyroid abnormalities including cancer Table 3. Thyroid Hypofunction in Marshallese Populations Group Positive a) Rongclap + Ailingnae (135-1140 rads) 15%. (13/86) 9.37 (8/86) 24.47 (21/86) 38) Utirik (30-95 rads) 0.8% (1/158) 3.8% (6/158) 4.4% (7/458) Unexposed 0.69% 1.5% 3.0% (1/1585) (1/67) (2/67) = 7) Suggestive Total? “Some ofthese subjects appear also in the nodule table, ie. they have both hypolfunction and nodutarity. .