62 FALLOUT EFFECTS—-MARSHALL [ISLANDERS had surgery for removai of thyroid nodules. More recently a numberof surviving adults, who received considerably less exposure, without detectable thyroid ab- normalities, have shown modest increases in TSH levels. Since many in this group were over 50 years of age, tests of thyroid function were done in older unexposed people, and the results indicated that this finding was not due to age alone (37). Thyroid Nodules In 1964 benign thyroid nodules were removed from three teenage Rongelap girls in the exposed group. Since then benign and malignant nodules have devel- oped in the exposed Rongelap and Ailingnae groups, and more recently to a lesser extent in the exposed Utirik group. A number of such nodules have been noted in the unexposed comparison populations. Table 3 summarizes these findings. The six children exposed at 1 year of age, who had the highest doses, are compared with other children less than 10 years old and with people more than 10 years old at exposure. A total of 46 exposed Marshallese (29 in the Rongelap-Ailingnae group and _17 in the Utink group) have developed thyroid nodules, and 42 of these have had them removed. Of 600 people in the age-matched unexposed population, 35 had nodules and 14 have had surgery. Table 3 showsthe greater development of thyroid nodules in the higher-dose Rongelap-Ailingnae group than in the lower-dose Utirik or matched control group. The greater prevalence in the younger members of the Rongelap group with the larger doses is in contrast to TABLE 3. Thyroid nodules (1981) Group age 1954 Rongelap 1 yr 2-10 <10 = 10 Utirik <10 = 10 Matched controls <10 = 10 6 2 1,500(7) 16 210 Ailingnae No. Est. thyroid dose(rads) 45 . 800-1500 387 Total nodules —_-—-—— No. % Carcinoma —_ No. % 4 66.7 0 0 6 13.3 3 6.6 13 81.2 1 6.2 7 t2 275-450 140 2 4 28.6 33.3 0 0 0 0 64 100 60-90 53 5 12 7.8 12.0 1 2 1.6 2.0 6 29 2.6 7.8 2 3 0.9 0.8 229 371 wt he t‘rage+ 3h | Dhol 2 Prevalence has not been corrected for control leveis. The carcinoma prevalenceis probably low, since all unoperated nodule cases were considered benign forthis table. Occult carcinomas were not included as carcinomas.