TABLE1 (cont'd) PLATELETS, WOMEN 1988 1989 1990 1991 318 + 312 + 272+ 280 + 84(n=47) 68(n=45) 44(n=44) 55(n=39) 319 + 300 + 272 + 296 + 87(n=28) 71(n=28) 55(n=29) 71(n=27) 356 + 352+ 322+ 336 + 100(n=44) 83(n=47)* 58(n=46)* 79(n=46) HEMOGLOBIN, MEN 1988 1989 1990 1991 15.14 14.7+ 148+ 149+ 12 16 15 13 146+ 143+ 14.0+ 14.34 11 13 14 13 15.14 15.34 15.44 15.4+ 12 14 14 1.6 HEMOGLOBIN, WOMEN 1988 1989 1990 1991 13.44 13.4+ 13.24 13.0+ 1.0 10 1.0 1.0 13.2+ 133+ 13.14 12.8+ 1.0 0.9 11 14 129+ 13.0+ 129+ 12.84 13 13 13 12 * Significantly different (p <0.05) from the Comparison Group Hypothyroidism: Thyroid hypofunction, either clinical or biochemical, has been documented as a consequence of radiation exposure in fourteen Rongelap individuals (Larsen et al., 1982). In 1983 another exposed person was diagnosed as being biochemically hypothyroid based on results of routine thyroid function testing (Adamsetal., 1988). The patient was an asymptomatic 34-yearold man who had no abnormality on physicai examination of the thyroid. Treatment with synthroid was started in 1984. This represented the first case of spontaneous hypothyroidism diagnosed in the Utirik population. He was 1 year of age at the time of exposure, and, being from Utirik, no thyroxine suppression had been subsequently prescribed. An estimate of his total thyroid radiation dose was 561 cGy(internal = 550 cGy; external = 11 cGy). Clinical follow-up of this patient since 1987 has revealed the following. At the patient’s request thyroid function tests were repeated by physicians of the Health Services of the Marshall Islands while he presumably was not taking thyroxine. However, we do not know the assay methodology or whether the patient in fact, discontinued his thyroxine. The results were found to be normal. The conclusion of those physicians was that he was euthyroid and that the decrease in thyroid function noted by the Brookhaven medical program represented self-limited hypothyroidism due to thyroiditis. However, there was no evidence of a preceding hyperthyroid state. Furthermore, his thyroid function studies over the years were: Thyroxine TSH* 1973 1977 1979 1980 1981 1983 1984 1985 1986 1987 1988 1989 48 3.7 6.3 4.7 4.7 5.8 Thyroxine 1990 1991 *Normal ranges: 3.7 0.6 3.7 73 5.4 3.8 11.4 3.3 75 4.2 2.1 TSH* 6.2 3.3 3.0 42 Total thyroxine - 4.5-12.5 ug/ml; Thyroid stimulating hormone (TSH)- 0.43- 3.8 ulU/ml. 1i