45 the radioiodine absorption from thefallout was not fully appreciated at the time of the early examinations. In addition to 131], the isotopes 1551, 132T and 135] contributedsignificantly to the thyroid dose. On the basis of radiochemical urine analyses several weeks after exposure it wasestimated that the adult thyroid received about 160 rads from radioiodines plus 175 rads gamma. The smaller glands of the young children, however,received an estimated 700 to 1400 rads plus 175 rads , gamma.}1 LATE EFFECTS General Health Except for growth retardation in some children and somethyroid abnormalities reviewed below, the general health of the exposed people has been good and aboutthe sameas thatof the unexposed (Table 7). Genetic effects have not been specifi- cally studied because of the small number of people involved. However, no apparent radiation- induced genetic changes have been found on routine physical examinationsin thefirst-generation children of exposed parents, with the possible exception of suggestive evidence of increased miscarriages andstillbirths among the exposed women. Malignancies Six cases of cancer have developed in the exposed group,all in females, 3 of the genital tract that resulted in death and 3 of the thyroid gland. Because the thyroid gland received a larger dose, the malignancies of that gland cannot be compareddirectly with the others. Therefore the genital cancers in the females are less positively related to radiation exposure. Leukemia surveys, including physical findings, studies of leukocyte counts and morphology, alkaline phosphatase staining, encounteredin these people was about the same in both groups. and basophil counts of 4000 white cells, showed no evidence of leukemia or leukemic tendency in any of the exposed people over the 15-year period. Mortolity Degenerative Diseases During the 15 years there have been 16 deaths in the exposed group (Rongelap + Ailingnae). the general results of physical examination, have population. The incidence of the diseases usually This represents 13.0 deaths per 1000 per annum compared with 8.3 for the Marshall Islands as a whole (1960). None of these deaths could be at- tributed directly to radiation exposure. The higher mortality in the exposed group mustbe interpreted with caution since the numbers of people involved are too small for a sensitive statistical test and there were moreolder people in the exposed group. Cardiovascular andarthritis surveys, as well as not shown any apparentincreased incidence of degenerative disease in the exposed people. The Marshallese people appear to have less hypertension on the whole thanis noted in the continental United States. An increased incidence of diabetes of the old-age type has been noted in the Marshallese, but no more so in the exposed than in the unexposed population. Fertility Growth and DevelopmentStudies It has been difficult to evaluate the effects of exposureonfertility. During the early period after exposure there may have been somerelative infertility. However, the birth rate of the exposed groupsoverthe past 15 years indicates no noticeable effects on fertility (see Table 7) since it has been about the same as that of the comparison population. No radiation-inducedsex ratio alteration has been seen. Anthropometric measurements and radiographic studies for bone age on the children have revealed slight retardation in growth and development in boys exposed on Rongelap at age <12 years, particularly in those exposed at age 12 to 18 months. Only slight immaturity was noted in similarly exposedgirls. Male children born to exposed parents have shown slight growth retardation andslightly lower levels of peripheral blood elements compared with male children of unexposed parents, but the latter finding has not been evident since 1963. The slight growth difference did not appear to justify the conclusion thatit is associated with exposure of the parent. In 1965 marked hypothyroidism with atrophy of the thyroid gland be- Miscarriages, Stillbirths, Genetic Effects The incidence of miscarriages andstillbirths in the exposed women was about twice thatin the unexposed women duringthefirst 4 years after exposure. Nodifference has been noted since then