i+ Table 7 Mortality. 1954-1966. by Age as of 1954 Group Age: Rongelap (175 rads) Ailingnae (69 rads) Unexposed ** <10 0-19* 0/6 0/56 11-20 21-30 31-40 1:13 0-10 0/5 O-l 0/28 0° 0,30 *Mortalitv/number in group. neck and face complicating diabetes, and a 68year-old woman (No. 894) died of pneumonia complicating Asiatic influenza. A 91-year-old male (No. 862) died presumably of cardiovascular disease; he had been quite senile and bedridden for the past few years. During the past 12 years, 13 deaths have occurred in the exposed group. This represents 13.0 deaths per 1000 per annum (11.7 for the more heavily exposed group and 18.3 for the smaller Ailingnae group) compared with 8.3 per 1000 for the Marshall Islands as a whole in 1960. In Table 7 mortalities for the exposed Rongelap and Ailingnae groupsas well as the unexposed comparison population are presented according to decade of death. A x’test for sig..ificance,* comparing groups of exposed and unexposed people, showedthat the mortality in the Ailingnae group alone was significantly greater than in the control group. The Rongelap exposed group combined with the Ailingnae exposed also showed significant difference compared with the unexposed. These results should be interpreted with caution since the numbers of people involved are too small for a sensitive statistical test. None of the deaths in the exposed group canberelated directly to radiation exposure. The causes of death are similar to those in the unexposed population. Theslightly greater mortality in the exposed Rongelap people maybe related in part, at least, to the larger percentage of older people originally in this group. No cases of leukemia have appeared in the exposed population. Twoearlier deaths from cancer in exposed women and the recent development of a malignant thyroid nodule, to be described below, make it necessary to keep in mind the possibility of causal relauonship with radiation exposure. *We are grateful to Mr. Keith Thompson of Brookhaven National Laboratory for carrying out the statistical analyses. 41-50 27 1.5 2.18 Of 1 3.21 31-60 2/5 0/1 3/17 61-70 71-80 >80 1 2/3 Lyi 3/3 2°7 Of1 1] **This group was not examined until 1957. Births Twelve babies were born to exposed parents and 13 to unexposed parents during the period between March 1964 and March 1966. The birth rate per year is calculated from the numberof births per womenofchildbearing age (15 to 45). There were 30 such womenin the exposed group (including 3 unexposed women whose spouses are exposed males) and 32 in the unexposed group (see Table 8). From these data, there appears to be no difference in fertility between the two groups. All these babies appeared normalexceptfor the ~ two listed below, who were both offspring of unexposed parents. Congenital Anomalies. “Two abnormalbabies were noted during the 1965 survey. One was a hydrocephalic (No. 1061) and the other a mongoloid (No. 1055). Sex Ratio. Table 9 lists the births by sex in re- lation to the exposureof the parents. There appears to be no radiation-induced sex ratio alteration. Miscarriages and Stillbirths. A total of 5 mis- carriages occurred overthe past 2-year period, all in unexposed women, one of whom (No. 959) had 3. As had been noted earlier, the exposed women had a somewhatgreater incidence of miscarriges and stillbirths over the first 4 years post exposure (see Table 8). During 1954-58 the exposed women had 13 miscarriages of 32 total pregnancies (40.6% incidence), and the unexposed women had 8 miscarriages in 49 pregnancies (16.3% incidence) during the 4-year period 1956-60. A x’ test for significance* showedthat total miscarriages and stillbirths were significantly greater (at the 5% level) in the exposed women compared with unexposed duringthefirst 4 years, but there was nosignificant difference after this period. Since 1958 the exposed women have had 5 miscarriages in 48 pregnancies (10.4%) and the unexposed women LO miscarriages in 62 pregnancies (16.1%).