a . In the following descriptions and comparisons of the data, findings in the exposed groups are usually expressed in terms of per cent of the appropriate control group. It should be noted, however, that in observational studies of this kind, unknown factors could possibly account for part of the differences noted between the control and exposure groups even (hough all possible measures were taken to select a comparable control group, Inaddition, if was not possible to obtain morethan a single blood sample on each control individual. For these reasons, statistl cal tests of significance were applied mainly to time changes within an exposure group, and not to differences between control and exposure groups. For the purpose of detecting significant changes in the hematological pattern, nonparametric tests (i.e., statistical tests for which it is By , . not necessary to specify the functional distribution of the variate under study) were used.2-4 The advantages of nonparametric methods have been summarized,“ 4.4 HEMATOLOGICAL FINDINGS, GENERAL Total leukocyte, neutrophile, lymphocyte, monocyte, platelet and eosinophile counts for the severai exposure groups are given by day and by age in Tables 4.2 to 4.5. The meantotal white eS : count, neutrophile, lymphocyte and platelet counts at the times of peak depression (time over which counts were consistently the lowest) are shown in Tables 4.6 and 4.7 (pp 78 and 79) for each individual in the Rongelap and Ailinginae groups, respectively. Hematological findings as a function of time and age are shown also in Figs. 4.1 to 4.8, The cumulative distribution curves for the various exposure groups, using the average of counts obtained over the period of maximum depression (days 39 to 51 for leukocytes; days 26 to 30 for platelets) are shown in Figs. 4.9 to 4.11.* In the figures emphasis is placed on the individual blood elements rather than on the total leukocyte count, since the component elements have distinct and different i. . time trends after irradiation. Table 4.2 RONGELAP GROUP MEAN BLOOD COUNTS BY DAY AND'BY AGE + W.B.C. 3 «5 95 Neutrophiles Lymphocytes 3 <5 5 Platelets 3 : <5 ‘ 95 <15 545 Monocytes -7~(. 10°) <5 25 Evsinophiles x «5 10% 5 3 7 10 12 15 18 22 26 30 9.0 4.9 6.6 5.9 5.9 6.7 7.0 5.7 7.0 8.2 6.2 7.1 6.3 6.5 7.2 7.4 6.1 78 6.4 4.7 1.8 2.2 3.5 3.5 3.2 3.4 4.3 3.0 4.0 4.5 3.9 4.1 4.7 5.0 3.9 6.3 2.6 2.1 2.1 1.7 2.4 1.9 2.4 21 2.6 21 2.3 1.8 4.2021 a G5 6.2 1 Sb 3.2 2.0 17.9 14.6 1.7) 1.6 2.4 2.2 ou 5.7 5.5 3.00 det 2.6 2.0 23.6 21.6 ao OD Go 1.0 43s 47 Al 56 G3 0 74 . Majuro Controls h.2 5.9 6.7 7.0 7.7 7.6 4.2 6.8 5.6 6.0 6.0 6.5 13.2 9.7 2.0 2.6 2.6 4.5 39 3.8 2.6 3.3 3.5 3.5 3.6 4.0 4.8 4.8 2.9 3.4 340 3.7 3.7 3,3 . 27.5 22.1 26.1 23.0 16.2 12.6 13.3 19.8 19.6 14.7 10,9 11.5 29 2.4 2 2.4 2.3 2,2 25.0 21.8 26.8 20.6 24.2 18,2 7.4 41 38.5 30.8 2t.8 191 0.8 0,3 0.1 0.7 2.9 1.7 4.2 5.4 3.0 2.9 2.7 1.7 1.9 2.0 18 1G eR) 1.6 1.6 1.9 19 Llo13 3.5 1.6 2.3 1.8 1.80 1.38 BA 22 Lt 1.0 25 1.7 0.5 oat 1.0 1.6 1.2 0.9 28,1 21,1 2.0 2.0 65 _ : 1.4 OK LAL Ob 0.8 0,7 0.3 06 34019 9.5 4.7 *In the Utirik group the cumulative distribution curve for platelet counts only is presented since hematologicaldeterminations in this group were not made during the 39 to 51 day period, used for leukocyte comparisons among the other groups. . i t