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it must have been prepared in the period of 1977 to 1979 when ws received it. It was noted that there are apparent inconsistencies ZZD9Z for the Marshall Islands for the period 1955-1975 and Table 111-5 gi’v’es data for the infant mortality rate for 1976. In Ta51e III-1 , the infant death ra”~ per 10!)0 births for 1970 through 1975 is given as 2S.3, 33.5. 25.4, Q6.4, 21.1 and 37.0. However , Table III-5 indicates the infent in the following estimates; because it is more co,mplete and it provitiss a self-consistent set of dzta. Howsver, in view of the discrep?nci~s, “=:;;;V#;;PzJ. “n view of the uncertainties in the risk ~nere is also a bias built into the data beczmse of the inclusio of Ebye and !lajaro in the overall ?larshall . Island rates. This arises from the different death rates (particul=?ly infants) at’ the%- two locations. A h 1 2. ‘ lnf~nt death rate A 13.2% per birth. 3. Overall death rztek O.5~5 ?er year.
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A population of 550 was assund .he one that ~ move back to m - Values for other initial populations m+y+#05t.ained by rati~s of the results. The total population at the end of 30 years is given by the The number of births in 30 years are given by: where x is the time between O znd 30. This gives Similarly, the number of deaths in the 30 year psriod would be: ceded is the reduction in 30 Y?Z? dose to those born after the return because of the decrease in radiation levels arid the smaller au~ount of time in the 30 year period that is spent on the island. For, this, the total ~yulation dose for thosa born aft~r returning asslJ.~ing an initial dase rate of 1 rad/year is giv~n by:
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I is the half-life of decrease of the radition dose, taken here as 30 & ~~;s ?Lntesral cznnot be %Ived anal fiicalj An approximate solutian was obtair?f%l by calculatin~ this function for each of 30 years and summing. This gave 8949 rads for the total population includin% the original 550. Th; total dose received by the original 550, ass~ing that all live for the 30 years, is For those born after the return, the population would be the difference between the total population in 30 years, the number of deaths and the original 550 ?eoPle or 1134. Thus , the per capita dose for this group is 8949/113~ = 7.9 rads. For the original 550, the w capita do.s5 is 11,902/550 = 22 rads. The ratio of these two to give an estimate or the fraction of t’ne full 30 year dose received by the The assu..ption of no deaths in the original 550 returning was made for simplic~ty and the lack of good death rate data. the age characteristics of the Marshallese frcm Table IV-3 and he U.S. population in 1970. This comparison is given in the attached curve. ~%e slopes —. are similar above age 35 but the magnitudes are distorted by the high. birth rate irI the Marsha in ~er~s of the re~ativ.% L are similar, the relative risk for people above 35 in both PoPulati~ns hwould be similar because most of the cancer occurs at age ~a out 40 and above. Hcwever, the magnitude of the relative risk in the U.S. used for the Marsh:,~lese will be high by a factor of scmewhere around 2-3 because of the distortion caused by the very hish proportion of youn3 people who have a rel.ztively low natural czncer incidence.
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