Table 4. Age group Estimated thyroid risk due to radiation for exposed Marshallese 27 years after exposure. (Corrected for incidence in age-matched unexposed populations. )* Nodules Hypothyroid No. Av. dose Total** Risk Ca 19 45 64 1000 387 569 14.6 2.5 17.1 28.5 5.3 17.4 0.8 2.6 3.4 Ailingnae <LO**e* 6 >10 12 Total 18 379 140 233 1.8 3.1 4.9 29.3 68.3 43.3 58 100 158 84 35 53 3.5 4.2 7.7 26.6 44.4 34.1 0.5 1.2 1.7 3.8 12.7 7.5 83 157 240 314 144 203 19.9 9.8 29.7 28.3 16.1 22.6 1.3 3.8 5.1 1.8 6.2 3.9 Rongelap <1Q*«* >10 Total Utirik <1O*** >10 Total ALL <10 >10 Total Risk 1.6 5.5 3.5 No. All Risk No. Risk 3 3.8 6.8 5.8 8.1 6.9 17.6 6.3 23.9 34.3 13.4 24.3 1.0 1.0 22.0 8.8 1.8 4.1 5.9 29.3 90.4 52.1 3.5 4.2 7.7 26.6 44.4 34.1 22.9 14.6 37.5 32.5 23.9 28.6 3.0 4.8 7.8 4.3 7.9 5.9 *Since it is possible that the thyroid doses used may be too low, on the basis of reevaluation analyses now in progress, the above risk estimates may be too high. If the actual years at risk were used, i.e., years until development of abnormality or death, the total number of years would be reduced and the risk factors would be higher. The cancer risk is probably underestimated since a number of people with nodules were not operated upon. The risk for benign nodules was not included since a large number of unoperated cases were likely to have been benign. **Includes also unoperated cases. ***Does mot include the groups exposed in utero because of dose uncertainty. - 133 -