DRAFT 7 A only a very slight increase, Utirik people. if any, in non-cancer thyroid nodules in the The three cases of thyroid cancer in the Utirik people compared with four in the Rongelap people is definitely higher than expected based on the estimated dose. not known, The reason for this discrepancy is However, we have reviewed the data and have found no reason to change the estimates of the dose te the thyroids of the Utirik people. The number of cases observed may vary above or below the average number expected - the variation being larger as the population size decreases. In a small population such as Utirik the difference between the predicted and observed number of cases may be substantial. Of course, thyroid cancer occurs in populations not exposed to radiation above the natural background. The incidences of radiation induced thyroid cancer varies with different population groups. _For example, in children the risk rate (in number of cases per million people per rad per year) varies from 0.5 to 1.5 reported by the United Nations to 5.5 for a group of Americans in New York. It is essential to know the natural incidence in the Marshallese and larger studics of such incidence have been initiated. Even though it was known that the dose to the thyroid glands was higher than to the rest of the body, what was not known during the earlier years was the degree of sensitivity of the thyroid gland to radiation. Even today, there are many facts about radiation that are not known, despite the large number of scientists that have studied this subject for the past twenty or thirty years. Even less was known about radiation in 1954 at the time of the exposure to the people on Rongelap and Utirik. Only relatively recently has the degree of sensitivity of the thyroid for developing tumors from radiation exposure been appreciated. ‘Therefore, the physicians examining you in past years, based on the best possible medical information available at that time, vere justified in saying that they did not expect radiation effects to develop in the Utirik people, MMMM ek kart