- 4 only a very slight increase, if any, in non-cancer thyroid nodules in the
Utirik people.
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 to 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 studies
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.
there are many facts about radiation that are not known,
number of scientists
thirty years.
Even today,
despite the large
that have studied this subject for the past
twenty or
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, were justified in saying that they did not expect radiation
effects to develop in the Utirik people.
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