2.
women during the first five years.

Aging studies did not reveal any radia-

tion-induced senile changes or reduced longevity.
cataracts were noted,

No radiation-induced

Lymphocytes, cultured from peripheral blood reveal~

ed a low incidence of chromosome aberrations in the exposed people at ten
years after exposure,

During the second decade of examinations, there have been serious
developments not only related to medical findings but also to transporta-

tion problems and political interference.

|

Thyroid: - Growth retardation had been noted earlier in some of the
exposed Rongelap children but correlation with thyroid injury was not
established since laboratory tests then available for evaluation of ~~
thyroid. function were normal.. Early estimation of-thyroid dose from absorbed radioiodines in the fallout led to the mistaken belief that it
was too low to expect late effects on that organ.

Reevaluation of the

dose in 1965 showed that young Rongelap children probably received thyroid
dose of 700-1400 rads and aduits about 335 rads, including the ganma dose.
The smaller size of the children's thyroid largely accounted for the greater
dose.

At about this time (1963) thyroid tumors began appearing in children

and to a lesser extent in adults.

More refined tests of thyroid function

became available and provided laboratory confirmation that some children had
reduced function of that gland,
their growth retardation.

Thyroid injury was shown to be the cause of

More thyroid tumors continued to develop and at

the present time 29 of 86 exposed Rongelap people (about 1/3) have developed
thyroid abnormalities.
in the U.S.

Surgery on 25 of these people has been carried out

Three women were found to have malignant tumors.

During the

past year benign tumors were reroved from a boy who had been exposed in

utero.

Most of the Rongelap people have been on thyroid hormone treatment

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