i oH

Table 4.

Age

Estimated thyroid risk due to radiation for exposed Marshallese 27
years after exposure.
(Corrected for incidence in age-matched
unexposed populations. )*

Av.

Nodules

Hypothyroid

group

No.

dose

Total**

Risk

Ca

Rongelap
<10***
>10
Total

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
<10***
6
>10
12
Total
18

379
140
233

1.8
3.1
4.9

29.3
68.3
43.3

58
100
158

384
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

314

19.9

203

1.3

1.8

Utirik
<10***
>10
Total
All

<I0

>10
Total

157
240

,

144
203

9.8
29.7

16.1
22.6

Risk
1.6
5.5
3.5

3.8
5.1

6.2
3.9

_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

32.5

3.0

4.8
7.8

4.3

7.9
5-9

14.6
37.5

23.9
28.6

*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.
*xIncludes also unoperated cases.
*k*Does not include the groups exposed in utero because of dose uncertainty.

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