39
bv Hempeimann. 07.109 Risk for thyroid cancer in
the Rongelap people is also similar to that re-
dence of thyroid lesions and the estimated dose to
the gland. On the basis of the incidence per rad in
the high exposure Rongelap children. about 2
children with adenomas would be expected in the
levels involved there is a correlation between inci-
Utirik group, where none was found. The lower
effectiveness per rad in the Utirik children may be
Marshallese children appears similar, on a risk per
rad basis, to that in the x-raved children studied
Ailingnae group, where 2 were noted. and + in the
ported for other populations.
The dara in Table 25 indicate that at the dose
Table 33
Percent Incidence of Thyroid Lesions (20 Years Observation)
Age at exposure
<10 yr
Group
Rongelap
Ailingnae
Rongelap & Ailingnae
Utirik
X-rayed children (17 yr)107
X-rayed children, low dose (17 yr)!07
Marshallese controls
Benign
Cancer
Benign
84.2
33.3
76.0
0.0
28.0
3.0
3.3
0.0
4.0
0.0
4.3
0.13
iL.
33.3
15.8
3.1
1.8x 10-5 (all ages)
5.4
1.0
Worldwide av. 108
United States197
>10 vr
2.5 X LO-3 (all ages)
0.36-1.7
Cancer
4.4
0.0
3.5
1.0
1.8 10-5 (all ages)
2.9% 1075 (all ages)
0.5-1.6
Table 4
Risk* of Radiation-[nduced Thyroid Lesions (Cases per 10® man-years per rad)
Age at exposure
< 10 yr
Group(years follow-up)
Rongelap (20)
Ailingnae (20)
Rongelap & Ailingnae (20)
Utirik (20)
Rochester (17)10T
Ann Arbor (17)107
Beach & Doiphin (20)123
UNSCEAR(17)!24
ABCC (20)101
ABCC (20)201
Dose range, rads (type)
> 10yr
Benign
Cancer
710-1150 (18,7)
41.9
43.6
42.1
0
2.6
0
2.3
0
335 (av.) (x rays)
20 (av.) (x rays)
(x rays)
100- 300 (x rays)
20-1000 (y, 2)
<20
(y,")
64.0
24.0
3.5
2.2
17
0.5=15
1.3 (all ages)
0.2 (all ages)
280— 450 (18, y)
280-1150 (TB, y)
60- 9518, y)
Dose range, rads
379
135-190
327
31
Benign
10.5
151.1
22.5
89.2
Cancer
7.0
0
6.4
17.8
*Risk is calculated from the equation
Risk = No.of cases X L08
dose X years at risk
or, alternatively,
.
Risk =
No. of cases x 106
~ No. of subjects x mean dose < mean No.of years at risk”
Both equations give almost identical results for the Marshallese because of the uniformity of the data. No correction
has been made for expected numberof cases because the expectation among unexposed subjects is too low to affect the
results (see Table 33).
VOB o tao