34
‘population. The findings also support the program
of thyroxine replacement in che exposed Rongelap
population to prevent both clinical hypothyroidism andtheassociated rise in plasma TSH, which
may be tumorigenic.
wassignificantly lower (6.02°1.8 ug/dl). Thefrequency distribution calculations (see Table 29 and
Figure 39) indicate that a substantial portion ot
the Utirik population has plasma T, concentra-
don <5 yug/dl. Measurements of plasma tri-
iodothyronine (not shown) showed similar reductions in those patients with low T,4 values. Plasma
During the 1973 survey, T,4 and TSH concen-
40
trations were measured in plasma from 109 unexposed Rongelap and 97 exposed Utirik subjects
(see Table 29). The mean Ty, in the unexposed
Rongelap group, 7.7 ug/dl, was the same as in
March 1973
Group
109 Rongelap
unexposed
97 Uurik
exposed
Plasma T,,
pe/dl -
Subjects
with value
<5.0
Subjects
with value
>IL3
7.72.0
6%
6%
6.01.8"
32%**
6%
“Significantly different, 2<~0.001.
"*6% had values < 3.8.
T
]
7.5
10.0
12.5
RQ.
t
‘
‘
‘
‘
\
S
r
30
|
% oftatal pop ulation
Plasma Thyroxine Concentrations (Mean + 5.D.)
in Utirik and Unexposed Rongelap Populations,
]
March 1973
the plasma T.4 concentrations were skewedto the
Table 29
Tr
e-—e Rongelap
the United States, and, as in the United States,
upper range. In the Utirik group, the mean Ty
T
e---e8 Utirik
[ws
4. Thyroid Function in the Utirik and
Unexposed Rongeiap Groups
10
25
30
Plasma thyroxine (2¢/100 ml)
Figure 39. Percentages of people in Utirik and in Rongelap unexposed groups having given thyroxinelevels, 1973.
Table 30
Thyroxine-Binding Globulin (TBG) Levels
(Mean = S.D.) in Serum, 1973
TBG by RIA
Group
Rongelap
Exposed
Unex
All sera
All sera*
Uurik
All sera
_ Allsera*
capacity
mg/dl
n
pg T,/dl
12
13
29
22
1.450.354
1.822-1.22
1.64+0.95
1.340.45
14
1400
25
21
21.52 69
-25.32215.7
«23.1 ths
IS.1= 62
22
1.400.42
1.40--0.42
a
TBG-binding
n
22
T'BG capacity
—
31
27)
18.9 78
«16.4 43
*Omicting sera with TBG>3 or TBG-binding capacity
> 30.
Statistical comparisons revealed no significant differ-
ence ( p>0.05) berween any of the groups.
J0bet oI
Figure 40. Thyroxine-binding globulin levels
in serum and TBG-binding capacity, 1973.
4|
|
4