LATE EFFECTS OF RADIOACTIVE IODINE IN. FALLOUT
in 1965, were in the range that we find in
the northeastern United States. In 28 sam-
TABLE 6.
.
ples, the 24-hr urine excretion was 19 to
Column Chromatographic Analysis
of Serum Iodine*
Group
279 wg with a mean of 105 pg. This indi-
No.
Total Todo T. + Tif
Samples Iodine protein
cated that there was no excessive intake of
iodine in the Marshall Islands that might
be related to the iodoprotein in the blood
and, secondly, that there was no deficiency
of iodine that could be related to the later
development of goiters. The thyroxinebinding capacity of the thyroxine-binding
alpha globulin (TBG) was also measured
in sera with elevated PBI levels, and no
elevation was found. An increase in TBG
could explain an elevated PBI but not a
high serum todoprotein level.
To conclude with this part of the study,
the detection of a high blood iodine in
Marshallese was an unexpected finding, one
that ts still not explained. People living in
the Marshall Islands, for reasons that are
not known, have an unusual elevation of
serum lodoprotein.
When Dr. Rall went on one of the expeditions to the Marshall Islands in March
1965, the situation with the abnormal PBIs
was known, and he decided to look a little
TABLE 7.
Case No.
Total Iodine
North Americans
25
+pg/ 100 mi
7.0
2.2
5.1
0.8
4.5
3.8
* Average values.
ft Ts = thyroxine, T, = triiodothyronine.
further into the iodine metabolism in these
people. He was more interested in the abnormality in Marshallese in general than he
was in abnormalities that might exist in the
people who were beginning to form nodules
just about this time, and all of these studies were done on individuals without nodules. There were 21 Marshallese (all adults)
who were studied. Twelve of them were in
the exposed group; 9 of them were never
exposed to radiation. The results presented
in Table 8 showed no difference between
these groups of individuals, and they are
compared with average normal values that
we would find in the United States.
These studies were done with 1873; this
isotope was used because of the very low
PBI*
3.2
3.1
3.
17
1.8
24
64
Tilt
Iodoproteint
10.8 [9.1]
8.2
11.8
1.0
1.8
1.9
<0.5
(2.2)
(1.3)
(1.9)
(> 1.3)
1.3
<0.5
(>0.8)
5.7
1.7
(4.0)
6.5 [4.6]
3.2 [3.3]
5.0
69
59
68
19
ug/l00 ml
5
65
Thyroidectomized§
34
Marshallese
Serum Iodoprotein Leveis in Relation to Thyroid Function
Hypothyroid§
3
Levothyroxine treated]]
1231
2.0
5.3
5.8
2.9
2.8
6.0
Ee TE Ter ae eee
‘Volume 66, No. 6
June 1967
* PBI = protein-bound iodine.
} Tal = thyroxine iodine.
{t Iodoprotein levels in parentheses are the difference between PBI and Til levels. The others were measured
directly by the column method.
starting thyroxine.
re se ee pee ee
§ Levothyroxine stopped approximately 3 weeks before sampling.
{ Treated with levothyroxine, 0.3 mg/day, for 6 months. Values in brackets are determinations made before