57
evidence of leukemia or leukemic tendency. One
i aetna
child in the irradiated group had 3% basophils but
no other positive findings. The cardiovascular and
arthritis surveys, as well as the general results of the
physical examinations, have not shown any apparent increased incidence of degenerative diseases
in the exposed people. No radiation-induced
cataracts have been observed in anyof the exposed
people.
Genetic effects have not been specifically studied
because of the small number of people involved.
No apparent radiation-induced genetic changes
have been detected on routine physical examination in the first-generation children of exposed
parents.
Hematological surveys again showed considerable
fluctuation in the year-to-year mean level of leukocytes in both the exposed and unexposed groups.
The mean leukocyte level of the exposed group
showed a marked decrease at the time of the 1960
survey (no unexposed people were examined). The
reasonsfor these fluctuations are not apparent. At
5 years post exposure, exposed people still had
meanplatelet levels 10 to 15% below those of the
unexposed group. However, /ymphocyte levels appeared for thefirst time to equal those of the unexposed group. Mean erythrocyte levels were also
slightly lower in the exposed people. These blood
elements in the Ailingnae group also showed some
slight depression below the unexposedlevels but
not quite so marked asseen in the Rongelapexposed group. A general anemic tendency was
noted in all the Marshallese, both exposed and
unexposed. Price-Jones curves, on the average,
showed a slight microcytic tendency. Serum iron
levels were generally normal. The fact that some
of the blood elements in the exposed group have
not yet returned to the levels in the unexposed
group raises the possibility that a residual radia-
tion effect on the bone marrow persists, but other,
not immediately apparent, factors may be involved.
Studtes ofgenetically inherited characteristics. Blood
grouping studies in the Marshallese showeda relatively high B gene frequency, a high N genefrequency, an extremely high R' gene frequency, and
total absence of Kell and Diego factors. These
characteristics differ from those of Polynesians and
suggest relationship with Southeast Asians and
Indonesians. Haptoglobin studies showed the fre-
quency of the Hp' gene to be higher than in
European populations thus far tested and consistent with populationsliving near the equator.
The distribution of haptoglobin types showed the
population to be relatively homogeneous. Trans-
ferrins in all sera were type CC, the common European type. B-Amino-iso-butyric acid urinary levels
showed the Marshallese to be the highest excretors of this acid of any population thusfarreported. Levels in the exposed group were about
the sameas in the unexposed group,and no correlation was found with body burden level of
radionuclides; this indicates that there is probably
no correlation with radiation exposure. Glucose-6phosphate dehydrogenase of the red cells appeared to
be deficient in the Marshallese. Considerable caution must be exercised in evaluating the results of
these studies on genetically inherited characteristics because of the small number of samples
tested. The data do seem to indicate relative
homogeityof the population and closest kinship
with people of Southeast Asia. These data also
may be useful as a base line should genetic changes
appearin later generations, possibly related to
radiation exposure.
Results of other laboratory studies carried out
during the 5-year survey included the following:
Serum protein levels, as has been noted before, were
generally on the high side of normal; the reason
for this is not apparent. Complementfixation studies
for parainfluenza 1, 2, and 3, respiratory syncitial,
psittacosis, and Q fever showed antibodiesto all
groupsof viruses except that for Asian influenza,
which probably had notyet seriously involved the
people of the Marshall Islands. The antibodytiters
appeared to be somewhat lower in the exposed
people. Sodium levels in the urine and food indicated
about the same consumption of NaCl as in Americans. The generally lower incidence of hypertension in the Marshallese might be related to the
fact that the former native diet was probably lower
in salt content than the present, more westernized
diet. It will be interesting to see whethertheincidence of hypertension will later increase. Repeat
studies ofprotein-bound todine, total iodine, and butanol-
extractable iodine of the sera showed levels lower
than previously reported, and the previous higher
readings are thoughtto be in error because of con-
taminated glassware, although somereadings were
still somewhat high. Fourcases of glucosuria associated with elevated blood sugar were found in the
unexposed population, which indicated a rather
—e
counts and types, alkaline phosphatase staining,
and basophil counts of 4000 white cells showed no