56
status of the people in relation to that of the unex-
posed comparison population, particularly in regard to any possible late developingeffects of their
exposure, their hematological status, and theinfluence of the slightly contaminated environment
on the assimilation, excretion, and body burden of
radionuclides.
Medical histortes of the intervals between the examinations in 1959 and 1960 were, for the most
ma
part, uneventful and revealed no major epidemics
of disease. Several deaths had occurred and new
births were reported. In the exposed group, two
deaths occurred and in the unexposed group,
three. Twoof the latter were due to influenza acquired during an epidemic on Kwajalein.
The four deaths that have occurred in the exposed people since exposure represent a mortality
rate of 8.1 per 1000 population, compared with 8.3
for the comparison population and 6.8 for the
Marshall Islands as a whole. A review ofthe birth
rate of the exposed group over the past 6 years
seemsto indicate no noticeable effect of their exposure onfertility. The 24 births represent a rate of
48 per 1000 population, compared with 37.3 for
the Marshall Islands (1957). The 20 births over a
3-year period for the comparison population represent a rate of 62 per 1000 population. A somewhat greater incidence of miscarriages andstillbirths
has been noted in the exposed women, but because of the paucity of vital statistics in the Marshallese and the small number of people involved,
the data are not readily amenable to statistical
analysis.
Physical examinations showed the exposed and the
unexposed people to be generally in a state of good
health. No diseases were noted that could be
directly related to radiation effects. The incidence
of various disorders in both adults and children
was about the same in the exposed and unexposed
groups.
In connection with growth and development studies,
a project on the verification of accuracy of ages of
the children has not been completed and, therefore, the suggestive evidence previously presented
of possible lag in statural growth in the exposed
children must await confirmation. It was noted,
however, that in the 6-year chronological age
group, three boys and onegirl out offive boys and
two girls in the exposed group exhibited significantly retarded skeletal maturation as judged by
x-ray examination. The birth datesof these children seemed to befairly well established.
A cardiovascular survey of the adults showed no
outstanding differences between the exposed and
unexposed groups. The people appeared to have
less hypertension on the whole than is noted in
people in the continental] United States.
Anarthritis survey showed no greatdifferences between the exposed and the unexposed people, and
about the sameincidence as is seen in American
populations.
An ophthalmological survey showed no remarkable
differences between the exposed and unexposed
groups except possibly a slightly greater number
of cases of pterygii, pingueculae, and corneal scars
in the exposed group. It is not know whetherthis
finding is of any significance in relation to their
radiation exposure. Slit-lamp observations showed
no opacities of the lens characteristic of radiation
exposure. As a whole, visual and accomodation
levels in the Marshallese appeared to be above the
average in the U.S. population.
A dental survey showed nosignificant differences
in either caries rate or incidence of peridontal disease between exposed and unexposed groups. The
poororal hygiene generally observed in the Marshallese had its usual results, namely, high caries
rate in teen-age children, severe peridontal lesions
in adults (heavy calculus and loss of alveolar
bone), and edentulous mouthsin the aged. Radia-
tion exposure did not appearto haveaffected developing dentition in the exposed children.
Late effects ofradiation. Various parameters usually
associated with aging were measured or estimated
on a0 to 4+ scale (skin looseness, elasticity, and
senile changes; greying of the hair and balding;
accomodation, visual acuity, and arcus senilis;
hearing; cardiovascular changes including blood
pressure and degrees of peripheral and retinal
arteriosclerosis; neuromuscular function; and
hand strength). Comparison of these measurements in exposed and unexposed individuals of the
same age groups showed no apparent differences.
A biological age score was calculated for indiviuals
and groupsbv use of an average percentagescore.
Life shortening effects of radiation have not been
apparent. As noted, the mortality rate was about
the same in the exposed as in the unexposed
people.
The onecase of cancer that developed in the ex-
posed group occurred at 5 years after exposure,
too soon, it is believed, to bear any particularrela-
tion to radiation exposure. Leukemia surveysincluding physical findings, studies of white cell