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The Medical Research Center _
Brookhaven National Lehoratory
Upten, L. L, New York
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BOX No. +
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AN ATTEMPT TO QUANTIFY SOME CLINICAL CRITERIA OF AGING*
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ROBERT A. CONARD, M.D.
(From the Medical Research Center, Brookhaven National Laboratory, Upton, L. 1. New York)
Among thepossible late effects of ionizing
radiation exposure are shortening of life span
and a process resembling premature aging. In
animals these effects are evidenced by such
changes as graying of the hair (7), appearance
of degenerative changes in tissues and organs
(1, 2). and deaths associated with degenerative
diseases and malignancies (6). Although evi-
dence for premature aging per se has not been
observed in human beings, shortening of life
span and increased incidence of malignancies
have been reported in radiologists (10, 11).
Japanese exposed to nuclear bombings have
shown an increased incidence of leukemia (9).
Another human population which received sig-
i
ww
nificant radiation exposure are the people of
Rongelap Atoll in the Marshall Islands, who
were accidentally exposed to fallout in 1954.
In view of possible effects of radiation in producing premature aging, during the course of
studies of these people it was desirable to develop a method of measurement of aging. It
seems pertinent first to briefly summarize the
radiation effects in the Rongelap people. since
they were the subject of this study.
A group of 64 Rongelap people received an
estimated 175 r of gamma radiation in addition
to beta burns of the skin and someinternal absorption of radionuclides. Also 18 other Rongelapese who, by virtue of being away on a nearbyisland, received only an estimated 69 r. Due
to radioactive contamination of their homeisland, the people of Rongelap were moved to
Majuro Atoll where they lived for the following
three years. They returned to Rongelap in the
summer of 1957 accompanied by some 100 un-
exposed Marshallese relatives who had not been
living on the island at the time of the accident.
This group served as an excellent comparison
population. Both groups have been carefully
studied at intervals for signs of radiation effects.
The acute damage (such as hemopoetic depres-
sion, and skin burns) which have been described
in previous publications (3, 4, 5) has largely
subsided, and greater emphasis is now being
placed on detection of late effects of radiation.
* This work was done under the auspices of the U. S. Atomic
Enersy Commission.
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COLLECTION
Shortening of life span has not been apparent
thus far. Four deaths have occurred: one in a
46-year-old man during the second year after
exposure from hypertensive heart disease, which
had been present at the time of exposure; the
second in a 76-year-old man at three years
post-exposure of coronary heart disease complicating diabetes of long standing; the third in a
36-year-old man 4 years after exposure with
acute varicella; and the fourth in a 61-year-old
female at 5 years after exposure of ovarian cancer. None of these deaths seemed to be directly
related to radiation effect, and the incidence of
mortality is about the same as for the Marshall
Islands as a whole. No case of leukemia or
cancer, except the one case of cancer referred to
above. have occurred. The incidence of degenerative diseases seems to be about the same in
the exposed as in the unexposed group. Reproductive capacity does not seem to have been
impaired in the exposed group. A slight increase in the number of miscarriages andstillbirths seems to have taken place in the exposed
women but, due to lack of vital statistics, this
cannot be properly evaluated. There also was
suggestive evidence of a slight lag in growth and
development of exposed children during the
first few years post-exposure, but this is being
re-evaluated based on better age data. No
genetic effects have been observed in the chil-
dren born of exposed parents.
Although there has been no outward evidence by gross observation of any accelerated
aging effect of radiation on the exposed group,
it was believed that it would be desirable to
have measured criteria of possible age changes
that might occur on normal physical examination. Therefore the over-all objective of this
study was to establish a series of tests to evaluate any possible radiation-induced senescence
in the exposed group compared with the unexposed population living on the sameisland.
However, a study of the data to be presented
that was collected during the past survey
(March, 1959) 5 years after exposure showed
no apparent differences between the exposed
and unexposed groups. Therefore the two
groups have been pooled with the objective of
| RéprittJhrdth Journal of Gerontology. Vol. 15. Ne. 4. Oct., 1960—Printed in U S.A.