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AGE AT EXAM (yrs)
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Figure 19. Counts of subcapsularflecks (made as described in the text) averaged
within each exposure group for persons of similar age. Left: Unirradiated Marshallese people. Right: People exposed to 175 rads fallout radiation in 1954.
Results
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The fleck counts were analyzed separately for
males and females, and, within each exposure
group, were averaged for consecutive intervals of
age to produce age-specific subgroups. The average
fleck count andstatistical limits extending one
standard errorto either side were then computed
for each subgroup.(Persons over 61 years of age
were omitted.) The results are shown in Figure 19
for the controls and for the irradiated individuals.
Each subgroup of the latter is connected by a
solid line to its presumed location on the (broken)
control curve at irradiation 15 years prior to this
examination. The individual fleck counts arelisted
in Appendix 3.
{In the nonexposed females the numberoflens
flecks rose rapidly during adolescence but at a
muchslowerrate thereafter. Females aged 13 to
20 years at exposure exhibited the greatest difference from their nonexposed counterparts. (Fleck
counts were not obtained on persons <_15 years
of age, but would likely be lower than in persons
>> 15 years of age.) Females who were mature at
exposure also yielded fleck counts higher than
those of comparably aged nonexposed females, but
the difference wasless. (Twofleck counts >150
were excluded from analysis.)
Nonexposed males had fleck counts that increased with age, but in contrast to that for nonexposed females,the rise was slower and appeared
to be linear with time. Males exposed to 175 rads
were the smallest group, which may contribute to
the erratic fleck counts obtained.
Thelevels of confidence were generally low because of the nature of the examination and the
numbers of persons examined. Confidence at the
95% level was found only between nonexposed
majes averaging 16 years of age and (1) the oldest
nonexposed male subgroup, and (2) 175-rad exposed females older than 25 years at examination.
Although somefine structure has been implied,
the results for each group can be represented by a
straightline.
Discussion
The primary findingin this survey was the continuousincreasein lens flecks with age in nonexposed males and females. Whereas the increase for
females was more rapid during adolescence, lens
flecks in males rose at a lower but constantrate,
consequently, fleck counts in males did not equal