45
Correlation of Data. [n order to place all the
data on a common basis for comparison and combination, the data were converted to a percentage
basis for each criterion. In the case of the measured data, values associated with least aging were
taken as 0% (sometimes the highest reading, as
each light as it appeared. The total time necessary
to extinguish all the lights was measured. Thistest
involved both manual dexterity and mental reaction time”? (see Figure 33). (4) Hand Strength. The
spring tension of the hand grip was measuredin
kilograms with a Smedly hand dynamometer.”
The maximum squeeze strength in the dominant
with hand strength; sometimesthe lowest, as with
hearing loss), and conversely the values showing
most aging were taken as 100%. The estimated cri-
hand in 3 tries was recorded.
Miscellaneous Tests. (1) Body Potassium Levels
('°A). Since loss of muscle mass occurs with aging
and total body potassium is closely related to
muscle mass, it has been shown that bodylevels of
potassium decrease with age.’*-'* Whole-body
spectrographic analyses were carried out in the
Marshallese in a lead-shielded structure. In this
way '’K levels were obtained and presented as
K/kg body weight. The accuracy of these data
could have been improved by obtaining moreprecise determinations of lean body mass, such as by
measurement of body water.’ The valueslisted
are averages of the 196! and 1965 determinations.
(2) Blood Serum Cholesterol Levels. These were obtained in 1957 on sera sent to the United States.**
teria with values of 0, 1+,2+,3+, and 4+ were
presented as 0, 25, 50, 75, and 100%, respectively.
The data were examined on an individual basis as
well as on a population basis, and comparisons
were made largely by using means for each decade
age group. Except where indicated, the data used
were collected during the 11- and 12-year surveys.
An analysis of variance was used to determine
differences among the factors of sex, age, and radi-
ation levels.* These data were programmed and
analyzed on a high speed digital computer.** For
each criterion, the combined score over sex and
radiation level was correlated with age. A curve of
*Mr. Keith Thompson of Brookhaven Nationa! Laboratory
did the statistical analyses of these data.
**The Control Data Corporation 6600, at Brookhaven National Laboratory.
"S.H Stoelting Co., Chicago, HI.
*' Che analyses were done at the National Institutes of Health
by Dr J.H. Bragdon and Mr. J.C. Lauter.
Table 22
Correlation of Criteria With Age and Radiation Exposure
Correlation
—
0.87
0.83
+17.0
0.0
N.S. (0.70)
NS. (1.00)
0.70**
— 1.4(M), + 24.6(F)
N.S. (0.90, 0.20)
(r value)
Grayness
Arcus senilts
Accommodation
Skin retraction
Skin looseness
0.81
0.74
0.70
Vibratory sense (M 4+ F)
Correlation with radiation
with age
Percent
Significance® ( p)
~14.1
+ 73
+ 1.6
Visual acuity
0.69
Hand grip (M+ F)
0.677"
+13.8(M), +13.8(F)
('.99
+ 7.0
Hearing loss
0.67
Reacuon time (M + F) (light extinction test)
Ssstolic blood pressure
Potassium (M + F)
(Cholesterol
Neuromuscular function (MI +-F) (hand tally)
Combined scoret
*N.S. = not significant at 5% level.
0.64**
0.55
O.41**
0.39
0 467*
+ 14.0
+ 7.Y
— 2.0(M)}, -- 10.5(F)
—11.5
— 14.6(M), + 10.6(F)
—17.2
+ 3,2(M), +1.1(F)
**r values for males and females averaged.
N.S. (0.11)
N.S. (0.68)
NS. (0.82)
N.S. (0.59)
N.S. (0.40)
N.S. (0.15, 0.18)
N.S.
N.S.
N.S.
N.S.
N.S.
(0.88, 0.55)
(0.30)
(0.17, 0.22)
(0.05)
(0.85, 0.95)
N.S. (0.27)
tWeighted according to r value.