45
each light as it appeared. Thetotal time necessary
to extinguish all the lights was measured. Thistest
involved both manualdexterity 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
hand in 3 tries was recorded.
Miscellaneous Tests. (1) Body Potasstum Levels
Correlation of Data. In order to place all the
data on a commonbasis 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
with handstrength; sometimes the lowest, as with
hearing loss), and conversely the values showing
- most aging were taken as 100%. The estimated cri-
(*°K). 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 determinationsof lean body mass, such as by
measurement of body water.** The values listed
are averagesof the 1961 and 1965 determinations.
(2) Blood Serum Cholesterol Levels. These were ob-
teria with values of 07, 1+,2+,3+,and4-+ were
presented as 0, 25, 50, 75, and 100%, respectively.
The data were examined on anindividual basis as
well as on a population basis, and comparisons
were madelargely by using meansfor each decade
age group. Except whereindicated, the data used
were collected during the 11- and 12-year surveys.
An analysis of variance was used to determine
differences amongthefactors 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
tained in 1957 on sera sent to the United States.**
*Mr. Keith Thompson of Brookhaven National Laboratory
*S.H. Stoelting Co., Chicago, HL,
**The analvses were done at the National Institutes of Health
by Dr. J.H. Bragdon and Mr. J.C. Lauter.
did the statistical analyses of these data.
**The Control Data Corporation 6600, at Brookhaven Na-
tiona! Laboratory.
Table 22
—
Correlation of Criteria With Age and Radiation Exposure
ee
Correlation
with age
(r value)
Grayness
_Arcussenilis
Correlation with radiation
.
Percent
Significance* ( p)
0.87
0.83
+17.0
0.0
Accommodation
0.81
—14.1
Skin looseness
Vibratory sense (M+ F)
0.70
0.70**
+ 1.6
— 1.4(M), + 24.6(F)
Skin retraction
0.74
Visual acuity
0.69
Hearing loss
0.67
Hand grip (M+ F)
0.67**
N.S. (0.70)
N.S. (1.00)
;
+ 7.3
+ 14.0
+ 7.9
+13.8(M), + 13.8(F)
N.S. (0.11)
N.S. (0.68)
N.S. (0.82)
N.S. (0.90, 0.20)
N.S. (0.59)
N.S. (0.40)
N.S. (0.15, 0.18)
Reaction time (M+ F) (light extinction test)
Systolic blood pressure
0.64**
0.53
— 2.0(M), — 10.5(F)
—11.3
N.S. (0.88, 0.55)
N.S. (0.30)
Cholesterol
0.39
-17.2
N.S. (0.05)
0.99
+ 7.0
N.S. (0.27)
Potassium (M+F)
_
Neuromuscular function (M+ F) (handtally)
Combined scoret
*N.S. — not significant at 3% level.
9008329
O4y**
0.36% *
—14.6(M), + 10.6(F)
+ 3.2(M), +1.1(F)
**r values for males and females averaged.
N.S. (0.17, 0.22)
N.S. (0.85, 0.95)
{Weighted according to r value.