Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 131
Chapter X
THE ANALYSIS OF THE
10.1 The trait. Birthweights were ob-
tained for all infants. However, for the reasons
given in Chapter VI we shall limit our attention
to birthweights obtained on liveborn infants
only. Shortly after the initiation of the study it
became apparent that there was a remarkable
diversity among the practicing midwives in the
apparatus used to weigh newborn infants. Ac-
cordingly, early in 1949 each practicing mid-
wife in the two cities was presented with a
simple, spring type scale; prior to distribution,
all scales were checked for accuracy. Weight
was recorded by the midwives in momme (a
Japanese unit of weight; 1 momme = 3.756
grams) and later converted to grams.
10.2 Tire generic argument for irradiation
eff ects.-Thus far in our consideration of
irradiation effects we have concerned ourselves
with only those induced mutations which would,
presumably, occasion fairly large departures
from the norm among individuals in whom the
gene (s) finds manifestation. There exists in
addition to these classes a much larger group of
induced mutant genes, the so-called "invisibles"
or "detrimentals," which give rise to much more
subtle changes. These mutants, on the average,
reduce the fitness of the organism. This loss of
fitness may take the form of a decrease in the
life span, a reduction in physical vigor, or
similar changes. It seems logical to assume that
in most instances a marked reduction in physical
vigor would be reflected in certain body meas-
urements, among these measurements being the
birthweight of an infant. Such a reduction might
be manifested as a change in the mean value,
an increase in the variance of the measurement,
or both. Accordingly, changes in mean birth-
weight or in the variance of the weights of
newborn infants associated with parental ex-
nosure could be interpreted as evidence for
irradiation-induced genetic damage. It should
be pointed out that radiation-induced genetic
1
. .
131
BIRTHWEIGHT DATA
changes in birthweight would, of course, be a
function of the extent to which variation in
birthweight is under genetic control. The avail-
able evidence (Robson, 1955; Morton, 1955)
suggests that the component of variation ascrib-
able to heredity is small. However, this does
not vitiate attempts to determine the effect of
irradiation-induced mutations on birthweight.
10.3 Concomitant variables known to affect
birthweight. A host of variables are known
to, or thought to, influence birthweight. The
most important ones, seemingly, are maternal
age and parity (inter alla, Karn and Penrose,
1951 ), and maternal nutrition and economic
status (inter alla, Millis, 1952~. A word or two
regarding these variables seems appropriate.
Maternal nutrition and economic status may
be considered simultaneously for our purposes
since it seems quite possible that the effect of
the latter is due largely to the former. While it
seems axiomatic that maternal nutrition is im-
portant in birthweight, the amount of variation
in birthweights attributable to maternal nutri-
tion under various circumstances is not ac-
curately known. However, there exists evidence
(Antonov, 1947, and Smith, 1947) that, bar-
ring a totally inadequate diet, maternal nutrition
has relatively little effect on body size. It is in
the area of marked decrease (near starvation
levels) that maternal nutrition seems most im-
portant. Unfortunately, maternal nutrition is a
variable extremely difficult to measure even
under the best of circumstances, and nigh im-
possible under the conditions in which the
present study was conducted. That conditions
in postwar Japan may have been such as to
produce maternal nutritional deficiencies cannot
be gainsaid. However, there is no evidence to
suggest that during the course of this study nu-
trition was at near starvation levels for an ap-
preciable number of mothers. At no time during
the period 1947-1953 was the daily caloric
OCR for page 132
132
intake assured by the rationing system less than
1,775 calories per day. The average caloric in-
take for adults during the period 1947-1953,
as recorded by the Public Health Section of the
Hiroshima municipal government, was
Calories
i947 i,775
948 1,900
949 1,912
950 1,995
1951 2,027
1952 2,050
1953 2,073
This "official" intake was undoubtedly
mented, but to an extent impossible to deter-
mine, by unofficial ("black-market") foodstuffs.
Moreover, the minimal caloric intake available
for women Eve months or more pregnant was
augmented by approximately 240 calories (70
gms.) of rice. Caloric intake is, admittedly, but
one facet of the appraisal of the adequacy of
maternal nutrition, but in the absence of more
specific information it is the only yardstick by
which we can appraise the diets of the mothers
involved in this study. Conceivably, some meas-
ure of the possible effect of maternal nutrition
could be gained by an inspection of the data
available on economic status of the parents in-
volved in this study, or, in view of the gradual
betterment of the diet during the internal of
this study, an analysis of year of birth effects
might be informative. From the standpoint of
the present analysis, it is important to recognize
that while the diet of the pregnant Japanese
woman may by Western standards have been
sub-optimal during a portion of this study,
there is no reason to believe that there were
dietary differences with respect to radiation
categories.
Maternal age and parity are variables more
readily measured than maternal nutrition and
economic status. Their importance is amply
attested to by, for example, Karn and Penrose's
finding (1951) that as much as a full pound
difference may exist between first- and seventh-
born children. Moreover, they have shown that
maternal age exerts an effect not explicable in
terms of the correlation between maternal age
and parity. More recently, Millis and Seng
(1954), studying infants born in Singapore
during the period 1950 to 1951, have extended
Karn and Penrose's findings. These workers
limited their attention to normal, non-prema-
ture, liveborn infants. In two of these respects
Millis and Seng's data are not unlike the data
Genetic EJects of Atomic Bombs Chapter X
here presented. Millis and Seng find that (a)
parity has a positive effect, and (b) maternal
age a slight negative effect on birthweight.
These are findings essentially similar to Karn
and Penrose's. Millis and Seng have, however,
proceeded one step further, and find that the
relationship of parity to birthweight, for fixed
maternal age, is cunilinear and fairly consistent
over differing age groups. On the other hand,
the relationship of maternal age to birthweight,
for fixed parity, is neither consistent nor simply
stated.
In our data, we find that taken conjointly
aug- maternal age and parity can be related, fairly
consistently, to birthweight by a regression of
the form:
where
y=m+~iX+~2w+53z
y = birthweight
m = mean birthweight
x = parity
w = parity squared
z= maternal age
and Id, [2, and be are, respectively, the regres-
sion coefficients associated with parity, parity-
squared, and maternal age.
Since our interests here are limited to remov-
ing the effects of concomitant variation in ma-
ternal age and parity, a detailed presentation
of the relationship of these variables to birth-
weight in Japanese children will be presented
elsewhere. To afford the reader some measure
of this relationship Figures 10.1-10.2 are
presented.
10.4 The dala and their analysis. The ex-
tent of the data on the birthweights, and the
complexity of the problem posed by their analy-
sis, precludes presentation of the raw data in de-
tail. It is hoped, however, that the presentation
of these data will be sufficiently complete to
illustrate the argument underlying the analysis.
In Table 10.1 are presented the mean birth-
weights in decagrams unadjusted for maternal
age and parity and the number of observations
on which these means are based for each of the
64 sex-city-mother-father cells. In Table 10.2
are given the results of two analyses of variance
seeking to determine whether there exist signifi-
cant differences among these means prior to
adjustment for maternal age and parity differ-
ences. The two analyses differ only with respect
to the inclusion or exclusion of the category 1
parents. A perusal of the analysis reveals little
OCR for page 133
The Analysis of the
in the way of significant differences in mean
birthweight between parental exposure cate-
gories. The large number of significant inter-
actions when the category 1 parents are included
attests to the heterogeneity of the data, and
vitiates attempts at generalizing with respect
to parental exposure. In this connection, it is
interesting to note that when these parents,
that is, the category 1 parents, are excluded,
the bulk of the heterogeneity disappears (see
Table 1o.2b). This preliminary analysis of the
data does not suggest the existence of large dif-
ferences in mean birthweight induced by paren
320t
3'Si
3.0f
30s
MEAN BlRrHWElGHT
(DECAGRAMS) 3~
29s
290
285
280
Birthweight Data 133
Hiroshima, and then indicating where the four
city-sex cells agree or disagree.
In an analysis of these data, we are interested
in obtaining answers to the following questions:
1. Is the regression of birthweight on maternal
age and parity significant?
2. Are the regressions based on the individual
mother-father exposure cells within a given
city-sex cell homogeneous?
3. Assuming a significant regression, do the
adjusted means differ significantly among pa-
rental exposures ?
4. Does there exist significant heterogeneity
among the variances in the mother-father cells ?
~ ,-- ~
/," "\ 30,
,, `.
','
,
310
30o .
MEAN BIRTHWEI - T
MATERNAL AGE (DECAGRAMS)
ALL AGES 290
__. AGE 30
PARITY
FIGURE 10.1 The distribution of mean birth-
weight in decagrams by parity for all maternal ages,
and for maternal age 30 only.
tat exposure. It seemed pointless, however, to
pursue the meaning of the interactions and main
effects until adequate compensation had been
made for the concomitant variables known to
differ among the city-exposure cells. Before we
consider the effects of concomitant variables,
the reader's attention is called to Table 10.3
which presents the residual mean squares (esti-
mated variances) by parental exposure weighted
for sex and city differences. The heterogeneity
is apparent on inspection.
In the analysis in which concomitant variation
was to be accounted for, the data were parti-
tioned into four parts corresponding to the four
possible sex-city cells, namely, males-Hiroshima,
females-Hiroshima, males-Nagasaki, and fe-
males-Nagasaki. The results of the analysis of
these four city-sex cells are presented in Tables
10.4 to 10.24. To present the analytical argu-
ment, we shall content ourselves with examining
in detail a single city-sex cell, namely, males
28S
28D
~ ~ -
LEGEND ~
A. ~._~ . ~
Y 202112324~2621 303233 31,4'
2
- 20 21-23 24-26 2729 3~32 33-35 36~8 39-41 42~44
I~ATERNAL AGE
FIGURE 10.2 The distribution of mean birth-
weight in decagrams by maternal age for fixed
parities (parities 1 and 4~.
5. How heterogeneous are the observations
within a mother-father cell ?
6. Assuming the answer to question (5 ) is
"appreciable," what are the variables which may
account for the within-cell heterogeneity?
These questions have been posed in the order
in which we shall treat them in the following
paragraphs.
In Table 10.4 are given the results of the
analysis of covariance leading to the determina-
tion of the regression coefficients b,, t2, and b3
associated with parity (x), parity squared (w),
and maternal age (z) for each of the individual
mother-father cells within the males-lIiroshima
cell as well as the estimates of b', t2, md b3
based on the pool of the exposure cells. From
~ By "pool" we refer to the results obtained when
we sum the sums of squares and cross products of de-
viations over all 16 exposure cells, and estimate the
regression coefficients therefrom. By "sum" we refer
to the results obtained when a regression is fitted to
each of the individual exposure cells.
OCR for page 134
134 Genetic Ejects of Atomic Bombs Chapter X
-
c~
1
._
~of
Z
z
~ _
cn vet
~ cat
u,
0 at.
P4
.c
-;
<: ad
Ed
z ~
x
-
04 ~
_ sat
EN ~
~ _
m ~
z
at:
-
cn
.
cot
_ Go ~ ~ ~ ~ 0 ~ 0
it ~ ~ ~ ~ 00up vie ~ 0
^ · ~7 ~\ ·c<~ ·
cO
oo ~ 0 ~ ~ rid cry vie
I ~ ~ 0 ~ ~ ~4 so O vie
~ ~ ~ a' oo ~
~ _1
cry
0 ~ ~ 0 0 ~ ~cry 00
By. ~ lo. ~ ~ ~ ~ ~ so.
~ ~v,
~ ~cry
00 ~ ~ ¢\0 oo ~ ~up vie
oo~ ~ u ~ \0
0 ', O" ~4~ ~O ~ ~i
~^ ~ ~ ~ ~c~
v,
c~
o~
r~ u~ ~ C;~ ~ ~O
oo ~u~ Gs ~ ~r~ ~ ~
- ^ ~i~ 0 ~ ~ O v~ _,
~4
', ~ ~
'X ~ IX ~ IX ~ 'X ~ IX
-
Ct
1 ~
~r 0
s~auL~o~
r -~ -- -- -~ -^
_ _, ~ _4 ~ _4 ~ v~ ~G~ r~
o ~ ~ GN ~ ~o (-i I_ · -^ ~
0 -
. ~ O ~ ~ ~ ~ ~ 00 V~ 00
00 ~ ~ 00
° ~ O 'r' ° ~ O
C~
u~ O ~ ~ ~ CO ~G~ ~
G ~d4 ~ cO ~ ~ 00 00
C~ _4 _1 ~ ~ ~ · ~ _i
C~ ~ O ~ O
~ ~ oo ~ = - oo ~> - 1
GN V~ ~ ~ O a ~ c ~cd
°O ~d4 ~ ~ ~ u^'
~ ~ ~ ~ _. ._
~ ~ ~m0
.=
G~ V~ r~ ~ u~ ~ v~
\0 G~ ~ ~ C~ v~
~_I ~ ~O O ~ ~m_l
00 ~ ~ ~ ~ 1
C~
Slaq~ow
_ V~ oo
~d
-~^o
- - o'
I =~ ~ °
e~t' ',-°x
oo
U~ ~ ~o
cr, '`.
oo
C~
o
N
00 00
O~ O
C~ \0-~ ~
_~ OO
O t_ ~
O
· ~ ~ ~
~^0 ~ OO
Io
-
g
I
~ u~
v~
~ ~ oo
..
ooo
~ G~
v~ ~
o
I ~,
U~ o
o
I~ CC
C~ ~
o
-
o
oo C~
o o ~
<.
o ~ o
~ 'X ~ 1x ~ IX ~ IX ~ IX
C~
1
~,
S]~]O~
0 ~r~ oo 0 cO oo oo v~ \0
ed ~ ~ O ~ v~ G ~ ~ u~
o ~ ~ ~ ~ U~ c ~r_ o~ c,r,
mo C~= ~ o o ~o
U~ ~oo ~V~ o oo ~ ~
~ o o o ~o
C ~C ~C~
I_ ~ ~ ~ ~1 1
oo 0 ~00 1
c~,~ c,\ ~ ~ 1 ~
OO O GN 1 0
~ ~ 1
1 ~ ~-
~ 1 ~ -
G~ 1 ~ ~
G~ 1 ~ o
1
cN ~d4 ~ ~ ~1 1 0
C;\ 00 ~ GN C~ ~1 ~1 - . 1 cx c~
ax ~ ~ (- ~o~ r ~o 1 G~
I_ o ~i o ~ O ° 1 ~ o
~c ~ 1
s]~lon
J
OCR for page 135
The Analysis of the Birthweigh' Data 135
TABLE 10.2 ANALYSIS OF VARIANCE OF BIRTHWEIGHT BY PARENTAL EXPOSURE AND CITY
(Unrelated parents)
a. All exposure categories (4 X 4)
Sum of squares
Sourceof deviations DFMean square
Main effects
Cities (C) 675.79 1 675.7922.640
Sexes (S) 1,070,650.05 1 1,070,650.049600.077
Fathers (F) 14,154.42 3 4,718.1412.644
Mothers (M) 4,346.49 3 1,448.8311.231
Interactions, first order
CS 51.98 1 51.98134.324
CF 12,253.02 3 4,084.3402.289
C M 20,235.97 3 6,745.3233.781
SF 289.84 3 96.61318.467
SM 54,757.96 3 18,252.65210.230
M F 39,647.35 9 4,405.2612.469
Higher orders 19,162.58 33 580.6843.073
Between 1,235,883.20 63 19,617.19410.995
Within 112,097,004.72 62,828 1,784.189
Total 113,332,887.92 62,891
b. Excluding parents with exposure 1 (3 X 3)
Sum of squares
Source of deviations
Main effects
Cities (C)
Sexes ( S )
Fathers (F)
Mothers (M)
Interactions, first order
CS
CF
CM
SF
SM
MF
9.64
114,255.51
....... 2,940.19
5,698.70
DF Mean square
1
2
2
.37 1
8,149.72 2
15,069.70 2
2,018.93 2
8,825.61 2
6,995.23 4
9.638
114,255.511
1,470.096
2,849.350
207.725
57.072**
1.362
1.423
.3695,425.377*
4,074.8612.035
7,534.8523.764*
1,009.4641.983
4,412.8072.204
1,748.8071.145
Higher orders -16
Between 190,786.4935 5,451.043 2.723**
Within 17,597,261.258,790 2,001.964
~-
Total 17,788,047.74 8,825 -
OCR for page 136
136 Geodetic Ejects of Atomic Bombs Chapter X
cx
O
00 ~ ~ - =
_ _ ~ ~ ~ ~ ~ NO ~ ~ O
. . . . . . . . . . . . . . . .
1 1 ~1 1 1 1 ~1 1~
O ~ ~ ~ O cur ~ cat
= - ~ ~ ~ ~ O
~ 00 ~ ~ 00
. . . . . . . .
1 1 1 1 1~-
5
cat ~ 0 red ~
~ Get Cx 00 ~ ~ ~ O
0 - ~ ~ O O ~ Cx
~ ~ AN 00 ~ ~ ~ ~
. . . . . . . .
~ 1 1~ 1 1
ON ~ Cut ~ Cx red oo oo ~ red 0 oo
G~ O \0 ~ G~ ~ (;N ~ ~ O x0 ~v~
c~ 1-~ r~ ~ 1- ~ ~ O C~ O
a~ 0 ~ ~ ~ r~ ~ ~ ~ ~ ~
0 0 ~l ~- c~ ~ ~i ~ O ~ ~-~ 1 Cx
~, ~ ~ 1 1
V~ ~ ~ ~ ~ O C~ O ~ ~ ~ ~ ~ ~ ~ C`6
iN O ~ ~ ~ ^ = a~ G~ oo ~ ~ ~
. . . . . . . . . . . . . . . .
V~ ~ O ~ ~ ~ ~ ~ ~ ~ ~ ~ oo O oo
00 ~D ~ ~ ~ ~ ~ ~ ~ Cx ~ ~ r~ CN
~ O ~ ~ ~ ~ - = ~ ~ ~ ~ ~ ~ O ~
W -~= ~ =~r ~ 0-~= u-~ r-~-(~,
v~ 0 ~ ~ r~ ~ x 0 r~ 0 ~ G~ ~- ~ ~ oo
~ ~ C~ 00 ~ ~ ~ ~ ~ ~ ~ ~ ~ -
V~ ~ ~ _`
O
n
~3
~ 0
ZE--.
-
~: ~ ~ ~ ·- c
.L4 ~ ~ · _
~ ~ o ~ ~
·~
-~=
~: cy . ~ ~ ·
r~ ~ ~ 0,()
o o~.=
~ [=, ~ ~
E ~_
1
GC
v~
o
cx
v~ ~ ~ 0-= ~ r~ ~ ~ N~ r~ Cx~ c~
~ O C~ G~ oo ~ O ~ ~ ~ ~ ~ ~ ~ ~ 00 00
3 x t~, ~ <~3 ~ ·~ 00 c~, ~ ~ O O 0 ~4 ~ ~ v~\ O
~W ~ ~ 0~= - ~ - ~ ~ - = ^=
O ~ ~ ^~40~0 ~ ~ ~r~
~:
` ~ ~ > C~ Cx '` ~ cc r~ co
^-0 ~-~ 0 Cx~ r~= =- o ~V~
r ~ ~ ~ ~ ~ 0O-OO~,O~=OO=~=O=~^ -=
~ G~_ ~ ~ O ~ ~ ~-1 r~;r ~ ~ c;xo ~ ^^ - ~ - r~ ~ =~= ~ ~ ~U
j ~ o~ ,^ ~ ~ x X ~ _, ~ ~ ~ ~ ~ ~ ~ ~ ° ~ ~ ~ 1 1 1 ~ =
,_ mo r_ 0 c~ ~ ~o~o~ ~ 0 c~a)= oo ~ >-c
~ ~o ~ O ~ ~ c4 ~ ~ ~ 0 ~ r~ r~ ~ ~ .
U ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ . . . . . .
oo oo '` ~x Cx c~ ~ GN~ CC ~ 00 ~ ~ ~ ~ ~ ~ ~- ~ D,,C
· _ . o ~. ^ ~ ~W ~ +^ ~ O. ~ O ~ ~ ~ ~ ~d4 ~ Cx ~P c<~ O q
X \0 C<~ oo GN ~O (~l ~ it N
CN ~ ~ ~ ~ ~-~ ~ ~ ~ O ~ ~ ~ O
1 -I O 00 ~4 ~ ~ CO O Cx C~= \0 C~ 1-X 1-~0
~ ~m ~ ~ ~ ~ g O oOo ~ ~ ~ ~ ~ ~, ~ ~ g o ~
^^ ~ ~ 0 ~ ~w ~ ~ ~ ~ ~ ~ ~ O. ~ ~ ~ ~ O
c< ~ _~ ~ (~ 0 ~ ~ v~ O ~ ~00~ 00
~, ~ I_ ~ oo r~ O [L CN \0 ~-~ ~a
r~ ~oo u~\ ~ _ co _ *
^_ ^_ ^ ^ * z O O =~0 ,`= ~v~= 00 ~ O cx~ ~
~d4 '< cc ~ V~ Cx Cx _~ oo ~ 1-~ ~ C~ ~ ~ 1_ ~O
°° :d x ~ ~ ~ oo ~ ~ ~ ~ ~ ~ ~ cx oo v~ l- I_
. ~ ° ~ C~ ~ ~ °° ~W tr~ 0 trN (°~ ° O ~ ~ ~ ~ ~! c~ ° ~^ (~ oo C°
V~ o~ ~ - ^ ~ r- ~ <} 11 (-)
I ~ r- - ~~- ~ ~ X ° CtN ON ~~ 00 ~ ~ Cx 0 v~ ~ O ~- <) ~ ~ ~Oo
-~ ~c~ ~ mo~-oov~a~V-~-oo~
c ~V~
1 ~ ~ ~ ~ ce ~ G~ ~ ~ \0 =~-Cx 00^ ~ ~o c~
, ~r~ ~ ~ ~r '~ ~ ~ ^= ~ ~ ~ ~ ~ 3
~r ~ ~ ~ ~o ~ ~ ~°
% GN ~ . _
4 ~ ~ ~d4 ~ ~ ~ 4 ~- N ~ ~ ~_~ D ~
== mo~-xr c~ ~ o~ 0 - = ~ 11 11
~N ~ ~_ o r_ O -I Cx ~ ~P r~ ~ ~ ~I_
0 3 '` ~ ~, ~ ~ ~> ~ :` x
_ r' ~ r~ ~c~ 0 0~= 0 r`= 0 a,= 0 ~
oo ~ ~ 0 ~ c~ ~ c~ ~ ~ ~ ~ ~ ~ ~ c~
_4
m
_ ~ ~ ~ ~ c~ ~ ~ ~ ~ cx c~ ~ ,_
c~ ~ c~= oo ~0 ~r r~ ~ ~ I-~ Cs ~ ~ r~
x O =\ ~ ~ ~ ~ 00 ~ ,~ ~ v~ ~ ~ O ~ O
3 ~ ~ ~ ~ ~ ~ c~ 0 ~ c~ ~o ~ ~ 0 ~ a'
oo ~ r~ ~ ~o ~ O ~ ~ ~ ~ ~ ~ r~ 0 G~
oo ~ ~ co 0 ~ - . ~ ~ ~ 0 ~4 C4 ~ ~ ~ u~
~r _4 ~ ~ ~ c~
r~ V~ V~ ~ Cx~ ~ cc C~ ~ ~ ~ a
v~ ~ ~ 0 ~ ~ ~ ~ c~ cx ~ cx ~ ~ c~
~ ~ ~ ~ cx ~ ~ ~ ~ I- V:) ~ V) -~ CS ~ cx
3 ~, ~ ~ ~ ~ c~ =, a~ ~ ~ cc ~ ~ ~ ~ ~ 0
W =^~^ ~ c~ l-~ ~ 0 ~o 0 0 ~o cc ~-
~ ~ oo ~ r~ cx ~o
_· ~ _ ~c ~ v~
_I
v~ ~ _
r~ ~ ~o
~ ~ ~ 0 ~
_
== ^0= ~ CN' ~ ~11
~ Cx ~ O C~ G~ ~ ~ C~ ~ ~- ~
· I_ oo ~ ~ ~ ~ ~-~ ~ ~^
aw
v~
~4
~ ~ ~ I
OCR for page 137
The Analysis of the Birthweight Data 137
Table 10.5a we note that the estimates of b,,
t2, and be based on the pool remove a significant
amount of variation from the birthweights. In
the light of the work of other investigators this
is not an unexpected finding. However, if we
return to Table 10.4, we note on inspection
considerable heterogeneity among the b's asso-
ciated with the various exposure cells. That
this variation is significant is borne out by
Table 1o.5b.
At this point, it is of interest to inquire into
the amount of variation in the birthweights ac-
counted for by variation in the individual re-
gressions after removing the portion associated
with the common regression (see Sec. 6.3~.
From the data in Table 10.5, we form the mean
anticipated from irradiation, variation, account-
able for on other grounds, of as small as 3 per
cent could be sufficient to obfuscate irradiation
differences.
For the analysis of variance on the adjusted
data set out in Table 10.6, adjustment was to
the common regression because adjustment to
the individual exposure cell regressions removed
a seemingly negligible additional amount of
variation (for a discussion of the computational
procedure see Wishart, 1950~. For the reader
not familiar with covariance analysis it might
be pointed out that the computations in Table
10.6 effectively transform through the pooled
regression the observed array of exposure cell
means into the array of exposure cell means
TABLE 10.5 TESTS OF THE SIGNIFICANCE AND HOMOGENEITY OF THE REGRESSIONS OF BIRTHWEIGHT ON
MATERNAL AGE AND PARITY: MALES, HIROSHIMA
(a) Test of the significance of the regression based on within-cells (pooled) regression coefficients
Source SS DF
Variation removed by regression 761,262.72
Residual within cells (pool) 28,264,084.66 16,178
MS F
2 253,754.240 145.246* *
1,747.069
(b) Test of the homogeneity of the regressions (all exposure cells considered)
Source SS
Differences in regressions 116,630.11 45
Residual within cells (sum) ....... 28,147,454.55 16,133
MS F
2,591.780 1.485 *
1,744.713
(c) Test of the homogeneity of the regressions (only those cells in which both parents were exposed are
considered
Source SS
Difference in regressions 38,429.76
Residual within cells (sum)3,473,234.85
square ratio of the "mean square residual
(pool ) " to the "mean square residual (sum) ."
The value obtained is 1.001350. Accordingly,
we may assert that the variation in regressions
accounts for 0.14 per cent of the variation in
birthweight not accounted for by the common
regression. This value obviously attains per-
spective only if we know the amount of varia-
tion in birthweight accounted for by the com-
mon regression. The latter we obtain from the
mean square ratio
28264084.66+ 761262.72
16181 (1747.069)
which is 1.02674. The common regression, then,
accounts for 2.7 per cent of the variation in y.
It is natural to inquire here whether this amount,
2.7 per cent, is of importance. To this we can
only answer that in view of the small eRects
DF MS F
24 1,601.240 1.124
1,929 1,800.536
which one would obtain if each exposure cell
had the same maternal age and parity distribu-
tion. The mean squares obtained following this
transformation are wholly analogous to those
obtained in a simple analysis of variance, and
may be interpreted in the same sense. Inspection
of this table fails to reveal significant differences
among maternal or paternal exposure categories
or evidence from the interaction mean square of
nonadditive effects of parental exposure. The
adjusted birthweight means are given in Table
10.7.
The next question to be asked of these data
was, "Does there exist significant heterogeneity
among the variances in the mother-father cells ?"
The residual mean squares for the sixteen ex-
posure cells within males-Hiroshima are given
in Table 10.8. Bartlett's test (cf. Rao, 1952)
of the heterogeneity of the variances is not
OCR for page 138
138
Genetic Effects of Atomic Bombs Chapter X
vat ~ ~_
[~=,°` ox ~ 1 1 1 1 1
vat x in 0 rat
¢~^ cat ~ O
~ 0 ~ ~ x l_
65!~ X ~ ~1 1 1 1 ~
cat X 0 ran 0
~ ~.
ret
4J
cat ~ ~0
R ~ rat I I I I ~
I_ 7 c',
on 1-A\ C;x
At; ~ ~ ~ 1 1 1 1 1 8 ~O ~ ~ ~ ~
Q ~ ~ ~ ~ ~ o ~ ~ o ~oo ~ ~ °
X ~ c,\ - To , ~ ~ · · · · ~ma, ,, ~ .
~ ~ ~ o o
~ ~x-= ,a ~ -~- ~-~- ~
on ~ ~ ~ ~ = - Cal
O ~ X O no ~ to 0,)
7 1 1 1 1 ~ ~ ~ red TO To
=^ = X X x a = 0-~ ~<~- ~. ~ <,
.< .- ~ ~ ~ oo r ~ ~ ~ ~ c
1~,- _ C~ ~ O ~ ~ C~
~ ~ O _ 11 I! ~ ~ ~ ~ ~ ~ ~._ ·_
D I | | | ~~^ - - ~ A
~ ~ \0 ~ \0
~-~- ~11 11 11
x cx v~ ~r ~ ~ ~ ~ ~ ~ ~ ~ ~X
~o ~ O ~ v~ oo ~CO r<~ ~ v ~ ~ l~ v~
~ ~ ~ x ~ ~ ~ ~ 0^^ ~ a ~ ~ 00 ~ ~ ~ Oo
O O O 0 - 0 ~10 ~ ~ ~O O O O
mc`~= ¢ 1 1
r~ ~ ~ r~
~ O ~ 00 ~ ON ~ ~ ~
. ~O ~-~ CO ~ ~ +0 -
~ O ~ ~ oo ~ O4 r<\ 1-CO
~ ^^^ ^^ ^^~
~_~ cO _~ v~ r- ~ 00 0 oO
a
- \0-X ~ r~r~ ~
m ~ ~ ~ ~ -~, ~ ~ ~ ~
~ ^0= ^^ ~ 0~~ r ~
~ w ~- o^m o^~~o== 8 B ~ ~ ~ ~ | I
- ~Cx ~CN Ov~1- - 0,0 ~ O
x ~ ~ ~ O X ~ oo td {~3 ~T~
9 x - ~ ~ ~= ~ ^ - ~ v ~
w -~ ~ ~ ~ ~ ~ ~ ~c
~ _. _ _ _ .2
X ~ ~o oo G~ ~v~
E ~ o ~ c~ 0 oo ~ 0 ~o ~ ~ ~ ~ ~ ~ ~O
~ ^~0 -~= ~a - ~0OO~= ~
z N ~ oo ~ ~ ~ ~ 1- ·~ ~0 1 1 ~ · · · · C~
t)
Z ~ ~ ~ X ~ ~ ^
~x ~ ~ o ~ a~ r~ r~
- W ~ ~ m. ~ ~ c;` ~ ~ r~ ¢\ ~
_ c~ C7~ ~ 0\ - 0 C ~; X ~ O
C~
~ x~xo r~ a)-
O ~a'c~x~ ~0 _ ·<
~ 0 ~ O ~ ~ _
~A ~ ~ ~ ~ ~ ~_
- W ¢\ ~ C~ -~ ~ c~ ~.o {~.
t.A, _ ~ 0 ~ ~ - ~
o~ ~C` ~r.1 ~ ~ oo
'_] oo
r~ o ~ v~ r~ ~ c~ l- ~
3~ ~ ~ ~ ~ ~ om ~ ~ ~¢ ~ ~ ~ ~
W ~ ~?- ·<~ ~ ~-` O~ I_ ~
~Ci~ ~ ~ ~ CN ~ ~ ~a'
o ~....
~ ~ ~ ~ ~ ~ o ~ C" uA, . . . .
er1 K ~ a) ~ ~ v~ ~ 0 ~ ~ O
,_1 ~ ~ ~ ~ O 0 0\ o0 S L4
W ~ X ~ \0 Cx ~ ~ 0^ ON
~A, · .
^~4 · ~Y
~ ~ oo~ 0_ ~ c;` ~t ~
~o~o ~ ~_ ~ _ I_ ,=
N~ ~ o~ o~ ~ ~ o ~ -~ N c~
~^ ^ ^^ ^^ ^ ^ ^ Ct
W ~ ~ ~ ~ ~ O
-' \0 V~
r~
.
.
.
.
.
.
.
. - ~
O
·~ ·_
O '~ ~ ~ ~ ~ ~ ~ ~
."
' R~
~C. -
· D
· 11 11
: ^x
1 1
v~ ~\ c~ ~
IOl o O O
~ c~ ~o
C~ ~\ Gs
cx _ ~ r~
I 00 G~ cr ~v~
r~ ~0
o
oo oo
aN U~
r~ ~ 00
oo
Io oo
o ~ ~V~
·~, ~ G ~-
o ~ o
· - . .
~A. · . .
o
· - . .
X · . . .
a' · . .
~V~
=:::: +
o
4
| l~e t) IN
~ 1 1 1
- x B N
1 ___
11 11 11
a
1
x
1
._
,^
cr, G~
o.
. ~ ~,~ Ol O
11 11 11
c ~ ~ ~
OCR for page 139
OCR for page 140
OCR for page 141
OCR for page 142
OCR for page 143
OCR for page 144
OCR for page 145
OCR for page 146
OCR for page 147
OCR for page 148
OCR for page 149
OCR for page 150
Representative terms from entire chapter:
mean squares
The Analysis of the Birth weigh Data 139
significant. Thus when all exposure cells within
the males-Hiroshima cell are considered, the
only evidence for an association of birthweight
with parental exposure is the heterogeneity of
the individual cell regressions. But, this associa-
tion is neither consistent nor does it persist to
a significant extent when the category 1 parents
are excluded (see Table 10.5c).
Before we summarize and consider the possi-
ble interpretations of the findings on the males-
Hiroshima data let us turn to the remaining
three sex-city cells. Tables corresponding to
those for males-Hiroshima are given for fe-
males-lIiroshima (Tables 10.9-10.13), males
TABLE 10.8 THE RESIDUAL MEAN SQUARES FROM
THE INDIVIDUAL CELL REGRESSIONS:
MALES, HIROSHIMA
(The degrees of freedom are given in parentheses.)
Mothers
1 2
1 J1,747.87 1,649.29
)(8,669) (2,711)
2 {1,777.14 1,783.05
=O ~ (740) (894)
5 311,849.41 1,957.12
~ (291) (186)
4_512,382.73 1,968.26
~ (195) (110)
Bartlett's test for between-cell
mean squares:
%2_ 20.43
3 4-5
1,768.00 1,595.93
(1,061) (537)
1,738.38 1,876.84
(215) (104)
1,798.85 1,764.54
(252) (44)
1,598.47 1,609.30
(73) (51)
heterogeneity of
DF 15
Bartlett's test for between-cell heterogeneity of mean
squares when category 1 parents are excluded:
%2 2.12 DF 8
Nagasaki (Tables 10.14-10.18) and females
Nagasaki (Tables 10.19-10.23~. In none of
these three sex-city cells does the analysis of
variance on the adjusted data reveal significant
differences as regards mean birthweight between
maternal or paternal exposure categories or evi
dence of heterogeneity as judged by the interac
tions. In Table 10.24 are set out the principal
findings with regard to the four sex-city cells.
From this table when all exposure cells are
considered we note (a) significant heterogeneity
in the individual father-mother regressions in
two of the four sex-city cells, (b) a reasonable
measure of constancy in the amount of variation
removed by the common regression in each sex
city cell, and (c) significant heterogeneity be
tween the residual mean squares within a sex
_~ 0 ^m coo ^~m arm om
O ~ 0 ~ O 00 ~ ~ O _ ,_ ~ ~ x
~ ~ m^~m ~ ^m ~ - _ m=m
D~ o ~ in ~4 ~ ~ ~ ~ So ~ lo O _.
. . . . . . . . . . . . . . . .
1 1 1 1 1 1 1- 1- 1 1
Vat
Cut
1
so ~ ~ to ~ ~ O Vet ~ ~ ~ ~ ~ ~ ~ X O
oo (X\ ~ m ~ ~ ~ C:x ~ ~ Go- ~C4
^' ~ ~ Cat- ~ -~ Cat Go O X
x ~ ~ ~ ~ ~ ~ 0 ret ~ ~ ~ ~ 0 0 ~so
................
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
_ ~ _ ONE ~ ~ ~ vet ~ = - O red cat cat
O ran ~ Cat \0 ~ O ~ O ~ ~ ~ ~ _ ~ Cx
~0 ~ a ~ Van ~ Van ~ O O ~ ~ Cal _ I_ Van
_ X C; ~ ~ ~-I O tm Cx 1_ ~ X ~-~4
O \0 1-X ~ ~ of red ~ oN no (~ ~ (~ A -
~ _ _ ~ ~4
A:
-
o
~0
CC
O Van ~-\0 CN ~ ~- ~ ~ Cx ~ ~ Vet red
O X ~ ~ ~ Van O O WE \0 ~ Cx ~ X ~ O _
van -~ X X Hi ~ 1- Cx ~ Van ~ X ~ ret X O Ox
m~ X\O ~ O red _ ~ _ _ JO van -
~ - - - -~ - m=~0 00 =~0=
Or No ~ ~ _ rut ~-O ret ~ ret O rat ~ ~ Cut
van ~ X ~ ~ vet vet ~ vet ~ so ~ ~ van I_
X ~ X _ v- - ~ ~ ~ ~ ~ _ _ _
~ ~ _ _ _
0 ~ ~ ~ vet ~ ~ red ~ ~ cat 0 0 ~ ~ O
so or-~ ~ ~ ~ vet vet ~ O O ~ ~ _
. . . . . . . . . . . . . . .
X ~ x~ OX ~ O +~= 00 ~ - ~ was - ~1-
to Van ¢~+r~ X ~- cut O ~ O ~ l_- ~O
W ~ --~ cO-~~ -vet ~ X no no ~00
-~ ~ row- _ _
_
^ co X or ~ ~ no rot Cat O X O O O ~ 1-red
can ~ ~ red ~ 0 ~ X rut x ~ _ 0 0 _ ~ 0
....... ------.-.
, 1 lo. Ore 0 r` - ~ ^~= - ~ ooze
N ~ Ad
o
o
:^
3
W
¢
of;
N
By. B
0 W
B
W
a
cat ~ ~ ~ ~ ~ ~ 0 0 Van ~ or ~ _ 0
co so ~ m
. . . . . . . . · . . · . . . .
oo co ~ ~ red ~ red ~ ~ US 0 0
of ~ 0 Al-or:) C\~ v~mo 1 ~ ^~m
cut oo ~ 0 cat ~ ~ 0 ~ rat ~ I ~ ~ 0
o ^~ - ~ + - mm 1
_
van ~ r-~ C;` ~ O cut ~ ~ 0` 0 0 1-~ ~
~ ~ Cat ~ ~ O ~ ~ ~ ~ O O O ~ ~ O rut
x ~ oo of ~ ran 0 ~ ~ In so ~ ~ ~ fir t_
of oo 0 _ ~ rut 0 ~ ~cat
W~ ~ ~ ~ ~ ~ ~ ~ ~ ~ so or o. cat ~ 0 _
· . ~ ~ ~ ~ l~ ~ cO ~ ~ 1-~ ~ ~ ~ ~-
~ Vet
0 X 0 ~ Pro ~ ^^o ~ ^~ COO
of ~ ~ 0 ~ 00 ~ ~ No ~ ID 1-~ van _
I_ 0 oo van rot ~ x co co ~ ~ ~ Cow \°
O _ O V-0 Vet - Cot - ^m 0 X ~ ~ Cat
_ ~ ~ ~ ~ ~ ~ ~ ~ ~1 ~ _
~ _ ~ ~
to ~ ~ ~ ~ r`~ ~ 00 ~0 ~ X ~ O
00 C;` ~ ~ ~- ~ ~-beg ~ 1-
_ ~ ~ van 0 ~ ~ ~ ~ ~ _ c4 ~ X ~ O
oo I ram _ cow Fix
00-~ ~ ~ ~-~ ~ ~ 1 - _ \0 ~ red ¢\
rut ~ rut ~ red oo 0 ~ _ ~ Cx ~
t~l Cut W\ A ~ _ ~ rip ~ 1
~ .
X rut ~ oo ~ ~ 0 ~ ~ _ _ 0 0 ~ ~ 0
A Gal ~-_ ~ Van- Van-~ O O ~ CO _
_ ~ _ \0 ~ ~ ~ ~ rO ~ ~ ~ ~ ~ ~
O m~ ~ red-m\0 Cork oo OX Go_ _
-X ~ ~ X ~ ~ OG raw ~ ~ ~ ~ ~ \.0
O ~ _ ~ ~ ~ O van ~ _ A, _ van ~ ~ r
ail I_ A- (~4 ~ ~ _ _
0 _ ~3 x ~ ~ ~ ~ _ ~ Go rut ~ ~ O~C:
^ ~ ~-~ o Go ~ Al o\ O ~ 0 ~ _
O Cx ~ Cut ~ ~ O~ A r~ (~ ~ A 00 00 {~ GO
O red O ~ ~ O ~ ~ rut ~ ~ ~ ~ ~
~ OS 1_ ~ ~ ~ ~ ~ ~ ~ I_ ~ vet ~ Cut \0
_ 1_ van I_ _ _ ~ ~ ~ ~ 00 ~ ~ ~ ~ ~
_ ^_ _
-
1- 0 1` ~ _ ~ Cat O _ ~ ~ vet _ ^
van Cx ~ ~ ~ ~ ~ ~ - Cut _ Cx ~ _ _ _
_ oO ~ ~ 00
!- - ~ _ ~ ~ o0 ~ ~ 1-~ \0 0 ~ ~ ~ ~
P Cuckoo Van_ V-~ +00 Van_ -m COG
. -^ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ .
rat ~= '` A_ rat x mix _ 0 Too oo m"
r~ Cat (~l ~ (~4 ~ r<~ ~ ~ <~\ _ _ _
X O4- ~
-
~ d
A_
Ce4
,~ C
· "4 ~
~ id
me
1111
. ¢~
Cal
ray
Cx
0
_ ~
_ go
\0 . ~ id
D
ox 11 11
AX
ON
CO
Cat
~4
Cot
_
0
cut
O.
rut
OX mm 0~ X CN`O _m Volvo= Deco~
AN ~ ~ rot O ~ ~ Go ~ a) ~ van 1 -- 1-~11 Van
C;\ ~ O Van 1-X - ~ - ~- - 11 Cat
_ Oi _ ~4 ~
~ _
. .. . . .. . . .. . . .
.· . . .
.. . . ..
.. . . ..
. . . . .·
.. . . .
.. . . .
. .· . . .
.. . . .. · . .. . . ·
. . . . . . . . .
' cut vet l ~van van _
Ci' ~ ~ ~ ~ ~ _
Hi ~ ~ ~ ~ I ~ ~ ~ ~ ~ ~ ~ ~ I I I
140
o
_ .
a:
m .0
0 ~
-
-
-
V)
-
._
o
no,
~2
CO
I
c
o
._
Cal
0c
4
o
C
C
=
V'
o 1
z
o
~ C.~
O
Ed
O
- [Z4
Z-
O Z
O PA
Z ~
~ `.Y
z
_
~
Z ~
~ En
_ A:
5!
X
En
o
En
Cal
lo
-
o
-
¢
*
*
\0
~c' 1
Cal
-
C
o
V,
-
in
X
-
-
-
V,
o
._
as
Vet
00
O
I
~ Vat
\0 .O
C
. . o
:: ~
. . O
. .
0 "S
. _ . it,
U) ~
0£ 0 0
D V) ~
~ ~ 7 D
o o.= -
C~ ~ ~
q) .~
~ B
.0 cd
cd ~
-
>=
0 ~
~ 00
V) oo e~
~ o~
G~ 0^
~ O
GN
~° 1
00
V) r~
1
.
G~
~ 0
C~ r~ ~
o^ -
00
v~
- ^
0
:
. _ .~
8 ~ ~
~ ~ o
=7 <,,
o -.5 ~
cn Ces
CJ-¢ °
Ccd ~
~ - ~
Q" ~ ~
Gerzetic Efects of Atomic Bombs Chapter X
O1 1 1 1 1
c
~ ~0
c'' · .
_~ ~ O _
2; x0 _
v~ \0 v~
c~
Q
V~
~ o. 1
~4 V~
. .
C~ oo
oo
~ _1
X
C~
o
x
cn ~ 1 1 1
~:
Gs 00
C~
. .
^+ 1 1 1 1
- ~
~ l l l l o
. .
c~
z¢
E" ~ oo
moo x
¢\
~ oo ~
f~
^ ~ ~ mmm
~ WO ~ C'
~ w
~ xoo ~
z w~=
o
z w
w
· .
~ - 4
c~ - ^
. .
·
v)
o ~
· -
v) ~
~ =, 7
~ c) c
0 ~ ._
cn ~ ~
._ ._
a) ~
c~
Q) ~
I¢: ~
c~
¢
-
-
-
o
-
m ~
¢ w
O ~ r- m
~ ~ O \0 .`
x ~ _.
~ r~
x 00 v~ _,
- - O 00
G~ ~ ·^ ~
0~0 _ O
q. O
~4 ~ O
~.. ~
x
;^ ~ ~ x
^
r~;r ~ ~ ~
~4 ~
Cx'
;~ oO ~ O
W ~ ~ I_
O - =
O oo O
~ _ ~
~X
X 1_ V~
e _d _
P
W ~ ~ ~
Q
V~ ~
o
o
V~
. .
. . .
· · C ·
o
V) ·_ C
C) C
C ~ ~ ~
~ ~ c m ~
. . .
1 1 1 1
c
o
.
1 1 1 1 1 ~
OC
c'
;^
~Q
P
O
~; v
~ O
q)
c
I_ , ~ V4 v)
c~ 00 ~ ~_
O :'
~,
x ~ O ~ c~
~c
\0 0 ~ r~
cx ~ .` O v,
=~ - ~ 1111
r~ C~ '!
O ~ ~ ~
. . . . .
\0 ¢\ v~
~ ~ O ~ O
x ~ m^m
~ 00 ~D ~0
\0 ~ \0 ~ ~
~4
~ cx ~ r~ r~ 0
o~ V~~ r~ 0\
cx
x - -
_ ~ ~ _~ _1
v~ ~ v~ v~ v~
x - - 0 r~
x ~ x
x O 00 0
~ ^ ~ ~ ~ ~
O r~ O
,_
r~ cx ~r
v~ oo ~ a'
v~^
c~
x ~ r~ oo
_
~ c)
r~ oo
\0 ::
~_
00 ~ ~ ~ v, c4
c
_` ~ ~
c,
. ~
~ CN CN k0 td ~
=~ - c`E
o-~~ 11 11
~o ~ ~o
~ P
o ~ mo
Cs C~ V~
A _ ~ _
~0 ~ V~ V~
C~
X
X
V~ Cs V~ ^-
~ _ _ _ ~_
Ox \0
0 \0 ~ C~
\0 1-~0
C~^ ~ +~0 Cx
X ~ ~ -
~4 X ~-\0
~ V~ ~ ~ ~ V~
O ~ c4 0 ~ ~-
X ~ V~ _'
O ~ ~ r~ ~
X =~ 00
_4 r~ 00 C~ ~ C~
O ~ O ~ O
Cx
~ O O ~
O O O O
~^ ~
V~
_I
. .
. .
. .
. .
m~_
++~+
~c
0£
.
B ;^
, ~ ~
~ . _
· - C~
1111
:^ X
The Analysis of the Birthweight Data
TABLE 10.12 THE ADJUSTED BIRTHWEIGHT MEANS: FEMALES, HIROSHIMA
x w z Ax Aw
141
-
y
y
/`z unadjusted adjusted R
Father's exposure
1 2.413 7.942 26.991 - .138 - 1.023.397 303.374 303.769
2 3.157 13.548 28.979 +.606 +4.583+1.591 304.619 302.899
3 3.068 12.710 29.124 +.517 +3.745+1.736 303.424 301.959
4 + 5 2.852 11.138 28.573 +.301 +2.173+1.185 306.350 305.543
Mean 2.551 8.965 27.388 303.615 303.615
Mother's exposure
1 2.414 7.910 27.074 - .137 - 1.055 - .314 303.539 303.929
2 2.771 10.694 27.913 +.220 +1.729 +.525 304.324 303.727
3 2.779 10.623 27.870 +.228 +1.658 --.482 303.088 302.362
4-t 5 2.694 10.117 27.724 +.143 +1.152 +.336 302.176 301.805
Mean 2.551 8.965 27.388 303.615
ay adjusted _y unadjusted-box-b2/`w-buzz.
b1 _ 8.620 Ax = (xt - x)
b2 - 0.662 low two - w
be - 0.295 ^2 = (~ z)
TABLE 10.13 THE RESIDUAL MEAN SQUARES FROM
THE INDIVIDUAL CELL REGRESSIONS:
FEMALES, HIROSHIMA
(The degrees of freedom are given in parentheses.)
Mothers
1 2 3
cat
cot
Let
1;l,617.30
l(7~995)
2 J1,645.67
~ (696)
3 t1,769.35
l (262)
4 5il,s60.2s
~ (171)
1,566.69
(2,424)
1,782.13
(870)
1,300.74
(177)
1,277.68
(114)
Bartlett's test for between-cell heterogeneity of
mean squares:
4-5
1,621.86
(522)
1,733.04
(85)
1,569.98
(51)
1,417.02
(54)
1,678.38
(1,028)
2,210.23
(194)
2,155.90
(242)
2,151.95
(71)
%a=51.216** DF=15
Bartlett's test for between-cell heterogeneity of mean
squares when category 1 parents are excluded:
%2=26.156** DF 8
x = parity
w_ parity squared
z = maternal age
142
_ ~
tic
rut O x
0 0 c
_ _
~ _ ~ us vat ~ ~ Gs ~ X ~ l_ vat O ~ ~
ox x _ coo ml~= or mo us_ five
Gs O ~ ~ ~ ~ V~ CN ~ ~- 00 ~ V
_ m~ ~ ~ ~ O
. . . . . . . . . . . . . . . .
1 1-~ 1 ~ 1 ~ 1 ~-
~ ~ oo x ~ ~ oo c~ ~ ~ ~ ~r oo v~
CO ¢~\ ~ -~ ~ ~ ~ X 1-~ ~r -
^ _ ~ O x O ~ _ -= ~ ~ ~ ~ ~ O
- 00 ~ mx ^~ - ~ 00 0 - ~_=
. . . . . · . . . . . . . . . .
1 1 - 1 1 1 1 - 1 -~ 1 - 1
x ~ 00
u~ 0 0 r~ ~ ~ °
v~ ~ ~ ~ ~ ~ ~ ~ l_ ax
v~ _ ~ O ~ O O O ~ ~ ~ c
m ~ ~ ~ O
~ ~1 --
1 - 1
ON
v~
-
x
Genetic Effects of Atomic Bombs Chapter X
r~
1
c~
x
1
u~
_~ - l_ _ - - x ~ 0 +~r ~
^w ~ ~ mmo ox'-0 - ~r~ ~ ~0 0
. . . . . . . . . . . . . . . ..
m x V~ = oo r~ ^ \0 ~ X t-~ ~ = 1- ~cO
~ _ 0 r~ ~ ~ r~ oo ~ ~r x c~ ~ ~ ~ ~F4 1
e ~ ~r ~ x ~ ~r ~ x-x r~ ¢\ ~ ~ o v ~c:
W m\° x ~V~o ~xo-~-o~o ~eq ~a'
v~ 1` _ 1-r~ ~ oo ~ x 0 _ ~ 0- -
1-~ r~ r~
~X _ r~O ~
_4 ~O
~ _ ~ X ~ X ~ ~ -- ^= ~ ~ ~ ~ O
- ~ - ~ 0 ~ m~ ~ X" ~ ~ ~ XO ~
cr~-- ~r 0 0 _ oo O - = ^xo~ ~ ~O
c ~X O ~ G~ O ~ ~r ~D ~ O ~ ~ ~ ~ ~r
~t r ~0 o~ 0 r~ m~ ^--~r _= r ~_ c~
, ^ , ~a~
v ~4 - N ~1 00 0 - - - ~O s~
~r rn ~e~
0~ 0 ~-~-0m 0 v--_ ~ 0 Z
o ~ ~ ~ _ ~ x cs ~ ~ ~ ~ ~ 0\ ~ O v ~O _
X ~ ~ O X ~ ~ ~ _ O l_ _ _ CJ cn ~
:^ a~0xo ~ ~-+ r~ V~ X a~ ~ c~- ~r ~ t4 c ~
W ~ ~ ~ ~-X- 1 ~ ~ ~ ~ ~ ~o
mm.~^ m~ 1 ~ 1 ~ ~ v ~o
~C ~ ~
c ~ ~p: ~_
X r~ C~ ~ ~° X ~ ~ O CS ON X° ~ V°~ X O ~·- C. ~V
V > ~- - a) x ~ ~ - ~ m_m ~r~ ^~r 0 ~ ~ Z
x ~x_r`xo~~`o~rx - - ~11 I' E ~u
W oo c\! ~ ~ o ~ v~ ~-° 1 ~ ~ ~- 1 v ~ ~ ~ CO
p v~ _ ', ~ ~ ~ _ _ ~ I t~, N [.14 ~C
_ ~O
a' V~ ~ r~ V~ _ CN ~ ~ r~ ~ ~ ~ ~ X O
m _ ~ ~ ~ +- ~ ~ ~ ~ ~ ~ -= O ~
- = m ~ c~ x x _ m ~ x 0 - ~ _ ~c
~N C~ ~ ~ ~- ~ _ ~ \~ ON ~ ~ O ~ O Z O
° W X r~ ~ ^~0 ~ r^ - X X 0~^ ~ ~ ~ ~r ~`~;
_ o r~ x
~x ~ _ c~ r~
v ~ ~ ~~ ~v,
7 S! c~d
~=~ - oo~ooox~a)cx= - <~ O a ~
_ ~ ~x =-0 ^00 +~=x += ~ ~ ~
~== - ~ 0 ^~= mo o ~ +0 ~ ~c
<: x x v~ ~ x x 00 ~ ~ ~o ~-~ ~ 0 ~ ~v ~ ~0
O W x 0 0 x ~ ~ ~o-~ ~ ~ ~ ~r ~Z V mO
_ v ~¢ -t
0 ~ ,~
~ 0 r~= ~ ~ ~ ~= ~ 0 mx-- ~ Z
c ~ x ~ _ ~ ~ v~ O ~ ~ ~ ~ ~ \0 v~ ~,
_ ................ . .
c ~x ~ ~ ~ ~ ~ ~ ~ 0 0 c~ ~ ~ ~ _ x `^ . v p:
~, ~--~OO-=~mmmm ~_
- - = ~-x ~ 1 r`~ - ~ ~=, ~
o~~0~m ~ - m 1 _ ~, Z ~o
O ~ ~ ~4 ~D C ~ ~
1` ~-X X ~ ~ 0 ~14 ~ ~ v~ ~ ~1 0 ~Ct
~ r~ 0 0N X ~ ~ 0 \0 ~ ~ ~ oO ~ ~ \0 ~ X ~uc
- 1 ~v-~ 1~ l_ ~ V~ 0 C~ ~ m ~ ~ O ~
O ~ ~ ~ O ~ = - ~ ~ ~ ~ ~ ~ m" ~p ·_
- W ~~~ V~ o^-I_ V~ X ~ ~ ~ ~ ~o-~ V ~u4 C~
X ~ ~ O ~ ~ ~ - - _ r^~ ~ ~._
_. ~ _ _ r~ cs ~ ~ ~4 O ° c.
_ ~cn
~:
x a' ~ ~ ~ _ ~ ~ x ~ ~ ~ X v~ ~ ~v,
,,^~= ~ cr`~r ~ ao 0 ~ - = 1-r^= ~ rx O t.Z.]
r ~. . . . . . . . . . . . ~ . . . ~r . ~
X ~ ~ =4 Q ~ O ~ ~r ~ X X 0: ~ _ 1- ~CN ~O
~ - 1- = - O ~ O ~ ~ O ~- ~ ~ -
W ~ ~-~ ~ ~ I~ O-V~ _ l- ~ O" ~
_ ~ ~ ~ r_ V~ ~ _ v~ v~ ~ ~ r~ _ ~_. v,
~o O ~ Cx r ~O
_. ~ ~_ ~
~ ~ ~ ¢\ r~ r~ X r~ ~ X X ~ ¢N ~ ~ eO ~.:.l _
=~ xo=~-or~o~v~mr ~cd
. . . . . . . . . . . . . . . _
C~` ~ 0 ~ ~ ~ r~ ~ X ~ ~ I_ ~ c~ ~ _ .
_ ~ ~ O ~ ~ X v~ X 00 ~ u~ oo v~ ~ rrY
1 ~ v~ O ~ ~ ~ ~ _ ax _ ~ e~ 1-Gs ~
G~V~-0= mo~r x o~ _m t_ _ ~.
00 ~ x0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ _ 00
~ c~ ~ ax o"
_
~ ~ oO~ O ~ ~O t~v-`
co ·^ c~ I~ ~,~ (~ c
The Analysis of the Bintweight Dam 143
Vet Vat
,, _ m
~ o Cal
. . .
~ ~ _4
or ~ vet
'I ~ X
CZ,, ~ ~ Cx
en.
Cat
L Cal o of
o - ~
_
~
C`3
~ ~ 1 1 1
. .
~ 1 1 1 1-
x
. .
CO
C~=
C] ~ V~
~ W ~ ~ ~
~
~ W
P ~
~ W
¢
~
F
o
~:
X ~ V~ X
''- W -mm
o
~:
1 1 1 1
1 1 1 1
o
~ 1 1 1 1 1 C
C)
oo
C~ _' _ ~
mm :^
. .. . .
~ ~ X
1
V~ _' ~:- ~
00 ~ =~= 0 3
cx c~ OX c~ c~ c~ v)
~ O
V~ Gs
.
° 00 cN v4 v
O ~ r~ oo _
~ ~ ~ ^ ~ c~
r~ ~ 0N- ° :'
0O 00 x x ~.
0- ~ x-
l_ ~ r~ ~ r~ 11 11
cr, v ~I
~r 0
o
0 X ~ ~ X 0 0 ) ~o ~
C~ ~ ~ _ ~ Cx
0 ~4 ~ C~ ~ O X ~
~ ~^ ~ ~ ~
_ ~ ~ 0 ~ oo
_ _d ~
~ _ _ _
_=
r~
_ 0 ~ `=
r~
~ 0 ~
>- ~ ~ ~4
X -0+
W ~ ~
_ ~
o
-
m
¢
_ O
>q c~ ~ O
\0
^
w I ~ ~
r~ ~ O
O
N
W ~
-~ X
!
W - .
~ G~ ~
o om
~O ~ ~
W _ ~ ~
. . . .
· · C ·
· o
o ~ ~ ~ .~
~m C m~
1
_4
C~
~:
V
~:
-
C~
~ ~ t_
_ C;N
r~ c4
o-
~o
~ cO tC
mo ~ ~ o
x ~ ~~ a~r _
V~ V~ ~ ~ ~ CJ
V~ ~ Ct~ c~, X ~ (~ °~
oo ~ oo X
_ _. _ _ ~
V) -
~C
C~ ~ ~ o~ ~ ~ ~
(~, ax \C, ~_ ~ ~., 4)
td Ct
r. ~ t_ c~
- l- ax l_ oo oo
~ - ~= 11 11
oo ~ ~ '. ''
r~4 r-~ N \0
V~ ~ ~ V~ V~
r~ ~ ~ ~ V~ ~r
~r x ~r
1~
X ~ C;~ X ~ O
~r~ ~ mx
r~ r~ ~ ~
_ _4 _ _ _
X ~ 0 -
- ~r o== r~
c~x~r 0
-~ X 1 - 0\
V~ O ~ O
~ G~
00 ~ ~ ~ ~ l_
cc ax ~ ~ ~ r~ _
~ ~ ~ ~ ~ ¢S C
~ ~ ^ ^ ^ ^ ^^
- 1- a~ cx ~ G~ _U
~r - ~=
~C
O X ~ O
C ~4 ~ O D C~
~ ~ ~ ~ ~ ~ 1 ~ 1
_ x CN~ ~ ~ 11 11
oo ~ ~-~ ~
-O ~-~- ;^ X
~r
0 x a> -
v~ ~ r~
\0
_ ~ _4 _
. . . .
. . . .
. .
· · ·:
++++
I G~ ~ ~ C ~¢N ~ ~ ¢N
o ~ ~ ^
0 v ~ ~ oo ~r
. . . · . . · ·
~, ~ U~
C~
oo ¢\ o V~
N~ ~ _~ 00
V~
. . · .
1 ~ ~ ~
. .
Z ~
¢ a
E~
~
~
c~
¢
x
E~
Io U~ o
x ~ ~ r~
1
G~
V~ oo
oo o o o oo
C~ ~ C~ ~
a~ ~ oc
~o ¢~ ~
00 ~ U~ ~r
X ....
~. . .
~ . .
o
X
.
V) . .
~. .
·
.
:+ ~
, - =
11
1
1 1
1 1
~ o ~ o
1 o. ~ ~ o. 1
-
I x 13 IN
1 1 1
1 1
X ~ ~
1 ___
-~ ~o~ ~ 11 11 11
~ oO GN 0Or~ _ ~ ~ N
~ ~ ~ 00~ `: a a a
- ~m ~ 1
x
v~ ~00
oo v~
. . . ..
~ ~ ~ _,~
I ~ ~ r~
o C~
. . . . .
=::
V, . .
o
~:
C) .
U~
,. . . .
· · · +
o ~ ~ ~ ~
I ~r
o
.
4 -
.
cd
c
V~
Il a~ ~c~ ~
· 1' ~ 0 0
.
G~
: ~ 11 11 11
C ~ ~ ~=
`
144 Genetic Effects of Atomic Bombs Chapter X
cut
v,
a:
._
~ ~ 1
>
em
a) ~
o
a::
-
0,0 0 ^ ~ _
Go
~ 0 ~ O
_
up
of ~ 00
O
_ ^ _
00 ~ ~
cut ~ ~ 0
- idle DO ~
~ _ ~ _
o
.
0
~ ~ ~0 -
aN ~ ~ _
0
_ vet _
. ~
a_
cut
^ ~ =4 0 ^ ~ _
Go ~ ~ ~ O ~ O
0 ~0 0 0 or ~
00 ,_ ~ _,^ ~ ~ ~ _
_ HI _ ~_4
e<,
Or
, ~
so
-
C~
The Analysis of the 13irthweight Data 145
~ ~ fir
00 0 0
=0~
. . .
~ ~4 ~
0 r`=
~ · vet
cot . .
~0
O
of
on
-
E~
~cat
v ~
a: 0
m
~0
0
cat
Z e,.o
cot
v ~
=4
146 Genetic Effects of Atomic Bombs Chapter X
TABLE 10.22 THE ADJUSTED BIRTHWEIGHT MEANS: FEMALES, NAGASAKI
Y Y
x w z Ax low Liz unadjusted adjusted a
Father's exposure
1 2.820 10.848 28.093 -.191 -1.689 -.480 303.391 303.858
2 3.664 18.379 30.200 +.653 +5.842 +1.627 304.339 302.774
3 3.475 15.960 29.842 +.464 +3.423 +1.269 307.781 306.317
4 + 5 3.305 14.790 29.311 +.294 +2.253 +.738 305.168 304.266
Mean 3.011 12.537 28.573 - 303.690 303.690
Mother's exposure
1 2.916 11.547 28.579 -.095 - .990 +.006 303.384 303.608
2 3.110 13.574 28.606 +.099 +1.037 +.033 303.677 303.457
3 3.229 14.472 28.542 +.218 +1.935 -.031 307.910 307.212
4 + 5 3.011 12.756 27.875 0 +.219 -.698 304.023 303.936
Mean 3.011 12.537 28.573 - - 303.690 303.690
a y adjusted = y unadjusted-box-blow-buzz.
b1 = 7.846
b2 =-0.528
be =-0.291
Ax- (I-x )
Aw _ (w,-w)
Liz = (zig-z3
TABLE 10.23 THE RESIDUAL MEAN SQUARES FROM
THE INDIVIDUAL CELL REGRESSIONS:
FEMALES, NAGASAKI
(The degrees of freedom are given in parentheses.)
Mothers
c~
~. . -
1 2 3 4-5
r1,685.03 1,688.20 1,364.31 1,246.83
11 (6,757) (4,309) (363) (263)
2 r1,675.37 1,7S7.11 1,639.73 1,974.58
~ (1,007) (1,937) (134) (53)
l r1,878.25 1,303.64 2,294.75 2,872.48
31 (106) (125) (38) (14)
4_5 il,691.59 1,821.47 1,506.31 1,867.23
~ (59) (66) (17) (9)
Bartlett's test for between-cell heterogeneity of
mean squares:
x2 = 29.99*
DF= 15
Bartlett's test for between-cell heterogeneity of mean
squares when category 1 parents are excluded:
%2=9-40
DF = 8
x = parity
w = parity squared
z = maternal age
The Analysis of the Birthweight Data
~ ~ c ~ ~ ~
I_ ~ t=~
a ~ ° cd ·- ~ up vet
~ c.`, ~ .~= ~ ~
~ 3 ~0 x x x
~ ~ o z~ ~ ~
cat
3
z
z
o
o
-
a At,,
X'
~-
<: <<
-
cd
o
V)
¢
of
-
L~
m
¢
0 {~s (,, ~ 0
ED C C
o C~ 4
o ~ ~ ~ _
C l C ~
~ C ~ ~ ~ ~ ~ ~ ~
Cat
~ E ° E o
°~ ° ~ c~c ° ° ° ° 3
>.o c, 3 ~
a~
c~
~s°
c
_ _ O
4) ~
:^ ; ~_
,~ ·v, ~ c c
0 0 ~c
~ 04 ~o
. . . .
· {~:
c~ ~
._ v~
~o
0 -
_ .-
~ I ~
- 5=
c~ '
~ ~ .
s~
~o ~ e~
O
u u 0 ~ e _
c ~
~:
._ ._
c
oc
._ ._
v~ v
4 -
0 0
=~=
~d C
c -
0 4-
·° e,.~> ~ V)_
P: ~ =~=
c~ . ~
u' c c
~E = 5 8 * ~ ~ ~ O
, £- <~ Q
-
| ~ ~ ~ ,,,~ O ~2
~Q
_ +
'0) V) C C C -
O O ~C C C
.c~o.oc.e~= X
O O O X +
zzz~' ~
· . . .
· · ·: 11
: :^
. . . ~
o
147
~.4
.: °
. .^
148
city cell for three of the four sex-city cells. But,
from this same table (10.24b), we note that
when exposure category 1 parents are eliminated
both the heterogeneity in regressions and in
residual mean squares largely disappears. Before
we consider the implications of this, let us first
consider what might account for the differences
observed when all exposure cells are utilized.
Table 10.24a, then, provides evidence, albeit
inconclusive at this stage, that birthweight may
be associated with parental exposure. Two
points are involved, namely:
1. In two of the four sex-city cells, the relation
of birthweight to parity and maternal age varies
in a minor but significant fashion among father-
mother cells.
2. In three of the four sex-city cells, the residual
mean squares vary substantially (and signih-
cantly) among the father-mother cells.
Let us consider these points. In point (2),
under the assumption that within a sex-city cell
the observations within a father-mother cell
have homogeneous variance, common mean, and
normal distributions, we should conclude that
the variance differs between the exposure cells,
and that this obtains for most sex-city cells.
Normality may be safely assumed, but there
exists the possibility that the other assumptions
are invalid here. Accordingly, two alternative
or supplementary explanations of the Endings in
point (2) must be entertained, namely:
(a) The variances are different between ex-
posure cells, and presumably due to irradiation.
(b) The variances are different between ex-
posure cells due to unaccounted-for concomitant
variation. For example, if there were year-of-
birth effects, or a socio-economic status effect,
then differences in the residual mean squares
might reflect unequal representations with re-
spect to year of birth, or social background.
Similarly, for point (1) we must entertain more
than one explanation, namely:
(a) The relation of birthweight to parity and
age of mother is different among exposure cells
and presumably due to irradiation.
(b) Factors partially correlated with age and
parity may differ between exposure cells and
thus give rise to an apparent variation in the
relation of birthweight to parity and mother's
age.
Genetic Effects of Atomic Bombs Chapter X
What evidence is available which might permit
a choice among these alternatives?
In addition to data covering maternal age and
parity, information is available on two other
concomitant variables which are relevant to the
questions raised in the preceding paragraph.
These variables are year of birth (for all in-
fants) and the parental socio-economic status
(for a random 10 per cent of infants). Let us
consider first the effect of year of birth on the
residual mean squares.
Two alternatives which might be entertained
here are the following: Firstly, we could assume
that the relationship of mother's age and parity
to birthweight is constant over the years within
a given exposure cell, but that the intercept
(mean) of the regression may vary from year
to year. This would lead us to fit a model
asserting that
E (`)ijrk`) = miJr + bi (XiJrk-Xtj) +
b2 (`W,~jrk-Wq,j`) + iO3 (`Z',jrk-Z,,j`)
That is to say, the expected value of the kth
observation on birthweight in the rth year of the
ij~h exposure cell (sex and city are fixed) is a
function of the mean of the rt7t year in the ij~h
cell, of parity, of parity-squared, and of ma-
ternal age. Secondly, we might prefer not to
assume that the relationship of mother's age
and parity to birthweight is constant over years
within a given exposure cell, and hence to fit
a model of the form
E (irk) = m,,jr + tar (XiJric-X~jr) +
/°2r (`W1,jrk-Wi~jr`J + bar (~ZzJrk-Z7,jr`)
The latter approach is, of course, equivalent to
fitting a regression in each of the 112 year-
exposure combinations within a given sex-city
cell. It is questionable whether the increase in
precision of the latter approach over the former
is sufficient to justify the not insignificant addi-
tional labor in computing some 448 regressions.
As a first approximation, then, we have elected
to proceed using the simpler (the first) model.
To determine whether year of birth contrib-
utes significantly to the variation in birth-
weights, within exposure cells, following the
removal of maternal age and parity effects, we
may employ the mean square ratio test. The
latter test consists of forming the likelihood
ratio, say L, of the "mean square following re-
moval of age and parity" to the "mean square
following removal of age, parity, and year."
The Analysis of the Bir~hweight Data 149
We assert that year of birth contributes signifi-
cantly if L>Lo where the critical value, Lo' is
given by
L-f+ (J-f)Fo
o- f,
and where f and ft are, respectively, the degrees
of freedom associated with the lesser and the
greater mean square, and To is the critical F
TABLE 10.25 THE DISTRIBUTION BY PARENTAL EX
POSURE OF THE RESIDUAL MEAN SQUARES AFTER
REMOVAL OF VARIATION DUE TO YEAR OF
BIRTH OF THE INFANT: MALES,
HIROSHIMA
(Degrees of freedom are given in parentheses.)
Fathers
v,
at)
~ ,
it.
o
TABLE 10.26 THE DISTRIBUTION BY PARENTAL EX
POSURE OF THE RESIDUAL MEAN SQUARES AFTER
REMOVAT OF VARIATION DUE TO YEAR OF
BIRTH OF THE INFANT: FEMALES,
HIROSHIMA
(Degrees of freedom are given in parentheses.)
Fathers
In Tables 10.25 to 10.28 are given the distri-
butions by parental exposure of the residual
mean squares following removal of the "year-
of-birth effect" for the four sex-city cells. In
three of the four sex-city cells the residual mean
squares do not, now, differ significantly one
from another (two of these three previously
revealed significant heterogeneity among the
mean squares).
TABLE 10.27 THE DISTRIBUTION BY PARENTAL EX
POSURE OF THE RESIDUAL MEAN SQUARES AFTER
REMOVAL OF VARIATION DUE TO YEAR OF
BIRTH OF THE INFANT: MALES,
NAGASAKI
(Degrees of freedom are given in parentheses.)
Fathers
, ~
1 2 3 =5 1 2 3 =5
1 (1,709.60 1,793.66 1,835.06 2,347.31 1 r1,805.73 1,712.89 2,359.97 1,465.77
W(8,662) (735) (286) (190) ~ (7,278) (1,059) (112) (63)
2~1,639.79 1,786.50 1,982.83 1,982.08 2 r1,782-86 1,854.71 2,133.38 2,051.48
W(2,707) (889) (182) (105) ~ (4,644) (2,015) (126) (94)
3 [1,790.77 1,747.22 1,764.08 1,647.70 O r1,771-84 2,166.44 2,544.20 1,542.99
W(1,056) (210) (247) (68) ~31 (330) (121) (41) (5)
4 5r1,597.92 1,914.44 1,811.33 1,745.37 (5 {1,643.25 1,824.87 3,360.16 1,002.24
- ~ (532) (99) (39) (46) ~ (263) (45) (9) (6)
%2 = 21.147 DF = 15 %2 = 20.442 DF 15
TABLE 10.28 THE DISTRIBUTION BY PARENTAL EX
POSURE OF THE RESIDUAL MEAN SQUARES AFTER
REMOVAL OF VARIATION DUE TO YEAR OF
BIRTH OF THE INFANT: FEMALES,
NAGASAKI
(Degrees of freedom are given in parentheses.)
Fathers
_ . ~,
1 2 3 (5 1 2 3 =5
r 1 rl,611.26 1,646.48 1,773.60 1,941.68 rl,680~50 1,753.30 1,892.83 1,591.88
:(7,990) (691) (257) (166) 1) (6,752) (1,003) (101) (54)
2~1,559.88 1,786.51 1,309.50 1,163.41 2 rl,688.58 1,753.37 1,344.54 1,865.09
A ~1(2,419) (865) (172) (109) ~)(4,305) (1,932) (120) (61)
JO 3;l,682.01 2,224~61 2,181.14 2,219.93 0 3 rl,675.05 1,662.10 2,280.34 1,752.83
:(1,023) (189) (237) (66) ~ (358) (129) (33) (13)
=5 il,603 27 1,80~2~62 1,445.23 1,321.28 4 rl,505~33 2,050.00 4,305.18 2,363.29
~ (517) (80) (46) (49) 5l (259) (49) (7) (5)
%2 = 45.110* * DF = 15 %2 _ 22.003 DF = 15
(here Fo5 ) at (f'-f ) and f degrees of freedom.
In all sex-city cells, year of birth can be shown
to exert an effect; this effect is, however, signifi-
cant in only two instances, namely, Hiroshima-
females and Nagasaki-males. Under the circum-
stances, then, to prevent ambiguity it seems
appropriate to remove the year-of-birth effects in
all cells.
view of the fact that the variances were
heterogeneous in only one sex-city cell (Hiro-
shima-females) when year of birth was taken
into account, no attempt was made to exploit
the data with regard to socio-economic status.
The latter decision stemmed primarily from the
fact that analysis of the socio-economic data
would, since such data are available on only 10
150 Genetic Ejects of Atomic Bombs Chapter X
per cent of the observations, be applicable only heterogeneous among exposure cells (all ex-
inferentially to the problem of whether residual posure cells considered) in three of the four
concomitant variation could account for the
heterogeneity of the variance estimates within
the Hiroshima-females cell.
What, now, may we conclude with regard to
the effect of parental exposure on birthweights ?
Three points are involved, namely,
1. Does parental exposure affect birthweight
means ?
2. Does parental exposure affect the relation-
ship between birthweight and concomitant vari-
ables, notably maternal age and parity?
3. Does parental exposure affect birthweight
variances ?
With regard to birthweight means, we cannot
demonstrate a significant effect of parental ex-
posure in any one of the four sex-city cells.
With regard to the regressions of birthweight
on parity and maternal age, significant differ-
ences obtain among exposure cells in two sex-
city cells. In one of these instances, significance
does not obtain if attention is limited to only
those infants born to parents both of whom
were exposed. In view of the known somatic
effects of irradiation, it would seem most likely
that the regression differences, if real, reflect
either a "disaster" effect or a direct (non-
genetic) effect of irradiation. Lastly, with regard
to the effect of parental exposure on birthweight
variances, we note that, when maternal age and
parity are removed, the variance estimates are
sex-city cells. If, however, year of birth is also
removed, only one sex-city cell continues to
exhibit significant heterogeneity in the variance
estimates among exposure cells. Moreover, we
note that if attention is limited to those termina-
tions to parents both of whom were exposed,
the variance estimates among the exposure cells
are significantly heterogeneous in only one sex-
city cell even if year of birth is not removed.
These facts raise some doubt as to the reality of
the differences in mean squares as an irradiation
effect, especially if one assumes that a consistent
pattern is the sine qua rzon of a radiation-
induced change. Whether consistency is a valid
assumption is difficult to appraise. One can
postulate certain parental interactions or rela-
tionships between fetal resorption and degree
of radiation damage, both admissible hypotheses,
from which it would not necessarily follow that
the variance would be similarly affected in all
sex-city cells. The conservative interpretation
of the data with regard to the birthweight vari-
ances would be one which asserts no clearly
demonstrable effect of parental irradiation on
the spread of birthweights.
10.5 Summary. There exist no consistent
findings suggestive of an effect of parental ex-
posure on (a) birthweight means, (b) the rela-
tionship of maternal age and parity to birth-
weight, or (c) birthweight variances.
