METABOLIC
REFERENCE
STANDARDS
FOR
THE
NEONATE
John C. Sinclair, M.D., Jon W. Scopes, M.B., and William A. Silverman, M.D.
Department of Pediatrics, College of Phyricians and Surgeons, Columbia University; Babies Hospital,
Columbia-Presbyterian Medical Center, New York; and Hammersmith Hospital, London, England
(Received July 14; revision accepted for publication November 22, 1966.)
J.C.S. is supported by Research Career Development Award of Public Health Service (No. 1K3
HD-34,992-01); J.W.S. is supported by NIH grant T1-HD-51; W.A.S. is career investigator of the Health
Research Council of the City of New York (Contract No. 1-181).
Presented in part to the American Pediatric Society, April 27-28, 1966, Atlantic City, an(l to the
Neonatal Society, November 10, 1966, London.
ADDRESS: 630 West 168th Street, New York, New York 10032.
PmIAmzcs, Vol. 39, No. 5, May 1967
724
ESTING METABOLISM RIIlOfl newborn
babies studied under thermoneutral
conditions during the first (lays of life shows
appreciable variability when expressed in
terms of birth weight. In previous reports
we have found that j)art of this variation is
a systematic one associated with gestational
age, rate of intra-uterine growth and
post-natal age.’’3 In this report, we further
exam-inc the variation in resting metabolism
among babies whose
birth-weight-for-gesta-tional-age relationship indicates a usual rate
of intra-utenine growth. lsing the findings of
others who have analyzed the body
corn-position of fetal carcasses, we derive
“cx-pected” compositions of the babies we
stud-ied. Various standards, defined in part from
these considerations of body composition,
will be related to the metabolic data in order
to develop certain concepts of the body
size-metabolism relationship )articu1an1y
pertinent to the newborn infant.
METHOD
The oxygen consumption data on which
the calculations are based have previously
been reported.’’3 Of the 194 babies studied
in these two series, those who fulfilled all of
the following criteria were selected: (1) age,
2-10 days; (2) no evidence of
cardiorespira-tory or other disease;
(3)
rates of oxygenconsumption measured in the resting baby
under thermoneutral conditions, breathing
room air; (4) baby “normally grown” in
utero (i.e., birth weight between 10th and
90th percentile on Colorado intra-uterine
weight curve).4
Forty-nine American and 43 British
babies were found to fulfill these criteria.
The methods used for calculating gestational
age, for achieving a thermoneutral steady
state, and for the measurement of oxygen
consumption have been described in previous
publications.’3 All volumes given are at
standard temperature and pressure, dry
(STPD).
Metabolic reference standards(MRS)
to which the observed oxygen con-sumptions were related included body weight,surface area, body weight fat-free both’
weight,6 body weight minus extracellular
fluid (ECF), and body weight iiiinus ECF
liliflU5 fat.7 In calculating each of these
standards, the birth weight of the baby was
taken as the body weight, regardless of the
actual weight on the day of study.
CALCULATION OF THESE VARIOUS
REFERENCE STANDARDS
An estimate of fat and ECF in our
sub-jects was essential. Data on carcass analyses
of fetuses and newborn infants weighing
570 to 3,570 gin reported by Canierer,8” lob
and Swanson,’#{176} Dju, et a!.,” and Fee and
Weil’2 were consulted. The data generally
indicated the body weight but not the
gestational age of the subjects. In the
ab-sence of information on gestational age, we
have based our calculations on body weight
and made the assumption that the majority
of the subjects whose body composition was
determined by analysis bore a similar
weight-for-dates relationship to those whose oxygen
consumption we measured and who were
within the 10th to 90th percentile on the
Colorado intra-utenine weight curve. We
sub-TABLE I
BODY Con’osITIoN OF TIlE FETUS
TABLE II
2O
Correlation Regre8:ion
n 2: y f S.E.r Equation S.E. line
log fat (gm)
log ECF (ml)
.97
.992 .36
log y=.l8O log x-5.0570
log y=O.8O5 log z+O.3415
0. 1380
0.0.51
jects on the basis that they were stated to
be abnormal (Fee and \Veil’s infants of
non-(liabetic mothers No. 18 and No. 23).
Body weight, chemically extractable fat,
total chloride and calculated ECF volume
of these carcasses are listed in Table I. ECF
volume was calculated from total chloride
content by assuming a volume of
distribu-tion of chloride equal to the extracellular
fluid, a plasma chloride concentration of
105
mEq/l, a Donnan factor of 1.04 foruni-valent anions, and a plasma water fraction
of 93% of plasma. Thus,
ECF volume (ml) =
total chloride content (mEq) X 1000.
105 X 1.04
.93
A straight line relationship was observed for
log fat vs log body weight, and for log ECF
vs log body weight. Our predictions were
made from the calculated best lines (Table
II).
Surface area was calculated from body
weight alone by means of Meeh’s formula
(A
= k %\‘2/3)13 using Lissauer’s constant(k=
10.3).’
RESULTS
Table III lists the 92 babies we studied,
giving the birth weights and oxygen
con-sumption rates. This group comprises our
joint experience. We have analyzed the
British an(l American series separately and
each shows the same findings with respect
to the relationship between \02/MRS and body
weight. Therefore, in the results that follow,
the two series have been combined.
. source of Data
CamererL’
i1iy
Iiegh.t Fat Chloride
ECF (ral-culaled) (gm) 3,348 3,048 ,755 ,616 ,476 (gn) 378 366 443 358 Q70 (mEq) I7O. 163.6 139.9 13.S 15.7 (ml) 1,450 1,394 1,l9 1,19 1,071 IobandSwanon’#{176}
Fee and Wed”
390 .570 1,010 960 1t05 1,555 1,545 1,615 ,915 65.0 999.5 1,478.9 1,866. ,057.4 7.1 41. 7.4 40.9 tZ 6.9 31.1 64.0 4.Q 81.3 74.6 99.7 5.5 99.3 63.0 lOLl 195.3 1491 1.0 44.9
49.3 : 64.5
88.9 100.6 17.1 111.3 173.8 15.9 350.9 348.4 535.8 545.1 693 849 8*6 870 l7l 38.3 549.0 8.57 948 1,073
Dju ci al.” 3,570 40
Figures 1 through 6 illustrate the
asso-ciations we observed between
‘7o2/MRS
(or-dinate), and body weight (abscissa), among
these 92 babies. The values for VO,IMRS are
highly dependent on body weight in every
case except one-where the MRS is body
weight minus ECF. Thus (Table IV), the
correlation coefficient expressing this latter
relationship is nearly zero, and when related
to its standard error it is not significantly
different from zero. It is therefore concluded
that, within the range of body weights
in-eluded in this sample, there exists a Vo,/body
weight minus ECF relationship that is not
significantly correlated with body weight.
If any of the other tested reference standards
log body weight (gm)
19 log body weight
(gm)
110-__ 00
0
0
a
a
a 0000
a0
a 0 0
12”
I0’
6”
I0
.4-.c9
0’
. I
4. a 0. C.
0 .>
.5 I 1.5 Z 2.5 3 BODY W1G14T (Kg)
Fia. . See Figure 1 legend.
a 0
0 a
‘I
O 0
x:.o0%0
a a0
:
000a a
ox a
9
4.
., SI
>
0 A6
.5
0 0
x a
a a
3
BODY WEIGWT (kg)
35 4 ‘.5 I 1.5 a 2.5
BODY WEIGI4T (kg)
3 iS 4
FIG. 3. See Figure 1 legend. FIG. 4. See Figure 1legend.
x
100+ 0 0
0
BODY WEIGHT (kg)
Fio. 1. Oxygen (‘o11SU1111)tioll of American (x) and
British (o) newborn babies related to various metabolic
standards as a function of body weight. The Inetabolic standards, derived as described in the text, include (Fig. 1) calculated surface area, (Fig. ) body weight73, (Fig. 3) fat-free body weight, (Fig. 4) body weight,
(Fig. 5) body weight minus ECF minus fat, aIl(l (Fig. 6) body weight minus ECF. Values for correlation 811(1 regression are given in Table IV. The random
variation around each of the regression lines is similar; however, the removal of the systematic variation
(Fig. 6) greatly improves the prediction from a mean
value.
0 are substituted, this in(lependence of body
weight is lost, and a highly significant
cor-relation is introduced. The use of these latter
metabolic reference standar(ls therefore
con-tributes to a systematic variation in the
ex-pression of metabolic rates among neonates.
Over the weight range studied, there is
greater relative variability (expressed by the
coefficient of variation) when metabolism is
referre(l to these standar(ls (Table V). The
magnitude of the systematic variation
in-troduced by the choice of metabolic
ref-erence standard is indicate(l in Figure 7.
COM MENT
Statistical Considerations
Tanner’5 has summarized some statistical
problems involved in the expression of
physiologic measurements. If a proportional
relationship should exist between a
inca-surement (e.g., ‘Vo2) and a metabolic
ref-erence standard (e.g., body weight-ECF)
over a wide range of weight values, the
stan-(lard can be used as a “ratio standard over
that weight range; that is, the expression
y = kx
holds good over the range of weight values
studied. The constant k represents the mean
value for the data on which the standard is
founded.
More commonly, however, such a
pro-portional relationship (loes not exist, but
rather a relationship given by the regression
equation
y=a+bx.
a 0
so 0
%ox00o0
a0O 0% 00
a 0 0 0
0% 0 0
0a 0 0
a
3.5 TABLE III
Bony \VEIGIIT AND OXYGEN CoNsuIvrIoN
a
OFNEWBORNINFANTS a 0
a
---
---.-
---
---
aAmerican Series British Series
Body J1’eight b, Body JVeight 1’02
(gat) (ml) (gui) (ml)
750 3.89 980 5.07
900 4.62 1,080 4.90
950 4.72 1,150 6.60 I .5 2 2.5 3
BODY W(IGHI’ (Kg)
950 5.31 1,280 5.63
990 5.63 1 ,330 7.31 FIG. 5. See Figure 1 legend.
1,02(1 5.46 1,380 7.08
1 ,030 4.85 1 ,430 6.43
I,100 5 .70 1 ,460 7 .55 throughout the present study in relating
1,130 5.90 1 ,500 7.04 0/RS to
body
weight
(Table IV).1,140 6.03 1,520 9.51 As Figure 7 shows, serious error might
re-1,180 5.52 1,660 8.18
suit in predicting metabolism from an
as-1,190 5.90 1,840 9.86
1,240 7.71 1,870 8.74 5uITle(l mean value (e.g., for
Vo2
per unit1,270 6.97 1,870 14.30 surface area). That is, a small baby would
1,280 7.15 1,930 9.92 have too high a predicted value, or his
inca-1 ,330 7.09 1 ,960 1 l.10 sured oxygen consumption would be
re-1,400 8.24 2,005 9.57
1,400 8.15 2,080 11.76
garde(1
as too
low; likewise, a large babyI ,4’20 7 .39 2,180 16.46 would have too low a predicted rate, or his
1 ,430 6 .48 2 ,300 13 .54 measured consumption would be regarded
1,430 6.95 2,340 15.28 as too
high.
I ,450 7 .71 2,360 12 .63 Such systematic errors can be avoided by
1,470 6.40 2,380 14.35
I ,500 9.98 2,430 11 .48 predicting metabolism not from a mean
1,530 8.53 2,460 15.01 value (e.g., for Vo2/kg) but from a regression
1,560 7.12 2,500 12.60 (e.g., of Vo9/kg on body weight).
Alterna-I,580 9 .31 2 ,520 13.68 tively, the reference standard
body
weight-I,600 9.95 2,640 15.81 ECF, which approaches the special case
1,760 10.38 2,750 15.12
where the ratio and regression standards
1,800 10.88 2,860 17.14
I,850 10.65 2,950 17 .54 coincide, permits oxygen consumption to be
I ,850 12 .30 2 ,980 21 .56 predicted from body weight-ECF using a
1 ,960 12.23 3,000 20.99 mean value for
k. Thus,
although
we should
1 ,980 10 .43 3 ,000 17 .47 speak only of Vo2/unit surface area or V02/
1,990 16.79 3,020 23.68
unit body weight in relation to the mean
cx-‘2,015 15.39 3,160 17.98
‘2,070 16.53 3,250 19.83
‘2,130 14.04 3,260 18.56 .
L)T
‘2,255 12.78 3,550 22.93 w
I a
‘2,320 12.88 3,650 ‘23.80 lb ,
‘2,380 19.74 3,720 ‘23.63 ‘ 0
l4 a
‘2,750 16.75 3,800 ‘24.17 x a ox
>. a ,5 o a I
‘2,995 20.34 3,840 29.89 0, ‘ 0 X..
3,040 20.43 .‘ I “o o soW 000
ox a 00
3,110 20.12 “‘-I0 0% 0 0 0 0 0 0
3,250 ‘22.88 ‘:/ #{176}
*
#{176}#{176} #{176}0
s#.-.-.-..-- I I I I I I I
3,450 ‘26.29 . I IS 2. 2.5 3 3.6 4
3,540 ‘24.18 BODY WEIGHT (Kg)
3,940 30.02
S
Cerrelalion
y r S.E.r
I
Regression Equation S.E.r SE. line n 92 92 92 92 92 92 body weight (kg) body weight (kg) body weight (kg) body weight (kg) body weight (kg) body weight (kg)surface area (1132)
If).,
l)Od’ weight (kg73)
fat-free weight (kg)
102
I)O(l\’weight (kg)
l)O(IV veighIt IIIIIIUS
ECF IIIIIIUS fat (kg)
JO..
h)o(1’ Iveigilt IflillilS
ECF (kg) .857 .828 .695 .559 .511 .084 .105 .105 .105 .105 .105 .105 8.18 7.90 6.63 5.33 4.88 0.80
y= 19.65x+31 .81
y=l.71x+3.58 y=O.98x+4.34 y=0.64x+4.58 y=l.29x+l0.95 y=0.16x+11 .35 9.91 0.97 0.85 0.79 I .82 I .55 728 TABLE IV
RELATION BETWEEN BoDY VIEIGIIT AND OXYGEN CONSUMPTION/VARIOUS METABOLIC STANDARDS
pecte(i for a baby of a specific size, we may
speak of Vo2 per unit body weight-ECF
with respect to babies drawn from the same
population as tile sample studied, regardless of size.
Physiologic Considerations
Changes in body composition during fetal
life are profound as compared to those
oh-serve(I during postnatal life. The two most
striking changes are a
decrease
in proportionof body water and an increase in proportion
of body fat.’6 The
decrease
in proportion
of
body
water
is predominantly
due
to a
de-crease in proportion of extracellular fluid.
These
changes
have obvious
relevance
to the
problem of
expressing
the
“metabolic
rate”of babies born after (lifferent periods of
gestation.
Benedict and Taibot’7 carefully examined
the relationship of metabolism of infants to
body weight. Although, in general, larger in-fants showed the larger heat production, the
data
were widely dispersed around a line ofgeneral
trend,
and
it
was not possiblecon-fidently to
predict
metabolism
from bodyTABLE V
RELATIVE VARIABILITY OF NEWBORN
BABIas’ METABOLISM REFERRED TO
VARIOUS STANDARDS
Metabolic Reference Standard
Vn,JReferewe Standard , Mean Standard (mi/mill) Deviation Coefficient ‘‘ Jaroation % Surface area Body weight 73 Fat-free body weight Bodyweight
Body weight minus ECF minus (at
Body weight minus ECF
7.2/m’ 7.10/kg73
6. 36/kg
.5.88/kg 18.60/kg
11.67/kg
19. 1
I.7
I.iS 0.95 2. 10
I .55
6.5
I.S 18.6 16.1 15.5
+4C
#30
+25
2
LI
410
L
z
0 -10
>-20
LaI
-30
weight. Subsequent investigators5 ‘18.1 9 have
related mean metabolism of many species,
not simply to body weight but to a
frac-tional power of body weight, the relationship
being expressed
by
an equation of the formy = ax’, in which the value of the exponent b
is between .73 and .75. This relationship was
endowed with an aura of general biologic
validity by the demonstration that it was
fairly consistent over a range of body sizes
from the mouse to the elephant.5 A value for
b of .73 is not very far from 0.67, which
ac-cording to the surface area law is the power
to which weights or volumes of similar
geometric figures must be raised to give
(luantities proportional to their surface
areas. Thus, metabolism can also be related
to surface area, and an inherent physiologic
validity for this latter relationship has been
claimed by assuming that the magnitude of
the basal energy production in homeotherms
is dependent on the rate of cooling of the
body, which in turn is related to the size of
the body surface. However, Helnmingsen2#{176}
2 S
BODY WEIGHT
()
FIG. 7. Systematic variation in expression of metabolic rates of newborn babies. The regression line for each reference standard is drawn so as to show the percent
underestimate or overestimate in the prediction of metabolism of babies of various sizes when that
prediction is based on a mean value for To/reference
standard.
employed an extensio ad absurduin
argu-ment to attack the notion that surface area
has a physiologic role in determining the
magnitude of the basal metabolism in
homeotherms. He showed that metabolism
is linearly related to a fractional power of
total mass of poikilothermic animals and of
plants, just as it is for homeotherms, and
that the exponent of weight expressing this
relationship
is
near that for surface area.Since, in poikilothermic subjects, it is
dif-ficult to imagine that the observed
propor-tional relationship between resting energy
expenditure and surface area is determined
by physiologic regulation of heat production
to keep these organisms warm or cool, it has
been suspected that the proportionality in
both homeotherms and poikilotherms is, in
a physiologic sense, an accidental one.
Another approach assumes that resting
metabolism is related in a simple
propor-tional
way to some fraction of the bodyweight, which we might call the active tissue
mass. This concept implies a division of the
body into two main compartments-one
metabolically active and one relatively
in-active.
The magnitude of the basalmetabo-lism will be related to the size of this active
compartment. The concept of an active
tissue mass that was responsible for energy
exchange
was invokedby
Benedict andTalbot’7 as early as 1914. When they
corn-pared the heat production of infants of like
body weight and height, but of different
ages, they found that in each case the older
infant had the greater heat production.
Since the older infants were distinctly
under-weight,
they
suspected
that
a larger
pro-portion of their bodies was composed of
active protoplasmic tissue. In concluding
that “the active mass of protoplasmic tissue
determines the fundamental metabolism,”
they noted the lack of a direct mathematical
measure of the proportion of this tissue.
Since that time, the active compartment has
been variously estimated as the lean body
mass2’ (total body weight minus storage fat),
fat-free body weight6 (body weight minus
body fat as determined by petroleum ether
Minne-sota partition system (body weight iiiinus
body fat minus bone mineral minus
extra-cellular fluid), or “body cell mass” as
(Ic-rive(I from total exchangeable potassium.22
It should be remembered, however, that
each of these approxiniations of the “active”
tissue mass is energetically heterogeneous,
and changes in the mean metabolic rate of
tile total cell mass, however defined, can be
easily produced by changes in the
propor-tion of tissues having widely varying levels
of oxygen consumption in the basal state.
The present (lata suggest that, as birth
weight increases, metabolic size increases in
greater proportion . This observation stands
in sharp contrast to the general biologic rule,
derived from inter-specific comparisons of
resting metabolism among adult members of
various species, that the metabolism/body
weight ratio decreases with increasing body
size.
As a result of this “neonatal violation” of
the rule, some interesting corollaries occur.
First, any metabolic reference standard
based on an exponent of body weight of less
than I (e.g., body weight or surface area
however calculated) will tend to magnify
the l)re(licti\e error when used as a ratio
standard and when the pre(Iiction is based
on a mean value. Second, the physiologic
validity of surface area as a MRS would
appear to be further questioned : the beech
tree, which un(loubtedly does not regulate
heat production, has been found to
metab-olize in proportion to its surface area;2#{176}but,
the metabolism of tile newborn infant, who
does regulate heat production, bears less
PrOPOrtionality to surface area than to any
other parameter tested. This observation
ex-tends that of Talbot and co-workers, who, in
a series of early publieations,2325 also noted
a lack of I)roPortionalitT between surface
area an(I heat Production among newborn
babies and doubted any necessary
physio-logic relationship between these two
van-ables.
It is necessary to postulate an exponent
of body weight of greater than I in order to
produce a proportional relationship between
metabolism among babies of various sizes,
and body weight’. We find such a concept a
sterile one and prefer to think in terms of a
component of body weight that (letermines
metabolism which is increasing in greater
proportion than body weight with increasing
body
size. This component, on our empiricalfindings,
is not represented by the fat-freeweight; fat starts to accumulate late in fetal
life an(l forms an increasing percentage of
body weight with increasing gestation.
More-over, it is unlikely that the concept of a
metabolically inactive fat cOllll)oIleflt , wi(lelv
prevalent in adult physiology, can he
extrap-olated to the newborn baby, in view of the
known nlicroscoj)ic, J)hysiologic, and
bio-chemical differences of adipose tissue in the
newborn versus the adult.26’27
The “active cell mass” has been defined
(Minnesota partition system7) as total body
weight minus ECF minus fat minus bone
mineral. (We have not consi(lered bone
mineral in our newborn babies in or(ler to
simplify the calculations. It probably
ac-counts for only 1 to
%
of the body weightof the newborn.) Although the compartment
body weight minus
ECF
minus fat is moreconstantly related to metabolism than is
body weight, the best proportionality was
observed when fat was included as part of
the active cell mass, and the active
com-partment was defined siniply as body weight
minus ECF.
The significance of this relationship is
conjectural. It is possible that this
em-pirical fit is not meaningful in a physiologic
sense. We are aware that an empirical
find-ing cannot necessarily be interpreted as
having a physiologic basis ; however, any
true physiologic law must be found to fit
empirically. It seems to us likely that the
observed variation in resting metabolism
among newborn infants-expressed on a
body
weight
basis-is
partly
determined
by
the striking changes in body composition
during fetal life. It is intriguing to us that
when fat-chemically extractable fat, not
adipose tissue-is included as partof tile
ac-tive tissue mass, the fit with the Vo data is
best. Although 5OlC fat is
contained
ill cellwalls, etc., the majority of chemically
cx-tractable fat is to be found store(l within
baby might therefore serve as a marker for
the mass of his adipose tissue, indicating
in-directly that adipose tissue accumulates in
greater proportion than body weight with
increasing maturity. Other components of
the active tissue mass-brain, liver, heart,
kidney, etc.-also grow at different rates
during gestation. In particular, the brain
forms a greater percentage of body weight
early in gestation, rather than in the later
stages. Thus, the relative contributions of
various organs and tissues to the active tissue
mass varies with the size and maturity of the
infant. Witll increasing birth size, brain is
l)roportionately decreasing and adipose
tis-sue proportionately increasing, but ‘o2/kg
active tissue iiass remains cOllstant. This
has interesting inlplications as to the
meta-bolic rate of adipose tissue, even in the
rest-ing, thermoneutral newborn.
We carefully excluded froni the present
considerations the oxygen consumption data
on the babies whose weight-for-dates
rela-tionship indicates a retarded rate of
intra-uterine growth. No data exist from which
the body composition of such babies can be
confidently predicted ; since they are a
minority, it would be unsafe to extrapolate
to them the data obtained on fetuses and
nesvborn infants in general. We found in
un(lergrown infants a significantly higher
oxygen
-
consumption ler kilogram bodyweight during the first days of life, and a
larger j)ostnatal rise in oxygen consumption,
than ill normally-grown infants of similar
Size.1”3
Jf
our hypothesis of the bodycOrn-position-oxygen consumption relationship
among newborn babies can be extended
to these “undengrown” infants, it would
pre-(lict a slnaller ECF for body weight among
these subjects than in normally grown ones
of similar birth weight.
It
is appropriate to eIllpllasize that thepresent data are derived from measurelnents
of resting metabolism in babies whose body
composition is predicted, not measured. The
predictions have been based on carcass
anal-ysis of subjects of similar size but who were
not necessarily comparable in rate of
intra-uterine growth and postnatal age, and who
were obviously selected in that all were
either stillborn or died soon after birth.
Con-cepts developed herein which relate body
size and body composition to metabolism
in newborn babies need to be supported by
studies in which these parameters are
con-currently measured in the living neonate.
SUMMARY
Oxygen consumption of 92 normally
grown newborn babies of birth weight 750 to
3,940 gin has been expresse(l in terms of
various metabolic reference standards in
order to identify any systematic variation in
expression of metabolic rate that is
intro-duced by these bases of reference in the
newborn population.
It
is postulated that differences in bodycomposition comprise a contributory factor
to tile variation among newborn babies in
rate of oxygen consumption per kilogram
body weight.
The predictive error from a mean value is
increased if surface area, body weight73, or
fat-free body weight is substituted for body
weight as a metabolic reference standard.
By taking into account known changes in
body composition of the fetus with
increas-ing nlatunity, a compartment representing
the active tissue mass is calculated. This
corresponds closely to body weight minus
extracellular fluid and includes fat. Rate of
oxygenconsumptionis
proportional to thesize of this compartment over the range of
body weights studied.
Implications are discussed as to the
meta-bolic rate of adipose tissue in the newborn
and body composition among undergrown
babies.
REFERENCES
1. Scopes, J. \V.: Studies in oxygen consumption of nesvborn babies. Phi). Thesis, University of
London. 1965.
2. Scopes, J. W.. and Ahmed, I.: Minimal rates of oxygen consumption in sick and premature
new-born infants. Arch. Dis. Child., 41 :407, 1966.
3. Sinclair, J. C., and Silverman, W. A. : Intra-uterine growth iii active tissue mass of the
hu-I11I1 fetus, with particular reference to tile under-grown bal)y. PEDIATRICS, 38:48, 1966.
4. Lubchenco, L. 0., Hansman, C., Dressier, M., and
liveborn birth weight data at 24 to 42 weeks gestation. PEDIATRICS, 32: 793, 1963.
5. Brody, S.: Bioenergetics and growth. New York:
Reinhold, 1945.
6. von Dobeln, W.: human standard and maximal
metabolic rate in relation to fat free metabolic
mass. Acta Physiol. Scand. (Suppi. 126), 37:1, 1956.
7. Brozek, J. : Measurement of body compartments in nutritional research : Comment on selected
methods. in Methods for Evaluation of Nutri.
tional Adequacy and Status. Washington, D. C.:
National Academy of Science-National Re-search Council, 1954.
8. Camerer, W., Jr. : Die chemisehe
Zusammenset-zung des Neugeborene. Z. Biol., 39:173, 1900.
9. Camerer, W., Jr. : Die chemisehe Zusammensetzung
des neugeborenen Menschen. Z. Biol., 43:1. 1902.
10. 101), V., and Swanson, W. W.: Mineral growth of
the human fetus. Amer. J. Dis. Child., 47:302,
1934.
11. Dju, M. Y., Mason, K. E., and Filer, L. J., Jr.:
Vitamin E (tocopherol) in human fetuses and
placentae. Biol. Neonat.. 1 :1, 1952.
12. Fee, B. A., and Weil, W. B., Jr. : Body composition
of infants of diabetic mothers determined by
di-rect analysis. Ann. N. Y. Acad. Sci., 110:869,
1963.
13. Meeh, K. :Oberfiachenmessungen des menschlichen
K#{246}rpers:Z. Biol., 15:425, 1879.
14. Lissauer, W.: Uber Oberfiachenmessungen an
Sauglingen und ihre Bedeutung f#{252}rden
Nah-rungsbedarf. Jahrb. Kinderheilk. 58:392, 1903.
15. Tanner, J. M.: Fallacy of per-weight and
per-sur-face area standards, and their relation to spurious
correlation. J. Appi. Physiol., 2:1, 1949.
16. Weil, W. B., Jr.: Chemical composition of the fetus.
in Barnett, H. L., ed: Pediatrics, ed. 14. New
York: Appleton-Century-Crofts, in press.
17. Benedict, F. G., and Talbot, F. B.: The Gaseous
Metabolism of Infants. Washington, D. C.:
Carnegie Institution, 1914.
18. Krogh, A.: The Respiratory Exchange of Animals
and Man. London: Longmans Green, 1916.
19. Kleiber, M.: Body size and metabolic rate. Physiol.
Rev., 27:511, 1947.
20. Hemmingsen, A. M. : The relation of standard
(basal) energy metabolism to total fresh weight of living organisms. Report of Steno Memorial Hospital and the Nordisk Insulin Laboratorium IV. Copenhagen, 1950.
21. Behnke, A. R., Osserman, E. F., and Welliain,
w.
C.: Lean I)ody mass: its clinical significanceand estimation from excess fat and total body water determinations. Arch.
mt.
Med., 91:585,1953.
22. Moore, F. D., Olesen, K. H., McMurrey, J. I).,
Parker, H. V., Ball, M. H., and Boyden, C. M.:
The Body Cell Mass and its Supporting En-vironment. Philadelphia: W. B. Saunders Co.,
1963.
23. Talbot, F. 13., and Sisson, W. it. : Basal metabolism
in relation to body surface at different ages with special reference to prematurity. Proc. Soc. Exper. Biol. Med., 19:309, 1922.
24. Talbot, F. B., Sisson, W. R., Moriarity, M. E., and
Dalrymple, A. J. : Basal metabolism of
prenlatur-ity II. Relation of basal metabolism to caloric
in-take and weight curve. Amer. J. Dis. Child.,
24:95, 1922.
25. Talbot, F. B., Sisson, W. R., Moriarity, M. E., and
Dairymple, A. J.: Basal metabolism of prematur-ity III. Metabolism findings in twenty-one
pre-mature infants. Amer. J. I)is. Child., 26:29, 1923.
26. Dawkins, M. J. R., and Hull, I).: Brown a dipose
tissue and non-shivering thermogenesis in
new-born animals. in J. H. P. Joaxis, 11. K. A. Visser, J. A. Troelstra, ed.: Nutricia Symposium in
The Adaptation of the Newborn Infant to
Extra-uterine Life. Leiden: H. E. Stenfert Kroese,
p. 269, 1964.
27. Hull, D. : Structure and function of brown adipose
tissue. Brit. Med. Bull., 22:92, 1966.
Acknowledgment
It is a pleasure to thank Dr. Ralph B. Dell for math.
