Identification of an indirect, rapid means to measure total body water (TBW) during space flight may aid in quantifying hydration status and assist in countermeasure development. Bioelectrical response testing and hydrostatic weighing were performed on 27 subjects who ingested O-18, a naturally occurring isotope of oxygen, to measure true TBW. TBW estimates from three bioelectrical response prediction equations and fat-free mass (FFM) were compared to TBW measured from O-18. A repeated measures MANOVA with post-hoc Dunnett's Test indicated a significant (p less than 0.05) difference between TBW estimates from two of the three bioelectrical response prediction equations and O-18. TBW estimates from FFM and the Kushner & Schoeller (1986) equation yielded results that were similar to those given by O-18. Strong correlations existed between each prediction method and O-18; however, standard errors, identified through regression analyses, were higher for the bioelectrical response prediction equations compared to those derived from FFM. These findings suggest (1) the Kushner & Schoeller (1986) equation may provide a valid measure of TBW, (2) other TBW prediction equations need to be identified that have variability similar to that of FFM, and (3) bioelectrical estimates of TBW may prove valuable in quantifying hydration status during space flight

Barrows, Linda H.

Inners, L. Daniel

Klein, Peter D.

Siconolfi, Steven F.

Stricklin, Marcella D.

Wong, William W.

English

NASA Technical Reports Server

NASA
Technical
Paper
3299
1993
National Aeronautics and
Space Administration
Office of Management
Scientific and Technical
Information Program
Comparison of Total Body
Water Estimates From 180
and Bioelectrical Response
Prediction Equations
Linda H. Barrows,
L. Daniel Inners,
and Marcella D. Stricklin
KRUG Life Sciences
Houston, Texas
Peter D. Klein
and William W. Wong
Children's Nutrition Research Center
at Baylor College of Medicine
Houston, Texas
Steven F. Siconolfi
Lyndon Bo Johnson Space Center
Houston, Texas
https://ntrs.nasa.gov/search.jsp?R=19930014545 2020-03-17T06:56:06+00:00Z

CONTENTS
Page
INTRODUCTION ................................................................... 1
METHODS ......................................................................... 1
RESULTS .......................................................................... 4
CONCLUSION ..................................................................... 6
REFERENCES ..................................................................... 6
o°.
III
pR_a_l_D_l_i3 P_E BL._,t"_IK ,',lOT FILMED
i
12
3
TABLES
Subject characteristics (mean +__SD) ...........................................
Bioelectrical response prediction equations used to estimate TB W ..................
Total body water estimates from three bioelectrical response prediction
equations and hydrostatically derived FFM compared to total
water measured from 180 (n = 27) ..........................................
Page
1
3
4
FIGURES
Bioelectrical resistance test conducted in the supine position. Electrodes
being used for measuring--found on the subject's right hand and left
foot--are covered with cloth to keep the temperature constant ................
Hewlett-Packard Precision LCR meter and YSI skin temperature
probe apparatus ..........................................................
Body volume determination by hydrostatic weighing using a
snorkel-like device and tidal breathing .....................................
Comparison (mean __ SD) of TBW prediction methods with 180 ...................
2
3
4
5
iv
INTRODUCTION
Measurement of total body water (TBW)
during extended-duration spaceflight may be
performed to evaluate exercise and cardiovas-
cular countermeasures to microgravity-induced
deconditioning. Quantification of TBW can be
performed through the use of water enriched
with a stable isotope of oxygen, 180 [1,2]. A sam-
ple of H21aO is ingested orally and, after 3 to 5
hours of equilibration with the body's water
compartments, saliva samples are obtained to
measure H2180 dilution. This method of TBW
measurement is noninvasive, requires little ef-
fort on the part of the subject, and has a preci-
sion of 0.8-1.5% when compared to serum sam-
ples [1]. Traditionally, isotope dilution using
deuterated (2H20} or tritiated (3H20) water has
been used as the reference for TBW measure-
ment. Use of deuterated water, however, can
cause metabolic side effects when given in high
doses; and tritiated water is radioactive, which
limits its use in many circumstances. Analysis
of hydrogen isotope dilution also requires use of
very precise and expensive spectrometric equip-
ment [2]. Finally, hydrogen isotopes can overes-
timate the TBW measurement due to hydrogen
exchange with protein. The use of 180, a natu-
rally occurring stable isotope of oxygen, is much
more desirable than the use of hydrogen iso-
topes; but it is not without drawbacks, which
are: (1) expensive generation ($500-$1000/dose),
(2) limited availability (i.e., approximately 1
year to obtain), and (3) need for costly spectro-
metric analyzers to evaluate the saliva samples.
For these reasons, many clinical and research
facilities estimate TBW indirectly through hy-
drostatic weighing techniques. Total body im-
mersion is used to calculate the body density
from which percent body fat and fat-free mass
(FFM) are derived. TBW represents a fixed frac-
tion (73.2%) of FFM [7].
Bioelectrical responses have been shown to
estimate human body composition accurately
[3-6]. Bioelectrical response devices measure
resistance (R) and reactive capacitance (reac-
tance) responses to an excitation current of 800
IJA at a signal frequency of 50-120 kHz. The
subthreshold current is applied through elec-
trodes at the wrist and ankle, and bioelectrical
measurements are made immediately. A clear
linear relationship (r = -0.86) exists between
TBW (from deuterium-labeled water} and bio-
electrical resistance [5]. This relationship is
strengthened when TBW is correlated with
height (Ht) and bioelectrical resistance (R) in
the factor Ht2/R [3,5].
Numerous prediction methods exist for esti-
mating body composition and TBW. Identifica-
tion of a method that is rapid, accurate, and
cost-effective is necessary so that the procedure
may be used during extended-duration space-
flight to monitor countermeasure therapy. The
purpose of this investigation was to compare
TBW estimates from three established bioelec-
trical response prediction equations [2,3,8] with
two standard methods--hydrostatically derived
FFM and 180.
METHODS
Twenty-seven subjects (14 females and 13
males) were recruited through the NASA Health
Screening Facility at the NASA/Johnson Space
Center and gave written informed consent to
participate in the study (Table 1).
TABLE 1. Subject characteristics (mean __ SD)
n
Mean Age (yr)
Mean Height (cm}
Mean Weight (kg)
Mean Body Fat (%)
27
32
168.5
67.8
21.0
_+ 6
+_ 6.0
_+ 12.2
_+ 6.7
All testingwascompletedbetween7:00a.m.
and 1:00p.m.on the sameday. Subjectswere
askedto fast for at least4 hours,with nocon-
sumptionof caffeineor alcoholwithin 24hours
of testing. Uponarrival, a backgroundsaliva
samplewascollectedto establishexistinglevels
of 180in thebody. Subjectsthenweregivena
bagelandjuice prior to ingesting 40-45g of
H2180(6-7gof 180).Toensurethat theentire
amountof 180wasingested,thebottlecontain-
ing the H2180wasrinsedtwicewith approxi-
mately50mLof tapwaterandwasgivento the
subjectto drink. Subjectsthen gaveapproxi-
mately5 mLof salivaat 3,4, and5 hoursafter
initial H2180consumption. Saliva samples were
immediately frozen and later analyzed by the
Stable Isotope Laboratory, Children's Nutrition
Research Center at the Baylor College of
Medicine.
Bioelectrical response testing was complet-
ed between the 3- and 4-hour 180 saliva collec-
tion times. Skin sites on the distal surface of the
metacarpals and metatarsals, between the me-
dial and lateral malleoli of the ankle, and be-
tween the distal prominences of the radius and
ulna, were cleansed with alcohol before applying
four silver/silver chloride ECG electrodes (Fig.
1).
Tetrapolar bioelectrical resistance readings
were taken immediately upon resuming the
supine position, and measurements were made
of the subject's right side. Bioelectrical resis-
tance responses to input frequencies of 50-300
kHz were simultaneously obtained from a modi-
fied 4284A Hewlett-Packard Precision LCR
Meter (Fig. 2).
Three bioelectrical response prediction equa-
tions were used to estimate TBW (Table 2).
FIG. 1. Bioelectrical resistance test conducted in the supine position. Electrodes
being used for measuring--found on the subject's right hand and right foot--are
covered with cloth to keep them temperature constant.
2
CYR1GINAL PAGE
BLACK AND WHITE PH'OT_3'RAPH
riG. 2. Hewlett-Packard Precision LCR meter and YSI skin temperature probe
apparatus.
TABLE 2. B ioelectrical response prediction equations used to estimate TB W
1o
,
.
Lukaski & Bolonchuk [4]
TBW (L) = 0.337 • (Ht2/R) + 0.14 • Wt- 0.08 • Age+2.9 • Gender+4.65
where R at 50 kHz
Gender: Male = 1, Female = 0
Kushner & Schoeller [3]
Males: TBW (L) = 0.396" (Ht2/R}+ 0.143 • Wt+8.399
Females: TBW (L) = 0.382 • (Ht2/R)+0.105 • Wt+8.315
where R at 50 kHz
Segal et al. [81
TBW (L) = 3.43+0.14 • Wt+0.45 • (Ht2/R)
where R at 100 kHz
Body density determination through hydro-
static weighing was conducted immediately
after ingesting the H2180. Each subject was com-
pletely submerged in a tank of water (30-35°C)
and was allowed to perform normal tidal breath-
ing through a snorkel-like device (Fig. 3).
Ten maximal exhalations were performed,
at which time weights were recorded. Body vol-
ume was corrected for lung residual volume us-
ing an oxygen dilution technique [9] that was
performed at the end of the test period. Percent
body fat [10], FFM, and TBW (73.2% of FFM}
were then calculated from body density using a
two-compartment model.
TBW (kg) mean, standard deviation (SD),
and standard error of estimate as a percent of
the 180 mean (SEE), were calculated for TBW
measurements from 180, FFM from hydrostatic
weighing, and the three bioelectrical response
prediction equations {Table 2). Pearson prod-
uct-moment correlation coefficients (r) were cal-
culated to determine the relationship between
each method and 180. A repeated measures
MANOVA with post-hoc Dunnett's Test was us-
ed to determine significant differences between
bioelectrical response prediction and 180.
RESULTS
The equation from Segal et al. [8] yielded
mean TBW estimates that were significantly
(p < 0.05) greater than the mean TBW
measurement given by 180. The bioelectrical
response prediction equation from Lukaski &
rzG. 3. Body volume determination by hydrostatic weighing using a
snorkel-like device and tidal breathing
_T"dGtNAL P.AGE
13L#IICK A.ND WHITE P,H_S)TOG',_ApN
4
Bolonchuk [4] significantly (p < 0.05) under-
predicted TBW. TBW estimates from FFM and
the bioelectrical response prediction equation of
Kushner & Schoeller [3] were not significantly
(p > 0.05} different than those given by 180
(Table 3, Fig. 4). Standard errors identified
through regression analyses were, however,
higher for all bioelectrical response prediction
equations when compared to those derived from
FFM (Table 3). Strong correlation coefficients
were found between each prediction method and
180.
Findings reported here are for all subjects
combined (Table 3). When the findings for
males (n = 13) and females (n = 14) were
analyzed separately, the mean, SD, SEE, and r
were altered but statistical findings were un-
changed. Results are, therefore, presented for
all 27 subjects.
TABLE 3. Total body water estimates from three bioelectrical response prediction equations
and hydrostatically derived FFM compared to total water measured from 180 (n = 27)
Method Mean SD r SEE (%)
180 39.29 7.31 ....
FFM 39.16 7.44 0.98 3.5
Kushner & Schoeller [3] 39.81 7.96 0.93 6.7
Lukaski & Bolonchuk [4] 32.81" 7.09 0.94 6.4
Segal et al. [8] 41.56" 8.22 0.93 7.2
*Significantly, (p < 0.05) differs from 180.
45
0
180 FFM K & S L & B
FIG. 4. Comparison {mean _+ SD_ of TBW prediction methods
with taO
Segal
CONCLUSION
Bioelectricalresponsetestingrequiresmin-
imal equipmentandeffort,andproducesresults
quickly. If accurate,this methodwouldbeideal
for useduringspaceflighto monitorhydration
statusandperhapsimprove countermeasure ap-
plication and orthostatic tolerance upon return
to one-g. The bioelectrical response prediction
equation from Kushner & Schoeller [3) provided
the most valid measure of TBW in this study
when compared to the reference value given by
180. The Kushner & Schoeller equation, unlike
the other two bioelectrical response prediction
equations examined, uses separate numerical
constants depending upon gender. All three
prediction equations had greater variability in
measuring TBW than that found with FFM,
which is commonly used in laboratories as a ref-
erence to assess body composition (Table 3). It
is suggested that, before using the impedance
method to measure TBW during spaceflight,
other bioelectrical response prediction equations
with lower variability should be identified.
REFERENCES
[11 SCHOELLER, D. A., W. DIETZ, E. VAN
SANTEN, AND P. D. KLEIN. Validation of
saliva sampling for total body water deter-
mination by H2180 dilution. Am. J. Clin.
Nutr. 35:591-4, 1982.
[21 SCHOELLER, D. A., E. VAN SANTEN, D. W.
PETERSON, W. DIETZ, J. JASPAN, AND P. D.
KLEIN. Total body water measurement in
humans with 180 and 2H labeled water.
Am. J.Clin.Nutr. 33:2686-93, 1980.
[31 KUSHNER, R. F. AND D. A. SCHOELLER.
Estimation of total body water by bioelec-
tricalimpedance analysis. Am. J. Clin.
Nutr. 44:417-24, 1986.
[4] LUKASKI, H. C. AND W. W. BOLONCHUK.
Estimation of body fluid volumes using
tetrapolar bioelectrical impedance mea-
surements. Avait. Space Environ. Med.
59:1163-69, 1988.
[5] LUKASKI, H. C., P. R. JOHNSON, W. W.
BOLONCHUK, AND G. I. LYKKEN. Assess-
ment of fat-freemass using bioelectrical
impedance measurements of the human
body. Am. J. Clin.Nutri. 41:810-17, 1985.
[6]
[7]
[81
[91
[101
LUKASKI, H. C., W. W. BOLONCHUK, C. B.
HALL, AND W. A. SIDERS. Validation of
tetrapolar bioelectrical impedance method
to assess human body composition. J. Appl.
Physiol. 60(4):1327-32, 1986.
LUKASKI, H. C. Methods for the assessment
of human body composition: Traditional
and new. Am. J. Clin. Nutr. 46:537-56,
1987.
SEGAL, K. R., S. BURASTERO, A. CHUN, P.
CORONEL, R. N. PIERSON, AND J. WANG.
Estimation of extracellular and totalbody
water by multiple-frequency bioelectrical-
impedance measurement. Am. J. Clin.
Nutr. 54:26-29, 1991.
WILMORE, J. R. A simplified method for
determination of residual lung volumes. J.
Appl. Physiol. 27:96-100.
BROZEK, J. F., J. T. GRANDE, AND A.
ANDERSON. Densitometric analysis ofbody
composition: Revision of some quantitative
assumptions. Ann. NY Acad. Sci. 10:113-
40, 1963.

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4. TITLEANDSUBTITLE S. FUNDING NUMBERS
Comparison of TotalBody Water EstimatesFrom 180 and Bioelectrical
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6. AUTHOR(S)
Linda H. Barrows, L. Daniel Inners, Marcella D. Stricklin.
Peter D. Klein. William W. Wong. and Steven F. Siconoifi
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National Aeronautics and Space Administration
Lyndon B. Johnson Space Center
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Barrows, lnners, and StrickEn: KRUG Life Sciences, Houston. TX:
Klein and Wong: Children's Nutrition Research Center at Baylor College of Medicine, Houston, TX:
Siconolfi: Lyndon B. Johnson Space Center, Houston, TX.
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13 ABSTRACT(Maximum 200 words)
Identification of an indirect, rapid means to measure total body water (TBW) during spaceflight may aid in
quantifying hydration status and assist in countermeasure development. Bioelectrical response testing and
hydrostatic weighing were performed on 27 subjects who ingested 180, a naturally occurring isotope of oxygen, to
measure true TBW. TBW estimates from three bioelectrical response prediction equations and fat-free mass (FFM)
were compared to TBW measured from 1$O. A repeated measures MANOVA with post-hoc Dunnett's Test indicated
a significant (p < 0.05) difference between TBW estimates from two of the three bioelectrical response prediction
equations and 180. TBW estimates from FFM and the Kushner & Sehoeller (1986) equation yielded results that
were similar to those given by 180. Strong correlations existed between each prediction method and lsO; however,
standard errors, identified through regression analyses, were higher for the bioeleetrieai response prediction
equations compared to those derived from FFM. These findings suggest (1} the Kushner & Schoeller (1986)
equation may provide a valid measure of TBW, (2) other TBW prediction equations need to be identified that
have variability similar to that of FFM, and (3) bioelectrical estimates of TBW may prove valuable in quantifying
hydration status during spaceflight.
14. SUBJECTTERMS
body fluids,totalbody water (TBW); bioelectricity,bioelectricresponse prediction
equations; adipose tissues,fat-freemass (FFM)
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Comparison of total body water estimates from O-18 and bioelectrical response prediction equations

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