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Appendicular skeletal muscle mass: Measurement by dual-photon absorptiometry


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Dual-photon absorptiometry (DPA) allows separation of body mass into bone mineral, fat, and fat-free soft tissue. This report evaluates the potential of DPA to isolate appendages of human subjects and to quantify extremity skeletal muscle mass (limb fat-free soft tissue). The method was evaluated in 34 healthy adults who underwent DPA study, anthropometry of the limbs, and estimation of whole-body skeletal muscle by models based on total body potassium (TBK) and nitrogen (TBN) and on fat-free body mass (FFM). DPA appendicular skeletal muscle (22.0 +/- 3.1 kg, mean +/- SD) represented 38.7% of FFM, with similar proportions in males and females. There were strong correlations (all p less than 0.001) between limb muscle mass estimated by DPA and anthropometric limb muscle areas (r = 0.82-0.92), TBK (r = 0.94), and total-body muscle mass based on TBK-FFM (r = 0.82) and TBK-TBN (r = 0.82) models. Appendicular skeletal muscle mass estimated by DPA is thus a potentially practical and accurate method of quantifying human skeletal muscle mass in vivo.
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214 Am J C/in Nuir I990;52:214-8. Printed in USA. © 1990 American Society for Clinical Nutrition
Appendicular skeletal muscle mass: measurement
by dual-photon absorptiometry”2
Steven B Heymsfield, Rebecca Smith, Mary Aulet, Brooke Bensen,
Steven Lichtman, Jack Wang, andRichardNPierson, Jr
ABSTRACT Dual-photon absorptiometry (DPA) allows
separation of body mass into bone mineral, fat, and fat-free
soft tissue. This report evaluates the potential ofDPA to isolate
appendages ofhuman subjects and to quantify extremity skele-
tal muscle mass(limb fat-free soft tissue). The method was eval-
uated in 34 healthy adults who underwent DPA study, anthro-
pomety of the limbs, and estimation of whole-body skeletal
muscle by models based on total body potassium (TBK) and
nitrogen (TBN) and on fat-free body mass (FFM). DPA appen-
dicular skeletal muscle (22.0 ±3. 1 kg, I ± SD) represented
38.7% of FFM, with similar proportions in males and females.
There were strong correlations (all p<0.00 1)between limb
muscle mass estimated by DPA and anthropometric limb mus-
cle areas (r =0.82-0.92), TBK (r =0.94), and total-body mus-
cle mass based on TBK-FFM (r =0.82) and TBK-TBN (r
=0.82) models. Appendicular skeletal muscle mass estimated
by DPA is thus a potentially practical and accurate method of
quantifying human skeletal muscle mass in vivo. Am J
Clin Nutr 1990;52:2 14-8.
KEY WORDS Body composition, dual-photon absorpti-
ometry, skeletal muscle mass, neutron-activation analysis
Skeletal muscle represents the largest fraction of fat-free
body mass. Depending on gender, age, and health status, be-
tween one-third and one-half of total body protein is within
skeletal muscle (1).
Despite the obvious significance ofskeletal muscle to physi-
ology and nutrition, methods ofquantification in vivo remain
limited. Although two metabolic end products released from
myocytes, creatinine and 3-methyihistidine, have been used to
estimate whole-body muscle mass, their application is beset
with problems (2, 3). Long urine-collection intervals, the need
for appropriate dietary intake, and concerns related to the met-
abolic origin and distribution of 3-methylhistidine and creati-
nine limit the use ofboth ofthese methods.
At present the most widely accepted methods of evaluating
skeletal muscle mass involve computerized axial tomography,
magnetic-resonance imaging, and ultrasonography performed
in multiple sections ofthe body. Although these methods repre-
sent a technological advance, expense, radiation exposure, urn-
ited instrument access, and concerns for accuracy are often
cited as limitations ofone or the other techniques (4).
The recent development of dual-photon absorptiometry
(DPA) presents a new opportunity to quantify skeletal muscle
mass in vivo. Long recognized for its effectiveness at measuring
bone density, the newly appreciated ability ofDPA to measure
fat and lean components presents an equally significant prom-
ise to the field of body composition research. Because of the
growing number of available whole-body instruments, ex-
tremely low radiation exposure, and ability to define total ap-
pendicular skeletal muscle and bone mass with high precision
(5, 6), these measurements will be widely applicable. Accord-
ingly, in this report we describe the theory behind the use of
DPA in estimating appendicular skeletal muscle mass, the cali-
bration data, and the results ofinitial patient studies.
Whole-body DPA partitions body weight into two fractions,
bone ash (calcium hydroxyapatite) and soft tissue, by measur-
ing differential attenuation of photons at two energy levels.
These photons may be produced by ‘53Gd or by an x-ray
source, and the underlying principle is identical in both cases.
The DPA algorithm includes a measure of soft-tissue attenua-
tion at the two energy levels referred to as the R. The R.,.
correlates linearly with the proportion of soft tissue as fat (or
lean). The fat content ofscanned soft tissue in vivo can be esti-
mated by means of a calibration equation (6). This is accom-
plished by first scanning phantoms of known fat content and
establishing the prediction equation for percent fat based on
R5T .Chemically analyzed beefphantoms are used for this pur-
pose. Typical regression lines during calibration are r=0.96-
0.98 (6, 7). In an earlier study we described this calibration pro-
cedure and demonstrated excellent agreement between fat esti-
mated by DPA in healthy nonobese subjects and fat deter-
mined by such conventional methods as hydrodensitometry
CFrom the Department of Medicine, Obesity Research Center, St
Luke’s-Roosevelt Hospital Center, Columbia University College of
Physicians and Surgeons, New York.
2Address reprint requests to SB Heymsfield, Weight Control Unit,
4 1 1 West 1 14th Street, New York, NY 10025.
ReceivedJune 16, 1989.
Accepted for publication October 1 1, 1989.
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(r =0.94, SEE =1 .82 kg) and neutron-activation analysis
(r =0.95, SEE =1 .68 kg) (6). Hence a given DPA scan, or any
subregion ofa scan, can be analyzed for bone ash, nonosseous
lean tissue, and fat.
The extremities consist primarily of three components-
skeleton, skeletal muscle, and fat. The skeleton or bone shaft
contains a small amount of marrow, which for simplicity may
be ignored in the evaluation of limb composition. We also as-
sume that skin and associated subcutaneous tissue are negligi-
ble in mass relative to the skeletal-muscle component. The de-
fatted and marrow-free bone is a mixture ofwater, protein, and
minerals (ash). Under usual circumstances ash represents 55%
ofwet skeletal weight, with mineral content decreasing slightly
(50-52%) in osteoporotic patients (8, 9). A reasonable assump-
tion, therefore, is that wet bone weight equals bone ash divided
by 0.55 or multiplied by 1.82.
Limb fat is estimated through use ofthe R5T and beef phan-
toms as described above. The actual fat mass in the limb is
determined as percent fat multiplied by soft-tissue mass. Skele-
tal muscle mass is then equal to total limb mass minus the sum
oflimb fat and bone mass.
Upon completion ofthe scan, the DPA software generates an
image ofthe subject’s skeleton (Fig I). Using specific anatomic
landmarks and a cursor, the DPA operator isolates the legs and
arms as shown in Figure 1.Once isolated, the system software
provides the total mass, RST, and bone ash for the identified
region. Wet bone mass (bone ash X 1.82) is next subtracted
from total limb mass, followed by subtraction offat mass calcu-
lated from the RST calibration line. This result then represents
skeletal muscle mass either separately for each limb or for the
summed upper- and lower-limb muscle masses.
The DPA muscle-mass method was evaluated in 34 healthy
subjects who underwent DPA, anthropometry, whole-body
counting for total body potassium (TBK), and prompt ‘y-neu-
tron-activation analysis for total body nitrogen (TBN). Four
of the subjects underwent the DPA study on 4 (n =2) or 5
(n =2) consecutive days to establish the between-day coeffi-
cient of variation (CV) for estimates of limb composition. A
single trained observer (RS) read all 34 initial DPA scans and
the serial CV studies were interpreted by investigator MA. A
portion of this database is presented in two earlier unrelated
protocols (6, 10). Each volunteer signed an informed consent
before the study, which was approved by the institutional re-
view boards at St Luke’s-Roosevelt Hospital and at Brookha-
yen National Laboratory.
Dual-photon absorptiometrv. Awhole-body DPA scanner
(DP4, Lunar Radiation, Madison, WI) was used to evaluate
each patient’s total and regional bone ash, RST, and soft-tissue
mass. Each head-to-toe scan required -‘-55 mm. For calibra-
tion, seven frozen beef phantoms of known fat content were
scanned and the results were used to relate R5T to percent fat
(6). The aforementioned procedures were then used to derive
whole-body and appendicular bone ash, fat, and skeletal mus-
cle. The between-day CV for bone ash and percent fat are 1.0%
and 1 .7%, respectively (6). The radiation exposure is 0.02 mGy
per scan.
Total bodi’ potassium. Whole-body #{176}Kcounting was used
to derive TBK ( 1 1). The Brookhaven system consists of 54 so-
dium iodide detectors placed above and below the patient. The
FIG I.Reconstruction of DPA scan demonstrating landmarks that
subdivide body into six regions. The neck cut is made just below the
chin. The rib cuts are made as close to, but not touching, the spine. The
arms are isolated by running a line through the humeral head. The
pelvis cut is placedjust above the pelvic brim and the system computer
automatically draws the lower pelvic lines. The spine cut is placed just
below the last pair ofribs coming out ofT 12.
CV for TBK whole-body counting is 2.4%. The system opera-
tion was described in detail previously (1 1).
Total body nitrogen. Prompt -y-neutron-activation analysis
was used to estimate TBN. This system, described by Vartsky
et al (I 2), uses a plutonium-beryllium source of neutrons that
activates ‘4N nuclei. The 1 735 0prompt y decay of activated
nitrogen is then detected by two sodium iodide crystals that are
mounted above the patient. The present system has a CV of
2.4% in nitrogen-containing phantoms. Additional details of
prompt gamma TBN analysis are reviewed in references 12
and 13.
The absolute TBK and TBN were correlated directly against
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Subject characteristics and baseline body composition results*
Age Weight Body mass
index Fat
3. kg kg/rn? %
Females(n =16) 56.3 ±22.6 59.7 ± 10.2 22.4 ± 2.9 31.7 ±6.8
Males(n= 18) 48.7± 15.9 72.7± 10.3 23.7±2.9 21.4±6.5
Total(n =34) 52.3 ±19.7 66.6 ±12.1 23.1 ±2.8 26.3 ±8.4
S  SD.
muscle mass estimated by DPA. In addition, total-body skele-
tal muscle mass was calculated by two equations proposed by
Burkinshaw (14, 15). In the first model, skeletal muscle mass
(5MM, kg) is determined by simultaneous measurement of
TBK (mmol) and TBN (g) by use ofthe following relation:
5MM =(TBK -1.33 TBN)/51.2
This model assumes that K/N in skeletal muscle and nonskele-
tal muscle lean tissue is 9 1 and 47 mmol/kg, respectively. The
second model replaces TBN with fat-free body mass(FFM, kg).
Our approach in this study was to use the equation
SMM - (TBK - 48 FFM)/43
in which FFM was calculated as body weight minus DPA total
body fat.
Anthropometric measurements. The anthropometnc mus-
cle-plus-bone area was calculated for upper midarm and mid-
thigh from respective circumference and skinfold measure-
ments. A single trained observer made all ofthe measurements
on the right side of standing patients (14). Midarm and mid-
thigh were identified as being halfway between the acromial
and olecranon processes ofthe scapula and the inferior margin
ofthe ulna and the inguinal crease and proximal border of the
patella, respectively. A calibrated tape measure was used to es-
tablish limb circumferences at each location. The triceps skin-
fold was then measured at the posterior aspect of the upper
midarm, and the results ofthree trials were averaged. The thigh
skinfold was measured at the circumference site in the midsag-
gital plane on the anterior aspect of the thigh. Limb muscle-
plus-bone area was then calculated as
[(circumference) - (ir X skinfoid)]2/4ir
where all units are in centimeters (16).
Statistical methods
Correlations between muscle mass and other body composi-
tion estimates were examined by using simple linear-regression
analysis (Statst, Statsoft, Tulsa, OK). All group results are ex-
pressed as mean ± SD.
There were 18 male and 16 female subjects (Table I) with
average age for the pooled group of52.3 ±19.7 (i± SD). Over-
all the group was relatively lean, with a body mass index of 23
±2 kg/rn2 and a percentage fat by DPA for men and women
of2l.4 ± 6.5% and 31.7 ± 6.8%, respectively.
DPA limb composition
(1) The repeated studies on four ofthe subjects resulted in CVs
of7.0 ± 2.4%, 2.4 ± 0.5%, and 3.0 ± 1.5% (1± SD) for upper-
extremity, lower-extremity, and combined-limb appendicular
skeletal muscle masses, respectively.
The bone, skeletal muscle, and fat content of the limbs as
estimated by DPA is presented in Table 2. Males had more
bone and skeletal muscle and less fat than did females for both
lower and upper extremities. Males also had more upper-ex-
tremity than lower-extremity skeletal muscle (upper/lower
=0.57) than did females (0.44). The ratio of bone to skeletal
muscle tended to be higher for both upper and lower extremi-
ties in males (0.089 and 0.142) than in females (0.085 and
0. 1 18) and more bone was present relative to skeletal muscle
in lower(pooled value =0. 135) than upper(0.094) extremities.
Skeletal muscle mass
No definitive methods are available for quantifying whole-
body skeletal muscle mass in vivo. DPA was therefore evalu-
ated in relation to available markers of skeletal muscle by
simple linear-regression analysis. The results ofTBK and TBN
estimates are presented in Table 3 along with calculated total-
body skeletal muscle mass (TBK, TBN, and FFM), anthropo-
metric limb muscle areas, and combined (upper and lower)
DPA limb muscle mass.
TBK was highly correlated with DPA extremity muscle mass
(3) fl pooled data for the 34 subjects (r =0.94, p<0.001 ; Table 4
and Fig 2). The correlation between DPA muscle and TBN
was also significant (r =0.78, p<0.001) and ofsimilar magni-
Limb composition analyses from dual-photon absorptiometry*
Lower extremities Upper extremities
Bone Skeletal muscle Fat Total Bone Skeletal muscle Fat Total
kg kg
3.7± 1.6
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2000 3000 4000 5000
*Calculated from TBK and TBN.
tCalculated from TBK and FFM.
Results ofbody composition studies*
mmo/ kg kg kg cm cm2 cm2 kg
Females 2152±394 1.35±0.27 7.0± 5.9 5.0±4.6 31.9± 5.8 136.6±28.6 168.3±31.4 15.7±2.9
Males 3459±578 1.78±0.25 21.4± 8.0 17.1 ±7.1 57.6± 9.5 169.5±28.0 227.1 ±36.3 22.0±3.2
Total 2844±823 1.58±0.34 14.6± 10.1 11.4±8.6 45.5± 15.1 154.0±32.7 199.3±44.9 19.0±4.3
*SMM I, SMM2, and SMM3 are skeletal muscle mass calculated from, respectively, TBK and TBN (Eq 1), TBK and FFM (Eq 2), and the sum
ofupper and lower extremity 5MM estimated by DPA (Eq 3). AMA is arm muscle-plus-bone area; TMA is thigh muscle-plus-bone area.
tude to the correlation between DPA muscle and body weight
(r =0.80, p<0.001).
Total body estimates of skeletal muscle mass (Eqs 1 and 2)
were on average smaller than limb muscle mass estimated by
DPA (I 4.6 and 1 1 .4 kg, respectively, vs 19.0 kg). Although sev-
eral negative values were observed in the former, both calcu-
lated muscle estimates were significantly correlated with DPA
skeletal muscle (both r=0.82, p<0.00 1; Table 4).
Anthropometric muscle-plus-bone areas were significantly
(p <0.001) correlated with DPA extremity muscle mass, with
r=0.82 for upper limb r=0.88 for lower limb, and r=0.92
for the sum of upper- plus lower-limb muscle-plus-bone areas.
Thus two ofthe indirect markers ofskeletal muscle mass, TBK
and anthropometric muscle-plus-bone areas, were highly cor-
related with DPA muscle mass. Significant but weaker associa-
tions were observed between DPA muscle and whole-body
skeletal muscle derived by the TBK-TBN and TBK-FFM
Despite the obvious physiological relevance of quantifying
skeletal muscle mass, no definitive whole-body in vivo method
is yet available. The DPA technique described herein advances
our measurement capability by providing a practical approach
to estimating appendicular skeletal muscle mass. The extrem-
ity muscle per se is of intense interest and, moreover, the ap-
pendages account for a large portion (73-75%) oftotal skeletal
Correlations between DPA appendicular skeletal muscle and other
body composition estimates
Equation rSEE p
Body weight 0.29x +0.0 0.80 2.7 <0.001
TBK 0.005x +5.01 0.94 1.6 <0.001
TBN l0.06x+ 3.14 0.78 2.8 <0.001
Skeletal muscle I  0.35x +1 3.83 0.82 2.6 <0.001
Skeletal muscle 2t 0.41x +14.33 0.82 2.6 <0.00 1
Arm muscle-plus-bone
area 0.24x +8.25 0.82 2.5 <0.001
Thigh muscle-plus-bone
area 0.l2x+ 1.04 0.88 2.1 <0.001
Arm +thigh muscle-
plus-bonearea 0.09x+ 1.33 0.92 1.8 <0.001
muscle mass (17). The between-day CV for the method (3%
for total extremity muscle) is within the range of other body
composition techniques, such as whole-body counting for po-
tassium. Hence the DPA approach brings within range the ca-
pability of reproducibly estimating all but one-fourth of skele-
tal muscle mass.
Skeletal muscle mass derived by DPA was highly correlated
with other regional (anthropometry) and total-body (whole-
body counting, neutron activation) estimates of muscle mass.
These associations demonstrate the potential of using DPA to
explore other methods ofquantifying muscle. For example, the
sum ofanthropometric limb muscle-plus-bone areas showed a
strong correlation (r =0.92) with DPA total-extremity muscle
mass, suggesting the potential for developing anthropometric
limb-muscle-mass prediction equations. Another example is
the demonstration that the neutron-activation and the whole-
body counting models (Eqs 1 and 2) for partitioning FFM into
muscle and nonmuscle components provides muscle estimates
that on average are too low (1 1-15 kg vs 19 kg for DPA limb
muscle), with negative values observed in some cases. These
models therefore need to be reconsidered and perhaps revised
in light ofthe present findings.
The DPA skeletal-muscle-mass method has several possible
limitations worthy of discussion. At present our gadolinium
system has a long scan time (55 mm), restricting the study to
patients with sufficient endurance. New x-ray-based dual-pho-
ton systems (DEXA) reduce scan time to 15 mm, thus par-
tially alleviating this problem. The minimal radiation doses are
<0.01 of 1% ofannual background, or ‘--2 h background mdi-
Skeletal Muscle
(kg) 20
10 -
FIG 2. DPA appendicular skeletal muscle mass vs total body potas-
sium (TBK). Thirty-four observations pooled for males (n =18) and
females (n =I6) (DPA skeletal muscle =0.005 TBK +5.0, SEE =I .6
kg. r=0.94, p <0.001).
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ation. An additional problem is that the method developed in
the present study includes bone marrow and skin in the esti-
mate of limb muscle mass. However, these contributions are
relatively minor because the amount of nonfat extremity mar-
row and skin found in healthy young adults averages 1.2 kg, or
<5% of skeletal muscle as reported in this study (17). Finally,
changes in muscle hydration would alter the ratio between
muscle cell mass and total muscle weight, and this confounding
factor should be considered in the interpretation of results in
patients with edema.
In summary, we describe a promising new approach for esti-
mating the amount of skeletal muscle in the appendages. The
initial results in healthy adults indicate that limb muscle mass
determined by the DPA approach is highly correlated with
muscle estimates established by other available techniques. Fu-
ture studies are needed to evaluate the method’s applicability
in patients with altered body habitus and disease states. The
relative safety and low radiation exposure of the method and
the growing number and accessibility of available instruments
suggest that DPA may be a practical and widely applica-
ble technique of evaluating extremity skeletal muscle mass
invivo. II
1. Heymsfield SB, McManus C, Stevens V, Smith J. Muscle mass:
reliable indicator of protein-energy malnutrition severity and out-
come. Am J Clin Nutr l982;35: 1 192-9.
2. Heymsfield SB, Arteaga C, McManus C, et al. Measurement of
muscle mass in humans: validity ofthe 24-hour urinary creatinine
method. Am J Clin Nutr 1983; 37:478-93.
3. Buskirk ER, Mendez J. Lean body tissue assessment, with empha-
sis on skeletal muscle mass. In: Roche AF, ed. Body composition
assessments in youth and adults. Report ofthe Sixth Ross Confer-
ence on Medical Research. Columbus, OH: Ross Laboratories,
4. Heymsfield SB. Human body composition: analysis by computer-
ized axial tomography and nuclear magnetic resonance. In: Nor-
gan GN, ed. Proceedings of Euro-Nut Conference. The Hague:
CIP-Gegevens Konenkeijke Bibliotheek, 198:105-12.
S. Mazess RN, Peppler WW, Gibbons M. Total body composition
by dual-photon (‘53Gd) absorptiometry. Am J Clin Nutr l984;40:
6. Heymsfield SB, Wang J, Funfar J, Kehayias JJ, Pierson RN. Dual
photon absorptiometry: accuracy of bone mineral and soft tissue
mass measurement in vivo. Am J Clin Nutr 1989;49:1283-9.
7. WangJ, Heymsfield SB, Aulet M, Thornton JC, Pierson RN. Body
fat from body density: underwaterweighing vs dual photon absorp-
tiometry. Am J Physiol 1989;256:E829-34.
8. Woodard HQ. The composition ofhuman corticol bone. Clin Or-
thop 1964;37: 187-93.
9. Burnell JM, Baylink DJ, Chestnut CH III, Mathews MW, Teubner
El. Bone mineral and matrix abnormalities in post menopausal
osteoporosis. Metabolism 1982; 31:1 1 13-20.
10. Heymsfield SB, Wang J, Kehayias JJ, Heshka S, Lichtman S, Pier-
son RN Jr. Chemical determination of human body density in
vivo: relevance to hydrodensitometry. Am J Clin Nutr 1989; 50:
1 1. Cohn SH, Shukle KK, Dombrowski CS, Fairchild RG. Design and
calibration of “broad-beam” 238Pu, Be neutron source for total-
body neutron activation analysis. J Nucl Med 1972; 13:487-92.
12. Vartsky D, Ellis KJ, Cohn SH. In vivo quantification ofbody nitro-
gen by neutron capture prompt gamma-ray analysis. JNucl Med
l979;20:l 158-65.
13. Cohn SH, Vartsky D, Yasumura S, et al. Compartmental body
composition based on total body nitrogen potassium, and calcium.
Am J Physiol 1980;239:E524-30.
14. Burkinshaw L. Measurement ofhuman body composition in vivo.
In: Orton CG, ed. Progress in medical radiation physics. New
York: Plenum, 1985;2:l 13-37.
15. Burkinshaw L. Models ofthe distribution ofprotein in the human
body. In: Ellis KJ, Yasumura S, Morgan WD, eds. In vivo body
composition studies. London: Institute of Physical Sciences in
Medicine, 1987:15-24.
16. Wright RA, Heymsfield SB. Nutritional assessment. Boston:
Blackwell Scientific Publications, 1984.
17. Snyder WS, Cook Mi, Nasset ES, Karhausen LR, Howells GP,
Tipton IH, eds. Report ofthe task group on reference man. Oxford,
England: International Commission on Radiological Protection,
1984. (ICRP report 23.)
by guest on July 10, 2011www.ajcn.orgDownloaded from
... Total body mass was assessed using a digital scale (OS 180, Uranus), height was determined using a portable stadiometer (Sanny). The thigh muscle mass indicator assessed by AN was the right thigh perimeter corrected by right thigh skinfold (Fernández Vieitez et al., 2001;Frisancho, 1981;Heymsfield et al., 1990). The thigh perimeter was measured using a flexible metal anthropometric measuring tape (Cescorf), and the evaluator absolute technical measurement error presented was 0.3 cm (Perini et al., 2005). ...
... The anthropometric measurements followed protocol proposed by International Society for the Advancement of Kinanthropometry. The skinfold's value obtained in millimeters was converted to centimeters and then applied to the following equation: thigh perimeter (in centimeters) − (π × thigh skinfold [in centimeters]), as previous recommendation (Fernández Vieitez et al., 2001;Frisancho, 1981;Heymsfield et al., 1990). The same experienced evaluator, Level 3 International Society for the Advancement of Kinanthropometry conducted the assessments (Schemes). ...
... Skeletal muscle mass is precisely assessed by dissection of cadavers (i.e., unique direct method), magnetic resonance, and computed tomography (i.e., indirect methods). Thus, the muscle mass verified by DXA (lean mass), US (MT), and AN (perimeter corrected by skinfold) are considered only an indirect assessment/ estimative of muscle mass (Abe et al., 2015;Heymsfield et al., 1990;Thiebaud et al., 2019). Heymsfield et al. (1990) observed a strong, positive correlation, and agreement, between lean mass assessed by DXA and magnetic resonance (i.e., reference method to measure muscle mass). ...
Decreased muscle quality (MQ) may explain functional capacity impairments during aging. Thus, it is essential to verify the interaction between MQ and functional capacity in older adults. We investigated the relationship between MQ and functional capacity in older adults (n = 34; 66.3 ± 4.6 year). MQ was estimated by maximum strength of knee extensors normalized to thigh muscle mass. Maximum strength was assessed on an isokinetic dynamometer (peak torque), while dual-energy X-ray absorptiometry (DXA), ultrasonography, and anthropometry were used to determine thigh muscle mass. Functional capacity was verified by 30-s sit to stand and timed up and go tests. Significant correlations were found between MQ assessed by DXA with 30-s sit to stand (r = .35; p < .05) and timed up and go (r = −.47; p < .05), and MQ assessed by anthropometry with timed up and go (r = −.41; p < .05), but not between MQ assessed by ultrasonography with functional capacity (p > .05). No significant relationship between muscle mass with functional capacity was observed. Thus, MQ assessed by DXA and MQ assessed by anthropometry may partially explain functional capacity in older adults. Interestingly, muscle mass alone did not explain performance in functional tests in this population
... In KNHANES, dual-energy X-ray absorptiometry (Discovery-W; Hologic Inc., Waltham, MA, USA) was used to measure body composition. Appendicular skeletal muscle mass (ASM) was calculated as the sum of skeletal muscle mass for both arms and legs, based on the assumption that all fat-free and bone-free tissues are skeletal muscles [24]. The low muscle mass index was calculated as ASM divided by body weight (%) [25]. ...
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Background Adults with low muscle mass have a poor prognosis. Studies that examined the association between total protein intake and low muscle mass among adults are limited. Thus, we investigated the association between total protein intake and low muscle mass among Korean adults aged ≥19 years. Methods We included 15,995 adults (6528 male and 9467 female) aged ≥19 years from the Korea National Health and Nutrition Examination Surveys (2008–2011). We divided the participants into groups according to protein intake quartile: Q1, Q2, Q3 and Q4 groups. The odds ratios (ORs) and 95% confidence intervals (CIs) of low muscle mass according to protein intake were analysed via multivariable logistic regression analysis. Stratified analyses according to sex, age and comorbidities were also performed. Results Of the participants, 3.8% had weight-adjusted low muscle mass. The prevalence rates of low muscle mass were 1.5, 3.0, 3.9 and 7.2% in the Q4, Q3, Q2 and Q1 groups, respectively ( p < 0.001). Compared with the Q4 group, the Q1 group had the highest ORs for low muscle mass, followed by the Q2 and Q3 groups (Model 5; OR, 95% CI: 2.03, 1.36–3.02 for Q3; 2.44, 1.64–3.61 for Q2; and 4.32, 2.89–6.45 for Q4) after adjusting for confounding variables (p for trend < 0.001). The associations between protein intake and low muscle mass were stronger in younger individuals, men, individuals without hypertension, those with diabetes mellitus and those without dyslipidemia. Conclusions The prevalence of low muscle mass in Korean adults significantly increased with lower protein intake. Nutrition education for proper protein intake is also important for adults. Trial registration Retrospectively registered.
... Janssen et al. [9] detected sarcopenia in the elderly using the SMI, with a cutoff of 2 SD below control. We followed Janssen's approach, and successfully identified sarcopenia in SOB subjects using SMI (ASM-replaces skeletal muscle mass/TBWt = 21.71 ± 0.89%) as a method of quantifying skeletal mass [16] with a percent ratio (Table 1) greater than 2 SD below the CN values (30.14 ± 2.64%). Sarcopenia in the OB group was also detected (24.08 ± 2.48%) using the same method. ...
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Background/Goal Caloric restriction—the most prevalent obesity treatment—has a 97% failure rate when spread over 5–7 years. Sarcopenic obesity is thought to be the consequence of chronic dieting and the cause of weight management problems. This pilot study’s goal was to develop a screening questionnaire that detects sarcopenic obesity in young and middle-aged female adults. Subjects/Method A total of 23 women (ages 19–59) completed a sarcopenic obesity questionnaire and were assessed for total body weight (TBWt), percent fat mass, and percent fat-free mass (%FFM) using the Bod Pod (air plethsmography), and bioelectrical impedance analysis (BIA). Appendicular skeletal mass (ASM) was calculated using BIA. Resting energy expenditure was determined using indirect calorimetry, and the basal metabolic rate (BMR) was calculated using BIA. Results The screening questionnaire score was negatively correlated with BMR (r² = 0.885), %FFM (r² = 0.86), ASM (r² = 0.79) relative to TBWt and to ASM/BMI (r² = 0.58). The screening questionnaire had an acceptable sensitivity (83%) and specificity (87%) in detecting sarcopenia measured using ASM/BMI. Conclusion This pilot intimates that subjects who frequently dieted suffered from a disproportionally lower FFM and BMR relative to the TBWt. The questionnaire can help clinicians recognize the presence of sarcopenic obesity in patients.
... CT scan cross-section at the level of the third lumbar vertebra provides a reliable representation of the total body muscle mass and has therefore been widely adopted for the detection of sarcopaenia in patients with cancer and allows assessment without additional ionising radiation exposure given that CT scans as part of routine cancer diagnostic procedures is largely available. 44 45 The thresholds for identifying muscle range from −29 to +150 Hounsfield Units (HU), subcutaneous and intramuscular adipose tissue from −190 to −30 HU, visceral adipose tissue from −150 to −50 HU and bone from +152 to 1000 HU. [46][47][48] Skeletal muscle radiodensity (SMD) that represents muscle quality will be measured using the average radiation attenuation of the tissue in HU. A low SMD is defined by values below the threshold of 37.8 HU. ...
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Introduction Patients with metastatic non-small cell lung cancer (mNSCLC) suffer from numerous symptoms linked to disease and treatment which may further impair the patient’s overall condition. In addition to its benefits on quality of life and fatigue, physical exercise may improve treatment response, notably due to its known effects on the immune system. The ERICA study is designed to assess the feasibility of a supervised acute physical exercise therapy realised immediately prior immune-chemotherapy infusion in patients with mNSCLC. Secondary objectives will examine the effects of acute exercise combined with an unsupervised home-walking programme on clinical, physical, psychosocial and biological parameters. Methods and analysis ERICA is a prospective, monocentric, randomised controlled, open-label feasibility study conducted at the Centre Léon Bérard Comprehensive Cancer Center (France). Thirty patients newly diagnosed with mNSCLC will be randomised (2:1 ratio) to the ‘exercise’ or the ‘control’ group. At baseline and during the last treatment cycle, participants in both groups will receive Physical Activity recommendations, and two nutritional assessments. In the exercise group, participants will receive a 3-month programme consisting of a supervised acute physical exercise session prior to immune-chemotherapy infusion, and an unsupervised home-based walking programme with an activity tracker. The acute exercise consists of 35 min interval training at submaximal intensity scheduled to terminate 15 min prior to infusion. Clinical, physical, biological and psychosocial parameters will be assessed at baseline, 3 and 6 months after inclusion. Biological measures will include immune, inflammatory, metabolic, oxidative stress biomarkers and molecular profiling. Ethics and dissemination The study protocol was approved by the French ethics committee (Comité de protection des personnes Ile de France II, N°ID-RCB, 8 December 2020). The study is registered on (NCT number: NCT04676009 ) and is at the pre-results stage. All participants will sign an informed consent form. The findings will be disseminated in peer-reviewed journals and academic conferences.
... In that guideline, sarcopenia has been defined as the existence of both low muscle mass and low muscular strength or low physical performance 27 . In order to calculate muscle mass, first we computed lean mass of the legs and hands (named as Appendicular Skeletal Muscle or ASM) and then through dividing this to height squared (ASM/height 2 ), we obtained total muscle mass for each study participant 31 . ASM was evaluated via DEXA scanner (Discovery W S/N 84430). ...
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There is no previous study that investigated the association between dietary intake of total and individual branched-chain amino acids (BCAAs) and odds of sarcopenia. The present study aimed to examine the association between dietary intake of BCAAs and sarcopenia and its components among Iranian adults. The data for this cross-sectional study was collected in 2011 among 300 older people (150 men and 150 female) with aged ≥ 55 years. We used a Block-format 117-item food frequency questionnaire (FFQ) to evaluate usual dietary intakes. BCAAs intake was calculated by summing up the amount of valine, leucine and isoleucine intake from all food items in the FFQ. The European Sarcopenia Working Group (EWGSOP) definition was used to determine sarcopenia and its components. Mean age of study participants was 66.8 years and 51% were female. Average intake of BCAAs was 12.8 ± 5.1 g/day. Prevalence of sarcopenia and its components was not significantly different across tertile categories of total and individual BCAAs intake. We found no significant association between total BCAAs intake and odds of sarcopenia (OR for comparison of extreme tertiles 0.48, 95% CI 0.19–1.19, P-trend = 0.10) and its components (For muscle mass 0.83, 95% CI 0.39–1.77, P-trend = 0.63; for hand grip strength 0.81, 95% CI 0.37–1.75, P-trend: 0.59; for gait speed 1.22, 95% CI 0.58–2.57, P-trend = 0.56). After adjusting for potential confounders, this non-significant relationship did not alter. In addition, we did not find any significant association between individual BCAAs intake and odds of sarcopenia or its components. We found no significant association between dietary intakes of BCAAs and sarcopenia in crude model (OR 0.60; 95% CI 0.29–1.26). After controlling for several potential confounders, the result remained insignificant (OR 0.48; 95% CI 0.19–1.19). In this cross-sectional study, no significant association was observed between dietary intakes of total and individual BCAAs and odds of sarcopenia and its components.
Amino acids (AAs) and dietary inflammatory potential play essential roles in muscle health. We examined the associations of dietary inflammatory index (DII) of habitual diet with serum AA profile, and ascertained if the associations between DII and muscle outcomes were mediated by serum AAs using general linear models, in 2994 older Chinese community-dwelling men and women (mean age 72 years) in Hong Kong. Higher serum branched chain AAs (BCAAs), aromatic AAs and total glutathione (tGSH) were generally associated with better muscle status at baseline. A more pro-inflammatory diet, correlating with higher serum total homocysteine and cystathionine, was directly (90.2%) and indirectly (9.8%) through lower tGSH associated with 4-year decline in hand grip strength in men. Higher tGSH was associated with favorable 4-year changes in hand grip strength, gait speed and time needed for 5-time chair stands in men and 4-year change in muscle mass in women. Higher leucine and isoleucine were associated with decreased risk of sarcopenia in men; the associations were abolished after adjustment for BMI. In older men, perturbations in serum sulfur AAs metabolism may be biomarkers of DII related adverse muscle status, while the lower risk of sarcopenia with higher BCAAs may partly be due to preserved BMI.
Aim: To evaluate the body fat distribution in children with cerebral palsy (CP). Method: The present study focusses on a monocentric retrospective analysis of body fat distribution from children diagnosed with CP. The children participated in a rehabilitation program. Reference centiles were calculated based on data from the National Health and Nutrition Examination Survey (NHANES, 1999-2004). Z-scores for trunk-to-leg fat ratio (T2L) were calculated. Further, fat mass index (FMI) was evaluated based on percentiles that have already been published. Results: 237 males and 194 females with CP were considered (mean age: 11 years and 11 months (SD 3 years)). These were compared to 1059 males and 796 females from the NHANES (mean age: 14 years and 7 months (SD 3 years and 4 months)). The z-scores for trunk-to-leg fat ratio showed the following values: mean -0.47 (SD 1.50) for males, -0.49 (SD 1.11), for females, -0.48 (SD 1.34) for all. The z-scores for FMI showed the following values: mean -0.29 (SD 0.70) for males, -0.88 (SD 2.0) for females, -0.55 (SD 1.46) for all. Interpretation: The results showed rather a gynoid fat distribution and a lower FMI in children with CP than in the reference population (NHANES 1999-2004).
Objectives: To compare volumetric CT with DL-based fully automated segmentation and dual-energy X-ray absorptiometry (DXA) in the measurement of thigh tissue composition. Methods: This prospective study was performed from January 2019 to December 2020. The participants underwent DXA to determine the body composition of the whole body and thigh. CT was performed in the thigh region; the images were automatically segmented into three muscle groups and adipose tissue by custom-developed DL-based automated segmentation software. Subsequently, the program reported the tissue composition of the thigh. The correlation and agreement between variables measured by DXA and CT were assessed. Then, CT thigh tissue volume prediction equations based on DXA-derived thigh tissue mass were developed using a general linear model. Results: In total, 100 patients (mean age, 44.9 years; 60 women) were evaluated. There was a strong correlation between the CT and DXA measurements (R = 0.813~0.98, p < 0.001). There was no significant difference in total soft tissue mass between DXA and CT measurement (p = 0.183). However, DXA overestimated thigh lean (muscle) mass and underestimated thigh total fat mass (p < 0.001). The DXA-derived lean mass was an average of 10% higher than the CT-derived lean mass and 47% higher than the CT-derived lean muscle mass. The DXA-derived total fat mass was approximately 20% lower than the CT-derived total fat mass. The predicted CT tissue volume using DXA-derived data was highly correlated with actual CT-measured tissue volume in the validation group (R2 = 0.96~0.97, p < 0.001). Conclusions: Volumetric CT measurements with DL-based fully automated segmentation are a rapid and more accurate method for measuring thigh tissue composition. Key points: • There was a positive correlation between CT and DXA measurements in both the whole body and thigh. • DXA overestimated thigh lean mass by 10%, lean muscle mass by 47%, but underestimated total fat mass by 20% compared to the CT method. • The equations for predicting CT volume (cm3) were developed using DXA data (g), age, height (cm), and body weight (kg) and good model performance was proven in the validation study.
Obesity is a health problem known to increase the morbidity and mortality of individuals. Although widely used, body mass index is not considered a good parameter to assess harmful levels of body fat, since is not a good predictor of mortality. Several new methods have been proposed over the years, such as the waist-to-hip radio. Nevertheless, the predictive ability of this method is still inconclusive. This study presents two new evaluation methods (bioelectrical impedance and dual energy x-ray) and assesses the accuracy of both. We evaluated 30 obese patients. The measurements were taken in the morning after a minimum period of 4 h of fasting, with an interval of 10 min between assessments. There was an improvement in the evaluative capacity of BIA in relation to DXA, when compared to previous studies. This led to an equivalence in the evaluative capacity of both formats for assessing body composition.
Amputees suffer from metabolic diseases. Thus, for a healthy life, management through body composition (BC) tests is useful. We aimed to validate between the bioimpedance analysis (BIAInBody_S10) and dual-energy X-ray absorptiometry (DXALunar Prodigy) method for evaluating BC in amputees. 78 male (n=66) and female (n=12) unilateral amputees, with either trans femoral amputation (TFA) or trans tibial amputation (TTA), were recruited. Correlation, agreement, and differences between fat free mass (FFM) and percentage fat mass (PFM), computed with the two methods, were tested using methods such as Pearson’s and Spearman’s correlation, Lin's concordance correlation coefficient (CCC), Bland–Altman plot, bivariate linear regression, and %Diff=100*(BIA-DXA)/DXA. In all groups, the FFM_BIA value was significantly overestimated compared to FFM_DXA; by contrast, the PFM_BIA value was significantly underestimated with respect to PFM_DXA. Additionally, differences between the results from the two methods were significantly higher for TFA than for TTA. In addition, a lower agreement between the two methods was observed in the TFA compared to the TTA group based on the correlation estimated through Lin's CCC. Moreover, body composition assessment with BIA needs to be carefully interpreted in amputees with some length of residual limb, especially regarding the TFA group.
Iliac crest biopsies from 56 postmenopausal osteoporotic females with spontaneous compression fractures and decreased total body Ca were compared to similar tissue from 48 normal controls. Biopsies were analyzed for bone density, Na, Ca, Mg, P, Co3, and hydroxyproline (OH-P). From the results OH-P/matrix, % mineral, and the ion content of the mineral were calculated. osteoporotic subjects showed decreased bone density, % mineral in bone, and OH-P in the bone matrix. Within the mineral, CO3 and Ca/P were decreased, while Na and Mg were increased. Statistical analysis showed that matrix OH-P and % mineral varied independently, and therefore the patients were separated into 4 subgroups: Group Ia: decreased matrix OH-P with normal % mineral (n = 9), Group Ib: decreased matrix OH-P with decreased % mineral (n = 5), Group IIa: normal matrix OH-P with normal % mineral (n = 33), Group IIb: normal matrix OH-P with decreased % mineral (n = 9). Decreased % mineral was associated with decreased bone density and an increase in Na and Mg in the mineral, which suggests skeletal Ca deficiency. Decreased matrix OH-P was associated with decreased bone density and, in the low % mineral group, with decreased mineral CO3 and Ca/P, suggesting a mineral of decreased mean crystal size. When both abnormalities coexisted (Group Ib), the greatest reduction in total body Ca was seen. Patients with normal matrix and normal % mineral (Group IIa) still had decreased bone density. The results suggest that in a large, clinically homogeneous population of postmenopausal osteoporotic women, 4 subgroups can be identified by differences in chemical composition of iliac crest biopsies.
The techniques of prompt gamma neutron-activation analysis for the measurement of total-body nitrogen and whole-body counting for the measurement of total-body potassium were used to determine the mass of muscle and nonmuscle lean tissue and their protein content in 135 normal male and female subjects, 20-80 yr of age. Age-related changes in the size of the muscle and nonmuscle compartments and their protein content provide basic data for the investigation of protein metabolism in aging subjects and in individuals with various metabolic disorders, particularly wasting diseases such as cancer. Significant age-related changes in the size of various body compartments were noted. The loss of muscle mass and its protein content contrasts with the relative constancy of the nonmuscle lean tissue and suggests that skeletal muscle is particularly vulnerable to the aging process.