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Practical Implications
- Tanita BIA measurements correlate highly with both the
DEXA and Underwater weighing methods. Tanita Body Composition
Analyzers provide accurate results without the discomfort,
expense, or expert training necessary for other methods
- In fact, Tanita BIA correlates with both DEXA and UWW better
than the two methods, normally considered the gold standards
for determining body fat percentage, correlate with each
other. The lower correlation between the "gold
standards" suggests that it is important to use the
same method consistently to determine patient fitness trends.
- Anthropometry (calipers) did not correlate well with any
of the reliable clinical methods of determining body fat.
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ABSTRACT
| Objective:
Monitoring composition of weight loss during dieting is
an important aspect of evaluating a patient's treatment program.
On conventional diets ~75% of weight loss consists of fat
(i.e. change in fat/change in body weight ~0.75.). Research
based methods such as underwater weighing (UWW) and dual
energy x-ray absorptiometry (DEXA) are useful in assessing
composition of weight loss, although not much information
is available on accuracy/comparability of clinical methods
including anthropometry (Anth) and bioimpedance analysis
(BIA). The aim of this study was to compare body composition
changes with weight loss between research based methods and
clinical methods.
Design:
16 week weight loss study of healthy obese subjects on prescribed
low calorie diet.
Correlation Data
(1 = perfect correlation)
| **p<0.001 |
Anth |
UWW |
DEXA |
BIA |
| Anth |
1.00 |
.657** |
.757** |
.745** |
| UWW |
.657** |
1.00 |
.822** |
.834** |
| DEXA |
.757** |
.822** |
1.00 |
.887* |
| BIA |
.745** |
.834** |
.887** |
1.00 |
|
Materials & Method:
Change in fat mass was assessed with UWW, DEXA {Lunar DPX],
Anth (Durnin-Womersley), and BIA (Tanita TBF-305).
Results:
There were 73 subjects with (X ±SD) age 42.6± 9.9
yrs & BMI=31.7±3.1 kg/m². Mean group weight
loss was 5.4 kg. A correlation matrix with r values for change
in fat mass is shown in the following table. Both clinical
methods were significantly correlated with UWW and DEXA,
with BIA r's > than Anth. The fraction of weight loss
as fast was established for each method of regression: .79
DEXA R²=.83; .77 BIA (.88); .77 UWW (.69) and .57 Anth
(.65)
BIA VS. ANTHROPOMETRY
(Taller is better)
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| |
| Conclusion: These
results suggest clinical methods, notably BIA, correlate with
and provide similar composition of weight loss results to research-based
body composition methods. |
*C. Nunez, J. Beyer*, G. Strain*, B. Zumoff**, A. Kovera, D. Gallagher & S.B.
Heymsfield
Obesity Research Center., St. Luke's\Roosevelt Hospital, Columbia University,
NY, NY 10025
*Mt. Sinai Hospital, NY, NY 10029, **Beth Israel Medical Center, NY, NY 10003
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