Improved prediction formula for total body water assessment in obese women.
OBJECTIVE
To validate an improved formula for the calculation of total body water (TBW) from impedance values in obese women.


METHODS
A sample of 37 overweight females BMI ranging from 29.5 to 44.1 kg/m2.


METHODS
The reference measurements for TBW were obtained by deuterium oxide dilution. Body height (h), hip circumference (C) as well as body impedance at 100 kHz (Z100) were also measured.


RESULTS
The values obtained for h, C and Z100 were introduced in the calculations and the following developed formula for total body water was determined: TBW = 0.069 [hC2/(4 pi .Z100)]+19.671. The validity of this formula was assessed through the statistical test of Bland and Altman which we also performed for other formulas containing the weight and/or the height.


CONCLUSIONS
We found that the accuracy of the prediction of TBW by our formula, although lower than those formulas using body weight, is higher than that which takes into account only body height. We conclude that body volume, expressed through body height and hip circumference, is a good choice of parameter in bioelectrical impedance measurements. The new approach can be useful in clinical settings for repeated monitoring of obese women, during diet-restricted treatment.
D000328:Adult; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D001827:Body Height / Q000502:physiology; D001834:Body Water / Q000378:metabolism*; D001835:Body Weight / Q000502:physiology; D017666:Deuterium Oxide; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012016:Reference Values
D017666:Deuterium Oxide