BODPOD GS: Derivation of Body Fat Correction-Equation
Presentation
Overview
Overview
Description
Background: The value of information collected by an instrument and/or equipment is dependent upon its degree of validity. Practitioners, researchers, and clinicians should verify the accuracy of instruments and equipment prior to disseminating information to their clientele.
Purpose: To derive a body fat correction-equation that will provide results equivalent to the applied Gold Standard obtained from the BOD POD GS.
Methods: Two hundred females and 134 males (Age = 21.8±6.8 and 22.5±8.0 years; BMI 22.7±2.5 and 24.4±2.6 kg/m2, respectively), underwent percent body fat (%BF) assessments via four methods (BODPOD GS, Hand-Hand BIA, Foot-Foot BIA1, and Foot-Foot BIA2) in a randomized sequence to mitigate sequence bias. Pearson correlation determined interrelationships, paired sample t-tests assessed mean differences, linear regression facilitated equation derivation, and mean absolute differences (MAD) quantified average errors for individuals. Sex-specific analyses were conducted for all procedures.
Results: Mean BODPOD GS %BF values were 22.6±6.9 for females and 14.9±6.3 for males. Systematic underestimated values for Hand-Hand BIA, Foot-Foot BIA1, and Foot-Foot BIA2 were -3.0, -2.2, and -1.2 for females, and -2.1, -2.9, and -0.2 for males, with all mean %BF significantly different from BODPOD GS except for males using Foot-Foot BIA2 (14.7±5.0; p=0.68). Correlations ranged from 0.73 to 0.75 for females and 0.52 to 0.66 for males. Female correction-equations to estimate BODPOD %BF were a) -2.556 + (1.246*Hand-Hand BIA), b) 1.542 + (1.03*Foot-Foot BIA1), c) 4.156 + (0.878*Foot-Foot BIA2). Male correction-equations to estimate BODPOD %BF: a) 2.02 + (1.0*Hand-Hand BIA), b) 3.670 + (0.935*Foot-Foot BIA1), and c) 5.784 + (0.62*Foot-Foot BIA2). For females, MAD changed from 4.7% to 3.6% (Hand-Hand BIA), 4.0% to 3.5% (Foot-Foot BIA1), and 3.8% to 3.6% (Foot-Foot BIA2). For males, MAD changed from 4.1% to 3.8% (Hand-Hand BIA), 4.4% to 4.0% (Foot-Foot BIA1), and 4.4% to 4.2% (Foot-Foot BIA2) when compared to BODPOD GS.
Conclusions: The investigation revealed moderate to moderately high correlations and statistically significant mean differences. Despite these findings, the biases and mean absolute differences remained within the established margin of error for body fat percentage estimation. The formulated correction-equations achieved a reduction, albeit small, in MAD values.
