Five-component model validation of reference, laboratory and field methods of body composition assessment

This study reports the validity of body fat percentage (BF%) estimates from several commonly employed techniques as compared with a five-component (5C) model criterion. Healthy adults (n 170) were assessed by dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), multiple bioimpedance techniques and optical scanning. Output was also used to produce a criterion 5C model, multiple variants of three- and four-component models (3C; 4C) and anthropometry-based BF% estimates. Linear regression, Bland-Altman analysis and equivalence testing were performed alongside evaluation of the constant error (CE), total error (TE), se of the estimate (SEE) and coefficient of determination (R (2)). The major findings were (1) differences between 5C, 4C and 3C models utilising the same body volume (BV) and total body water (TBW) estimates are negligible (CE <= 0 center dot 2 %; SEE < 0 center dot 5 %; TE <= 0 center dot 5 %; R (2) 1 center dot 00; 95 % limits of agreement (LOA) <= 0 center dot 9 %); (2) moderate errors from alternate TBW or BV estimates in multi-component models were observed (CE <= 1 center dot 3 %; SEE <= 2 center dot 1 %; TE <= 2 center dot 2 %; R (2) >= 0 center dot 95; 95 % LOA <= 4 center dot 2 %); (3) small differences between alternate DXA (i.e. tissue v. region) and ADP (i.e. Siri v. Brozek equations) estimates were observed, and both techniques generally performed well (CE < 3 center dot 0 %; SEE <= 2 center dot 3 %; TE <= 3 center dot 6 %; R (2) >= 0 center dot 88; 95 % LOA <= 4 center dot 8 %); (4) bioimpedance technologies performed well but exhibited larger individual-level errors (CE < 1 center dot 0 %; SEE <= 3 center dot 1 %; TE <= 3 center dot 3 %; R (2) >= 0 center dot 94; 95 % LOA <= 6 center dot 2 %) and (5) anthropometric equations generally performed poorly (CE 0 center dot 6- 5 center dot 7 %; SEE <= 5 center dot 1 %; TE <= 7 center dot 4 %; R (2) >= 0 center dot 67; 95 % LOA <= 10 center dot 6 %). Collectively, the data presented in this manuscript can aid researchers and clinicians in selecting an appropriate body composition assessment method and understanding the associated errors when compared with a reference multi-component model.

Automated summary

The study showed that differences between 5C, 4C and 3C models utilizing the same body volume and total body water estimates are negligible; moderate errors were observed from alternate total body water or body volume estimates in multi-component models; bioimpedance technologies performed well but exhibited larger individual-level errors; while anthropometric equations generally performed poorly.