Body composition estimation from mobile phone three-dimensional imaging: evaluation of the USA army one-site method

• Published in: British journal of nutrition 2024-10, Vol.132 (9), p.1143-1151
• Main Authors: Florez, Christine M., Rodriguez, Christian, Siedler, Madelin R., Tinoco, Ethan, Tinsley, Grant M.
• Format: Article
• Language: English
• Subjects: Abdomen; Anthropometry; Armed forces; Army; Bias; Body composition; Body fat; Body mass index; Body measurements; Cameras; Cell phones; Cellular telephones; Dual energy X-ray absorptiometry; Estimates; Fat-free body mass; Health risk assessment; Health risks; Human and Clinical Nutrition; Laboratories; Military health care; Military personnel; Military preparedness; Obesity; Overweight; Performance evaluation; Physical fitness; Smartphones; Three dimensional imaging
• ISSN: 0007-1145; 1475-2662; 1475-2662
• DOI: 10.1017/S0007114524002216

Within the USA military, monitoring body composition is an essential component of predicting physical performance and establishing soldier readiness. The purpose of this study was to explore mobile phone three-dimensional optical imaging (3DO), a user-friendly technology capable of rapidly obtaining reliable anthropometric measurements and to determine the validity of the new Army one-site body fat equations using 3DO-derived abdominal circumference. Ninety-six participants (51 F, 45 M; age: 23·7 ± 6·5 years; BMI: 24·7 ± 4·1 kg/m2) were assessed using 3DO, dual-energy X-ray absorptiometry (DXA) and a 4-compartment model (4C). The validity of the Army equations using 3DO abdominal circumference was compared with 4C and DXA estimates. Compared with the 4C model, the Army equation overestimated BF% and fat mass (FM) by 1·3 ± 4·8 % and 0·9 ± 3·4 kg, respectively, while fat-free mass (FFM) was underestimated by 0·9 ± 3·4 kg (P < 0·01 for each). Values from DXA and Army equation were similar for BF%, FM and FFM (constant errors between −0·1 and 0·1 units; P ≥ 0·82 for each). In both comparisons, notable proportional bias was observed with slope coefficients of −0·08 to −0·43. Additionally, limits of agreement were 9·5–10·2 % for BF% and 6·8–7·8 kg for FM and FFM. Overall, while group-level performance of the one-site Army equation was acceptable, it exhibited notable proportional bias when compared with laboratory criterion methods and wide limits of agreement, indicating potential concerns when applied to individuals. 3DO may provide opportunities for the development of more advanced, automated digital anthropometric body fat estimation in military settings.