Smartphone derived anthropometrics: Agreement between a commercially available smartphone application and its parent application intended for use at point-of-care

Abstract

Smartphone applications can now automate body composition and anthropometric measurements remotely, prompting applications intended for use at point-of-care to provide commercially available smartphone applications intended for personal use. However, the agreement between such anthropometrics remain unclear. A total of 123 apparently healthy participants (F: 69; M: 54; age: 28.1±11.3; BMI: 26.9±5.9) completed consecutive body composition scans using a 3D smartphone application intended for personal use (MeThreeSixty; MTS) and it stationary counterpart intended for use in practice (Mobile Fit Booth; MFB). Agreement between devices were evaluated using root mean square error (RMSE), Bland-Altman analyses, and linear regression for all measurements, and additional equivalence testing was conducted for all circumference and limb length comparisons. When evaluated against the MFB, MTS significantly overestimated all measurements other than waist circumference (p=0.670) using paired t-tests. RMSE was 2.5% for body fat percentage (BF%), 0.64-3.74cm for all body circumferences, 0.71-2.3kg for all lean mass estimates, and 126-659cm2 and 608-4672cm3 across all body surface area and body volume estimates, respectively. BF% was the only body composition estimate that did not demonstrate proportional bias (p=0.221). Circumferences of the chest, shoulder, biceps, forearm, and ankle all demonstrated proportional bias (all coefficients: p<0.050), but only chest, shoulder, and arm circumferences did not demonstrate equivalence. Arm surface area (p<0.001) and arm (p=0.002) and leg volumes (p=0.004) were the only body surface area and volume estimates to reveal proportional biases. These findings demonstrate the agreement between 3D anthropometric applications intended for clinical and personal use, particularly for whole-body composition estimates and clinically meaningful body circumferences. Given the advantages of commercially available remote applications, practitioners and consumers may consider using this method in place of those intended for clinical practice, but should express caution when overestimation is a concern.