Comparing digital anthropometrics from mobile applications to reference methods: a scoping review

This scoping review aimed to assess the repeatability and accuracy of Digital Anthropometry by Mobile Application (DAM) compared to reference methods for estimating anthropometric dimensions, body volume (BV), and body composition. A comprehensive search was conducted on December 8th, 2024, without restrictions on language, time, sex, ethnicity, age, or health condition. We found 14 different DAMs across the 23 included studies. Reference methods for each estimated variable were: (a) Body circumferences-tape measure; (b) body mass-calibrated scale; (c) body length-stadiometer; (d) BV-Underwater Weighing; (e) percentage of body fat-Dual energy x-ray absorptiometry (DXA), BOD POD, 3, 4, and 5-compartment models; (f) fat mass and fat-free mass-DXA, 3 and 4-compartment models; (g) appendicular Lean Mass-DXA. DAMs demonstrated high repeatability and accuracy at a mean level in most studies. However, their accuracy is lower at individual-level analysis and for tracking changes over time. Estimated BV showed high accuracy compared to UWW (SEE = 0.68; MD = 0.04 to 0.1; LoA = 2.86), including the BV-derived DAMs integrated into alternative multi-compartment models compared to reference methods. As relatively new methods, DAMs offer numerous possibilities and areas for exploration in future studies. However, caution is advised due to their potentially low or unknown accuracy at the individual level.