Recent advancements in three-dimensional optical (3DO) imaging have made this technology readily available in fitness centers across the world. Advanced statistical methods have also been used to convert anthropometry and body shape into accurate and precise measures of regional and total body composition. However, it is unknown how well one can track body composition changes using 3DO. In this study, we investigate the accuracy of changes in body composition estimated by 3DO compared to the criterion DXA measures.
Ten percent of the Shape Up! Adults Study subjects participated in longitudinal protocols (diet or bariatric surgery) meant to alter their body composition. Each subject had a baseline and follow-up visit at the end of their intervention and included a DXA scan and 3DO surface imaging. 3DO scans were spatially registered using a standardized 60,000 vertex template. Body shape variation was described using principal component analysis. Stepwise regression was performed to create equations to predict fat mass (FM), fat-free mass (FFM), percent body fat (PBF), and visceral adipose tissue (VAT). Changes in these variables were calculated between follow-up and baseline measurements. 3DO body composition measurements were compared against DXA as the criterion method
Complete data from eight subjects (three female) were available at the time of this analysis. 11 PCA modes captured 95% of the body shape variance. 3DO changes in the variables were highly correlated to changes in DXA as follows: FM (R2 = 0.92, 0.58, and RMSE = 2.07kg), FFM (R2 = 0.58, RMSE = 4.12kg), PBF (R2 =0.47, RMSE = 4.02%), and VAT (R2 = 0.69, RMSE = 0.07kg).
Changes in 3DO PCs well represented changes in DXA body composition. 3DO scans are non-invasive, quick, and accessible technology that can be used often to improve the precision of its estimates while DXA cannot due to dose. This novel approach may have a high value for individuals undergoing lifestyle interventions and improve adherence