UCSF

Background/objectives

Obesity is a significant worldwide epidemic that necessitates accessible tools for robust body composition analysis. We investigated whether widely available 3D body surface scanners can provide clinically relevant direct anthropometrics (circumferences, areas and volumes) and body composition estimates (regional fat/lean masses).

Subjects/methods

Thirty-nine healthy adults stratified by age, sex and body mass index (BMI) underwent whole-body 3D scans, dual energy X-ray absorptiometry (DXA), air displacement plethysmography and tape measurements. Linear regressions were performed to assess agreement between 3D measurements and criterion methods. Linear models were derived to predict DXA body composition from 3D scan measurements. Thirty-seven external fitness center users underwent 3D scans and bioelectrical impedance analysis for model validation.

Results

3D body scan measurements correlated strongly to criterion methods: waist circumference R²=0.95, hip circumference R²=0.92, surface area R²=0.97 and volume R²=0.99. However, systematic differences were observed for each measure due to discrepancies in landmark positioning. Predictive body composition equations showed strong agreement for whole body (fat mass R²=0.95, root mean square error (RMSE)=2.4 kg; fat-free mass R²=0.96, RMSE=2.2 kg) and arms, legs and trunk (R²=0.79-0.94, RMSE=0.5-1.7 kg). Visceral fat prediction showed moderate agreement (R²=0.75, RMSE=0.11 kg).

Conclusions

3D surface scanners offer precise and stable automated measurements of body shape and composition. Software updates may be needed to resolve measurement biases resulting from landmark positioning discrepancies. Further studies are justified to elucidate relationships between body shape, composition and metabolic health across sex, age, BMI and ethnicity groups, as well as in those with metabolic disorders.