Technical note: Criterion validity of whole body surface area equations: a comparison using 3D laser scanning.

Measurements of whole body surface area (WBSA) have important applications in numerous fields including biological anthropology, clinical medicine, biomechanics, and sports science. Currently, WBSA is most often estimated using predictive equations due to the complex and time consuming methods required for direct measurement. The main aim of this study was to identify whether there were significant and meaningful differences between WBSA measurements taken using a whole body three-dimensional (3D) scanner (criterion measure) and the estimates derived from each WBSA equation identified from a systematic review. The study also aimed to determine whether differences varied according to body mass index (BMI), sex, or athletic status. Fifteen WBSA equations were compared with direct measurements taken on 1,714 young adult subjects, aged 18-30 years, using the Vitus Smart 3D whole body scanner, including 1,452 subjects (753 males, 699 females) from the general Australian population and 262 rowers (148 males, 114 females). Mixed-design analysis of variances determined significant differences and accuracy was quantified using Bland-Altman analysis and effect sizes. Thirteen of the 15 equations overestimated WBSA. With a few exceptions, equations were accurate with a low-systematic error (bias ≤2%) and low-random error (standard deviation of the differences 1.5-3.0%). However, BMI did have a substantial impact with the accuracy of some WBSA equations varying between the four BMI categories. The Shuter and Aslani: Eur J Appl Physiol 82 (2000) 250-254 equation was identified as the most accurate equation and should be used for Western populations 18-30 years of age. Care must be taken when deciding which equation to use when estimating WBSA.