title: Comparison of 3D laser-based photonic scans and manual anthropometric measurements of body size and shape in a validation study of 123 young Swiss men.
abstract: BACKGROUND
  Manual anthropometric measurements are time-consuming and challenging to perform within acceptable intra- and inter-individual error margins in large studies. Three-dimensional (3D) laser body scanners provide a fast and precise alternative: within a few seconds the system produces a 3D image of the body topography and calculates some 150 standardised body size measurements.
  
  
  OBJECTIVE
  The aim was to enhance the small number of existing validation studies and compare scan and manual techniques based on five selected measurements. We assessed the agreement between two repeated measurements within the two methods, analysed the direct agreement between the two methods, and explored the differences between the techniques when used in regressions assessing the effect of health related determinants on body shape indices.
  
  
  METHODS
  We performed two repeated body scans on 123 volunteering young men using a Vitus Smart XXL body scanner. We manually measured height, waist, hip, buttock, and chest circumferences twice for each participant according to the WHO guidelines. The participants also filled in a basic questionnaire.
  
  
  RESULTS
  Mean differences between the two scan measurements were smaller than between the two manual measurements, and precision as well as intra-class correlation coefficients were higher. Both techniques were strongly correlated. When comparing means between both techniques we found significant differences: Height was systematically shorter by 2.1 cm, whereas waist, hip and bust circumference measurements were larger in the scans by 1.17-4.37 cm. In consequence, body shape indices also became larger and the prevalence of overweight was greater when calculated from the scans. Between 4.1% and 7.3% of the probands changed risk category from normal to overweight when classified based on the scans. However, when employing regression analyses the two measurement techniques resulted in very similar coefficients, confidence intervals, andp-values.
  
  
  CONCLUSIONS
  For performing a large number of measurements in a large group of probands in a short time, body scans generally showed good feasibility, reliability, and validity in comparison to manual measurements. The systematic differences between the methods may result from their technical nature (contact vs. non-contact).
authors.affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Nikola
authors.initials: N
authors.lastname: Koepke
authors.affiliation: Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors.forename: Marcel
authors.initials: M
authors.lastname: Zwahlen
authors.affiliation: Childhood Nutrition Research Centre, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Wells
authors.affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Nicole
authors.initials: N
authors.lastname: Bender
authors.affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.|Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Maciej
authors.initials: M
authors.lastname: Henneberg
authors.affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rühli
authors.affiliation: Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Kaspar
authors.initials: K
authors.lastname: Staub
keywords: Body mass index; Height; Photonic scanning; Stature; Validation; Waist circumference; Waist-to-height-ratio; Waist-to-hip-ratio