Poster Presentation The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2017

Body composition to estimate percentage fat mass: Comparisons between common clinical methods and gold-standard air displacement plethysmography (BODPOD) in a cohort of university students. (#223)

Lisa K Akison 1 , Linda A Gallo 1 2 , Johanna L Barclay 2 , Danielle Burgess 1 , Sahar Keshvari 2 , Amelia K Fotheringham 2 , Karen M Moritz 1 3
  1. School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
  2. Mater Research, The University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
  3. Child Health Research Centre, Centre for Children’s Health Research, The University of Queensland, South Brisbane, QLD, Australia

Obesity is defined as an excess in body fat and is associated with an increased risk of type-2 diabetes-mellitus, hypertension, dyslipidemia and heart failure. Australian statistics based on body mass index (BMI) indicate that 63% of adults are overweight/obese and this is predicted to rise. BMI is the most commonly used measure to define overweight/obesity, but does not distinguish between fat and lean mass and can over- or under-estimate BMI depending on height. The ‘gold standard’ for estimation of fat mass is air displacement plethysmography (BODPOD), but is expensive and not readily available. We compared common and practical measures of body composition to the BODPOD in a cohort of university students. We used waist circumference (WC) and WC-height ratio (WC:H) as measures of visceral fat, bio-electrical impedance analysis of % body fat (BIA), % body fat calculated from skin-fold thickness (SFT) and BMI. Participants were recruited from a third-year biomedical practical class from The University of Queensland (2016-2017), with data obtained from 281 students (n=155 for SFT). Analyses were conducted separately for males and females. There were significant positive correlations between all measures and BODPOD % body fat in both sexes (P<0.0001). The most strongly correlated to the BODPOD were SFT and BIA in females (r=0.846, r=0.769) and SFT and WC:H in males (r=0.730, r=0.659), with WC and BMI showing relatively weaker associations, particularly in males (r=0.518, r=512). However, SFT had a tendency to over-estimate % body fat at low levels and underestimate at high levels, as shown by Bland-Altman plots, particularly in females. Therefore, we conclude that SFT and BIA correlate well with laboratory estimates of % fat mass but vary in their accuracy depending on degree of body fat and sex. BMI, although widely used, was the least predictive of body fat measured by the gold standard method.