Body composition measurement in obese patients with and without type 2 diabetes: comparison of methods

4 ACERO, Faculty of Health and Social Care School of Life Sciences, The Robert Gordon University, Aberdeen, Scotland, UK Background. Previous studies have compared body composition (BC) assessment methods in obese patients, however there is lack of literature on the comparison of bedside BC methods in obese diabetic subjects, particularly with respect to regional body fat (BF) distribution. The aim of this study was: to estimate the differences in fat mass (FM) using bioelectrical impedance (BIA), skinfold thickness (SFT) and body mass index (BMI) in comparison to the reference method of deuterium oxide (D2O) dilution in obese patients with and without type 2 diabetes (DM); to relate the differences in percentage of fat mass (%FM) to the regional body fat (BF) distribution. Materials and methods. BC was estimated using anthropometry, D2O, BIA, SFT, and BMI was used to calculate fat content in 94 obese patients, of whom 53 participants had type 2 DM (obese DM). Results. BIA and SFT yielded 5.2% and 6.1% lower (p < 0.001) results of %FM, respectively, in obese without DM, and 3.9% (p = 0.01) and 2.8% (p = 0.037) lower results in obese DM group, accordingly, compared to D2O dilution, while %FM calculated using BMI was higher by 3.2% (p = 0.045) in obese DM group. The difference estimated by BIA was constant for all the obesity classes, whereas for SFT increased in parallel with body weight. Fat in legs, arms, trunk area and waist to hip ratio were all important determinants for the difference in %FM between D2O dilution and bedside methods. Conclusions. The BIA and SFT underestimated FM in obese with and without DM, while BMI overestimated FM in obese DM group in comparison to D2O. The differences in regional body fat distribution were significant predictor variables, influencing the accuracy of the %FM estimated in all the patient groups.