Comparison between dual-energy X-ray absorptiometry and skinfolds thickness in assessing body fat in anorexia nervosa before and after weight restoration

Summary Background & aims The aim of the study was to evaluate the correspondence between body fat mass composition (percentage) measured with dual-energy X-ray absorptiometry (DXA) and estimated by means of skinfold thicknesses (ST) measurement in patients with anorexia nervosa (AN), before and after weight gain. Methods Percentage body fat (%BF) was measured with DXA and estimated by ST measurements using Siri, Brozek, and Heyward equations in 27 adult patients with AN before and after weight gain (pre- and post-treatment) achieved with inpatient treatment and in 42 healthy age-matched controls. Results Due to Lohman criteria and Bland Altman plot there is no correspondence between the %BF measured with DXA and the %BF estimated by predictive equations based on ST measurements in patients with AN before and after weight gain, with the exception of Brozek equation which showed a mild agreement in pre-treatment AN. However, a correspondence was observed between the two procedures in healthy controls. Conclusions Our data supporting the use of ST measurements do not appear to be an alternative to DXA in estimating body fat percentage, before and after weight gain in patients with AN.