Body fat estimated by equations based on anthropometric parameters correlates with bioelectrical impedance in patients undergoing bariatric surgery

Abstract

Introduction: predictive equations to estimate body fat based on simple anthropometric parameters are easy to use in the clinical practice. Objective: to evaluate the relationship between predictive equations based on anthropometric parameters and bioelectrical impedance to estimate body fat in individuals undergoing bariatric surgery. Methods: a prospective and longitudinal study carried out with individuals undergoing bariatric surgery. Body weight, body mass index, waist circumference and body fat percentage estimated by anthropometric parameters and by impedance were evaluated at three moments, one month before, two and six months after surgery. Data were analyzed by one-way ANOVA for repeated measures with Holm-Sidak's post hoc or Friedman test with Tukey's post hoc, and Pearson or Spearman correlations, according to data distribution. Significance level adopted 5%. Results: twenty-five subjects composed the final sample. All anthropometric parameters reduced significantly over time (p<0.001). Except for Lean et al equation before surgery, the body fat percentage estimated by other formulas showed a strong correlation with impedance in all moments, with the highest correlation strength observed in Gómez-Ambrosi et al. equation. Conclusion: in the present study, the equations used showed a good correlation with bioelectrical impedance, and the Gómez-Ambrosi et al. equation as a better option to the use of bioimpedance to assess changes in body fat percentage of patients undergoing bariatric surgery for the treatment of severe obesity.