Assessment of Body Composition in Morbid Obesity: a Comparative Study Between Body Impedance and Adiposity index Methods

Abstract

Introduction Obesity has become an epidemic public health problem. A reliable method to assess body composition and monitor the effectiveness of treatments for the morbid obesity is mandatory. However, there is still controversy as to which method to use for this purpose. Two Methods are validated in the literature, bioelectrical impedance analysis (BIA) and body adiposity index (BAI). The present study compared these methodologies. Materials & Methods We evaluated 167 patients undergoing bariatric surgery, women prevailed (82.59 %), averaging 44 years-old and mean BMI of 49.48 kg/m2. Weight, height and hip circumference were measured. Body fat (BF) was calculated by BIA and BAI. The following formulas were used: BIA: BF in kg=023.25+(0.09x resistance in ohms)+(1.00x weight in kg)-(0.08xheight in cm)+(0.13x age in years). BAI: BF% of the total weight 0 (hip circumference in centimeters/height in meters x height in meters)-18. Results The patients had an average of 53.35 % (± 5.37) of BF according to BIA, and BAI showed 50.51 % (± 13.59) of BF. There is no difference between the two Methods (p<0,05), even when stratified by BMI (BMI<45, 45<BMI<50, BMI>50). Essa diferença variou quando o IMC foi dividido em três faixas, abaixo de 45 kg/m2 a diferença foi de 3,1 %, entre 45,1 a 49,99 kg/m2 a diferença foi de 3,78 %, acima de 50 kg/m2 a diferença foi de 1,86%. Discussion The BAI is a simple method of implementation, low cost and effective, when compared to other Methods validated for morbidly obese patients. Conclusion BAI is an effective method to assess BF, comparable to BIA, and also proved to be effective in super obese patients.