Development of Regression Equation for the Measurement of Visceral Fat Area using Bioimpedance Technique.

ABSTRACT

Visceral fat is a predictor of obesity, metabolic syndrome and type II diabetes. The presently available technique, Computed tomography (CT) causes radiation exposure and is expensive. Abdominal obesity is a well established risk factor for obesity. There tends to be a risk of development of type 2 diabetes in obese individuals with abdominal obesity and insulin resistance. Abdominal obesity includes both subcutaneous and intra abdominal (visceral) adipose tissue and is associated with an increased risk of coronary heart disease (CHD) morbidity. A positive correlation between visceral fat, insulin levels and homeostasis model assessment insulin resistance index (HOMA-IR) in both genders was verified (r = 0.522 in boys and r = 0.309 in girls). The study aims at developing a bioelectrical impedance based system for visceral fat area. The visceral fat area of 126 subjects (age 38 ± 9 years) was first measured using the commercial instrument InBody 720 (Biospace, Korea) and then using the body composition analyzer (BCA) Bhabha Atomic Research Centre (BARC, Mumbai). Tetrapolar bioelectric impedance analysis (BIA) using two frequencies (50 KHz and 6.25 KHz) was used to develop the regression equation as follows VFA = [-142 + 187* whr + 1.94* weight (Kg) + 0.135* Zbody 50 (μ) + 1.027* age (years) -0.97* height (cm) + 7.2* sex -1.40* Zbody 50/W (μ Kg-1)] cm2; Sex = 0 for women and 1 for men (with R-sq adj = 96.87 and S = 5.37). The equation thus developed using BCA (BARC, Mumbai), validated with 60 subjects shows that there exists a high degree of correlation (R-sq adj = 96.87) between the two techniques.