The utility of dual bioelectrical impedance analysis in detecting intra-abdominal fat area in obese patients during weight reduction therapy in comparison with waist circumference and abdominal CT

An increase in intra-abdominal fat area (IAFA) is an essential component of metabolic syndrome (MetS). Waist circumference (WC) is not a precise measure of IAFA, and computed tomography (CT) is unsuitable for frequent monitoring. Here, we examined utility of a dual bioelectrical impedance analysis (Dual BIA) for measuring IAFA in obese patients during weight reduction. Fat distribution was measured by Dual BIA and CT in 100 obese outpatients. All fat areas including total, IAFA, and subcutaneous fat by Dual BIA were more closely correlated with those by CT than WC. Estimated IAFA by Dual BIA was significantly correlated with number of MetS components as well as CT, but WC was not. Furthermore, in 61 obese patients who received 6-month weight reduction therapy, estimated IAFA by Dual BIA showed an earlier and greater decrease as well as that by CT than WC and BMI. In addition, decrease in estimated IAFA by Dual BIA through weight reduction had a higher correlation with decrease in IAFA by CT, than WC. This study is the first to demonstrate that the change in estimated IAFA by Dual BIA was highly correlated with that in IAFA by CT during weight reduction therapy. Our findings also indicate that estimated IAFA by Dual BIA is, potentially, a better indicator of severity of MetS, cardiovascular risk factors, and effectiveness of weight reduction than WC, and equal to IAFA by CT. Estimated IAFA by Dual BIA may be useful for monitoring the effectiveness of weight reduction therapy in obese patients.