The use of bioelectrical impedance analysis (BIA) to estimate body composition in the Diabetes Control and Complications Trial (DCCT)

Although weight gain often accompanies intensive treatment regimens designed to achieve near-normal glycemia in insulin-dependent diabetes mellitus (IDDM), body composition (BC) has not been well studied. Bioelectrical impedance analysis (BIA) is a safe, rapid, and non-invasive method of assessing BC but has not been utilized widely in IDDM. Data from 46 adults with IDDM were used to develop a regression model estimating fat-free body mass (FFM) from bioimpedance measurements obtained using a proximal electrode placement. Reference values of FFM were determined by dual x-ray absorptiometry (DXA). A model using the ratio of height squared to the minimum resistance of 4 limb-lead combinations (H2/R), total body weight, and a weight-gender interaction achieved a high level of accuracy (R2 = 0.982, residual standard deviation = 1.43 kg), while studies of 10 subjects before and after a light meal found no short-term effect of glycemia on measured BIA variables. BIA will therefore be used in combination with waist-to-hip ratios to study the composition and distribution of the increased weight associated with intensive therapy in the DCCT.