We compared the whole body (WB) and segmental bioelectrical
impedance analysis (BIA) methodologies in a group of healthy
adults (
n = 25). It has been suggested that the segmental methodology
may overcome the difficulty in generating a single algorithm
to predict total body water (TBW) in all groups whether healthy
or not. We measured TBW, using D
2O dilution, and WB and segmental
BIA parameters. Cole-Cole analysis was used to determine the
impedance at the characteristic frequency (
Zc). The correlation
between TBW (by D
2O dilution) and segmental BIA measures (multiple
regression,
r = 0.90,
p < 0.001, SEE = 3.1 L) was not significantly
higher than the correlation between TBW (D
2O dilution) and WB
BIA measures (simple regression,
r = 0.85,
p < 0.001, SEE
= 3.6 L). Others have observed this "lack of improvement" in
a group of healthy subjects. The true value of the segmental
BIA methodology may lie in applications involving groups with
altered distributions of segmental and compartmental fluid.
