## 3 Results
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Variables**} & **Female** & **Male** & **Total** \\  & **(n = 35) (55\%)** & **(n = 29) (45\%)** & **(n = 64)** \\  & **Mean (SD)** & **Mean (SD)** & **Mean (SD)** \\ \hline Age (years) & 12.19 (2.09) & 12.26 (2.20) & 12.22 (2.13) \\ Height (cm) & 147.28 (12.73) & 147.63 (14.08) & 147.44 (13.25) \\ Body mass BIA (kg) & 40.34 (10.80) & 39.26 (12.37) & 39.85 (11.46) \\ Body mass DXA (kg) & 40.03 (10.75) & 39.18 (12.61) & 39.64 (11.55) \\ BMI (kg/m\({}^{2}\)) & 18.24 (2.68) & 17.53 (2.66) & 17.92 (2.67) \\ \hline Total body composition & & & \\ BMC BIA (kg) & 1.81 (0.44) & 1.89 (0.59) & 1.85 (0.51) \\ BMC DXA (kg) & 1.50 (0.51) & 1.56 (0.48) & 1.53 (0.49) \\ Fat-free mass BIA (kg) & 31.88 (7.20) & 34.23 (11.36) & 32.95 (9.31) \\ Fat-free mass DXA (kg) & 29.55 (6.54) & 33.09 (11.10) & 31.15 (9.00) \\ LSTM BLA (kg) & 30.06 (6.76) & 32.35 (10.77) & 31.10 (8.81) \\ LSTM DXA(kg) & 27.99 (6.12) & 31.59 (10.62) & 29.62 (8.58) \\ Fat mass BIA (kg) & **8.46 (4.90) \({}^{*}\)** & 5.03 (2.57) & 6.91 (4.34) \\ Fat mass DXA (kg) & **10.48 (5.63) \({}^{*}\)** & 6.08 (3.18) & 8.49 (5.15) \\ \%BF BIA & **19.86 (6.86) \({}^{*}\)** & 12.95 (5.64) & 16.73 (7.18) \\ \%BF DXA & **24.85 (7.80) \({}^{*}\)** & 15.47 (6.50) & 20.60 (8.59) \\ \hline BIA measurements & & & \\ Total body water (L) & 23.41 (5.27) & 25.15 (8.34) & 24.20 (6.84) \\ Intracellular body water (L) & 14.50 (3.27) & 15.69 (5.30) & 15.04 (4.31) \\ Extracellular body water (L) & 8.91 (2.02) & 9.46 (3.05) & 9.16 (2.53) \\ Total 50 kHz Impedance & 1463.96 (171.18) & 1375.94 (255.33) & 1424.08 (216.19) \\ Total 50 kHz Reactance & 127.28 (71.69) & 121.73 (18.12) & 122.31 (17.75) \\ Impedance Index 50 kHz & 15.22 (3.51) & 16.96 (6.18) & 16.01 (4.94) \\ Right-side 50 kHz Impedance & 744.88 (87.48) & 698.43 (130.77) & 723.83 (110.79) \\ Right-side 50 kHz Reactance & 63.75 (9.10) & 63.13 (9.28) & 63.47 (9.11) \\ Right-side Impedance Index 50 kHz & 29.92 (6.93) & 33.45 (12.23) & 31.52 (9.77) \\ \hline HIV Infection parameters & & & \\ TCD4 lymphocytes (cells/u) & 854.31 (375.72) & 872.48 (365.92) & 862.55 (368.48) \\ TCD4 lymphocytes (\%) & 32.08 (9.30) & 28.35 (8.00) & 30.39 (8.86) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Study subjects physical and biological characteristics. The six models were substantially correlated with the DXA BMC values (Rho: 0.90 to 0.96), and there was no difference between the DXA BMC and the BMC values as estimated by the models (\(p>0.5\)) (Table 5). Figure 1 shows the linearity of the DXA BMC and the values estimated with the models. A random residual distribution was found in all of the models (model 1: \(x^{2}\) = 1.66, \(p\) = 0.19815; model 2: \(x^{2}\) = 0.84, \(p\) = 0.43502; model 3A: \(x^{2}\) = 0.76, \(p\) = 0.46982; model 3B: \(x^{2}\) = 0.78, \(p\) = 0.46452; model 4A: \(x^{2}\) = 0.71, \(p\) = 0.49637; model 4B: \(x^{2}\) = 0.79, \(p\) = 0.45952) (Figure 2). The internal validation of all of the selected models through bootstrap sampling (n = 5000) resulted in the following R\({}^{2}\) values: Model 1--0.82; model 2--0.89; model 3A--0.90; model 3B--0.90; model 4A--0.91; model 4B--0.90. Additional models were built based on FFM, TBW, and ICBW estimates to investigate whether the adjustments in the different stages of the BIA estimates resulted in better parameters. These models did not provided values for Rho, as well SEE and others parameters, and they were superior to the previously described models (Rho: 0.95, SSE: 0.012).