Validity of the output variables of body composition in healthy Guatemalan adults using the SECA mBCA 525 bioelectrical impedance analyzer
Authors: Arriaga Claudia Lorena , Tanchez Carlos , Diaz‐Jereda Liza Alejandra , Solomons Noel W. , Schümann Klaus 
Published: November 2023

BackgroundCommon measurements in health diagnosis are those related to body size: height and weight, which are used to obtain the body mass index. But height and weight are not enough to estimate values for muscle, fat and skeletal mass let alone give any information on the individual's hydration status, which are also significant indicatives of body health diagnosis. Bioelectrical impedance analysis (BIA) on the other hand is a technique that uses the properties of conductivity capacitance and restriction of electron flow, to measure both conductive (hydrated tissues) and non‐conductive (adipose tissues) components, modeling the responses for the quantification of total body water, fat and lean tissue. Guatemala's conjunct problems of short stature (stunting), emergent excess weight (overweight, obesity) and suspected hypohydration present challenges worthy of investigative address. Therefore, assessment of body composition with a new generation of BIA promises a useful public health applications.ObjectiveApply the SECA mBCA 525 BIA instrument when measuring 33 Guatemalan adults, to assess the within‐individual test‐retest reproducibility during various intervals of time.MethodsBasic data on age, sex, weight, height, waist‐circumference and habitual physical activity were combined with measurements using the BIA for intervals of 60 min (n=9, x5), 24 h (n=12, x2) and 7 days (n=12, x2) among male (n=14) and female (n=19) Guatemalan adults. The most relevant BIA related‐variables were: energy stored in body (kcal): fat mass (kg); fat mass (%); fat mass index (kg/m2); fat‐free mass (kg); fat‐free mass (%); fat‐free mass index (kg/m2); skeletal muscle mass (kg);visceral fat (kg); total body water (L); total body water (%); extracellular water (l); extracellular water (%); hydration (%); phase angle (degrees), a derivative of the bioimpedance vector. Coefficients of variation and Pearson and Lin correlations were used to assess reproducibility.ResultsAcross the 33 individuals, varying in BMI from 19.4–39 kg/m2, all test‐retest variables were stable in all time‐intervals. Measurements made for the 60‐min group (n=9, x5) showed a range of Pearson coefficients between 0.841–0.999 and Lin coefficients between 0.795–0.999. All variables had values for both Pearson and Lin coefficient above 0.985 except for fat free mass (0.841, 0.795) and fat free mass index (0.972, 0.992). For the 24‐h group (n=12, x2), Pearson coefficients between 0.925–0.993 and Lin coefficients between 0.910–0.992 were found. The lowest correlations for Pearson and Lin were displayed in visceral fat (0.942–0.916), hydration (0.926–0.916) and phase angle (0.925–0.910). As for the group measured in the time interval of 7 days (n=12, x2) the range of Pearson coefficients laid between (0.744–0.996) and the Lin coefficients between (0.739–0.994) the lowest correlations found in hydration (0.744–0.739) and the phase‐angle (0.935–0.909).ConclusionsThe SECA mBCA 525 provides plausible body composition values, with outstanding within‐subject reproducibility at all intervals of time measured.