Bioelectrical impedance vector reference values for assessing body composition in a Spanish child and adolescent population

Objectives Reference values of the bioelectrical impedance vector for the Spanish child and adolescent population are needed for assessing body composition and hydration status in this population. The aim of this study is to provide reference values of the bioelectrical impedance vector in Spanish children and adolescents aged 4‐18 years from Castilla y León. Methods This was a cross‐sectional descriptive study conducted in 4401 Spanish healthy children and adolescents aged 4‐18 years (2265 boys and 2136 girls). Resistance and reactance were measured with a single‐frequency impedance analyzer at 50 kHz (tetrapolar analysis). The values of resistance and reactance normalized by height were used to plot the bivariate 50th, 75th, and 95th percentiles of the population by age group. Mean impedance vectors were compared with Hotelling's T2 test for vector analysis (differences being considered significant if p