RESUMEN
Background: Validated equations to measure body composition in Chilean preschool children are lacking, since the only international equation available was developed in obese, and undernourished Caucasian children. Due to the increase in overweight and obesity in Chile, it is essential to have simple and reliable instruments to assess children. Aim: To design and validate anthropometric equations to estimate body fat (BF) and total body water (TBW) to be applicable in children aged 3 to 5 years, using deuterated water dilution as a reference method. Materials and Methods: Weight, height, circumferences and skinfold thickness were evaluated in 238 children aged 3 to 5 years, attending Junta Nacional de Jardines Infantiles (JUNJI). Several equations were developed using multiple regression models to estimate body water and fat. The proposed equations were validated against a sample of 77 children previously evaluated, using Bland and Alunan agreement analysis, that compares average differences of both methods with the average of predicted and estimated values. Results: New equations for TBW and BF were obtained, accounting for 86 percent and 72 percent in estimated variability. The agreement analysis showed a mean difference 0.001 ± 0.32 and 0.07 ± 0.56 kg, for TBW and BF, respectively, confirming the validity of the equations. Conclusions: The new validated equations in Chilean children aged 3 to 5 years, have an adequate and predictive capacity, especially useful for evaluating TBW and BF change in cohorts.