Body fat percentage estimation in children - searching for the most accurate equation

Background and aims: Analysis of body composition is a very important issue, and it is often used as one of the crucial markers of overall health. The aim of the study was to analyse the relationship between the percentage of body fat ratio estimated using selected equations and adiposity obtained by bioimpedance in 7-16-year-olds from Kraków (Poland). Methods and results: The study included 1887 children and adolescents. Body weight and height were measured according to standard methods and Body Mass Index was calculated on the basis of those measurements. Biceps, triceps, subscapular, suprailiac, abdominal and calf skinfolds were measured. Adiposity was obtained using the BIA method as well as estimated by Siri, Goran, Slaughter, Deurenberg, Huang, Dezenberg, Ripka and Brożek equations. Relationship between results obtained from the equations and bioimpedance was assessed using Deming regression. All calculations were performed using Microsoft Excel and MedCalc. Statistically significant (p ≤ 0.001) relationship between adiposity obtained by bioimpedance and estimated was observed for all of the analysed equations. For girls, the strongest one was noted for Siri equation, with R = 0.83 (95%CI: 0.81-0.85). Among boys, the strongest relationship was observed for 3-skinfolds based equation developed by Ripka, with the Pearson's correlation coefficient value of 0.84 (95%CI: 0.81-0.85). Conclusions: The most useful equation to estimate the body fat percentage in the population of 7-16-year olds from Kraków (Poland) differed between the sexes. For boys, it was Ripka 3-skinfold equation, while for girls it was the equation developed by Siri.