Development and validation of a novel waist girth-based equation to estimate fat mass in young Colombian elite athletes (F20CA Equation): A STROSA-Based Study
Date
2022-09-29
Authors
Bonilla Ocampo, Diego Alexander
Duque Zuluaga, Leidy Tatiana
Muñoz Urrego, Laura
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Abstract
The estimation of body fat percentage (%BF) from anthropometry-related data requires
population-specific equations to avoid incorrect interpretations in young athletes. Waist girth (WG)
has been described as potential predictor of fat mass (FM) in several populations; however, there
are no valid WG-based equations to estimate body composition in young Colombian athletes. The
aim of this STandardisierte BerichtsROutine für Sekundärdaten Analysen STROSA-based study was
twofold: i) to validate the relative fat mass (RFM) and its pediatric version (RFMp) compared to
dual-energy x-ray absorptiometry (DXA) and ii) to develop a new equation (F20CA) to estimate
the fat mass in Colombian children and adolescent elite athletes. A total of 114 young athletes
that belong to the ‘Team Medellín’ program (58F, 56M; 51 children, 63 adolescents; 14.85 [2.38]
years; 55.09 [12.16] kg; 162.38 [11.53] cm) participated in this cross-sectional study. The statistical
analysis revealed a poor correlation, agreement and concordance of RFMp and RFM estimations
with DXA measurements. After model specification using both Ordinary Least Square method and
Bayesian analysis, the regression output revealed that sex, body mass-to-waist ratio, and waistto-stature ratio were the statistically significant predictor variables that account for variability in
FM. The new F20CA equation is expressed as FM (kg) = 5.46 ∗ (Sex) + 0.21 ∗ (BM/W [kg/m]) +
81.7 ∗ (W/Stature [cm/cm]) − 41.8 (R2 = 0.683; SEE = 2.468 kg), where sex is 0 for males and 1 for
females. A moderate-to-high correlation and agreement of the F20CA was confirmed within the
internal validation data set (R
2 = 0.689; ICC [95%CI] = 0.805 [0.615, 0.904]; RMSE = 2.613 kg). The
Bland–Altman analysis corroborated the high concordance between the reference method (DXA) and
the F20CA-estimated FM (bias [95% LoA] = 1.02 [−3.77, 5.81] kg), indicating the two methods could
be considered interchangeable. Even though external validation is needed, practitioners are advised
to use the F20CA in young Colombian athletes with similar characteristics to those who participated
in this study.
Description
Keywords
Waist circumference, Body composition, DXA scan, Kinanthropometry, Regression equations, Bayesian analysis, Youth sports, Athletic performance