Estimación de la masa grasa por DXA y el modelo de cuatro compartimentos en púberes mexicanos de 9 a 14 a？os

the objective of this study was to validate the estimation of body fat (%bf) by dxa (dual-energy x-ray absorciomdpx-md) against the four compartment model (4c) of body composition in 32 mexican pubertal girls and boys (aged 9 - 14y; f=16). the mean of the difference between dxa and 4c model was -3.5 %bf (p=0.171). the limits of agreement (95% ± 2 sd) were +5% to -12%bf. the precision of estimated limits of y the confidence intervals were -1.9% to -5.1%bf (p=0.050). the concordance correlation coefficient was pc= 0.85. the test of accuracy for coincidence of slop intercepts between dxa and the 4c model showed no coincidence (p< 0.05). the precision by r2 explained 83% of the variance (see, 4.1 %). the individual accuracy assess by the total error was 5.6%. the group mean accuracy by two way analysis of variance of body fat did not show interaction between method (dxa-4c model) and separate analysis of gender and overweight. however, there was an effect of method (p=0.043) in the presence of overweight (p<0.001). in conclusion, the estimation of percent of body fat by dxa was not precise and accurate in a group of mexican children. however, results do not limit the utility of dxa for the measurements of body composition and its relation with health outcomes, especially in follow up studies.