Author(s): Guerra RS, Amaral TF, Marques E, Mota J, Restivo MT
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Abstract OBJECTIVE: To identify which equation, Siri or Brozek, based on the two compartment model, provides a more accurate conversion of body density (BD) in percent body fat (\%BF) in a group of older adults. STUDY DESIGN: Cross-sectional study. SETTING: Research Centre in Physical Activity, Health and Leisure, Faculty of Sport, University of Porto. PARTICIPANTS: 60 older adults, aged 60-92 years. MEASUREMENTS: Skinfold thickness was used to estimate BD through Visser et al. prediction equation. The conversion of BD to \%BF was done with Siri (\%BF-Siri) and Brozek (\%BF-Brozek) formulas and these determined values were both compared to Dual-Energy X-ray Absorptiometry (\%BF-DXA) evaluations. RESULTS: A strong correlation between the \%BF-DXA value and \%BF-Siri (r=0.91, p < 0.001) and \%BF-Brozek (r=0.91, p < 0.001) was found, although \%BF-Siri and \%BF-Brozek overestimated \%BF-DXA (p < 0.001). The comparison of the \%BF-Siri and \%BF-Brozek mean values also revealed significant differences (p < 0.001). The \%BF-Brozek reflects a better agreement than the \%BF-Siri with \%BF-DXA with respectively a mean difference of -4.0 \%BF (limits of agreement = -10.9 to 2.9\%) and -5.7 \%BF (-12.6 to 1.2). The Bland and Altman plots confirmed that \%BF-Brozek reflects a better agreement with \%BF-DXA. CONCLUSION: The results of the present study show that the use of Brozek equation may correspond to a more accurate alternative than Siri equation for the conversion of BD in \%BF in older adults.
This article was published in J Nutr Health Aging
and referenced in Journal of Obesity & Weight Loss Therapy