External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods.
<h4>Background</h4>Analysis of body composition is becoming increasingly important for the assessment, understanding and monitoring of multiple health issues. The body mass index (BMI) has been questioned as a tool to estimate whole-body fat percentage (FM%). Recently, a simple equation...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2019-01-01
|
| Series: | PLoS ONE |
| Online Access: | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0226767&type=printable |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850043341069090816 |
|---|---|
| author | Alan E Guzmán-León Ana G Velarde Milca Vidal-Salas Lucía G Urquijo-Ruiz Luz A Caraveo-Gutiérrez Mauro E Valencia |
| author_facet | Alan E Guzmán-León Ana G Velarde Milca Vidal-Salas Lucía G Urquijo-Ruiz Luz A Caraveo-Gutiérrez Mauro E Valencia |
| author_sort | Alan E Guzmán-León |
| collection | DOAJ |
| description | <h4>Background</h4>Analysis of body composition is becoming increasingly important for the assessment, understanding and monitoring of multiple health issues. The body mass index (BMI) has been questioned as a tool to estimate whole-body fat percentage (FM%). Recently, a simple equation described as relative fat mass (RFM) was proposed by Woolcott & Bergman. This equation estimates FM% using two anthropometric measurements: height and waist circumference (WC). The authors state that due to its simplicity and better performance than BMI, RFM could be used in daily clinical practice as a tool for the evaluation of body composition. The aim of this study was to externally validate the equation of Woolcott & Bergman to estimate FM% among adults from north-west Mexico compared with Dual-energy X-ray absorptiometry (DXA) as an alternative to BMI and secondly, to make the same comparison using air displacement plethysmography (ADP), Bioelectrical Impedance Analysis (BIA) and a 4-compartment model (4C model).<h4>Methods</h4>Weight, height and WC were measured following standard procedures. The RFM index was calculated for each of the 61 participating subjects (29 females and 32 males, ages 20-37 years). The RFM was then regressed against each of the four body composition methods for estimating FM%.<h4>Results</h4>Compared with BMI, RFM was a better predictor of FM% determined by each of the body composition methods. In terms of precision the best equation was RFM regressed against DXA (y = 1.12 + 0.99 x; R2 = 0.84 p<0.001). Accuracy (represented by the closeness to the zero-intercept) was 1.12 (95% CI: -2.44, to 4.68) and thus, not significantly different from zero. For the rest of the methods, precision in the prediction of FM% was improved compared to BMI, with significant increases in the R2 and reduction of the root mean squared error (RMSE). However, the intercepts of each regression did not show accuracy since they were different from zero, for ADP: -9.95 (95%CI: -15.7 to -4.14), for BIA: -12.6 (95%CI: -17.5 to -7.74) and for the 4C model: -13.6 (95%CI: -18.6 to -8.60). Irrespectively, FM% measured by each of the body composition methods was higher for DXA than the other three methods (p<0.001).<h4>Conclusions</h4>This external validation proved that the performance of the RFM equation used in this study to estimate FM% was more consistent than BMI in this Mexican population, showing a stronger correlation with DXA than with the other body composition methods. |
| format | Article |
| id | doaj-art-eeeb5bd9cb2e478098c7bf8d6b979489 |
| institution | DOAJ |
| issn | 1932-6203 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj-art-eeeb5bd9cb2e478098c7bf8d6b9794892025-08-20T02:55:16ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-011412e022676710.1371/journal.pone.0226767External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods.Alan E Guzmán-LeónAna G VelardeMilca Vidal-SalasLucía G Urquijo-RuizLuz A Caraveo-GutiérrezMauro E Valencia<h4>Background</h4>Analysis of body composition is becoming increasingly important for the assessment, understanding and monitoring of multiple health issues. The body mass index (BMI) has been questioned as a tool to estimate whole-body fat percentage (FM%). Recently, a simple equation described as relative fat mass (RFM) was proposed by Woolcott & Bergman. This equation estimates FM% using two anthropometric measurements: height and waist circumference (WC). The authors state that due to its simplicity and better performance than BMI, RFM could be used in daily clinical practice as a tool for the evaluation of body composition. The aim of this study was to externally validate the equation of Woolcott & Bergman to estimate FM% among adults from north-west Mexico compared with Dual-energy X-ray absorptiometry (DXA) as an alternative to BMI and secondly, to make the same comparison using air displacement plethysmography (ADP), Bioelectrical Impedance Analysis (BIA) and a 4-compartment model (4C model).<h4>Methods</h4>Weight, height and WC were measured following standard procedures. The RFM index was calculated for each of the 61 participating subjects (29 females and 32 males, ages 20-37 years). The RFM was then regressed against each of the four body composition methods for estimating FM%.<h4>Results</h4>Compared with BMI, RFM was a better predictor of FM% determined by each of the body composition methods. In terms of precision the best equation was RFM regressed against DXA (y = 1.12 + 0.99 x; R2 = 0.84 p<0.001). Accuracy (represented by the closeness to the zero-intercept) was 1.12 (95% CI: -2.44, to 4.68) and thus, not significantly different from zero. For the rest of the methods, precision in the prediction of FM% was improved compared to BMI, with significant increases in the R2 and reduction of the root mean squared error (RMSE). However, the intercepts of each regression did not show accuracy since they were different from zero, for ADP: -9.95 (95%CI: -15.7 to -4.14), for BIA: -12.6 (95%CI: -17.5 to -7.74) and for the 4C model: -13.6 (95%CI: -18.6 to -8.60). Irrespectively, FM% measured by each of the body composition methods was higher for DXA than the other three methods (p<0.001).<h4>Conclusions</h4>This external validation proved that the performance of the RFM equation used in this study to estimate FM% was more consistent than BMI in this Mexican population, showing a stronger correlation with DXA than with the other body composition methods.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0226767&type=printable |
| spellingShingle | Alan E Guzmán-León Ana G Velarde Milca Vidal-Salas Lucía G Urquijo-Ruiz Luz A Caraveo-Gutiérrez Mauro E Valencia External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. PLoS ONE |
| title | External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. |
| title_full | External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. |
| title_fullStr | External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. |
| title_full_unstemmed | External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. |
| title_short | External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods. |
| title_sort | external validation of the relative fat mass rfm index in adults from north west mexico using different reference methods |
| url | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0226767&type=printable |
| work_keys_str_mv | AT alaneguzmanleon externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods AT anagvelarde externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods AT milcavidalsalas externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods AT luciagurquijoruiz externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods AT luzacaraveogutierrez externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods AT mauroevalencia externalvalidationoftherelativefatmassrfmindexinadultsfromnorthwestmexicousingdifferentreferencemethods |