Can we use the Jackson and Pollock equations to predict body density/fat of obese individuals in the 21st century?

2.50
Hdl Handle:
http://hdl.handle.net/2436/39333
Title:
Can we use the Jackson and Pollock equations to predict body density/fat of obese individuals in the 21st century?
Authors:
Nevill, Alan M.; Metsios, Giorgos S.; Jackson, A.S.; Wang, J.; Thornton, J.; Gallagher, D.
Abstract:
Objective: Jackson and Pollock’s (JP) ground-breaking research reporting generalized body density equations to estimate body fat was carried out in the late 1970s. Since then we have experienced an ‘obesity epidemic’. Our aim was to examine whether the original quadratic equations established by Jackson and co-workers are valid in the 21st century. Methods: Reanalyzing the original JP data, an alternative, more biologically sound exponential powerfunction model for body density is proposed that declines monotonically, and hence predicts body fat to rise monotonically, with increasing skin-fold thicknesses. The model also remains positive irrespective of the subjects’ sum-of-skinfold thicknesses or age. Results: Compared to the original quadratic model proposed by JP, our alternative exponential power-function model is theoretically and empirically more accurate when predicting body fat of obese subjects (sums of skinfolds >120mm). A cross-validation study on 14 obese subjects confirmed these observations, when the JP quadratic equations under estimated body fat predicted using dual energy x-ray absorptiometry (DXA) by 2.1% whereas our exponential power-function model was found to underestimate body fat by less than 1.0%. Otherwise, the agreement between the DXA fat (%) and the two models were found to be almost identical, with both coefficients of variation being 10.2%. Conclusions: Caution should be exercised when predicting body fat using the JP quadratic equations for subjects with sums of skinfolds>120 mm. For these subjects, we recommend estimating body fat using the tables reported in the present manuscript, based on the more biologically sound and empirically valid exponential power-function model.
Citation:
International Journal of Body Composition Research, 6(3): 114–121
Publisher:
Smith-Gordon
Journal:
International Journal of Body Composition Research
Issue Date:
2008
URI:
http://hdl.handle.net/2436/39333
Additional Links:
http://www.ijbcr.com/; http://www.ijbcr.com/IJBCR_6.3.pdf
Type:
Article
Language:
en
Description:
The full text pdf appears with the kind permission of the publisher, Smith-Gordon.
ISSN:
1479-456X
Appears in Collections:
Sport, Exercise and Health Research Group; Exercise and Health; Learning and Teaching in Sport, Exercise and Performance

Full metadata record

DC FieldValue Language
dc.contributor.authorNevill, Alan M.-
dc.contributor.authorMetsios, Giorgos S.-
dc.contributor.authorJackson, A.S.-
dc.contributor.authorWang, J.-
dc.contributor.authorThornton, J.-
dc.contributor.authorGallagher, D.-
dc.date.accessioned2008-10-21T08:42:07Z-
dc.date.available2008-10-21T08:42:07Z-
dc.date.issued2008-
dc.identifier.citationInternational Journal of Body Composition Research, 6(3): 114–121en
dc.identifier.issn1479-456X-
dc.identifier.urihttp://hdl.handle.net/2436/39333-
dc.descriptionThe full text pdf appears with the kind permission of the publisher, Smith-Gordon.en
dc.description.abstractObjective: Jackson and Pollock’s (JP) ground-breaking research reporting generalized body density equations to estimate body fat was carried out in the late 1970s. Since then we have experienced an ‘obesity epidemic’. Our aim was to examine whether the original quadratic equations established by Jackson and co-workers are valid in the 21st century. Methods: Reanalyzing the original JP data, an alternative, more biologically sound exponential powerfunction model for body density is proposed that declines monotonically, and hence predicts body fat to rise monotonically, with increasing skin-fold thicknesses. The model also remains positive irrespective of the subjects’ sum-of-skinfold thicknesses or age. Results: Compared to the original quadratic model proposed by JP, our alternative exponential power-function model is theoretically and empirically more accurate when predicting body fat of obese subjects (sums of skinfolds >120mm). A cross-validation study on 14 obese subjects confirmed these observations, when the JP quadratic equations under estimated body fat predicted using dual energy x-ray absorptiometry (DXA) by 2.1% whereas our exponential power-function model was found to underestimate body fat by less than 1.0%. Otherwise, the agreement between the DXA fat (%) and the two models were found to be almost identical, with both coefficients of variation being 10.2%. Conclusions: Caution should be exercised when predicting body fat using the JP quadratic equations for subjects with sums of skinfolds>120 mm. For these subjects, we recommend estimating body fat using the tables reported in the present manuscript, based on the more biologically sound and empirically valid exponential power-function model.en
dc.language.isoenen
dc.publisherSmith-Gordonen
dc.relation.urlhttp://www.ijbcr.com/en
dc.relation.urlhttp://www.ijbcr.com/IJBCR_6.3.pdf-
dc.subjectBody densityen
dc.subjectMonotonic declineen
dc.subjectPercentage body faten
dc.subjectSkinfold thicknessen
dc.subjectBody Mass Indexen
dc.subjectBody compositionen
dc.subjectBMI-
dc.titleCan we use the Jackson and Pollock equations to predict body density/fat of obese individuals in the 21st century?en
dc.typeArticleen
dc.identifier.journalInternational Journal of Body Composition Researchen
All Items in WIRE are protected by copyright, with all rights reserved, unless otherwise indicated.