Validation of bioimpedance spectroscopy to assess acute changes in hydration status

Persistent Link:
http://hdl.handle.net/10150/280612
Title:
Validation of bioimpedance spectroscopy to assess acute changes in hydration status
Author:
Higgins, Karen J.
Issue Date:
2004
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
In this study bioimpedance spectroscopy (BIS) was validated as a field method for measuring short-term, small changes in hydration status by comparing extracellular water change (ΔECW) estimated by BIS with a criterion method (bromide dilution), dual energy X-ray absorptiometry (DXA) and body weight (BW). A secondary aim was to compare BW to bromide dilution as a method for estimating acute ΔECW. Finally, BIS was compared to DXA and single frequency bioimpedance analysis (SF-BIA) instruments to assess acute hydration effects on body composition estimates. During dehydration, no significant differences were found between bromide and BIS measures of ΔECW. The ΔECW measured by DXA (DXA-ΔECW) and BW (BW-ΔECW) was significantly different from bromide-estimated ΔECW (Br-ΔECW), but not from BIS estimates (BIS-ΔECW). During rehydration, there were no significant differences between Br-ΔECW and the other methods. When using BW as the reference, results were more consistent in that BW-ΔECW was significantly correlated with both BIS-ΔECW and DXA-ΔECW regardless of hydration status. These findings suggest that bromide may not be an appropriate criterion method for estimating short-term changes in hydration status. Regardless of hydration status, BIS provided accurate measures of fat-free mass (BIS-FFM) and fat mass (BIS-FM) that were comparable to, or better than, estimates by SF-BIA. At baseline and after dehydration BIS-FFM had the highest correlation with DXA estimates (DXA-FFM), although two SF-BIA instruments (Bio-Resistance Body Composition Analyzer from Valhalla Scientific and The Body Comp Scale from American Weights & Measures) produced good estimates of FFM. Rehydration appeared to affect the accuracy of FFM measurements by BIS and SF-BIA as evidenced by lower, more moderate correlations to DXA-FFM. Phase-dependent effects on percentage body fat (%BF) estimates were also apparent. In contrast, all methods performed reasonably well for estimates of FM, regardless of hydration status. In summary, BIS provides accurate estimates of ΔECW compared to either bromide dilution or BW, especially in the direction of dehydration. BIS also provides accurate estimates of FFM and FM regardless of hydration status. Further study of bromide dilution as a criterion measure is needed to validate its use in measuring ΔECW during acute shifts in hydration.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Health Sciences, Nutrition.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Nutritional Sciences
Degree Grantor:
University of Arizona
Advisor:
Howell, Wanda H.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleValidation of bioimpedance spectroscopy to assess acute changes in hydration statusen_US
dc.creatorHiggins, Karen J.en_US
dc.contributor.authorHiggins, Karen J.en_US
dc.date.issued2004en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIn this study bioimpedance spectroscopy (BIS) was validated as a field method for measuring short-term, small changes in hydration status by comparing extracellular water change (ΔECW) estimated by BIS with a criterion method (bromide dilution), dual energy X-ray absorptiometry (DXA) and body weight (BW). A secondary aim was to compare BW to bromide dilution as a method for estimating acute ΔECW. Finally, BIS was compared to DXA and single frequency bioimpedance analysis (SF-BIA) instruments to assess acute hydration effects on body composition estimates. During dehydration, no significant differences were found between bromide and BIS measures of ΔECW. The ΔECW measured by DXA (DXA-ΔECW) and BW (BW-ΔECW) was significantly different from bromide-estimated ΔECW (Br-ΔECW), but not from BIS estimates (BIS-ΔECW). During rehydration, there were no significant differences between Br-ΔECW and the other methods. When using BW as the reference, results were more consistent in that BW-ΔECW was significantly correlated with both BIS-ΔECW and DXA-ΔECW regardless of hydration status. These findings suggest that bromide may not be an appropriate criterion method for estimating short-term changes in hydration status. Regardless of hydration status, BIS provided accurate measures of fat-free mass (BIS-FFM) and fat mass (BIS-FM) that were comparable to, or better than, estimates by SF-BIA. At baseline and after dehydration BIS-FFM had the highest correlation with DXA estimates (DXA-FFM), although two SF-BIA instruments (Bio-Resistance Body Composition Analyzer from Valhalla Scientific and The Body Comp Scale from American Weights & Measures) produced good estimates of FFM. Rehydration appeared to affect the accuracy of FFM measurements by BIS and SF-BIA as evidenced by lower, more moderate correlations to DXA-FFM. Phase-dependent effects on percentage body fat (%BF) estimates were also apparent. In contrast, all methods performed reasonably well for estimates of FM, regardless of hydration status. In summary, BIS provides accurate estimates of ΔECW compared to either bromide dilution or BW, especially in the direction of dehydration. BIS also provides accurate estimates of FFM and FM regardless of hydration status. Further study of bromide dilution as a criterion measure is needed to validate its use in measuring ΔECW during acute shifts in hydration.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectHealth Sciences, Nutrition.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineNutritional Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHowell, Wanda H.en_US
dc.identifier.proquest3145074en_US
dc.identifier.bibrecord.b47210886en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.