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Bioelectrical impedance analysis to estimate body composition, and change in adiposity, in overweight and obese adolescents: comparison with dual-energy x-ray absorptiometry.

Wan CS, Ward LC, Halim J, Gow ML, Ho M, Briody JN, Leung K, Cowell CT, Garnett SP - BMC Pediatr (2014)

Bottom Line: The Tanita BIA8 manufacturers equations significantly (P < 0.001) overestimated FFM (4.3 kg [-5.3 to 13.9]) and underestimated %BF (-5.0% [-15 to 5.0]) compared to DXA.The mean differences between BIA derived equations and DXA measured body composition parameters were small (0.4 to 2.1%), not significant, but had large limits of agreements (~ ±15% for FFM).After the intervention mean %BF loss was similar by both methods (~1.5%), but with wide limits of agreement.

View Article: PubMed Central - PubMed

Affiliation: Institute of Endocrinology & Diabetes, The Children's Hospital at Westmead, Locked Bag 4001, Westmead NSW2145, Australia. sarah.garnett@health.nsw.gov.au.

ABSTRACT

Background: There is a need for a practical, inexpensive method to assess body composition in obese adolescents. This study aimed to 1) compare body composition parameters estimated by a stand-on, multi-frequency bioelectrical impendence (BIA) device, using a) the manufacturers' equations, and b) published and derived equations with body composition measured by dual-energy x-ray absorptiometry (DXA) and 2) assess percentage body fat (%BF) change after a weight loss intervention.

Methods: Participants were 66 obese adolescents, mean age (SD) 12.9 (2.0) years. Body composition was measured by Tanita BIA MC-180MA (Tanita BIA8) and DXA (GE-Lunar Prodigy). BIA resistance and reactance data at frequencies of 5, 50, 250 and 500 kHz, were used in published equations, and to generate a new prediction equation for fat-free mass (FFM) using a split-sample method. Approximately half (n = 34) of the adolescents had their body composition measured by DXA and BIA on two occasions, three to nine months apart.

Results: The correlations between FFM (kg), fat mass (kg) and %BF measured by BIA and DXA were 0.92, 0.93 and 0.78, respectively. The Tanita BIA8 manufacturers equations significantly (P < 0.001) overestimated FFM (4.3 kg [-5.3 to 13.9]) and underestimated %BF (-5.0% [-15 to 5.0]) compared to DXA. The mean differences between BIA derived equations and DXA measured body composition parameters were small (0.4 to 2.1%), not significant, but had large limits of agreements (~ ±15% for FFM). After the intervention mean %BF loss was similar by both methods (~1.5%), but with wide limits of agreement.

Conclusion: The Tanita BIA8 could be a valuable clinical tool to measure body composition at the group level, but is inaccurate for the individual obese adolescent.

No MeSH data available.


Related in: MedlinePlus

Mean-vs-difference plots of change in percent body fat (%fat) determined by dual-energy x-ray absorptiometry (DXA), compared to A) in-built Tanita BIA8equations and B) derived equation using the resistance index height2/R50(n = 34). ○ Boys ● Girls. ……. Limits of agreement (±1.96 SD) (dotted). ―Bias (solid). ----Line of best fit (short dash).
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Fig2: Mean-vs-difference plots of change in percent body fat (%fat) determined by dual-energy x-ray absorptiometry (DXA), compared to A) in-built Tanita BIA8equations and B) derived equation using the resistance index height2/R50(n = 34). ○ Boys ● Girls. ……. Limits of agreement (±1.96 SD) (dotted). ―Bias (solid). ----Line of best fit (short dash).

Mentions: The mean %BF loss measured of the 34 adolescents that had body composition measured on two occasions by DXA was -1.5% ± 4.0 and did not differ (-1.5% ± 4.4, P = 0.933) from that determined by the in-built Tanita BIA8 equations, albeit with wide limits of agreement, Figure 2a. The estimated %BF change derived from the equation based on RI H2/R50 was similar, -0.6% ± 2.4, but statistically different compared to the other estimates (P < 0.05), and showed significant bias; a strong association was observed whereby the loss of %BF was overestimated and gain in %BF was underestimated, Figure 2B. The correlation (rp) between change in %BF as measured by DXA was 0.69 and 0.78 for in-built Tanita BIA8 equations and the derived equation based on RI H2/R50, respectively. However, the strength of agreement between pairs of measures was poor; concordance correlations, rc = 0.69 and 0.66.Figure 2


Bioelectrical impedance analysis to estimate body composition, and change in adiposity, in overweight and obese adolescents: comparison with dual-energy x-ray absorptiometry.

Wan CS, Ward LC, Halim J, Gow ML, Ho M, Briody JN, Leung K, Cowell CT, Garnett SP - BMC Pediatr (2014)

Mean-vs-difference plots of change in percent body fat (%fat) determined by dual-energy x-ray absorptiometry (DXA), compared to A) in-built Tanita BIA8equations and B) derived equation using the resistance index height2/R50(n = 34). ○ Boys ● Girls. ……. Limits of agreement (±1.96 SD) (dotted). ―Bias (solid). ----Line of best fit (short dash).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4288657&req=5

Fig2: Mean-vs-difference plots of change in percent body fat (%fat) determined by dual-energy x-ray absorptiometry (DXA), compared to A) in-built Tanita BIA8equations and B) derived equation using the resistance index height2/R50(n = 34). ○ Boys ● Girls. ……. Limits of agreement (±1.96 SD) (dotted). ―Bias (solid). ----Line of best fit (short dash).
Mentions: The mean %BF loss measured of the 34 adolescents that had body composition measured on two occasions by DXA was -1.5% ± 4.0 and did not differ (-1.5% ± 4.4, P = 0.933) from that determined by the in-built Tanita BIA8 equations, albeit with wide limits of agreement, Figure 2a. The estimated %BF change derived from the equation based on RI H2/R50 was similar, -0.6% ± 2.4, but statistically different compared to the other estimates (P < 0.05), and showed significant bias; a strong association was observed whereby the loss of %BF was overestimated and gain in %BF was underestimated, Figure 2B. The correlation (rp) between change in %BF as measured by DXA was 0.69 and 0.78 for in-built Tanita BIA8 equations and the derived equation based on RI H2/R50, respectively. However, the strength of agreement between pairs of measures was poor; concordance correlations, rc = 0.69 and 0.66.Figure 2

Bottom Line: The Tanita BIA8 manufacturers equations significantly (P < 0.001) overestimated FFM (4.3 kg [-5.3 to 13.9]) and underestimated %BF (-5.0% [-15 to 5.0]) compared to DXA.The mean differences between BIA derived equations and DXA measured body composition parameters were small (0.4 to 2.1%), not significant, but had large limits of agreements (~ ±15% for FFM).After the intervention mean %BF loss was similar by both methods (~1.5%), but with wide limits of agreement.

View Article: PubMed Central - PubMed

Affiliation: Institute of Endocrinology & Diabetes, The Children's Hospital at Westmead, Locked Bag 4001, Westmead NSW2145, Australia. sarah.garnett@health.nsw.gov.au.

ABSTRACT

Background: There is a need for a practical, inexpensive method to assess body composition in obese adolescents. This study aimed to 1) compare body composition parameters estimated by a stand-on, multi-frequency bioelectrical impendence (BIA) device, using a) the manufacturers' equations, and b) published and derived equations with body composition measured by dual-energy x-ray absorptiometry (DXA) and 2) assess percentage body fat (%BF) change after a weight loss intervention.

Methods: Participants were 66 obese adolescents, mean age (SD) 12.9 (2.0) years. Body composition was measured by Tanita BIA MC-180MA (Tanita BIA8) and DXA (GE-Lunar Prodigy). BIA resistance and reactance data at frequencies of 5, 50, 250 and 500 kHz, were used in published equations, and to generate a new prediction equation for fat-free mass (FFM) using a split-sample method. Approximately half (n = 34) of the adolescents had their body composition measured by DXA and BIA on two occasions, three to nine months apart.

Results: The correlations between FFM (kg), fat mass (kg) and %BF measured by BIA and DXA were 0.92, 0.93 and 0.78, respectively. The Tanita BIA8 manufacturers equations significantly (P < 0.001) overestimated FFM (4.3 kg [-5.3 to 13.9]) and underestimated %BF (-5.0% [-15 to 5.0]) compared to DXA. The mean differences between BIA derived equations and DXA measured body composition parameters were small (0.4 to 2.1%), not significant, but had large limits of agreements (~ ±15% for FFM). After the intervention mean %BF loss was similar by both methods (~1.5%), but with wide limits of agreement.

Conclusion: The Tanita BIA8 could be a valuable clinical tool to measure body composition at the group level, but is inaccurate for the individual obese adolescent.

No MeSH data available.


Related in: MedlinePlus