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Table 2 Body composition parameters determined by dual-energy x-ray absorptiomtry, in-built Tanita BIA 8 equations, and published equations

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

Method

DXA

Tanita BIA8

Ramirez et al. [[11]]

Bray et al. [[12]]

Jaffrin et al. [[14]]

Fat-free mass kg

Mean ± SD (kg)

47.4 ± 11.7

51.7 ± 12.1a

48.0 ± 11.1

47.8 ± 9.8

48.3 ± 11.5

Bias (kg)

 

4.3

0.6

0.4

0.9

Limits of agreement (kg)

 

-5.3 to 13.9

-7.1 to 8.2

-7.6 to 8.4

-6.2 to 8.0

r c (95% CI)b

 

0.86 (0.79 – 0.91)

0.94 (0.90 – 0.96)

0.93 (0.89– 0.6)

0.95 (0.92 – 0.97)

Fat mass kg

Mean ± SD (kg)

41.8 ± 12.1

37.5 ± 13.0a

41.2 ± 11.5

41.3 ± 12.2

40.9 ± 11.6

Bias (kg)

 

-4.3

-0.6

-0.5

-0.9

Limits of agreement (kg)

 

-13.9 to 5.3

-8.2 to 7.1

8.4 to -7.6

8.0 to -6.2

r c (95% CI)b

 

0.87 (0.81 – 0.92)

0.94 (0.91 – 0.96)

0.94 (0.91 – 0.96)

0.95 (0.92 – 0.97)

Percentage of body fat

Mean ± SD (%)

46.4 ± 7.4

41.4 ± 8.3a

45.8 ± 5.5

45.7 ± 5.2

45.6 ± 6.0

Bias (%)

 

-5.0

-0.6

-0.5

-0.8

Limits of agreement (%)

 

-15.1 to 5.0

-9.1 to 7.9

-9.2 to 8.0

-9.2 to 7.4

r c (95% CI)b

-

0.65 (0.53 – 0.75)

0.77 (0.67 - 0.85)

0.76 (0.65 – 0.83)

0.79 (0.69 – 0.86)

  1. adifference between DXA and Tanita BIA8, P <0.001.
  2. bCI: confidence interval.