Table 3

Multilevel regression analysis for body composition variables

Estimated % body fat±

Sum of skinfolds±

Waist circumference±


β

CI*

β

CI

β

CI


Constant

19.1

18.1, 20.1

20.8

19.2, 22.3

62.6

61.5,63.7

Sex¥

7.5

6.4, 8.5

5.0

3.3, 6.6

-1.2

-2.4,-0.03

Group**

1.3

0.1, 2.5

0.4

-1.5, 2.3

0.9

-0.5, 2.2

Age

0.8

0.7, 1.0

1.4

1.2, 1.7

2.3

2.1, 2.4

Age2

-0.2

-0.3, -0.03

-0.3

-0.6, -0.1

-0.2

-0.3, -.01

Group × Age2

0.2

-0.03, 0.4

0.3

0.0, 0.7

0.4

0.1, 0.6

School1

-1.8

-3.4, -0.1

n/a

-2.0

-3.8, -0.1

School4

3.5

0.8, 6.3

n/a


Random parts

variance

CI

variance

CI

variance

CI


Level 2 (Between individuals)

34.5

2.5, 29.6

89.0

6.4, 76.5

44.6

3.1, 38.5


Level 1 (Within individuals)

10.0

0.7, 8.6

25.5

1.8, 21.9

11.2

0.8, 9.7


BMI±

BMI-SDS±

β

CI

β

CI


Constant

17.8

17.3, 18.2

0.5

0.3, 0.6

Sex¥

0.4

-0.05, 0.9

-0.1

-0.2, 0.1

Group**

0.4

-0.03, 0.9

0.1

-0.04, 0.3

Age

0.6

0.6, 0.7

0.02

0.0, 0.04

Age2

-0.04

-0.1, 0.01

-0.03

-0.05, -0.01

Group × Age2

0.1

.05, 0.2

0.04

0.02, 0.1


Random parts

variance

CI

variance

CI


Level 2 (Between individuals)

7.5

0.5, 6.6

1.1

0.1, 1.0

Level 1 (Within individuals)

1.0

0.1, 0.9

0.1

0.01, 0.1


Notes:± The inclusion of SES did not improve the fit of the model and it was therefore not included.

*CI = 95% confidence interval; with level 2 variation (Between individuals) and with level 1 variation (within individuals or repeated measures)

= significant at p < 0.05;¥ Reference category = boys; ** reference category = control.

Gorely et al. International Journal of Behavioral Nutrition and Physical Activity 2011 8:74   doi:10.1186/1479-5868-8-74

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