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Table 1 Traditional and compositional isotemporal substitution: Estimated absolute differences in body fat% associated with 30-min pair-wise reallocations between activity behaviours

From: Adiposity and the isotemporal substitution of physical activity, sedentary time and sleep among school-aged children: a compositional data analysis approach

BOYS n = 760

Model

Body fat%

Sleep

SED

LPA

MVPA

 

30 min

∆‘

95% CI

∆‘

95% CI

∆‘

95% CI

∆‘

95% CI

Traditional

Sleep

  

−0.29

−0.56, −0.01

−0.56

−0.92, −0.20

1.38

0.78, 2.00

Compositional

   

−0.20

−0.46, 0.05

−0.53

−0.87, −0.18

2.11

1.37, 2.85

Traditional

SED

0.29

0.01, 0.56

  

−0.27

−0.58, 0.03

1.67

1.13, 2.22

Compositional

 

0.20

−0.05, 0.46

  

−0.33

−0.63, −0.02

2.31

1.62, 2.99

Traditional

LPA

0.56

0.20, 0.92

0.27

−0.03, 0.58

  

1.95

1.26, 2.63

Compositional

 

0.49

0.16, 0.83

0.28

−0.01, 0.57

  

2.60

1.78, 3.42

Traditional

MVPA

−1.38

−2.00, −0.78

−1.67

−2.22, −1.13

−1.95

−2.63, −1.26

  

Compositional

 

−1.33

−1.83, −0.82

−1.54

−1.99, −1.09

−1.86

−2.46, −1.26

  

GIRLS n = 968

Model

Body fat%

Sleep

SED

LPA

MVPA

 

30 min

∆‘

95% CI

∆‘

95% CI

∆‘

95% CI

∆‘

95% CI

Traditional

Sleep

  

−0.55

−0.85, −0.25

−0.49

−0.85, −0.12

1.60

0.80, 2.39

Compositional

   

−0.52

−0.80, −0.24

−0.49

−0.85, −0.12

2.44

1.34, 3.54

Traditional

SED

0.55

0.25, 0.85

  

0.07

−0.25, 0.38

2.15

1.41, 2.89

Compositional

 

0.52

0.24, 0.80

  

0.02

−0.30, 0.34

2.94

1.89, 4.00

Traditional

LPA

0.49

0.12, 0.85

−0.07

−0.38, 0.25

  

2.08

1.20, 2.97

Compositional

 

0.47

0.13, 0.82

−0.06

−0.36, 0.24

  

2.90

1.70, 4.10

Traditional

MVPA

−1.60

−2.39, −0.80

−2.15

−2.89, −1.41

−2.08

−2.97, −1.20

  

Compositional

 

−1.24

−1.88, −0.61

−1.78

−2.36, −1.19

−1.74

−2.50, −0.99

  
  1. Abbreviations: estimated difference in body fat%, CI confidence interval, SED sedentary time, LPA light physical activity, MVPA moderate-to-vigorous physical activity. Analysis adjusted for parental education level and number of parents and siblings. Note: Difference in body fat% is estimated for the reallocation of time from the behaviour in the column to the behaviour in the row, i.e., the first value of −0.29 in Row 1 is the estimated difference in body fat% for the reallocation of 30 min from sedentary time to sleep among boys. Boys’ mean daily activity composition (min/day): Sleep = 550; SED = 510; LPA = 308; MVPA = 72. Mean body fat% for boys: \( \overline{x} \) = 18.1. Girls’ mean daily activity composition (min/day): Sleep = 564; SED = 520; LPA = 301; MVPA = 55. Mean body fat% for girls: \( \overline{x} \) = 22.3