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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