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Table 4 Intervention effect at the end of the intervention and by intervention stage

From: A school-based intervention improved dietary intake outcomes and reduced waist circumference in adolescents: a cluster randomized controlled trial

  n Effect at the end of the intervention (28 months)a   Effect after stage 1 (17 months)b Effect after stage 2 (11 months)b  
Diffc (95% CI) P d ICCe Diffc(95% CI) P d Diff (95% CI) P d ICCf
Added sugar (g/d) 1046 −5.66 (−9.63;-1.65) 0.006 0.36 −2.72 (−6.97; 1.36) 0.20 −4.07 (−8.47; 0.44) 0.07 0.35
Fruit and vegetables (g/d) 1046 23.88 (7.36; 40.40) 0.005 0.26 29.2 (10.4; 47.6) 0.002 −13.4 (−37.4; 10.2) 0.27 0.26
Unhealthy snacking (g/d)g 1046 −23.32 (−45.25;-1.37) 0.04 0.16 −9.35 (−32.1; 13.4) 0.42 −18.5 (−44.8; 7.81) 0.17 0.17
Unhealthy snacking at school (PDh) 1046 −0.03 (−0.08; 0.06) 0.49 0.10 −0.15 (−0.20;-0.08) <0.001 0.11 (0.08; 0.50) 0.005 0.11
Breakfast intake (PDh) 1046 −0.03 (−0.06; 0.03) 0.39 0.42 0.03 (−0.005; 0.085) 0.11 −0.07 (−0.13;-0.02) 0.011 0.44
Fat (E%/d) 1046 −0.45 (−1.20; 0.31) 0.25 0.22 −0.51 (−1.36; 0.24) 0.17 0.11 (−0.77; 1.10) 0.74 0.21
Waist circumference (cm) 1079 −0.84 (−1.68;-0.28) 0.005 0.77 −1.68 (−2.38;-1.02) <0.001 0.66 (−0.07; 1.21) 0.08 0.78
  1. aResults obtained from mixed effects models accounting for the effects of clustering by individual and school. These models were adjusted for sex, UBN and differences at baseline (excluding the treatment group main effect) [35]
  2. bResults obtained from regressions spline mixed effects models. One knot was defined at the mean time of the first follow up data collection (17 months)
  3. cMean differences
  4. d P value
  5. eIntraclass correlation coefficient of mixed effects models
  6. fIntraclass correlation coefficient of regression spline mixed effects models
  7. gConsumption of unhealthy foods eaten during snack time; i.e. table sugar, sweets, salty snacks, fast food, soft drinks and packaged food
  8. hProportion difference