| Baseline§ | 3 months§ | p Value¶ | 7 months§ | p Value¶ | ||||
| Mean | SE | Mean | SE | Mean | SE | |||
| Sedentary behaviours | ||||||||
| Control | 256.3 | 26.5 | 256.8 | 25.4 | 258.8 | 25.5 | ||
| Intervention | 248.7 | 26.5 | 237.2 | 25.4 | 0.21 | 229.0 | 25.5 | 0.060 |
| Sedentary behaviours, on weekdays | ||||||||
| Control | 197.7 | 24.8 | 188.4 | 26.6 | 201.1 | 28.8 | ||
| Intervention | 181.3 | 24.8 | 172.2 | 26.6 | 0.21 | 169.8 | 28.8 | 0.02 |
| Sedentary behaviours, on weekend | ||||||||
| Control | 403.8 | 31.5 | 428.2 | 23.8 | 405.1 | 19.9 | ||
| Intervention | 419.7 | 31.4 | 399.3 | 23.7 | 0.25 | 377.5 | 19.7 | 0.25 |
| Computer | ||||||||
| Control | 43.6 | 11.4 | 52.0 | 11.9 | 59.2 | 11.0 | ||
| Intervention | 45.6 | 11.4 | 42.2 | 11.9 | 0.13 | 43.0 | 11.0 | 0.016 |
| Computer, on weekdays | ||||||||
| Control | 26.7 | 8.9 | 31.2 | 9.1 | 39.7 | 8.8 | ||
| Intervention | 25.1 | 8.9 | 22.8 | 9.1 | 0.07 | 23.3 | 8.8 | 0.0009 |
| Computer, on weekend | ||||||||
| Control | 85.9 | 17.7 | 104.1 | 19.0 | 107.7 | 16.7 | ||
| Intervention | 97.1 | 17.7 | 90.7 | 19.0 | 0.27 | 91.9 | 16.7 | 0.18 |
| Television and DVD | ||||||||
| Control | 70.7 | 12.5 | 72.2 | 9.5 | 69.0 | 11.2 | ||
| Intervention | 65.6 | 12.5 | 60.9 | 9.5 | 0.13 | 65.1 | 11.2 | 0.56 |
| Video game | ||||||||
| Control | 6.0 | 1.3 | 10.3 | 1.8 | 11.9 | 1.9 | ||
| Intervention | 7.8 | 1.2 | 7.6 | 1.8 | 0.26 | 8.5 | 1.9 | 0.21 |
| Extracurricular reading, writing, drawing and listening to music | ||||||||
| Control | 83.6 | 4.1 | 74.1 | 5.0 | 79.4 | 4.8 | ||
| Intervention | 81.3 | 4.1 | 79.6 | 4.9 | 0.4 | 72.6 | 4.8 | 0.29 |
| Passive commuting | ||||||||
| Control | 31.6 | 2.6 | 27.8 | 2.7 | 25.6 | 2.5 | ||
| Intervention | 27.4 | 2.6 | 32.4 | 2.6 | 0.22 | 29.3 | 2.5 | 0.32 |
| Sitting and talking | ||||||||
| Control | 22.3 | 3.0 | 21.4 | 1.8 | 16.8 | 1.7 | ||
| Intervention | 24.2 | 2.9 | 17.0 | 1.8 | 0.16 | 14.2 | 1.6 | 0.34 |
↵* Information on daily time spent on sedentary behaviours was collected with an 8-item scale by weekdays and weekend, including TV viewing; DVD viewing; computer usage; playing video games; extracurricular reading; extracurricular writing, drawing and listening to music; being a passenger in a bicycle, a subway, a bus or a car; sitting and talking (face-to-face or by phone). Total sedentary behaviours are the sum of the 8 items.
↵† Comparison between control group and intervention group in each variable at baseline is not significant.
↵‡ Sample size in control group is 336 and in intervention group is 345.
↵§ Data were adjusted for age, gender and body mass index at baseline.
↵¶ Comparison between intervention and control groups was adjusted for age, gender, body mass index at baseline, interaction between measurement time and groups, and cluster effect in randomisation pair, school and class level, within-subject correlation using PROC GLIMMIX procedure in SAS V.9.2.