Mean baseline physical activity and sedentary behaviour outcomes (±SD), modelled changes (95% CI) from baseline for each group, interaction p value and the main effects (95% CI) of physical activity and sedentary behaviour at 18 and 30 months
| Outcome | N | Control group | n | PA-I group | N | SB-I group | n | PA+SB I group | PA×SB interaction (P value) | Main effects (if interaction not significant) or intervention effects (comparison between each experimental group and the control group) if interaction significant | ||
| PA intervention | SB intervention | PA+SB intervention | ||||||||||
| Sedentary time (min/weekday) | ||||||||||||
| Baseline | 89 | 327±72 | 97 | 322±64 | 81 | 342±57 | 75 | 328±74 | ||||
| Change at 18 months | 38 | 29.8 (−35.1 to 95.1) | 53 | −4.1 (−67.7 to 59.5) | 43 | 11.2 (−53.0 to 75.5) | 41 | −0.5 (−64.7 to 63.6) | p=0.237 | −27.0* (−47.3 to –5.3) | −5.7 (−27.4 to 15.1) | NA |
| Change at 30 months | 44 | 49.3 (−15.6 to 114.2) | 47 | 31.3 (−33.1 to 95.6) | 33 | −13.7 (−77.3 to 50.0) | 31 | 19.0 (−49.1 to 87.0) | 56.4** (15.8 to 96.4) | −18.9 (−45.6 to 9.2) | −62.8*** (−92.0 to –33.9) | −25.4 (−55.5 to 4.7) |
| Sedentary time (min/average day) | ||||||||||||
| Baseline | 89 | 334±67 | 97 | 339±63 | 81 | 351±53 | 75 | 344±71 | ||||
| Change at 18 months | 38 | 22.4 (−35.4 to 80.1) | 53 | 28.7 (−55.6 to 57.1) | 43 | 12.9 (−43.8 to 69.5) | 41 | 5.1 (−51.7 to 69.8) | p=0.132 | −16.5 (−33.8 to 0.78) | −2.1 (−18.8 to 14.5) | NA |
| Change at 30 months | 44 | 51.7 (−5.5 to 109.0) | 47 | 38.8 (−18.0 to 95.5) | 33 | 1.2 (−54.8 to 57.2) | 31 | 22.6 (−34.5 to 80.0) | 2.43 (−14.3 to 19.2) | −33.3*** (−50.6 to –16.0) | NA | |
| Sedentary breaks (frequency/weekday) | ||||||||||||
| Baseline | 89 | 313±41 | 97 | 311±39 | 81 | 318±48 | 75 | 318±45 | ||||
| Change at 18 months | 38 | 40.8 (−0.3 to 81.8) | 53 | 35.5 (−4.6 to 75.6) | 43 | 30.3 (−10.0 to 70.5) | 41 | 32.4 (−8.0 to 72.8) | p=0.530 | −2.4 (−14.7 to 9.9) | −6.0 (−17.9 to 5.9) | NA |
| Change at 30 months | 44 | 20.0 (−21.0 to 60.6) | 47 | 31.6 (−8.8 to 72.1) | 33 | 34.6 (−5.2 to 74.5) | 31 | 17.4 (−23.3 to 58.0) | −29.09* (−51.36 to –5.40) | 11.8 (−4.34 to 28.0) | 14.8 (−2.4 to 32.1) | −2.4 (−20.0 to 15.1) |
| Sedentary breaks (frequency/average day) | ||||||||||||
| Baseline | 89 | 313±39 | 97 | 310±34 | 81 | 315±45 | 75 | 316±41 | ||||
| Change at 18 months | 38 | 37.0* (0.5 to 73.5) | 53 | 40.7* (4.9 to 76.4) | 43 | 32.2 (−3.5 to 67.8) | 41 | 36.7* (0.7 to 72.6) | p=0.094 | 3.4 (−7.0 to 13.7) | −4.2 (−14.2 to 5.8) | NA |
| Change at 30 months | 44 | 21.1 (−15.0 to 57.3) | 47 | 32.1 (−3.8 to 67.9) | 33 | 34.9 (−0.4 to 70.1) | 31 | 22.4 (−13.7 to 58.6) | 0.6 (−9.4 to 10.6) | 2.0 (−8.4 to 12.4) | NA | |
| Moderate-to-vigorous intensity physical activity (min/weekday) | ||||||||||||
| Baseline | 89 | 69±19 | 97 | 64±20 | 81 | 67±19 | 75 | 66±19 | ||||
| Change at 18 months | 38 | −16.9 (−38.2 to 4.4) | 53 | −18.2 (−39.0 to 2.6) | 43 | −16.8 (−37.6 to 4.1) | 41 | −11.7 (−32.7 to 9.2) | p=0.438 | 1.6 (−4.6 to 7.8) | 3.5 (−2.5 to 9.5) | NA |
| Change at 30 months | 44 | −18.9 (−40.1 to 2.2) | 47 | −17.2 (−38.1 to 3.7) | 33 | −27.8** (−48.4 to 7.2) | 31 | −17.2 (−38.3 to 3.8) | 5.8 (−0.3 to 11.8) | −4.5 (−10.8 to 1.7) | NA | |
| Moderate-to-vigorous intensity physical activity (min/average day) | ||||||||||||
| Baseline | 89 | 69±27 | 97 | 62±20 | 81 | 67±19 | 75 | 66±19 | ||||
| Change at 18 months | 38 | −20.8* (−40.3 to −1.4) | 53 | −22.4* (−41.4 to −3.3) | 43 | −15.9 (−34.9 to 3.2) | 41 | −16.3 (−35.4 to 2.9) | p=0.964 | −1.1 (−6.6 to 4.5) | 5.5* (0.1 to 10.8) | NA |
| Change at 30 months | 44 | −23.9* (−43.2 to −4.6) | 47 | −23.3* (−42.4 to −4.2) | 33 | −29.0** (−47.8 to −10.1) | 31 | −26.4** (−45.7 to −7.1) | 1.5 (−3.8 to 6.9) | −4.2 (−9.7 to 1.3) | NA | |
Significant intervention effects bolded. All estimates of group-specific changes from baseline and intervention effects are adjusted for school socioeconomic status, child’s age and sex, number of valid days of accelerometry data, average daily minutes of wear time, baseline outcome value and season in which the assessment was conducted (spring, summer, autumn and winter). Intervention effects estimated according to intention-to-treat whereby all participants with valid baseline outcome data were included in the analyses. Only main effects of PA and SB are reported because the interaction effect of PA and SB interventions was not significant. These represent the adjusted average difference in change from baseline between participants receiving the PA or SB intervention and those not receiving the interventions. If the interaction of PA and SB interventions was significant, then main effects were not reported. *p<0.05; **p<0.01; ***p<0.001.
moderate-to-vigorous intensity physical activity, corresponding to 4-6 METs; n, number of observations at specific time points; NA, not applicable; ns interact, interaction effect of PA and SB interventions not significant at a specific time point (p value of interaction term); PA-I, physical activity (PA) promotion group; PA+SB-I, combination of PA-I and SB-I; SB-I, reducing sedentary behaviour (SB) group; Sedentary breaks, frequency of occasions exceeding 100 cpm; Sedentary time, <100 counts per min (cpm).