Teun Remmers

60 | Chapter 4 Associates of OP development between child age five and seven Child age, child and parental ethnic background, parental attitude, family attitude, intention to improve, the presence of rules and positive modelling of siblings were included in the models, presented in Table 4, as these variables showed significant univariate associations (i.e. p > 0.10). This means that none of the variables within perceived PE were related to OP (i.e. change between child age five and seven). Regarding socio-demographic variables, child age at baseline was related to a significant change in OP between baseline and follow-up (Table 4; p < 0.05). This was possible as all children were not precisely five years old at baseline. This means that a higher child age was related to higher engagement in OP at baseline, but that this attenuated significantly over time. Regarding family environment, the intention to improve OP and the presence of rules were both associated with a decrease of OP over time compared to baseline (i.e. Table 2). This means that modelling of sibling was related to higher engagement in OP at baseline, but that this attenuated significantly over time. Table 4: Linear mixed models examining factors related to child outside play development between age five and seven (min/day) Adjusted effect* at baseline Adjusted effect* at 2 years follow-up p for time interaction n =1552 Socio-demographics Child age at baseline 26.17 (19.19 to 33.14) 5.71 (−2.57 to 13.99) < 0.01 Child ethnic background; Dutch −3.03 (−18.47 to 12.40) −1.22 (−18.73 to 16.28) 0.86 Parental ethnic background; Dutch 21.28 (0.56 to 42.00) 8.19 (−15.79 to 32.17) 0.36 Family environment 1 Parental attitude (agree) −5.83 (−9.32 to −2.34) −5.74 (−9.95 to −1.52) 0.97 Family attitude (agree) −5.07 (−8.67 to −1.47) −3.59 (−7.88 to 0.70) 0.56 Intention to improve (agree) −11.33 (−18.01 to −4.66) −4.34 (−12.15 to 3.46) 0.14 Presence of rules 29.71 (23.89 to 35.54) 23.85 (17.04 to 30.66) 0.15 Modelling siblings (# days physically active) 7.56 (5.76 to 9.36) 3.95 (1.87 to 6.03) < 0.01 1 : For details on the measures used see Table S1 in Appendix 1. *Adjusted for season, age at baseline and follow- up. Adjusted effects are not exactly equal to results in Tables 2 and 3 because of differences in included covariates, and model specifications. Note: numbers printed bold represent statistically significant associations between the predictor and child outside play.