Iris Kanera

144 Chapter 6 Table 6.1 Baseline characteristics of the KNW study sample ( N = 462) (Continued) Intervention group ( N = 231) Control group ( N = 231) p 1 Dietary behavior, M ( SD ) Vegetable intake, g p/d 138.5 (67.9) 124.2 (57.5) .015 Fruit intake, servings p/d 1.8 (1.2) 1.6 (1.0) .071 Whole grain bread, slices p/d 3.1 (1.8) 2.8 (1.5) .046 Fish intake, servings per week 1.9 (1.9) 1.4 (1.3) .001 Note: Abbreviations: BMI = Body Mass Index; M = mean; SD = standard deviation; KNW = Kanker Nazorg Wijzer 1 p-value for dichotomous variables from chi-square test; for continuous variables independent t-test 2 married, cohabiting partners 3 Low: lower vocational education, medium general secondary education; Medium: secondary vocational education, higher general secondary education; High: higher vocational education, university education. Main effects of the KNW on moderate physical activity after 12 months The reported values in Table 6.2 are raw scores that describe the course of moderate PA at baseline, after six months, and after 12 months. The within group changes are displayed from baseline to six months (IC: M 150.7 min p/w; UC: M 72.4 min p/w) and from baseline to 12 months (IC: M 92.2 min p/w; UC: M -14.3 min p/w). After six months, the difference between IC and UC was 78.3 min p/w, and after 12 months, the between group difference was 106.5 min p/w. Table 6.3 shows the results of the MLA. The between group differences in moderate PA after 12 months were statistically significant (complete cases: B = 128.475, p = .010; ITT: B = 129.473, p = .011) with an effect size of d = .35; f 2 = .013. Results remained significant after correction for multiple testing. Main effects of the KNW on vegetable consumption after 12 months The raw scores of the course of vegetable consumption at baseline, after six and 12 months are described in Table 6.2, as well as the within group changes after six months (IC: M 8.1 g p/d; UC: 0.7 g p/d), and after 12 months (IC: M -43.2 g p/d; UC: ‑42.8 g p/d). The between group changes were larger after six months (7.4 g p/d) compared to after 12 months (0.4 g p/d). Results from MLA revealed no significant intervention effect for vegetable consumption after 12 months ( B = 5.860, p = .121; ITT: B = 5.560, p = .132). This means, that the intervention effect on vegetable consumption after six months ( B = 11.799, p = .001; ITT: B = 11.606, p = .002) was not maintained (Table 6.3). Moderating effects of module use, gender, age and education Significant effect modification was found for age (β = -9.611, SE = 3.721 [95% CI = -16.90; -2.32], p = .010), indicating that the KNW effect on moderate PA was significantly more likely to be higher when participants were younger. Secondary analyses with a median split