Page 86 - ON THE WAY TO HEALTHIER SCHOOL CANTEENS - Irma Evenhuis

Chapter 5. Effect evaluation
Table 5.3. Weekly food and drink purchases in the cafeteria.
Weekly purchases of less healthy products, mean (SD)
Weekly purchases of healthier products, mean (SD)
Bought healthier products of total bought products, %
Changes in purchases per week over time
Healthy score a, %
1.50 (3.84)
0.85 (2.98)
36.2%
0.92 (1.39)
0.51 (2.23)
35.7%
1.41 (2.11)
0.80 (1.82)
36.2%
1.39 (4.20)
1.17 (3.75)
45.7%
1.43 (2.63)
0.82 (2.83)
36.4%
1.72 (4.97)
1.17 (4.38)
40.5%
0.91 (1.34)
0.46 (1.10)
33.6%
1.04 (3.71)
0.59 (3.78)
36.2%
Intervention schools Control schools
Boys (n=276) Girls (n= 308) Boys (n=272) Girls (n=357) T0 T1 T0 T1 T0 T1 T0 T1
50.0%
53.6%
51.5%
46.5%
a From each student, the difference between T0 and T1 has been calculated. Equal or bigger change in healthier products compared to less healthy products has been defined as a healthy score.
Table 5.4. Weekly food and drink purchases at the vending machine.
Intervention schools Control schools
Boys (n=270) Girls (n= 311) Boys (n=272) Girls (n=364) T0 T1 T0 T1 T0 T1 T0 T1
Weekly purchases of less healthy products, mean (SD)
Weekly purchases of healthier products, mean (SD)
Bought healthier products of total bought products, %
Changes in purchases per week over time
Healthy score a, %
1.41 (3.03)
1.11 (3.13)
44.1%
0.88 (2.34)
0.79 (2.36)
47.3%
1.60 (2.84)
1.43 (2.40)
47.2%
1.40 (3.31)
1.48 (3.59)
51.4%
1.51 (2.44)
1.26 (2.59)
45.5%
1.40 (4.21)
1.13 (2.85)
44.7%
0.94 (1.78)
0.97 (1.49)
50.8%
0.83 (1.37)
0.87 (1.45)
51.2%
49.3%
47.3%
49.3%
51.6%
a From each student, the difference between T0 and T1 has been calculated. Equal or bigger change in healthier products compared to less healthy products has been defined as a healthy score.
Purchase behaviour analysed by mixed logistic regression analyses
The results of the performed mixed logistic regression analyses showed that the odds for a healthier purchase behaviour compared to less healthy purchase behaviour is approximately equal for students in the intervention and control schools (Table 5.5). In boys, we found odds ratios of 0.92 (95% CI 0.62; 1.36) for cafeteria purchases and 1.02 (95% CI 0.62; 1.67) for vending machine purchases. Girls showed an odds ratio of 1.29 (95% CI 0.85; 1.96) for the cafeteria and 0.84 (95% CI 0.62; 1.14) in vending machines purchases. Adjustment for demographic (model 2), behavioural (model 3) and environmental variables (model 4) did not materially change the results.
The analyses to the effect of a healthier canteen (healthier versus less healthy (ref. group) availability in the cafeteria, vending machine or accessibility) on purchase behaviour showed OR‘s ranging from 0.87 (95% CI 0.61–1.26) for combined purchases in girls, to
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