The role of curriculum dose for the promotion of fruit and vegetable intake among adolescents: results from the Boost intervention

Abstract

BackgroundMulti-component interventions combining educational and environmental strategies have proved effective in increasing children and adolescents’ fruit and vegetable intake. However such interventions are complex and difficult to implement and several studies report poor implementation. There is a need for knowledge on the role of dose for behaviour change and for assessment of intervention dose to avoid conclusions that intervention components which are not implemented are ineffective. This study aimed to examine 1) the association between dose of a class curriculum and adolescents’ fruit and vegetable intake in a school-based multi-component intervention, 2) if gender and socioeconomic position modify this association.MethodsWe carried out secondary analysis of data from intervention schools in the cluster-randomized Boost study targeting 13-year-olds’ fruit and vegetable intake. Teacher- and student data on curriculum dose delivered and received were aggregated to the school-level and class-level (only possible for student data). We analysed the association between curriculum dose and students’ (n 995) self-reported fruit and vegetable intake (24-h recall questionnaire) after finalization of the intervention using multi-level analyses. Potential moderation was examined by analyses stratified by gender and socioeconomic position.ResultsAverage dose received at class-level was significantly associated with students’ fruit and vegetable intake (10 g (CI: 0.06, 20.33) per curricular activity received). In stratified analyses the association remained significant among boys only (14 g (CI: 2.84, 26.76) per curricular activity received). The average dose delivered and received at the school-level was not significantly associated with students’ intake.ConclusionsWe found a dose—response relationship between number of curricular activities received and adolescents’ fruit and vegetable intake. The results indicate that curriculum dose received only mattered for promotion of fruit and vegetable intake among boys. Future studies should explore this gender difference in larger samples to guide the planning of school-based curricular interventions with regards to the optimal number of curricular activities required to promote behavioural change in subgroups with low fruit and vegetable intake at baseline.Trial registrationCurrent Controlled Trials ISRCTN11666034.

Measuring implementation fidelity of school-based obesity prevention programmes: a systematic review

“…Level of evaluation NA 3. Operationalisation fidelity component N = 15 [ 28 , 29 , 35 – 38 , 46 – 49 , 51 , 56 , 59 – 61 , 69 , 71 , 72 , 77 , 87 ] 4. Data collection methods N = 8 [ 29 , 47 – 49 , 60 , 68 , 70 , 86 , 90 ] 5.…”

“…Data collection methods N = 8 [ 29 , 47 – 49 , 60 , 68 , 70 , 86 , 90 ] 5. Quantitative fidelity measures N = 13 [ 25 , 28 , 36 – 38 , 46 – 49 , 51 , 56 , 60 , 68 , 71 , 72 , 77 , 81 , 87 ] 6. Frequency of data collection N = 22 [ 24 , 28 , 29 , 32 , 35 – 38 , 44 , 46 , 48 , 51 , 56 , 60 , 61 , 68 – 72 , 77 , 81 , 85 – 87 , 90 ] 7.…”

“…Quantitative fidelity measures N = 13 [ 25 , 28 , 36 – 38 , 46 – 49 , 51 , 56 , 60 , 68 , 71 , 72 , 77 , 81 , 87 ] 6. Frequency of data collection N = 22 [ 24 , 28 , 29 , 32 , 35 – 38 , 44 , 46 , 48 , 51 , 56 , 60 , 61 , 68 – 72 , 77 , 81 , 85 – 87 , 90 ] 7. Relation fidelity component and programme outcome assessed N = 5 [ 25 , 28 , 29 , 46 , 56 , 81 ] Methodological qualitsy per fidelity component • Low (< 50%) N = 11 [ 24 , 25 , 30 , 32 , 35 , 44 , 59 , 69 , 70 , …”

Curricular activities and change in determinants of fruit and vegetable intake among adolescents: Results from the Boost intervention

“…Future analyses should examine if this effect can be explained by the free daily provision of FV at class. The role of curriculum dose on actual FV intake self-reported by students has been shown (Jørgensen et al, 2015). …”

“…Potentially, some schools may have been misclassified with a lower number of activities than were actually implemented. For thorough discussions of methodological issues related to curriculum dose in the Boost intervention, see Jørgensen et al (2015). It may be difficult for students to remember activities implemented in the beginning of the intervention period when asked at the end.…”