Thea Suldrup Jørgensen

The Boost study: design of a school- and community-based randomised trial to promote fruit and vegetable consumption among teenagers

BackgroundThe aim of the Boost study was to produce a persistent increase in fruit and vegetable consumption among 13-year-olds. This paper describes the development, implementation and evaluation of a school-and community-based, multi-component intervention guided by theory, evidence, and best practice.Methods/designWe used the Intervention Mapping protocol to guide the development of the intervention. Programme activities combined environmental and educational strategies and focused on increasing access to fruit and vegetables in three settings: School: Daily provision of free fruit and vegetables; a pleasant eating environment; classroom curricular activities; individually computer tailored messages; one-day-workshop for teachers. Families: school meeting; guided child-parent activities; newsletters. Local community: guided visits in grocery stores and local area as part of classroom curriculum; information sheets to sports-and youth clubs.The Boost study employed a cluster-randomised controlled study design and applied simple two-stage cluster sampling: A random sample of 10 municipalities followed by a random sample of 4 schools within each municipality (N = 40 schools). Schools were randomised into a total of 20 intervention-and 20 control schools. We included all year 7 pupils except those from school classes with special needs. Timeline: Baseline survey: August 2010. Delivery of intervention: September 2010-May 2011. First follow-up survey: May/June 2011. Second follow-up survey: May/June 2012. Primary outcome measures: Daily mean intake of fruit and vegetables and habitual fruit and vegetable intake measured by validated 24-hour recall-and food frequency questionnaires. Secondary outcome measures: determinants of fruit and vegetable intake, positive side-effects and unintended adverse effects. Implementation was monitored by thorough process evaluation.DiscussionThe baseline data file included 2,156 adolescents (95%). There was baseline equivalence between intervention-and control groups for sociodemographics, primary outcomes, and availability at home, school and sports-and youth clubs. Significantly larger proportions of pupils in the control group had parents born in Denmark. The study will provide insights into effective strategies to increase fruit and vegetable intake among teenagers. The study will gain knowledge on implementation processes, intervention effects in population subgroups with low intake, and opportunities for including local communities in interventions.Trial registrationCurrent Controlled Trials ISRCTN11666034.

A six-step protocol to systematic process evaluation of multicomponent cluster-randomised health promoting interventions illustrated by the Boost study.

BACKGROUND In multicomponent interventions it is important to examine the implementation of each component to enable valid assessments of the effectiveness of each component. Many studies do not systematically document, evaluate and report the level of implementation and there is a lack of systematic approaches to conduct process evaluation studies to guide researchers and evaluators. The aim of this study was to present a systematic approach to plan process evaluation of the implementation of randomised multicomponent interventions. METHODS Building on existing process evaluation frameworks and concepts, we developed a six-step protocol: 1. Brainstorm of processes necessary for full implementation and potential barriers and facilitators to implementation; 2. Application of process evaluation concepts to ensure inclusion of important implementation processes; 3. Measurement of proximal outcomes; 4. Identification of relevant data sources; 5. Selection of methods and timing of data collection of process measures; 6. Development of instruments. The protocol was applied to the Boost study, a multicomponent school-based dietary intervention. RESULTS AND CONCLUSIONS The protocol was readily applicable for planning process evaluation of environmental and educational intervention components in a school setting. The protocol ensures systematic assessment of the implementation processes that are crucial for interpretation of intervention effects. TRIAL REGISTRATION Current Controlled Trials ISRCTN11666034.

Implementation of strategies to increase adolescents’ access to fruit and vegetables at school: process evaluation findings from the Boost study

BackgroundAccess to fruit and vegetables (FV) is associated with adolescents’ FV consumption. However, little is known about implementation of strategies to increase access to FV at schools. We examined the implementation of two environmental components designed to increase access to FV at Danish schools.MethodsWe used data from 20 intervention schools involved in the school-based multicomponent Boost trial targeting 13-year-olds’ FV consumption. The environmental components at school included daily provision of free FV and promotion of a pleasant eating environment.Questionnaire data was collected by the end of the nine-month intervention period among 1,121 pupils (95%), from all school principals (n = 20) and half way through the intervention period and by the end of the intervention among 114 teachers (44%).The implementation of the components was examined descriptively using the following process evaluation measures; fidelity, dose delivered, dose received and reach. Schools with stable high implementation levels over time were characterised by context, intervention appreciation and implementation of other components.ResultsFor all process evaluation measures, the level of implementation varied by schools, classes and over time. Dose received: 45% of pupils (school range: 13-72%, class range: 7-77%) ate the provided FV daily; 68% of pupils (school range: 40-93%, class range: 24-100%) reported that time was allocated to eating FV in class. Reach: The intake of FV provided did not differ by SEP nor gender, but more girls and low SEP pupils enjoyed eating FV together. Dose delivered: The proportion of teachers offering FV at a daily basis decreased over time, while the proportion of teachers cutting up FV increased over time. Schools in which high proportions of teachers offered FV daily throughout the intervention period were characterized by being: small; having a low proportion of low SEP pupils; having a school food policy; high teacher- and pupil intervention appreciation; having fewer teachers who cut up FV; and having high implementation of educational components.ConclusionsThe appliance of different approaches and levels of analyses to describe data provided comprehension and knowledge of the implementation process. This knowledge is crucial for the interpretation of intervention effect.Trial registrationCurrent Controlled Trials ISRCTN11666034

Implementing a free school-based fruit and vegetable programme: barriers and facilitators experienced by pupils, teachers and produce suppliers in the Boost study

BackgroundMulti-component interventions which combine educational and environmental strategies appear to be most effective in increasing fruit and vegetable (FV) intake in adolescents. However, multi-component interventions are complex to implement and often poorly implemented. Identification of barriers and facilitators for implementation is warranted to improve future interventions.This study aimed to explore implementation of two intervention components which addressed availability and accessibility of FV in the multi-component, school-based Boost study which targeted FV intake among Danish 13-year-olds and to identify barriers and facilitators for implementation among pupils, teachers and FV suppliers.MethodsWe conducted focus group interviews with 111 13-year-olds and 13 teachers, completed class observations at six schools, and conducted telephone interviews with all involved FV suppliers. Interviews were transcribed, coded and analysed using qualitative analytical procedures.ResultsFV suppliers affected the implementation of the FV programme at schools and thereby pupils’ intake through their timing of delivery and through the quality, quantity and variety of the delivered FV. Teachers influenced the accessibility and appearance of FV by deciding if and when the pupils could eat FV and whether FV were cut up. Different aspects of time acted as barriers for teachers’ implementation of the FV programme: time spent on having a FV break during lessons, time needed to prepare FV and time spent on pupils’ misbehaviour and not being able to handle getting FV. Teacher timing of cutting up and serving FV could turn into a barrier for pupils FV intake due to enzymatic browning. The appearance of FV was important for pupils’ intake, especially for girls. FV that did not appeal to the pupils e.g. had turned brown after being cut up were thrown around as a part of a game by the pupils, especially boys. Girls appreciated the social dimension of eating FV together to a larger extent than boys.ConclusionsLimited time and pupils’ misbehaviour were barriers for teachers’ implementation. Establishing FV delivery to schools as a new routine challenged FV suppliers’ implementation. Food aesthetics were important for most pupils’ FV intake while the social dimension of eating FV together seemed more important to girls than boys.Trial registrationCurrent Controlled Trials ISRCTN11666034.

Lunch frequency among adolescents: associations with sociodemographic factors and school characteristics

OBJECTIVE To investigate: (i) how lunch frequency of adolescents varies between schools and between classes within schools; (ii) the associations between frequency of lunch and individual sociodemographic factors and school characteristics; and (iii) if any observed associations between lunch frequency and school characteristics vary by gender and age groups. DESIGN Cross-sectional study in which students and school headmasters completed self-administered questionnaires. Associations were estimated by multilevel multivariate logistic regression. SETTING The Danish arm of the Health Behaviour in School-Aged Children study 2010. SUBJECTS Students (n 4922) aged 11, 13 and 15 years attending a random sample of seventy-three schools. RESULTS The school-level and class-level variations in low lunch frequency were small (intraclass correlation coefficient <2·1 %). At the individual level, low lunch frequency was most common among students who were boys, 13- and 15-year-olds, from medium and low family social class, descendants of immigrants, living in a single-parent family and in a reconstructed family. School-level analyses suggested that having access to a canteen at school was associated with low lunch frequency (OR=1·47; 95% CI 1·14, 1·89). Likewise not having an adult present during lunch breaks was associated with low lunch frequency (OR=1·44; 95% CI 1·18, 1·75). Cross-level interactions suggested that these associations differed by age group. CONCLUSIONS Lunch frequency among Danish students appears to be largely influenced by sociodemographic factors. Additionally, the presence of an adult during lunch breaks promotes frequent lunch consumption while availability of a canteen may discourage frequent lunch consumption. These findings vary between older and younger students.