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

Krølner R, Suldrup Jørgensen T, Aarestrup AK, Hjøllund Christiansen A, Christensen AM, Due P - BMC Public Health (2012)

Bottom Line: Daily mean intake of fruit and vegetables and habitual fruit and vegetable intake measured by validated 24-hour recall-and food frequency questionnaires. determinants of fruit and vegetable intake, positive side-effects and unintended adverse effects.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Intervention Research in Health Promotion and Disease Prevention, University of Southern Denmark, National Institute of Public Health, Øster Farimagsgade, Copenhagen K, Denmark. rkr@niph.dk

ABSTRACT

Background: The 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/design: We 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.

Discussion: The 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.

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Flow diagram of sampling, recruitment, randomisation and participation in the Boost study.
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Figure 2: Flow diagram of sampling, recruitment, randomisation and participation in the Boost study.

Mentions: Figure 2 shows the flow of the sampling process. We decided on a study design with ten municipalities with two intervention-and two control schools within each municipality. By this study design we aimed at making intervention-and control schools comparable as schools within the same municipality are exposed to the same political context (local health policies and political standpoints). The inclusion of ten municipalities only also reduced travel costs and made fieldwork feasible (e.g. data collection and thorough process evaluation at schools). A simple two-stage cluster sampling process was applied beginning with a random sample of municipalities (sampling frame: list of all 98 municipalities in Denmark, exclusion criteria: Less than four public schools), followed by a random sample of municipal schools (sampling frame: lists of all schools in selected municipalities). Eligible schools had minimum two school classes of year 7 pupils, exclusion criteria: special needs schools, and private schools. Using a computer-generated list of random numbers we randomly ranked Danish municipalities and the schools within them. The first ten municipalities from the randomly ordered municipal list were selected and within each of them the first four schools from the randomly ordered school lists were drawn. By telephone, principals were invited to take part in the study. They received a letter with factsheets addressing the school administration, teachers, parent board, and pupil council immediately after the telephone conversation. Schools accepting to participate were asked to sign a written contract disregarding the result of the randomisation. In one of the included municipalities a school refused to participate due to involvement in too many projects and was replaced by a new school from the list. To ensure sufficient exposure contrast, one of the sampled municipalities in which schools already had a free FV programme, was excluded. A random sample of schools from the next municipality on the list of randomly selected municipalities was approached and all schools contacted in this municipality accepted to participate.


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

Krølner R, Suldrup Jørgensen T, Aarestrup AK, Hjøllund Christiansen A, Christensen AM, Due P - BMC Public Health (2012)

Flow diagram of sampling, recruitment, randomisation and participation in the Boost study.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3375189&req=5

Figure 2: Flow diagram of sampling, recruitment, randomisation and participation in the Boost study.
Mentions: Figure 2 shows the flow of the sampling process. We decided on a study design with ten municipalities with two intervention-and two control schools within each municipality. By this study design we aimed at making intervention-and control schools comparable as schools within the same municipality are exposed to the same political context (local health policies and political standpoints). The inclusion of ten municipalities only also reduced travel costs and made fieldwork feasible (e.g. data collection and thorough process evaluation at schools). A simple two-stage cluster sampling process was applied beginning with a random sample of municipalities (sampling frame: list of all 98 municipalities in Denmark, exclusion criteria: Less than four public schools), followed by a random sample of municipal schools (sampling frame: lists of all schools in selected municipalities). Eligible schools had minimum two school classes of year 7 pupils, exclusion criteria: special needs schools, and private schools. Using a computer-generated list of random numbers we randomly ranked Danish municipalities and the schools within them. The first ten municipalities from the randomly ordered municipal list were selected and within each of them the first four schools from the randomly ordered school lists were drawn. By telephone, principals were invited to take part in the study. They received a letter with factsheets addressing the school administration, teachers, parent board, and pupil council immediately after the telephone conversation. Schools accepting to participate were asked to sign a written contract disregarding the result of the randomisation. In one of the included municipalities a school refused to participate due to involvement in too many projects and was replaced by a new school from the list. To ensure sufficient exposure contrast, one of the sampled municipalities in which schools already had a free FV programme, was excluded. A random sample of schools from the next municipality on the list of randomly selected municipalities was approached and all schools contacted in this municipality accepted to participate.

Bottom Line: Daily mean intake of fruit and vegetables and habitual fruit and vegetable intake measured by validated 24-hour recall-and food frequency questionnaires. determinants of fruit and vegetable intake, positive side-effects and unintended adverse effects.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Intervention Research in Health Promotion and Disease Prevention, University of Southern Denmark, National Institute of Public Health, Øster Farimagsgade, Copenhagen K, Denmark. rkr@niph.dk

ABSTRACT

Background: The 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/design: We 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.

Discussion: The 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.

Show MeSH