Plain English Summary
Background and study aims
The Dutch Obesity Intervention in Teenagers (DOiT) is a school-based program to prevent weight gain in 12 to 14 year old students. We are carrying out a study at 20 schools implementing the DOiT program to compare the quality of implementation of the program. Our goal is to find factors that help or hinder the DOiT program so that we can adjust the strategy of the program and thereby prevent weight gain in Dutch adolescents.
Who can participate?
Teachers, students and their parents at prevocational schools in the Netherlands.
What does the study involve?
Participating schools are randomly allocated to either the intervention group or the control group. Students at the intervention group schools participate in the DOiT program. Students at the control group schools receive regular education. Before the start of the DOiT program and after 20 months, we measure the students’ body weight, height, skinfold thickness, waist and hip circumference, and students complete a diet and physical activity questionnaire. After each DOiT lesson teachers complete a log, and at the start of the study and after 10 and 20 months teachers complete a questionnaire about the factors that help or hinder the implementation of DOiT. At the end of each school year a subgroup of teachers and the coordinator are invited for an in-depth interview to gain more insight into the implementation of the DOiT program.
What are the possible benefits and risks of participating?
Students who take part in the DOiT lessons will be supported to change their diet and physical activity levels. There are no risks to participants.
Where is the study run from?
At prevocational schools throughout the Netherlands.
When is the study starting and how long is it expected to run for?
February 2011 to July 2013.
Who is funding the study?
SNS REAAL Fonds, The Netherlands.
Who is the main contact?
Femke van Nassau
Exploring facilitating factors and barriers to the nationwide dissemination of a Dutch school-based weight gain prevention program "DOiT"
It is hypothesised that the students who receive the fully implemented DOiT program will be less overweight and will have more healthy energy-balance related behaviours compared to students who receive regular education at the control schools.
VU University Medical Center Ethics Board, 11/07/2011 ref: 2011/216
Primary study design
Secondary study design
Cluster randomised trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
DOiT is a school-based overweight prevention program for 12 to 14-year olds. DOiT focuses on five EBRBs:
1. Reducing intake of sugar-sweetened beverages
2. Reducing intake of high-energy snacks
3. Reducing screen time
4. Increasing levels of physical activity (i.e. active transport and sports participation)
5. Daily and healthy breakfast consumption
The program consists of a classroom, an environmental and a parental component. The program covers twelve fixed theory lessons, four physical education (PE) lessons, equally divided over two school years,
and three optional additional lessons.
1. The theory lessons in year one aim to increase awareness and knowledge of EBRBs. The lessons in year two focus on the influence of the (obesogenic) environment.
2. The environmental component aims to raise awareness of the school environment, finding solutions to reduce negative influences within the environment and setting a plan for improvement.
3. The parental component focuses on stimulating social support of the parents and raising awareness of the availability and accessibility of healthy products and activities in the home environment.
The DOiT materials include a 'schoolbook' accompanied by worksheets, a student toolkit (pedometer, food/exercise diary and an online computer-tailored advice) and a parental information booklet.
DOiT is supported by an extensive teacher manual with a login for extra materials provided at the DOiT website.
Students at control schools receive regular education (no treatment).
Primary outcome measure
The primary outcome is the dissemination process measured by teacher questionnaires, logbooks and interviews.
At baseline, 10 months and 20 months, all teachers involved in the implementation of DOiT are asked to complete an online questionnaire about the impeding and facilitating factors of the implementation of DOiT. The majority of the questionnaire consists of structured questions, measured on a bipolar five-point Likert scale. A few open-ended questions are added. The questionnaire is based on existing
questionnaires, used in the previous DOiT evaluation and the Krachtvoer evaluation study. The questionnaire contains questions regarding the context, recruitment, satisfaction, maintenance, and
potential relevant implementation-related determinants of the program. Additionally, the questionnaire contains items on other ongoing studies and other innovations or school health-promotion programs.
After each lesson teachers are requested to complete an online log. Completing the log takes approximately 5 minutes per lesson. Using this log, we aim to administer completeness of implementation by having teachers indicate if the lesson was taught, when it was taught and how the lesson was prepared and implemented. Teachers can tick off what activities were executed in preparation of the lesson on a list of proposed activities according to the teacher manual and how much time they spend on these activities. Teachers tick off what materials were used during the lesson, what lesson activities were implemented and if the implementation complied with the prescription in the teacher manual. Finally, teachers report how much time they spent in the classroom and rate their satisfaction with the lesson on a ten point rating scale.
At the end of each school year, i.e. in total two times during the research period, a sub-group of teachers and the coordinator are invited for an in-depth interview to gain more insight into the implementation of the DOiT program, its content, recruitment, fidelity and satisfaction with the dissemination strategy, and overall satisfaction with DOiT. Furthermore, facilitators and barriers for implementation, intentions and opportunities for future implementation of DOiT are discussed.
Secondary outcome measures
The secondary outcome is the effect of the program on the students' objectively measured body mass index, skinfold thickness and waist circumference and self-reported energy balance-related behaviours among students.
Before the start of DOiT and after 20 months, we measure body weight, body height, skinfold thickness, waist and hip circumference.
1. Body weight is measured and recorded within 0.1 kg with a calibrated electronic flat scale (Seca 888).
2. Body height is measured and recorded with an accuracy of 1 mm using a portable stadiometer.
3. Skinfold thickness (i.e. m.triceps, m.biceps, m.suprailiacalis, m.subscapularis) is measured on the left side of the body to the nearest 0.2 mm
4. Waist and hip ratio are measured with a Seca 206 waist circumference measure (Seca, Hamburg, Germany) to accuracy of 0.5 cm
Energy balance-related behaviours
Before the start of DOiT and after 20 months, students are asked to complete the DOiT questionnaire in a classroom. The DOiT questionnaire addresses the following EBRBs:
1. Consumption of sugar-sweetened beverages
2. Consumption of high sugar/high fat snacks
3. Physical activity (sports and active transport)
4. Screen time (TV viewing and computer use)
5. Breakfast behaviour
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
Participating schools need to meet the following criteria:
1. Willing to implement DOiT during 2 subsequent school years
2. A signed agreement of participation in the study during that period (2011-2013)
3. Willingness to appoint a DOiT coordinator who will be the linking agent between the research team and the school
4. Being able to participate with at least 3 classes of the first two years of their pre-vocational education
5. Willingness to provide space and time for measurements.
There are no individual inclusion criteria for study participation.
Target number of participants
640 students at the implementing schools and 640 students at the control schools
Participant exclusion criteria
Does not meet inclusion criteria
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
VUmc MS Center Amsterdam
SNS REAAL Fonds (Netherlands)
SNS REAAL Fonds (Netherlands) ref: 20109966
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
van Nassau F, Singh AS, van Mechelen W, Paulussen TG, Brug J, Chinapaw MJ, Exploring facilitating factors and barriers to the nationwide dissemination of a Dutch school-based obesity prevention program "DOiT": a study protocol., BMC Public Health, 2013, 13, 1201, doi: 10.1186/1471-2458-13-1201.
van Nassau F, Singh AS, Cerin E, Salmon J, van Mechelen W, Brug J, Chinapaw M, The Dutch Obesity Intervention in Teenagers (DOiT) cluster controlled implementation trial: intervention effects and mediators and moderators of adiposity and energy balance-related behaviours, Int J Behav Nutr Phys Act., 2014, 11, 1.
van Nassau F, Singh AS, van Mechelen W, Brug J, Chinapaw MJ, Body mass index, waist circumference and skin-fold thickness in 12- to 14-year-old Dutch adolescents: differences between 2003 and 2011, Pediatr Obes, 2014 , 9, 6, e137-e140, doi: 10.1111/ijpo.233.