Background: The evidence-based Dutch Obesity Intervention in Teenagers (DOiT) program is a school-based obesity prevention program for 12 to 14-year olds attending the first two years of prevocational education. This paper describes the study protocol applied to evaluate (a) the nationwide dissemination process of DOiT in the Netherlands, and (b) the relationship between quality of implementation and effectiveness during nationwide dissemination of the program in the Netherlands.
Methods: In order to explore facilitating factors and barriers for dissemination of DOiT, we monitored the process of adoption, implementation and continuation of the DOiT program among 20 prevocational schools in the Netherlands. The study was an observational study using qualitative (i.e. semi-structured interviews) and quantitative methods (i.e. questionnaires and logbooks). Eight process indicators were assessed: recruitment, context, reach, dosage, fidelity, satisfaction, effectiveness and continuation. All teachers, students and parents involved in the implementation of the program were invited to participate in the study. As part of the process evaluation, a cluster-controlled trial with ten control schools was conducted to evaluate the effectiveness of the program on students' anthropometry and energy balance-related behaviours and its association with quality of implementation.
Discussion: The identified impeding and facilitating factors will contribute to an adjusted strategy promoting adoption, implementation and continuation of the DOiT program to ensure optimal use and, thereby, prevention of obesity in Dutch adolescents.
Trial registration: Current Controlled Trials ISRCTN92755979.