Long-term process evaluation of a school-based programme for overweight prevention

The epidemic increase in childhood overweight demands effective and also feasible prevention programmes. A school-based environmental and educational intervention focusing on the promotion of water consumption was found to be effective for overweight prevention in children. Process evaluation and long-term surveillance are necessary to evaluate the feasibility and sustainability of the intervention programme in a school setting.

Process evaluation was conducted during the intervention period (one school year) and a 19-month follow-up after the intervention trial on the prevention of overweight in 17 elementary schools. Data were collected through measuring the water flow of water fountains installed in schools, and questionnaires and interviews were administered to teachers and headmasters of intervention schools. Main outcomes were implementation of the intervention components, behavioural modification of the children concerning water consumption, and teacher and headmaster attitudes towards the intervention.

Eleven out of 17 intervention schools maintained the water fountains until 19-month follow-up. The mean water flow of the fountains decreased initially, but remained stable after the during the follow-up period. The implementation rate of the educational units by teachers varied between the units from 13% to 84%. Teachers graded the overall concept of the intervention as good, continuously during the intervention and follow-up period. The majority of teachers organized the water supply of the fountains on the class level during the intervention period but not during the follow-up.

The long-term process evaluation showed that the combined educational and environmental intervention has potential for sustained modifications in the beverage consumption habits of children. It also identified barriers and promoting factors of a sustainable and feasible implementation of the preventive programme in a school setting.