Implementation and systems impact of a systems-based health promotion programme at Danish vocational schools: results after 2-years follow-up

Background Vocational schools are important settings for health promotion among young people from lower socioeconomic backgrounds, who are at an increased risk of engaging in health-compromising behaviours. However, health promotion interventions are rarely sustained in such settings. Systems approaches have been proposed as a promising approach to health promotion but remain unexplored in vocational school settings in Denmark. This study aimed to examine the implementation and systems impact of a systems approach to health promotion in Danish vocational schools and to elucidate the overarching pathways through which such impacts may emerge.Methods This longitudinal qualitative study was conducted as part of the Data Health programme, a systems-based initiative implemented across eight Danish vocational schools and four municipalities. Quarterly interviews with school coordinators or department managers (n = 59) were analysed using principles from Ripple Effect Mapping to visualise evolving actions and perceived impacts over a two-year period and identify enablers and barriers to systems impact. A cross-case analysis was used to identify plausible pathways enabling perceived systems impact.Results At two-year follow-up, 42 actions had been implemented, and systems impact (structural, relational, and/or transformative change) was perceived to have occurred at six out of eight schools. Two reinforcing systems impact pathways emerged: (1) internally driven change via committed staff and distributed leadership, and (2) externally supported change through collaboration with community actors. Key enablers included dedicated change agents, financial resources, student participation, external networks, and backbone support. Barriers included staff turnover, time constraints, and students alternating between school and workplace-based training.Conclusions These findings provide valuable insights for the future adaptation of the Data Health programme and for informing broader systems-based strategies in vocational school settings.Trial registration Registered in ClinicalTrials.gov: NCT05308459, retrospectively registered on 4th April 2022.