“My Life – I Decide” Study Protocol: A health-promoting school intervention to foster well-being, physical- and mental health among 10th grade students in Denmark

Abstract
Background: Strategies to improve mental health and well-being of young people are needed, as poor mental health and well-being increase young people’s risk of not completing secondary education. A multicomponent health-promoting school intervention, “My life – I decide” (hereafter My life), was developed with the aim to foster well-being, physical- and mental health among students in secondary education (10th grade, age 15-16 years) in Denmark. The intervention seeks to achieve this by promoting a) young people’s social and emotional skills and health literacy, and b) a healthy class and school environment. The objective of this paper is to describe the theoretical foundation, the intervention and study design, and evaluation methods of My Life.
Method: The intervention builds upon the health-promoting school approach, life-skills, action learning and education outside the classroom. The settings are the school and the local community. A core element in the delivery and implementation of the intervention is establishing a collaboration between the municipal health department, the schools, and local community actors to ensure a holistic and community-oriented approach. The intervention consists of a 12-week educational program run by municipal health consultants together with the schoolteachers followed by systems-oriented processes to implement further health promotion actions at the school and local community levels. The study design is a pragmatic, controlled waiting-list design, with four schools implementing the intervention during the school year 2025/26, and four control schools implementing the intervention during 2026/27. Schools were matched based on the number of students, contextual and sociodemographic factors, and readiness to implement the intervention. Approximately 500 students across 28 classes have signed up for the study. Student outcomes will be assessed at three points using electronic questionnaires: (1) before educational program begins (baseline), (2) immediately after the educational program is implemented (follow-up 1), and (3) approximately 5 months later (follow-up 2). A qualitative designed process evaluation using focus groups, interviews, and participatory observation will investigate implementation, mechanisms, and context, guided by the programme theory developed from evidence and pilot-testing.
Discussion: The My Life study is expected to significantly contribute to the field of health promotion in secondary education. Evidence on the effectiveness and feasibility is provided of this multicomponent health-promoting school intervention targeting secondary education teachers, school management, school local actors, and municipality health administrations. The evaluation will synthesize the evidence and evaluate if the comprehensive intervention can be recommended for implementation at scale.

Dissemination and Impact
The results will be shared through peer-reviewed publications and presentations at national and international conferences. Additionally, public engagement efforts, such as op-eds and media outreach, will foster debate on initiatives to strengthen young people's mental health and well-being. The intervention manual, developed for municipal health consultants and teachers, will be made freely available and provide detailed guidance on implementing the program. This practical tool ensures that My Life can be replicated and adopted to other educational contexts ensuring scalability.