The Healthy School Start Plus Intervention for Prevention of Childhood Overweight and Obesity in Disadvantaged Areas Through Parental Support in the School Setting - a Parallel Group Cluster Randomised Trial

The proposed study is a cluster randomized trial to test the effectiveness of a parental support programme in pre-school class to promote healthy dietary habits and physical activity and prevent obesity, delivered by teachers and school health services and in collaboration with primary care. The control condition is standard care in schools. The 6-month programme is carried out in schools in disadvantaged areas and is universal. It is based on Social Cognitive Theory and consists of four components: 1) Health information to parents regarding the child; 2) Motivational Interviewing with the parents by the school nurse concerning the child; 3) classroom activities for the children with home assignments; and 4) a web-based self-test of type-2 diabetes risk by parents, with follow-up in primary health care. The primary outcome is assessed as the difference between the intervention and the control group directly after the end of intervention at 6-months post baseline, and at follow-up 18 months post baseline, adjusted for baseline values. The outcome variables are the intake of unhealthy foods, unhealthy drinks, and healthy foods assessed by a newly developed method using photo-based dietary assessment. The secondary outcomes are physical activity and time spent sedentary measured by accelerometry, and measured BMI and waist circumference. Hypothetical mediator variables are parental self-efficacy and parenting practices regarding diet and physical activity assessed by questionnaire. Process evaluation will be performed through interviews and questionnaires to study how well the programme was implemented in terms of dose, fidelity, acceptability and feasibility. The programme is in line with the latest evidence regarding the prevention of childhood obesity: that schools should be a focal point of prevention efforts, interventions should involve multiple components, and include the home environment. If effective, it will fill a large knowledge gap concerning evidence-based health promotion practice within school health services to prevent overweight and obesity and in the long term reduce social inequalities in health.