A healthy school start - parental support to promote healthy dietary habits and physical activity in children: design and evaluation of a cluster-randomised intervention.

Background: Childhood obesity is multi-factorial and determined to a large extent by dietary habits, physical activity and sedentary behaviours. Previous research has shown that school-based programmes are effective but that their effectiveness can be improved by including a parental component. At present, there is a lack of effective parental support programmes for improvement of diet and physical activity and prevention of obesity in children.

Methods/design: This paper describes the rationale and design of a parental support programme to promote healthy dietary habits and physical activity in six-year-old children starting school. The study is performed in close collaboration with the school health care and is designed as a cluster-randomised controlled trial with a mixed methods approach. In total, 14 pre-school classes are included from a municipality in Stockholm county where there is large variation in socio-economic status between the families. The school classes are randomised to intervention (n = 7) and control (n = 7) groups including a total of 242 children. The intervention is based on social cognitive theory and consists of three main components: 1) a health information brochure; 2) two motivational interviewing sessions with the parents; and 3) teacher-led classroom activities with the children. The primary outcomes are physical activity in the children measured objectively by accelerometry, children's dietary and physical activity habits measured with a parent-proxy questionnaire and parents' self-efficacy measured by a questionnaire. Secondary outcomes are height, weight and waist circumference in the children. The duration of the intervention is six months and includes baseline, post intervention and six months follow-up measurements. Linear and logistic regression models will be used to analyse differences between intervention and control groups in the outcome variables. Mediator and moderator analysis will be performed. Participants will be interviewed.

Discussion: The results from this study will show if it is possible to promote a healthy lifestyle and a normal weight development among children from low-income districts with relatively limited efforts involving parents. Hopefully the study will provide new insights to the further development of effective programmes to prevent overweight and obesity in children.

Trial Registration: ISRCTN: ISRCTN32750699.