Kids FIRST: Development and Feasibility of a Family-based Intervention to Reduce Snacking and Screen Time in Children

The Kids FIRST intervention was performed and reported in accordance with the Consolidated Standards of Reporting Trials extension to randomised pilot and feasibility trials guidelines. The study was approved by the Ethical Advisory Committee of Loughborough University (R15-PO36).

Setting and recruitment Kids FIRST was family based with a school component. The study targeted families with at least one 9-11 year old child. Families were recruited through schools in the East Midlands region of the United Kingdom between September and December 2015. Twenty-five primary schools were selected from a database of schools and school contacts. Headteachers were sent study information via email, which was followed-up with a telephone call, inviting them to be part of the project. In participating schools, parents/caregivers of children aged 9-11 years (year 5 and 6 of Primary School) were sent information sheets via the school outlining the study details and inviting them and their child to participate.

Study design The study was a pilot four-arm cluster randomised controlled trial with assessments at pre- (baseline) and post-intervention (13 weeks after baseline). The study arms were three intervention groups and a control group. The intervention groups were: Group 1: targeting reductions in screen-time and unhealthy snacking (ST+Sn), Group 2: targeting reductions in screen-time (ST), and Group 3: targeting reductions in unhealthy snacking (Sn). Following consent by headteachers, schools were randomised to either one of the three intervention groups or the control group by NP using computer generated random sequences. Only NP had access to the randomisation sequences (which were on a password protected file). This method of randomisation eliminated the possibility of contamination between pupils and parents from the same school.

Theoretical underpinning of the Kids FIRST intervention The Kids FIRST intervention was framed in a social ecological perspective, and was theoretically informed, drawing on constructs designed to address potential individual, behavioural, social and physical home environmental mediators derived from Habit Theory, Behavioural Choice, and Social Cognitive theories of individual behaviour change.

The taxonomy of behaviour change techniques was applied to characterise the association between the potential mediators targeted in the Kids FIRST study, the intervention components / strategies developed, and the theoretical underpinning. Supplementary Table 1 describes the specific behaviours that were targeted by the intervention and the practical application of the behaviour change techniques applied in relation to the Kids FIRST intervention.