Let's Nudge: Pilot randomised trial for a nudge-based obesity intervention in the home for children presenting to paediatricians

INTERVENTION: Standardised paediatrician care and in‐home nudge modifications (intervention group): Standardised paediatrician care will be delivered by community‐based general paediatricians trained in the assessment of obesity for the study. Parent(s) and the child will attend a single 45‐minute consultation at the child’s usual paediatric practice. The consultation will provide: (1) brief clinical assessment of weight‐related health (usually to confirm simple obesity without unusual causes or comorbidities requiring medical management); (2) effective communication about obesity using simple tools understood by families; and (3) additional testing, treatment or referral to a specialist tertiary weight management clinic for the few cases for whom these would be clearly indicated. There will be no cost to families for this consultation. Though unlikely, families will be free to schedule further weight management appointments at the paediatricians' discretion without the involvement of the research team. The in‐home nudge modifications will be delivered in person by a trained research assistant over two home visits. The first visit will assess the home environment and implement the nudges (90 minutes, two researchers), the second (one month later) will refine the nudges (30 minutes, one researcher). Phone support with a trained research assistant will be available for the duration of the intervention. A ‘nudge’ is any aspect of the decision‐making environment that encourages choices that individuals recognise are good for them but which they may nevertheless struggle to make (eg whether or not to have that second slice of cake). It does not restrict their options. In the context of obesity, nudges are about making healthy choices easier. The nudges used in this study are derived from existing methods that have shown some promise in the promotion of health behaviour. Examples include (but are not limited to) smaller tableware to limit overconsumption, cutlery designed to slow eating rate and enhance internal satiety cues, school lunchboxes with compartments specified for healthy foods, and fruit bowls to make healthy foods visible and easily accessible, while less healthy alternatives are out of sight and less easily accessed. CONDITION: Childhood obesity PRIMARY OUTCOME: Acceptability assessed using study‐designed questions with parent and paediatrician report. Feasibility assessed using study‐designed questions with parent and paediatrician report. INCLUSION CRITERIA: Children presenting to the participating paediatric practice or children whose parents initiated contact with us about the study who are aged between 3–12 years old (up to but not including their 13th birthday) and identified as obese according to CDC charts (ie BMI greater than or equal to the 95th age‐ and sex‐specific percentile), and their families. At home visits, the research assistant will recommend a suite of nudges to each family based on (a) their questionnaire information and (b) their home environment. Families will choose which nudges they feel able to implement based on their own situation. As each nudge could have at most a small impact in and of itself, and nudges are expected to be additive, we will encourage families to choose as many suitable nudges as possible. Families will be asked to maintain the nudges for the duration of the trial. Self‐reported adherence will be assessed using study‐designed questions in the follow‐up survey, and we will record whether implemented nudges have been sustained at home visit 2 and the three‐month follow up visit. Encouragement will be given at the home visits and in any family‐initiated telephone support to improve fidelity. SECONDARY OUTCOME: Blood pressure assessed using digital blood pressure device. Body fat percentage assessed using bioelectrical impedance analysis digital scales. Body Mass Index (BMI) z‐score calculated using age and sex‐specific United States Centers for Disease Control (CDC) growth charts. Height assessed using a portable rigid stadiometer. Weight assessed using bioelectrical impedance analysis digital scales. Health‐related quality of life assessed using the Pediatric Quality of Life Inventory (PedsQL) 4.0 with parent‐proxy report for all ages and child self‐report for 5‐11 year olds. Obesogenic home environment assessed using the Family Nutrition and Physical Activity (FNPA) screening tool with parent report. Parent mental health assessed using the Kessler‐6 (K6). Parent‐reported child dietary intake assessed using the ASA24 for families in the intervention and control group. Physical activity and sedentary behaviour assessed using a digital accelerometer worn on the wrist for 7 full days. This will measure mean activity counts per minute as well as the percentage of time spent in sedentary, light, moderate and vigorous activity. Self‐reported child body satisfaction assessed using the Children's Body Image Scale (CBIS) for 8‐11 year olds. Self‐reported child physical appearance and self worth assessed using a modified version of Harter's Perceived Competence Scale for 5‐11 year olds. Study‐designed questions assessing help‐seeking to manage child's weight, child activity levels and a range of potential confounders with parent report. Study‐designed questions assessing paediatrician competence and confidence to assess childhood obesity and related comorbidities. Waist circumference assessed using steel pocket tape measure.