Fitzgibbon 2011.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 14 weeks (varies with outcomes) Unit of allocation: school Unit of analysis: child
Participants	Service type: centre‐based (Head Start) Operation: public Country (region): USA (Chicago) Country income classification: high Low‐SES sample: yes Population description: not reported Inclusion criteria: up to 2 children/family were eligible to participate. Exclusion criteria: not reported (exclusions appear to occur after baseline) Number of services randomised: 18 (9 intervention, 9 control) Number of children randomised: 729 (376 intervention, 353 control) Characteristics Children Age: 51.3 months (SD 6.6) Gender (% female): 53% Ethnicity: black: 94%; Latino: 3%; multiracial/other: 3% Parents Age (years): 30.9 (SD 8.6) Gender (% female): 90% Ethnicity: not reported Parent/family SES: Income, USD, median: 15,000 Education, years: 12.3 (SD 1.7) Method of recruitment: not reported Missing data/dropout: baseline data were collected for the 669 children (92%) however, 50 of these children were excluded. Reasons for dropout: transferred out of the participating schools before the intervention began, and 1 child was excluded because he was the 3rd child in a participating family. Characteristics of dropouts: not reported
Interventions	Programme name: teacher‐delivered Hip‐Hop to Health Jr Number of conditions: 1 intervention, 1 control Intervention duration: 14 weeks Intervention setting: ECEC and home Intervention strategies: Health curriculum Children Education: teachers taught 2 sessions/week, with the option of including a 3rd session. Each week focused on a theme with a specific objective. Each session included a 20‐min lesson related to healthy eating and exercise. Lessons featured colourful "pyramid puppets" to represent the 7 food groups of the food pyramid. Intervention incorporated songs and raps on a CD. Ethos and environment Children Exposure: each session also incorporated 20 min of physical activity. Intervention CD included 2 fully scripted exercise routines. ECEC staff Training: teachers attended training sessions. Following the first formal session, the intervention co‐ordinator conducted 3 in‐school training sessions and met with teachers on an individual basis weekly. All participants Cultural: cultural considerations for black children were incorporated in the intervention. Partnerships Families Resources: parents received weekly newsletters that paralleled the children's curriculum in content and included a homework assignment. Parents also received the CD to reinforce nutrition and physical activity concepts at home. Incentive: parent received USD 5 for each homework assignment completed and returned. Intensity of intervention: 1 x 3 h initial staff training, plus 3 x in‐school staff training sessions; intervention co‐ordinator met with teachers weekly to support intervention delivery; 40‐min lessons, 2 sessions/week (teacher could opt for 3rd); weekly parent newsletters that included homework Intervention delivered by: research team, ECEC staff Modality: face‐to‐face, written Theoretical basis: Social Cognitive Theory and Self Determination Theory Description of control: alternative intervention control (covered health concepts including care seats, seat belt safety, immunisation, dental health and calling 911)
Outcomes	Outcomes relating to child dietary intake: Energy, total fat, fibre, fruit, 100% fruit juice, vegetables, diet quality (total, total fruit, whole fruit, saturated fat, whole grains, total vegetables, solid fats and added sugars) Number of participants analysed: Intervention baseline: 278 Intervention follow‐up: 196‐238 Control baseline: 230 Control follow‐up: 160‐202 Data collection measure: 24‐h diet record (combination of in‐school observations and food records or recalls completed by parent) Data collector: parent and researcher Validity of measures used: not reported Outcomes relating to child physical measures: BMI, BMI z‐score, weight Number of participants analysed: Intervention baseline: 325 Intervention follow‐up: 309 Control baseline: 293 Control follow‐up: 280 Data collection measure: objectively measured (CDC) Data collector: researcher Validity of measures used: not reported Outcome relating to child language and cognitive performance: not reported Outcome relating to child social/emotional measures: not reported Outcome relating to child quality of life: not reported Outcome relating to cost: not reported Outcome relating to adverse consequences: not reported
Notes	Funding source: supported by the National Heart, Lung and Blood Institute (HL081645)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The random sequence generation procedure was unclear.
Allocation concealment (selection bias)	Unclear risk	No information on the method of allocation concealment reported.
Blinding of participants and personnel (performance bias) Diet outcomes	High risk	Due to the nature of the study design, both parents and interviewers were aware of group assignments. The outcome is likely to be influenced by lack of blinding.
Blinding of participants and personnel (performance bias) Physical outcomes	Low risk	Due to the nature of the study design, both parents and interviewers were aware of group assignments. However, the outcome is not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Diet outcomes	High risk	Dietary intake was reported by parents and observed by research staff. There was no blinding of outcome assessors, and the outcome measurement is likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Physical outcomes	Low risk	Children's height and weight were measured by interviewers aware of group assignments, however the outcome measurements are not likely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) Diet outcomes	Low risk	Only 86% of intervention and 79% of control had baseline diet data, and follow‐up loss was 14% of intervention children with baseline diet data (27% loss from all children in intervention group) and 12% of control children with baseline diet data (31% loss from all children in control group). Study authors stated that "The proportion of children with valid records differed by school (highest = 94%, lowest = 55%, p< 0.001) but not by intervention group (P = 0.24). The 440 children who had valid diet records at both visits did not differ significantly from the other 178 children in gender, race, age, BMI, BMI z‐score, weight or height. There was also no significant difference in parents' gender, age, education, median income, marital status, full‐time employment, BMI, height, or weight." Study authors stated that "Only children with valid data for the relevant variables at baseline and postintervention were included in analyses (BMI change, physical activity, screen time, and diet)." Therefore, risk of attrition bias was considered low.
Incomplete outcome data (attrition bias) Physical outcomes	Low risk	All children enrolled in the study (minus those who were excluded prior to intervention) were measured at baseline. Follow‐up data were available for 309 (95%) children in the intervention group and 280 (96%) children in the control group. No information regarding missing data provided. Study authors stated that "Only children with valid data for the relevant variables at baseline and postintervention were included in analyses (BMI change, physical activity, screen time, and diet)." Therefore, risk of attrition bias was considered low.
Selective reporting (reporting bias)	Unclear risk	No prospective trial protocol or trial registration so it was unclear whether there was selective outcome reporting.
Recruitment bias	Unclear risk	Recruitment of preschools occurred before randomisation, however it is not clear whether recruitment of children came before or after randomisation of preschools.
Baseline imbalance	High risk	Groups differed at baseline by total screen time/d, energy intake, and fibre intake, however the model only adjusted for baseline BMI and BMI z‐score, age, preschool, and classroom.
Loss of clusters	Unclear risk	One cluster did not have diet observation data because school personnel felt the in‐school diet observations would be disruptive. It is unclear whether other clusters were lost due to insufficient reporting.
Incorrect analysis	Low risk	Study authors stated that "To test for differences between groups in BMI and BMI Z score change at postintervention, we used both mixed‐model analysis of variance, controlling for school and classroom nested within school, and mixed model analysis of covariance, controlling for school, classroom nested within school, the baseline value, and baseline age."
Contamination	Unclear risk	No evidence to make assessment
Other bias	Low risk	No clear other source of bias