Vaughn 2021.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 8‐10 months Unit of allocation: centre Unit of analysis: child
Participants	Service type: centre‐based Operation: not reported Country (region): USA (North Carolina) Country income classification: high Low‐SES sample: unclear Population description: Central North Carolina, including a mix of rural and suburban counties Inclusion criteria: centres having a 3–4‐year‐old classroom, having a 3–5‐star quality rating or being exempt from rating, providing lunch, not exclusively serving children with special needs Exclusion criteria: at least 7 parents had to sign consent for the centre to remain eligible. Number of services randomised: 92 (48 intervention, 44 control) Number of children randomised: 853 (446 intervention, 407 control) Characteristics Children Age: 47.93 months (SD 6.96) Gender (% female): 49.20% Ethnicity: white: 46.4%; black or African American: 36.3%; other: 17.4%; Latino ethnicity: 8.6% Parents Age (years): 33.46 (SD 7.82) Gender (% female): 85.30% Ethnicity: white: 53.3%; black or African American: 36.9%; other: 9.8% Latino ethnicity: 6.2% Parent/family SES: family income: under USD 30,000: 28.1%; USD 30,000‐USD 59,999: 18.3%; USD 60,000: 37.9%; Prefer not to answer: 15.7% Method of recruitment: community organisations shared information about the study with local centre directors and endorsed participation. Research staff followed‐up by phone to gauge initial interest and eligibility, and then in person to verify interest and obtain a Memorandum of Understanding. Information packets were shared with eligible classroom teachers (i.e. teachers of 3–4 year‐olds, able to write/speak English). At least 1 teacher had to sign consent for the centre to remain eligible. Research staff worked with participating teachers to distribute similar packets to eligible parents (i.e. parent of a 3–4 year old, able to write/speak English) and conduct in‐person visits to answer questions and collect written consent. At least 7 parents had to sign consent for the centre to remain eligible. Missing data/dropout: not reported Reasons for dropout: not reported Characteristics of dropouts: not reported
Interventions	Programme name: Healthy Me, Healthy We Number of conditions: 1 intervention, 1 control Intervention duration: 8 months Intervention setting: ECEC Intervention strategies: Health curriculum Children Education: as part of the kick‐off event, the classroom activity involved the Healthy Me, Healthy We theme song and dance. Plus, 4 x 6‐week units where teachers used activity cue cards to lead 8 classroom activities to build children’s knowledge and skills. Ethos and environment Children Resources: a welcome letter from Dr. Fitbodi (Healthy Me, Healthy We mascot) was added in wave 2 to help teachers introduce the campaign. ECEC staff Training: directors and teachers received 2 x training sessions (5 h total) to support centres’ ability to deliver the campaign. Support: 3 x informal check‐ins (< 1 h) by the study interventionist to deliver programme materials, offer technical assistance and inquire about event planning Resources: in wave 2, teachers received an outreach toolkit with resources to boost parent engagement (e.g. social media posts about classroom activities). Service Environment: hanging the Healthy Me, Healthy We centre banner and classroom posters (1 per classroom). Event: the campaign initiated with a kick‐off event and concluded with a celebration event (promoting the event to parents, displaying a certificate of completion, having teachers wear Healthy Me, Healthy We buttons, posting pictures of activities, having children perform the Healthy Me, Healthy We song, and awarding children Healthy Me, Healthy We ribbons). Partnerships Families Invitation: sending invitations to parents, signing the Fit Family Promise (at school and at home) Resources: teachers distributed Our Turn cards to prompt parents to do at‐home activities. Parents received a Family Guide magazine at the start of each unit that introduced unit goals, presented benefits of healthier behaviours, encouraged practices to support healthier behaviours, and offered at‐home activities. Parents received an activity tracker to log at‐home activities. Intensity of intervention: 4 x 6‐week units for children; 2 x teacher training sessions (3 h and 2 h); 3 x check‐ins (< 60 min); 1 conclusion event Intervention delivered by: research team, ECEC staff Modality: face‐to‐face, online, written Theoretical basis: development was guided by Social Marketing Approach and informed by the Social Ecological Framework, Exchange Theory, and Social Cognitive Theory Description of control: wait‐list control
Outcomes	Outcomes relating to child dietary intake: Diet quality (total) Number of participants analysed: Intervention baseline: 446 Intervention follow‐up: 446 Control baseline: 407 Control follow‐up: 407 Data collection measure: combination of observation (using the Diet Observation in Child Care protocol) and parent‐completed food diary Data collector: researchers and parent Validity of measures used: not reported Outcomes relating to child physical measures: BMI, BMI z‐score Number of participants analysed: Intervention baseline: 446 Intervention follow‐up: 446 Control baseline: 407 Control follow‐up: 407 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: funded by the National Heart, Lung and Blood Institute [R01HL120969]. Support was also received from the Center for Disease Control and Prevention [U48DP005017] and National Institute of Diabetes and Digestive and Kidney Diseases [P30DK056350].
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Centres were stratified by county, and the study statistician created randomisation tables using a permuted block approach (with blocks of 2 and 4). The project manager used these tables to assign centres to the intervention or control arm.
Allocation concealment (selection bias)	Low risk	Randomisation occurred on a rolling basis after baseline measures were collected and sufficient data had been confirmed (i.e. at least 7 children per centre with usable diet and physical activity data).
Blinding of participants and personnel (performance bias) Diet outcomes	Unclear risk	Only the study statistician, project manager, and those delivering the intervention knew allocation assignments. Investigators and data collectors remained blind to study allocation. Teachers were not blind to the treatment, and it is unclear whether the outcome could be influenced by lack of blinding.
Blinding of participants and personnel (performance bias) Physical outcomes	Low risk	Only the study statistician, project manager, and those delivering the intervention knew allocation assignments. Investigators and data collectors remained blind to study allocation. The outcome is not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Diet outcomes	Unclear risk	Parents recorded children's dietary intake in food diaries, and intake at child care was assessed by research staff using the Diet Observation in Child Care protocol. Parent‐reported outcome may be influenced by lack of blinding. Even though research staff were blinded to assignment, intervention posters were hung in the intervention classrooms and could have led to broken blinding for observers.
Blinding of outcome assessment (detection bias) Physical outcomes	Low risk	Children's height, weight, and waist circumference were measured by research staff who were blinded to group assignment.
Incomplete outcome data (attrition bias) Diet outcomes	Unclear risk	Study authors stated that "Hypotheses were tested under the intent‐to‐treat (ITT) principle using Generalized Linear Mixed Models (GLMM)." However, information on missing data is not reported. Risk of attrition bias is unclear.
Incomplete outcome data (attrition bias) Physical outcomes	Unclear risk	Study authors stated that "Hypotheses were tested under the intent‐to‐treat (ITT) principle using Generalized Linear Mixed Models (GLMM)." However, information on missing data is not reported. Risk of attrition bias is unclear.
Selective reporting (reporting bias)	Unclear risk	Waist circumference mentioned in protocol and methods of study, but findings not reported
Recruitment bias	Low risk	Randomisation occurred on a rolling basis once baseline measures were collected and sufficient data had been confirmed (i.e. at least 7 children/centre with usable diet and physical activity data).
Baseline imbalance	Low risk	There were slight differences between arms in terms of children’s Latino ethnicity (P = 0.02), family income (P = 0.03), and parents’ marital status (P = 0.04). These variables were incorporated as covariates in fully adjusted models.
Loss of clusters	Unclear risk	Not sufficiently reported
Incorrect analysis	Low risk	Study authors stated that "Hypotheses were tested under the intent‐to‐treat (ITT) principle using Generalized Linear Mixed Models (GLMM) that accounted for the correlation induced by the clustering of children within the childcare centres. Models did not account for clustering of children within classrooms as it is common for children to move between classrooms; hence, this level of clustering was not tracked."
Contamination	Unclear risk	No evidence to make assessment
Other bias	Low risk	No clear other source of bias