Lumeng 2017.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 6 months Unit of allocation: classrooms Unit of analysis: child
Participants	Service type: centre‐based (Head Start) Operation: federally‐funded Country (region): USA (Michigan) Country income classification: high Low‐SES sample: yes Population description: urban and rural Inclusion criteria: inclusion criteria are that the child is aged 3 or 4 years at study enrolment. Exclusion criteria: exclusions were significant developmental disabilities that would preclude participation, child is a foster child, or parent is non‐English speaking. Number of services randomised: 3 Head Start agencies, 18 classrooms (6 Intervention 1; 6 Intervention 2; 6 control) Number of children randomised: 697 (224 Intervention 1; 255 Intervention 2; 218 control) Characteristics Children Age: Intervention 1: 4.10 years (SD 0.52) Intervention 2: 4.12 years (SD 0.52) Control: 4.12 (SD 0.53) Gender (% female): Intervention 1: 49.1% Intervention 2: 51.4% Control: 53.7%; Ethnicity: Intervention 1: white, non‐Hispanic: 35.9%; African American, non‐Hispanic: 39%; Hispanic/other: 25.1% Intervention 2: white, non‐Hispanic: 56.4%; African American, non‐Hispanic: 27%; Hispanic/other: 16.7% Control: white, non‐Hispanic: 52.1%; Hispanic/other: 24.9% Parents Age (years): Intervention 1: 29.8 (SD 6.8) Intervention 2: 29.6 (SD 6.7) Control: 29.2 (SD 12.2) Gender (% female): not reported Ethnicity: Intervention 1: white: 46%; African American, non‐Hispanic: 38.7%; Hispanic or other: 15.3% Intervention 2: white: 63.1%; African American, non‐Hispanic: 26.7%; Hispanic or other: 10.2% Control: white: 63.6%; African American, non‐Hispanic: 23%; Hispanic or other: 13.4% Parent/family SES: Family income‐to‐needs ratio Intervention 1: 0.84 (SD 0.53) Intervention 2: 0.84 (SD 0.56) Control: 0.88 (SD 0.53) Caregiver education Intervention 1: < high school: 17.1%; high school diploma or GED: 32.4%; some college courses but no degree: 40.1%; 2‐year college degree: 6.3%; ≥ 4‐year college degree: 4.1% Intervention 2: < high school: 14.7%; high school diploma or GED: 31%; some college courses but no degree: 39.3%; 2‐year college degree: 11.1%; ≥ 4‐year college degree: 4% Control: < high school: 14.3%; high school diploma or GED: 35.5%; some college courses but no degree: 33.6%; 2‐year college degree: 12.9%; ≥ 4‐year college degree: 3.7% Method of recruitment: families were told about the study during classroom open houses and through flyers in children’s backpacks, and compensated for returning an initial enrolment packet, including a signed written informed consent form. They were then contacted by telephone to review eligibility criteria that they reported in the enrolment packet and to confirm complete understanding of the study and validate informed consent. Missing data/dropout: Intervention 1: 21 lost to follow‐up, 2 discontinued intervention; Intervention 2: 18 lost to follow‐up, 2 discontinued intervention, 1 no longer eligible; Control: 11 lost to follow‐up, 3 discontinued intervention, 1 was no longer eligible Reasons for dropout: Intervention 1: 21 lost to follow‐up, 2 discontinued intervention; Intervention 2: 18 lost to follow‐up, 2 discontinued intervention, 1 no longer eligible; Control: 11 lost to follow‐up, 3 discontinued intervention, 1 was no longer eligible Characteristics of dropouts: not reported
Interventions	1Programme name: The Growing Healthy Study‍ Number of conditions: 2 interventions, 1 control Intervention duration: 4 x 1 school year Intervention setting: ECEC and home Intervention strategies: Intervention 1: Preschool Obesity Prevention Series (POPS) Health curriculum Children Education: 6 lessons delivered over 12 weeks by the Head Start teacher and Extension Educators (trained master's level nutrition educator), using children's stories with embedded obesity prevention themes related to behavioural goals (e.g. more fruit and vegetable consumption; less screen time) Ethos and environment Children Exposure: activities include classroom cooking experiences, games/activities associated with story themes, and goal setting. ECEC staff Training: training for Head Start. Training covers curriculum specifics as well as strategies for promoting parent self‐efficacy for behaviour change and importance of fidelity. Booster: booster training was provided each year. Support: phone support from trainers was available as needed. Partnerships Families Education: 8 x 75‐min lessons to develop and practice skills and a discussion of strategies to overcome challenges and problem‐solving techniques, with an emphasis on building knowledge and self‐efficacy about preventing childhood obesity. Recipes are included in each lesson. Exposure: hands‐on activities are included in each lesson. Support: reinforcing telephone contacts after every other lesson. 'Family Links' and 'Parent Pages' are sent home to reinforce content from school to home. Transportation and child care provided for parents to attend activities, as needed. Healthcare Delivery: a trained Master's‐level nutrition educator delivered parent education. Training: nutrition educators received 2‐d training (with booster sessions each year). Support: phone support from trainers was also available as needed. Intervention 2: POPS + Incredible Years Series (IYS) Health curriculum Children Education: 6 lessons delivered over 12 weeks by the Head Start teacher and Extension Educators, using children's stories with embedded obesity prevention themes related to behavioural goals (e.g. more fruit and vegetable consumption; less screen time). 60 x 15–20 min lessons delivered throughout the year during "Circle Time" in Head Start classrooms, followed by small group activities. Lessons address self‐regulation skills, problem solving strategies, and prosocial behaviour, and use child‐size puppets to teach skills and engage children. IYS child lessons were delivered by Master’s‐level mental health specialists, and Head Start teachers direct small group activities after each lesson. Ethos and environment Children Exposure: activities include classroom cooking experiences, games/activities associated with story themes, and goal setting. ECEC staff Training: training for Head Start. Training covers curriculum specifics as well as strategies for promoting parent self‐efficacy for behaviour change and importance of fidelity. Teachers also received training in classroom management strategies (e.g. handling transitions effectively) and were mentored by Master’s‐level mental health specialists in delivering IYS‐Child, so that delivery can slowly progress from delivery by mental health specialist, to co‐delivery by mental health specialist and teacher, to sole delivery by the teacher over time. Booster: booster training was provided each year. Support: phone support from trainers was also available as needed. Partnerships Families Education: 8 x 75‐min lessons to develop and practice skills and a discussion of strategies to overcome challenges and problem‐solving techniques, with an emphasis on building knowledge and self‐efficacy about preventing childhood obesity. Recipes are included in each lesson. 12–14 x 2‐h lessons focusing on parenting skills such as using effective praise, incentives, limit‐setting, and handling misbehaviour. Concepts are discussed using video vignettes about parenting challenges. Exposure: hands‐on activities are included in each lesson. Materials: homework Support: follow‐up phone calls. "Family Links" and "Parent Pages" are sent home to reinforce content from school to home. Transportation and child care provided for parents to attend activities, as needed. Healthcare Delivery: a trained Master's‐level nutrition educator delivered parent education. Training: nutrition educators received 2‐d training. The Master's‐level trained mental health specialists received training in classroom management strategies (e.g. handling transitions effectively). Booster: booster training was provided each year. Support: phone support from trainers was also available as needed. Master's level trained mental health specialists communicated extensively to share ideas and co‐ordinate efforts across sites, and received monthly supervision from IYS trainers about their delivery of IYS components, and consultation as needed. Master's‐trained mental health specialists also worked with teachers within their own site to develop lesson plans and small group activities. Intensity of intervention: Intervention 1: 8 x 75‐min weekly parent lessons with telephone follow‐ups every other lesson; 6 lessons for children over 12 weeks; 2 h of training for Head Start teachers; phone support as needed; 2 d of training for Extension educator Intervention 2: 8 x 75‐min weekly parents lessons with telephone follow‐ups every other lesson; 6 x 15‐20‐min lessons for children followed by small group activities; 2 h of training for Head Start teachers and phone support as needed; 2 h/week parent lessons with homework and follow‐up calls; 2 d of training for Extension educator Intervention delivered by: Intervention 1: research team, ECEC staff, healthcare staff Intervention 2: research team, ECEC staff, healthcare staff Modality: Intervention 1: face‐to‐face, telephone, written Intervention 2: face‐to‐face, telephone, written Theoretical basis: POPS is based on social cognitive theory Description of control: usual Head Start curriculum and support
Outcomes	Outcomes relating to child dietary intake: Vegetable intake, 100% fruit juice intake, sugar‐sweetened beverages intake, whole fruit intake Number of participants analysed: Intervention 1 baseline: 224 Intervention 1 follow‐up: 224 Intervention 2 baseline: 255 Intervention 2 follow‐up: 255 Control baseline: 218 Control follow‐up: 218 Data collection measure: 24 h diet recalls and observation Data collector: parent and researcher Validity of measures used: not reported Outcomes relating to child physical measures: Overweight, obese, normal weight, underweight, BMI z‐score Number of participants analysed: Intervention 1 baseline: 84‐220 Intervention 1 follow‐up: 82‐195 Intervention 2 baseline: 82‐250 Intervention 2 follow‐up: 82‐230 Control baseline: 68‐213 Control follow‐up: 68‐200 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: USDA/National Institute of Food and Agriculture/Agriculture and Food Research Initiative grant 2011‐68001‐30089
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Study authors stated that "The 6 teaching teams (hereafter referred to as “classrooms”) within each agency were randomly assigned by using an automated system overseen by the study statistician to 1 of 3 study arms, with the limitation that each agency have 2 classrooms allocated per study arm and that the classrooms were located in different communities to prevent cross contamination."
Allocation concealment (selection bias)	Unclear risk	Centres appear to be randomised prior to data collection, however it is unclear if families could potentially know allocation prior to recruitment. Study authors stated that "Families were assigned to a study arm as a function of their classroom assignment, which was based on the location geographically closest to their home address."
Blinding of participants and personnel (performance bias) Diet outcomes	Unclear risk	We assumed that due to the nature of the intervention, ECEC service staff and study personnel delivering the intervention were aware of their study allocation (intervention or control). However, the protocol states that "Only one classroom participates per physical school site to prevent cross‐contamination across study arms and ensure that participants are blind to group assignments." It is unclear whether the blinding of participants could have been broken or whether the lack of blinding would affect the outcome.
Blinding of participants and personnel (performance bias) Physical outcomes	Low risk	Although protocol states that "Only one classroom participates per physical school site to prevent cross‐contamination across study arms and ensure that participants are blind to group assignments," we assumed that due to the nature of the intervention, ECEC service staff, study personnel delivering the intervention, and parents were aware of their study allocation (intervention or control). However, the outcome is not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Diet outcomes	Unclear risk	Parents reported children's dietary intake via multiple 24‐h recalls conducted by trained dietitians who were blinded to study arm. Although protocol states that "Only one classroom participates per physical school site to prevent cross‐contamination across study arms and ensure that participants are blind to group assignments," due to the nature of the intervention, parents may have been aware that they were assigned to an intervention. The outcome measurement is likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Physical outcomes	Low risk	Study authors stated that "Data collectors and interventionists did not interact, and data collectors were blinded to study arm."
Incomplete outcome data (attrition bias) Diet outcomes	Low risk	Follow‐up data were available for 201 (90%) children in the Head Start (HS) + POPS group, 234 (92%) children in the HS + POPS + IYS group, and 203 (93%) children in the HS only (control) group. < 20% of participants dropped out with similar numbers across groups. ITT analyses were also used also. Therefore, risk of attrition bias was considered to be low.
Incomplete outcome data (attrition bias) Physical outcomes	Low risk	Follow‐up data were available for 201 (90%) children in the HS + POPS group, 234 (92%) children in the HS + POPS + IYS group, and 203 (93%) children in the HS only (control) group. < 20% of participants dropped out with similar numbers across groups. ITT analyses were also used also. Therefore, risk of attrition bias was considered to be low.
Selective reporting (reporting bias)	Unclear risk	Study authors stated that "research staff trained in dietary recall methods observed each meal and snack at school and recorded each child's intake; these data were incorporated into the recall." However, this procedure was not specified in the protocol.
Recruitment bias	Low risk	Individuals were recruited and enrolled prior to cluster randomisation.
Baseline imbalance	Low risk	Participant characteristics at the time of allocation were similar except for child race/ethnicity. This was accounted for in the analyses.
Loss of clusters	Low risk	No reported loss of clusters, with small numbers of children lost to follow‐up.
Incorrect analysis	Low risk	Study authors stated that "Mixed models were used to account for having repeated measures (pre and post) as well as for clustering of children within a classroom."
Contamination	Low risk	Study authors stated that "The 6 teaching teams (hereafter referred to as “classrooms”) within each agency were randomly assigned by using an automated system overseen by the study statistician to 1 of 3 study arms, with the limitation that each agency have 2 classrooms allocated per study arm and that the classrooms were located in different communities to prevent cross‐contamination."
Other bias	Low risk	No clear other source of bias