Kornilaki 2021.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 3 months Unit of allocation: nursery schools Unit of analysis: child
Participants	Service type: centre‐based (nursery schools) Operation: not reported Country (region): Greece (Heraklion region of Crete) Country income classification: high Low‐SES sample: unclear Population description: not reported Inclusion criteria: parents were eligible if they were Greek speakers (for questionnaire purposes only). Exclusion criteria: not reported Number of services randomised: 15 (groups not reported) Number of children randomised: 329 (184 intervention, 145 control) Characteristics Children Age: Intervention: 5.03 years (SD 0.54) Control: 5.05 years (SD 0.54) Gender (% female): Intervention: 50% Control: 54.5% Ethnicity: not reported Parents Age (years): Intervention: mother: 37.69 (SD 6.2); father: 40.83 (SD 5.4) Control: mother 37.28 (SD 4.96); father: 40.66 (SD 6.08) Gender (% female): not reported Ethnicity: not reported Parent/family SES: Family income Intervention: up to EUR 14,999, 37.61%; EUR 15,000‐29,999, 47.86%; EUR 30,000‐49,999, 10.26%; > 50,000 euros, 4.27% Control: up to EUR 14,999, 46.66%; EUR 15,000‐29,999, 48%; EUR 30,000‐49,999, 2.67%; > EUR 50,000, 2.67% Mothers' education Intervention: compulsory: 4.24%; high school: 27.12%; technical/vocational: 33.05%; university: 35.59% Control: compulsory: 7.79%; high school: 28.57%; technical/vocational: 28.87%; university: 33.77% Fathers' education Intervention: compulsory: 11.86%; high school: 34.74%; technical/vocational: 23.74%; university: 29.66% Control: compulsory: 16.88%; high school: 32.87%; technical/vocational: 28.18%; university: 22.07% Method of recruitment: all nursery schools in the Heraklion area were invited to participate in the study through phone and email. After organisational approval was given, all educators in each nursery school were verbally invited to the research project and informed consent was obtained. All eligible parents of children in the nursery school were invited to participate through information provided by the educators received directly from the researcher. Missing data/dropout: 26 of 329 did not return the eating and physical activity questionnaire at any time point and were withdrawn from the sample. All 3 time points were returned by 137 parents, 113 parents returned 2 questionnaires and 53 parents returned only 1. Reasons for dropout: not reported Characteristics of dropouts: not reported
Interventions	Programme name: not reported Number of conditions: 1 intervention, 1 control Intervention duration: 4‐6 weeks Intervention setting: ECEC Intervention strategies: Health curriculum Children Education: educators delivered the curriculum they had developed (tailored to each class) following training. Ethos and environment ECEC staff Training: 2 x 2‐h professional learning sessions were delivered by trained researchers to the nursery school educators to build the educator’s capacity to develop age‐appropriate educational curriculum activities that increased young children’s healthy eating habits, raised children’s environmental consciousness and provided physical activity opportunities, while engaging their popular culture interests. Educators were encouraged to follow 4 best practice principles when delivering the curriculum: implementing the curriculum experiences in the morning when most cognitively alert; using a combination of 3 identified play types; conducting the curriculum activities 2–3 times/week for between 4 and 6 weeks; and, using a range of real‐life props as resources. Support: researcher support via telephone and email was provided. Intensity of intervention: 2 x 2‐h professional learning sessions were delivered to staff; delivery of curriculum activities 2‐3 times/week by educators Intervention delivered by: research team, ECEC staff Modality: face‐to‐face, telephone, online, written Theoretical basis: Funds of Knowledge Description of control: wait‐list control
Outcomes	Outcomes relating to child dietary intake: Fruit and vegetables intake, unhealthy food (packaged snacks, chocolates and confectionary, flavoured milk, cakes and sweet biscuits) intake, sugar sweetened beverages intake, unsweetened beverages (unflavoured milk and water) intake, fruit intake, vegetable intake Number of participants analysed: Intervention baseline: 107‐150 Intervention follow‐up: 115‐119 Control baseline: 86‐114 Control follow‐up: 70‐77 Data collection measure: eating and physical activity questionnaire (EPAQ) Data collector: parents Validity of measures used: validated Outcomes relating to child physical measures: BMI Number of participants analysed: not reported Data collection measure: objectively measured (IOTF) Data collector: not reported 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: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Nursery schools were randomly allocated to the intervention and control groups through a computer‐generated random number allocation.
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	We assumed that due to the nature of the intervention, ECEC service staff and study personnel delivering the intervention were not blind to the study allocation. The outcome is likely to be influenced by lack of blinding.
Blinding of participants and personnel (performance bias) Physical outcomes	Low risk	We assumed that due to the nature of the intervention, ECEC service staff and study personnel delivering the intervention were not blind to the study allocation. However, the outcome is not likely to be influenced by lack of blinding.
Blinding of outcome assessment (detection bias) Diet outcomes	High risk	Parents completed the Eating and Physical Activity Questionnaire to report children's dietary intake. Blinding of parents not reported, and the outcome measurement is likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) Physical outcomes	Low risk	Blinding not reported, however children's height and weight were measured and were not likely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) Diet outcomes	Unclear risk	Data from the Eating and Physical Activity Questionnaire for at least 2 time points are available for 142 (77%) children in the intervention group and 108 (74%) of the control group. However, it is not known whether those who only submitted 2 questionnaires had completed the baseline questionnaire. Reasons for missing data not provided. Risk of attrition bias is unclear.
Incomplete outcome data (attrition bias) Physical outcomes	Low risk	Data were available for 177 (96%) participants in the intervention group and 138 (95%) students in the control group at immediate post‐intervention, and 167 (91%) students in the intervention group and 133 (92%) students in the control group at 3‐month follow‐up. Loss to follow‐up is similar across both groups and within reason (< 10%). Therefore, risk of attrition bias was considered to be low.
Selective reporting (reporting bias)	Low risk	The outcomes reported in the paper were prespecified in the protocol paper.
Recruitment bias	Unclear risk	It is unclear whether individuals were recruited to the study before or after randomisation of clusters.
Baseline imbalance	Unclear risk	No significant differences in demographic characteristics were noted between trial groups, except for father's height. However, demographic data weren't obtained until 3 months post‐intervention. Study authors also state that "Finally, no data were collected about the demographics of each classroom (for example, educator/child ratios) or their educators (years of experience)."
Loss of clusters	Unclear risk	Not reported
Incorrect analysis	High risk	There was no accounting for clustering of children within schools.
Contamination	Unclear risk	No evidence to make assessment
Other bias	High risk	No funding statement was provided.