De Coen 2012.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 2 years Unit of allocation: communities (a local authority ‐ town or municipality) Unit of analysis: child
Participants	Service type: centre‐based (pre‐primary school) Operation: not reported Country (region): Belgium (Flanders) Country income classification: high Low‐SES sample: no Population description: the 6 communities were selected from the research regions in Flanders, Belgium disposed by the Flemish Policy Research Centre for Welfare, Health and Family, which commissioned the research project. The selection of these 6 communities out of the research regions was based on 5 socioeconomic characteristics: (i) the number of births in underprivileged families; (ii) the proportion of pupils in primary school with a school delay; (iii) the rate of unemployment; (iv) the number of people on welfare support; and (v) the number of underprivileged foreigners. High scores on these parameters are indicators of a lower socioeconomic profile. Inclusion criteria: the selection of these 6 communities out of the research regions was based on 5 socioeconomic characteristics: (i) the number of births in underprivileged families; (ii) the proportion of pupils in primary school with a school delay; (iii) the rate of unemployment; (iv) the number of people on welfare support; and (v) the number of underprivileged foreigners. High scores on these parameters are indicators of a lower SES profile. If a community scored higher than the Flemish mean on 3‐5 of the abovementioned characteristics, it was labelled as ‘low SES’; communities with 1 or 2 scores higher than the Flemish mean were labelled as ‘medium SES’; and communities with no scores higher than the mean were labelled as ‘high SES’. 2 communities had a high, 2 had a medium and 2 had a low‐SES profile. Exclusion criteria: not reported Number of services randomised: 6 communities (18/32 schools participated in intervention, 13/17 schools participated in control) Number of children randomised: 1589 participated Characteristics Children Age: 4.95 years (SD 1.31) Gender (% female): 50% Ethnicity: not reported Parents Age (years): not reported Gender (% female): not reported Ethnicity: not reported Parent/family SES: not reported Method of recruitment: recruitment of the participants took place in pre‐primary and primary schools. Missing data/dropout: 46% dropout: 586 children dropped out for the questionnaire; 178 BMI values could not be attained at follow‐up Reasons for dropout: for BMI only: due to absence on the day of the measurement or change of school Characteristics of dropouts: the baseline BMI z‐scores were not significantly different between the communities. There were no other significant differences between intervention and control regions. Over the conditions, participants with a low SES dropped out significantly more at the follow‐up measurement (Chi2 = 10.03, P = 0.001).
Interventions	Programme name: the POP (Prevention of Overweight among Pre‐school and school children) Number of conditions: 1 intervention, 1 control Intervention duration: 2 school years Intervention setting: ECEC and wider community Intervention strategies: Health curriculum Children Education: schools were requested to implement 5 x Healthy Weeks per intervention year (1 for each cluster of topics) with a minimum 1 h of classroom time dedicated to the topic together with extracurricular activities. Ethos and environment ECEC staff Resources: schools received guidelines and a manual describing the modules/objectives, tasks and responsibilities, including theory‐based methods and practical strategies. These 7 modules were: the organisation of the POP project at school level; the organisation of classroom activities (Healthy Weeks), including suggested dose and content; development of an active playground; implementation of health‐related physical education; environmental and policy changes to increase the availability of water at school (e.g. water fountains); environmental and policy changes to increase to availability of vegetables and fruits at school; and, educational strategies for parents on all topics. Meetings: 4 x meetings with the teachers. An implementation plan and problem solving was discussed. Financial support: teachers received EUR 250 to buy materials or finance environmental changes. Service Policy: schools were requested to evaluate and improve their playground and snack and beverage policy. Partnerships Families Resources: parents received a poster, 5 letters and a website link to resources, distributed by the school. Communication: schools were requested to communicate with the parents on the programme and distribute materials to the parents. Community Meetings: 2 x meetings were held in each intervention community with the researchers, community organisations and stakeholders regarding local social and health problems. Engagement: community organisations, members of the city council, aldermen and local non‐profit organisations working with children or health topics were approached to support the intervention at community level, to raise awareness and give greater publicity to the project. Resources: each intervention year, information brochures and posters regarding the 5 topics of the project were distributed through general practitioners, pharmacists, social services and at relevant community events by the regional health boards and the research team. Healthcare Support: regional health boards supported schools and communities to implement the project (making contact with services at least twice/year). Regional health boards received EUR 500. Intensity of intervention: 2 x community meetings to support the development of the intervention; yearly dissemination of information brochures and posters regarding the 5 intervention topics; 5 x Healthy Weeks per intervention year with a minimum of 1 h classroom time dedicated to the topic with extracurricular activities; 4 x teacher meetings; regional health boards contacted services at least twice yearly; parents received a poster, 5 letters and a website link. Intervention delivered by: research team, ECEC staff, healthcare staff Modality: face‐to‐face, telephone, online, written Theoretical basis: Socio‐Ecological Model in health promotion programmes Description of control: usual care
Outcomes	Outcomes relating to child dietary intake: Fruit intake, vegetable intake, milk intake, water intake, soft drink intake, sweet or savoury snack intake Number of participants analysed: Intervention baseline: 1032 Intervention follow‐up: 396 Control baseline: 557 Control follow‐up: 398 Data collection measure: 24‐item semi‐quantitative FFQ Data collector: parent Validity of measures used: validated Outcomes relating to child physical measures: BMI z‐score Number of participants analysed Intervention baseline: 1032 Intervention follow‐up: 670 Control baseline: 557 Control follow‐up: 442 Data collection measure: objectively measured (Flemish reference data using the LMS (curve‐L, mean‐M and coefficient of variation‐S) 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: commissioned, financed and steered by the Ministry of the Flemish Community (Department of Economics, science and Innovation; Department of Welfare, Public Health and Family).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The random sequence generation procedure was not described.
Allocation concealment (selection bias)	High risk	Study authors stated that “Schools were aware of the fact that they were in an intervention community or in a control community.”
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 semi‐quantitative FFQ. 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 by the research team and are not likely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) Diet outcomes	High risk	Data were available for 694 (54%) of sample at follow‐up. Study authors stated that "selective drop‐out may have influenced the outcomes. Although this was not particular for one condition, the low‐SES participants dropped out significantly more." Due to the magnitude of missing data, the risk of bias was assessed as high.
Incomplete outcome data (attrition bias) Physical outcomes	High risk	Data were available for 1112 (70%) of sample at follow‐up, and a higher percentage of the intervention group was lost to follow‐up compared to the control group (35% vs 21%). Of the 477 dropouts, 178 (37%) were due to absence on the day of the measurement or change of school. Study authors stated that "selective drop‐out may have influenced the outcomes. Although this was not particular for one condition, the low‐SES participants dropped out significantly more." Due to the magnitude of missing data and difference in the proportions of participants followed up between groups, the risk of bias was assessed as high.
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	High risk	Individuals and schools were recruited after randomisation of clusters.
Baseline imbalance	Low risk	The baseline BMI z‐scores were not significantly different between the communities. There were no other significant differences between intervention and control regions.
Loss of clusters	Low risk	No apparent loss of clusters
Incorrect analysis	Low risk	Study authors stated that “Children were clustered in thirty‐one schools (nesting variable).” and "the community was entered as a possible moderating factor by investigating the interaction between condition and community."
Contamination	Unclear risk	No evidence to make assessment
Other bias	Unclear risk	Study authors stated that "In some schools, parents experiencing language or other problems filling in the questionnaire were assisted by an intercultural worker or interpreter." However, it is not mentioned that the parental intervention itself was offered in multiple languages, introducing possible bias, especially if language barriers were higher in one group versus another. There is insufficient information to assess whether an important risk of bias exists.