Kobel 2019.

Study characteristics
Methods	Study design: cluster‐RCT Length of follow‐up from baseline: 1 year Unit of allocation: kindergartens Unit of analysis: child
Participants	Service type: centre‐based (kindergartens) Operation: not reported Country (region): Germany (South‐West Germany) Country income classification: high Low‐SES sample: unclear Population description: not reported Inclusion criteria: only kindergartens that had not previously taken part in the programme were included in the study. Children within the recruited kindergartens were eligible if they were between 3 and 5 years old at the time of baseline measurements and their parents provided a signed consent form. Exclusion criteria: not reported Number of services randomised: 57 (30 intervention, 27 control) Number of children randomised: 973 (318 participated intervention, 240 participated control) Characteristics Children Age: 3.6 years (SD 0.6) Gender (% female): 47.7% Ethnicity: migration background: 33.4% Parents Age (years): not reported Gender (% female): not reported Ethnicity: not reported Parent/family SES: not reported Method of recruitment: participating kindergartens were recruited from all kindergartens in southwest Germany, which had received written information about programme and study, asking interested kindergarten teachers to participate. Missing data/dropout: 57% dropout Reasons for dropout: not reported Characteristics of dropouts: not reported
Interventions	Programme name: Join the Healthy Boat Number of conditions: 1 intervention, 1 control Intervention duration: 12 months Intervention setting: ECEC and home Intervention strategies: Health curriculum Children Education: the intervention materials consisted of 20 exercise and games lessons and 30 ready‐to‐use ideas, action alternatives and lessons promoting increased physical activity, reduced screen media consumption, and a more healthy diet, including the reduction of sweetened drinks and an increased fruit and vegetable intake. Ethos and environment Children Exposure: short activity games (exercises of 5–7 min each, which also promote children's motor skills) were used twice daily. ECEC staff Training: kindergarten teachers were trained twice in 16 h of peer‐to‐peer training courses. Resources: kindergarten teachers received instructional and behavioural educational resources. Partnerships Families Resources: family homework, materials for parents' nights and parental letters were provided in 3 languages. Intensity of intervention: 2 x 16 h of peer‐to‐peer training (by teachers); all intervention materials are integrated into the everyday life of kindergartens so no external staff or extra time was required; 20 exercise and games lessons and 30 ready to use ideas, action alternatives and lessons for children Intervention delivered by: ECEC staff Modality: face‐to‐face, written Theoretical basis: Bandura's Socio‐Cognitive Theory and Socio‐Ecological approach Description of control: usual care
Outcomes	Outcomes relating to child dietary intake: Fruit and vegetable intake, sugar sweetened beverage intake Number of participants analysed: Intervention baseline: 318 Intervention follow‐up: 318 Control baseline: 240 Control follow‐up: 240 Data collection measure: parent questionnaire Data collector: parent Validity of measures used: not reported Outcomes relating to child physical measures: BMI percentile Number of participants analysed: Intervention baseline: 538 Intervention follow‐up: 318 Control baseline: 435 Control follow‐up: 240 Data collection measure: objectively measured (German reference data) 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: the kindergarten‐based health promotion programme “Join the Healthy Boat” and its evaluation study was financed by the BadenWürttemberg Foundation (grant number BWS_1.479.00_2009).
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)	Unclear risk	No information on the method of allocation concealment reported
Blinding of participants and personnel (performance bias) Diet outcomes	High risk	No clear blinding of participants and personnel to study allocation, and the outcome is likely to be influenced by lack of blinding.
Blinding of participants and personnel (performance bias) Physical outcomes	Low risk	No clear blinding of participants and personnel to 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 reported dietary patterns via questionnaire. 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 trained technicians and were not likely to be influenced by lack of blinding.
Incomplete outcome data (attrition bias) Diet outcomes	High risk	Follow‐up data are available for 558 (57%) of the children who were assessed at baseline. At baseline, 18% of dietary data were missing, while 30% of dietary data were missing at follow‐up. Reasons for missing data are unclear, and the distribution of loss between groups is not noted. Due to the magnitude of missing data, the risk of bias was assessed as high.
Incomplete outcome data (attrition bias) Physical outcomes	Unclear risk	Follow‐up data are available for 558 (57%) of the children who were assessed at baseline. At baseline, 14% of BMI percentile data were missing, while 14% of BMI percentile data were missing at follow‐up. Reasons for missing data are unclear, and the distribution of loss between groups is not noted. Risk of attrition bias is unclear.
Selective reporting (reporting bias)	Unclear risk	Protocol states variables for nutrition include consumption of sugar‐sweetened beverages, fruit, vegetables, and high‐calorie foods. Data on consumption of high‐calorie foods are not reported in the study. Further, the protocol states variables for anthropometric parameters include waist circumference, waist‐to‐height ratio, BMI, and subcutaneous fat. Only BMI percentile outcomes are reported in the study.
Recruitment bias	Unclear risk	It is unclear whether individuals were recruited to the study before or after randomisation of clusters.
Baseline imbalance	Low risk	No baseline differences were noted between groups for any relevant variables except for gender. The researchers controlled for gender in the analysis.
Loss of clusters	High risk	After randomisation, 4 kindergartens with 22 kindergarten teachers dropped out, mainly due to personnel and organisation issues, resulting in 376 partaking kindergarten teachers and 62 heads of kindergartens. It is not stated which group these clusters were randomised to.
Incorrect analysis	High risk	There was no accounting for clustering of children within kindergartens.
Contamination	Unclear risk	Study authors state that "Even though, a major strength of this study is its randomised controlled design with a control group, the kindergarten teachers in that group were also very health conscious and have not been “inactive”, which might have led to a strong contamination with other efforts to promote children's health in the control group." There is not enough information provided to assess whether contamination exists.
Other bias	Unclear risk	Study authors stated that "The minimum assumed number was therefore 880 children, the maximum 1120 children. The overall significance level is set to 0.05 (2‐sided). Depending on the number of kindergartens, a small effect size of 0.288 to 0.325 could be achieved for a power of 0.80 for the metric targets." With 558 children at baseline, this study does not appear to be adequately powered. There is insufficient information to assess whether an important risk of bias exists. No conflict of interest statement was reported.