Kocken 2016.
| Study characteristics | ||
| Methods | Study design: cluster‐RCT | |
| Participants |
School inclusion criteria: — School exclusion criteria: — Student inclusion criteria: 9 to 11 years Student exclusion criteria: — Setting: school, mix Age group: children Gender distribution: females and males Country/Countries where trial was performed: The Netherlands |
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| Interventions |
Intervention: the intervention Extra Fit! comprised a variety of theory and practical lessons on nutrition and PA to provide an attractive programme for children. The intervention was focused on the main behavioural changes: decreasing consumption of high‐energy or high‐fat foods and sugar‐sweetened drinks; promoting a healthy breakfast; increasing consumption of fruits and vegetables; reducing television viewing and computer gaming or browsing; and increasing PAs at school and outside school hours. Behavioural determinants of the Theory of Planned Behaviour that were targeted were knowledge (theory lessons and practical assignments), attitude (group discussions and food diaries), social norm (group discussions and homework assignments), and perceived behavioural control (modelling through assignments, e.g. preparing a healthy meal and PA games) Comparator: regular school programme or curriculum on nutrition and PA Duration of intervention: 2 × 16 weeks Duration of follow‐up: 24 months Number of schools: 45 Theoretical framework: theory of planned behaviour |
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| Outcomes | PA duration Sedentary time BMI |
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| Study registration | — | |
| Publication details |
Language of publication: English Funding: non‐commercial funding (research funding body) Publication status: peer‐reviewed journal |
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| Stated aim for study | "The aim of Extra Fit! was to improve dietary habits, PA and inactivity behavior in order to prevent overweightness" | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Comment: not described |
| Allocation concealment (selection bias) | Unclear risk | Comment: not described |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Comment: participants could not be blinded to intervention |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Comment: interviewers were blinded with respect to group status of the child’s school (intervention or control) for nutrition interviews, not other measures |
| Incomplete outcome data (attrition bias) Anthropometrics, Fitness | High risk | Comment: large loss to follow‐up |
| Incomplete outcome data (attrition bias) Physical activity and sedentary time | High risk | Comment: large loss to follow‐up |
| Selective reporting (reporting bias) | Unclear risk | Comment: no protocol |
| Cluster RCT ‐ Recruitment bias | Low risk | Comment: all students within randomised schools enrolled |
| Cluster RCT ‐ Baseline imbalance | Low risk | Comment: hip‐waist ratio was significantly higher in the control group at time 0 (t‐test, P < 0.01). There were no other significant differences in baseline characteristics between intervention and control groups |
| Cluster RCT ‐ Loss of clusters | High risk | Comment: 20/65 schools dropped out after randomisation; 7 schools lost to follow‐up after intervention began |
| Cluster RCT ‐ Incorrect analysis | Low risk | Quote from publication: "outcome analyses were conducted using multilevel regression models, with schools included as a random effect" |