Aburto 2011.
| Study characteristics | ||
| Methods | Study design: cluster‐RCT | |
| Participants |
School inclusion criteria: located in the south of Mexico City, classified by the Secretary of Public Education as low socioeconomic status, received benefits from the Federal School Breakfast Program, demonstrated minimum facilities necessary for execution of the intervention, possessed the standard Secretary of Public Education–issued set of sports equipment, enrolled at least 350 students, and consisted of 2 or more classrooms/grades School exclusion criteria: — Student inclusion criteria: all students in Grades 4 and 5 Student exclusion criteria: — Setting: school, urban Age group: children Gender distribution: females and males Country/Countries where trial was performed: Mexico |
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| Interventions |
Intervention 1 ‐ Basic: environmental and policy changes at the school level meant to foster an environment conducive to increased PA. These changes were complemented with an educational campaign to increase students’ and school staff’s awareness of the importance of PA for health Intervention 2 ‐ Plus: all components of the basic intervention plus additional changes requiring more resources such as an added daily exercise session held before classes began, in which all students participated Comparator: control group experienced no change to the standard practices of public schools in Mexico City related to PE (once/week) and recess (non‐existent) Duration of intervention: 6 months Duration of follow‐up: 6 months Number of schools: 27 Theoretical framework: reciprocal determinism |
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| Outcomes | BMI Fitness |
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| Study registration | — | |
| Publication details |
Language of publication: English Funding: non‐commercial funding (governmental organisation) Publication status: peer‐reviewed journal |
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| Stated aim for study | "The objective of this investigation was to test the effect of a school‐based environmental intervention on PA and physical fitness of students attending public primary schools in Mexico City" | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote from publication: "using a statistical program to draw a random sample from the complete list of eligible schools, 27 schools were randomly chosen for inclusion. Using the same program to draw 3 samples from the 27, the 3 intervention groups were randomly generated" |
| Allocation concealment (selection bias) | Unclear risk | Comment: not described |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Quote from publication: "the nature of the environmental intervention precluded blinding of the participants or field staff" |
| Blinding of outcome assessment (detection bias) All outcomes | High risk |
Quote from publication: "data analysts and researchers were blinded to the meaning of all numeric codes until data analyses were complete" Comment: outcome assessors not blinded |
| Incomplete outcome data (attrition bias) Anthropometrics, Fitness | Low risk | Comment: low loss to follow‐up for outcome measures |
| Selective reporting (reporting bias) | High risk | Comment: anthropometry not reported; only P value for fitness |
| Cluster RCT ‐ Recruitment bias | High risk | Comment: data collected after randomisation |
| Cluster RCT ‐ Baseline imbalance | Low risk | Comment: accounted for in analysis |
| Cluster RCT ‐ Loss of clusters | High risk | Comment: 3 clusters from control group lost to follow up due to time constraints |
| Cluster RCT ‐ Incorrect analysis | Low risk | Quote from publication: "robust standard error accounting for the design effect of school were calculated" |