Treu 2017

Methods	Study design: Cluster‐randomised controlled trial Unit of randomisation: Schools N schools (randomly assigned): 17 (8 standard arm, 9 enhanced arm); 9 control schools not randomly assigned Unit of analysis: Child Intervention duration: 1 school year Follow‐up: Immediately post‐intervention Setting: East Jackson County, Missouri, USA Classification of weight status: CDC growth charts for overweight and obesity (2000) Start and end date: 2010 ‐ 2011 school year
Participants	N (randomised): 360 (89 standard arm, 115 enhanced arm, 156 control) N (followed): 349 (85 standard arm, 114 enhanced arm, 150 control) Age range: 8 ‐ 10 years Mean age: Standard intervention 8.7 ± 0.4 years, enhanced intervention 8.7 ± 0.4 years, control 8.7 ± 0.5 years Sex: Standard intervention 45% female, enhanced intervention 50%, female, control 49% female Overweight: Data not available Obesity: Data not available Ethnicity: Standard intervention: White 60%, Hispanic 4%, black 9%, other 8% Enhanced intervention: White 59%, Hispanic 19%, black 13%, other 9% Control: White 31%, Hispanic 15%, black 51%, other 3% Reason for attrition (missing data): Schools did not provide outcome data Attrition rates: Zero for most academic outcomes and very low, with 2% for reading comprehension in the enhanced intervention arm
Interventions	Comparisons: Standard intervention versus wait‐list control; Enhanced intervention versus wait‐list control Standard intervention: "Consisted of the Nutrition Detectives (ND) programme and the ABC for Fitness (ABC) programme offered in grade 3. These 2 programmes had already been incorporated into the curriculum and offered annually beginning a few years before the start of this study." 1. Physical activity: "ABC for Fitness offers brief ‘bursts’ of physical activity in the classroom, each of a few minutes in length, spread over the school day. Classroom teachers offered 30 daily minutes of activity bursts throughout the school year. The activity bursts were designed to include a brief warm‐up and cool‐down (e.g. stretching or low‐intensity activity) along with 1 or more core activities of higher intensity (e.g. hopping, running in place, jumping jacks, or dancing to music). Teachers were provided with an ABC manual with guidelines and activity suggestions. The programme structure was flexible and allowed for teachers to be creative in selecting warm‐ups/core activities/cool‐downs, determining the timing and length of individual activity bursts, and deciding how best to incorporate them into the school day (i.e. whether as a break from lessons or incorporated into the lessons)." 2. Health nutrition/lifestyle education: "ND is a 90‐minute programme, delivered by PE teachers, that aims to convey the link between food choices and health, convince students of the need to become ‘‘supermarket spies’’ to learn the truth about the foods that they eat, and provide ‘‘five clues’’ to distinguish between more healthful (‘‘clued‐in’’) and less healthful (‘‘clue‐less’’) food choices based on the Nutrition Facts labels and ingredient lists on food packages." "At month 3 participants received a 30‐minute booster session." Enhanced intervention: Included the ND and ABC programmes plus reinforcements of their messages to participants and their families in the school, home, and a supermarket 1. Physical activity: As above. "In addition, family‐focused kits were sent home including pedometers, walking tips to increase daily steps, a family log for recording steps, local walking trail guides, walking maps for local grocery stores, physical activity tip sheet, suggestions for ‘activity bursts’, family activity challenge cards, a 3‐minute sand timer to be used for activity challenges, and a log to record the number of activities and repetitions completed." "For each family kit, students were encouraged to return the completed assignments or logs for a small prize. A family night was held in schools and focused primarily on physical activity: families visited stations throughout the building to try out different kinds of exercises, including Frisbee golf and Zumba, and received information or coupons from local fitness‐related businesses." 2. Healthy nutrition/lifestyle education: As above. "Schools also received articles related to health, nutrition, or physical activity to include in their monthly school newsletters." In addition, "a family‐focused kit was sent home which included a Nutrition Detectives DVD; a reminder card with the programme’s "five clues" to make healthful food choices; grocery store coupons; and a family "homework assignment" to watch the DVD, review the ND clues together, complete an activity applying the clues to foods in the family kitchen, and informational materials on the NuVal Nutritional Scoring System." "A family night was held at the local supermarket, with stations set up to teach families about healthful food choices with games, demonstrations, and taste tests." Wait‐list control: "Control schools received a delayed intervention (ND and ABC programmes) during the school year after study completion." Schools were allowed to continue any programming that they would usually offer, which consisted of physical education classes but no classroom‐based programmes involving nutrition education or physical activity."
Outcomes	1. School Achievement: AIMSweb standardised test scores: Maze reading test (reading comprehension); Reading Curriculum‐Based Measurement (reading fluency); Mathematics Concepts and Applications (math problem‐solving skills); Mathematics Curriculum‐Based Measurement (computation performance) 2. Obesity indices: Measured weight and height fully‐clothed but were instructed to remove shoes and any heavy outerwear such as jackets or sweaters. Calculated BMI z‐scores
Notes	Authors provided raw data for characteristic and outcome data for children with obesity or overweight The sample size calculation was based on the total study sample (participants in any weight group). Funding source: Health Care Foundation of Greater Kansas City
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote: "One school district’s 17 elementary schools were randomly assigned to either the SI [standard intervention] group (eight schools) or EI [enhanced intervention] group (nine schools), with the other district’s nine elementary schools serving as the control group." Judgement comment: The districts were not randomised, only intervention arms were randomised.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: No details reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: Blinding not possible for this type of intervention. The primary aim of the study was obesity prevention and so it was unclear if the participants and teaching personnel were aware of potential effects on academic achievement
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "These tests are used in schools across the United States as screening and progress monitoring tools." Judgement comment: Assessment seemed centralised and took place for all students in the year group regardless of participation in the study
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "All analyses were based on the intention‐to‐treat principle using the baseline measure carried forward." Judgement comment: Attrition rates were zero for most academic outcomes and very low, with 2% for reading comprehension in the enhanced intervention arm
Selective reporting (reporting bias)	Unclear risk	No reference to a trial register entry or published study protocol
Comparability of baseline groups	High risk	Judgement comment: Comparison of baseline characteristics between the intervention and control schools for the total study sample suggested considerable group differences in ethnicity, BMI z‐scores, physical fitness, nutrition knowledge and mathematical computation skills. Group differences for ethnicity were also present for the subgroup of children with overweight/obesity, based on author‐provided unpublished data
Cross‐contamination	Low risk	Quote: "One school district’s 17 elementary schools were randomly assigned to either the SI group (eight schools) or EI group (nine schools), with the other district’s nine elementary schools serving as the control group." Judgement comment: Separate district for control group
Other bias	Low risk	Judgement comment: None detected