Melnyk 2013

Methods	Study design: Cluster‐randomised controlled trial Unit of randomisation: Schools N schools: 11 (distribution between intervention and control unclear) Intervention duration: 15 weeks Follow‐up: Immediately post‐intervention Unit of analysis: Adolescent Setting: Arizona, USA Exclusion criteria: Aged < 14 years (unlikely to have sufficient cognitive development to benefit from the proposed intervention), aged > 16 years (cognitive development of and social expectations for older teens requires a more complex and flexible intervention, potentially unavailable for 12‐month follow‐up sessions), medical conditions that would prevent them from participating in the physical activity component of the programme Classification of weight status: CDC growth charts for overweight and obesity Start date: January 2010 End date: December 2012
Participants	N (randomised): 331 (161 intervention, 170 control) N (analysed): 263 (129 intervention, 134 control) Age range: 14 ‐ 16 years Mean age: Intervention 14.8 ± 0.8 years, control 14.7 ± 0.7 years Sex: Intervention 54% female, control 48% female Ethnicity: Intervention: Hispanic 79.5%, black/African American 9.9%, white 7.5%, Native American 1.2%, Asian 1.2%, other 0.6% Control: Hispanic 66.5%, black/African American 10.0%, white=12.9%, Native American 5.9%, Asian 4.1%, other 0.6% Reason for attrition: no longer at school, missed measurement days, asked to be withdrawn (no reasons reported), did not receive the intervention (no reason reported) Attrition rates: None reported
Interventions	Comparison: COPE versus attention control "The attention control programme was administered in a format like that of the COPE intervention and included the same number and length of sessions as the experimental programme, but there was no overlap of content between the 2 programmes." Intervention: The Creating Opportunities for Personal Empowerment (COPE) programme "is a manualised 15‐session educational and cognitive–behavioural skills‐building programme delivered by trained high‐school health teachers." 1. Physical activity: "Each session of COPE contains 15 – 20 minutes of physical activity (e.g. walking, dancing, kick‐boxing movements), not intended as an exercise training programme, but rather to build beliefs in the teens that they can engage in and sustain some level of physical activity on a regular basis. Pedometers were used throughout the intervention in order to reinforce the physical activity education component of COPE. Students were asked to increase their step counts by 10% each week, regardless of baseline levels and to keep track of their daily steps on a tracking sheet so they could calculate a weekly average and determine if they met their weekly goal." 2. Healthy lifestyle education: The COPE Healthy Lifestyles TEEN (Thinking, Emotions, Exercise, Nutrition) Programme "was delivered once a week in students' health course for 15 weeks." "Participants received a COPE manual with homework activities for each of the 15 sessions that reinforced the content and skills in the programme." "A parent newsletter describing the content of the COPE programme was sent home 4 times during the course of the 15‐week programme." Cognitive‐behavioural skills building: Self‐esteem; positive thinking/self‐talk; goal‐setting; problem‐solving; stress and coping; emotional and behavioural regulation; effective communication; personality and communication styles; barriers to goal progression and overcoming barriers Nutritional topics: Food groups and a healthy body; stoplight diet: red, yellow, and green; nutrients to build a healthy body; reading labels; effects of media and advertising on food choices, portion sizes; influence of feelings on eating; social eating; strategies for eating during parties, holidays, and vacations; snacks; eating out Physical activity topics: Energy balance; ways to increase physical activity and associated benefits; heart rate; stretching Attention control: "The Healthy Teens programme was designed as a 15‐week attention control programme to control for the time the health teachers spent in the COPE group. The content was manualised and focused on safety and common health topics/issues for adolescents, such as road safety, dental care, infectious diseases, immunisations, and skin care." Participants "also received a manual with homework assignments each week that focused on the topics being covered in class and were asked to review with his or her parent a newsletter that was sent home with the teens 4 times during the programme." "Attention control participants were provided with a pedometer for use only during the first week and post‐intervention week for assessment purposes only."
Outcomes	Outcome 1: School achievement: Health class grades assessed by school teachers
Notes	The authors kindly provided unpublished data for adolescents with obesity or overweight The sample size calculation was based on the total study sample (participants in any weight group) Funding source: National Institute of Health/ National Institute of Nursing Research 1R01NR012171.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "randomly assigned to receive either the COPE TEEN program or the Healthy Teens attention control program by placing all of the school names in a hat and then randomly drawing them out." Judgement comment: Restricted randomisation. The method is random but it could be easily manipulated. Imbalances in baseline differences between intervention and control participants might indicate inappropriate randomisation
Allocation concealment (selection bias)	Unclear risk	Quote: "The Healthy Teens attention control program by placing all of the school names in a hat and then randomly drawing them out." Judgement comment: Names are essentially concealed in the hat, which offers randomisation and allocation concealment. However names could easily be re‐drawn from the hat. It is unclear who performed the randomisation
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Judgement comment: The trial register entry indicated that this was a double‐blind (Participant, Investigator) trial. Delivering health‐related content in a curriculum‐based Health Class might be a way of blinding the participants. However, the COPE intervention arm also offered active physical activity sessions to which, by nature, participants cannot be blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "Academic achievement was measured with the student's health course grade." Judgement comment: It is unclear if the same teacher who delivered the intervention also assessed academic performance in the health course
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Judgement comment: Academic achievement data were only available at post‐intervention, so assessment of missing data was not possible
Selective reporting (reporting bias)	Low risk	Judgement comment: NCT01704768 registry entry. All relevant outcomes were reported in the study protocol. The authors provided the unpublished outcomes data for adolescents with overweight/obesity
Comparability of baseline groups	High risk	Quote: "There are more male parents participating in the Healthy Teens group than the COPE TEEN group (p = .00). More parents are Hispanic in the COPE TEEN group versus the Healthy Teens group (p = 00). COPE TEEN parents have lower education levels (p = .00) and report more public assistance (p = .00) than Healthy Teens parents. COPE TEEN parents reported lower annual household incomes (p = .00)." Judgement comment: The quote relates to the entire study sample. The authors provided demographic characteristics of the subgroup with overweight/obesity which show similar differences between the experimental groups. The comparability of the experimental groups is at high risk of bias
Cross‐contamination	Low risk	Quote: "The first school district is located in the heart of the metropolitan city with the other district being located within a large suburb, which serves students from all socioeconomic backgrounds." Quote: "The decision was made to randomly assign schools to one of the two interventions (e.g., instead of randomly assigning classrooms within the schools) in order to decrease the probability of cross‐contamination and minimize threats to internal validity."
Other bias	High risk	Quote: "District administrators in both districts chose which schools could participate in the study." Quote: "All participants received incentives for their involvement in the intervention." Judgement comment: Selection bias introduced by financial incentives offered and the selection of schools by District administrators