Black 2010.

Study characteristics
Methods	Study design: RCT Intervention period: 12 weeks Follow‐up period (post‐intervention): 21 months Differences in baseline characteristics: reported Reliable outcomes: reported Protection against contamination: NR Unit of allocation: individual Unit of analysis: individual
Participants	N (controls baseline) = 114 N (controls follow‐up) = 93 (1st follow‐up); 90 final N (interventions baseline) = 121 N (interventions follow‐up) = 91 (1st follow‐up); 89 final Setting (and number by study group): home‐ and community‐based Recruitment: 2 samples: N = 84 participated in a longitudinal investigation of growth and development (17.9% experienced growth faltering by age 2 years, but by age 6 years growth had recovered) N = 151 recruited from middle schools Geographic region: resident in low‐income communities surrounding a mid‐Atlantic urban, university medical centre Percentage of eligible population enrolled: NR Mean age: intervention + control: 13.3 (11‐16) Sex: intervention + control: 49% female
Interventions	To evaluate a 12‐session, home‐ and community‐based health promotion/obesity prevention programme. A manualised 12‐session (12‐week) intervention based on SCT, developed with a board of African American adolescents, and a rap music video promoting healthy eating and PA. Principles of mentorship (role modelling and support), participatory learning, and goal‐setting were central to the intervention. Participants were paired with race‐ and gender‐matched college‐enrolled (age 19‐25 years) mentor. Mentoring took place in both the home and the community (mentors accompanied the adolescents to neighbourhood convenience stores and playgrounds to promote healthy dietary choices and PA). In addition to setting dietary and PA goals, tracking and evaluating progress and revising goals as necessary, intervention adolescents made and tasted healthy snacks and engaged in PA. Diet and PA combined intervention vs control
Outcomes	Outcome measures Primary outcome: zBMI, % overweight or obese, % body fat, fat mass, fat‐free mass Secondary outcomes: PA, dietary intake Process evaluation: reported (fidelity)
Implementation‐related factors	Theoretical basis: SCT and MI Resources for intervention implementation: NR Who delivered the intervention: reported PROGRESS categories assessed at baseline: child: gender, race/ethnicity; parent: education, SES, social status PROGRESS categories analysed at outcome: child: gender Outcomes relating to harms/unintended effects: NR Intervention included strategies to address diversity or disadvantage: NR Economic evaluation: NR
Notes	Funding: this research was supported by grant R40MC00241 from the Maternal and Child Health Research Program, US Department of Health and Human Services to Maureen Black, Ph.D., and the University of Maryland General Clinical Research Center grant M01 RR16500, General Clinical Research Centers Program, National Center for Research Resources (NCRR), NIH Mentors received approximately 40 h of training, including MI and had weekly supervision during the intervention
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly stratified by growth history, weight status, gender and age, no further details
Allocation concealment (selection bias)	Unclear risk	NR
Blinding (performance bias and detection bias) All outcomes	Low risk	Research assistants were unaware of participants' intervention status or baseline data re collection of anthropometric measures
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss is overall < 30% and ITT analyses were conducted
Selective reporting (reporting bias)	Low risk	Trial registration document checked. All outcomes reported
Other bias	Low risk	No additional threats to validity