Elder 1996.

Methods	Country: USA Sites: 96 schools in Texas, California, Louisiana and Minnesota (10 schools at each site randomised to control, 7 to school‐based intervention, 7 to school and family). 'CATCH' study (The Child and Adolescent Trial for Cardiovascular Health). Focus: cardiovascular health promotion. Design: Cluster RCT (Group 1: never smoking prevention cohort).
Participants	Baseline: N at end of 5th grade: 7827, of whom 6527 gave complete information. Age: 5th graders (age 10 ‐ 11). Gender: 51% F. Ethnicity: 71% W, 16% H; 14% A‐A. Baseline smoking data: Intervention 3845 of whom 181 ever‐smoked; Control 2682, of whom 134 ever smoked.
Interventions	Category: Social influences vs control. Programme deliverer: Teachers Intervention: 4 x 50 min sessions. CATCH used social learning theory and organizational change to intervene in school environments, class room curricula, family interventions and school smoking policies to change smoking status and cardiovascular health. CATCH intervention began in 3rd grade cohort but smoking prevention curriculum not introduced until 5th grade. School‐based intervention: Facts and Activities about Chewing Tobacco and Smoking (FACTS for 5) [dangers, costs, and aversive aspects of tobacco; benefits of not using tobacco; being tobacco‐free is the most acceptable way of life now]. School and Home intervention: The Unpuffables was a 4 session programme from the American Lung Association to be used to complement each school lesson. Control: No intervention.
Outcomes	% of schools with smoke‐free policies. Smoking prevalence Follow‐up: 3 yrs.
Notes	Quality of intervention delivery: Of the children who began in a school which offered the school + family intervention, 47% attended such a school for the entire 3 yrs. The process analysis for the FACTS tobacco curriculum showed that 87% of teachers participated in the classroom sessions; checklists were returned for 96% of classroom sessions; 96% completed the entire lesson; and 87% were implemented without modification. For the Family Intervention for tobacco 97% of session‐specific activities were completed; 78% of adults participated in the home activities; and 48% of home team activity cards were returned; one third of schools held assemblies about tobacco; 40% participated in 'Great American Smokeout' activities; and 25% sponsored anti‐tobacco or anti‐drug clubs. Statistical quality: Was a power computation performed? No (study not designed to find a difference in smoking prevalence). Was an intention‐to‐treat analysis performed? Not stated. Was a correction for clustering made? Not stated. Were appropriate statistical methods used? Analysis was by multiple LR (including a school random effect), but school effects were not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Ten schools at each site were randomly assigned to the control condition and 7 schools each to a school‐based intervention (food service, physical education, classroom curricula) or the school‐based plus family intervention program". Clusters: School Cluster constraint: Not stated. Baseline comparability: No report of differential characteristics at baseline.
Allocation concealment (selection bias)	Unclear risk	No statement
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No statement
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	100% of 3rd grade teachers and 67% of students attended Family Fun Nights; 100% of schools remained in the dietary assessment process; no attrition analysis.
Selective reporting (reporting bias)	Low risk	No selective reporting.