| Methods |
Country: UK
Setting: schools in West Midlands
Study design: cluster‐RCT. Schools sampled with probability in proportion of size of year group. Combined prevention/cessation trial |
| Participants |
Participants: 1089 adolescent smokers (defined as ≥ 1 cpw) (I = 547; C = 542)
Age range: 13‐14 years
Criteria for inclusion: inclusion was at level of school; 89 schools approached, 53 agreed to participate. Data extracted for this cessation review based on all pupils in year 9 who smoked ≥ 1 cpw
Follow‐up method: questionnaire to all students
Inducements to enter study: none
Pre‐study smoking status assessment: self‐reported
Post‐study smoking status assessment: self‐reported
Significant demographic differences between arms of trial: none apparent in published data |
| Interventions |
Intervention: computer 'expert system' designed to diagnose stage of change and deliver material tailored to individual. 6 sessions, 2 per term, 1 class‐based (tutor training mandatory) and 1 computer‐based delivered over period of school year (3 school terms per year in UK)
Theoretical basis of intervention: psycho‐social intervention based on Transtheoretical Model of Stages of Change
Control: control schools received health education as delivered locally at that time; in addition teachers received 3 lesson plans plus handouts but no specialist training or record of what was delivered.
Theoretical basis of control: normal local practice |
| Outcomes |
Measurement: 7‐day and 30‐day PPA (supplied by study author); follow‐up periods > 3 months, 12 months (mean length of follow‐up 359 (I) to 347 (C) days) and 24 months from start of study, equivalent to 4 months and 16 months after end of intervention
Verification: none
Losses to follow‐up: 11% (I) and 10.7% (C) at 12 months; 14% (I) and 16.9% (C) at 24 months (additional data from study authors) |
| Notes |
This review uses 12‐month follow‐up for the group of baseline regular smokers, treating those lost to follow‐up as continuing smokers, as reported in Aveyard 1999. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Computer‐generated block randomization, balanced by class size |
| Allocation concealment (selection bias) |
Low risk |
Computerized and anonymous |
| Blinding of participants and personnel (performance bias)
All outcomes |
Unclear risk |
Not specified |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
No biochemical validation, but follow‐up surveys anonymized (identified only by ID number) and delivered by trained personnel in 'examination' setting, differential misreport judged to be unlikely |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Analyses tested all models of losses to follow‐up |
| Other bias |
Unclear risk |
Fidelity of implementation for controls unclear |
