Zheng 2007.

Methods	Study design: Randomized controlled trial Country: China Recruitment: Community volunteers Group size: 13 ‐ 15
Participants	232 smokers (no minimum daily amount specified); 94% men, av. age 56 in I, 53 in C (P < 0.05) Therapists: health education professionals
Interventions	1. Social cognitive group intervention, 5 x 2‐hr twice‐weekly sessions 2. Waiting‐list control
Outcomes	Sustained abstinence at 6 m Validation urine cotinine < 25 ng/ml
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Participants took paper marked 1 or 2 from a box
Allocation concealment (selection bias)	High risk	Possibility that allocation could be changed
Blinding of outcome assessment (detection bias) All outcomes	High risk	Biochemical validation of abstinence
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 lost to follow‐up in I, 11 in C, included in ITT analysis

ALA: American Lung Association
 ACS: American Cancer Society
 av: average (mean)
 BDI: Beck's Depression Index
 CBT: cognitive behavioural therapy
 CO: Carbon Monoxide
 cpd: cigarettes per day
 FTQ: Fagerstrom Tolerance Questionnaire
 hr: hour(s)
 m: month(s)
 MDD: Major Depressive Disorder
 min: minute.
 NCI: National Cancer Institute
 NRT: nicotine replacement therapy
 NS: statistically non‐significant
 PPA: Point prevalence abstinence
 ppm: parts per million
 RP: Relapse prevention
 Rx: treatment
 S‐H: self‐help.
 sig diff: statistically significant difference
 TCN: thiocyanate
 TQD: Target Quit Day
 vs: versus
 wk: week(s)
 yr: year(s)