Results Across follow-ups, abstinence was significantly greater for smokers in the DEG (34%) compared with the SEG (25.8%; OR=1.47, 95% CI 1.07 to 2.02, p=0.02) but there was no difference between the BEG (30.8%) and the SEG (p=0.13). Results were independent of baseline cigarettes per day, interest in quitting, smoker in household, use of nicotine replacement therapy (NRT) or varenicline and gender, themselves associated with abstinence (ps<0.05). Missing=smoking and multiple imputation analyses based on 25 data sets corroborated results. Participants in the DEG were also more likely to use non-medication aids (eg, quit smoking website, cessation class/clinic) compared with the SEG (OR=1.34, p=0.02, CI 1.06 to 1.71), but use of these or NRT by the 4-week follow-up (vs no use) increased abstinence across follow-ups primarily for those in the SEG.