In this trial, 49.6% of participants relapsed to smoking during the 90-day post-quit follow-up. In the placebo group, slow metabolism based on CYP2A6 genotype predicted decreased relapse risk in comparison to fast metabolism (Hazard Ratio (HR)=0.40, 95%CI=0.19-0.83, p=0.013), adjusted for age and gender. Age and gender did not predict relapse.
