Models were first fit to estimate the main effects of medication and counseling conditions and the relationship of AGES with risk for smoking lapse, followed by an evaluation of whether this relationship differed for those allocated to bupropion or placebo (AGES × drug interaction). This primary moderation (AGES × drug) analysis was followed by the removal of AGES index for a post-hoc estimate of the set of four individual genetic risk indices representing a count of respective hypothesized risk alleles (range 0–2). All statistical analyses, tables, and figures were generated using R statistical software (http://www.r-project.org/) packages coxme (51), rms (52) and LME4 (53).
