Baseline characteristics (sex, age, race, treatment allocation, cigarettes per day, FTND score, loss to follow-up) were similar across studies (Table 1), although participants in Study 1 reported somewhat higher FTND scores (6 vs. 5, p < 0.05) and smoked more cigarettes per day (25 vs. 22, p < 0.05). The mean age of all participants was 45 years (Standard Deviation [SD] = 12), and mean cigarette consumption was 23 cigarettes/day (SD = 10). There were no significant differences in other baseline measures between active and placebo groups in either study. There were 356 participants in Study 1 and 436 participants in Study 2 with sufficient genotype and smoking outcome data for analyses, constituting the final study population of N=792 for the present investigation.
