Figure 1. Randomization and Follow-up of Study Participants.

e-Cigarette indicates electronic cigarette.

^aSubgroups sum to greater than 425 because screened individuals could have more than 1 reason for exclusion.

^bPrecluding medical conditions included history of psychosis, schizophrenia, or bipolar disorder (n = 35; 6%); current cancer or in remission for less than 1 year (n = 22; 4%); condition with a prognosis of less than 1 year (n = 7; 1%); and less than 1 month following a major cardiac event (n = 5; 1%).

^cOther reasons included pregnant/lactating women (n = 3; 0.5%) and unable to provide informed consent in English or French (n = 2; 0.3%)

^dIncludes all participants. Participants were analyzed according to the group to which they were randomized. Participants who were lost to follow-up or withdrew were assumed to have returned to smoking at their baseline level.

^eFor participants who were lost to follow-up, vital status was obtained if possible from medical record review or alternate contact.