We analyzed two tobacco use variables, which were assessed at baseline (age 14) and at follow-up (age 22). At age 14, a specific question about frequency of cigarette smoking was asked. Based on the responses, the adolescents were categorized into four groups: never, experimenting, occasional and daily cigarette smokers. For those reporting never use, confirmatory questions were asked, such as: “So, have you never tried any tobacco products, not even cigarettes?” Those who had smoked at least once, but less than 5 packs of cigarettes lifetime, were considered experimenters. Further, among those who had smoked at least 5 packs, those who reported smoking 3–4 days a week or less often, were categorized as occasional smokers, whereas those who smoked daily or almost daily were categorized as daily smokers.
