Initiation behaviours | Baseline tobacco use group (W1 or W2) | Follow-up outcome (W2 or W3) |
Initiating ever use (online supplementary tables 2 and 3) | Never users*: never smoked/used the product/any tobacco product (even one or two times) | Initiating ever use: ever smoked/used the product/any tobacco product (even one or two times) |
Initiating P30D use (tables 2 and 3) | Never users as defined above | Initiating P30D use: smoked/used the product/any tobacco product in the P30D |
Initiating frequent use among those who initiated P30D use (results in-text only) | Never users who initiated P30D use at follow-up as defined above | Frequent use on initiation†: smoked/used the product on 20 or more of the past 30 days |
*Respondents who indicated ever use of a given tobacco product at a previous wave and never use of that same product at the current wave were coded as ‘ever’ users and excluded from the baseline sample. The percentage of those who met this definition at W2 ranged from 1.4% for hookah to 12.9% for electronic nicotine delivery systems.
†For any tobacco product use, frequent use on initiation was defined as having used at least one type of tobacco product on 20 or more of the past 30 days.
P30D, past 30 day; W1, Wave 1; W2, Wave 2; W3, Wave 3.