Table 1.

Population, intervention, comparator and outcome inclusion criteria for review question

Element	Description
Population	Adolescents who never smoked tobacco cigarettes at baseline. The age of the included population was between 13 and 19 years at baseline. The could be living in any country around the Globe.
Exposure	Any e-cigarette vaping at baseline or in the past
Comparators	Non-electronic cigarette user
Outcomes	Initiation of tobacco cigarette smoking at follow-up
Study design	Longitudinal cohort studies
Search dates	2005–2019