Frontiers Direct health implications of e cigarette use: a systematic scoping review with evidence assessment E cigarettes: Facts, stats and regulations The Demographics of E Cigarette Users [Part 1 of 3 Part Series] Canada Gazette, Part 1, Volume 154, Number 51: E cigarettes and health here's what the evidence actually says Vox Estimation of the global number of e cigarette users in 2020 Harm Reduction Journal Springer Nature Link