Table 1.

Electronic nicotine delivery systems systematic review study categories and outcomes

Study category	Outcomes
Product features	Product design Nicotine, propylene glycol, flavouring, particulate matter and other toxicant content
Health effects	Effects of: Nicotine Tobacco-related toxicants Non-tobacco-specific toxicants Impact on: Cardiovascular system Lung function Blood count Other physiology Cognition Abuse liability/addictiveness Adverse events Cytotoxicity
Consumer perceptions	Awareness Product perceptions Interest Reasons for use
Patterns of use	Ever, current and dual use with other tobacco products Initiation/progression Smoking cessation/reduction Use among various groups: general population, youth, young adults, adults, current smokers, former smokers, never-smokers, etc
Marketing	Advertisement/promotion prevalence and expenditure Claims and depictions Receptivity to advertising/promotion Marketing channels
Sales	Market share/sales volume Retail and online availability Pricing
Policies	Federal, state, local and organisational Existing and proposed Public support for policy