This report aims to provide a systematic overview of the contemporary evidence on the health effects of nicotine and non-nicotine e-cigarette use excluding, where possible, use of tetrahydrocannabinol (THC) and other illicit substances.

The primary health outcomes of interest include, but are not limited to: dependence; cardiovascular disease; cancer; respiratory disease; oral diseases; reproductive outcomes; injuries and poisonings; mental health conditions; and environmental hazards with human health implications. These findings are integrated with those from previous systematic reviews on smoking uptake and cessation.

There is strong or conclusive evidence that nicotine e-cigarettes can be harmful to health and uncertainty regarding their impacts on a range of important health and disease outcomes. Based on the current worldwide evidence, use of nicotine e-cigarettes increases the risk of a range of adverse health outcomes, including: poisoning; toxicity from inhalation (such as seizures); addiction; trauma and burns; lung injury; and smoking uptake, particularly in youth. 

Their effects on most other clinical outcomes are unknown, including those related to cardiovascular disease, cancer, respiratory conditions other than lung injury, mental health, development in children and adolescents, reproduction, sleep, wound healing, neurological conditions other than seizures, and endocrine, olfactory, optical, allergic and haematological conditions.