Harms and benefits of e-cigarettes and heat-not-burn tobacco products. A literature map

This mapping exercise describes the nature and extent of the peer-reviewed literature on the public health harms and benefits of e-cigarettes and heat-not-burn tobacco products to the human population. The authors identified 388 papers eligible for inclusion in the map, 361 reporting the harms and benefits of e-cigarettes, and 28 reporting the harms and benefits of heat-not-burn tobacco.

Most of the observed harms were due to acute events associated with the use of e-cigarettes. They included poisonings, burns, fractures, lung injury and exacerbations of asthma. There were fatalities among the poisonings and respiratory disease cases, and long-term disability among some burn cases. There was some early evidence of damage to cardiovascular and respiratory tissue, mainly due to metals and volatile organic compounds. Four cross-sectional surveys on cancers identified the presence of carcinogens for lung, oral, and oesophageal cancer, and one identified biomarkers for bladder cancers. Some respiratory, cardiovascular, and oral diseases were noted to be less harmful in e-cigarette users than in conventional cigarette smokers, but were as harmful in dual users.

The evidence map featured few reported benefits. The most common benefits, which were reported by a small number of heavy smokers of conventional tobacco cigarettes, were smoking cessation and smoking reduction. However, we note that many studies showed that dual use of both e-cigarettes and conventional tobacco cigarettes was not less harmful than smoking conventional tobacco cigarettes alone, thereby raising questions about the smoking reduction benefit of e-cigarettes.