This is what makes the new report from the US National Academies of Sciences, Engineering, and Medicine based on the health effects of electronic cigarettes so significant. Based on more than 800 peer-reviewed scientific studies, David Eaton (chair of the committee that wrote the report) said “E-cigarettes cannot be simply categorised as either beneficial or harmful.”

A new study finds substantial evidence that e-cigarette use increases the risk of transitioning to smoking conventional cigarettes among youth

While e-cigarettes are not without health risks, evidence suggests they are likely to be far less harmful than conventional cigarettes, the study revealed. They contain fewer numbers and lower levels of toxic substances than conventional cigarettes, and using e-cigarettes may help adults who smoke conventional cigarettes quit smoking. However, their long-term health effects are not yet clear. Among youth – who use e-cigarettes at higher rates than adults do – there is substantial evidence that e-cigarette use increases the risk of transitioning to smoking conventional cigarettes.


Overall, e-cigarette aerosol contains fewer numbers and lower levels of toxicants than smoke from combustible tobacco cigarettes. Nicotine exposure can mimic that found with use of combustible tobacco cigarettes, but it is highly variable. The exposure to nicotine and toxicants from the aerosolisation of flavourings and humectants depends on device characteristics and how the device is used.


The evidence reviewed by the committee suggests e-cigarettes are not without biological effects in humans. For instance, use of e-cigarettes results in dependence on the devices, though with apparently less risk and severity than that of combustible tobacco cigarettes. Yet the implications for long-term effects on morbidity and mortality are not yet clear.


While e-cigarettes might cause youth who use them to transition to use of combustible tobacco products, evidence suggests they might also increase adult cessation of combustible tobacco cigarettes.

Completely substituting e-cigarettes for combustible tobacco cigarettes conclusively reduces a person’s exposure to many toxicants and carcinogens present in combustible tobacco cigarettes and may result in reduced adverse health outcomes in several organ systems. Across a range of studies and outcomes, e-cigarettes appear to pose less risk to an individual than combustible tobacco cigarettes.


There was no evidence whether or not e-cigarette use is associated with clinical cardiovascular outcomes, subclinical atherosclerosis, or intermediate cancer in humans. Similarly, there was no evidence whether e-cigarettes cause respiratory disease in humans or affect pregnancy outcomes.


Researchers stressed there is a great need for more and better evidence around the new field of e-cigarettes to help clarify whether e-cigarettes will prove to reduce or induce harm at the individual and population levels. Research with both long- and short-term horizons is required.

Until more definite scientific data are available, population modelling can help estimate the balance of potential benefits and harms.

Author: Nicky Belseck