Albert Rizzo, Chief Medical Officer of the American Lung Association explained
Vaping: Better or Worse Than Cigarettes
However, it can take decades of follow-up and complex study designs for such increased risk to show up in the data

Dr Sharon Cox, a research fellow in Behavioural Science and Health at University College London, said in response to the ASH study, The evidence on vaping for smoking cessation is clear and strong, it is far safer to switch to vaping nicotine than it is to continue smoking combustible tobacco it is the poor reporting of studies, as well as poorly conducted studies, which has led to widespread misperceptions. Another research fellow, Dr Sarah Jackson, from the University College London Tobacco and Alcohol research group added, There is an ongoing disconnect between scientific evidence on the relative harms of vaping compared with smoking and how these risks are communicated to the public media coverage typically focuses on risks to young people who dont smoke and generally doesnt compare these to any risks vapers would face if they opted to smoke instead. THE TRUTH ABOUT VAPING There is scaremongering here in the UK as well, taking the shape of looking at E-Cigarettes without the context of smoking

[11] Diacetyl is now found to be added to several e-liquids to enhance sweet flavors