August 24, 2018

expert reaction to e-cigarettes and risk of heart attacks

Researchers, publishing in American Journal of Preventive Medicine, reported that use of e-cigarettes every day there was a associated with a higher risk of heart attacks.

Prof Peter Hajek, Director of the Tobacco Dependence Research Unit, QMUL, said:

“This is based on data showing that smokers who have had an MI are more likely to switch to vaping. This is first presented as an association between vaping and myocardial infarction – and then twisted further to ‘E-cigarette use is associated with increased risk of myocardial infarction’.”

Dr Lion Shahab, Associate Professor of Health Psychology, UCL, said:

“This interpretation of findings in this paper is seriously flawed for two main reasons.

“First, as this is a cross-sectional study, the analysis cannot distinguish what occurred first – the switch to dual use of e-cigarettes or the heart attack. An alternative, probable explanation for these results is that smokers who experience a cardiovascular event maybe more likely to reduce their cigarette consumption and try to stop smoking, as has been reported in the literature. One way of achieving smoking reduction is to use e-cigarettes. Thus, rather than a cause of heart attacks, dual use maybe a consequence of them. This type of study cannot establish the sequence of events and therefore needs to be interpreted cautiously.

“Second, and equally problematic, is the fact that in observational studies such as this, confounding cannot be excluded. It is well known that smoking increases the risk of cardiovascular events and that this is related to both length of smoking and intensity of smoking. The kind of effect observed here for dual users is unlikely to be driven by e-cigarette use, given that most e-cigarette users had been long-term past or current cigarette smokers. It is unclear how relatively short-term e-cigarette use could lead to the same health effect as decade-long smoking of cigarettes.

“A better and more appropriate way of investigating whether e-cigarette use increases the risk of heart attacks would be to follow e-cigarette users who have never smoked long-term to establish both the sequence of events and whether there is a risk, independent of current or past cigarette smoking. Unfortunately, this was not done here and the interpretation presented goes clearly beyond what can actually be concluded from the study results.”

* ‘Association Between Electronic Cigarette Use and Myocardial Infarction’ by Alzahrani et al. was published in American Journal of Preventive Medicine on August 22^nd 2018. 

Declared interests

None received.

Researchers, publishing in American Journal of Preventive Medicine, reported that use of e-cigarettes every day there was a associated with a higher risk of heart attacks.