Both smoking and vaping can stiffen the arteries and increase the risk of developing adverse lung conditions, scientists have said.
Their findings are based on a clinical review of the available evidence gathered from multiple studies.
An analysis by an international team of researchers found that tobacco cigarettes, in general, were more harmful than electronic cigarettes.
The team also said that waterpipe smoking, which involves passing smoke through water before inhaling, is as damaging as tobacco smoking and hence, “cannot be considered a healthy alternative”.
They added that both smoking and vaping may increase the risk of people developing severe Covid-19 symptoms.
Based on their findings published in the European Heart Journal, the scientists are urging people to try to give up smoking, regardless of which method they use.
But experts argue that the review does not provide clarity on whether the harmful effects seen in e-cigarette smokers come from prior tobacco cigarette use, saying most e-cigarette users were former tobacco smokers.
The researchers looked at the effects of each on medical conditions, including lung cancer and chronic obstructive pulmonary disease (COPD).
Compared to non-smokers, the use of tobacco cigarettes, waterpipes, and e-cigarettes were found to increase the risk of COPD.
Tobacco cigarettes and waterpipes also increased the risk of lung cancer but the researchers said there was not enough evidence to assess the risk of e-cigarettes on the disease.
The team also looked at how much the three smoking techniques stiffened the arteries, an important indicator for the risk of heart problems and stroke.
Compared to non-smokers, tobacco cigarettes increased arterial stiffness by 10%, waterpipes by 9%, and e-cigarettes by 7%, the researchers said.
Professor Thomas Munzel, of the department of cardiology of the University Medical Centre Mainz in Germany, who is first author on the study, said: “The WHO [World Health Organisation] also warns that although e-cigarettes appear to be less harmful than tobacco cigarettes, there is growing evidence that they also may cause side effects in the lungs, heart and blood vessels and that e-cigarette use may increase the risk of Covid-19 infection.”
Commenting on the study, Jacob George, a professor of cardiovascular medicine and therapeutics at the University of Dundee, who was not involved in the research, said: “What we cannot say for certain, and the study does not provide further clarity on either, is how much of the effects seen in e-cigarette smokers are due to prior tobacco cigarette use.
“No study so far has accurately and absolutely quantified prior impact of tobacco cigarette smoking on vascular dysfunction in individual e-cigarette users as we know that most e-cigarette smokers are former users of tobacco cigarettes and a number are dual users also.
“Disentangling this from the distinctive impact of e-cigarettes on vascular function is still required to fully understand the risks versus the benefits of e-cigarettes, which on a comparative basis contains significantly fewer than the 7,000 harmful chemicals present in every tobacco cigarette that is smoked.”
Meanwhile, Dr Nick Hopkinson, reader in respiratory medicine at Imperial College London, who was also not involved in the study, added that people who need to use a substitute source of nicotine, such as an e-cigarette, to quit the habit may have smoked more intensely than those who were able to quit without using an aid, which makes comparisons difficult.
He said: “It is important to note that the best evidence around vaping and blood vessel function is that in people who switch from smoking to vaping there is a substantial improvement in endothelial function.
“No serious commentator claims that vaping is completely harmless, but the hazard compared to smoking is much lower.”