Both smoking and vaping harden arteries and increase risk of heart, lung damage, says study
The use of e-cigarettes and waterpipes (often referred to as shisha, hookah, narghile) is an emerging trend, especially among younger generations. Researchers now warn that smoking and vaping, whether using tobacco cigarettes, e-cigarettes or waterpipes, stiffens the arteries, causes inflammation and damages DNA, leading to a variety of health problems.
The research team also found that smoking and vaping may increase the risk of people infected with Covid-19 suffering worse symptoms, and dying from it. "As outlined by the World Health Organization (WHO), tobacco cigarette and waterpipe smoking may contribute to an increased burden of symptoms due to Covid-19 compared to non-smoking, including being admitted to intensive care, requiring mechanical ventilation, and suffering severe health consequences," write authors in the study published in the European Heart Journal.
They add, "Since smoking per se is a well-established risk factor for respiratory infections and increases the probability of having pre-existing conditions such as cardiovascular disease, it could make Covid-19 patients more susceptible to severe symptoms, thus leading to increased mortality." The team includes experts from the University Medical Center of the Johannes Gutenberg-University Mainz, Germany, University of Massachusetts Medical School, US, and University College London.
They compared the effects of the three forms of smoking and vaping on human health and the function of cells that line blood vessels (the endothelium). It provides an overview of the available evidence about the harmful chemicals produced and the mechanisms by which smoking and vaping affect the body. The researchers also looked at the effects of each on medical conditions, ranging from stroke to heart attacks and lung cancer.
“The number of e-cigarette and waterpipe users has dramatically increased, with e-cigarettes being the most commonly used smoking products in 2014 in the US (more than 9- fold increase in usage from 2011 to 2015) and a projected global sales volume of $26.84 billion by 2023. Also, the prevalence of lifetime waterpipe use is of concern, ranging from 2.1% to 44.0% in the US, 11.6% to 40.1% in the UK, and 20.0% to 28.9% in Germany," says the study.
The review graded studies as providing strong, good, or medium levels of evidence on the harmfulness of the three types of smoking and vaping. They found multiple good studies were showing that, overall, tobacco cigarettes were more harmful than e-cigarettes. However, there were few good, large studies about the adverse effects of waterpipes and e-cigarettes on endothelial dysfunction and so the evidence was more variable. The research team says that more studies are needed to understand the long-term effects of water pipes and e-cigarettes.
They, however, write that waterpipe smoking is not less harmful than tobacco smoking and thus cannot be considered a healthy alternative. "The greater smoke volumes expelled from waterpipe sessions may lead to even higher exposure to toxicants as compared to tobacco cigarette smoking. In general, the increased use of e-cigarettes and waterpipe is concerning," says the team.
According to the analysis, compared to non-smokers, tobacco cigarettes increased the risk of chronic obstructive pulmonary disease (COPD) by 704% (good level of evidence), waterpipes by 218% (strong) and e-cigarettes by 194% (good); tobacco cigarettes and waterpipes increased the risk of lung cancer by 1,210% (strong) and 122% (strong) respectively. The level of evidence for e-cigarettes was not sufficient to draw reliable conclusions.
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The team also analyzed how much the three smoking techniques stiffened the arteries, an important prognostic 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% (medium level of evidence for all three). “All three forms of smoking and vaping lead to increased production of oxygen-derived free radicals in blood vessel tissue, such as superoxide. This breaks down nitric oxide, which is released by the endothelium, and is important for helping blood vessels to dilate and for protecting against inflammation and clogging of the arteries," says first author, Professor Thomas Münzel, Department of Cardiology at the University Medical Centre Mainz in Mainz.
Researchers say the main toxic chemicals in e-cigarette vapor include formaldehyde and acrolein, as well as traces of chemicals called transition metals and volatile organic compounds (VOCs), all of which are known to damage cells. In contrast, tobacco cigarettes and waterpipe smoke contain a much more complex mixture of harmful chemicals and other substances. Waterpipe smoke contains solid particulate matter, originating mainly from the charcoal used to burn the tobacco; this is also present in lower concentrations in cigarette smoke.
Nicotine is present in all three tobacco products, is addictive, and is responsible for harmful biological effects as well as, to a minor extent, some beneficial effects, they say. "These different, as well as overlapping profiles of toxic compounds, may be a key to understanding the similarities and differences in the adverse health effects of smoking and vaping, and should be further investigated in detail by future studies," says Professor Münzel.
Based on their findings, the experts conclude that "there is no doubt that smoking cessation is and will remain the most powerful approach" to prevent smoking-induced cardiovascular and respiratory disease. "This may be even more important in light of the Covid-19 pandemic as the use of tobacco products likely increases the risk for Covid-19 associated cardiovascular and other severe complications in smokers and vapers," cautions the team.