Heavy smokers who use both cigarettes and e-cigarettes are at greater risk of stroke, say researchers. At the same time, the same study shows that e-cigs alone do not increase the risk of stroke at all. The US study is now being criticized for being misleading.
The study, published in American Journal of preventive medicine, is an analysis of 160,000 Americans' self-reported health status with a focus on smokers and vejpers. The age range is 18 to 44 years and the data is collected between the years 2016 and 2017.
The results showed that smokers and those who used to smoke and now vejp are at essentially the same risk of stroke. For the group using both e-cigs and analog cigarettes, the risk was even higher.
"Our analysis indicates that the claimed benefits of e-cigarettes over smoking are not clear," the researchers write.
However, the analysis is criticized because the risk of stroke was assessed based on reported cases, without taking into account when the person in question had their heart attack: it may well have occurred before the person started using e-cigarettes. This is also something that the researchers point out.
"The results should be interpreted with caution. We have not been able to see the timeline between smoking and e-cigarette use," the researchers write.
Wrong conclusions
According to several leading researchers in the field of e-cigarettes and health, the current study is grossly misleading. In particular, the authors claim, among other things, that dual use (e-cigs + analog cigs) is more risky than just smoking traditional cigarettes. The authors also write that the flavors in the e-liquid may be the reason for the increased risk.
"Such a claim is grossly contradictory. Their results clearly show that e-cigarettes alone do not lead to increased risk" says Dr. Lion Shahab, epidemiologist and public health researcher at the University of London to the Science Media Center.
He believes that the potentially higher risk of dual use is more likely to be due to the fact that heavy smokers who are already at risk are also part of the group that most often uses e-cigarettes to try to cut down on smoking.
"We know from previous studies that this particular group is at increased risk from the outset, as they have consumed more harmful substances through smoking over a long period of time than others. They also have a greater need for nicotine, which explains the dual use", says Lion Shahab to Science Media Center.
Stroke leads to vejpning
Lion Shahab is joined in his criticism by John Britton, Professor and Director of Tobacco and Alcohol studies in London.
"This study shows that there is a link between smoking and stroke. This is well known and a completely expected result. It also shows that vejpning itself does not increase the risk of stroke. This contradicts their entire reasoning. However, we see a clear pattern of reverse correlation - those smokers who have had a stroke or feel the health effects of smoking are also those who try to quit smoking. This study is absolutely no evidence that e-cigarettes increase the risk of stroke in ex-smokers." says John Britton to Science Media Center.
Long time for vessels to heal
Previous research has shown that the risk of heart disease decreases immediately when someone quits smoking, regardless of whether they use e-cigarettes or other nicotine products. This became clear when researchers studying similar statistical evidence also took into account the time elapsed after quitting smoking in relation to e-cigarette use and the timing of reported heart disease such as stroke.
"It takes a long time to get rid of the harmful effects of smoking. It is only after six years that we can expect the risk of heart disease to be at the same level as for a non-smoker. And for e-cigarette users, that risk is the same as for a non-smoker, six years after quitting," said the cardiologist Konstantinos Farsalinos who led the study.
Vejpare got better blood vessels
Similar conclusions were also drawn by British researchers in the fall of 2020. controlled long-term study found that ex-smokers who switch completely to e-cigarettes have better blood vessels within a month. The study was the first of its kind. It involved 114 smokers. All had smoked at least 15 cigarettes a day for at least two years before the study. They were randomly divided into three groups: one group continued to smoke, two groups switched from cigarettes to e-cigarettes, one with nicotine and the other without.
The study showed that the ability of the vessels to contract had increased significantly for the group using e-cigarettes instead of cigarettes, already after one month. Along with measurements of vessel stiffness, participants who vejped showed clear signs of improved vascular health compared to the group who still smoked.
