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E-cigarette use doubles heart attack risk
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Daily use of electronic cigarettes doubled a person’s risk for heart attack, according to an analysis of survey data collected by CDC.
Dual daily use of e-cigarettes and conventional cigarettes appeared associated with a nearly fivefold elevated risk, results showed.
“Most adults who use e-cigarettes continue to smoke [traditional] cigarettes,” Stanton Glantz, PhD, professor of medicine at University of California, San Francisco, and director of USCSF Center for Tobacco Control Research and Education, said in a press release. “[Although] people may think they are reducing their health risks, we found that the heart attack risk of e-cigarettes adds to the risk of smoking cigarettes. Using both products at the same time is worse than using either one separately. Someone who continues to smoke daily while using e-cigarettes daily increases the odds of a heart attack by a factor of five.”
Glantz and colleagues analyzed data from 69,725 people who underwent in-person interviews as part of the National Health Interview Surveys in 2014 and 2016. Participants characterized their use of traditional or e-cigarettes by choosing one of four options: never, former, some days or daily.
Respondents also indicated whether they had been told by a physician or other health professional that they had experienced a heart attack.
Researchers evaluated responses in a single logistic regression model that accounted for age, sex, BMI and health characteristics, such as diabetes, hypertension and hypercholesterolemia.
Approximately one in seven respondents (13.4%; n = 9,352) identified themselves as current or former e-cigarette users. Of this group, 333 (3.6%) respondents reported they had experienced a heart attack, with daily e-cigarette users demonstrating the highest risk (6.1%).
Daily e-cigarette use appeared independently associated with elevated risk for heart attack (OR = 1.79; 95% CI, 1.2-2.66), as did daily conventional cigarette use (OR = 2.72; 95% CI, 2.29-3.24).
Two-thirds (66%) of the current e-cigarette users in the analysis also identified themselves as current cigarette smokers. Survey respondents who reported daily dual use of both products appeared 4.6 times as likely to have a heart attack than those who never used either product.
HemOnc Today spoke with Glantz about the study and the potential implications of the results.
Question: What prompted you to conduct this study?
Answer: E-cigarettes are widely used and promoted as being safer than [traditional] cigarettes, or at least ‘virtually safe.’ I have done a lot of other work showing that inhaling low doses of cigarette smoke increases the risk for heart attacks, and those effects occur quickly. This was a logical question to ask.
Q: How did you conduct the study?
A: The data came from the National Health Interview Survey, conducted by the CDC every year. We examined two years’ worth of data from the publicly available data sets. This represented 70,000 people.
Q: Can you elaborate on the key findings?
A: E-cigarettes are an independent risk factor for heart attacks in addition to any smoking that the user engages in. Dual use — meaning someone continues to smoke cigarettes while using e-cigarettes, which is the most common use pattern for e-cigarettes — increases risk compared with traditional smoking alone. Even someone who transitions completely from cigarettes to e-cigarettes does not derive much health benefit in terms of reducing heart attack risk.
Q: Did the findings surprise you?
A: I was surprised at the magnitude of the effect. Most people — including me — have thought e-cigarettes were kind of like cigarettes, but without quite as many harmful substances in them. We assumed someone who simply added a few e-cigarettes or substituted a few e-cigarettes for traditional cigarettes wouldn’t experience much effect. It turns out that e-cigarettes pose an independent risk for heart attack that is different than cigarettes. Some of the mechanisms by which they act are common, but they are independent effects. E-cigarettes really are a different kind of toxic exposure.
There are three prime motivations for e-cigarette use: People think they are safer, they believe they can use them in places where they are not allowed to smoke, and they want to use them to quite smoking. All three of those beliefs are wrong. E-cigarettes don’t help people quit smoking; they make it harder to quit. There also is an increasing number of places — for example, the entire state of California — where e-cigarettes are illegal in the same places where it is illegal to smoke cigarettes.
Q: What are the potential explanations for the elevated heart attack risk among daily e-cigarette users?
A: The primary causative agent may be the ultrafine particles in e-cigarettes. With cigarettes, you set the tobacco on fire to generate an aerosol of ultrafine particles, and that carries the nicotine deep into your lungs. An e-cigarette does that by heating a liquid solution of nicotine to generate the aerosol. There aerosol is still there, and those ultrafine particles have serious negative short-term and long-term effects on cardiovascular function. In addition, the nicotine changes the state of your unconscious nervous system in ways that, over the long term, are associated with heart disease risk. There are many strong oxidizing chemicals in e-cigarettes — such as acrolein — that are associated with heart disease risk. These effects occur within minutes. It is different from cancer, where the effect takes many years to manifest.
Q: Many oncologists tell their patients to quit smoking, but they may compromise with reluctant patients by encouraging them to transition to e-cigarettes under the presumption it will improve cancer outcomes and reduce risk for second malignancy. How do your findings fit into these conversations?
A: A few people do successfully quit smoking with e-cigarettes, but the vast majority of smokers who also use e-cigarettes have a harder time quitting. Advising people who have cancer and are smoking to try e-cigarettes is to advise something that actually reduces the likelihood that people will quit smoking. Beyond that, recommending e-cigarettes is dangerous to patients. E-cigarettes deliver a lower level of cancer-causing chemicals than traditional cigarettes, but these cardiovascular effects are very serious. Also, although nobody has explicitly studied it, exposure to nicotine— even in e-cigarettes — makes cancer worse. Although nicotine does not cause cancer, it aggravates cancer by promoting growth of the blood vessels into tumors, as well as other changes that make tumors grow faster. Neither, oncologists nor any other physician should recommend e-cigarettes for smokers. There are many proven strategies — such as nicotine replacement therapy or prescription drugs — that, if administered properly and combined with counseling, work quite well. If a patient is already using e-cigarettes and does not want to change, at the very least they need to be told they have to stop dual use with cigarettes. – by Scott Buzby
Reference:
Alzahrani T, et al. Am J Prev Med. 2018;doi:10.1016/j.amepre.2018.05.004.
For more information:
Stanton Glantz, PhD, can be reached at stanton.glantz@ucsf.edu.
Disclosure: The study was funded by NIH and FDA. Glantz reports no relevant financial disclosures.