EXPERT ANALYSIS FROM TERATOLOGY SOCIETY 2017
DENVER (FRONTLINE MEDICAL NEWS) – Can e-cigarettes help smokers quit?
“So far, the evidence regarding e-cigarettes’ effectiveness for smoking cessation is equivocal at best,” Alison Breland, PhD, said at the annual meeting of the Teratology Society.
But Dr. Breland noted that there is significant controversy around this topic. “I can tell you that, at the conferences I go to, where there are lots of people studying nicotine and tobacco, scientists are fighting with each other over this question,” said Dr. Breland , a psychologist and project director at the Center for the Study of Tobacco Products at Virginia Commonwealth University in Richmond.
Several small, randomized, controlled trials suggest electronic cigarettes have efficacy comparable to the nicotine patch. But the bulk of the literature indicates otherwise. Dr. Breland found persuasive a systematic review and meta-analysis of 38 studies: Its investigators at the University of California, San Francisco, concluded that the odds of quitting smoking were 28% lower in smokers using e-cigarettes, compared with those not using the devices ( Lancet Respir Med. 2016 Feb;4[2]:116-28 ).
That being said, she noted that this meta-analysis has generated unusually harsh printed comments from its critics.
“We could argue about the methodology of the studies all day. If you think all the studies are garbage then you won’t believe the odds ratio, either. But I think right now the evidence shows that e-cigarettes don’t seem to help people quit,” she said. “That may change in the future with testing of different kinds of devices.”
To be useful for smoking cessation, she explained, a device would need to consistently deliver enough nicotine to enable the smoker to fend off withdrawal symptoms but not so much that the wish to quit evaporates. It’s a matter of finding the sweet spot in what is technically termed device nicotine flux.
There is a great deal of misconception about e-cigarettes, Dr. Breland said, some of it promoted through misleading product advertising. She sought to set the record straight.
How e-cigarettes work
What are e-cigarettes? They are basically nicotine delivery devices. They use electricity to power a heating element that aerosolizes a liquid containing varying concentrations of nicotine; solvents, such as propylene glycol and vegetable glycerins; and flavorants. As a class, e-cigarettes are rapidly evolving. A vast array of devices are marketed with wide differences in design, materials, construction, amount of nicotine delivered, and electrical power – which, along with puff duration, is a key factor in how much nicotine gets into a user’s blood.
“Most of the devices have a battery, but it’s important to know that some of them can be plugged directly into a USB port on a computer,” Dr. Breland said.
E-cigarettes don’t generate a vapor, as is widely believed. It’s an aerosol, and it contains toxic byproducts. On the plus side, unlike combustible cigarettes, e-cigarettes don’t deliver carbon monoxide.
A vast array of flavorant mixtures are sold, including some that are clearly designed to be attractive to children, with names like “blue cotton candy” and “Apple Jacks.”
User demographics
Who is using e-cigarettes? Primarily adolescents and young adults in prime reproductive age. National surveys indicate e-cigarettes are now the most widely used tobacco product among U.S. high school students, well ahead of combustible cigarettes.
Of particular concern, data from the Centers for Disease Control and Prevention’s National Health Interview Survey indicate that, among 18- to 24-year-olds who use e-cigarettes, about 40% also currently use conventional cigarettes, about 20% are former cigarette smokers, and about 40% are never smokers – that is, have never smoked combustible cigarettes (MMWR Morb Mortal Wkly Rep. 2016;65:1177. doi: 10.15585/mmwr.mm6542a7 ).
“We don’t know what’s going to happen to these never smokers who are currently using e-cigarettes. Are they starting on a lifetime of nicotine dependence via e-cigarettes, or perhaps even worse, are they going to transition to combustible cigarettes? There’s more and more evidence showing that’s happening,” Dr. Breland said.
The CDC survey also showed that 59% of adult users of e-cigarettes are what Dr. Breland called “dualies,” individuals who also smoke conventional cigarettes.
“That really diminishes any potential benefit of e-cigarettes,” she said.
Impact on pregnancy
What is known about the impact of e-cigarettes on pregnancy and birth outcomes? Almost nothing at this point. E-cigarettes deliver nicotine to the bloodstream, and nicotine is known to cause unwelcome, long-term changes in fetal brain development and in that of adolescents as well. The other aerosolized toxicants have not been well studied. A few small surveys conducted in obstetric practices indicate some pregnant women perceive e-cigarettes as posing only minor health risks and safer than combustible cigarettes. And some pregnant women are using e-cigarettes.
Dr. Breland is an investigator in an ongoing, multicenter, longitudinal study enrolling pregnant smokers during their first trimester and following them through childbirth. So far, the investigators have enrolled 93 conventional cigarette users and 24 dualies but have managed to enroll only three exclusive e-cigarette users.
“I think it’s notable that we’re not finding exclusive e-cigarette users. It’s early in the study, but so far the dual users are smoking the same number of cigarettes per day as cigarette-only users, and they have the same expired carbon monoxide levels. It makes me feel concerned in particular about dual use in pregnancy,” she said.
Regulation
One audience member asked what the point of allowing e-cigarettes is since, under a best-case scenario, their effectiveness as a smoking cessation tool is similar to a nicotine patch, and smokers already have access to the patch as well as nicotine gum.
Dr. Breland replied that the patch and gum deliver nicotine very slowly, so they are not as satisfying as smoking.
“The hope with e-cigarettes is that, since they get nicotine into your blood pretty fast – similar to a cigarette – they can more effectively suppress your withdrawal,” she said. “Whether or not that’s true isn’t known yet.”
The Food and Drug Administration has the authority to regulate e-cigarettes through several different mechanisms but, in late July 2017, announced a delay in issuing new regulations that would likely have removed many of the devices and flavorings from the marketplace.
Dr. Breland’s research is supported by the National Institute on Drug Abuse and the Food and Drug Administration. She reported having no financial conflicts of interest.
