By: Bradley J. Fikes
Smokers who switch to e-cigarettes greatly reduce their exposure to carcinogens and other toxic inhaled substances, according to a British study released Monday.
The study of 181 smokers and former smokers was the first to directly measure and compare levels of these substances in people, its authors said. The harm reduction depends on a total substitution of e-cigarettes for smoking, the study stated.
Previous studies have been performed on cell cultures or animals, or measured substance levels in e-cigarette vapor. While these proxy measurements are useful, direct measurements in people provide superior knowledge of the risks incurred.
Researchers analyzed the saliva and urine of long-term smokers, as well as that of e-cigarette users, called vapers, and users of nicotine replacement therapies, or NRTs. They measured levels of TSNAs (tobacco-specific nitrosamines) and VOCs (volatile organic compounds), established risk factors for smoking-related diseases.
The study was published in the Annals of Internal Medicine. It can be found at j.mp/ecigrisk.
Four other researchers who didn’t take part in the study said it added to evidence that e-cigarettes are less harmful than smoking. But they differed on its significance.
American public health organizations have generally opposed vaping, even as an aid to quitting smoking. They say evidence is lacking that e-cigarettes are effective, and endorse alternative methods of quitting, such as nicotine patches or gum. And they say non-smokers may take up vaping under the mistaken belief that it’s harmless.
Meanwhile, the U.S. Food and Drug Administration is imposing strict new rules on e-cigarettes, classifying them as tobacco products. The e-cigarette liquids vaporized contain no tobacco. The e-cigarette industry says these rules would add so much expense that smaller makers would fold, leaving the market to the big vendors, who happen to be tobacco companies.
But British public health agencies have generally endorsed e-cigarettes as being far less risky than conventional cigarettes, and useful for smokers trying to quit. They embrace an approach called harm reduction that endorses lessening risk. Since there is widespread agreement that e-cigarette “vaping” poses less of a risk than smoking, they say smokers should be encouraged to try vaping.
Last spring, the Royal College of Physicians approved vaping for smokers, saying that e-cigarettes have been shown to be effective for smoking cessation.
Where danger lies
While nicotine is the addictive drug in cigarettes, it’s not the most harmful one. Researchers are even studying the use of nicotine to help against certain neurodegenerative illneses, such as Alzheimer’s and Parkinson’s diseases.
The real danger of cigarettes lies in the other substances carried in smoke, include those produced by combustion. The threats include lung diseases, including cancer, and cardiovascular disease. The study paid particular attention to the risk for cancer.
The level of dangerous chemicals found in solo e-cigarette users was found to be a fraction of that in solo smokers of regular cigarettes, expressed in percentages.
— 2.5 percent the level of TSNAs
— 33.3 percent for acrolein
— 42.9 percent for acrylamide
— 2.9 percent for acrylonitrile
— 11.0 percent for 1,3-butadiene
— 43.5 percent of ethylene oxide, acrylonitrile and vinyl chloride.
But e-cigarette users were found to have 126.9 percent of nicotine or equivalent of smokers.
These numbers were reported at a 95 percent confidence level.
The four researchers interviewed for this article agreed that e-cigarettes are less hazardous than smoking. But they disagreed on the study’s significance.
Useful, but limited
David W. Bareham, a specialist respiratory physiotherapist in England, cautiously endorsed the study, while emphasizing that it has limitations.
The study indicates that a total switch from cigarettes to vaping should significantly reduce the risk from cancer, all else being equal, said Bareham, of Lincolnshire Community Health Services near Nottingham, England.
But the study’s findings related to cancer don’t address other potential harms from e-cigarette use, Bareham said by email. Moreover, more work is needed to reduce potentially harmful chemicals in e-cigarette vapors.
“This new study under review here, though helpful, is only part of the puzzle that is e-cigarettes,” Bareham said.
“Further, long term studies, following e-cigarette users for a prolonged period of time, tracking not just issues mostly related to cancer, but other specific respiratory and cardiac risks, are still required, before anyone can confidently claim that the harmful effects of switching purely to e-cigarettes are ‘minimal’ . . . .”
“CDC data demonstrates, importantly, that basically as many people die from the cardiovascular effects of smoking tobacco as from cancer effects, so, if we then add on the premature deaths of the non-cancer lung disease, it becomes clear that the health effects of smoking are much more than those purely related to cancer,” Bareham said.
Dr. Michael Siegel, a tobacco control specialist at Boston University who supports e-cigarettes for smoking cessation, was enthusiastic about the findings.
“This study adds to the abundant evidence that e-cigarettes are much safer than real tobacco cigarettes,” Siegel said by email. “In fact, for the four carcinogens and two toxins tested, levels in e-cigarette users were comparable to those in nicotine patch users and much lower than in cigarette smokers. The study also showed that dual use of cigarettes and e-cigarettes did not significantly reduce exposure to these 6 chemicals.”
Siegel said the study “suggests that benefits in terms of cardiovascular disease and cancer will only occur if a smoker switches to vaping completely.”
“The bottom line of this study is that there is now no scientific uncertainty: vaping is much safer than smoking,” Siegel said.
The study also breaks new ground by measuring levels of dangerous chemicals directly from people, Siegel said.
Laura Crotty Alexander, M.D. a UC San Diego researcher and pulmonologist, said by email that the study is “a nice addition” to existing research.
“These data are reassuring in that e-cigarette users have lower urine levels of nitrosamines and volatile organic compounds (VOCs), which are two types of chemicals that are found in the urine of conventional tobacco smokers, and contribute to the development of tobacco related diseases,” Crotty Alexander said. “Thus, these data suggest that e-cigarettes are far less dangerous than smoking conventional cigarettes.”
Crotty Alexander said caution is still needed, because the long-term health effects of regular e-cigarette use have yet to be determined.
“These researchers were specifically looking at levels of chemicals known to be a problem in tobacco smoking, which is an excellent starting point for evaluating the safety of e-cigarettes,” she said. “However e-cigarette vapor is very different than tobacco smoke, and thus effects on human health may not mirror those seen with tobacco use.”
UCSD researcher Wael Al-Delaimy, M.D., said by email that the study didn’t find anything significantly new.
“We all know that using only e-cigarettes is less harmful than using combustion cigarettes for the simple reason that combustion of tobacco is what produces the carcinogens,” said Al-Delaimy, UCSD’s division chief of global health in the department of family medicine and public health.
E-cigarettes have been documented to produce close to 50 percent of the harm from regular cigarettes, he said, because of the effect on the cardiovascular and respiratory systems.
“The authors just brushed aside that impact and focused on the lower carcinogens from tobacco,” Al-Delaimy said. “Nevertheless if a smoker has a choice between smoking a cigarette or an e-cigarette, of course it is better to use e-cigarettes as the less harmful choice.”
Al-Delaimy said he was especially concerned that smokers generally don’t find e-cigarettes helpful in quitting, especially in the United States.
“Further, there is clear evidence that non-smokers are starting e-cigarettes (especially young adults and teens) because of the publicity and novelty of e-cigarettes. The paper does not address nonsmokers who use e-cigarettes compared to nonsmokers who do not use any e-cigarettes to see the chemicals they are being exposed to (other than the carcinogens, such as flavoring chemicals).
“More importantly, the paper shows that those who use both combustion cigarettes and e-cigarettes actually have higher levels of these carcinogens which is counter to the belief of the e-cigarette and vaping advocates that using e-cigarettes will help cut down combustion cigarette use. It is indicating the opposite, and this is consistent with studies we have published and others, that using e-cigarettes is making it more difficult for smokers to quit. The authors don’t point to this problem and try to justify it otherwise.
“In this paper the former smokers who now use only e-cigarettes is a positive outcome, but what is their proportion in the real world of smokers? Not a substantial one I am afraid,” Al-Delaimy said.