Millions of Life Years Saved if Smokers Switch to Vaping

Kristin Jenkins

October 05, 2017

Switching cigarette smokers to e-cigarettes, or "vaping," over a 10-year period could speed up the progress of tobacco control policies in the United States, preventing millions of premature deaths, and saving millions of life years, according to a new report.

Among the deaths are those from lung cancer, most of which is associated with smoking. In fact, smoking has caused an epidemic of lung cancer, according to Peter Boyle, Dsc(Med), PhD, president of the International Prevention Research Institute in Lyon, France. He noted that in 1912, lung cancer was described as one of the rarest tumor types. It has since become the most common cancer. Winning the war against smoking means winning the war against lung cancer, he said.

The new report projects mortality outcomes from current rates of cigarette smoking and compares them to two vaping substitution models ― one "optimistic," and the other "pessimistic" ― based on estimates of initiation, cessation, and known e-cigarette risk.

If switching to e-cigarettes reduced smoking prevalence to 5%, this would prevent 6.6 million premature deaths and save 86.7 million life years, say David T. Levy, PhD, of Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, in Washington, DC, and colleagues.

Younger smokers would benefit the most, with a 0.5 gain in average life expectancy projected for those aged 15 years in 2016, the study authors say in a report published online October 2 in Tobacco Control.

"Our analysis shows that a strategy of replacing cigarette by e-cigarette use can yield substantial gains, even with conservative assumptions about related risks," the study authors write.

Dr Levy and colleagues also comment that the role of e-cigarettes in tobacco control remains controversial. Divisions within the tobacco control industry on the use of modified risk products such as e-cigarettes have been fostered by the tobacco industry's strategies to "divide and conquer," they say. In the process, the tobacco control community "may have lost focus on cigarettes, the most deadly form of nicotine delivery."

In an interview, Dr Levy said e-cigarettes can provide a new smoking cessation method for smokers who have tried and failed to quit using traditional methods. "What we're seeing is a major reduction in smoking when people switch to e-cigarettes," he told Medscape Medical News. "The important thing is that they stop smoking cigarettes."

In the study, mortality associated with smoking was primarily due to cigarettes and cigars, including little cigars, and to a lesser extent, to smokeless tobacco, said Dr Levy.

Health gains would only be seen when smokers switch to e-cigarettes completely rather than smoking both, he emphasized, although there is usually a period of overlap as smokers transition to e-cigarettes. Early evidence also indicates that e-cigarettes are less addictive than combustible cigarettes and that it may be easier to quit smoking e-cigarettes than regular cigarettes.

Ultimately, a three-pronged approach consisting of traditional smoking cessation techniques, nicotine reduction in cigarettes, and encouraging the use of e-cigarettes instead of combustible tobacco products could be the best way to bring down smoking rates, Dr Levy said.

The analysis was confined to the US population aged 15 to 99 years in 2016 to reflect current smokers in a "status quo" scenario. Projections were then applied through the year 2100 to incorporate the potential health effects of who were younger.

In the pessimistic scenario, tobacco use is reduced to 10%, more young people are assumed to initiate e-cigarette and tobacco use, and the risks associated with e-cigarettes are regarded as more harmful than is suggested by current evidence. Even so, the investigators say, vaping instead of smoking could prevent 1.6 million premature deaths and save 20.8 million life years.

Endgame Scenario Within Reach?

The study authors point out that the 2014 Surgeon General's Report suggested that a new, fast strategy to end tobacco use is needed. Replacing cigarettes with e-cigarettes could meet this need as well as justify ramping up efforts to target cigarette smoking, as called for by the World Health Organization in July 2017.

"An endgame scenario for cigarettes might well be within reach, if new technologies for delivering nicotine with substantially less harm, but sufficient satisfaction, are harnessed with sufficient passion and political will to aggressively phase out tobacco cigarettes," Dr Levy and colleagues write.

An endgame scenario for cigarettes might well be within reach. Dr David Levy and colleagues

As previously reported by Medscape Medical News, the US Food and Drug Administration announced an overall plan in July 2017 to protect youth and reduce tobacco-related disease and death. Key tenets of the plan include lowering the nicotine content of cigarettes to levels below those known to be addictive and balancing regulation with the development of tobacco products less dangerous than cigarettes.

In an accompanying editorial, Marita Hefler, PhD, of the Menzies School of Health Research in Casuarina, Australia, agrees, pointing out that e-cigarettes and the newer heat-not-burn (HNB) tobacco products so closely mirror the smoking experience that they have "the greatest potential to displace combustible tobacco." The fact that combustible tobacco products are still widely available is "a historical anomaly," she adds, pointing out that "any other consumer product that kills up to two-thirds of its long-term users remaining legal is unimaginable."

Any other consumer product that kills up to two-thirds of its long-term users remaining legal is unimaginable. Dr Marita Hefler

The broad range of vaping products now on the market limits the findings of the current study, she says. However, it is this "new continuum of nicotine products" that could put an end to combustible tobacco and "allow the most dangerous end of the nicotine product continuum to be rapidly, and completely, phased out," Dr Hefler suggests.

Until such time, "prudent regulations" are needed as well as "substantial taxation" aimed at reducing the risk of nonsmokers being attracted to e-cigarettes, she says. The latter would also put the tobacco industry on notice for damages caused by its products.

"A higher tax on HNB would also recognize the culpability of the tobacco industry for the costs of smoking-attributable diseases, and preserve a significant revenue base to meet the ongoing costs of treating these diseases that will occur beyond a phase-out of combustibles, due to the lag in the decline of the disease burden after smoking prevalence has peaked," Dr Hefler writes.

When asked to comment, several independent experts said more study is needed before policy can be changed or clinicians can recommend that smokers switch to e-cigarettes instead of trying to quit using more traditional smoking cessation methods.

"The data were interesting and useful for our debate, but they don't provide enough evidence for health policy or for clinical recommendations," said Robert A. Schnoll, PhD, director of the Center for Interdisciplinary Research on Nicotine Addiction at the University of Pennsylvania, Philadelphia, in an interview. "We don't have a complete understanding of e-cigarettes, including the potential health risks and the potential long-term harms. I'm waiting for results from randomized controlled studies that meet the gold standard," he told Medscape Medical News.

Dr Schnoll, who is also coleader of the Tobacco and Environmental Carcinogenesis Program at Abramson Cancer Center and is a senior fellow at the Center for Public Health Initiatives, said he found the rationale for the controversy surrounding e-cigarettes "kind of offensive."

"As someone who works with adults trying to quit smoking and as a scientist studying new methods of smoking cessation, rigorous evaluation of new ways to help current combustible smokers quit is needed. I'm not a victim of the [tobacco industry's] divide-and-conquer strategy," he said.

Randomized controlled trials are needed to better understand the potential role of e-cigarettes, said Dr Schnoll. Results based on the current study's analytic approach may not be accurate, he said, pointing to a recent UK survey study of adolescents. It showed that 34.4% of teenagers who had tried e-cigarettes said that a year later, they had tried cigarettes. By comparison, only 9% of teenagers who had not tried e-cigarettes when the survey began said they had tried cigarettes at 1-year follow-up.

To complicate matters, new e-cigarettes are being introduced all the time. "What we study today may not be relevant to what's being smoked tomorrow," Dr Schnoll explained. "It's an unregulated marketplace with up to 300 products made up of different constituents. You can't roll them into one numeric value that represents risk."

Also approached for comment, Joaquin Barnoya, MD, MPH, associate professor of surgery at Washington University School of Medicine, in St. Louis, Missouri, said he found the article interesting but emphasized that clinicians should first support evidence-based cessation strategies when talking to patients who want to quit smoking. Physicians should also make sure that other strategies proven to increase the odds of quitting with or without smoking cessation aids are implemented. These include living in a smoke-free home.

Given these caveats, Dr Barnoya is not dead set against recommending a switch to e-cigarettes, provided vaping does not become a crutch that evolves into a dual smoking habit. "If a smoker wants to try e-cigarettes, I would not discourage them, but make sure they keep focused on completely quitting smoking and ultimately become smoke free," he told Medscape Medical News.

"e-Cigarettes are not a single product but three generations of products with different characteristics," he pointed out, adding that smokers need to be made aware that the health consequences of smoking e-cigarettes are "not yet fully defined." Clinicians must also "reinforce that e-cigarettes should not be used in an attempt to circumvent smoke-free laws," Dr Barnoya said.

Margie Clapper, PhD, deputy scientific director and coleader of the Cancer Prevention and Control Program at Fox Chase Cancer Center in Philadelphia, Pennsylvania, said that studies of e-cigarettes have suffered from the fact that the products are unregulated and of unknown composition. "The conclusions made in this article are unsubstantiated by concrete data," she told Medscape Medical News. "We do not know what the health risks of e-cigarette use are and may not know for decades."

One small study has suggested that smoking just one e-cigarette could expose users to enough nicotine to contribute to high blood pressure and other health problems. In addition, a recent pilot study on the potential impact of e-cigarettes on bladder cancer reported the presence of two known carcinogens, otoluidine and 2-naphthylamine, in the urine of e-cigarette users but not in nonusers.

Dr Clapper emphasized that the "ability of e-cigarettes to facilitate smoking cessation remains controversial," and cautioned that there is no standard message that clinicians can convey to patients who want to quit smoking about switching to e-cigarettes. "Never before have humans intentionally inhaled either heated liquid nicotine [the stabilizers in e-cigarettes] or any type of flavor," she said. "Smokers should be well informed about the potential risks vs benefits of e-cigarette use by their clinician before making a decision to use them."

A recent laboratory study of more than 140 commonly used flavors of e-cigarettes found that regular use, particularly of cherry-flavored e-cigarettes, often results in exposure to benzaldehyde, an aromatic aldehyde used in food and cosmetics. Benzaldehyde has been shown in previous animal and occupational exposure studies to cause respiratory airway irritation.

Although carcinogenic compounds and heavy metals have been identified in e-cigarette vapor, Dr Clapper confirmed that the impact of vaping on overall health, particularly in teens, remains unknown. However, evidence of adverse health effects associated with inhaling a sweet flavor has been reported in popcorn factory workers, she pointed out. Similarly, the negative impact on health of inhaling artificial fog ― an ingredient used as an e-cigarette stabilizer ― has been documented in stage actors. "This raises significant concern regarding the detrimental effect of intentional exposure on the respiratory system, especially in developing adolescents," Dr Clapper said.

The good news is that there is light on the research horizon in the form of a standardized research e-cigarette (SREC), say Dr Scholl and Dr Clapper. Requests for proposals were recently announced to investigate the use of a SREC developed for clinical and research testing by the National Institutes of Health. This research will focus on smoking cessation, associated addiction, the effect of the e-cigarette on cardiac and pulmonary health and cancer progression.

SREC could be a safer way to help smokers quit, said Dr Schnoll, adding that the harm of e-cigarettes needs to be systematically assessed. He predicts that in the next 5 years, a series of randomized controlled studies will be conducted to determine whether SREC helps people quit smoking and whether it can reduce the harms of combustible smoking.

"The resulting data are anticipated to provide insight into the issues raised by this article," said Dr Clapper. Until then, she emphasized, "existing data are insufficient to support any conclusive statements."

Funding for the study was provided by the National Institute on Drug Abuse and the National Cancer Institute. Dr Levy has disclosed no relevant financial relationships. Coauthor Maciej L. Goniewicz, PhD, PharmD, reports relationships with Pfizer and Johnson & Johnson. Other study authors, Dr Hefler, Dr Clapper and Dr Bornoya have disclosed no relevant financial relationships. Dr Schnoll reports a relationship with Pfizer.

Tob Control. Published online October 2, 2017. Full text, Editorial

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