Is vaping safer than smoking? Depends who you ask, and what scientific study they point to

In the past few months, vaping has turned into something critics say is little – or even no better – than smoking.

The claim is central to the future of electronic cigarettes. Within weeks, the Food and Drug Administration is likely to finalize its ban on flavored e-cigarettes.  About a month after that, vaping companies will have to remove flavored e-cigarettes from stores until they receive FDA approval to reenter the market. 

By May 2020, companies have to submit costly applications to the FDA with proof that their products are safe and help enough adults quit smoking to offset the harm in creating millions of vapers who may start smoking.  Products sold by the big tobacco companies that aren't popular with teens, such as Vuse, may be the only ones to pass muster, says American Vaping Association founder Gregory Conley. 

The relative safety of vaping compared with smoking is an important part of the consideration, and people on both sides of the debate use scientific studies as weapons in an intensifying public health battle.

Smoking tobacco kills about 480,000 people a year in the USA, and the World Health Organization says up to half the people who smoke will die because of it. Nationwide, vaping is linked to at least 18 deaths and nearly 1,100 cases of lung injury reported by federal health officials. Four out of five of the cases involve the vaping of products with THC, the principal psychoactive compound in marijuana, alone or with nicotine. 

The Centers for Disease Control and Prevention published research showing 27% of high school students used tobacco products last year and the percentage of those who used flavored e-cigarettes was up from 65% in 2014 to almost 68% in 2018.  

Advocates on both sides say it's impossible to make conclusive determinations because vaping has been around only a decade. Still, they cite various studies to support their respective points:

Vaping is safer? 

Vaping is 95% safer than smoking 

Point: Public Health England, a federal agency in the United Kingdom, last December reiterated its 2015 conclusion that vaping is 95% safer than smoking cigarettes. Britain's Public Health Service recommends vaping to smokers; vape shops often operate in hospitals. Clive Bates, a former director of the U.K. anti-tobacco group Action on Smoking and Health, calls efforts to discredit this research part of a "consistent effort to create moral panic around vaping." 

        Counterpoint: Albert Rizzo, chief medical officer of the American Lung Association, scoffed at the U.K.’s conclusion during a House oversight committee hearing last month, calling smoking a “low bar to beat.” He cited an editorial in The Lancet medical journal in August 2015 that highlighted the industry funding of much of the research and many unmentioned caveats about weak evidence cited by the British authors. The editorial concluded the statistic was based on an "extraordinarily flimsy foundation.”   

Vaping has fewer chemicals and at a lower level than smoking 

There's "conclusive evidence" that completely switching from smoking to e-cigarettes "reduces users' exposure to numerous toxicants and carcinogens present in combustible tobacco cigarettes," the National Academies of Science, Engineering and Medicine reported in January 2018. This finding was backed up last December in an investigation by Maciej Goniewicz of the Roswell Park Comprehensive Cancer Center, writing in the Annals of Internal Medicine. 

        Vince Willmore, spokesman for the Campaign for Tobacco-free Kids, points to the academies' conclusion that “the absolute risks of the products [e-cigarettes] cannot be unambiguously determined at this time.”

Vaping shows less evidence of disease

Of 45 biomarkers – indicators of toxic chemical exposure that cause disease – the authors of a December 2018 study in the Journal of the American Medical Association found 12 were detectable among those who vaped compared to none in nonsmokers. People who only vaped showed up to 98% lower concentrations of exposure biomarkers than people who only smoked. The main biomarkers of chemical exposure that cause cancer - which are monitored because it's too early to tell if vaping causes cancer - were much lower than smoked tobacco. New York University public health professor and clinical psychologist David Abrams says this study is largely consistent with Public Health England's findings. 

    The study doesn't examine whether e-cigarettes effectively help smokers quit smoking completely, "which is the only way for smokers to truly protect their health and reduce their exposure to these toxicants," said Willmore of the Campaign for Tobacco-free Kids. As the National Academies report found in 2018, the overall evidence that e-cigarettes are effective for smoking cessation is “limited," he said. 

Vaping is twice as effective at getting people to quit smoking than other nicotine replacement therapies 

In a randomized trial of 900 smokers, 18% of those using e-cigarettes were not smoking after one year, and 9.9% of those using other forms of nicotine-replacement therapies, such as gum and patches, were smoke-free. The findings were reported in the New England Journal of Medicine. 

    Pulmonologist and University of Minnesota medical professor Anne Melzer cites an analysis out this year in the journal Tobacco Control that used federal data from 2013 to 2015. It found that a year after starting e-cigarettes, nearly half of participants were still smoking and vaping, 5% were only vaping and 7% had quit both products.  "Not an extremely high rate of cessation compared with usual evidence-based treatments for cessation," Melzer said.   

Vaping may not be safer 

70% of people who tried to quit smoking using vaping continue to do both 

The finding is from the report in the journal Tobacco Control in 2015. Melzer, who is a member of the Tobacco Action Committee of the American Thoracic Society, noted "dual users" have a much higher level of carcinogenic chemicals in their blood than people who only smoke or vape, 

    "There's an error of omission," says Abrams, citing a study in Harm Reduction Journal in 2018. "Dual users may be in transition before they switch completely, and a study suggests they take from a few days to several years and also switch during that time to flavors other than tobacco."     

E-cigarettes are associated with a lower likelihood of quitting

E-cigarettes "as currently being used" are associated with significantly less quitting among smokers, according to a meta-analysis – an analysis of many studies – co-written by University of California-San Francisco professor Stanton Glantz in 2016. "Although quitting smoking is a common marketing claim and is often cited as a reason for use among cigarette smokers, the overall conclusion from the available studies is that e-cigarette use is not associated with reduced smoking cessation in the real world."

        “Dr. Glantz’s meta-analysis included studies that were not designed to determine the efficacy of e-cigarettes for quitting smoking, including a study that I authored," says clinical psychologist Judith Prochaska, an associate professor in the Department of Medicine at Stanford University.

A study in 2017 in the journal Addiction refuted Glantz's findings as well, noting "only a small proportion of studies" published could even address the issue. 

Vaping causes heart attacks 

study in June co-written by Glantz says vaping doubled the risk of heart attacks. Glantz went further in a blog post calling the findings "more evidence" of the heart attack link. The study was published in the Journal of the American Heart Association,  

        Two studies out this month by academic researchers who replicated Glantz’s study found there was no connection between heart attacks and vaping. One report was published in the American Journal of Preventive Medicine, and the other, co-written by psychologist and New York University public health professor Ray Niaura, was published in Therapeutic Advances in Chronic Disease. In July, University of Louisville professor Brad Rodu came to the same conclusion, noting Glantz failed to mention most of the people in the study had their heart attacks before they started vaping. 

Teens who vape are far more likely to smoke

High school seniors who vaped were four times more likely to smoke cigarettes — even if they started out with the highest perception of smoking's risk, according to researchers at the University of Michigan writing in the journal Tobacco Control in 2016. "Vaping as a risk factor for future smoking is a strong, scientifically-based rationale for restricting youth access to e-cigarettes," said the report, co-written by University of Michigan's Richard Miech, who is co-investigator of the National Institute of Drug Abuse's Monitoring the Future report. Their work showed vaping could reverse or at least erase the public health progress in reducing the rate of smoking in the USA. 

    "In the mid-late 2000s, the decline in smoking among youth slowed considerably and then stagnated. Anyone who claims that smoking rates among youth and young adults would be as low as they are today without vaping products around to further denormalize smoking is either disingenuous or smoking something more potent than cigarettes," said Conley of the American Vaping Association. 

Photos by American Lung Association; Roswell Park Comprehensive Cancer Center; New York University; Noah Berger; Stanford University; Hannah, Gaber, USA TODAY and Michael McIntyre

This article originally appeared on USA TODAY: Is vaping safer than smoking? Studies differ as lung injury cases rise