Double Check: Is Vaping Safer Than Smoking?

Government health body Public Health England (PHE) endorsed an estimate that vaping is "95 percent safer than smoking" in 2015. The U.K.'s National Health Service continues to advise that "vaping poses a small fraction of the risk of smoking cigarettes" while suggesting that it can help people quit smoking. 

But 32 countries, including India, Brazil, Qatar, Singapore and Mexico, have banned the sale of e-cigarettes entirely, according to the World Health Organization (WHO), which says that they are addictive and "not without harm". Another 79 countries have imposed regulations and restrictions on their use. 

So what does this mean for someone trying to decide whether to vape? Does evidence back the ‘95 percent safer’ claim? Even if the specific claim is not true, is it accurate to say that the harms or risks of vaping are a 'small fraction' of those from regular cigarettes? And is vaping a viable plan to quit smoking?

Where Did the '95 Percent Safer' Claim Come From?

In 2014, PHE found that the danger from e-cigarette products on the market at the time "is likely to be extremely low, and certainly much lower than smoking" and that "the health risks of passive exposure to electronic cigarette vapour are likely to be extremely low." They cited two expert studies as the basis for their conclusions, one of which, published in the European Addiction Research journal, said e-cigarettes had only about four percent of the maximum relative harm of other tobacco products. 

PHE has reviewed and updated its findings every year since, in light of any new studies about safety that may have been done. The 2015 report reiterated the findings of the 2014 review and, crucially, concluded that there was "a need to publicize the current best estimate that using [e-cigarettes] is around 95 percent safer than smoking." This report was widely covered in the press, leading to the spread of this claim about the relative safety of e-cigarettes. 

The latest report, published under the aegis of the new Office for Health Improvement and Disparities, asserts that "vaping poses a small fraction of the risks of smoking" in the short and medium term. The study notes that vaping isn't risk-free, particularly for non-smokers, but there has been no change from the PHE's previously expressed stance that vaping is an effective way to quit smoking. The National Health Service (NHS) in England also says that there is evidence that e-cigarettes can help a person to quit smoking. 

Does This Claim About Safety of E-Cigarettes Still Hold Up?

In 2020, several researchers, including experts asked to testify in litigation against tobacco and e-cigarette companies, challenged the "95 percent safer" estimate. At the outset, they pointed out that the paper in European Addiction Research that pioneered this estimate had noted that "a limitation of this study is the lack of hard evidence for the harms of most products on most of the criteria."

They referred to numerous subsequent studies which detailed several harms from e-cigarettes, including toxic effects of certain chemicals, cardiovascular risk, and lung damage. Since 2013, when research for the study had been conducted, there were entirely new kinds of e-cigarette devices on the market, as well as new liquids for the devices – even where the latter were safe to eat, their pulmonary toxicity (effect on a person’s lungs) was unknown. As a result, it was argued that the '95 percent safer' claim was a "factoid," i.e. "unreliable information repeated so often that it becomes accepted as fact."

This article was not the first to challenge the '95 percent safer' claim, with some challenges raised to it in 2015, including in the British Medical Journal. However, it offered one of the more comprehensive rebuttals of the claim. While the PHE did not change their view based on new research over the years, other countries and health bodies had begun to take notice. 

In September 2019, the Indian government imposed a complete ban on e-cigarettes. Both the Indian Council for Medical Research (ICMR) and the Indian Medical Association (IMA) had previously published white papers on the harmful effects of vaping, advocating for prohibition. 

The ICMR pointed out that research had shown e-cigarette use "adversely affects the cardiovascular system, impairs respiratory, immune cell function and airways in a way similar to cigarette smoking and is responsible for severe respiratory disease." It noted that there had been studies which showed that pregnant women who were users or even exposed passively to aerosols from e-cigarettes were adversely affected and that it could have severe consequences for children in the womb.

According to the IMA, two substances found in e-cigarette liquids, "propylene glycol and glycerol, decompose to form the carcinogens formaldehyde and acetaldehyde, with levels depending on the voltage of the battery used in the e-cigarette." The white paper added, "Most believe that inhaling e-cigarette vapour is likely to be less harmful than inhaling cigarette smoke, but the consequences of chronic inhalation of e-cigarette vapour are unknown, and levels of toxic and carcinogenic compounds may vary by e-cigarette liquid components and device used." 

Logically spoke to Dr. DR Rai, former Secretary General of the IMA, who expressed his concern about the PHE's seeming advocacy of e-cigarette usage. In his opinion, "E-cigarettes are as harmful as normal cigarettes. They affect the cardiovascular system and damage the nervous and immune systems". He explained that vapes use "vaporized nicotine, propylene, and glycol, which have carcinogenic properties." 

In comments to Logically, Dr. Arvind Kumar, Chairman of the Institute of Chest Surgery and Lung Transplantation at Medanta Hospital Gurugram, did not go so far as to say the effects were the same, but cautioned that while the cigarette industry, to some extent, is regulated, and a lot of research is available on the effects of smoking cigarettes, there was little to no conclusive evidence on how harmful e-cigarette usage could end up being. "They can majorly impact the lungs, causing breathlessness, and in the long run, cause fibrosis and inflammation," he added, referring to case studies he had observed.

Even If Not '95 Percent Safer', Aren't E-Cigarettes Still Less Dangerous?

Professor Ann McNeill, one of the authors of the PHE's review into the relative harms of e-cigarettes, told Logically that she doesn't believe that e-cigarettes are harmless; however, they can help people to stop smoking. 

"We are not telling people to vape," she said. "Instead, we are telling them methods to try to quit smoking." Speaking about the restrictions by other countries, she argued that "if a country bans e-cigarettes, tobacco cigarettes are easily accessible." 

Explaining why she believes e-cigarettes are less harmful than cigarettes, she said, "Vapes are made of propylene glycol, flavoring, and typically nicotine. They don't contain tobacco like cigarettes. When you light tobacco, it causes cancer. You don't get that in an aerosol, making emissions from vapes different from that of a cigarette." In her view, the "biomarkers of carcinogens in vapes are much lower than cigarettes." 

Accepting that the PHE research had several limitations, she suggested that "a lot of research in this area isn't of high quality," and "we need to have bigger and longer studies."

In a Johns Hopkins Medicine explainer on how vaping affects a person's lungs, one of the hospital's lung cancer surgeons, Dr. Stephen Broderick, took a view similar to that of Kumar. "With tobacco, we have six decades of rigorous studies to show which of the 7,000 chemicals inhaled during smoking impact the lungs," he said. "But with vaping, we simply don't know the short- or long-term effects yet and which e-cigarette components are to blame."

Vaping can cause severe lung diseases, the Johns Hopkins surgeon cautioned. These include ‘popcorn lung’ (bronchiolitis obliterans, i.e. damage to small airways of the lungs), lipoid pneumonia (where the oils lead to inflammation of the lungs), and ‘collapsed lung’ (primary spontaneous pneumothorax, i.e. when oxygen escapes from a hole in the lung).

But this is where things get tricky. Dr. Broderick identified several concerning substances that are either present in the liquid used for e-cigarettes or produced when heated: diacetyl (which causes popcorn lung), formaldehyde, and acrolein. However, he noted that the substance at the center of investigations into the harms caused by e-cigarettes is the vitamin E used as a thickening and delivery agent in certain e-liquids.

In late 2019, there was an outbreak of cases across the U.S. of what the CDC termed E-cigarette or Vaping Use-Associated Lung Injury (EVALI). From August 2019 to February 2020, federal data showed 2,807 cases of hospitalization or death because of EVALI. In its analysis of the outbreak, the CDC stated that lab data showed that the vitamin E acetate used in vaping liquids was strongly linked to the EVALI outbreak." They cited a study which found vitamin E acetate in the lung samples of 48 out of 51 EVALI patients across multiple states as an example.

According to the CDC, however, vitamin E acetate is an additive in some e-cigarette products containing THC – tetrahydrocannabinol, i.e., the key psychoactive component of cannabis. An editorial in November 2022 in the journal Addiction by a group of experts subsequently pointed out that vitamin E acetate is not soluble in nicotine e-liquids, citing research published in 2021. Arguably meaning that only vaping THC-containing e-liquids is risky and that nicotine-only e-cigarettes are relatively safe.

Of course, it is not that simple. The CDC's research indicated that in 14 percent of the EVALI cases it reviewed, the patients said they vaped only nicotine products. Some researchers have contested this figure, noting that people may try to hide their consumption of THC-containing products for various reasons. However, there has been independent research into some other substances found in e-liquids, like propylene glycol, which are dangerous when vaporized.

Interestingly, while the U.S. Food and Drug Administration (FDA) has expressed concern over the levels of e-cigarette consumption among American youth, there are no federal restrictions in the country on e-cigarette sales in general. However, some states have imposed bans on online sales, and the FDA has sought to ban sales of certain products. 

The concern over youth usage of e-cigarettes is fairly universal at this point, and regardless of any confusion over the difference in harm between e-cigarettes and regular cigarettes, the prevailing guidance by all health bodies is that youths or young adults should not use them.

While e-cigarettes do not cause some of the serious recognized harms from tobacco, there does not appear to be enough evidence to conclusively say that the substances used in e-cigarettes (or created upon vaporization) are genuinely safe. Further research is needed to confirm exactly how the harms caused by these substances compare to smoking regular cigarettes, especially in the long-term.

Can Vaping be Used to Quit Smoking? 

The health services in England and New Zealand continue to recommend vaping as a means to quit smoking while acknowledging that it is not entirely safe.

Despite its concerns over the possible harms of e-cigarettes, the CDC acknowledges that they can benefit adult smokers who are not pregnant if they can completely substitute regular cigarettes with them. At the same time, it also notes that further research is needed to assess how effective they are at helping people quit smoking.

The lack of conclusive research on this issue means that Kumar does not recommend vaping even for this limited purpose. "We have proven and tested methods of quitting smoking, and someone wanting to leave should only resort to practices backed by scientific research," he told Logically. 

A similar stance has also been taken by the Australian health authorities. In guidance issued in November 2022, the Australian government notes that nicotine vaping products are not a "first-line treatment for smoking cessation." While smaller studies have indicated they might be more effective than existing options, these are not backed up by reliable, large-scale studies. "The strongest evidence base for efficacy and safety is for currently approved pharmacological therapies combined with behavioural support", they contend.

If you are looking to quit smoking, please consult your country’s health services and guidelines to identify a safe and effective approach for you.  

With inputs from Vakasha Sachdev and Ernie Piper.