American Heart Association Claims that Vaping Causes Severe Strokes and is More Risky than Smoking

In a press release issued last Thursday, the American Heart Association claimed that vaping causes severe strokes and poses a higher risk of severe strokes than smoking.

According to the press release: "E-cigarettes may pose the same or higher risk of stroke severity as tobacco smoke. ... Electronic cigarette (e-cigarettes) vaping may pose just as much or even higher risk as smoking tobacco for worsening a stroke, according to a preliminary study in mice presented at the American Heart Association's International Stroke Conference 2017. ... From a brain health perspective, researchers said, electronic-cigarette vaping is not safer than tobacco smoking, and may pose a similar, if not higher risk for stroke severity."

The American Heart Association's statement was spread widely through the media. For example, here's just one headline that appeared: "E-cigs could raise the risk of suffering a stroke more than smoking."

The Rest of the Story

The American Heart Association's conclusion that vaping poses an equal or higher risk of suffering a severe stroke is based on a single mouse study. In this study, which has not been published or peer reviewed, but was presented last week at the American Stroke Association’s International Stroke Conference, the investigators found that mice exposed to e-cigarette aerosol for 10 days or 30 days had more severe strokes than those exposed to tobacco smoke.

To extrapolate from this single pre-clinical, animal study to population-based human health effects is ludicrous. There are many reasons why stroke-related findings from rodent studies do not translate well to humans. For example, as Braeuninger and Kleinschnitz point out:

"There are, of course, significant physiological, neuroanatomical and metabolic differences between humans and small rodents, which are the most widely used experimental animals in preclinical stroke research. For example, small rodents usually require higher drug doses on a mg/kg body weight basis for a similar effect than larger mammals. Thus, effective doses derived from preclinical stroke studies in small rodents cannot simply be transferred to the situation in humans, even if adjusted for body weight."

There is no scientific justification for the American Heart Association spreading the conclusion that vaping causes strokes. Nor is there any scientific justification for spreading the message that vaping poses a higher risk of suffering a stroke than smoking.

This blatant disregard for the truth, which I would term "public health malpractice," is not only unscientific but it is also damaging to public health. There are literally millions of smokers who have considered, or are currently considering, the question of whether or not to switch from smoking to vaping. Thanks to the American Heart Association, we can expect that huge numbers of smokers will choose to stick with smoking and that many ex-smokers - who quit via e-cigarettes - will decide to return to smoking.

After all, if vaping poses a greater risk of stroke than smoking, then there is absolutely no reason to quit smoking using e-cigarettes. You'd be better off smoking. And if you already quit smoking by switching to e-cigarettes, then you'd be better off returning to smoking than continuing to vape. Why take a chance of increasing your risk of suffering a stroke?

You can see why I call this an example of public health malpractice. The American Heart Association is essentially advising smokers that they are better off continuing to smoke than quitting smoking and switching completely to vaping. This is perhaps the most absurd medical advice I have ever heard in my entire career in medicine and public health. Even the tobacco companies - in the worst of their behavior - never told smokers that they would be at greater risk of disease if they quit smoking. But that is precisely what the American Heart Association is essentially telling smokers.

If the American Heart Association has any regard for scientific accuracy and professional responsibility in communication, it will offer an immediate retraction, correction, and apology for this action.

If that happens, I will report it here as soon as I become aware of it.

Tobacco Control Journal: There Can Be No Legitimate Discussion of Our Articles Without Our Permission

In a revelation of the religious-like character of the modern-day tobacco control movement, the journal Tobacco Control has suggested that there can be no legitimate discussion about articles it publishes without its permission; that is, on the Rapid Response forum at the journal's own web site. All other discussion of the scientific validity of journal articles is apparently illegitimate and inappropriate.

In an unprecedented editorial (I've never before seen a journal argue that the only legitimate forum for discussion of its articles is in the journal itself), the journal writes:

"the growing use of personal blogs to criticise published articles has led us to reflect on appropriate ways of engaging in such debate ... the proper place to pose questions and debate conclusions from research published in Tobacco Control is directly to the authors, in the form of a Rapid Response. ... placing personal blog posts or social media messages complaining about a study ... do not advance the field or allow an appropriate scientific dialogue and debate. ... As a result of discussion about these issues, the Tobacco Control editorial team has now established a policy that editors will not respond to external blog posts or social media messages about specific studies. ... We will always welcome legitimate criticism of methods, results and interpretation of published research. But we will discourage engagement with and dissemination of polemics that contribute to public misunderstandings and create conflict. As journal editors, we encourage constructive criticism and debate in ways that strengthen the evidence base for effective tobacco control policy rather than amplifying individual voices."

The Rest of the Story

I have never seen a scientific journal make such a bold statement. Do you mean to tell me that the only legitimate scientific discussion of an article published in a journal is that which takes place in the journal itself, in a forum that is managed and controlled by the journal? Do you mean to tell me that any other discussion or criticism of research articles is not constructive and serves only to "amplify individual voices?"

Moreover, what is wrong with creating "conflict" if it is warranted because the conclusions of an article are not supported by its findings? In fact, a blogger who is criticizing the conclusions of a study because they are warranted is not "creating" conflict. What is creating conflict is the fact that the paper disseminated those unwarranted conclusions and that the journal chose to publish this shoddy science in the first place.

The editorial does not specify exactly what irked the journal so much that it boldly went where no journal has gone before and declared that any discussion of its articles outside of its own purview is illegitimate. However, I think it's quite clear that what irked the journal was criticism on several blogs - including my own - of an article that concluded vaping is a gateway to youth smoking based on a sample of 4 nonsmoking youth who experimented with e-cigarettes and then went on to try one or two cigarettes.

In this study, the sample size of youth who were nonsmoking, recent vapers at baseline was only 13 and the number of youth in this category who "initiated" smoking was only 4. Thus, the sweeping conclusion of the paper, which has been publicized internationally, was based on only 4 kids! Moreover, despite having a sample size of 347 high school seniors, the study could not find a single student who became an actual new smoker after having experimented with e-cigarettes. The few students (a grand total of 4) who did try a cigarette or two did not progress beyond having one or two cigarettes.

Rather than simply admit that it made a mistake and this unwarranted conclusion slipped through the cracks, the journal instead tried to divert attention from its mistake by attacking the messengers: those like myself who pointed out the error.

It's unfortunate that the journal chose to respond in an ad hominem manner rather than to actually address the substantive scientific question, which is whether or not the conclusion that vaping is a "one-way bridge" to smoking among youth can be justified based on the finding that 4 youth who were nonsmokers at baseline and who had experimented with e-cigarettes went on to smoke one or two cigarettes in the next year (and did not become smokers).

The issue is whether that is the kind of scientific evidence that legitimately supports the paper's conclusion that vaping is a gateway to smoking, rather than the method by which a blogger who notes this study weakness should attempt to correct the public health damage done by the publication of the article.

I don't know whether the editorial was directed at me or at other bloggers, or both, but I can assure my readers that I will not stop providing discussion of the scientific research regarding electronic cigarettes just because one journal wants to control the entire discourse on the subject.

Kentucky Health Group is Deceiving Public About Risks of Smoking ... and It's Working

A Kentucky health group has orchestrated a campaign to deceive the public about the terrible health hazards associated with smoking by downplaying those risks. Sadly, a recent public opinion poll commissioned by the group demonstrated that its campaign of deceit is working. Adults in Kentucky have been completely fooled about the serious health risks of smoking.

According to the Foundation for a Healthy Kentucky: "Research suggests that e-cigs may be a gateway to using other forms of tobacco, and they can be just as harmful."

The Rest of the Story

There is abundant evidence that vaping is much safer than smoking. In stating that vaping is just as harmful as smoking, the Foundation for a Healthy Kentucky is lying to the public. Moreover, this campaign of deceit is undermining the public's appreciation of the severe health hazards associated with smoking. If smoking is no more hazardous than vaping - which doesn't involve the burning of tobacco - then it must not be as harmful as previously thought.

I can assure you that if the tobacco industry were making the same claims, we would be attacking them and taking them to court for public fraud. But the Foundation for a Healthy Kentucky is making precisely that claim which would have us dragging Big Tobacco into the courtroom. Why is it OK for us to lie, but not the tobacco companies?

A recent public opinion poll commissioned by the Foundation for a Healthy Kentucky showed how successful its campaign of deceit has been. According to this poll, 64% of Kentucky adults believe that smoking is no more hazardous than vaping. And nearly one in five (19%) actually believe that vaping is more hazardous than smoking!

Interestingly, nowhere in its report or press release does the Foundation point out that these 64% of Kentuckians are wrong in thinking that smoking is no more hazardous than vaping. If anything, the report appears to lament the fact that 29% of adults in Kentucky think that vaping is safer than smoking.

What a tremendous disservice the Foundation for a Health Kentucky is doing by misleading the people of Kentucky into thinking that smoking is no worse for your health than using a product which doesn't even contain any tobacco and doesn't involve any combustion.

It is also contrary to public health to bemoan the fact that a segment of the public has a correct understanding of relative health risks. Our goal should be to aim for 100% of the public to have a correct understanding of relative health risks, not to try to deceive the public so that they don't have correct information.

I'll be watching to see if the Foundation for a Healthy Kentucky corrects this misinformation. Until that happens, they are harming the public's health by decreasing the likelihood that smokers will quit and increasing the likelihood that vapers will return to smoking.

Tobacco Control Study Provides Strong Evidence that Vaping is Not a One-Way Bridge to Smoking

I have already shown (post 1; post 2) why the recently published study in Tobacco Control which purported to demonstrate that vaping is a "one-way bridge to cigarette smoking among youth" actually provides no evidence that e-cigarette experimentation is a gateway to smoking.

First, the exposed group consisted of any youth who had even puffed once on an e-cigarette in the past 30 days. Second, the outcome variable was having puffed even once on a cigarette in the past year. Thus, the study cannot document either that the "recent vapers" were actually regular vapers or that the youth who "initiated" smoking were actually smokers. A more likely explanation of the study findings is that youth who engage in e-cigarette experimentation are also more likely to try cigarettes.

Second, I revealed that the sample size of youth who were nonsmoking, recent vapers at baseline was only 13 and that the number of youth in this category who "initiated" smoking was only 4. Thus, the sweeping conclusion of the paper, which has been publicized internationally, was based on only 4 kids.

Today, I reveal that not only does the study fail to provide any evidence that vaping is a gateway to smoking, but it actually provides strong evidence that vaping is not a gateway to smoking.

The Rest of the Story

If you read the fine print in the paper, there is a key finding which is not mentioned anywhere in the abstract, the discussion, or in any of the newspaper articles written about this study. The fine print is this:

"Among the group of new smokers at follow-up who had recently vaped at baseline, all reported that they had smoked cigarettes at the level of ‘once or twice’ in the past 12 months at follow-up."

Another way of stating this is that:

"Among the group of new smokers at follow-up who had recently vaped at baseline, not a single one had smoked more than two cigarettes in the entire past year."

In other words, this study actually confirms that none of the nonsmoking, recent vapers became actual smokers. Apparently, they tried a cigarette or two, but not a single one of them continued to smoke beyond that!

What this means is that despite having a sample size of 347 high school seniors, this study could not find a single student who became an actual new smoker after having experimented with e-cigarettes. The few students (a grand total of 4) who did try a cigarette or two did not progress beyond having one or two cigarettes.

It is striking to me that this study, which provides strong evidence that vaping is not a gateway to smoking, could conclude quite definitively that vaping is a "one-way bridge" to smoking. It creates the appearance that the study reached a pre-determined conclusion and was going to twist the findings any way it could to come up with this conclusion.

It is puzzling that not a single reviewer nor editor at Tobacco Control was able to detect this sleight-of-hand.

How do you get from a finding that not a single nonsmoking youth who experimented with vaping at baseline progressed to become an actual smoker at follow-up (and that only 4 kids in that category even tried a cigarette in the first place) to a sweeping conclusion that vaping is a one-way bridge to cigarette smoking among youth?

The answer, and the rest of the story, is that this is essentially hocus pocus. And while it may have gotten by the peer reviewers and editors, it doesn't get by me or any of the many colleagues with whom I have discussed this study. Even my students with whom I have discussed this easily see what is going on here.

Failure to Disclose Sample Size: A Flaw at Multiple Levels

Yesterday, I revealed that a new study published in the journal Tobacco Control which concluded that e-cigarettes are a "one-way bridge" to youth smoking failed to disclose the sample size upon which its major conclusion was based. It turns out that the paper's sweeping conclusion was based on only 4 kids who had tried an e-cigarette at baseline and went on to try a cigarette in the next year. That sample size was not even revealed in the online supplement to the article. I had to calculate it from the raw data. The supplement did reveal that there were only 13 nonsmokers in the study who had vaped in the past month. Thus, I argued that the paper really should have concluded not that vaping is a gateway to smoking but that e-cigarette experimentation among nonsmokers doesn't appear to even be a gateway to regular vaping.

A further analysis of the paper reveals that among the 4 youth who had supposedly progressed to smoking, none of them had smoked more than two cigarettes in the past year. According to the paper: "Among the group of new smokers at follow-up who had recently vaped at baseline, all reported that they had smoked cigarettes at the level of ‘once or twice’ in the past 12 months at follow-up."

What the paper doesn't reveal is that this "group" of new smokers consists of only about 4 kids.

This raises the question of why the paper doesn't share this information with the reader. To talk about a "group" of new smokers who had vaped at baseline, but without informing the reader that there are only 4 kids in this "group" seems misleading.

The Rest of the Story

It appears to me that there were three levels of failure which explain why this paper violated what is perhaps the most important aspect of scientific reporting: revealing the sample size upon which your major conclusion is based.

First, the paper itself should have disclosed this sample size. It seems critical for readers to understand that the paper's major conclusion - that there was a 4.8 times higher rate of "smoking initiation" among nonsmokers who had vaped in the past month - was based on 4 kids having tried a cigarette or two in the past year.

This failure has already led to deceptive headlines, such as this one in the Daily Mail: "E-cigarettes are a One-Way Bridge to Tobacco." A more accurate headline would have said something like: "Researchers Can't Find More than 4 Kids Who Progressed from Vaping to Smoking, and Even Those Four Had Only Smoked Once or Twice in their Lifetimes." Or: "E-cigarette Experimentation among Nonsmokers Found Not to Be a One-Way Bridge to Vaping, Much Less Smoking."

The second failure is upon the peer reviewers of the manuscript. How could the reviewers possibly have not caught the glaring omission from the paper of the sample size underlying its most important conclusion?

The third failure is that of the journal itself. It, too, should have caught the glaring omission from the paper of the sample size underlying its most important conclusion. I used to be a statistical/methodological editor for Tobacco Control and I can tell you that I never would have let a paper through that did not reveal the sample size upon which its major conclusion was drawn. It's difficult for me to understand how this occurred.

The rest of the story is that it is difficult not to agree with Professor Robert West's conclusion that e-cigarette researchers in the United States are "waging a ‘moral crusade’ against e-cigarettes" and that they are "exaggerating their findings." This may not be a conscious decision, but may reflect a deeper underlying bias against e-cigarettes.

New Study Concludes that Vaping is a One-Way Bridge to Cigarette Smoking among Youth

A new study published online ahead of print in the journal Tobacco Control concludes that vaping is “a one-way bridge to cigarette smoking among youth.”

(See: Miech R, Patrick ME, O’Malley PM, Johnston LD. E-cigarette use as a predictor of cigarette smoking: results from a 1-year follow-up of a national sample of 12th grade students. Tobacco Control. http://dx.doi.org/10.1136/tobaccocontrol-2016-0532910).

The study involved a one-year follow-up of 347 high school seniors who were surveyed at baseline in 2014 and at follow-up in 2015. At baseline, they were classified as recent vapers (used an e-cigarette in the past 30 days) or non-vapers. At follow-up, smoking initiation was defined as having smoked a cigarette in the past year.

In the key analysis, smoking initiation (smoking a cigarette in the past year) was compared between recent vapers (used an e-cigarette in the past 30 days) and non-vapers who had never smoked at the time of the baseline survey. The paper reports that the rate of smoking initiation was 31% among the recent vapers and 7% among non-vapers. In an adjusted analysis, recent vapers were 4.8 times more likely than non-vapers to initiate smoking during the follow-up period.

The paper concludes that “vaping is a one-way bridge to cigarette smoking among youth.”

The Rest of the Story

At first glance, this paper appears to demolish the claim that vaping is not a known gateway to youth smoking. The conclusion that is drawn is a sweeping one: e-cigarettes are a one-way bridge to cigarette smoking among youth. If this conclusion is true, then I believe e-cigarettes are not a tenable harm reduction strategy because the benefits of adults quitting using e-cigarettes would be offset by a substantial increase in youth becoming addicted to smoking and possibly suffering life-long health effects, disease, disability, and premature death.

So am I going to renounce my earlier conclusions (that there is no evidence vaping causes kids to start smoking)?

Perhaps, but not without a closer look at the study.

To be a valid conclusion, there must not be a plausible, alternative explanation for the study findings. The paper does not present any alternative explanations. But this doesn’t mean that there isn’t one.

In fact, there is a very plausible (and in fact, highly likely) alternative interpretation of these findings:

Experimenting with e-cigarettes is a sensitive marker of substance-related, risk-taking behavior in general, which strongly predisposes a youth to trying cigarettes.

What could easily explain the observed findings is that youth who experiment with e-cigarettes are also more likely to experiment with other substances, including cigarettes. Therefore, of course you are going to find a higher rate of cigarette experimentation among youth who have already experimented with electronic cigarettes. This should come as a surprise to no one.

The observed relationship between e-cigarette experimentation and cigarette experimentation could well be a spurious one, confounded by an underlying predisposition to substance-related, risk-taking behavior. Importantly, the study did not make any attempt to control for any measures of risk-taking behavior. Moreover, the study did not even control for underlying susceptibility to smoking.

There are two additional and related factors that cast serious doubt on the study’s conclusion.

First, the exposure variable – recent vaping – was defined as having tried even one e-cigarette in the past month. All we know about the baseline “vapers” is that they had taken a puff on an e-cigarette in the past month. We do not know that they were regular vapers. We do not know that they had become addicted to nicotine or to vaping. We don’t even know that they had tried vaping more than once in their entire life! So to conclude that this study demonstrates that vaping is a one-way bridge to smoking is not warranted.

Second, the outcome variable – smoking initiation – was defined as having tried even one cigarette in the past year. All we know about the smoking initiators is that they had taken a puff on a cigarette in the past year. We don’t even know that they had tried more than one cigarette in the past year. So to conclude that vaping is a bridge to smoking based on this definition is not warranted.

The question that arises is why the study did not examine whether frequent vapers were more likely to progress to regular smoking (or at very least, current or established smoking). According to the paper, the sample size was not large enough to allow such an analysis. But that raises the question: If the sample size was not large enough to allow an analysis of frequent vapers, was it large enough to allow an analysis of all vapers? And most critically, how many youths were there who were nonsmoking, recent vapers at baseline who tried a cigarette in the next year? After all, this is the sample upon which the entire conclusion of the study is based.

So I took a closer look at the study – well, not the actual study because the sample size of baseline nonsmokers who had recently vaped is not reported anywhere in the study. You have to go to a separate, online appendix to find this out.

So take a guess: How many youths is the sweeping conclusion of this paper based on? (i.e., how many nonsmoking, recent vapers at baseline progressed to having tried a cigarette at follow-up?)

a. 122
b. 84
c. 42
d. 21
e. 9

If you guessed E (9) ...

… then you are wrong.

The correct answer is none of the above. The total number of nonsmoking, recent vapers who tried a cigarette in this study appears to be just 4!

So you mean to tell me that the sweeping conclusion of this paper – that vaping is a one-way bridge to smoking – is based on 4 youth? Moreover, on 4 youth about whom all we know is that they tried an e-cigarette during the month prior to the baseline survey and then tried a cigarette in the following year. That hardly seems like a sufficient sample of youth upon which to rely to formulate national policy.

In fact, there were apparently only 13 nonsmokers who were recent vapers in the entire study of 347 youth. That itself should tell you something. Namely, that it is very difficult to find nonsmokers who vape with any significant frequency. In other words, e-cigarette experimentation is not any kind of significant bridge to youth smoking because it doesn’t even appear to be a bridge to regular or frequent vaping.

The rest of the story is that far from providing evidence that vaping is a one-way bridge to cigarette smoking among youth, this study provides further evidence that e-cigarette experimentation among nonsmoking youth doesn’t even appear to be a bridge to regular vaping. It is very difficult to find nonsmoking youth who experiment with e-cigarettes and then progress to become frequent vapers. In fact, it’s such a rare phenomenon that this study failed to achieve a high enough sample size to even analyze the rate at which these nonsmoking frequent vapers progressed to smoking. That itself is really the key finding of the paper.

This story illustrates why you have to be very careful in reading and interpreting the scientific literature. If you didn’t look at the supplemental material, which was not part of the article itself, you would never even be aware that the sweeping conclusions of this study were based on 4 kids.

All I can say is that when the FDA commissioner signs his first order putting a vape shop out of business, these 4 kids should be invited to the signing ceremony. Because it’s based on those 4 kids that vaping opponents apparently would like us to formulate national smoking policy.

Anti-Smoking Leader Demands Prosecution of Tobacco Company Executives for "Crimes Against Humanity"

An international anti-smoking leader has called for prosecution of the heads of the tobacco companies for "crimes against humanity."

According to an article in the Jerusalem Post:

"Prof. Judith Mackay, the British, Hong Kong-based physician who has been described by the tobacco industry as “one of the three most dangerous people in the world,” has called for heads of the industry to be prosecuted for their “crimes against humanity.” Mackay, an international anti-tobacco advocate who has led a campaign against tobacco in Asia since 1984, appeared by video conference at the annual meeting, held in a Caesarea on Friday, of the Medical Society for the Prevention and Cessation of Smoking of the Israel Medical Association."

The Rest of the Story

While the tobacco industry has done many despicable things and should be held civilly liable for damages caused by its products to users who became addicted prior to the time when the industry acknowledged that its products were deadly, prosecuting tobacco industry executives for "crimes against humanity" is going way too far.

Not only does this accusation go beyond reason, but it also undermines the significance of world leaders who have committed real crimes against humanity and is insensitive to the victims of these crimes. Moreover, it obscures the fact that the tobacco industry is not the only entity that was complicit in the tobacco epidemic.

Despite the condemnation-worthy actions of the tobacco companies, it must be remembered that it was the government that sanctioned the sale of tobacco products. At all times, the tobacco companies were acting in an environment in which the government made it legal to sell cigarettes. And although smokers did not necessarily make an informed decision to smoke, neither were they forced to smoke. There is an element of behavioral decision-making involved. So to compare the sale of tobacco to "crimes against humanity" is an injustice to the many victims of actual crimes against humanity who did not play any role in their persecution.

In addition, many entities played a role in the tobacco epidemic. Should the owners of convenience stores which actually sold the cigarettes also be prosecuted for crimes against humanity? What about the government officials who accepted tobacco industry contributions and voted against policies to regulate cigarettes? How about the publishers of magazines that advertised cigarettes and the producers of movies who accepted money to depict branded cigarettes? The list goes on.

But there is a particularly ironic aspect to the rest of this story. It could be argued that Professor Mackay herself has helped to protect cigarette sales. How? Well, she supported a ban on nicotine-containing electronic cigarettes in Hong Kong. So apparently, she is OK with the youth and adults in Hong Kong purchasing deadly tobacco cigarettes but she doesn't want them to be able to buy much safer tobacco-free alternatives that could save their lives.

Moreover, Professor Mackay has publicly claimed that smoking may be no more hazardous than vaping. As recently as last May, she wrote a widely publicized op-ed in which she claimed that: "There have been signs that increasing numbers of young people are taking up vaping thinking that it is a less harmful alternative to smoking even though science is far from conclusive on this presumption."

So what she is saying is that we don't know for sure that smoking is any more hazardous than using a completely tobacco-free product that involves absolutely no combustion and which has no significant known chronic health effects. If this doesn't undermine the public's appreciation of the severe hazards of smoking, then I don't know what does. Furthermore, this is exactly the kind of false propaganda about the hazards of smoking that we have condemned the tobacco industry for spewing.

On top of this, her organization - the World Lung Foundation - has spread false information about vaping, claiming that it is a gateway to smoking. In fact, the World Lung Foundation disseminated the conclusion that e-cigarettes are a gateway to smoking based on a barely comprehensible quote of a single kid in Fife.

Hyperbole is often acceptable to make a point. But not when it involves placing individuals in jail or being insensitive to the victims of horrible human rights violations.

Without Evidence, NIH Director Claims E-Cigarettes Cause Respiratory Infections and Asthma

In a commentary by the director of the National Institutes of Health (NIH), it is claimed that electronic cigarettes cause respiratory infections and asthma. According to the NIH director:

"E-cigarettes come with their own health risks, including lung inflammation, asthma, and respiratory infections."

The Rest of the Story

There is clinical evidence that vaping causes lung inflammation, so that part of the statement is supported by evidence. Specifically, vaping can cause lung irritation, leading to short-term increases in airway resistance as measured by sensitive technology, although not apparent by routine spirometry. Whether this acute irritation has consequences for the risk of actually developing chronic respiratory disease is not known.

However, when it comes to the claim that e-cigarettes cause asthma and respiratory infections, the story is quite different.

There is no clinical or epidemiological evidence that e-cigarettes cause either asthma or respiratory infections. There is one cell culture study which found an increased susceptibility to infection of respiratory epithelial cells. However, there is not a single clinical or epidemiological study I am aware of that documents an increase in the risk of respiratory infection due to vaping. Nor is there a single clinical or epidemiological study that documents an increased risk of asthma due to vaping.

In fact, on the contrary, there is evidence that switching from smoking to vaping actually decreases asthma symptoms and improves lung function and that it may reduce the risk of respiratory infections and pneumonia. Moreover, propylene glycol - the excipient in most e-liquids - is known to have bactericidal properties. In one study, smokers who switched to vaping reported a decreased incidence of respiratory infections.

That vaping can cause respiratory irritation is a fact. But the claim that vaping causes asthma and respiratory infections is what in today's lexicon might be referred to as an "alternative fact."