I've found that of almost all of the topics I write about over my blog, the one that stirs up the most controversy, the one that generates me the most hate, the most emails and the most tweets, is e-cigarettes. Defenders of them are very passionate and surprisingly organized. Those that dislike them are no less dedicated, but let's get past the rhetoric. E-cigarettes are the topic of this week's Healthcare Triage.

(Intro)

We all know what cigarettes are, right? Tobacco rolled in a paper, lit on fire, and then inhaled, often through a filter. But all of that is a somewhat inefficient means of delivering nicotine to people. You inhale the drug, along with a ton of other crap in the smoke. E-cigarettes are different. Instead of using fire to burn tobacco, they vaporize liquid nicotine, which is then inhaled. You get almost the same hit of nicotine, but you get it through vapour instead of cigarette smoke. The e-cigarette market, only 7 years old now in the US, is about a billion dollars a year now. In 2011, more than 20% of Americans who smoked had tried e-cigarettes. That means that more than 5% of all adults in the country had tried it - kids too. Almost 7% of children in grades 6-12 tried e-cigarettes in 2012. Those who support them like them because they believe they're safer. They also think that they can be a means to help others quit smoking cigarettes. And if they're safer, that would be a good thing, right? But are those beliefs true? There's not as many studies on this topic as I'd like. A lot of them are flawed, and they often conflict with each other. For instance, a randomised, controlled trial published last year in the Lancet compared putting people on e-cigarettes, nicotine patches or placebo to quit smoking. At six months, 7.3% of those on e-cigarettes had quit, versus 5.8% with patches and 4.1% with placebo. But so many fewer people had quit than the researchers had anticipated that the difference seen wasn't statistically significant. But let's not cherry-pick. The American Heart Association published a systematic review of e-cigarette studies earlier this year, let's dig in to what they found. To the research!

One study found that the aerosols from 12 different brands of e-cigarettes contained fewer toxins from cigarette smoke in general, although they varied a lot. Other studies went further. Some looked at whether the nicotine fluid could be cytotoxic, or harmful to cells. Interestingly, it seemed that most of the cytotoxic effects were related more to additives to the liquid like flavoring, than to the nicotine itself. Studies of second-hand smoke with these cigarettes were similar. Yes, you get nicotine in the air, and yes, you can detect particulate matter. People who smoke e-cigarettes are not exhaling water vapour as many ads would like you to believe. But at this point all we have are lab studies. Those show that second-hand exposure to e-cigarettes probably means less exposure to nicotine than conventional cigarettes. But it's not as much of a difference for particulate matter. There's no carbon monoxide though, which is good.

But let's get to health. Some people will point to cigarettes and say they can cause fires or explosions, and e-cigarettes can cause those too. You may have seen a video on the internet. They can also cause throat and mouth irritation, nausea, vomiting, coughing, all of those things too.

Small studies showed that there can be short term pulmonary function changes after e-cigarette use, but these may be less severe than with tobacco cigarette use. Some studies show no change at all, but many of those are promoted by the industry or advocacy groups, and they're particularly flawed. The bottom line is that there's minimal evidence that they may be safer than tobacco cigarettes. But that doesn't mean that they have no negative effects at all. There's also pretty much no evidence at all to tell us about long-term effects.

And do they help people to quit smoking? There are five population-based studies: four longitudinal, one cross-sectional. Combining them in a meta-analysis led to a pooled odds ratio of 0.6, meaning that e-cigarette use was associated with a lower quit rate than not using them. That's not good. But it's important to recognize that these kinds of studies aren't randomised, and they didn't control for nicotine dependence. In other words, it could be that the most addicted people were the ones trying e-cigarettes and it's not the device's fault that they couldn't quit. So let's look at clinical trials, and there are four of them, including the Lancet one I already mentioned. Three of the others didn't have a control group that didn't use e-cigarettes, none added in behavioral support or other components that usually accompany smoking cessation intervention. This means we can't have a ton of confidence in them. The better trials didn't find any effects of e-cigarette use that were better than what we've seen in other smoking cessation interventions. In other words, there's no real evidence that they're better than nicotine replacement therapy or behavioral intervention.

Harm reduction is different. If e-cigarettes can get people to smoke fewer tobacco cigarettes then that might result in an improvement in health. There is some evidence that e-cigarettes may lead to people smoking less even if they don't quit. But we need more studies of good quality to see if this is really the case.

At this point the United States, specifically the FDA, doesn't regulate e-cigarettes at all. Some states do, but not the federal government. New rules have been proposed though to change that. If they go into effect, selling e-cigarettes to minors would be illegal, health warnings would be added, and selling them in vending machines would now be prohibited. Companies would be forced to detail their ingredients, allow the FDA to review their marketing plans, and they'd get to approve any claims about the benefits they might have. Online sales would still be legal, and they'd still be able to advertise on radio or TV, which tobacco can't do. Those rules were proposed in April, there's been no movement since.

In the EU on the other hand, e-cigarettes with nicotine concentrations up to that of a pack of cigarettes are regulated just like tobacco. If they have more nicotine than that, they're regulated like medical devices. But as of March, it appears that the regulations might get even tighter.

In the UK, things are a bit more permissive. E-cigarettes aren't covered by smoking bans, but legislation may be coming to bar their sales to minors.

So let's review. There's a reasonable case to be made that if all tobacco smokers converted to e-cigarette use there would likely be an overall health benefit. But the prevailing evidence shows that introducing e-cigarettes may lead to more dual smoking than quitting. And it may be getting new people to start smoking, which would be bad. It's not clear.

The stuff coming out of these cigarettes is probably not as bad as tobacco smoke, but it's not harmless water vapour either. And if they were marketed as quit aids and sold as such, I think fewer people would be concerned. But they're often sold as a healthy way to get the sweet, sweet benefit of nicotine. That's not too far off from the ways that cigarettes used to be sold. That makes a lot of people uncomfortable, and it's easy to understand why.