Smokers who switch to e-cigarettes might actually have a harder time giving up the habit than if they simply cut tobacco out of their lives altogether.
Currently advice from the United States Centers for Disease Control and Prevention (CDC) weighs in favor of giving electronic nicotine delivery systems products (yep, that's vapes) a go while trying to quit cigarettes for good.
The public health agency admits the evidence isn't sufficient, but it is 'suggestive', which can be enough for smokers in the US to give vaping a shot while trying to wean themselves from nicotine dependency.
But that advice could soon swing the other way as counter examples pile up, demonstrating there's less of a chance you'll be living smoke-free in the years to come if you swap out your tobacco for vaporized nicotine.
A recent study by researchers from the University of California San Diego in the US could tip the scales of evidence away from suggestions that vaping might be an effective stepping stone for quitting cigarettes.
"Quitting is the most important thing a smoker can do to improve their health, but the evidence indicates that switching to e-cigarettes made it less likely, not more likely, to stay off of cigarettes," says cancer researcher John P. Pierce.
While conventional forms of smoking burning tobacco products have dropped in recent years, the market for e-cigarette technology is booming. At least part of this shift appears to be fueled by smokers who want to quit, and feel vaping is a safer alternative that buys them time to make the jump to a nicotine-free life.
For now, the science supports claims that vaping comes with fewer health issues than cigarettes. Reducing the concentration of toxic material you're breathing in can only be a good thing, even if 'fewer' isn't the same as 'zero'.
But for any smoker who values their future health, the only goal worth having is kicking the habit for good.
And vaping, it turns out, isn't likely to play a role in that.
"Our goal in this study was to assess whether recent former smokers who had switched to e-cigarettes or another tobacco product were less likely to relapse to cigarette smoking compared to those who remained tobacco free," says biostatistician Karen Messer, a senior author on the study.
Messer and her colleagues assessed 13,604 participants who identified as established smokers between 2013 and 2015. Through use of annual surveys, the researchers tracked the volunteer's use of a dozen different tobacco products, collecting data on who continued to smoke, who vaped, and who'd quit altogether.
Importantly, they also made note of those who gave up, only to take up the habit again later.
In the first follow-up survey, just under one in ten established smokers had claimed to quit cigarettes. Of those 'former smokers', a little over a third switched to another form of tobacco use. In 22.8 percent of those cases, that other form was vaping e-cigarettes.
Those individuals were more likely to be white, wealthier, more dependent on smoking, and tended to see vaping as a safer option.
They also had more of a chance of going back to smoking cigarettes within the next 12 months.
Among those who ditched all tobacco products of any kind, half were still smoke-free after a year. For those who vaped, only 41.5 percent were successful.
"If switching to e-cigarettes was a viable way to quit cigarette smoking, then those who switched to e-cigarettes should have much lower relapse rates to cigarette smoking. We found no evidence of this," says Pierce.
Observational studies like these aren't without their shortfalls. Researchers effectively stand back and ask volunteers to share their habits, which leaves more room for interpretation than if it were a study under controlled conditions.
It's also a snapshot of a much larger pattern, one which could see more vapers quitting for good further down the track.
E-cigarettes are still relatively new as a cultural phenomenon, meaning it'll take time to gather necessary data to determine how it affects health and habits over the course of a lifetime. We're also discovering a litany of risks (including deadly ones) that are exclusive to vaping.
Still, we don't need to wait to know one thing with certainty – the best time to have that final cigarette is yesterday. On that, the science couldn't be more settled.
This research was published in JAMA Network Open.