Efforts to stop young people vaping may backfire and lead to an increase in youth cigarette smoking, according to a new working paper.

Published in the National Bureau of Economic Research, the study suggests laws banning under 18s from buying e-cigarettes pushes youth toward smoking conventional cigarettes.

According to the study's authors, Minimum Legal Sale Age laws increase the cost of obtaining e-cigarettes as teens have to spend more time and effort obtaining vapor products or paying a third party extra to buy them for them.

Because e-cigarettes act as substitutes for other tobacco products, making it more difficult to obtain e-cigarettes may lead consumers to substitute vaping for smoking, leading to a worse public health outcome to the one intended.

Indeed, high-schoolers can often find regular cigarettes easier to obtain than e-cigarettes, even though the price in stores for regular smokes is actually higher.

The study's findings show MLSA laws increased youth smoking participation by 0.7 to 1.4 percentage points. Approximately half of the increase was attributed to smoking initiation, with the other half possibly coming from smokers continuing to smoke rather than using e-cigarettes to quit due to the restrictions.

"Taken together, our findings suggest a possible unintended effect of e-cigarette MLSA laws—rising cigarette use in the short term while youth are restricted from purchasing e-cigarettes," the authors write.

The unintended consequence of these laws is particularly concerning from a health standpoint, as the risks associated with vaping are unlikely to exceed 5 percent of those of smoking, according to the Royal College of Physicians.

"In sum, results from our study suggest that it is unclear if e-cigarette MLSA laws have a positive impact on public health," the authors conclude.

The paper follows three previous studies that examine the effect of MLSA laws on teen smoking. Two of the previous three studies found these laws led to an increase in teen smoking while one found the reverse.

States began introducing MLSA laws back in 2010. By the time the Food and Drug Administration deemed e-cigarettes tobacco products and introduced a minimum age for e-cigarette purchases of 18 nationwide, only two states were operating without a minimum vaping age.

The paper is the most significant work done yet on the consequences of MLSA laws and serves as a cautionary tale to lawmakers across the country who are debating whether to raise the vaping age to 21.

Both Hawaii and California, as well as 225 localities, have already implemented a minimum age of 21 for the purchase of vapor products. This has been done in tandem with raising the smoking age to 21.

There are many arguments for and against raising the smoking age to 21, but making it more difficult for young adults to obtain a vastly safer product in the form of e-cigarettes is another kettle of fish entirely and makes little sense from a public health standpoint.

"Preventing them from legally buying e-cigarettes until age 21 may harden preferences for cigarettes and make quitting at that age more difficult," the authors write.

The study emphasizes the need for more research into the effect of MLSA laws. But as the evidence stands, it would be foolhardy for legislators to jump the gun and treat e-cigarettes just as they would conventional tobacco and limit the opportunities for young people to switch to a vastly safer product by raising the age of purchase to 21.

Guy Bentley (@gbentley1) is a contributor to the Washington Examiner's Beltway Confidential blog. He is a consumer freedom research associate at the Reason Foundation and was previously a reporter for the Daily Caller.

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