South Portland High School senior Grace Rende (left) and vice principal Kimberlee Bennett in front of the bathroom, the school's vaping hotspot. Credit: Patty Wight | Maine Public

A decades-long decline in American teen use of tobacco had been a positive story. But that trend has reversed, in large part because of the growing popularity of e-cigarettes.

While e-cigarettes, or vaping, may have benefits for former adult smokers, the teen trend is cause for alarm — and stronger regulations. While the federal government is considering a variety of new regulations on e-cigarettes, the most straightforward solution would be to raise the legal age for tobacco purchases to 21. Maine is among six states and hundreds of municipalities that have made this change.

E-cigarette use among high school students jumped 78 percent from last year to this year, according to the federal Food and Drug Administration. There was a 48 percent increase among middle school students.

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Last year, 21 percent of high school students nationwide reported using e-cigarettes in the past 30 days. That’s higher than the 15 percent of Maine high school students who reported using e-cigarettes.

In a national survey, 27 percent of high school students reported using tobacco in the past 30 days. That compares to 20 percent in 2017.

The increase is driven by growing use of vape cartridges that look like USB drives, which can be hidden from parents and school officials. They also have a high nicotine content and come in flavors that appeal to teens.

Federal officials have expressed concern that the increase in vaping among teenagers will lead to an increase in smoking.

“Research shows that, compared with non-users, youth who use e-cigarettes are more likely to transition to conventional cigarettes — risking a lifetime of addiction to smoking and resulting smoking-attributable disease,” the FDA and Centers for Disease Control warned in a November press release accompanying the survey results.

[Vaping reverses decline in tobacco use among Maine students]

The U.S. Surgeon General has concluded that e-cigarette use among youths and young adults is a public health concern because exposure to nicotine during adolescence can cause addiction and can harm the developing adolescent brain.

To combat these trends, the FDA is considering a ban on e-cigarette sales in convenience stores, where popular brands like JUUL and blu are currently sold. Sales are restricted to buyers over 18 in most states, but many retailers don’t check IDs for e-cigarette sales. The agency is also considering a ban on online sales, which is an easy, minimal first step.

Earlier this year, Maine raised its tobacco purchase age to 21. This includes e-cigarettes. However, people who turned 18 by July 1 are grandfathered and able to legally purchase tobacco products in the state.

One rationale for the change is that raising the age to 21 would have a significant effect on high school-age smokers and potential smokers, because their 18- to 20-year-old peers no longer would be able to legally purchase tobacco for them. Breaking this link for e-cigarette purchases makes sense as well.

Stricter regulations on e-cigarette sales and advertising are needed. But, so too, is more research about vaping.

E-cigarettes, which users fill with liquid containing nicotine and a flavor, are safer than cigarettes, which shorten the life expectancy of smokers by an average of 10 years. Tobacco-related illnesses are the leading cause of preventable death in the United States.

In 2015, Public Health England said that e-cigarettes are 95 percent safer than cigarettes. This prompted the Royal College of Physicians to endorse e-cigarettes as a valuable tool in helping people to quit smoking. In England, e-cigarettes are now the most commonly used anti-smoking aid.

At the same time, it does not appear that e-cigarette use is benign. The vapor contains potentially harmful chemicals, according to a 2014 FDA analysis. The dangers of the nicotine in e-cigarettes and the second-hand effects of e-cigarette vapor also need more study.

The new teen data adds urgency to the FDA’s challenge of restricting the availability of e-cigarettes to young people — who are at risk of using them as a gateway to cigarette smoking — while not limiting their availability to adults who can successfully use e-cigarettes to stop smoking.