The number of middle and high school students who say they've used e-cigarettes has tripled in just one year, according to new research that underscores health experts' fears about the growing popularity of these nicotine delivery devices among adolescents.
About 660,000 high school students reported using e-cigarettes in 2013, but in 2014, that number increased to about 2 million, according to a study published today as part of the Center for Disease Control and Prevention's Morbidity and Mortality Weekly Report.
And in middle school students, that number went from 120,000 to 450,000, the report said.
"This level of increase in such a short time period is alarming and unprecedented," study co-author Dr. Brian King told ABC News.
King is the deputy director of research translation for the CDC's Office on Smoking and Health.
"There is currently a wild, wild west in the manufacturing of e-cigarettes, with no standard for the manufacturing, sale or distribution of these products," he said.
E-Cig Makers Fuming Over CVS Tobacco Ban
UN Health Agency Urges Crackdown on E-Cigarettes
King, along with researchers at the CDC and the Food and Drug Administration, drew their conclusions by analyzing data from the National Youth Tobacco Survey, which is administered annually to middle and high school students across the country.
They also found that between 2011 and 2014, one in four high school students and one in 13 middle school students used a "tobacco product," which includes e-cigarettes, cigarettes, cigars and hookahs, the authors wrote. E-cigarettes were the most commonly used, they said.
The popularity of e-cigarettes, or electronic cigarettes, has spawned a multibillion-dollar industry and these devices are now the most commonly used nicotine product among middle and high schoolers, according to King's study.
E-cigarettes work by vaporizing liquid nicotine into an inhalable form. The liquid nicotine in e-cigarettes still contains carcinogenic materials, but in lower amounts than cigarettes, according to a 2013 study published in the British Medical Journal.
No federal restriction of e-cigarette sales to minors currently exists. The FDA proposed a rule last year which would open the door to such regulation, but this rule has not been finalized. Currently, there are eight states that still permit the sale of e-cigarettes to minors.
In response to today's CDC report, Thomas Kiklas, of the Tobacco Vapor Electronic Cigarette Association, said the e-cigarette industry supports restricting minors' access to the devices. Kiklas further noted that "there are no sales or marketing of products to minors of any tobacco products."
The products have, however, enjoyed advertisement on television and radio, as well as celebrity endorsements -- a fact that Dr. Edwin Salsitz, a chemical dependency expert at Mount Sinai Beth Israel, said may be responsible for the growing popularity among adolescents.
"Becoming physically dependent on nicotine is not benign for anyone but certainly not benign for an adolescent developing brain," Salsitz said.
Doctor's take:
While e-cigarettes may not contain all of the same cancer-causing agents as traditional tobacco products, they do still deliver nicotine -- a tremendously addictive chemical. The fact that exposure to nicotine could set up a lifetime of addiction is all the more reason that parents should be vigilant -- and talk to their kids about the risks of these trendy devices.
Dr. Michelle Jamison is a medical resident embedded with the ABC News Medical Unit. Doctor's Take blogs explain the latest studies while offering residents' medical opinions.