October 5, 2018, by NCI Staff
The most commonly used types of e-cigarettes among teens may deliver very high levels of nicotine, a new study has found.
In the study of adolescents who regularly used pod-style e-cigarettes, such as the brand Juul, researchers found that recent users had higher levels of nicotine in their bodies than have previously been found in adolescents who regularly smoked conventional cigarettes.
The study’s findings are concerning for several reasons, explained Rachel Grana, Ph.D., M.P.H., of NCI’s Tobacco Control Research Branch (TCRB), who was not involved with the study. One is the high potential for youth exposed to nicotine to become addicted.
“Early addiction has been linked to the continued use of nicotine-containing products, so it may be a lifetime problem if they start during adolescence,” Dr. Grana said. The potential for these products to deliver high doses of nicotine is another concern for this age group, she added.
Nicotine is thought to have damaging effects on the developing brain, explained Maciej Goniewicz, Ph.D., Pharm.D., of Roswell Park Comprehensive Cancer Center, who led the study. These effects may include impairment of memory and attention. Other chemicals in e-cigarettes, such as the flavoring additives they can contain, may also be hazardous but have yet to be studied in depth, he added.
“As these products have become more popular, there’s been a widespread recognition of the potential dangers,” said Dr. Grana. “This study really highlights some of the reasons for these concerns.”
The study results were published in Tobacco Control on September 7.
Measuring Nicotine Exposure
Pod-type e-cigarettes have skyrocketed in popularity over the last several years. Just one brand—Juul—now makes up about 70% of the e-cigarette market in the United States, according to recent consumer data, said Dr. Grana.
Pod systems differ substantially from earlier generations of e-cigarettes, Dr. Goniewicz explained. Earlier products used electricity to heat a cartridge of liquid, which usually contained nicotine in a so-called free-base form. This form of nicotine can cause a harsh sensation when inhaled, which may make it unappealing to young users, he added.
In contrast, pods work by vaporizing nicotine salts—a compact substance that allows the pods to be made small enough to fit in the palm of a hand. Nicotine salts are known to quickly deliver a high concentration of nicotine to the body without an unpleasant, harsh sensation. Dr. Goniewicz and his colleagues wanted to get an idea of how products incorporating these salts might be affecting young users.
They recruited 506 young people aged 12–21 who visited one of three outpatient clinics in Long Island, New York, in 2017 or 2018. All study participants completed an anonymous questionnaire about their use of e-cigarettes and other tobacco products. They also provided a urine sample.
Thirty-eight of the participants reported that they used pods daily or on some days and did not smoke conventional cigarettes. Their exclusive use of pods was confirmed by testing their urine samples for a biomarker of tobacco combustion.
The pod users had evidence of high levels of nicotine in their body. The median concentration of cotinine, a molecule that is formed during the breakdown of nicotine, in the participants’ urine samples was more than 50% higher than the urinary cotinine levels reported in a previous study of youth tobacco smoking.
The researchers also performed lab tests to measure nicotine outputs from the pod products that were used by participants. They found that 10 puffs from each of the pod products contained considerably more nicotine than 10 puffs from earlier-generation e-cigarettes.
“These [pods] are highly effective nicotine delivery systems,” said Dr. Goniewicz.
Reducing the Dangers
The study coincides with a growing national concern about e-cigarette use among adolescents and young adults. “Since 2011, use has increased dramatically among youth, with a spike in 2014 and 2015 to about 16% of high school students,” said Dr. Grana.
“[E-cigarettes are] by far the most commonly used class of tobacco product among youth,” she added.
Selling e-cigarettes to people under the age of 18 is illegal. But until recently, many websites that sell these products have not performed rigorous age verification for online purchases. Some have recently implemented stricter verification, said Dr. Goniewicz, but others have not. Many brick-and-mortar stores are also lax about verifying the age of customers who purchase e-cigarettes. And some minors get the products from older peers who can buy them legally, he added.
Last month, the Food and Drug Administration (FDA) announced a crackdown on the sale of e-cigarettes to minors. The agency issued more than 1,300 warning letters and fines to retailers who illegally sold e-cigarette products, including pods, to minors.
FDA also issued warning letters to the manufacturers of the five top-selling brands of e-cigarettes, requiring them to explain to the agency within 60 days how they plan to limit youth access to their products.
The letters explained that failure to submit a plan or submission of a plan that the agency considers to be inadequate may force FDA to revisit whether a company can legally sell their products in the United States.
An Unacceptable Tradeoff
Although some believe that e-cigarettes may help adult smokers quit using conventional cigarettes—products that contribute to almost half a million deaths every year—the evidence to support this view is limited, explained Michele Bloch, M.D., Ph.D., chief of TCRB.
“I still believe … that there are opportunities to move adult smokers down that ladder of harm” using e-cigarettes, said FDA Commissioner Scott Gottlieb, in a statement that accompanied the enforcement actions. But “FDA won’t tolerate a whole generation of young people becoming addicted to nicotine as a tradeoff for enabling adults to have unfettered access to these same products,” he added.
The new enforcement actions are being accompanied by an expansion of an educational campaign called The Real Cost, which aims to explain the dangers of e-cigarettes to youth nationwide.
“Research shows that kids don’t understand addiction very well,” said Dr. Grana. The new campaign, she added, “focuses on getting rid of the ‘cost free’ mentality; focusing on the fact that e-cigarettes are not harmless and that there are real costs [to youth] to using the product.”