Introduction to E-Cigarettes

In the long-ago and far-away time of 2018, most parents couldn’t recognize a JUUL e-cig or knew that JUUL pods contain nicotine but, with the recent surge of news stories about kids, vaping, and health risks like E-cigarette or Vaping Associated Lung Injury (EVALI), it’s definitely time to pay attention. The CDC, FDA, and the National Cancer Institute estimate that in 2018, 27.1% of high schoolers and 7.2% of middle schoolers had used e-cigarettes, which totals about 3.6 million kids in the US. This number has risen to 5 million in 2019 (estimates are based on the FDA’s National Youth Tobacco Survey data). Given the widespread use of vaping devices by kids and the recent rise in EVALI, health risks from vaping are a growing concern for parents. In this series of posts, we will provide an introduction to e-cigarettes for parents, answer the most common questions about health risks like EVALI, the toxicology of vaping, and the history of vaping and vaping regulation.

Aside from addiction and other health risks, kids who vape are potentially at risk for EVALI (which you may have seen referred to as VAPI, VALI, EVAPI, or e-cigarette related lung illness). Of the over 1600 cases of EVALI that have been diagnosed in 2019 (the only year we have data for), 80% were younger than 35 years old, and 15% were under 18 years old. Cases of EVALI are widespread, with documented cases in 49 states, Washington D.C., and the The Virgin Islands. In early November 2019, the CDC linked Vitamin E acetate to all of the tested 29 EVALI cases, but they caution that they cannot yet rule out that other chemicals could be contributing to the EVALI outbreak.

What are e-cigarettes? What is vaping? 

The National Institutes of Health defines e-cigarettes or electronic cigarettes as “battery-operated devices that people use to inhale an aerosol, which typically contains nicotine (though not always), flavorings, and other chemicals.” E-cigarettes are fast-changing products, available in an ever-increasing variety of shapes and sizes. JUUL is the most popular brand used by kids and young adults alike, occupying about 70% of the market share in 2018. These devices can look like cigarettes, large metal or plastic boxes, pens, USB drives, watches, and even hoodies, which makes them all too easy to conceal from parents.

Examples of commonly used e-cigarettes and vaping devices
(Left) Closed system pods are a new generation electronic cigarette. These are five of the most commonly used from right to left: Juul, Von Erl, Juno, and Phix. Image by Sarah Johnson, Wikimedia Commons
(Middle) A Juul electronic cigarette, with four ‘pods’ (one loaded and three next to it). Image by Fair Expert, Wikimedia Commons
(Right) Other types of e-cigarettes. Image by California Department of Public Health

E-cigarettes generally contain several common components: a tank or pod that holds the e-liquid, a battery, and a heating element that aerosolizes the e-liquid. The term vaping is actually a misnomer, as the heating element does not vaporize the liquid. In fact, the use of this term has created a common misconception that vaping merely creates a harmless “water vapor”. However, these devices actually create an aerosol, which contains more than just water vapor, including known toxic chemicals and hazardous particles. 

What chemicals are in e-liquids?

In addition to nicotine, e-liquids (also called e-juice, vape juice, or vape liquid) typically contain: 

  • liquid propylene glycol (PG), vegetable glycerin (VG) or both PG and VG,  to help the aerosol form
  • flavoring compounds
  • sometimes other unintended chemical contaminants

The aerosol, that results from heating the e-liquid, has been found to also contain:

  • toxic heavy metals, such as lead or cadmium
  • cancer-causing chemicals
  • other ultrafine particles

All of these make their way into the e-cigarette ‘vapor’ or aerosol, which users then inhale directly into their lungs. The inhalation of these chemicals can directly affect lung health

Graphic showing components of e-liquids
Components of e-liquids.
Image from CDC

Contrary to a popular misconception about e-cigarettes, all JUUL products contain nicotine, the addictive chemical commonly found in cigarettes. In fact, the amount of nicotine in one standard JUUL pod (5% nicotine) is roughly equivalent to 1 pack (20 cigarettes) worth of nicotine. Worse, some other e-cigarettes have been known to contain even more nicotine, depending on their formulation. This misconception about JUUL not containing nicotine is fairly widespread. In one study, researchers found that 63% of JUUL users said they were unaware that this brand of e-cigarettes always contains this addictive chemical. 

In addition, since these e-cigarettes aren’t regulated (which we will discuss in a later post), some products are marketed as ‘nicotine-free’ even though they actually contain nicotine. For example, one study found 40% of e-cigarette users who reported using ‘nicotine-free’ products had nicotine metabolites in their urine. Other companies are starting to market similar-looking e-cigarettes that, in addition to nicotine, can also sometimes contain marijuana- or hemp-based chemicals.

Who uses e-cigarettes?

There are two main groups of e-cigarette users: adult smokers who use e-cigarettes to quit smoking and non-smokers for whom e-cigarettes serve as their first exposure to nicotine. According to the CDC’s 2015 National Health Interview Survey:

“In 2015, 3.5% of U.S. adults were current e-cigarette users. Among adult e-cigarette users overall, 58.8% also were current cigarette smokers, 29.8% were former cigarette smokers, and 11.4% had never been cigarette smokers. Among current e-cigarette users aged ≥45 years, 98.7% were either current or former cigarette smokers, and 1.3% had never been cigarette smokers. In contrast, among current e-cigarette users aged 18–24 years, 40.0% had never been cigarette smokers.”

In other words, while most adult e-cigarette users use both cigarettes and e-cigarettes or have replaced cigarettes with e-cigarettes, younger users are more likely to only use e-cigarettes and to not have previously used nicotine.

In the US, kids are more likely to use e-cigarettes than adults.  As of 2019, 5 million young people reported e-cigarette use. JUUL became the most popular e-cigarette among kids, likely because it does not generate a large ‘vapor’ cloud, making it easier to use in school and in public without being detected. It also contains a form of nicotine that tastes less harsh than cigarettes. The less harsh taste prevents the instinct to cough that is common with cigarette use, and allows users to inhale higher levels of nicotine. Thanks to the continuous availability of e-liquid, users can also vape in more continuous short bursts than finite periods of cigarette smoking. Consequently, there is no “end” to an e-cigarette like there is with cigarettes. All of this has contributed to a worrisome increase in the number of young vapers. 

2019 E-Cigarette Data: FDA and CDC released findings from the 2019 National Youth Tobacco Survey. The results show disturbing rates of e-cigarette use among both middle and high school students in 2019, with more than 5 million youth reporting having used e-cigarettes in the past 30 days and nearly one million reporting daily use. While cigarette smoking is at an all-time low among high school students, increases in e-cigarette use have reversed progress made in the decline of overall youth tobacco use. (Download PDF)

E-cigarettes were first marketed as a smoking cessation device but, due to the slow regulatory process, they have not been approved by the FDA specifically for this purpose, as is required for other tobacco and nicotine-containing products marketed as smoking cessation devices. Unfortunately for adults using e-cigarettes to quit smoking, these devices do not seem to be effective. For example, a recent review of multiple studies suggests that people who try to use e-cigarettes to quit smoking tend to replace the nicotine in cigarettes with nicotine in e-cigarettes, rather than truly reducing nicotine addiction and use. 
Another study of adults who quit cigarettes found that after one year, 80% of people who had switched from cigarettes to e-cigarettes were still using e-cigarettes as compared to the 9% of people who switched to other nicotine cessation products that are still using those products. So, while e-cigarettes might be effective for quitting cigarettes, they do not seem to be effective for quitting nicotine, which is both toxic and highly addictive.

What are the potential risks?

While scientists have just begun studying vaping-specific health risks, it is clear that many of the risks of smoking are also relevant to vaping. Just like cigarettes, e-cigarette use comes with plenty of risks, including nicotine addiction, lung injury, cardiovascular issues, and effects on brain development. Since the evidence shows an increasing number of kids are vaping these days, it’s critical that parents pay attention. 

In our next post, we will focus on E-cigarette or Vaping Associated Lung Injury (EVALI).


Smoking cessation programs

While there are no FDA approved smoking cessation tools for youth, there are options like texting services and apps, including SmokefreeTXT and quitSTART App

There are also new e-cigarette specific tools via the Truth Initiative, including the text-based service, This is Quitting, (text “DITCHJUUL” to 88709) and a comprehensive program through the Mayo Clinic: BecomeAnEx ®. 

About the authors

Meghan E. Rebuli, PhD is an Assistant Professor in the Department of Pediatrics, the Center for Environmental Medicine, Asthma and Lung Biology, and the Curriculum in Toxicology & Environmental Medicine in the School of Medicine at the University of North Carolina at Chapel Hill.  Dr. Rebuli is actively engaged in clinical research on the effects of e-cigarettes on respiratory toxicology and has several related publications.

Radhika Dhingra, PhD is an Assistant Professor in the Department of Environmental Sciences and Engineering in the Gillings School of Public Health at the University of North Carolina at Chapel Hill.  Dr. Dhingra is interested in the public health implications of e-cigarette use and is collaborating on several e-cigarette research projects.