Understanding Electronic Cigarettes and Their Users

Electronic cigarettes, commonly called e-cigarettes or vapes, are battery-operated devices that heat a liquid to produce an aerosol that users inhale into their lungs. These devices come in many different shapes and sizes, ranging from products that look like traditional cigarettes to those resembling USB flash drives, pens, smartphones, or even toys. The liquid inside, often called e-liquid or vape juice, typically contains nicotine, flavorings, and substances like propylene glycol and vegetable glycerin that help create the aerosol^[1].

When someone uses an e-cigarette, they draw on the device, which activates a heating element. This element warms the liquid until it becomes an aerosol—a mix of tiny particles suspended in air. Despite being commonly called “vapor,” this is not water vapor. The user inhales this aerosol into their lungs, and bystanders can also breathe it in when the user exhales^[1].

The term vaping refers to the act of using these devices. E-cigarettes are also known by various other names including vapes, vape pens, e-cigs, and electronic nicotine delivery systems or ENDS. Youth often use different terms to refer to these products or may call them by specific brand names^[1].

Epidemiology: Who Uses E-Cigarettes

E-cigarettes have been sold in the United States for nearly 20 years, but patterns of use have shifted dramatically over time. The introduction of newer devices that deliver higher levels of nicotine in an increasing variety of flavors led to a significant surge in youth use. In 2019, more than a quarter of high school students—27.5 percent—reported using e-cigarettes. This dramatic rise came four years after JUUL introduced a new nicotine delivery system along with aggressive online marketing campaigns that appealed to young people^[2].

While e-cigarette use among youth has declined since that peak, the numbers remain concerning. Currently, an estimated 1.63 million middle and high school students use e-cigarettes in the United States. E-cigarettes have become the most commonly used tobacco products among young people^[2][4].

The demographic patterns show that e-cigarettes are particularly attractive to younger age groups. Many students report that they started using e-cigarettes because friends used them. The devices often come in bright colors and are available in flavors that appeal to young people, such as fruit, candy, menthol, and mint. Some products have features similar to smartphones, with digital displays, games, and reward systems for vaping, which may make them even more appealing to youth^[1].

Worldwide, the concern about e-cigarette use among children and young people continues to grow. In many countries, rates of e-cigarette use among youth exceed adult use. Currently, 88 countries have no minimum age at which e-cigarettes can be purchased, and 74 countries have no regulations in place for these products at all^[7].

Causes: Why People Start Using E-Cigarettes

There are many reasons why people, especially youth, begin using e-cigarettes. One of the most significant factors is social influence. The most common reason students give for trying an e-cigarette for the first time is that a friend used them. Peer pressure and the desire to fit in with social groups play important roles in initiating use^[15].

Marketing and advertising also contribute to the uptake of e-cigarettes. These products have been aggressively marketed to young people through social media and influencers. The devices are designed with appealing aesthetics—some look like toys and games—and are available in at least 16,000 attractive flavors. Even brief exposure to e-cigarette content on social media is associated with greater intention to use these products and more positive attitudes toward them^[7].

Many young people and adults start using e-cigarettes believing they are safer than traditional cigarettes. Some adults who smoke turn to e-cigarettes hoping they will help them quit smoking, although no e-cigarette has been approved by the U.S. Food and Drug Administration as a smoking cessation aid^[3].

The availability of appealing flavors plays a significant role in why both youth and adults begin and continue to vape. The variety of flavors can make vaping seem more enjoyable and less harmful than it actually is^[15].

Risk Factors: Who Is Most Vulnerable

Several groups of people face higher risks from e-cigarette use. Youth and young adults are particularly vulnerable because their brains are still developing until about age 25. Using nicotine during these critical developmental years can harm the parts of the brain that control attention, learning, mood, and impulse control. This exposure can lead to long-term consequences including learning difficulties and anxiety disorders^[15].

Pregnant women represent another high-risk group. Nicotine exposure during pregnancy can adversely affect the development of the fetus. The consumption of nicotine can lead to negative impacts on the developing baby’s brain and overall health^[7]. Little research has been conducted into the safety of e-cigarettes and e-liquids during pregnancy, and it is not yet known whether the vapor itself is harmful to a baby^[17].

People who have never smoked or used other tobacco products should avoid starting to use e-cigarettes. These individuals have no reason to expose themselves to nicotine and the other potentially harmful chemicals found in e-cigarette aerosol. The devices should not be used by youth, young adults, or women who are pregnant^[3].

People with mental health conditions may also face increased risk. Many students who vape report that they use e-cigarettes because they feel anxious, stressed, or depressed. This is the most common reason students give for currently using e-cigarettes. However, nicotine addiction itself can harm mental health and become a source of stress. Nicotine addiction or withdrawal can contribute to feelings of stress, anxiety, and depression, or make these feelings worse, creating a harmful cycle^[15].

Individuals who engage in dual use—using both e-cigarettes and regular cigarettes—face particular risks. This pattern does not provide an effective way to safeguard health. Smoking even a few cigarettes a day can be dangerous, and dual use may result in greater exposure to harmful substances than using either product alone^[8].

Symptoms and Effects of E-Cigarette Use

Using e-cigarettes can lead to various symptoms and health effects. The most immediate concern is nicotine addiction. Nicotine is the addictive substance found in cigarettes and other tobacco products, and it is also present in most e-cigarettes. People who vape can become addicted to nicotine, which can make it very hard to quit^[8].

The particles inhaled while vaping can cause inflammation, which means swelling, and irritation in the lungs. This can lead to breathing problems and lung damage, including scarring and narrowing of the tubes that bring air in and out of the lungs. People who vape may experience coughing, shortness of breath, and chest tightness^[10].

E-cigarette aerosol is not harmless. While it generally contains fewer toxic chemicals than cigarette smoke, it still contains substances that can be harmful to both users and non-users who are exposed to the aerosol secondhand. The aerosol typically contains nicotine and other toxic substances. Some chemicals found in e-cigarette aerosol can cause cancer, including acetaldehyde and formaldehyde. Others are known to cause lung disease, such as acrolein, diacetyl, and diethylene glycol^[10][7].

Heavy metals like nickel, tin, lead, and cadmium have also been found in e-cigarette aerosol. Additionally, the aerosol contains tiny particles that can get deep into the lungs. The long-term effects of inhaling these substances are not yet fully understood because vaping has not been around long enough for researchers to study its long-term health impacts^[10].

There have also been reports of serious lung injuries associated with vaping. A condition called EVALI—e-cigarette or vaping product use-associated lung injury—has been linked to vitamin E acetate found in some vaping products. This condition can cause severe respiratory symptoms and has resulted in hospitalizations and deaths^[10].

Beyond physical symptoms, e-cigarette use can affect mental health and behavior. As mentioned earlier, nicotine can negatively impact brain development in young people, potentially leading to long-term problems with attention, learning, mood regulation, and impulse control^[15].

Prevention: Reducing the Risk of E-Cigarette Use

Prevention efforts focus primarily on stopping youth from starting to use e-cigarettes and helping current users quit. Parents, educators, and health care providers play crucial roles in protecting young people from the harms of vaping. They serve as trusted sources of information and can engage in meaningful conversations with youth about the dangers of vaping^[15].

One important prevention strategy is education. Young people need accurate information about what e-cigarettes contain and the real health risks they pose. Many youth mistakenly believe that vaping is harmless or that it is just “water vapor.” Correcting these misconceptions is essential. Educational campaigns should explain that e-cigarette aerosol contains nicotine, harmful chemicals, and heavy metals—not just flavored water^[3].

Teaching youth healthy coping skills offers another prevention approach. Since many students report using e-cigarettes to deal with feelings of stress, anxiety, or depression, providing alternative ways to manage these emotions can help prevent initiation or support cessation. Healthy coping strategies include recognizing and managing stressful feelings, practicing relaxation techniques like meditation or deep breathing, building a strong support system of family and friends, and engaging in self-care activities^[15].

Regulatory measures also play a role in prevention. Only people age 21 and over are allowed to buy e-cigarettes in the United States. However, enforcement of these age restrictions varies, and in many countries worldwide, no minimum age exists for purchasing these products. Strengthening regulations around marketing, sales, and product standards can help reduce youth access and appeal^[19][7].

Addressing the role of social media and marketing is critical for prevention. Limiting youth exposure to e-cigarette advertising and countering the influence of social media content that promotes vaping can help reduce the appeal of these products. Parents and educators can monitor children’s social media use and discuss the marketing tactics used by e-cigarette companies^[7].

For adults who smoke, understanding that dual use is not an effective harm reduction strategy is important. Using both cigarettes and e-cigarettes does not provide health benefits. If an adult who smokes chooses to try e-cigarettes to quit smoking, the goal should be complete substitution—stopping all cigarette smoking entirely^[8].

Pathophysiology: How E-Cigarettes Affect the Body

Understanding how e-cigarettes affect the body helps explain why they pose health risks. The process begins when the device heats the e-liquid to create an aerosol. This aerosol contains various substances that enter the body through the lungs. Unlike the digestive system, which can break down and filter many substances, the lungs provide a direct route for chemicals to enter the bloodstream^[5].

The main components of e-liquids typically include nicotine, flavorings, and humectants like propylene glycol and glycerol. While propylene glycol and glycerin are considered safe when consumed in food, their effects when inhaled as an aerosol and absorbed through the lungs are less well understood. When these substances are heated, they can undergo chemical changes that may produce harmful byproducts^[5].

Nicotine is a stimulant drug that affects the nervous system. When inhaled through vaping, nicotine quickly reaches the brain, where it triggers the release of chemicals that create pleasurable sensations. This rapid delivery to the brain is what makes nicotine so addictive. The health effects of nicotine are well documented when it comes from cigarette smoke, but much remains unknown about the specific health effects of nicotine when delivered as an aerosol^[5].

In the lungs, the inhaled particles can cause immediate effects. The particles trigger inflammation—the body’s immune response to what it perceives as a threat. This inflammation causes swelling and irritation of lung tissue. Over time, repeated inflammation can damage the delicate structures in the lungs, leading to scarring and changes in how well the lungs function. The tubes that carry air in and out of the lungs can become narrowed, making breathing more difficult^[10].

The flavoring chemicals in e-liquids, while often safe for eating, can be harmful when inhaled. Some flavorings contain a chemical called diacetyl, which has been linked to serious lung disease. Many of the thousands of flavoring constituents available have been thoroughly evaluated for safety when included in food, but their effects when they enter the bloodstream through the lungs are largely unknown^[5].

The heating process itself can create additional problems. When the e-liquid is heated by the battery-powered coil, the temperature can sometimes get high enough to cause chemical reactions that produce toxic substances. These may include formaldehyde and acetaldehyde, which are known carcinogens—substances that can cause cancer^[10].

The battery design and power output influence how hot the liquid gets and therefore what kinds of chemicals are produced. Different devices heat liquids to different temperatures, meaning the composition and potential harmfulness of the aerosol can vary significantly depending on the device and how it is used^[5].

In developing brains, particularly those of children and young adults, nicotine interferes with normal growth and function. The brain continues developing until about age 25, and nicotine exposure during this period can disrupt the formation of brain circuits that control attention, learning, and susceptibility to addiction. These changes may be permanent and can increase the likelihood of future substance use problems^[15].

While e-cigarettes do not produce tar or carbon monoxide—two of the most harmful elements in tobacco smoke—they are not without risks. The liquid and vapor contain potentially harmful chemicals, though generally at lower levels than found in cigarette smoke. Researchers continue to study how these chemicals affect the body over time, but definitive answers about long-term effects will require many more years of research^[17].