An electronic cigarette (e-cigarette) is a device that heats liquid nicotine and flavorings so they can be inhaled. The use of e-cigarettes is often called “vaping,” because many people believe it produces a vapor. E-cigarettes create an aerosol composed of tiny particles, which is different from a true vapor.

E-cigarettes are known by many different names. This includes e-cigs, vapes, vape pens, electronic nicotine delivery systems (ENDS), alternative nicotine delivery systems (ANDS), e-hookahs, mods, vaporizers, and tank systems. E-cigarettes are also sometimes known by their brand names.

Vaping works by heating liquid inside a small device, which turns it into an aerosol that is then inhaled into the lungs. Unlike smoking, which burns tobacco, vaping heats liquid to release particles suspended in air. The aerosol contains nicotine, flavorings, and other chemicals. When inhaled from the mouthpiece, these particles travel down the throat and into the lungs.

E-cigarettes are available in many shapes and sizes. They can look like cigarettes, cigars, pipes, pens, and USB flash drives. Most types of e-cigarettes have:

• A cartridge, tank or pod that holds liquid (can be refillable).
• A heating element for turning the liquid into breathable particles (aerosol, commonly called “vapor”).
• A battery to power the heating element.
• A power or control button (some are activated by sensors when you inhale).
• A mouthpiece to breathe in the aerosol.

E-cigarettes don’t have tobacco, but many of them have nicotine, which comes from tobacco. E-cigarettes heat liquid to make an aerosol; cigarettes burn tobacco, which creates smoke. Because of this, the U.S. Food and Drug Administration (FDA) classifies them as "tobacco products."

Electronic cigarettes (e-cigarettes) were developed as a smoking cessation tool and a safer alternative to traditional cigarettes for people unable or unwilling to quit nicotine. The intention was to help people who smoke to reduce nicotine intake without exposure to the harmful tar and toxins in tobacco smoke, thus, reducing smoking-related diseases and deaths. However, 21 years since Chinese pharmacist Hon Lik, first introduced the modern e-cigarettes in 2003, to help himself quit smoking cigarettes, this did not work. He is now a dual user, both smoking and vaping. We must question whether they have achieved their intended objectives or if they have inadvertently become a Trojan horse in public health, presenting unforeseen risks and challenges.

Patterns of use

Some groups of adults use e-cigarettes at a higher percentage than others. For example:

• More men than women report current e-cigarette use.
• A higher percentage of young adults (18–24 years old) use e-cigarettes compared to older adults, usage declines with age.
• Use is higher among adults with less education, lower incomes, or without health insurance.
• Adults who identify as lesbian, gay, or bisexual report higher rates of use compared to heterosexual adults.
• Adults experiencing serious psychological distress are more likely to use e-cigarettes.

In 2024, e-cigarettes were the most used tobacco product among middle and high school students in the United States:

1. 63 million (5.9%) students currently used e-cigarettes. This includes:
   3. 410,000 (3.5%) middle school students.
   4. 21 million (7.8%) high school students.
2. Among students who had ever used e-cigarettes, 43.6% reported current use.
3. Among students who currently used e-cigarettes:
   38. 4% used an e-cigarette on at least 20 of the last 30 days.
   39. 3% used an e-cigarette every day.
4. 6% used flavored e-cigarettes. Vapes come in a variety of youth-friendly flavors, including fruit, candy, mint, and menthol.
5. Among students who currently used e-cigarettes; 55.6% used disposable e-cigarettes, 15.6% used prefilled or refillable pods or cartridges, and 7.0% used tanks or mod systems.

Most middle and high school students who vape both want to quit and have attempted to do so. In 2020, 63.9% of students who were current e-cigarette users reported wanting to quit, and 67.4% reported that they had tried to quit within the past year.

Why youth vape

Most tobacco use, including vaping, starts and is established during adolescence. There are many factors associated with youth tobacco product use. These include:

1. Tobacco advertising that targets youth: In 2021, 7 out of 10 U.S. middle and high school students reported exposure to e-cigarette marketing. Most students reported seeing e-cigarette advertisements or promotions in retail settings. Students also reported seeing advertisements on the internet, television, streaming services, movies, or in print media. In addition, about three out of four students (74%) who used social media reported seeing e-cigarette–related posts or content.
2. Product accessibility: Some e-cigarettes cost less than regular cigarettes, which may also contribute to youth vaping.
3. Availability of flavored products: A study from 2013–2015 showed that most youth who use e-cigarettes first start with a flavored variety. Availability of flavored vapes is among the top 10 reasons youth report ever trying an e-cigarette. In 2024, nearly 9 out of 10 middle and high school students who currently used e-cigarettes reported using a flavored product, with the most commonly used flavors being fruit, candy, and mint.
4. d) Social influences: The most common reason U.S. middle and high school students give for trying an e-cigarette is that a friend used them. Youth also report vaping because they are curious about e-cigarettes or because a family member used them.

Youth often obtain the e-cigarettes from others. Among U.S. middle and high school students who used e-cigarettes in 2021:

• 3% got them from a friend.
• 1% bought the products themselves.
• 7% had someone else buy the products for them.
• 7% had someone offer the products to them.

Dual use of e-cigarettes: Many young people who vape also use other tobacco products, including cigarettes and cigars. This is called dual use. In 2024:

• Among U.S. students who currently use a tobacco product, more than one-third report using more than one type of product, including 6%of high school students and 38.9% of middle school students.

Cannabis content of e-cigarettes: E-cigarettes can also be used to deliver other substances, including cannabis. In 2016, nearly one out of three (30.6%) of U.S. middle and high school students who had ever used an e-cigarette reported using marijuana in the device.

Health risks of E-cigarettes

The term “vapor” might sound harmless. But the aerosol that comes out of an e-cigarette is not water vapor, and it can be harmful. The aerosol from an e-cigarette can contain nicotine and other substances that are addictive.

1. Nicotine content: The e-liquid in most e-cigarettes has nicotine, the same addictive chemical in regular cigarettes, cigars, hookah, and other tobacco products. But nicotine levels are not the same in all types of e-cigarettes. Sometimes, product labels do not list the true nicotine content. There are some e-cigarette brands that have been found to contain nicotine even though they claim to be nicotine-free.

Young people can start showing signs of nicotine addiction quickly, sometimes before the start of regular or daily use. Because the adolescent brain is still developing, it is uniquely susceptible to nicotine.

The nicotine content of e-cigarettes has increased over time. Many e-cigarettes contain nicotine salts. These allow people to consume high levels of nicotine without experiencing the harshness of freebase nicotine.

High-nicotine products dominate US e-cigarette unit sales. In March 2022, products with a nicotine strength of 5% or more made up 81% of total e-cigarette unit sales. In recent years, the price of high-nicotine products decreased or stayed the same while the price of low-nicotine products increased.

2. Cancer risk: E-cigarettes contain chemicals that can cause cancer (carcinogens), like acetaldehyde and formaldehyde but their long term effect on cancer development is not yet clear.
3. Heart and lung disease: E-cigarettes contain chemicals known to cause lung disease, such as acrolein, diacetyl and diethylene glycol. A Johns Hopkins Medicine-led analysis of medical information gathered on a diverse group of almost 250,000 people over four years has significantly clarified the link between the “exclusive” use of e-cigarettes and chronic obstructive pulmonary disease, as well as high blood pressure in a sub-group of adults 30 to 70 years of age.

E-cigarettes and other similar products have been linked to lung problems. Using them can increase your risk of breathing problems. This includes worsening asthma symptoms, more frequent bronchitis, and lung infections.

The nicotine in e-cigarettes also increases heart rate, raises blood pressure, and might irritate blood vessels.

4. Vitamin E acetate, linked to lung injury caused by vaping (EVALI): An outbreak of EVALI in late 2019 and early 2020 put thousands of people in the hospital. At least 68 people died. Since then, EVALI cases have been declining, but people who vape can still get EVALI. Among people hospitalized with severe EVALI, most were younger than 35 and used THC-containing vapes from informal sources, such as online sellers or family and friends. However, EVALI can occur in anyone who uses either nicotine or THC-containing vapes.

Symptoms of EVALI included:

• Cough, trouble breathing, or chest pain
• Nausea, vomiting, or diarrhea
• Fatigue, fever, or weight loss

Some people had to be hospitalized, and some died from their illness. Some of these lung injuries were linked to products that were changed, including products that had vitamin E acetate. But there were also many EVALI cases that did not involve added vitamin E.

The number of EVALI cases has since dropped, but there are still people being diagnosed with EVALI. More studies are being done to look for other possible causes.

5. Heavy metals: E-cigarettes may contain heavy metals like nickel, tin, lead and cadmium which have been shown to have adverse health effects.
6. Tiny particles: E-cigarettes may contain tiny (ultrafine) particles that can get deep into your lungs passing the filtration system of the lungs.
7. Seizures: There have been reports of people having seizures after vaping. This has been reported most often in young people. These seizures are thought to be caused by nicotine, but more studies are being done.
8. Dental problems: Studies are also starting to show a link between e-cigarette use and damage to teeth and other oral tissues. This includes cavities in the teeth and irritation of gums and other membranes in the mouth.
9. Secondhand aerosol: E-cigarettes expose people to secondhand aerosol or vapor that can contain harmful chemicals. Scientists are still learning about the health effects of being exposed to secondhand e-cigarette aerosol. Secondhand aerosol can expose others to nicotine and possibly to other harmful chemicals.
10. Explosions: There have been reports of e-cigarettes exploding and causing serious injuries. The explosions are thought to be caused by faulty batteries or because the batteries were not handled as they should be.

Can e-cigarettes help people quit?

E-cigarettes are not approved by the FDA and European Medicines Agency as smoking cessation devices due to limited data on safety and effectiveness. This is because there is not enough research to show that they help people to stop using tobacco.

Recent research indicates that people who use both cigarettes and e-cigarettes have a higher risk of getting lung cancer than people who only use cigarettes. People should not use both products at the same time and are strongly encouraged to completely stop using all tobacco products.

Globally, regulation varies:

• 88 countries have no minimum purchase age.
• 74 countries lack regulations entirely.
• E-cigarettes are banned in about 35 countries.
• Others regulate them as consumer, pharmaceutical, or tobacco products.

Marketing frequently targets youth, with over 16,000 flavors, cartoon packaging, and sleek designs resembling toys or tech gadgets. Alarmingly, in many countries, e-cigarette use among adolescents exceeds adult use. Even brief exposure to vaping content on social media increases the likelihood of trying these products.

One of the greatest public health risks is that vaping could “re-normalize” smoking after decades of successful tobacco control. Smoking remains the leading preventable cause of death, killing more than 480,000 people annually in the United States alone.

Conclusion

Taken together, these findings show that no tobacco products, including e-cigarettes, are safe. Most e-cigarettes contain nicotine, a highly addictive substance that poses serious health risks, particularly for youth, pregnant women, and developing fetuses. In addition to nicotine, e-cigarette aerosol can contain harmful and potentially harmful substances, including cancer-causing chemicals and ultrafine particles that can be inhaled deep into the lungs. For these reasons, e-cigarettes should not be used by youth, young adults, or individuals who are pregnant. Moreover, e-cigarettes pose potential health risks not only to those who vape but also to others exposed to secondhand emissions, while placing an added burden on public health systems and government healthcare budgets. Compounding these concerns, the short- and long-term health effects of e-cigarette use remain unclear, and much is still unknown about their full impact on human health. Until more is understood, this evidence underscores the importance of prevention, education, and informed decision-making.

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