Are e-cigarettes really harmless?

This is the 4416th article of Da Yi Xiao Hu

Electronic cigarettes (e-cigarettes) are electronic devices powered by batteries that convert a mixture of nicotine and other ingredients into aerosols that are then inhaled by the user. Electronic cigarettes consist of batteries, atomization components, cartridges containing tobacco oil, and mouthpieces. In addition to typical electrically heated atomizing electronic cigarettes, there are also electronic cigarettes that use ultrasonic atomization devices instead of heating wires.

Many young people think that so-called e-cigarettes are very fashionable and do not smell pungent. Some even secretly think that the smoke produced by e-cigarettes has a lot of artificial fragrance, which is more fun than incense. In the seemingly "fairyland", do you really know what kind of demons and monsters you are inhaling?

Electronic cigarettes contain a variety of harmful substances, roughly estimated to contain polycyclic aromatic hydrocarbons, nicotine, volatile organic compounds, ultrafine particles, metals and silicates, etc.

First, let's talk about the familiar yet unfamiliar "main culprit" - nicotine, also known as nicotine . It is the main bioactive ingredient in e-cigarettes and the main substance that makes smokers addicted. Nicotine is neurotoxic and has obvious harm to the underdeveloped brain, especially for fetuses and adolescents. Long-term exposure can lead to increased release of catecholamines in the body and produce a variety of adverse cardiovascular reactions, affecting fat and sugar metabolism, and further leading to cardiovascular, pulmonary and cerebrovascular diseases in adults.

So what other unique “secret weapons” do e-cigarettes have?

This brings us to the "drug lord" - smoke aerosol . In addition to nicotine, electronic cigarette smoke contains harmful substances such as polycyclic aromatic hydrocarbons, volatile organic compounds (VOCs), ultrafine particles, metals and silicates, and even carcinogens such as formaldehyde. For example, short-term excessive exposure to 1,2-propylene glycol (PG) and propylene glycol (VG) in electronic cigarette aerosols can cause inflammation in the alveoli, and inhaled PG can also cause liver and kidney toxicity. Low molecular weight aldehyde and ketone compounds (formaldehyde, acetaldehyde, etc.) in smoke aerosols have a strong irritating effect on the respiratory system and can cause cancer. The carbonyl compound "2,3-butanedione" can cause respiratory inflammation, such as "popcorn lung" damage. Smoke aerosols are cytotoxic, and cytotoxicity refers to the ability to cause DNA damage and cell death. Some studies believe that e-cigarette-related lung damage is closely related to it. The clinical manifestations of e-cigarette-related lung damage include infiltrative lesions in the lungs, diffuse alveolar hemorrhage, allergic pneumonia, organizing pneumonia, and severe acute asthma attacks, etc.

Do you know the "fox spirit" in e-cigarettes that confuses everyone - flavoring additives? Since the launch of e-cigarettes, in order to lure and attract young consumers, the number of flavoring additives related to e-cigarette products on the market has once reached more than 16,000. The ingredients include cinnamaldehyde, menthol, benzyl alcohol, vanillin, eugenol, etc. Although they can be eaten, inhaling them is another matter. They damage not only lung epithelial cells, but also fibroblasts, can cause oxidative stress, and the toxicity doubles after multiple mixtures.

Because tobacco-specific nitrosamines, tobacco alkaloids, flavoring ingredients and other additives contain a large number of toxic and harmful substances in smoke aerosols, it is not just "water vapor" as many marketing propaganda claims. When using electronic cigarettes, the metal elements in the components can be released into the smoke oil after being heated, and then enter the user's body with the electronic cigarette smoke. Long-term intake of metals can cause a variety of diseases. Metals such as nickel, chromium, cadmium, tin, aluminum and lead are potential carcinogens. They are related to the occurrence of tumors such as lung cancer, sinus cancer and oral cancer, and can also cause diseases such as chronic periodontitis.

E-cigarettes also produce secondhand smoke, which is a new source of air pollution. Compared with the air in a smoke-free environment, the average concentration of PM2.5 in e-cigarette smoke is 6 to 86 times higher, the concentration of polycyclic aromatic hydrocarbons increases by 20%, the aluminum content increases by 2.4 times, the nicotine content increases by 10 to 115 times, the acetaldehyde content increases by 2 to 8 times, and the formaldehyde content increases by 20%, exceeding the highest recommended level specified in the guidelines of the World Health Organization (WHO) Framework Convention on Tobacco Control. The content of certain metals (such as nickel and chromium) in e-cigarette secondhand aerosol is even higher than that of secondhand smoke produced by cigarettes, and the aerosol particles are smaller, which has a greater impact on health.

In 2021, the "China Smoking Hazards Health Report 2020" added the "Health Hazards of Electronic Cigarettes" chapter for the first time. This "invisible killer" in a fashionable coat - electronic cigarettes is increasingly worthy of people's vigilance, especially the impact on the younger generation. Electronic cigarette filling liquids of various flavors or brands and their aerosols are more addictive and harmful than traditional cigarettes. Electronic cigarette aerosols contain highly oxidized free base nicotine, so adolescents and young adults who use nicotine-containing electronic cigarettes are more likely to become addicted to nicotine. Compared with adults, young people experience nicotine withdrawal symptoms earlier and more frequently, including headaches, irritability, difficulty sleeping, difficulty concentrating, and increased appetite. In September 2022, tobacco disease experts from the Respiratory Disease Specialty Branch of the Shanghai Medical Association jointly wrote an article entitled "Health Hazards and Countermeasures of Electronic Cigarettes", which reviewed the relevant literature on electronic cigarettes in recent years and explained the composition of electronic cigarettes and their health hazards. The use of e-cigarettes may reduce the use of traditional cigarettes to a certain extent, but it does not really free traditional cigarette users from nicotine dependence. On the contrary, it can maintain e-cigarette users' dependence on nicotine, allowing smokers to continue using e-cigarettes or traditional cigarettes, or even become dual users of e-cigarettes and traditional cigarettes.

From October 1, 2022, the mandatory national standard for e-cigarettes will be officially implemented, and the sale of flavored e-cigarettes other than tobacco flavors will be completely banned. On October 28, 2022, the "Shanghai Regulations on Smoking Control in Public Places" was amended: Tobacco control refers to taking effective measures to prohibit smoking (including e-cigarettes) in non-smoking places specified in these regulations. China has taken "tough measures" in tobacco control, especially e-cigarette control!

It was said in "Zuo Zhuan·Xuan Gong San Nian": "No evil spirits or monsters can be encountered." Now that the fact that e-cigarettes are harmful to health has been pointed out, the evil spirits and monsters among them have nowhere to hide in broad daylight, making health more and more visible!

References

[1] Wang Chen, Xiao Dan, Chi Hui. Summary of “China Smoking Health Report 2020”[J]. Chinese Journal of Circulation, 2021, 36(10): 937-952.

[2] Tobacco Disease Group, Respiratory Branch, Shanghai Medical Association. Health hazards and countermeasures of e-cigarettes[J]. Chinese Journal of General Practitioners, 2022, 21(09): 817-825.

[3] Announcement on the approval and release of the mandatory national standard for electronic cigarettes[J]. China Standardization, 2022(09):235.

[4] Huang Yu. E-cigarette industry faces strict regulation[N]. Workers Daily, 2022-06-11(002).DOI:10.28277/n.cnki.ngrrb.2022.004075.

[5] Decision of the Standing Committee of the Shanghai Municipal People's Congress on amending the "Shanghai Regulations on Smoking Control in Public Places" and other five local regulations and abolishing the "Shanghai Regulations on Enterprise Name Registration and Management" [N]. Jiefang Daily, 2022-11-03(011).

Author of the popular science article: Shanghai Putuo District Central Hospital

Department of Respiratory and Critical Care Medicine

Popular science illustration: Primary school in Xinzhuang Town, Minhang District, Shanghai

Zhu Hanyi, Class 10, Grade 5