E-cigarette: A Cessation Solution or a New Gateway to Smoking Combustible Cigarettes

Background : Over the past decades, electronic cigarette (e-cigarette) has entered into the tobacco industry as a safe alternative to combustible cigarettes. The aim of the current study was to investigate the effects of e-cigarette on smoking cessation. Materials and Methods: Related studies were extracted by specific keywords from PubMed, ScienceDirect, and Scopus. The inclusion criterion was the relevance of the studies to the aim of the study from 2010 to 2022. Finally, the contents were summarized by content analysis. Results: Due to the non-combustible property of tobacco, many people consider it less harmful. Other features such as different flavors, availability, and modern appearance make it user-friendly. Nevertheless, numerous studies declared the harmful effects of e-cigarettes on the lungs, platelets, and vascular tissue because of the formation of new suspected toxic compounds. Moreover, it has been reported that the use of e-cigarettes not only does not contribute to smoking cessation but also increases people’s desire to conventional smoking, especially in e-liquids containing nicotine. Conclusion: The potential of e-cigarette as a safe tool for smoking cessation remains debatable. In addition, due to the greater attraction of young adults, countries should enact laws regarding the distribution, access, and prohibitions.

http://thj.hums.ac.ir http 30% reduction in smoking by 2025. WHO's MPOWER package consists of a set of six key strategies for fighting the tobacco epidemic. The smoking cessation approach by offering help to quit smoking is considered as one of the main components. Nicotine replacement therapy and psychological support are two methods used to quit smoking, but according to a study conducted in the European Union from 2012 to 2017, the use of pharmacotherapy and psychological support decreased from 14.6% to 11.1% and from 7.5% to 5%, respectively. On the other hand, another approach, which is the use of Electronic Nicotine Delivery System, has been developed, and its use has increased from 3.7% to 9.7% (10).
Electronic Nicotine Delivery System, also called e-cigarette, which was first introduced by Hon Lik in 2003, is an electronic device that delivers nicotine to the consumer through vapor inhalation without the combustion of smoke (11). E-cigarettes include a cartridge containing e-liquid, a heating element or atomizer to heat the e-liquid to produce a vapor, a sensor, a rechargeable battery, and a mouthpiece to suck the generated vapor. In some models, a microprocessor produces a red-orange light at the tip of the device and evokes the presence of fire at the tip of a cigarette (12).
The e-liquid in the cartridge, which contains humectants and flavorings with or without nicotine, is heated and turned into vapor through the atomizer. The vapor released through the mouth during suction creates a sensation similar to smoking. The composition of the e-liquid and its nicotine level is different according to the available commercial brands (12).
In recent years, the use of e-cigarettes has increased significantly so that in the United States, 1 out of every 5 smokers uses an e-cigarette. The experience of using e-cigarettes among young people has increased from 3.2% in 2011 to 6.8% in 2012 (11) due to its availability (13), the existence of different flavors in the e-liquid (14), and being considered modern (11,12). In addition, the increasing use of e-cigarettes is due to the view that e-cigarettes can be used as a safe tool to quit smoking by replacing conventional cigarettes. The public's belief that its use creates low risk or is safe for people's health has also fueled this issue (15).
According to some sources, since combustion does not occur in e-cigarettes, many harmful substances caused by the combustion of tobacco in conventional cigarettes are not produced in this device (16). However, the results of studies on people using e-cigarettes show a series of complications. In these people, the urinary level of dangerous metabolites for health (e.g., propylene oxide, acrolein, acrylonitrile, and crotonaldehyde) is twice that of non-smokers (17). In the lungs, small particles can be seen which are formed from propylene glycol. Moreover, the presence of nicotine in the e-liquid increases the level of exhaled nitric oxide and stimulates the inflammation of the respiratory tract (18). The use of e-cigarettes in non-smokers has short-term effects on the function of platelets and increases their aggregation, causing damage to vascular tissue and changing the vascular tonicity (18).
On the other hand, studies also indicate that the use of e-cigarettes not only does not play any important role in quitting smoking but also increases people's desire to smoke. Especially, in cases where the e-liquid contains nicotine, due to its highly addictive effects, many e-cigarette users turn to conventional cigarette smoking. Therefore, the e-cigarette, which was originally created as a smoking cessation tool, is the gateway to conventional cigarette smoking (11,19).

Discussion
Based on the aim of this study, which was conducted to investigate e-cigarette as a cessation tool or a new way to get into conventional smoking, Glantz's study indicated no significant relationship between e-cigarette use and smoking cessation (20). Further, WHO declares that e-cigarette cannot be considered as an efficient and effective way to quit smoking by stressing the necessity of conducting more detailed studies and providing more convincing pieces of evidence. In addition to the type of e-liquid composition inside the cartridge, the type of materials used in the construction of the body and different parts of the device were also considered as effective factors in creating the risks of consuming this type of cigarette (12).
The results of a longitudinal study in England declared that there is a relationship between the experience of using e-cigarettes and the subsequent experience of conventional smoking. The fear that the use of e-cigarettes through the gateway effect will increase smoking among young people has led countries to pass laws on how to use e-cigarettes or prohibit their use (21). King et al even demonstrated that passive exposure to e-cigarettes is effective in increasing the desire to use e-cigarettes followed by conventional cigarettes (11).

Conclusion
According to the mentioned complications, e-cigarette cannot be introduced as a safe alternative for smoking cessation, and more scientific evidence is needed. In addition, due to the potentiality of e-cigarette to create a gateway for people to enter conventional smoking and greater attraction of young adults to smoking this type of cigarette, countries should enact laws regarding distribution, access, and prohibitions.