The Dangers of Vaping

Abstract

As our nation turns away from smoking tobacco and toward legalization of marijuana, vaporization of both plants has increased in popularity. There are medical and cultural implications of this new trend which are just recently being reported and investigated. The purpose of this article is to review the scientific and sociological literature as it pertains to the vaporization of both marijuana and tobacco products and the potential medical and cultural implications of this new phenomenon.

Background

The invention of vaping is attributed to Herbert Gilbert, a cigarette smoker and scrap metal dealer from Pennsylvania. Gilbert’s device was battery-powered to vaporize a liquid for inhalation, very similar to modern electronic cigarettes. He admitted to the Smithsonian magazine that he believed it to be a breakthrough alternative to cigarette smoking to save people from tobacco’s harmful effects as it did not contain nicotine. After multiple permutations, the device was never mass-produced but its patent has been cited by many companies since then. He actually proposed an alternative use for the device for people that were dieting and believed that they could vaporize the tastes of their favorite foods to quench food cravings. He initially proposed a handful of flavorings including cinnamon, rum, orange, and mint.^1–2 A year after the patent was submitted in 1963, the Surgeon General Luther Terry released his report “Smoking and Health” on the potential health consequences of cigarette smoking. This was the first report implicating cigarettes in a causal relationship with lung cancer and heart disease as well as laryngeal cancer and chronic bronchitis.³

Since that time, “vaping” as it is called has diverged into two very separate activities with some common elements. The practice of vaporizing tobacco products and nicotine-containing liquids continued to be developed and has manifested in the modern day in the form of both commercial and custom-made dedicated devices. Separately, in the early 1990s vaping emerged as a new method to use marijuana both recreationally and medicinally.⁴ These behaviors have significant overlap in the devices used for inhalation, the cultural changes associated with their acceptance, and the potential health effects. In this article, we will examine the cultural and medical implications of vaping as well as some obstacles to good scientific study.

Cultural

Al though vaping tobacco was initially conceived as a healthier way to smoke, it took on a life and an industry of its own. In 2019, vaping tobacco is a new gateway to nicotine abuse that frequently skips the initial phase of addiction to cigarettes. It has been perceived as safer, better tasting, more efficient, and more discrete. Vaping tobacco provides new users with an overall better initial experience when compared to the first time smoking cigarettes.^4–5 Eighty years ago, cigarette smoking was culturally accepted and even considered “cool.” In the present day, vaping tobacco has its own culture that is often separate from cigarette smoking. Substantial marketing investment by tobacco companies in response to a decrease in combustible cigarette consumption in the last few years has led to an overall normalization of vaping tobacco and a change in perception that it is safe. Combustible cigarette smoking has become culturally stigmatized, with many cities outlawing tobacco smoking in bars and restaurants and sometimes even on the street. Vaping is a method by which people can consume tobacco products without being part of a fringe and marginalized group.^4–6

Marijuana has always had its own culture. Induction into this culture previously required a supplier of the illegal drug that would also provide education about how to smoke it, either through pipes or rolled into cigarette form. There are many generations of marijuana smokers who are now considering the long-term health effects of smoking. Much like with vaping tobacco products, chronic marijuana smokers are vaporizing marijuana as a potentially healthier alternative. This is especially true of the “Baby Boomer” generation.⁷ The legalization of marijuana has drastically changed the landscape of the use of this drug, both in terms of the potency of available products and the methods by which it can be ingested or inhaled. In states where marijuana has become legal, vaporizing marijuana oils is more convenient and more popular.^6,7

A final cultural consideration of vaporization of tobacco is the misunderstanding that vaporizing tobacco is somehow a viable way to quit smoking cigarettes. No clinical trials have been able to show that vaping helps reduce cigarette smoking, but there are some trials that show that dual-use is common and that many people who start vaping with the intention to quit smoking end up smoking cigarettes and vaping tobacco. They are acquiring the risk profiles of both activities without benefit.⁸ It is common to see patients in this group feel somehow encouraged that through vaping they have been able to reduce their intake of combustible cigarettes, with no consideration to the unknown possible dangers of vaporizing.⁹

Problems with Studies

Good clinical evidence is lacking regarding the potential harm of vaping or the potential benefits. There are some problems with studying something like vaping. For one thing, any research has to make a distinction between vaporizing marijuana and vaporizing tobacco and this is not always possible. Additionally, the methods by which people vaporize tobacco and marijuana differ. As far as tobacco devices go, there are many brands with many different compositions and construction designs. Regarding the vaporization of marijuana, there are no standardized devices and there are no standard formulations.

Studies to prove a benefit of vaporizing tobacco over smoking cigarettes have been confounded by the lack of a direct correlation between the number of puffs of an electronic cigarette and the number of conventional cigarettes smoked. With different brands of electronic cigarettes having different chemical ingredients and different concentrations of nicotine, the issue is even more complicated.^9,10 Many of the studies performed on electronic cigarettes used a Nicorette inhaler as a control for comparison. It is important to note that the Nicorette inhaler does not heat its component chemical liquid, where vaporization does heat the internal components and the liquids.¹¹

The studies on the safety or dangers of vaporizing marijuana are limited in number because the marijuana itself is difficult to acquire. There were a small number of the plants released in the early 90s for clinical research.¹² Most of those studies utilized the same device, manufactured under the name “Volcano”. This device is expensive and is drastically different from any of the modern handheld devices for vaporizing marijuana and tobacco. It does not serve as a good facsimile for comparison to modern day vaporization technology. Many of the clinical research studies available focus on aspects of vaping such as the amount of nicotine or marijuana delivered but there’s not a great deal of evidence on the analysis of other toxins released both from vaporizing tobacco leaf products and marijuana. With all of these limitations, most of the available studies are non-clinical or have very small numbers of study subjects. A strong and thorough assessment of the potential dangers of vaporizing tobacco and marijuana products has not been forthcoming.^12,13

Medical Dangers of Vaping

All of the medical dangers of vaping are unknown. Only a small number of people who admit to vaping marijuana are doing so for medical reasons, and there are almost no studies. A large number of people believe that vaping tobacco is a healthy way to quit, and this belief has been fostered by the tobacco industry.^6,14 There is no strong clinical signal in the direction of using electronic cigarettes as an effective method of quitting smoking. It is difficult to hold an informed discussion with patients about the potential risks and benefits of vaping. Potential risks come from multiple places: device specific concerns, the makeup of the liquid products being vaporized, and the potential for toxicity of both nicotine and marijuana when inhaled in concentrated forms.

Chemical Composition of the Liquid Products

The pharmacologically active components of vaping products are not regulated, and the methods by which they are extracted and suspended in solution vary greatly. The user believes they are inhaling a pure form of THC (the active component of marijuana) or nicotine but there is often little regard for what else is being inhaled concomitantly. The risk profiles of these inhaled chemical mixtures change significantly depending upon the method by which they are vaporized or heated.^15–17

The conventional solvents for the dissolution of nicotine or THC have been propylene glycol and glycerol, and these are the best studied. Initially thought to be benign, there is now some research demonstrating that propylene glycol when vaporized causes significant respiratory irritation and even increases the incidence of asthma. The breakdown products from heating propylene glycol and glycerol to target temperatures include formaldehyde and hemiacetals such as acetaldehyde. Formaldehyde is a Group 1 carcinogen that contributes a 5–15 times higher lifetime risk of cancer. It is present in traditional smoked tobacco in much lower quantities. Hemiacetals such as acrolein and acetone have been implicated in nasal irritation, cardiovascular effects, and lung mucosal damage and these byproducts are produced in higher quantities with higher voltage devices. Basically, as the temperature of the coil increases, the carcinogenic risk of vaping approaches that of traditionally smoked cigarettes.^9,10,16–18

The flavorings added to the nicotine and THC extracts represent a separate but no less worrisome health risk. We tend to think of food additives as safe, and we sometimes learn empirically about the hazards they pose when people are exposed to them in ways other than direct ingestion. Diacetyl is a food additive that is also used in flavoring electronic cigarettes that approximates the flavor of butter. In the early 2000s, diacetyl was implicated as a cause of bronchiolitis obliterans organizing pneumonia (BOOP) in factory workers exposed to it in large quantities. Although it is considered safe to eat, exposure to this chemical is regulated and limited by OSHA due to its proven health effects.^8,19 The flavoring additives of electronic cigarettes on the mass market are typically passed through the FDA under a provision that these chemicals, almost exclusively synthetic, are “generally accepted as safe” for human consumption. The caveat with this provision is that consumption refers to oral ingestion. It is unknown what potential health effects result when something perfectly safe to eat and digest is vaporized at 500 degrees and inhaled. Some research is demonstrating that the flavorings incorporated into electronic cigarettes have cytotoxic effects.⁸ Furthermore, sweeter flavorings tend to contain stronger oxidizers. One study used a murine model of lung epithelial cells and demonstrated a higher release of inflammatory cytokines IL-6 and IL-8 as well as fibroblastic changes in the subjects exposed to sweeter electronic cigarette flavorings, with the mice appearing to lose redox balance.²⁰

Problems with Manufacturing of E-Cigarettes

There is no real regulation of either nicotine-containing electronic cigarette products or marijuana extracts for vaping. Every part of the manufacturing process allows for error and contamination, with too many unknowns about the potential dangers of vaporizing each individual component. With marijuana still being illegal in many states and on the federal level, this is even more of a problem with THC containing products available on the black market. Recent research has shown that Vitamin E is a new solvent into which these THC extracts are dissolved, probably due to its relative ease of acquisition. All of the health effects of inhaling vaporized vitamin E are unknown.²¹ There is recent evidence that vaporized vitamin E oil may be a cause of Electronic cigarette and Vaping Associated Lung Injury (EVALI). The simplest and highest-yield method of extracting THC oil from marijuana buds utilizes a rudimentary setup that exploits certain properties of compressed butane gas, called “supercritical fluid extraction”. The traditional backyard equipment setup is a PVC pipe and a butane lighter refill canister which, under the right conditions, can explode with multiple case reports of severe burns. Most of those who self-report home extraction of THC oil learned how to do so from materials available on the internet, and by watching videos on Youtube.^22,23

Toxicity of Nicotine and THC

It bears noting that when vaping is successful and delivers concentrated nicotine or THC to the user, the amount of drug delivered is much higher than would typically be inhaled by burning and smoking the raw tobacco or marijuana plant. Sociological questionnaires on vaping habits reveal a trend toward dabbing THC contributing to addictive behavior not reported by those users who smoke marijuana in a non-concentrated form. The same pattern of addiction, tolerance, and withdrawal that has been observed in drugs like heroin, traditionally considered “hard drugs”, is now being reported in those vaping THC.^5,6,15,24 There have been some cases of nicotine poisoning from using electronic cigarettes, with an increased risk of toxicity associated with customized devices and higher nicotine concentrations in the liquids. Finally, many of those who attempted to quit cigarettes by transitioning to vaping are reporting that quitting vaping is actually significantly harder than quitting smoking traditional cigarettes, with some respondents even turning back to cigarettes as a way to help wean off their vaporizer device.^25–27

Device-Specific Concerns

The basic design of the device, in the case of vaping both tobacco and marijuana, is largely unchanged from the original patent by Gilbert. There is a reservoir that holds an oil or liquid, a mouthpiece, and a heating element. Theoretically, vaporizing the liquid does not combust it and saves the person vaping from exposure to byproducts generated by high heat. However, there is no regulation of these devices and no agreed upon standard temperature. There appears to be a wide variance in the quality of the components of these devices depending on the price of purchase.^{2,10,11,16,28}

There are multiple different metals used for the heating element, including: Nichrome (nickel-chrome), tungsten, stainless steel, and Kanthal (Ferritic iron chromium aluminum alloy) among others. Powered by a battery, the element wire is heated to a temperature range around 375–525 degrees. The long term effects of sustained exposure to the oxide products of these metals are unknown.^2,16,28

There are manufactured electronic cigarettes under various brand names (Figure 1), but there is also a subculture of people who vape either tobacco and marijuana (or both) through devices that they custom build, referred to as “mods”. There are many websites and physical stores catering to this hobby, and there are many different accessories and components available to change different aspects of device performance. A user can find stronger batteries, a wide array of device designs, and an even broader selection of metals for the heating element in different lengths and diameters. The practice of “direct dripping” involves users directly dripping the vaping liquid onto a heated coil with the express intention of increasing the quantity of vapor as well as increasing the concentration of the active ingredients being vaped.^6,16,20,29 This practice increases toxin exposure and often goes along with modified devices that increase temperature by increasing voltage. Increasing the voltage of the device with stronger batteries and driving higher temperatures on the heating coils has been shown to approach equivalency with cigarettes in terms of exposure to carcinogens. It is unknown what other potential health effects are caused by modifying these properties of the device.¹⁰

Figure 1.

Vaping Brands Chart- E-cigarette Product Use, or Vaping, Among Persons with Associated Lung Injury — Illinois and Wisconsin, April–September 2019.

Ghinai I, Pray IW, Navon L, et al. MMWR Morb Mortal Wkly Rep 2019;68:865–869.

Shifting Perspectives on Vaping

The smoking of tobacco in pipes and cigarettes used to be much more common, and it took a long time to realize the true dangers of combustible cigarette smoking. The terminology used can be confusing (Figure 2). The available body of medical literature regarding the potential harms of vaping consists of data from animal models, observational studies with small numbers of subjects, and single case reports and series. One observational study utilized pulmonary function tests to show that vaping decreases FeNO and increases respiratory impedance.³⁰ There have been multiple case reports of vaping-associated lipoid pneumonia. As previously mentioned, there have been reports of both THC and nicotine toxicity. There are many reports of mechanical injury and burns from malfunctioning devices. The perception that vaping is safe is starting to change.

Figure 2.

Vaping Terminology

An additional common theme has been that many of the electronic cigarette and vaping associate lung injury (EVALI) cases are related to black-market THC products marketed under a variety of brand names. In one study, approximately 96% of THC for vaping was typically sold in pre-filled cartridges or “carts”. A clear majority, over 60%, were sold under the label ‘Dank Vapes.’ This does not represent an actual brand, but rather a type of empty packaging readily available online and in vaping shops which can then be filled with whatever homemade product a dealer has at their disposal. It is not widely known by consumers that Dank Vapes is not a brand, and this may contribute to a sense of false trust.^31,32

Conclusion

The cultural phenomenon of vaping both marijuana and nicotine were billed as a healthy alternative to smoking and at times even seen as an option to aid in cessation. With the current body of evidence and the outbreak of EVALI in 2019, it is incumbent upon all healthcare practitioners to advise patients that vaping should not be considered safer than smoking and that there are very real and new dangers associated with vaping that still require further study. Providers must learn more about the dangers of vaping and identify adverse health effects from this practice in patients. An evidence-based approach to smoking cessation based on established data and practice patterns is needed.