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The prevalence and popularity of electronic cigarettes or “vaping” have grown dramatically over the last several years in the United States. Although new studies targeting these products are being done at increasing frequency, there remains a relative paucity of data regarding the long-term risks. Proponents argue that they can be used as a cessation tool for smokers, or failing that, a safer replacement for traditional cigarettes. Opponents make the case that the perception of safety could contribute to increased use in people who may have otherwise never smoked, leading to an overall increase in nicotine use and addiction. This is most readily seen in the adolescent population, where use has skyrocketed, leading to concerns about how electronic cigarettes are marketed to youth, as well as the ease of access.
Basics of vaping (devices)
In its most basic form, an electronic cigarette consists of a battery that powers a heating coil. This heating coil applies heat to a wick, which is soaked in liquid, “vape juice,” converting it into a vapor that is then directly inhaled. However, there can be many variations on this simple theme. Early generation products resembled traditional cigarettes in size and shape and were marketed as smoking cessation aids. Newer devices have abandoned this look and strategy. Preloaded cartridges have been replaced by large tanks that the user can fill with the liquid of their choosing. Multiple tanks can be purchased for a single device, enabling the user to have multiple flavors or various levels of nicotine dosing on hand for quick changing, depending on user preference or mood. Additionally, there are variable voltage settings, resulting in different styles of vapor and/or “throat hit” (the description of the desired burning vs smooth effect of the vapor on the oropharynx). This type of device invites experimentation. Multiple flavors can be used in isolation or mixed together at various temperatures. It no longer resembles classic cigarettes, and the flavor and experience are more prominently promoted. One can see that this device has more appeal to a “never smoker” than the original products, and there is concern that it is being marketed as such with some success (Dinakar C, et al. N Engl J Med. 2016;375[14]:1372).
E-liquid
Perhaps more important than the devices themselves is an understanding of the components of the liquid used to generate the inhaled aerosol.
Typically, four components are present:
• Propylene glycol
• Vegetable glycerin
• Flavoring
• Nicotine
The first two components are generally considered nontoxic, based on their use as food additives. However, inhalation is a novel route of entry and the long-term effects on the respiratory tract are unclear.
The third component, “flavorings,” is a catch-all term for the hundreds of different flavors and styles of e-liquids available today, ranging from menthol to fruit or candy and everything in between. It is difficult to account for all the potential effects of the numerous flavorings being used, especially when some are combined by the end user to various degrees.
Nicotine is present, specified in varying doses. However, vaping style, experience, and type of device used can dramatically affect how much is absorbed, making dosages difficult to predict. Additionally, labeled doses are prone to wide ranges of error (Schraufnagel DE, et al. Am J Respir Crit Care Med. 2014;190[6]:611).
What are the risks?
Cancer
A handful of known carcinogens can be found in inhaled vapor, including formaldehyde, acetaldehyde, acrolein, toluene, and nitrosamines. However, they are present in far lower concentrations than in traditional cigarettes (Goniewicz ML, et al. JAMA Netw Open. 2018;1[8]e185937). This leads to the natural assumption that vaping, while not benign, poses a much lower cancer risk when compared with smoking. Whether that is borne out in the long term remains to be seen.
Pulmonary function
The long-term effect on pulmonary function is not known. Small studies have shown no significant changes to spirometry after acute exposure to vapor. More data are needed in this area (Palazzolo DL. Frontiers Public Health. 2013;1[56]1-20).
Wound healing
An animal study has shown evidence of poor wound healing extrapolated from skin flap necrosis in rats. Exposure to vapor vs smoke yielded similar results, and both were worse than the sham arm (Troiano C, et al. JAMA Facial Plast Surg. 2019;21[1]:5). While it is difficult to know how to apply this clinically, it may be prudent to advise patients to abstain while in preparation for elective surgery.
Cardiovascular/stroke
Much of the cardiovascular toxicity from cigarette use is tied to the myriad of complex toxic particles produced in inhaled smoke, the vast majority of which are not present in e-cigarette vapor. While nicotine itself has known acute cardiovascular effects, including tachycardia and vasoconstriction, a tolerance to these effects occurs over time. Previous evaluations of nicotine replacement therapies and smokeless tobacco for their cardiovascular effects have had mixed results. But, there appears to be a trend toward minimal cardiovascular risk when using “cleaner” products, such as nicotine replacement therapy compared with smokeless tobacco (Benowitz NL, et al. Nature Rev Cardiol. 2017;14[8]:447). Whether this can be extrapolated to electronic cigarette use is unknown but is encouraging.
Alternative toxicity
In addition to the above risks that are in comparison to traditional smoking, vaping also introduces novel toxicities. There are case reports of lipoid pneumonia, ARDS, hypersensitivity pneumonitis, eosinophilic pneumonia, and diffuse alveola hemorrhage. Burns from malfunctioning devices must also be considered, as there is a wide array of products available, at differing levels of build quality.
Toxic oral ingestion of nicotine, especially by children, has led to increased calls to poison centers. For a small child, this can be fatal. Regulation of labels and containers could curtail this issue. But, public education regarding the toxicity of these substances when ingested in large quantities is also important. If there is a lack of understanding about this danger, then typical safeguards are easily overlooked by individual users.
Are there benefits?
Smoking cessation
Compared with other products, such as nicotine patches, gum, and pharmaceutical methods, e-cigarettes most closely mimic the actual experience of smoking. For some, the habit and ritual of smoking is as much a part of the addiction as nicotine. Vaping has the potential to help alleviate this difficult aspect of cessation. Data involving early generation products failed to show a significant advantage. Newer devices that are more pleasurable to use and offer more efficient nicotine delivery may be more effective. Indeed, a recent study in the New England Journal of Medicine from this year demonstrated improved smoking cessation compared with traditional methods, using second generation vape devices (Hajek P, et al. N Engl J Med. 2019;380[7]629). It will be interesting to see if this can be repeatable going forward and if protocols can be established to maximize effectiveness.
As outlined above, it is difficult to make definitive conclusions or recommendations regarding electronic cigarette use at the present time. The risk of cancer and cardiopulmonary disease is likely to be significantly lower but not eliminated. Use as a smoking cessation aid is starting to show promise. Even without cessation, ongoing vaping is likely to be safer than ongoing smoking. Two caveats to this remain: some patients, in an effort to quit smoking, may take up vaping but eventually become “dual users.” This scenario has been associated with higher toxic exposure and possibly worse outcomes. The second caveat is that while there is promise to using this as a cessation tool, it should not yet replace other more well-studied, first-line agents in this regard. It should, perhaps, target patients who are motivated to quit but have failed more traditional methods. Finally, there continues to be concern that vaping could appeal to never smokers, given its perceived safety profile and ease of use in public places. This could lead to an overall increase in nicotine addiction, which could be a significant step backwards.
Dr. Clark is Assistant Professor, Pulmonary and Critical Care Medicine, UT Southwestern Medical Center, Dallas, Texas.
The prevalence and popularity of electronic cigarettes or “vaping” have grown dramatically over the last several years in the United States. Although new studies targeting these products are being done at increasing frequency, there remains a relative paucity of data regarding the long-term risks. Proponents argue that they can be used as a cessation tool for smokers, or failing that, a safer replacement for traditional cigarettes. Opponents make the case that the perception of safety could contribute to increased use in people who may have otherwise never smoked, leading to an overall increase in nicotine use and addiction. This is most readily seen in the adolescent population, where use has skyrocketed, leading to concerns about how electronic cigarettes are marketed to youth, as well as the ease of access.
Basics of vaping (devices)
In its most basic form, an electronic cigarette consists of a battery that powers a heating coil. This heating coil applies heat to a wick, which is soaked in liquid, “vape juice,” converting it into a vapor that is then directly inhaled. However, there can be many variations on this simple theme. Early generation products resembled traditional cigarettes in size and shape and were marketed as smoking cessation aids. Newer devices have abandoned this look and strategy. Preloaded cartridges have been replaced by large tanks that the user can fill with the liquid of their choosing. Multiple tanks can be purchased for a single device, enabling the user to have multiple flavors or various levels of nicotine dosing on hand for quick changing, depending on user preference or mood. Additionally, there are variable voltage settings, resulting in different styles of vapor and/or “throat hit” (the description of the desired burning vs smooth effect of the vapor on the oropharynx). This type of device invites experimentation. Multiple flavors can be used in isolation or mixed together at various temperatures. It no longer resembles classic cigarettes, and the flavor and experience are more prominently promoted. One can see that this device has more appeal to a “never smoker” than the original products, and there is concern that it is being marketed as such with some success (Dinakar C, et al. N Engl J Med. 2016;375[14]:1372).
E-liquid
Perhaps more important than the devices themselves is an understanding of the components of the liquid used to generate the inhaled aerosol.
Typically, four components are present:
• Propylene glycol
• Vegetable glycerin
• Flavoring
• Nicotine
The first two components are generally considered nontoxic, based on their use as food additives. However, inhalation is a novel route of entry and the long-term effects on the respiratory tract are unclear.
The third component, “flavorings,” is a catch-all term for the hundreds of different flavors and styles of e-liquids available today, ranging from menthol to fruit or candy and everything in between. It is difficult to account for all the potential effects of the numerous flavorings being used, especially when some are combined by the end user to various degrees.
Nicotine is present, specified in varying doses. However, vaping style, experience, and type of device used can dramatically affect how much is absorbed, making dosages difficult to predict. Additionally, labeled doses are prone to wide ranges of error (Schraufnagel DE, et al. Am J Respir Crit Care Med. 2014;190[6]:611).
What are the risks?
Cancer
A handful of known carcinogens can be found in inhaled vapor, including formaldehyde, acetaldehyde, acrolein, toluene, and nitrosamines. However, they are present in far lower concentrations than in traditional cigarettes (Goniewicz ML, et al. JAMA Netw Open. 2018;1[8]e185937). This leads to the natural assumption that vaping, while not benign, poses a much lower cancer risk when compared with smoking. Whether that is borne out in the long term remains to be seen.
Pulmonary function
The long-term effect on pulmonary function is not known. Small studies have shown no significant changes to spirometry after acute exposure to vapor. More data are needed in this area (Palazzolo DL. Frontiers Public Health. 2013;1[56]1-20).
Wound healing
An animal study has shown evidence of poor wound healing extrapolated from skin flap necrosis in rats. Exposure to vapor vs smoke yielded similar results, and both were worse than the sham arm (Troiano C, et al. JAMA Facial Plast Surg. 2019;21[1]:5). While it is difficult to know how to apply this clinically, it may be prudent to advise patients to abstain while in preparation for elective surgery.
Cardiovascular/stroke
Much of the cardiovascular toxicity from cigarette use is tied to the myriad of complex toxic particles produced in inhaled smoke, the vast majority of which are not present in e-cigarette vapor. While nicotine itself has known acute cardiovascular effects, including tachycardia and vasoconstriction, a tolerance to these effects occurs over time. Previous evaluations of nicotine replacement therapies and smokeless tobacco for their cardiovascular effects have had mixed results. But, there appears to be a trend toward minimal cardiovascular risk when using “cleaner” products, such as nicotine replacement therapy compared with smokeless tobacco (Benowitz NL, et al. Nature Rev Cardiol. 2017;14[8]:447). Whether this can be extrapolated to electronic cigarette use is unknown but is encouraging.
Alternative toxicity
In addition to the above risks that are in comparison to traditional smoking, vaping also introduces novel toxicities. There are case reports of lipoid pneumonia, ARDS, hypersensitivity pneumonitis, eosinophilic pneumonia, and diffuse alveola hemorrhage. Burns from malfunctioning devices must also be considered, as there is a wide array of products available, at differing levels of build quality.
Toxic oral ingestion of nicotine, especially by children, has led to increased calls to poison centers. For a small child, this can be fatal. Regulation of labels and containers could curtail this issue. But, public education regarding the toxicity of these substances when ingested in large quantities is also important. If there is a lack of understanding about this danger, then typical safeguards are easily overlooked by individual users.
Are there benefits?
Smoking cessation
Compared with other products, such as nicotine patches, gum, and pharmaceutical methods, e-cigarettes most closely mimic the actual experience of smoking. For some, the habit and ritual of smoking is as much a part of the addiction as nicotine. Vaping has the potential to help alleviate this difficult aspect of cessation. Data involving early generation products failed to show a significant advantage. Newer devices that are more pleasurable to use and offer more efficient nicotine delivery may be more effective. Indeed, a recent study in the New England Journal of Medicine from this year demonstrated improved smoking cessation compared with traditional methods, using second generation vape devices (Hajek P, et al. N Engl J Med. 2019;380[7]629). It will be interesting to see if this can be repeatable going forward and if protocols can be established to maximize effectiveness.
As outlined above, it is difficult to make definitive conclusions or recommendations regarding electronic cigarette use at the present time. The risk of cancer and cardiopulmonary disease is likely to be significantly lower but not eliminated. Use as a smoking cessation aid is starting to show promise. Even without cessation, ongoing vaping is likely to be safer than ongoing smoking. Two caveats to this remain: some patients, in an effort to quit smoking, may take up vaping but eventually become “dual users.” This scenario has been associated with higher toxic exposure and possibly worse outcomes. The second caveat is that while there is promise to using this as a cessation tool, it should not yet replace other more well-studied, first-line agents in this regard. It should, perhaps, target patients who are motivated to quit but have failed more traditional methods. Finally, there continues to be concern that vaping could appeal to never smokers, given its perceived safety profile and ease of use in public places. This could lead to an overall increase in nicotine addiction, which could be a significant step backwards.
Dr. Clark is Assistant Professor, Pulmonary and Critical Care Medicine, UT Southwestern Medical Center, Dallas, Texas.
The prevalence and popularity of electronic cigarettes or “vaping” have grown dramatically over the last several years in the United States. Although new studies targeting these products are being done at increasing frequency, there remains a relative paucity of data regarding the long-term risks. Proponents argue that they can be used as a cessation tool for smokers, or failing that, a safer replacement for traditional cigarettes. Opponents make the case that the perception of safety could contribute to increased use in people who may have otherwise never smoked, leading to an overall increase in nicotine use and addiction. This is most readily seen in the adolescent population, where use has skyrocketed, leading to concerns about how electronic cigarettes are marketed to youth, as well as the ease of access.
Basics of vaping (devices)
In its most basic form, an electronic cigarette consists of a battery that powers a heating coil. This heating coil applies heat to a wick, which is soaked in liquid, “vape juice,” converting it into a vapor that is then directly inhaled. However, there can be many variations on this simple theme. Early generation products resembled traditional cigarettes in size and shape and were marketed as smoking cessation aids. Newer devices have abandoned this look and strategy. Preloaded cartridges have been replaced by large tanks that the user can fill with the liquid of their choosing. Multiple tanks can be purchased for a single device, enabling the user to have multiple flavors or various levels of nicotine dosing on hand for quick changing, depending on user preference or mood. Additionally, there are variable voltage settings, resulting in different styles of vapor and/or “throat hit” (the description of the desired burning vs smooth effect of the vapor on the oropharynx). This type of device invites experimentation. Multiple flavors can be used in isolation or mixed together at various temperatures. It no longer resembles classic cigarettes, and the flavor and experience are more prominently promoted. One can see that this device has more appeal to a “never smoker” than the original products, and there is concern that it is being marketed as such with some success (Dinakar C, et al. N Engl J Med. 2016;375[14]:1372).
E-liquid
Perhaps more important than the devices themselves is an understanding of the components of the liquid used to generate the inhaled aerosol.
Typically, four components are present:
• Propylene glycol
• Vegetable glycerin
• Flavoring
• Nicotine
The first two components are generally considered nontoxic, based on their use as food additives. However, inhalation is a novel route of entry and the long-term effects on the respiratory tract are unclear.
The third component, “flavorings,” is a catch-all term for the hundreds of different flavors and styles of e-liquids available today, ranging from menthol to fruit or candy and everything in between. It is difficult to account for all the potential effects of the numerous flavorings being used, especially when some are combined by the end user to various degrees.
Nicotine is present, specified in varying doses. However, vaping style, experience, and type of device used can dramatically affect how much is absorbed, making dosages difficult to predict. Additionally, labeled doses are prone to wide ranges of error (Schraufnagel DE, et al. Am J Respir Crit Care Med. 2014;190[6]:611).
What are the risks?
Cancer
A handful of known carcinogens can be found in inhaled vapor, including formaldehyde, acetaldehyde, acrolein, toluene, and nitrosamines. However, they are present in far lower concentrations than in traditional cigarettes (Goniewicz ML, et al. JAMA Netw Open. 2018;1[8]e185937). This leads to the natural assumption that vaping, while not benign, poses a much lower cancer risk when compared with smoking. Whether that is borne out in the long term remains to be seen.
Pulmonary function
The long-term effect on pulmonary function is not known. Small studies have shown no significant changes to spirometry after acute exposure to vapor. More data are needed in this area (Palazzolo DL. Frontiers Public Health. 2013;1[56]1-20).
Wound healing
An animal study has shown evidence of poor wound healing extrapolated from skin flap necrosis in rats. Exposure to vapor vs smoke yielded similar results, and both were worse than the sham arm (Troiano C, et al. JAMA Facial Plast Surg. 2019;21[1]:5). While it is difficult to know how to apply this clinically, it may be prudent to advise patients to abstain while in preparation for elective surgery.
Cardiovascular/stroke
Much of the cardiovascular toxicity from cigarette use is tied to the myriad of complex toxic particles produced in inhaled smoke, the vast majority of which are not present in e-cigarette vapor. While nicotine itself has known acute cardiovascular effects, including tachycardia and vasoconstriction, a tolerance to these effects occurs over time. Previous evaluations of nicotine replacement therapies and smokeless tobacco for their cardiovascular effects have had mixed results. But, there appears to be a trend toward minimal cardiovascular risk when using “cleaner” products, such as nicotine replacement therapy compared with smokeless tobacco (Benowitz NL, et al. Nature Rev Cardiol. 2017;14[8]:447). Whether this can be extrapolated to electronic cigarette use is unknown but is encouraging.
Alternative toxicity
In addition to the above risks that are in comparison to traditional smoking, vaping also introduces novel toxicities. There are case reports of lipoid pneumonia, ARDS, hypersensitivity pneumonitis, eosinophilic pneumonia, and diffuse alveola hemorrhage. Burns from malfunctioning devices must also be considered, as there is a wide array of products available, at differing levels of build quality.
Toxic oral ingestion of nicotine, especially by children, has led to increased calls to poison centers. For a small child, this can be fatal. Regulation of labels and containers could curtail this issue. But, public education regarding the toxicity of these substances when ingested in large quantities is also important. If there is a lack of understanding about this danger, then typical safeguards are easily overlooked by individual users.
Are there benefits?
Smoking cessation
Compared with other products, such as nicotine patches, gum, and pharmaceutical methods, e-cigarettes most closely mimic the actual experience of smoking. For some, the habit and ritual of smoking is as much a part of the addiction as nicotine. Vaping has the potential to help alleviate this difficult aspect of cessation. Data involving early generation products failed to show a significant advantage. Newer devices that are more pleasurable to use and offer more efficient nicotine delivery may be more effective. Indeed, a recent study in the New England Journal of Medicine from this year demonstrated improved smoking cessation compared with traditional methods, using second generation vape devices (Hajek P, et al. N Engl J Med. 2019;380[7]629). It will be interesting to see if this can be repeatable going forward and if protocols can be established to maximize effectiveness.
As outlined above, it is difficult to make definitive conclusions or recommendations regarding electronic cigarette use at the present time. The risk of cancer and cardiopulmonary disease is likely to be significantly lower but not eliminated. Use as a smoking cessation aid is starting to show promise. Even without cessation, ongoing vaping is likely to be safer than ongoing smoking. Two caveats to this remain: some patients, in an effort to quit smoking, may take up vaping but eventually become “dual users.” This scenario has been associated with higher toxic exposure and possibly worse outcomes. The second caveat is that while there is promise to using this as a cessation tool, it should not yet replace other more well-studied, first-line agents in this regard. It should, perhaps, target patients who are motivated to quit but have failed more traditional methods. Finally, there continues to be concern that vaping could appeal to never smokers, given its perceived safety profile and ease of use in public places. This could lead to an overall increase in nicotine addiction, which could be a significant step backwards.
Dr. Clark is Assistant Professor, Pulmonary and Critical Care Medicine, UT Southwestern Medical Center, Dallas, Texas.