e-cig

Electronic nicotine delivery systems (ENDS) are increasingly popular as an alternative to standard ‘combustion’ cigarettes. ENDS come in a large variety of forms and offer adulterant choices that enhance the user’s experience, such as flavors, humectants, and nicotine in different concentrations. There is a common perception that vaping is a safer alternative to traditional tobacco cigarettes as the ‘smoke’ lacks tars and other toxicants found in cigarette smoke⁽¹⁾. That may be true to some extent, however the ability of users to modify ENDS, like adjusting the power wattage, changing the type of heating element, and use of e-liquids with different flavor and nicotine concentrations, will influence the amounts of toxic chemicals in the inhaled aerosol. Under normal circumstances, the vapor contains, contrary to popular opinion, some of the same toxic compounds (formaldehyde, acetaldehyde, acrolein…) that are found in CCs ⁽²⁾. The ability to add custom adulterants to the vape fluid can add to the complexity of assessing potential risks. How modifications, or customizations might contribute to health effects and the generation of harmful chemicals is a topic that deserves more attention.

Devices are usually composed of a heating element, often a disposable metal heating coil, and atomizer tanks which directly produce the vapor. The most common heating coils and atomizer units can be comprised of different metals, such as stainless teel, nickel-chromium or nichrome, Kanthal nickel, or titanium. At usual setting these all work well, however they degrade with extended use. In some devices, users can set temperatures sufficiently high that degradation products of the device hardware such as metals are aerosolized and inhaled along with the vaporized e-liquid containing nicotine, flavoring, and solvents ⁽³⁾. Environmental metal contaminants are known risk factors for cardiovascular disease. Users of eC devices could inadvertently select vaping profiles that promote chemical reactions with the normally low-toxicity e-liquid to generate harmful chemicals in the aerosol they are inhaling at levels even exceeding traditional cigarettes.

Many studies have already brought insight into how device settings can generate levels of metals in inhaled aerosol that are unique to the modifiable aspects of eC devices. One study found increased concentrations of metals such as arsenic (As), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), tin (Sn), and zinc (Zn) concentrations in eC aerosols when the device power is increased from low (20 Watts) to intermediate (40 Watts) settings ⁽⁴⁾. These exposure levels to metals like Ni from ENDS could exceed those of traditional reference cigarettes. It is interesting to note that ENDS from different manufactures emit different concentrations of metals, suggesting that heating and cooling patterns of individual devices could influence the amount of metals released. A similar study also found higher metal levels in aerosol and e-liquid after it comes in contact with the metal heating coil, compared to the original e-liquid in the dispenser vial ⁽⁵⁾. Elevated levels of metal biomarkers such as Cu, Cr, Sn, and Pb were found in the urine of electronic cigarette users. These studies highlight the need to further study how the unique customizable aspects of ENDS technology contribute to the formation of varying levels of contaminants in the inhaled aerosol. There is no question that smoking is a risk factor for cardiovascular disease and can increase blood pressure, heart rate, among other health outcomes. Educating the public about the health burden that ENDS pose and informing users about the potential dangers of vaping at elevated temperatures or using degraded heating components can be a step towards reducing use of new tobacco products.

References:

Benowitz, N. L., & Burbank, A. D. (2016). Cardiovascular toxicity of nicotine: Implications for electronic cigarette use. Trends in cardiovascular medicine, 26(6), 515–523. https://doi.org/10.1016/j.tcm.2016.03.001
Perraud, V., M.J. Lawler, K.T. Malecha, R.M. Johnson, D.A. Herman, N. Staimer et al.: Chemical characterization of nanoparticles and volatiles present in mainstream hookah smoke. Aerosol Science and Technology 53(9): 1023-1039 (2019)
Wylie, B. J., Hauptman, M., Hacker, M. R., & Hawkins, S. S. (2021). Understanding Rising Electronic Cigarette Use. Obstetrics and gynecology, 137(3), 521–527. https://doi.org/10.1097/AOG.0000000000004282
Zhao, D., Navas-Acien, A., Ilievski, V., Slavkovich, V., Olmedo, P., Adria-Mora, B., Domingo-Relloso, A., Aherrera, A., Kleiman, N. J., Rule, A. M., & Hilpert, M. (2019). Metal concentrations in electronic cigarette aerosol: Effect of open-system and closed-system devices and power settings. Environmental research, 174, 125–134. https://doi.org/10.1016/j.envres.2019.04.003
Olmedo, P., Rodrigo, L., Grau-Pérez, M., Hilpert, M., Navas-Acién, A., Téllez-Plaza, M., Pla, A., & Gil, F. (2021). Metal exposure and biomarker levels among e-cigarette users in Spain. Environmental research, 202, 111667. Advance online publication. https://doi.org/10.1016/j.envres.2021.111667
Bhatnagar A, Whitsel LP, Blaha MJ, Huffman MD, Krishan-Sarin S, Maa J, Rigotti N, Robertson RM, Warner JJ; on behalf of the American Heart Association. New and emerging tobacco products and the nicotine endgame: the role of robust regulation and comprehensive tobacco control and prevention: a presidential advisory from the American Heart Association. 2019;139:e937–e958. doi: 10.1161/CIR.0000000000000669.

“The views, opinions and positions expressed within this blog are those of the author(s) alone and do not represent those of the American Heart Association. The accuracy, completeness and validity of any statements made within this article are not guaranteed. We accept no liability for any errors, omissions or representations. The copyright of this content belongs to the author and any liability with regards to infringement of intellectual property rights remains with them. The Early Career Voice blog is not intended to provide medical advice or treatment. Only your healthcare provider can provide that. The American Heart Association recommends that you consult your healthcare provider regarding your personal health matters. If you think you are having a heart attack, stroke or another emergency, please call 911 immediately.”

JUUL Perspective

Adopted from www.juullabs.com/our-story
There was a recent article released on AHA Newsroom discussing a lawsuit to expedite the FDA review of electronic (e)-cigarettes and cigars. The article highlights the premises behind the suit filed by several groups to include medical, public health, and pediatricians due to a lengthy delay by the FDA in reviewing laws surrounding e-cigarettes and cigars. These products such as JUUL, are becoming more popular among younger generations due to the increased number of flavors available (mango, crème brulè, and fruit medley), which has been shown to cause cardiovascular (CV) effects. These electronic products are being marketed as being a cleaner, more stylish product that makes cigarette cessation easier, but there is no evidence to that affect.

I was quite surprised to read this because during the AHA EPI | Lifestyle Specialty Conference there was a topic on the dangers of e-cigarettes and its metabolic toxicity as compared to commercial cigarettes. There is increasing research being conducted on the use of e-cigarettes and the impact they have on the population. The lawsuit filed in the federal court in Maryland, is important because the products will remain on the market indefinitely during the review process with no set deadline for completion. Additionally, advertisements are being targeted toward youth causing an uproar with parents and school officials due to overwhelming incidences of bathroom smoking.

During the Stamler session of the EPI | Lifestyle meeting, Lloyd-Jones discussed the risk of considering these products as safe under the premise of them emitting vapor, when they are producing aerosols (a mixture of particles and water) that can contribute to the onset of chronic diseases. These particulate matters produced are equivalent to the size and concentration of commercial cigarettes with similar incidences of toxin-induced CVD. E-cigarettes have been shown to decrease nitric oxide by 16% after 5 minutes but long term exposure slows the heart rate subsequently preventing vasodilation. Chronic inhalation of e-cigarette or cigar vapor was demonstrated to induce pro-inflammatory and pro-fibrotic proteins such as IL-8, angiopoietin-1 by 31 fold, and EGF by 25 fold. There was additional evidence that kidneys, heart, and liver rendered a significant increase in pro-fibrotic pathway activation and altered CV function and elevated blood pressure. Some of the more alarming data demonstrate, among the common side effects of chronic use of e-cigarettes/cigars are popcorn lung and inflammation that leads to organ damage that cause cardiorenal and hepatic disease.

With e-cigarettes and cigars gaining in popularity, I think there should be more research geared toward understanding the impact they have on the general population. There are ongoing studies exploring second-hand and third-hand smoke on vascular and pulmonary health. FDA has made efforts to reduce the level of nicotine in commercial cigarettes to minimally- or non-addictive levels, but for e-cigarettes and cigars are exempt from those requirements making it potentially unlawful and harmful to public health. Furthermore, they have delayed the deadline for filing applications until August 2021 for commercial cigarettes/cigars and other combustible produces until August 2022. I would venture to say, these studies have indicated adverse inflammatory events that will be multiplied by the time the applications are filed, let alone reviewed. Although companies producing e-cigarettes/cigars are not soliciting to children, the flavors they are manufacturing are enticing to the younger generations. In addition, arguments have been made to the affect that there is no diacetyl contained in these pods. Because they have substituted diacetyl with benzoic acid,, the potential of oxidation of the scavenging agent enhance the opportunity for oxyradicals to be produced within the vascular system subsequently increasing inflammatory responses that lead to vascular injury.

Food for thought, there were issues of these pods exploding due to leaks but the overall health outcome may be worse than the threat of combustion. So, if the cost of e-cigarettes/cigars were to be calculated, does it make sense to spend $10 per pack to increase the potential for a chronic disease by subjecting our youth (and the public) to the aerosols from combustible products? Is it in the best interest of the public for nicotine containing products to be regulated?

Anberitha Matthews, PhD is a Postdoctoral Fellow at the University of Tennessee Health Science Center in Memphis TN. She is living a dream by researching vascular injury as it pertains to oxidative stress, volunteers with the Mississippi State University Alumni Association, serves as Chapter President and does consulting work with regard to scientific editing.

Electronic Cigarette Customization Matters.

E-Cigarettes, Cigars, And Commercial Cigarettes