Impact of E-Cigarettes on Lung Health

As of February 18, 2020, a total of 2,807 hospitalized e-cigarette, or vaping, product use-associated lung injury (EVALI) cases had been reported to the US Centers for Disease Control and Prevention (CDC) from all 50 states, the District of Columbia, Puerto Rico, and US Virgin Islands. The outbreak in EVALI cases began in June 2019 and peaked in September. Although the number of new hospitalized cases and possible cases presenting to the emergency department have been declining since September 2019, EVALI is still a major public health concern.

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Presence of Toxins

The most recent human study examined toxicants found in the fluid obtained following a bronchoalveolar lavage (BAL) in 51 hospitalized patients with EVALI.7 Investigators reported that 48 of the 51 EVALI patients (94%) had vitamin E acetate present in the fluid. Most (94%) had detectable THC or its metabolites in BAL fluid or had reported vaping THC products in the 90 days before the onset of illness. Nicotine or its metabolites were detected in 30 out of 47 case patients (64%), confirming dual vaping of nicotine and THC. The CDC reported that 152 different THC-containing product brands were reported by patients with EVALI.

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Vitamin E

Vitamin E acetate is a cutting agent often used in illicit THC-containing products as a thickener to lower product cost. While vitamin E acetate is generally recognized as safe for ingestion and topically in dermatologic products, it is not safe for inhalation. Once in the lungs, its biotransformation allows vitamin E to penetrate the surfactant layer, reducing the surface tension needed to keep alveolar sacs open and functional during respiration. Also, the byproduct of heating vitamin E acetate is ketene, a reactive compound that acts as a lung irritant.

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Risk of Dependence

A recent study in mice found that daily exposure to nicotine vapor for 6 months activates nicotine dependence pathways. Notably, the study found decreased concentrations of the inhibitory neurotransmitter GABA and excitatory stimulation in central reward areas of the brain. This stimulation may facilitate nicotine-seeking behavior. GABA inhibits the release of dopamine, which normally surges after exposure to nicotine and other drugs, suggesting that GABA has a role in dampening nicotine cravings and smoking behavior. But, if chronic exposure to EC vapor decreases the concentration of available GABA, dopamine increases following exposure to nicotine in the aerosol could go unchecked, promoting dependency.

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Young People Greatly Impacted

Study findings underscore ongoing concerns that younger EC users who report the highest rates of vaping may become addicted to nicotine. Concerns are magnified given that young EC users are also more likely to start smoking traditional cigarettes. Several studies support that EC use is a gateway to conventional cigarette use, with results from a recent meta-analysis reporting that EC use was associated with a three-fold higher risk of subsequent conventional cigarette initiation among ever (vs never) EC users and four-fold higher likelihood for initiating conventional cigarette use within the past month among past 30-day EC users.

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Role of Oral Health Professionals

Dental professionals play an important role in assessing patients for EC use and for educating users about associated harms. For those who are using EC to quit smoking, patients should be instructed to avoid conventional cigarettes and encouraged to use FDA-approved smoking cessation therapies. Patients should be counseled to avoid the use of THC-containing EC or other vaping products, particularly those obtained illegally, and to never add anything to EC or other vaping products. Patients who demonstrate signs of and/or who report symptoms of respiratory disease should be referred for immediate medical evaluation. Additionally, patients dependent on cannabis should be referred to an appropriate healthcare professional and/or substance abuse program for recovery. Clinicians are urged to remain current with new knowledge about adverse health effects of EC so they can effectively advise their patients.

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