EVALI: Name of lung lesions linked to vaping
States where cannabis is legal for recreational use have fewer cases of vapor-related lung damage than other states, according to research published earlier this month by the network. JAMA Network Open.
Previous research has found that the culprit for the injuries was likely Vitamin E acetate. Electronic cigarettes (vapes) first made headlines due to skyrocketing sales and popularity. Then reports of serious illnesses and deaths from vaping tobacco and other substances began to increase in the summer of 2019. In mid-February 2020, the health authority CDC reported more than 2800 cases of lung injury requiring hospitalization in all 50 states, and 68 deaths. EVALI (vaping associated lung disease), as the disease is now called, continues to raise questions, although emergency department visits related to vaping have declined.
Why do vaping-related injuries, and even deaths, seem to happen so suddenly, even though e-cigarettes have been in use for years? Why is EVALI difficult to diagnose? What types of lung damage occur and what could be the causes? Why are only some people affected, while others continue to use vaping products with no apparent illness? And what do we know so far about the possible long-term consequences of vaping?
What is EVALI?
EVALI (e-cigarette or vaping product associated with lung injury) is an inflammatory response in the lungs triggered by inhalants. Considering a huge range of products, many illicit or counterfeit products, and many different ingredients, it is no surprise that EVALI also varies. It can occur as pneumonia, damage to small air pockets in the lungs (alveoli), or an inflammatory reaction called fibrinous pneumonitis.
Why is EVALI difficult to diagnose?
Confirming a diagnosis of EVALI is very difficult because no simple laboratory test is available. Right now, doctors are diagnosing EVALI based on symptoms, recent use of vaping products, abnormalities found on lung tests, and no signs of infection. Unfortunately, the direct lung exam requires bronchoscopy, which most patients are too ill to tolerate safely. Data from patients who have undergone bronchoscopy have so far failed to identify the mechanism causing lung damage.
What do we know about the causes of EVALI?
It is difficult to identify the causes of EVALI. There are thousands of vaping products with different ingredients, including some illicit substances. Most likely, several specific products or substances cause serious lung problems. No one knows why some people get EVALI and others don't, but it's likely due to the different ingredients they inhaled.
- The most common brand associated with EVALI is Dank Vape, a brand of THC-containing products.
- The exclusive use of products containing THC increases the risk of EVALI. (It is unclear whether people who used nicotine-only vapors were also exposed to vaping products containing THC or whether other ingredients caused lung damage.)
- Vitamin E acetate is strongly associated with EVALI. It is mainly found in counterfeit brands (and recently in Juul products from South Korea). Vitamin E is a supplement considered safe when ingested or applied to the skin. Vitamin E acetate is an oil derivative used in vaping products as a thickener. It is found in about half of the products associated with EVALI. A recent small study found deposits of vitamin E in the lung tissue of EVALI patients.
- Other chemical components, including triglycerides, vegetable oils, distillates, and dilute terpenes, have been found in bronchoscopy samples from EVALI patients. But none are present in all patients.
Potential long-term health concerns related to vaping
Naturally, serious illnesses and deaths from lung injury related to vaping have received a lot of attention. But it exists other causes of concern regarding the long-term health effects of inhaled vapors, including humectants, flavorings, the heating process and corrosion of metal coils.
- Humectants are additives used to produce steam, such as propylene glycol or glycerol. Human respiratory cells exposed to humectants in laboratory experiments show increased inflammation and reduced survival. This raises concerns about lung damage when people inhale humectants.
- Thousands of aroma products of vape have been reported. Because they are inhaled and not ingested, they are not regulated by the Flavor and Extract Manufacturers Association (FEMA). One example is diacetyl, which gives foods a buttery or creamy flavor. Factory workers exposed to high levels of diacetyl in popcorn factories have developed a lung injury known as “popcorn lung”, so it is regulated in the workplace by OSHA . Still, diacetyl is used in over 60% of sweet-flavored vapors, and only three to four puffs per day far exceed OSHA exposure limits.
- Heating ingredients to produce steam causes their chemical components to decompose, which can also be hazardous to health. For example, heating propylene glycol produces aldehydes, which expose users to five to 15 times the vapor levels of formaldehyde - a known carcinogen - found in tobacco cigarettes.
- In addition, repeated use of refillable cartridges may cause the metal heating coils to decompose, which may result in inhalation or ingestion of heavy metals. The toxic metals, manganese and zinc, have been isolated from used spray devices. These can cause illness when consumed at high levels. There are also case reports of lung damage linked to cobalt in vaping liquid. This has been attributed to the corrosion of the coils.
For now, the CDC and FDA strongly recommend that people avoid the use of e-cigarettes or vaping products that contain THC, especially in the illicit market. Health workers should report any suspected EVALI case to their state health department. In Massachusetts, new legislation prohibits the sale of all flavored tobacco products from June 2020 and imposes a tax on nicotine vaping products. The United States House and Senate have passed a bill banning the sale of tobacco and e-cigarettes to anyone under the age of 21. While these measures are a start, there is also a need to regulate the safety of ingredients in electronic cigarettes.
It's no surprise: previous research has shown that the culprit behind the injuries was probably vitamin E acetate, a substance used in black market vaporizers. If people could easily get legal cannabis, they would be less likely to turn to the black market.
To conduct the study, the researchers analyzed data from the Centers for Disease Control and Prevention on cases of electronic cigarette or vaporizer-associated lung injury (EVALI) in the states, taking into account the population and the prevalence of electronic cigarette use.
The study found that states with legal recreational clinics had 1,7 cases of EVALI per million people, while states that prohibit adult cannabis use had 8,1 cases per million. (States that only have cannabis for medical purposes recorded 8,8 cases of EVALI per million residents, which is not statistically significant).