What the EVALI epidemic means for public health

The jury is out: vaping, or e-cigarette use, is a national epidemic in the U.S.

Thousands of cases of e-cigarette or vaping product use-associated lung injury, dubbed EVALI by scientists, have been reported to the CDC since last fall, Brian A. King, PhD, and colleagues at the CDC wrote in the New England Journal of Medicine. Cases have cropped up in all 50 states, the District of Columbia, Puerto Rico and the U.S. Virgin Islands, and as of early January, 57 deaths from EVALI had been confirmed.

The U.S. Surgeon General first declared war on vaping—teen vaping, in particular—in December 2018. At the time, e-cigarette use was again on the rise among middle and high school students after a 900% jump in prevalence between 2011 and 2015 and a short period of decline in 2016. By 2019, 5.2 million adolescents in the U.S. reported using either nicotine or THC-containing vaping products, including more than a quarter of high school students and more than a tenth of middle school students.

“In contrast, current use among adults remained unchanged from 2014 to 2017, and in 2018, 3.2% of U.S. adults reported current use of e-cigarettes,” King et al. wrote. “Use of these products among young people is driven by multiple factors, including advertising, attractive flavors and the availability of easily concealable devices that deliver high levels of nicotine.”

Not your grandma’s vape pen

Part of the public health scare surrounding EVALI concerns the potency of today’s products, King and colleagues said—especially when it comes to THC vapes. An increasing number of U.S. states are jumping on the legalized cannabis train, a shift the authors said “coincided with changes in the public perception of risk, the availability of a wide variety of products containing THC or cannabidiol (CBD), and increases in marijuana use among adults.”

There’s still a lot we don’t know about the health implications of marijuana, but what we do know ranges from positive (it relieves chronic pain) to negative (it can boost a person’s heart rate). One thing scientists are certain of, though, is that THC products have gotten a lot stronger since they last dominated American culture in the 60s. According to a study published in Missouri Medicine in 2018, there was a 212% increase in THC content in the marijuana flower between 1995 and 2015, and with more potent strains come more potent health risks.

Marijuana isn’t alone in this shift, though. While many cases of EVALI have been linked to THC products, others have occurred in patients who exclusively use nicotine vaping products. King and co-authors explained that devices that once mimicked the size and shape of a traditional cigarette have adopted slim, hideable designs, like Juul’s USB-like “pod mod,” which have made them more attractive to young people.

Pod mods like Juul also deliver nicotine in the form of nicotine salts, the authors said, which allow high levels of nicotine to be inhaled more easily than the free-base nicotine used in older e-cigarettes. One of Juul’s pod mods includes about as much nicotine as a 20-pack of cigarettes.

“Against this backdrop, the United States is seeing what can be considered two distinct but related epidemics with vaping: the recent outbreak of lung injuries and the continued surge in use by young people,” King and colleagues wrote. “The implementation of interventions aimed at curbing these epidemics should take into consideration their underlying drivers.”

Two epidemics

Both epidemics—EVALI and youth vaping—predominantly affect young people, the authors said, and have multiple causes, but they also differ from one another.

The EVALI epidemic, for one, primarily affects young adults between the ages of 18 and 34. That’s also the age bracket with the highest rates of marijuana use in the U.S., and EVALI outbreaks have been tied time and again to the use of illegally or informally obtained THC products. On the other hand, the youth vaping epidemic mainly concerns kids younger than 18 and is driven by the use of nicotine-containing products that are largely obtained legally from retailers.

Officials at the local, state and federal levels have been scrambling to control the epidemics, often basing their strategies on ones established decades ago to control tobacco abuse. Last June, San Francisco—Juul’s hub—became the first U.S. city to ban e-cigarette sales, and other regions have taken action to prohibit the use of e-cigs in indoor public areas, restrict young peoples’ access to vapes in retail settings and develop educational campaigns.

Recent research has tried to pinpoint a singular culprit behind EVALI and found a candidate in vitamin E acetate, a synthetic form of vitamin E that’s used as a thickening agent in THC-containing vaping products. Lab tests of bronchoalveolar-lavage  fluid samples from 51 patients with EVALI found THC in most samples and vitamin E acetate in all samples, but there’s not sufficient evidence to formally link the chemical to lung disease.

King and colleagues said that no matter the future focus of experts’ work on vaping, research on these epidemics will need to be “grounded in science and must target the underlying drivers.”

“The EVALI and youth vaping epidemics warrant immediate and decisive action to protect public health,” the team wrote. “The use of vaping products among young people is unsafe, regardless of whether they contain nicotine or THC. Both marijuana use and nicotine use can harm brain development through young adulthood; starting to use these substances at a younger age also increases the risk of tobacco and cannabis use disorders later in life. The risks posed by these products are further compounded by the emergence of EVALI.”

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