This week, the Journal of the American Medical Association (JAMA) Network Open published a cross-sectional study that sought to measure whether states with legal cannabis saw fewer reports of electronic cigarette– or vaping–associated lung injuries (EVALI). The results showed that “recreational marijuana states had among the lowest EVALI rates of all states.”

The lack of information regarding the source (or sources) of the illnesses, captured headlines and caused a decline in vape sales last year. Nearly 3,000 cases of EVALI, and 60 vaping related deaths, had been reported as of February 2020.

The inspiration for the research came from reading EVALI reports, Indiana University researcher Coady Wing, who led the study, told Cannabis Wire.

“We thought about some of the things that often happen in black markets for illegal drugs. For instance, during the alcohol prohibition era, bootleg alcohol producers often made and sold alcohol products that were not that safe to drink. In more recent years, there are cases where black market sellers of illegal drugs like heroin try to increase profit margins by diluting drugs with other substances, which can be harmful,” Wing said.

“We thought that maybe something like that could be happening in EVALI situation. Perhaps people in states where recreational marijuana is legal tended to purchase marijuana products from the legal market and the legal market was not selling any marijuana vaping products that included vitamin E acetate.”

For this study, researchers from the O’Neill School of Public and Environmental Affairs at Indiana University, Bloomington, analyzed state-level CDC data, as well as e-cigarette consumption data from the Behavioral Risk Factor Surveillance System, and population data.

Researchers concluded that the “data suggest that EVALI cases were concentrated in states where consumers do not have legal access to recreational marijuana dispensaries.”

The natural question arose: was access to legal cannabis shops responsible for the lower EVALI numbers?

“The reason for this association is not yet clear. It is possible that in recreational states, people tend to purchase marijuana products at legal dispensaries, which may be less likely to sell the contaminated products that are thought to cause EVALI,” researchers wrote.

These findings are significant because, at the peak of reported instances of EVALI, there was plenty of confusion regarding whether consumers were buying these tainted vapes from legal or illegal sources. For example, in January, the Centers for Disease Control and Prevention released a report that found that 11% of vape-related lung illness patients reported sourcing THC-containing vape products from “commercial sources.” Specifically, a total of 8% of vape-related lung illness patients reported sourcing THC-containing vape products from “recreational dispensaries,” and 3% said they sourced these products from “medical dispensaries.”

When Cannabis Wire pressed the CDC on whether these “dispensaries” are defined as state-legal, regulated shops, CDC spokesperson LaKia Bryant said: “This is self-reported information from the individual patients during interviews, and it is not possible for us to verify from these data whether the source was licensed or not.”

So, in other words: they weren’t sure. Still, in response to that CDC report, the New York State Association of County Health Officials and the Medical Society of the State of New York released a full throated statement in January against the push for adult use legalization in the state.

“A troubling new report from the federal Centers for Disease Control and Prevention (CDC) has confirmed a direct link between legally obtained adult use cannabis and the nation’s outbreak of vaping related illnesses and deaths,” they wrote in their statement.

JAMA Network Open also published an invited commentary on the topic, which also focused on the parallel with alcohol prohibition, during which blindness was caused by illicit alcohol production.

“Uncertainty about the cause of EVALI remains, but ample evidence suggests that vitamin E acetate (VEA), a constituent of culprit vaping products, is the causative agent,” the authors wrote. The CDC previously zeroed in on vitamin E acetate, which is sometimes used as a thickening agent in illicit market vape products.

The authors continued, “Strong associations between the illness and use of THC-containing vaping products, especially those obtained from black-market sources, suggest that VEA is being used to dilute or stretch THC concentrates that constitute the active ingredient of the implicated products—a scenario reminiscent of the unscrupulous bootleggers of the Prohibition era.”

Indiana University researcher Ashley Bradford told Cannabis Wire that she and the other co-authors of the study were specifically interested in the intended and unintended outcomes of “prohibition policies.”

“While these types of laws are designed to reduce the use of specific drugs, one effect is that some consumers will be pushed into the black market, which is unregulated and thus inherently riskier.”

Bradford continued, “While we can’t speak to whether marijuana legalization is a net positive for society, what we can say is that that allowing consumers to legally purchase THC products is associated with fewer EVALI cases. These results, while simply cross sectional, do shed some light on the spill-over effects of prohibition policies.”

Wing told Cannabis Wire that the study was “very simple,” and reiterated that it’s important “not to read into the results too much.” Still, he added, “The size of the difference was surprising to me. Essentially, recreational marijuana states have about 6.4 to 7.1 fewer EVALI cases per million than the other states. That’s a big gap.”