New Study Casts Doubt on the Role of Oils in Vape Illnesses

One of the scariest things about the ongoing outbreak of vaping-associated pulmonary injuries is that it’s a public health crisis born of so many unknowns. We still don’t know exactly what vape juice is made out of. We don’t know if e-cigarettes are the primary culprit or just the culprit regulators can control, given initial reports that the majority of vape-related illnesses were linked to illicit market THC cartridges, not e-cigarettes. And we don’t know what mechanism of vaping is actually making people sick; we only know for sure that it’s been connected to 15 deaths and counting, along with hundreds of hospitalizations.

Until now, the most prominent recent theory attributed the illnesses to oils like vitamin E acetate, which are in vape juice as an additive. The idea was that lipids, or fatty acids inhaled from the oil, was coating the lungs once inhaled, triggering cell death and pneumonia-like symptoms. Flavoring additives, pesticides, and heavy metals have also raised concerns and been cited as potential culprits, especially when patients complained of lung issues after using illicit market THC cartridges.

But a biopsy review of a small group of 17 subjects with a history of vaping released Wednesday by researchers at the Mayo Clinic didn’t find that kind of lung damage, leading researchers to posit an alternative cause for the pulmonary injuries: “direct toxicity or tissue damage from noxious chemical fumes,” per a press release. The authors noted specifically that they didn’t see signs of oils causing the problems in their test subjects. “While it is difficult to discount the potential role of lipid,” they wrote, “Vaping-associated lung injury represents a form of airway-centered chemical pneumonitis from one or more inhaled toxic substances rather than exogenous lipoid pneumonia per se, but the agents responsible remain unknown.”

The scientists who conducted the review said they found their results promising, especially when it comes to diagnostics. “We were not surprised by what we found, regarding toxicity," Dr. Larsen, senior author of the study, said in the press release. "We have seen a handful of cases, scattered individual cases, over the past two years where we've observed the same thing, and now we are seeing a sudden spike in cases. Our study offers the first detailed review of the abnormalities that may be seen in lung biopsies to help clinicians and pathologists make a diagnosis in an appropriate clinical context.”

But because this latest review looked at biopsies from only 17 patients, the scientists acknowledged that their results “provide preliminary insight” only and that more data accumulation is necessary to draw firm conclusions. It’s hard to feel confident that these results will provide a tidy solution to the vape crisis—if such a solution even exists. For now, if you’re happy with your current level of lung health, it’s probably smart to shelve your vape pen until someone figures out what the hell is actually going on.

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