Summary
Introduction:
This article applies the Bradford hill criteria to the association between Vitamin E acetate (VEa) and e-cigarette, or vaping, product use-associated lung injury (EVaLI) to clarify the strength of the causal argument. The Bradford hill criteria are a set of guidelines used to assess whether an epidemiologic association is causal. The criteria include strength of association, consistency, specificity, temporality, biological gradient, plausibility, coherence, and experimental evidence.
Key Points:
* VEa is strongly associated with EVaLI patients, as 94.1% of bronchoalveolar lavage (BaL) tests from EVaLI patients have been positive for VEa, while 0% of tested BaLs from individuals without EVaLI from 2016 to 2019 have been positive.
* however, VEa is not consistently found in all EVaLI patients, and it is unclear whether VEa is the sole cause of EVaLI or if other chemical constituents of vaping fluid may also be responsible.
* There is a temporal relationship between the appearance of VEa in vaping products and the outbreak of EVaLI.
* Basic science testing and animal toxicity data are needed to support the theoretical mechanisms of VEa toxicity.
* There is a lack of direct experimental data on the toxicity of VEa administered via vaporization and its subsequent effect on pulmonary tissue.
* a systematic review of evidence regarding Vitamin E, or pyrolyzed Vitamin E acetate, exposure and the effect on biologic tissue may provide more comprehensive data for VEa-induced lung injury to be coherent with current knowledge.
Main Message:
This article highlights the need for systematized approaches to rapidly identify the cause of mass poisoning events of previously unknown etiology. The authors suggest that a systematic review of evidence regarding Vitamin E, or pyrolyzed Vitamin E acetate, exposure and the effect on biologic tissue may provide more comprehensive data for VEa-induced lung injury to be coherent with current knowledge. additionally, basic science testing and animal toxicity data are needed to support the theoretical mechanisms of VEa toxicity, and direct experimental data on the toxicity of VEa administered via vaporization and its subsequent effect on pulmonary tissue is lacking. Overall, the authors argue that further research is needed to strengthen the causal argument between VEa and EVaLI.
Citation
Feldman R, Meiman J, Stanton M, Gummin DD. Culprit or correlate? an application of the Bradford hill criteria to Vitamin E acetate. archives of toxicology. 2020;94(6):2249-2254. doi:10.1007/s00204-020-02770-x
