There has been a lot of attention to what elements of e-cigarette liquids cause e-cigarette and vaping induced lung injury (EVALI), the serious, and sometimes fatal, lung disease that was identified in vapers in the summer of 2019. There is now good evidence that vitamin E acetate, a chemical used to dilute THC in marijuana vapes, causes EVALI.
The Centers for Disease Control and Prevention, among others, have been careful to say that vitamin E acetate, however, may not be the only cause of EVALI. One reason for this is that while most EVALI victims used marijuana vapes, some only used nicotine e-cigarettes and most were dual users of nicotine and marijuana e-cigarettes.
Now Michael Kleinman and colleagues have identified an important new element in e-cigarettes cause EVALI-like serious lung injury in rats: the heating coil used to heat the e-liquid and generate the aerosol that vapers inhale. They found that while e-cigarettes with stainless steel heating coils did not cause immediate serious lung damage, the same e-cigarettes using the same e-liquid (which did not include vitamin E acetate) but with a nickel-chromium (nichrome) heating coil did.
Nichrome alloy is widely used in resistance heaters like toasters.
This work indicates that it is important to look beyond the e-liquid when assessing the risks of e-cigarettes. If this work is confirmed in future studies, it would also make a good case for the FDA to issue a product standard banning the use of nichrome heating coils in e-cigarettes and other new tobacco products. It also points to the need for the FDA to demand that companies applying to sell new tobacco products that are heated electrically to demonstrate that the heating element is safe.
The paper, “E‐cigarette or Vaping Product Use–Associated Lung Injury Produced in an Animal Model From Electronic Cigarette Vapor Exposure Without Tetrahydrocannabinol or Vitamin E Oil,” is freely available here.
Here is the abstract:
E‐cigarette or vaping product use–associated lung injury was recognized in the United States in the summer of 2019 and is typified by acute respiratory distress, shortness of breath, chest pain, cough, and fever, associated with vaping. It can mimic many of the manifestations of coronavirus disease 2019 (COVID‐19). Some investigators have suggested that E‐cigarette or vaping product use–associated lung injury was due to tetrahydrocannabinol or vitamin E acetate oil mixed with the electronic cigarette liquid. In experimental rodent studies initially designed to study the effect of electronic cigarette use on the cardiovascular system, we observed an E‐cigarette or vaping product use–associated lung injury‐like condition that occurred acutely after use of a nichrome heating element at high power, without the use of tetrahydrocannabinol, vitamin E, or nicotine. Lung lesions included thickening of the alveolar wall with foci of inflammation, red blood cell congestion, obliteration of alveolar spaces, and pneumonitis in some cases; bronchi showed accumulation of fibrin, inflammatory cells, and mucus plugs. Electronic cigarette users should be cautioned about the potential danger of operating electronic cigarette units at high settings; the possibility that certain heating elements may be deleterious; and that E‐cigarette or vaping product use–associated lung injury may not be dependent upon tetrahydrocannabinol, vitamin E, or nicotine.
The full citation is: Kleinman MT, et al. E‐cigarette or Vaping Product Use–Associated Lung Injury Produced in an Animal Model From Electronic Cigarette Vapor Exposure Without Tetrahydrocannabinol or Vitamin E Oil. Journal of the American Heart Association 2020: https://doi.org/10.1161/JAHA.120.017368.