There is an ever growing body of scientific literature showing that the vapor from e-cigarettes are not harmless. The e-cigarette vapor has been shown to contain formaldehyde, glycidol, and other known carcinogens and has also been shown to contain the popcorn lung inducing compound diacetyl. It appears that there are two factors contributing to the potentially toxic effects of e-cigarettes. First, the voltage output from the battery. The higher the voltage, the hotter the e-liquid gets and the greater the chance that the components of the liquid are converted into toxic chemicals. Second, the flavorings added to the vapors to give them a greater appeal. The flavorings contain compounds that, when exposed to heat and vaporized, can undergo chemical reactions that turn them into toxic substances. While all the flavorings included in the e-liquid have been shown to be safe for human consumption, there is not information on their safety when they are heated and inhaled. A new paper, published in the journal Tobacco Control, shows that the flavorings found in e-liquids are toxic to the cells lining your airways.
In this paper, the researchers collected vapor samples from six different e-cigarettes and five different flavorings (Menthol, Tobacco, Pina Colada, Coffee, Strawberry) and exposed them to epithelial cells from the airways (these are the cells that line your airway). They also tested the effect of increasing voltage (increase heat) on the toxicity of the resulting vapor. When they exposed the cells to vapor from increasing voltages, they found that 40% of the cells died at the lowest voltage setting (3.3 volts) and at the highest setting 90% of the cells died (4.8 volts). In addition, increasing the voltage resulted in a large increase in the amount of inflammation in the cells. When the researchers began to test different flavorings, they found that the menthol, coffee, and strawberry flavorings had the biggest effect on the viability of the cells. In particular, 90% of the cells died when they were exposed to vapor containing strawberry flavoring at the lowest voltage setting. Also, the strawberry and coffee flavors caused a very strong increase in the amount of inflammation in the cells, similar to that caused by increasing the voltage. The other three flavors also caused cells to die and increase the amount of inflammation but not as much as strawberry or coffee flavoring.
This work is yet another piece of evidence against the rising use of e-cigarettes as a healthy alternative to traditional cigarettes. Death of the cells that line your airways exposes the underlying tissue to pollution, bacteria, and allergens that can lead to swelling, narrowing, and damage to the airways in your lung. It would not be surprising if e-cigarette usage resulted in another epidemic of COPD in 40 years similar to what we are currently seeing from traditional cigarette usage. The big problem with e-cigarettes is their uptake by youth. Since 2011, e-cigarette use has increased from 0.6% to 5.3% in middle school students across the US. These numbers are more troubling in high school where 16% of students reported using e-cigarettes, up from 1.5% in 2011. E-cigarettes are not harmless and we need legislation in place to protect our children from the potential of another smoking epidemic.
Image Credit: Flickr Daniel Riquelme