An expert on tobacco harm reduction underscored the findings of a new study showing that the cancer-causing risk posed by e-cigarettes was five orders of magnitude (57,000-fold) lower than conventional cigarettes, and was also lower than the guideline values defined by the U.S. Environmental Protection Agency (EPA) and World Health Organization (WHO).
In the study published online on October 18, 2017 in the Journal of Aerosol Science, Italian researchers measured both the aerosol emitted from e-cigarettes and the exposure to secondhand e-cigarette smoke in a typical indoor environment in terms of particle number and surface area concentrations.
Dr. Konstantinos E. Farsalinos highlighted the new study in his scientific blog “E-Cigarette Research”. A research fellow at the Onassis Cardiac Surgery Center in Athens, Greece, and at the Department of Pharmacy, University of Patras, Greece, Farsalinos has been conducting research on e-cigarettes as principal investigator since 2011. As of 2016, he has published more than 40 studies and articles in international peer-reviewed scientific journals about smoking, tobacco harm reduction, and e-cigarettes.
There is an ongoing debate over whether vaporized nicotine products (VNPs), such as e-cigarettes, are less harmful than smoking. E-cigarettes function by heating a nicotine-containing liquid. Studies have shown that VNPs can expose people to cancer-causing agents; the question has been how much cancer risk VNPs pose.
Farsalinos noted that the Italian study supports the findings of another recent study by Scottish researchers. A team of researchers led by Dr. William Stephens of the University of Saint Andrews in Scotland determined the cancer risk of the individual compounds in VNPs, and then calculated an overall VNP cancer risk. They looked at published analyses of emissions to generate cancer-risk figures for a number of nicotine-delivering aerosols, including cigarettes, e-cigarettes, heat-not-burn, and medicinal nicotine inhalers. To compare risk across the aerosols, they then came up with a unit of measurement called inhalation unit risk, which they defined as the risk of developing cancer per unit of chemical inhaled. The team then linked the inhalation unit risk with smokers’ estimated daily consumption to arrive at final risk figures.
The study found that each of the aerosols had different cancer potencies. Cigarette smoke had the highest potency. Most e-cigarettes had cancer potencies that were less than 1 percent of cigarette smoke. The study, “Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke,” was published a few months ago in the journal Tobacco Control.
“E-cigarettes are much safer than conventional cigarettes because e-cigarettes heat and vaporize liquid at lower temperatures reaching only 180ºC to 250ºC. Unlike tobacco cigarettes, e-cigarettes do not burn organic matter at very high temperatures of over 800ºC, which produces many poisonous chemicals such as carbon monoxide, formaldehyde, ammonia, hydrogen cyanide, arsenic, DDT, which are subsequently inhaled by the smoker,” Farsalinos explained
He added that the main components of the liquid used in e-cigarettes (“e-liquid”) are propylene glycol and glycerin, accounting for 95% of the e-liquid. The remaining components are water, nicotine, and food-grade flavorings.