E-Cigarettes Include “Concerning” Levels of Potential Carcinogen

Dentistry Today


A potential carcinogen that has been banned as a food additive is present in concerningly high levels in electronic cigarette liquids and smokeless tobacco products, according to researchers at Duke Health.

The Food and Drug Administration (FDA) banned pulegone, which is in menthol- and mint-flavored e-cigarettes and smokeless tobacco products, as a food additive last year because of its carcinogenic properties in response to petitions from consumer groups. However, the FDA does not regulate its presence in e-cigarettes and smokeless tobacco, which are promoted as safer alternatives to regular cigarettes.

“Our findings suggest that the FDA should implement measures to mitigate pulegone-related health risks before suggesting mint- and menthol-flavored e-cigarettes and smokeless tobacco products as alternatives for people who use combustible tobacco products,” said Sven-Eric Jordt, PhD, professor in the Department of Anesthesiology at Duke and lead author of the study.

Jordt and research partner Sairam V. Jabba, DVM, PhD, became interested in the topic because the Centers for Disease Control and Prevention (CDC) published studies showing that mint-flavored and menthol-flavored e-cigarette liquids and smokeless tobacco products marketed in the United States include substantial amounts of pulegone. 

The researchers analyzed whether several top brands of regular menthol cigarettes, three e-cigarette brands, and one smokeless tobacco brand include enough pulegone to be a cause for concern. They compared the CDC-reported amounts of pulegone with the FDA’s exposure risk data, including the levels at which exposure-related tumors were reported in animal studies. 

The analysis found that the levels in the e-cigarettes and smokeless tobacco exceeded the thresholds of concern. Regular menthol cigarettes included levels below the thresholds. 

“Our analysis suggests that users of mint- and menthol-flavored e-cigarettes and smokeless tobacco are exposed to pulegone levels higher than the FDA considers acceptable for intake in food and higher than in smokers of combustible menthol cigarettes,” Jordt said.

“The tobacco industry has long known about the dangers of pulegone and has continuously tried to minimize its levels in menthol cigarette flavorings, so the levels are much lower in menthol cigarettes than in electronic cigarettes,” said Jordt. 

E-cigarette manufacturers may be less familiar with the dangers and use cheaper ingredients to reduce costs, the researchers said. 

The researchers note that the FDA’s exposure risk calculations are based on oral exposure in animal studies. While these risks may apply to oral exposure through smokeless tobacco, they may differ from inhalation exposure through e-cigarette vapor. Also, there is no toxicity data available on exposure via inhalation, which is concerning because toxicologists consider the lung to be more sensitive to toxic chemicals than the digestive tract.

The study, “Risk Analysis for the Carcinogen Pulegone in Mint- and Menthol-Flavored e-Cigarettes and Smokeless Tobacco Products,” was published by JAMA Internal Medicine.

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