A new study has found that smokers of mint and menthol flavoured e-cigarettes and smokeless tobacco are exposed to higher levels of a carcinogen than smokers of menthol cigarettes, i newspaper reported.

A new study by researchers at Duke University School of Medicine has examined the cancer risk of pulegone, a clear colourless oily liquid with a peppermint odour, as a component in menthol-flavoured e-cigarettes and smokeless tobacco products. Their analysis suggests that users are exposed to pulegone levels higher than the FDA considers unacceptable for intake of synthetic pulegone in food, and higher than in smokers of combustible menthol cigarettes, the report said.
"Although pulegone is toxic in humans, it is unknown if users of combustible tobacco products, smokeless tobacco, or e-cigarettes absorb and metabolize the quantities associated with production of a carcinogenic effect," the study said. "Nevertheless… our findings appear to establish health risks associated with pulegone intake and concerns that the FDA should address before suggesting mint and menthol-flavoured e-cigarettes and smokeless tobacco products as alternatives for people who use combustible tobacco products."
British experts pointed to limitations in the study. Paul Aveyard, Professor of Behavioural Medicine at the University of Oxford, was quoted as saying: “It is not possible from this [study] to assess whether people who vape menthol flavours have excess exposure to pulegone. A study to examine whether there is a concern would measure pulegone concentrations in people who vaped, but the authors have not done this.”
In the UK, menthol cigarettes are in a four-year phase-out period before being banned in May 2020 to discourage younger people from smoking.