Menthol cigarettes helped recruit an estimated extra 10 million US smokers between 1980 and 2018, reveals the first study of its kind, published online in the journal Tobacco Control.
And these products were responsible for 378,000 premature deaths and a cumulative total of 3 million years of life lost during this period, estimate the researchers.
Menthol cigarettes were first created in 1926 but only started to become widely used between 1957 and 1962.
Because menthol produces a cooling sensation in the throat and airways, so curbing the irritation and harshness of cigarette smoke, mentholated cigarettes are thought to encourage young people to start smoking as well as make it harder for smokers to quit.
The 2009 Family Smoking Prevention and Tobacco Control Act gave the US Food and Drug Administration (FDA) the power to ban menthol in cigarettes, but this power hasn't yet been exercised.
As no study to date has quantified the other damage that menthol cigarettes have wrought among US smokers, the researchers sought to estimate the numbers of excess smokers and lives lost due to menthol cigarettes between 1980 and 2018 in the US.
They did this, using a well-established simulation model of smoking prevalence and health effects (the Mendez-Warner model), to reproduce the observed smoking rates and associated deaths between 1980 and 2018, drawing on data from the National Health Interview Survey (NHIS).
Using the same model, these estimates were then recast, as if menthol cigarettes hadn't been on the market during that period, and both sets of estimates were compared to try and quantify the public health harms attributable to menthol cigarettes between 1980 and 2018.
The calculations indicated that the availability of menthol cigarettes had slowed the fall in smoking prevalence by 2.6 percentage points. It would have fallen from just over 33% in 1980 to just over 11% in 2018, instead of which it was nearly 14% in 2018.
The calculations also indicated that menthol cigarettes had been responsible for 10.1 million extra smokers (266,000 every year), 3 million cumulative years of life lost, and 378,000 premature deaths (9900 every year) between 1980 and 2018.
This study was designed to produce estimates for the US general public, so may not be more widely applicable, caution the researchers.
But they suggest that their findings "indicate that these products have had a significant detrimental impact on the public's health and could continue to pose a substantial health risk," write the researchers, adding that the harms affect all age groups.
The findings may help the FDA to devise potential regulations for mentholated tobacco products, they suggest.
External peer review? Yes
Evidence type: Modelling study