Menthol Cigarettes Associated With Higher Stroke Risk

Smokers of menthol cigarettes are more than twice as likely to suffer a stroke than regular cigarette users according to the results of a study published this month in the Archives of Internal Medicine.

The research, conducted by Dr Nicholas Vozoris of the Department of Medicine, St Michael’s Hospital, Toronto, involved the study of more than 5,000 smokers from the 2001-2008 NHANES study. Around a quarter of study participants normally smoked mentholated cigarettes.

Vozoris found that compared to regular smokers, mentholated cigarette smokers were 2.25 times more likely to suffer a stroke after adjustment for age, race, sex, education, income, BMI, smoking intensity, and duration. The risks were particularly high for non-blacks and women who had a more than 3-fold increase in stroke risk.

On the other hand, the researchers found no additional risks of hypertension, myocardial infarction, congestive heart failure, or chronic obstructive pulmonary disease (COPD) in menthol cigarette users compared to regular smokers.

Hypertension is the most significant risk factor for strokes with hypertensive individuals more than 4 times more likely to suffer a stroke than those with a normal blood pressure. It is therefore interesting to note that stroke risk increased in menthol cigarette smokers despite no apparent increase in blood pressure suggesting other mechanisms are responsible for the increased stroke risk.

Menthol tends to have a localized anaesthetic effect on the throat as well as stifling the cough reflex. This results in menthol smokers inhaling more deeply and holding the tobacco smoke in their lungs for longer than regular cigarette smokers. The differences in smoking behaviour between menthol and regular cigarette users could explain some of the increased stroke risk however it is unclear why the risk of other cardiovascular diseases wouldn’t also increase.

Vozoris also noted that mentholated cigarettes have been associated with decreased elasticity of the carotid artery which has been linked to an increased risk of ischemic stroke in some studies.

Other studies have found elevated carbon monoxide levels in users of mentholated cigarettes. A 1994 study, published in the journal Experimental and Clinical Psychopharmacology found that carbon monoxide concentrations in the exhaled air of cigarette smokers increased as menthol concentration increased. Mean carbon monoxide levels increased from 5.6ppm for non-menthol cigarettes, to 6.1ppm for cigarettes containing 4mg of menthol, and to 8.1ppm for cigarettes containing 8mg of menthol.

Menthol cigarettes were first introduced in the 1920s by the Axton-Fisher Tobacco Company and have gradually gained market share around the world, particularly in developing countries. They currently make up a 27% share of the USA manufactured cigarette market (as measured by volume of cigarette shipments) however market share is as high as 60% in the Philippines and 30-40% in Cameroon.

In the United States, menthol cigarettes are very popular amongst African Americans with 78% smoking predominantly menthol cigarettes. Women, occasional smokers, poorer individuals, and those aged under 18 also have high levels of menthol cigarette usage.