(HealthDay) -- Menthol cigarettes may pose an even greater risk for stroke than other types of cigarettes, especially for women and non-black smokers, says a new, large study.
In the latest look at the hazards of menthols vs. regular cigarettes, Canadian researchers found the stroke risk for those who smoked menthols was more than twice that for regular-cigarette smokers. And for women and non-blacks, the risk was more than three times higher.
But no elevated risk was seen between mentholated cigarette smoking and high blood pressure, heart attack, heart failure and the lung disease chronic obstructive pulmonary disease (COPD), the researchers said.
Exactly how, or if, smoking menthol cigarettes raises risk of stroke more than other cigarettes types is not fully understood.
"One potential mechanism is that menthol stimulates upper-airway cold receptors, which can increase breath-holding time, which may in turn facilitate the entrance of cigarette particulate matter into the lungs," said study author Dr. Nicholas Vozoris of St. Michael's Hospital, in Toronto. "Why smoking mentholated cigarettes would not result in an increase in forms of cardiopulmonary disease, other than stroke, is not clear."
The findings appear in a research letter published April 9 in the Archives of Internal Medicine.
Blacks are more likely to smoke menthol cigarettes than white smokers, but their stroke risk was lower in this study compared to non-blacks. "While this group has higher risk for stroke than Caucasians in general, this study found that the increased stroke risk among mentholated cigarette smokers was actually driven by non-African Americans, and not African-Americans," he said.
The findings should not be interpreted as any one type of cigarette is safer than any other. "There is no 'good' cigarette type," Vozoris said. "Smoking any kind of cigarette is bad for one's health, and serves to increase one's risk for a variety of cancers, heart diseases and lung diseases. However, this study shows that smoking mentholated cigarettes may place one at even higher risk for stroke than smoking regular, non-mentholated cigarettes."
To date, research on menthol cigarettes has been inconclusive. Last year, a U.S. Food and Drug Administration advisory panel said a ban on mentholated cigarettes might benefit the public health because the minty flavor seems to help people take up smoking more readily. However, the panel did not conclude that menthols were more harmful than regular cigarettes in terms of risks for lung cancer or other respiratory ailments.
Shortly after that recommendation was made, a study published in the Journal of the National Cancer Institute reported that people who smoke menthol cigarettes might even have a somewhat lower risk of developing and dying from lung cancer than other smokers.
For this new study, the researchers used data from the 2001-2008 U.S. National
Health and Nutrition Examination Surveys on more than 5,000 smokers age 20 and older. About 26 percent said they usually smoked menthols.
The researchers found that stroke risk associated with smoking menthols was 2.25 times higher compared to regular smokers; 3.28 times higher for women, and 3.48 times higher for non-blacks.
However, Vozoris said the new study has several limitations. The researchers didn't account for drug treatment that might have affected the findings, and the smoking habits were self-reported. Also, former smokers weren't included in the data.
Dr. Clinton Wright, an associate professor of neurology at the University of Miami Miller School of Medicine, said that more study is needed before any conclusions can be drawn about specific health risks associated with specific types of cigarettes. "Very little work has been done on mentholated cigarettes," he said.
Also, the new study "only shows an association, it does not show any cause and effect," he added.
Still, "mentholation may have chemicals involved in the process that may carry their own risks," he said. As to the finding that this elevated stroke risk was driven by whites, Wright said that the study may not have had enough blacks to pick up on a higher risk in this group.
The U.S. Centers for Disease Control and Prevention has more on the ills of smoking.