A new study involving nearly 35,000 women published Thursday in Stroke: Journal of the American Heart Association suggests that drinking coffee may lower the risk of stroke.
Susanna Larsson of the Karolinska Institute in Stockholm, who led the research, followed women aged 49 to 83 for an average of 10 years, and found that those who drank more than one cup of coffee a day had a 22% to 25% lowered risk of stroke, compared with women who drank less. Further, the study found, drinking little or no coffee was actually associated with a slight increase in stroke risk.
Larsson said, “Some women have avoided consuming coffee because they have thought it is unhealthy…In fact, increasing evidence indicates that moderate coffee consumption may decrease the risk of some diseases such as diabetes, liver cancer and possibly stroke.” But authors caution that more evidence is needed. The women in the study were not asked whether they drank decaf or regular coffee, but most Swedes drink caffeinated coffee, Larsson noted.
This study actually came from the participants of the Swedish Mammography Cohort, a long-term study focusing on the associations between diet, lifestyle and disease. Researchers collected data on women's coffee consumption and incidence of stroke between 1998 and 2008. There were 1,680 cases of stroke during that time period, with a reduced risk among women who drank coffee. Women who drank five or more cups had the same reduction in stroke risk as women who drank one to two cups, compared with those who drank less. Researchers took into account smoking, drinking, weight, diabetes and blood pressure.
The reason for the association is not specified but researchers speculated that it might reduce inflammation or improve insulin resistance, which may help lower risk for stroke.
Dr. Larry B. Goldstein, director of the Duke Stroke Center at Duke University Medical Center said that the main problem with this type of study is that there are too many factors unaccounted for and association does not prove causality. He explained, “Subjects were asked about their past coffee consumption in a questionnaire and then followed over time. There is no way to know if they changed their behavior.” He suggested that there are other factors that could have affected the results.
“Coffee drinkers should rejoice,” said Dr. Sharonne N. Hayes, a cardiologist at Mayo Clinic in Rochester, Minn. “Coffee is often made out to be potentially bad for your heart. There really hasn't been any study that convincingly said coffee is bad…If you are drinking coffee now, you may be doing some good and you are likely not doing harm,” she added.
Dr. David S. Seres, director of medical nutrition at Columbia University’s College of Physicians and Surgeons in New York said, “These sorts of epidemiological studies are compelling but they don’t prove cause.” Dr. Cathy Sila, a stroke neurologist at University Hospitals Case Medical Center in Cleveland added, “There hasn’t been a consistent message come out,” of coffee studies.
Larsson and others point out that those who want to reduce their chances of a stroke should focus on the proven ways to lower risk - stop smoking, control blood pressure and maintain a healthy weight.
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