Drinking Coffee May Reduce the Risk of Stroke

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Coffee consumption and risk of stroke in women, by Esther Lopez-Garcia and colleagues. Circulation 119:1116–1123, 2009

What is the problem and what is known about it so far?

Many researchers have tried to find out whether drinking coffee is healthy or unhealthy. Some studies have shown that drinking coffee may protect against type 2 diabetes. A recent study suggested that drinking coffee does not increase a person's chances of getting heart disease. Very little is known about whether coffee affects a person's chances of having a stroke. A stroke occurs when blood supply to part of the brain is interrupted and brain tissue is damaged. Strokes can result in paralysis, problems with thinking or speaking, and emotional problems.

Why did the researchers do this particular study?

The researchers wanted to find out if drinking coffee has either a good or a bad effect on the risk of having a stroke.

Who was studied?

The study included more than 83,000 women who participated in the large, long-term Nurses' Health Study and who did not have a history of stroke, heart disease, diabetes, or cancer at the start of that study.

How was the study done?

The participants in the Nurses' Health Study were asked about their coffee consumption at the start of the study in 1980 and then every 2 to 4 years through 2004. Researchers also gathered information about how many women suffered strokes during those years. They analyzed the information statistically to account for many other factors, such as age, smoking status, weight, exercise, and others, as well as presence of medical conditions such as high blood pressure, blood fat (cholesterol) problems, and diabetes.

What did the researchers find?

Drinking moderate to large amounts of coffee did not increase the chances of having a stroke for women. For those who did not have high blood pressure or high cholesterol and did not smoke, drinking coffee modestly reduced the chances of having a stroke. Decaffeinated coffee had similar effects, but tea and other caffeinated beverages did not.

What were the limitations of the study?

Because researchers relied on patients' self-reports, some of the information collected may have been incorrect. Also, although the study took many factors into account, there may have been other factors that affected the results and were not taken into account.

What are the implications of the study?

Drinking coffee does not appear to increase a person's chances of having a stroke and may even reduce the chances of having stroke for some people. However, we do not yet know how or why this is true, and more research is needed.

FOR MORE INFORMATION

Coffee and diabetes

All about stroke

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