High Cholesterol Alone Raises Women's Stroke Risk

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HERE'S ANOTHER REASON for women to watch their cholesterol levels: A new analysis of data from the Women's Health Study has found that women with elevated cholesterol levels had twice the risk for ischemic stroke compared to women with the lowest cholesterol levels, even when the subjects had no prior history of heart disease or stroke.

While previous studies have established a conclusive link between cholesterol and coronary heart disease, the evidence for ischemic stroke--the most common type of stroke--was less clear. Also, studies in this area typically included only men or only individuals with pre-existing coronary heart disease.

The new analysis, published in the journal Neurology, looked at the incidence of ischemic stroke among the nearly 28,000 healthy female healthcare professionals, age 45 and above, participating in the Women's Health Study. Lead author Tobias Kurth MD, ScD, of Brigham and Women's Hospital in Boston and his colleagues compared data on the women's baseline lipid levels and their incidence of stroke over an 11-year period. The study controlled for other factors such as alcohol consumption, exercise, smoking, body mass index (BMI), hormone replacement therapy and other drug and supplement regimens. The subjects suffered 282 ischemic strokes--just over nine strokes per 10,000 women per year.

The strongest predictor of ischemic stroke, the researchers found, was non-HDL type cholesterol--that is, cholesterol levels excluding the "good" HDL--followed by total cholesterol. Even when subjects had no prior history of heart disease or stroke, the risk of ischemic stroke among women with elevated cholesterol rose uniformly with their lipid levels.

The researchers acknowledged that the study was limited in that there was only one measurement of lipid levels per woman and by the absence of data on the use of cholesterol-lowering medication during follow-up. Also, because nearly 95% of the women were white, the researchers noted that the findings might not generalize to more diverse populations. Still, they said, the biologic mechanisms of high cholesterol levels were likely to be similar in other populations.

The researchers concluded that their data, along with that of previous studies, "strongly support the notion that lipids are a biologic risk factor for ischemic stroke and that avoiding unfavorable cholesterol levels may help to prevent ischemic stroke." That's a recommendation also noted by both the American Heart Association and the American Stroke Association in their prevention guidelines. The American Heart Association endorses the National Cholesterol Education Program (NCEP) cholesterol guidelines of maintaining a total cholesterol count of 200 mg/dL or less, with a level of 60 mg/dL and above of HDL cholesterol and 100 mg/dL or less of LDL ("bad") cholesterol.

In their published results, the researchers said their analysis shows the connection between cholesterol and ischemic stroke, and the importance for all women to maintain healthy cholesterol levels.

"Avoiding unfavorable cholesterol levels may help to prevent ischemic stroke," Dr. Kurth said. "This is also true for apparently healthy women."

TO LEARN MORE: Neurology, Feb. 20, 2007; abstract at . American Heart Association ; American Stroke Association .

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