March 27, 2012 — Light to moderate alcohol consumption is associated with a lower risk for both ischemic and hemorrhagic stroke in women, new research suggests.
"Alcohol consumption in moderation has been consistently associated with lower risk of heart disease, but the data for stroke, especially with regard to stroke type, has been a matter of debate," lead author Monik Jimenez, ScD, from Brigham and Women's Hospital, Boston, Massachusetts, told Medscape Medical News.
The study is published online March 8 in Stroke.
The investigators examined data on 83,578 women in the Nurses' Health Study who were free of diagnosed cardiovascular disease and cancer at baseline. The participants were followed from 1980 to 2006.
Participants provided information about their use of alcohol at baseline and then every 4 years thereafter. They also provided information about lifestyle factors and stroke events every 2 years.
Strokes were classified according to the National Survey of Stroke criteria.
During the study period, there were 2171 incident strokes. Of these, 1206 were ischemic strokes, 363 were hemorrhagic strokes, and 602 were of unknown etiology.
About 30% of the women reported that they never drank alcohol, 35% reported very low levels of consumption (less than 4.9 g/day, or half a glass of wine per day), and 37% drank moderately (5 - 14.9 g/day, or ½ to 1 ½ glasses of wine, 1 mixed drink, or 1 beer daily).
Analysis of the data showed that women who consumed low to moderate amounts of alcohol had a lower risk for total stroke compared with women who never drank.
After adjusting for a number of variables, including smoking, physical activity, body mass index, family and personal history of heart disease, diabetes, hypertension, bilateral oophorectomy, postmenopausal status, hormone therapy, high cholesterol, multivitamin intake, aspirin, composite 6-nutrient diet score, highest level of education, husband's highest level of education, and marital status, the relative risks of stroke were 0.83 (95% confidence interval [CI], 0.75 - 0.92) for women who consumed < 5 g/day, 0.79 (95% CI, 0.70 - 0.90) for 5 to 14.9 g/day, 0.87 (95% CI, 0.72 - 1.05) for 15 to 29.9 g/day, and 1.06 (95% CI, 0.86 - 1.30) for 30 to 45 g/day. Results were similar for ischemic and hemorrhagic stroke.
The estimated risk for stroke in the highest category of reported alcohol intake did not reach statistical significance because there were very few heavy drinkers in the cohort, Dr. Jimenez pointed out.
"Moderate alcohol intake was associated with reduced risk of total stroke, and higher levels were not associated with reduced risk in this particular population, which really emphasizes the importance of moderation if you drink," she said.
"There are several ways that alcohol might reduce the risk of stroke," Dr. Jimenez speculated. "Alcohol has components which prevent blood clots and promote HDL cholesterol, which is the good cholesterol. But alcohol is like a double-edge sword because higher levels can increase high blood pressure and promote atrial fibrillation, which are also risk factors for stroke."
Dr. Jimenez stressed that women who currently do not drink should not start to drink in the belief that this will protect them from stroke.
"Our results are very much in line with the American Heart Association guidelines for up to a glass a day for women, but those recommendations are for women who are current drinkers, and we do not advocate the initiation of alcohol consumption for women who abstain from drinking," she said.
"This paper was based on a very well-done analysis with excellent ascertainment of alcohol exposure," R. Curtis Ellison, MD, professor of medicine at Boston University School of Medicine in Massachusetts, told Medscape Medical News.
"The findings from this study are not that new. Many studies have shown that stroke is in general 10, 15, 20% lower in moderate drinkers," Dr. Ellison said.
"But you have to keep supporting these findings because people are always looking for flaws. Out of 200 or 300 papers, there have been about half a dozen that have not found this, so you have to reinforce your findings. This is a very large study, and it is very useful to have such confirmation."
Dr. Jimenez and Dr. Ellison have disclosed no relevant financial relationships. Dr. Ellison reports that he is a member of the International Scientific Forum on Alcohol Research. The study was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health and the National Cancer Institute.
"Alcohol consumption in moderation has been consistently associated with lower risk of heart disease, but the data for stroke, especially with regard to stroke type, has been a matter of debate," lead author Monik Jimenez, ScD, from Brigham and Women's Hospital, Boston, Massachusetts, told Medscape Medical News.
The study is published online March 8 in Stroke.
The investigators examined data on 83,578 women in the Nurses' Health Study who were free of diagnosed cardiovascular disease and cancer at baseline. The participants were followed from 1980 to 2006.
Participants provided information about their use of alcohol at baseline and then every 4 years thereafter. They also provided information about lifestyle factors and stroke events every 2 years.
Strokes were classified according to the National Survey of Stroke criteria.
During the study period, there were 2171 incident strokes. Of these, 1206 were ischemic strokes, 363 were hemorrhagic strokes, and 602 were of unknown etiology.
About 30% of the women reported that they never drank alcohol, 35% reported very low levels of consumption (less than 4.9 g/day, or half a glass of wine per day), and 37% drank moderately (5 - 14.9 g/day, or ½ to 1 ½ glasses of wine, 1 mixed drink, or 1 beer daily).
Analysis of the data showed that women who consumed low to moderate amounts of alcohol had a lower risk for total stroke compared with women who never drank.
After adjusting for a number of variables, including smoking, physical activity, body mass index, family and personal history of heart disease, diabetes, hypertension, bilateral oophorectomy, postmenopausal status, hormone therapy, high cholesterol, multivitamin intake, aspirin, composite 6-nutrient diet score, highest level of education, husband's highest level of education, and marital status, the relative risks of stroke were 0.83 (95% confidence interval [CI], 0.75 - 0.92) for women who consumed < 5 g/day, 0.79 (95% CI, 0.70 - 0.90) for 5 to 14.9 g/day, 0.87 (95% CI, 0.72 - 1.05) for 15 to 29.9 g/day, and 1.06 (95% CI, 0.86 - 1.30) for 30 to 45 g/day. Results were similar for ischemic and hemorrhagic stroke.
The estimated risk for stroke in the highest category of reported alcohol intake did not reach statistical significance because there were very few heavy drinkers in the cohort, Dr. Jimenez pointed out.
"Moderate alcohol intake was associated with reduced risk of total stroke, and higher levels were not associated with reduced risk in this particular population, which really emphasizes the importance of moderation if you drink," she said.
"There are several ways that alcohol might reduce the risk of stroke," Dr. Jimenez speculated. "Alcohol has components which prevent blood clots and promote HDL cholesterol, which is the good cholesterol. But alcohol is like a double-edge sword because higher levels can increase high blood pressure and promote atrial fibrillation, which are also risk factors for stroke."
Dr. Jimenez stressed that women who currently do not drink should not start to drink in the belief that this will protect them from stroke.
"Our results are very much in line with the American Heart Association guidelines for up to a glass a day for women, but those recommendations are for women who are current drinkers, and we do not advocate the initiation of alcohol consumption for women who abstain from drinking," she said.
"This paper was based on a very well-done analysis with excellent ascertainment of alcohol exposure," R. Curtis Ellison, MD, professor of medicine at Boston University School of Medicine in Massachusetts, told Medscape Medical News.
"The findings from this study are not that new. Many studies have shown that stroke is in general 10, 15, 20% lower in moderate drinkers," Dr. Ellison said.
"But you have to keep supporting these findings because people are always looking for flaws. Out of 200 or 300 papers, there have been about half a dozen that have not found this, so you have to reinforce your findings. This is a very large study, and it is very useful to have such confirmation."
Dr. Jimenez and Dr. Ellison have disclosed no relevant financial relationships. Dr. Ellison reports that he is a member of the International Scientific Forum on Alcohol Research. The study was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health and the National Cancer Institute.
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