Coffee: It's a GOOD thing!
Abstract & Commentary
By Barbara A. Phillips, MD, MSPH, Professor of Medicine, University of Kentucky; Director, Sleep Disorders Center, Samaritan Hospital, Lexington. Dr. Phillips serves on the speaker's bureaus for Cephalon, Resmed, and Respironics.
Synopsis: Women who drink little or no coffee appear to be at an increased risk of stroke compared with those who drink moderate amounts of coffee.
Source: Larsson SC, et al. Coffee consumption and risk of stroke in women. DOI: 10.1161/STROKEAHA.110.603787. Published online March 10, 2011.
This report results from a secondary analysis of the swedish mammography Cohort, which is a population-based prospective study of Swedish women born between 1914 and 1948. The findings are based on two questionnaires completed by 39,227 women approximately 10 years apart. These questionnaires included items about diet and other lifestyle factors. Coffee consumption was assessed by asking respondents how many cups of coffee per day or per week they consumed during the past year. The questionnaire did not inquire about decaffeinated coffee because consumption of decaffeinated coffee in Sweden is very low. The investigators collected data about and controlled for smoking, education, body mass index, total physical activity, self-reported hypertension, diabetes, aspirin use, family history of myocardial infarction before age 60, daily caloric intake, alcohol consumption, and intake of red meat, fish, fruits, and vegetables. Stroke was classified as cerebral infarction, intracerebral hemorrhage, and unspecified stroke based on the International Classification of Diseases 10.
At baseline, the cohort was about 61 years old. The median coffee consumption was 3 cups/day. Compared with women with low coffee consumption, those with high consumption were less likely to have a university education, consumed fewer fruits and vegetables, and were more likely to be smokers. However, they were also less likely to have a history of diabetes or hypertension.
Over about 10 years of follow-up, there were 1680 strokes in this group of women, including 1310 cerebral infarctions, 154 intracerebral hemorrhages, 79 subarachnoid hemorrhages, and 137 unspecified strokes. As expected, stroke risk was positively correlated with smoking, history of hypertension, obesity, and family history of coronary heart disease. Risk of stroke was inversely correlated with education. Aspirin use and exercise were not associated with overall or specific stroke risk.
Before adjustment for other lifestyle factors and their association with stroke, there was no statistically significant association between consumption of coffee and risk of stroke in the age-adjusted analysis. However, after adjustment for smoking (in particular) and other risk factors, women who consumed at least 1 cup of coffee per day had a statistically significant 22% to 25% lower risk of stroke compared with those who drank less than 1 cup of coffee per day. With regard to specific types of stroke, coffee consumption was associated with decreased risk of cerebral infarction (by far the most prevalent kind of stroke) and subarachnoid hemorrhage but not with risk of intracerebral hemorrhage. Increased coffee consumption was associated with reduced risk of cerebral infarction and subarachnoid hemorrhage, but not with overall risk of stroke.
Commentary
This is not the first study to show that coffee consumption is associated with a reduced risk of stroke, but it is a large cohort that is carefully analyzed, so it is particularly noteworthy. In the Nurses' Health Study, women who drank at least 4 cups of coffee a day had a reduced risk of stroke,1 so this paper confirms that finding, while suggesting that even 1 cup of coffee may confer some protection. There are also reports indicating that coffee consumption is associated with reduced risk of stroke in men,2 but not all studies demonstrate a reduced risk of stroke among coffee drinkers.3-5
That coffee consumption could reduce the risk of stroke is biologically plausible. Coffee drinking has been associated with reduced inflammation,6 reduction in oxidative stress,7 and improved insulin sensitivity.8 And that's not all! A systematic review suggests that coffee consumption may reduce the risk of Type 2 diabetes.9
In an era when counseling about lifestyle is increasingly important and time to do so is increasingly scarce, it's probably time to remove admonitions against coffee drinking from routine lifestyle recommendations.
References
1. Lopez-Garcia E, et al. Coffee consumption and risk of stroke in women. Circulation 2009;119:1116-1123.
2. Larsson SC, et al. Coffee and tea consumption and risk of stroke subtypes in male smokers. Stroke 2008;39:1681-1687.
3. Hakim AA, et al. Coffee consumption in hypertensive men in older middle-age and the risk of stroke: The Honolulu Heart Program. J Clin Epidemiol 1998;51:487-494.
4. Leurs LJ, et al. Total fluid and specific beverage intake and mortality due to IHD and stroke in The Netherlands cohort study. Br J Nutr 2010:1-10.
5. Mineharu Y, et al. Coffee, green tea, black tea and oolong tea consumption and risk of mortality from cardiovascular disease in Japanese men and women. J Epidemiol Community Health 2011;65:230-240.
6. Lopez-Garcia E, et al. Coffee consumption and markers of inflammation and endothelial dysfunction in healthy and diabetic women. Am J Clin Nutr 2006;84:888–893.
7. Gomez-Ruiz JA, et al. In vitro antioxidant activity of coffee compounds and their metabolites. J Agric Food Chem 2007;55:6962-6969.
8. Arnlov J, et al. Coffee consumption and insulin sensitivity. JAMA 2004;291:1199-1201.
9. van Dam RM, Hu FB. Coffee consumption and risk of type 2 diabetes: A systematic review. JAMA 2005;294:97-104.
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