Researchers from Harvard and Madrid report that women who consumed four cups of coffee every day were at a 20 per cent lower risk of strokes than women who consumed less than one cup per month.
The results are published in the journal Circulation.
Coffee, one of the world's largest traded commodities produced in more than 60 countries and generating more than $70bn in retail sales a year, continues to spawn research and interest, and has been linked to reduced risks of certain diseases, especially of the liver and diabetes.
The new study looked at data from of 83,076 women aged between 33 and 60 taking part in the Nurses' Health Study. Over the course of 24 years, the researchers report that 2,280 strokes were documented. Of these 426 were classified as hemorrhagic stroke, 1,224 as ischemic stroke, and 630 were undetermined.
Based on results of a validated food frequency questionnaire, the researchers, led by Esther Lopez-Garcia, report that 84 per cent of the women consumed at least some caffeinated coffee. Furthermore, 50 per cent admitted drinking decaffeinated coffee, 78 per cent were tea drinkers, and 54 per cent drank caffeinated sodas.
In challenge to previous findings, the researchers report no link between a change in stroke risk among women who developed high blood pressure, diabetes, or high cholesterol during the study.
The apparent benefits of coffee consumption were increased amongst people who had never smoked, and women who had quit smoking. In this subgroup, the researchers noted a 43 per cent reduction in the risk of stroke for women who consumed four cups of coffee every day compared to women who consumed less than one cup per month.
Similar coffee-drinking habits amongst smokers were associated with only a three per cent reduction, however.
Interestingly, no statistically significant benefits were observed when the researchers considered decaffeinated coffee consumption, or when they focused their study on other drinks containing caffeine, like tea and caffeinated soft drinks.
Question marks remain over the actual constituents in the beverage that may be conferring a benefit, as well as why caffeinated tea and soft drinks did not produce the same benefits.
“Long-term coffee consumption was not associated with an increased risk of stroke in women. In contrast, our data suggest that coffee consumption may modestly reduce risk of stroke,” concluded the researchers.
Source: CirculationPublished online ahead of print 16 February 2009, doi: 10.1161/CIRCULATIONAHA.108.826164"Coffee Consumption and Risk of Stroke in Women"
Authors: Esther Lopez-Garcia, F. Rodriguez-Artalejo, K.M. Rexrode, G. Logroscino, F.B. Hu, R.M. van Dam