By Margarita Nahapetyan
Women who consume coffee on a regular basis reduce their chances of having stroke, according to the latest findings by researchers from Spain and the United States.
The study, which was published in the February 16 issue of Circulation: Journal of the American Heart Association, found that women who drank four or more cups of coffee per day reduced their risk of stroke by 20 per cent compared to women who drank less than a cup per month. Also, it was found that women who consumed 2 or 3 cups per day reduced the risk by 19 per cent, and the risk was reduced by only 12 per cent for those who drank 5 to 7 cups per week.
The authors analyzed data on more than 83,076 healthy women, with the average age of 55 years, and who had participated in the Nurses' Health Study. Participants began the study in 1980 and had no history of stroke, heart disease, diabetes or cancer. Every 2 to 4 years during the 24 years of the study, the women were asked to fill out questionnaires in order to report their dietary habits.
Statistical tools like Cox regression models, helped the researchers to study the relative risks (RR) between the stroke incidents and coffee intake. Such factors as age, smoking habits, body mass index (BMI), physical activity, use of alcohol, menopausal status, use of hormone therapy, use of aspirin, and other dietary factors, were taken into account.
Based on all that and the information given by the women, the researchers revealed that 84 per cent of the participants drank coffee with at least some caffeine, 50 per cent drank decaf coffee, 78 per cent were tea drinkers, and 54 per cent of the participants consumed sodas containing caffeine.
Nearly 2,300 stroke incidents occurred during the 24 years of the study, 426 of which were hemorrhagic (burst blood vessel in the brain), 1,224 ischemic, which follow blood vessel blockage, and 630 were undetermined.
However, the benefits of coffee turned out to be much more significant for non-smokers. While women who did not smoke and who drank four or more cups of coffee a day had a 43 per cent reduction in stroke risk, the reduction in stroke risk lowered to only 3 per cent for women who drank 4 cups or more and smoked.
"The potential benefits of coffee cannot counterbalance the detrimental effects smoking has on health," said Esther Lopez-Garcia, lead author of the study and assistant professor of preventive medicine at the Universidad Autonoma de Madrid, Spain.
Besides smoking, such conditions as high blood pressure, diabetes, or high cholesterol also turned down the effect of coffee drinking. "The beneficial effects of coffee can only be applied to healthy people," says Lopez-Garcia. "Anyone with health problems that can be worsened by coffee (insomnia, anxiety, hypertension, or heart problems) should talk to their doctor about their specific risk."
But what turns out to be the most interesting, there is still no evidence as to what specific aspect of coffee plays the main role in stroke risk reduction. Apparently, the benefits do not come from caffeine itself because participants who were consuming tea or caffeinated soft drinks did not show similar health benefits as coffee did. Researchers assume that some other component in coffee, other than caffeine, is responsible for a positive protective effect of coffee. "Antioxidants in coffee lower inflammation and improve blood vessel function," said Lopez-Garcia.
The authors still cautioned that the current findings need more confirmation with new studies and continued research, and warned women not to indulge themselves in coffee drinking in order to reduce stroke risk.
"This is quite an early finding," said the study's co-author, Rob M. van Dam, an assistant professor at Harvard Medical School and Harvard School of Public Health, in Boston. "And previous studies have been quite small. But the data we do have is very convincing in the sense that we feel comfortable that we definitely found no association between high coffee consumption and a higher stroke risk. So women can continue to enjoy their coffee and focus on other things to reduce stroke risk, such as engaging in more physical activity, reducing salt intake and stopping smoking."