SAN DIEGO — Coffee consumption by adults is associated with a reduced prevalence of stroke, and the more cups that are guzzled per day, the greater the protective effect, results from a large study show.
In an interview at the International Stroke Conference, lead study investigator Dr. David S. Liebeskind cautioned that further studies are required to pursue the underlying beneficial effects of coffee on stroke before specific recommendations about consumption can be made.
“Is this a green light to go out and start drinking coffee? I don't think so,” said Dr. Liebeskind, associate neurology director at the University of California, Los Angeles, Stroke Center. “There's a danger in the fact that some people may be very sensitive to caffeine, and the caffeine content varying amongst coffee products is very different.
“Coffee consumption can increase your blood pressure in the short term. Any increase in blood pressure is seen as a risk factor for stroke, but it's the long-term or sustained high blood pressure on a daily basis that really drives that risk.”
Presented during a poster session at the conference, the study used data from the Third National Health and Nutrition Examination Survey (NHANES III) to examine the relationship between coffee consumption and stroke in 19,994 respondents. They used multivariate logistic regression to relate the amount of coffee use reported by respondents while controlling for other vascular risk factors. They also analyzed the amount of caffeine use with respect to self-reported transient ischemic attack (TIA) or stroke symptoms.
The median age of the survey respondents was 44 years, 53% were female, and the median self-reported coffee consumption was 1 cup per day, with a range of 0–20 cups.
The researchers reported that 644 respondents (3.2%) had been told by their physician that they had suffered a stroke.
Noncoffee drinkers had higher rates of stroke, compared with those who reported regular coffee consumption, and there was a dose-related response to the protective effect. For example, the prevalence of stroke was 5% among those who reported consuming 1–2 cups per day, compared with 3.5% among those consuming 3–4 cups per day and 2.9% among those consuming more than 6 cups per day.
Coffee consumption was higher among men, compared with women; higher among those aged 50 and older, compared with their younger counterparts; and highest among whites, followed by blacks, Hispanics, and respondents from other ethnic groups.
“Interestingly, cardiac disease, diabetes, and hypertension were all less frequent with increasing number of cups of coffee per day,” the researchers noted in their poster. “Other habits such as smoking were more frequent in heavy coffee drinkers. TIA or stroke symptoms were far less common in subjects reporting greater than six cups of coffee intake per day.”
Dr. Liebeskind, who is known primarily for his research work in stroke imaging, said the mechanism of action behind coffee's possible impact on the reduced prevalence of stroke remains unclear. “Perhaps there's a synergistic effect between the caffeine and another component,” he said. “I don't see coffee as a drug for stroke, yet it remains impressive that heavy coffee drinkers have lower stroke prevalence. Whenever we estimate risk or tailor preventive strategies to avert future strokes, we need to identify influential variables.”
The conference was sponsored by the American Heart Association. Dr. Liebeskind had no conflicts to disclose.
'I don't see coffee as a drug for stroke, [but] … heavy coffee drinkers have lower stroke prevalence.' DR. LIEBESKIND