Smoking, Coffee May Up Risk of Rare Type of Stroke
NEW YORK (Reuters Health) - Results of a new study suggest that smoking, coffee drinking and high blood pressure increase the risk of having a subarachnoid hemorrhage, a type of stroke caused by bleeding in the brain.
Although giving up cigarettes or getting your blood pressure under control is never a bad idea when it comes to improving health, it would be premature to say that cutting back on coffee will reduce the risk of stroke, according to Dr. W. T. Longstreth, Jr., of the University of Washington in Seattle, who was not involved in the study.
"No recommendations are warranted based on this single study," Longstreth told Reuters Health.
Subarachnoid hemorrhage is a type of stroke caused by sudden bleeding into the space between the brain and its covering. It usually occurs when a weakened blood vessel in the brain bursts. Although this type of stroke can occur at any age, it is most common among people between the ages of 25 to 50. Still, subarachnoid hemorrhages are rare, affecting about 10 out of every 100,000 people.
Risk factors for this type of stroke have not been well documented. To determine what these risk factors might be, a team at Tromso University Hospital in Norway identified cases of subarachnoid hemorrhage in a large population-based health study that is designed to identify risk factors for disease, particularly cardiovascular disease.
From a sample of more than 27,000 people, Dr. Tor Ingebrigtsen and colleagues compared 26 people who had suffered a subarachnoid hemorrhage and 104 healthy individuals matched by age and sex.
People who had a subarachnoid hemorrhage were more likely to smoke, to drink more coffee and to have high blood pressure, the researchers report in the Journal of Neurology, Neurosurgery, and Psychiatry.
The risk of subarachnoid hemorrhage was more than quadrupled in current smokers and more than doubled in former smokers. People who drank five or more cups of coffee per day were almost four times as likely to have this type of stroke. And for each increase of 20 points in blood pressure, the risk of subarachnoid hemorrhage more than doubled, the report indicates.
In contrast, other risk factors, such as being overweight or having high cholesterol, did not influence the risk of subarachnoid hemorrhage, the authors note.
Despite the findings, the jury is still out on the link between coffee consumption and the risk of subarachnoid hemorrhage, Longstreth states.
"Is the association a coincidence?" he asks in an editorial that accompanies the study. It could be, according to Longstreth, that some other characteristic of coffee drinkers, such as a greater propensity to drink alcohol, may explain the apparent link. He also points out that the study included only a small number of participants who had subarachnoid hemorrhage.
If coffee does increase the risk of subarachnoid hemorrhage, exactly how it does so is uncertain, Longstreth notes. Caffeine increases blood pressure, which could in turn raise the risk of subarachnoid hemorrhage, but Longstreth points out that the researchers did not know whether participants drank regular or decaffeinated coffee.
"So for now, sip your coffee, but with some lingering concern about this unresolved issue," Longstreth writes.