Using a case-crossover design, each subject served as his/her own control. All the subjects were patients with a confirmed diagnosis of ischemic stroke. Coffee consumption information one hour before the onset of stroke symptoms was compared with their frequency of coffee consumption in the previous year.
They found that drinking coffee doubles your risk of ischemic stroke onset in the next hour compared to drinking other caffeinated drinks such as tea or cola; which may be due to lower concentrations of caffeine in those drinks.
When they looked at the frequency of caffeinated coffee intake in the previous week, they found that only people who were drinking ≤1 cup of coffee per day had increased risk for ischemic stroke in the following hour.
The take-home message?
- Drinking coffee temporarily increases one’s risk of ischemic stroke – especially so for infrequent drinkers (≤1 cup of coffee per day).
Well, I don’t think I’m willing to forsake my coffee just yet so I’m going to have 2 cups a day instead of my usual 1 a day.
Mostofsky E, Schlaug G, Mukamal KJ, Rosamond WD, & Mittleman MA (2010). Coffee and acute ischemic stroke onset: The Stroke Onset Study. Neurology PMID: 20881275