Coffee lovers, please take note. Drinking three or more servings of caffeinated beverages a day increases the risk of migraine.
In a study published in the American Journal of Medicine, researchers evaluated the role of caffeinated beverages as a potential trigger of migraine.
They found that, among patients who experience episodic migraine, one to two servings of caffeinated beverages were not associated with headaches on that day, but three or more servings of caffeinated beverages may be associated with higher odds of migraine headache occurrence on that day or the following day.
"While some potential triggers - such as lack of sleep - may only increase migraine risk, the role of caffeine is particularly complex, because it may trigger an attack but may also help control symptoms, caffeine's impact depends both on dose and on frequency," said Elizabeth Mostofsky from Harvard University.
During the study, 98 adults with frequent episodic migraine completed electronic diaries every morning and every evening for at least six weeks.
Every day, participants reported the total servings of caffeinated coffee, tea, soda and energy drinks they consumed, as well as filled out twice daily headache reports detailing the onset, duration, intensity, and medications used for migraines since the previous diary entry.
Participants also provided detailed information about other common migraine triggers, including medication use, alcoholic beverage intake, activity levels, depressive symptoms, psychological stress, sleep patterns and menstrual cycles.
To evaluate the link between caffeinated beverage intake and migraine headache on the same day or on the following day, researchers used a self-matched analysis, comparing an individual participant's incidence of migraines on days with caffeinated beverage intake to that same participant's incidence of migraines on days with no caffeinated beverage intake.
The researchers further matched headache incidence by days of the week, eliminating weekend versus week day habits that may also impact migraine occurrence.
Self-matching also allowed for the variations in caffeine dose across different types of beverages and preparations.
"One serving of caffeine is typically defined as eight ounces or one cup of caffeinated coffee, six ounces of tea, a 12-ounce can of soda and a 2-ounce can of an energy drink," Mostofsky said.
"Those servings contain anywhere from 25 to 150 milligrams of caffeine, so we cannot quantify the amount of caffeine that is associated with heightened risk of migraine. However, in this self-matched analysis over only six weeks, each participant's choice and preparation of caffeinated beverages should be fairly consistent," Mostofsky added.