Many migraine sufferers will tell you they don't need a weatherman to tell them the forecast; their headaches signal what is coming. But there has been little scientific evidence to link the two - until now.
Researchers from Beth Israel Deaconess Medical Center - who studied 7,000 emergency-room visitors over a seven-year period - reported yesterday that headache-related hospital visits increased in the 24 hours after air temperatures rose. Lower barometric pressure in the 48 to 72 hours before a patient's arrival was also associated with a higher risk of headache.
The study used weather records and air pollution readings from a monitor on the roof of the Countway Library of Medicine and matched them to headache diagnoses from emergency doctors. For every temperature increase of 9 degrees Fahrenheit (5 degrees Celsius) in 24 hours, there was a 7.5 percent higher risk of severe headache. For every 5 millimeters the barometric pressure reading fell over 72 hours, there was a 6 percent higher risk of headache. There was no clear association with air pollutants.
"Our study was not big enough to look at air pollution definitively," Dr. Kenneth Mukamal, lead author of the study, said in an interview. "What we did see is that there are environmental triggers to headache."