EFFECT OF CHINOOK WINDS ON THE PROBABILITY OF MIGRAINE HEADACHE OCCURRENCE

Our objective was to determine if Chinook weather conditions in the Ca lgary area increase the probability of headache attacks in migraine su fferers. Environment Canada meteorologic summaries for January through June 1992 were analyzed and times of Chinook wind onset identified. C hinook weather conditions were defined as calendar days when Chinook w inds were present and the calendar day immediately preceding Chinook w ind onset. The diaries of 13 migraine patients were analyzed, and time s of headache onset classified according to the existing weather condi tions. The probability of migraine headache onset was greater on days with Chinook weather (17.26%) than on non-Chinook days (14.65%) (P=0.0 42). Older patients appeared more weather sensitive than younger patie nts. For patients over age 50, the probability of migraine occurrence on Chinook weather days was much greater than on non-Chinook days (P=0 .007). Chinook weather conditions increase the probability of migraine headache occurrence. Older migraine sufferers appear particularly vul nerable to this effect.