Precipitating factors of headache. A prospective study in a national control-matched survey in migraineurs and nonmigraineurs.

Prospective studies of precipitating factors in migraine are rare. Mig Access is a national control-matched survey conducted to evaluate the access of migraineurs to health care in France. This study allowed us to screen prospectively some precipitating factors of headache in migraineurs and in nonmigraineurs. Three hundred eighty-five migraineurs (group 1) and 313 nonmigraineurs (group 2) kept a diary for a 3-month period (a total of 35,805 day in group 1 and 29,109 days in group 2). Precipitating factors were reported for each headache period. Headache intensity was self-assessed during each headache period using a visual analog scale of 0 to 100. Headache was reported on 4274 days (12%) in group 1 and on 602 days (2%) in group 2. Headache intensity was greater in group 1 (39 +/- 20 versus 32 +/- 19, P < .05). The most frequent precipitating factors (reported at least once by more than 10% of subjects [range 18% to 80%] in both groups) were fatigue and/or sleep, stress, food and/or drinks, menstruation, heat/cold/weather, and infections in both groups. All these factors except infections were reported to cause headache more frequently in migraineurs than in nonmigraineurs. Mean intensity of headache related to fatigue and/or sleep, stress, food and/or drinks, hot/cold weather, and menstruation varied from 37 to 43 in migraineurs and from 29 to 35 in nonmigraineurs. Headache with the highest mean intensity was due to infections in the two groups (47 +/- 20 in group 1, 45 +/- 23 in group 2). Our results support that endogenous factors are the most frequent triggers of headache in migraineurs. The most frequent precipitating factors of headache appear identical in migraineurs and in nonmigraineurs. Our results suggest that similar triggers could precipitate headache of different type in these two populations.