Trigger factors of migraine and tension-type headache: experience and knowledge of the patients.

The objective was to examine potential trigger factors of migraine and tension-type headache (TTH) in clinic patients and in subjects from the population and to compare the patients' personal experience with their theoretical knowledge. A cross-sectional study was carried out in a headache centre. There were 120 subjects comprising 66 patients with migraine and 22 with TTH from a headache outpatient clinic and 32 persons with headache (migraine or TTH) from the population. A semistructured interview covering biographic data, lifestyle, medical history, headache characteristics and 25 potential trigger factors differentiating between the patients' personal experience and their theoretical knowledge was used. The most common trigger factors experienced by the patients were weather (82.5%), stress (66.7%), menstruation (51.4%) and relaxation after stress (50%). The vast majority of triggers occurred occasionally and not consistently. The patients experienced 8.9+/-4.3 trigger factors (range 0-20) and they knew 13.2+/-6.0 (range 1-27). The number of experienced triggers was smallest in the population group (p=0.002), whereas the number of triggers known did not differ in the three study groups. Comparing theoretical knowledge with personal experience showed the largest differences for oral contraceptives (65.0 vs. 14.7%, p<0.001), chocolate (61.7 vs. 14.3%, p>0.001) and cheese (52.5 vs. 8.4%, p<0.001). In conclusion, almost all trigger factors are experienced occasionally and not consistently by the majority of patients. Subjects from the population experience trigger factors less often than clinic patients. The difference between theoretical knowledge and personal experience is largest for oral contraceptives, chocolate and cheese.