RESUMO
The aim of this study was to evaluate the effect of the screening question phrasing on the 1-year prevalence figures of headache disorders, including migraine. Of a random sample of 563 invited participants in the Nord-Trøndelag Health Survey 2006-2008 in Norway, 297 (53%) met to a face-to-face interview. There were 74.1% that reported having had headache during the last year, whereas only 31.0% stated that they had suffered from headache in the same period. The 1-year prevalence of migraine was 17.2% and of tension-type headache (TTH) 51.9%. Migraine was ten times more likely (OR = 9.96, 95% CI 4.75-20.91) among those who stated that they were headache sufferers than among those who were not. Only headache sufferers had chronic TTH or medication-overuse headache. Thus "Have you suffered from headache?" can be a useful screening question in population-based questionnaire studies if the goal is to identify most migraineurs and almost all individuals with chronic headache.