One-year prevalence of migraine in Spain: a nationwide population-based survey.

AIM The purpose of the study was to estimate the one-year prevalence of migraine among a population-based sample of Spanish adults. METHOD Men and women aged 18-65 years were selected at random according to quotas for age, sex, size of habitat (<10,000 inhabitants, 10,001-50,000 inhabitants, 50,001-200,000 inhabitants and >200,000 inhabitants) and residence proportional to the population size of the geographical location. A random-digit-dial, computer-assisted telephone interview (CATI) survey was conducted between April and July 2006. The 2004 International Headache Society operational diagnostic criteria were applied. RESULTS From a total of 70,692 telephone calls and 26,255 (31.7%) valid contacts, 5,668 (21.6%) respondents completed the CATI survey. A total of 476 subjects (8.4%, 95% confidence interval [CI] 7.7-9.1%) with strict migraine and 236 with probable migraine (4.2%, 95% CI 3.7-4.7%) were recorded. The 1-year prevalence of total migraine (N = 712) was 12.6% (95% CI 11.6-13.6) (17.2% in females, 8.0% in males). The prevalence rates showed significant geographic variations, from 7.6% in Navarra to 18% in the Canary Islands. One-half of the subjects had migraine with aura. One-third of subjects were never diagnosed for migraine. CONCLUSIONS The one-year prevalence of migraine in Spain is 12.6%, with a prevalence of migraine with and without aura of 8.4% and probable migraine of 4.2%. These findings add data to the current understanding of migraine.