A cross-sectional population-based survey of migraine and headache in 21,177 Norwegians: the Akershus sleep apnea project.

The objective was to investigate the prevalence and interrelation of migraine and headache in the general population. Forty thousand men and women aged 20-80 years from the Norwegian general population received a mailed questionnaire with questions about migraine and headache. The questionnaire response rate was 54.5%. The lifetime prevalence of migraine was 26.5% (95% CI 25.9-27.1%), i.e., 18.1% (95% CI 17.3-18.9%) in men and 34.1% (95% CI 33.2-35.0%) in women. The prevalence of migraine decreased slightly in both men and women after an age of 45. The 1 year prevalence of headache was 77.2%, i.e., 69.6% (95% CI 68.7-70.6%) in men and 84.0% (95% CI 83.3-84.7%) in women. The frequency of headache decreased with age, but some of the elders aged 70 or above experienced more frequent headache. The prevalence of being headache free increased from 19.1% (95% CI 14.2-25.6%) to 74.7% (95% CI 70.0-78.8%) in 20 and 80 years old men without co-occurrence of migraine, and from 5.1% (95% CI 2.9-8.8%) to 61.4% (95% CI 54.9-67.6%) in 20 and 80 years old women without co-occurrence of migraine. Co-occurrence of migraine significantly increased the frequency of headache and decreased the prevalence of being headache free.