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.