Has the prevalence of migraine and tension-type headache changed over a 12-year period? A Danish population survey

Objective: The present study aims to compare the prevalence of primary headaches in Denmark in two periods as only few replicate studies have re-evaluated the prevalence of primary headaches. Study Design and Setting: The 2001 study is a replicate of a cross-sectional survey of primary headaches in 1989, and compares 297 subjects aged 25-36 years from the general population, with the 294 comparable subjects invited in 1989. Medical doctors diagnosed all headaches using IHS-classification. Results: The participation rate was 75% in 1989 and 70% in 2001. The prevalence of migraine did not change significantly (11-15%), while the prevalence of tension-type headache (79-87%), especially of frequent tension-type headache (29-37%) increased significantly. The prevalence of chronic tension-type headache (2-5%) tended to increase. The proportion of the migraineurs with migraine 14 days or more per year increased (12-38%). Female gender was a risk factor for both primary headaches. The majority of migraineurs (92-94%) also reported coexistent tension-type headache. Conclusion: The prevalence of tension-type headache but not of migraine increased. The increase in migraine and tension-type headache frequency suggests a higher individual and societal impact of primary headaches now, than 12 years ago.