Population variation in migraine prevalence--the unsolved problem.

Migraine is one of the most prevalent types of headache, which imposes a substantial burden on society as measured by direct and indirect costs. In the present work we review the obstacles to carrying out migraine epidemiological studies. Knowledge of the epidemiology of migraine has expanded because of the recent proliferation of large scale population-based studies using standardized case definitions. Previous surveys of the prevalence of migraine have given widely differing results. Even in population-based studies, there have been wide variations in estimates of migraine prevalence. The development of International Headache Society (IHS) criteria for migraine has facilitated international comparisons in epidemiologic studies by providing explicit and consistent diagnostic criteria, Recent studies using IHS diagnostic criteria have given relatively consistent estimates of migraine prevalence (about 15-18% of women and 6% of men). Studies of racial diversity in the prevalence of migraine and other headaches are still not conclusive. Further work is needed on epidemiology of migraine and collaboration between epidemiologists and clinicians seems the most likely way to advance understanding in this field.