An update on the epidemiology of migraine.

Epidemiologic studies provide estimates of the scope and distribution of the public health problems posed by migraine. These studies have been facilitated by the development of the International Headache Society criteria for migraine, which have now been used in separate prevalence studies in several countries. In this article, we review some of the methodological challenges in studying migraine epidemiology, report recent results from studies using IHS criteria, and suggest directions for future research.