title: [Chronic headache: classification and epidemiology].
authors.forename: H
authors.initials: H
authors.lastname: Igarashi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002908:Chronic Disease; D005260:Female; D006261:Headache / Q000145:classification* / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged