title: Comorbidity as an epidemiological construct.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Keezer
authors.forename: Josemir W
authors.initials: JW
authors.lastname: Sander
mesh_terms: D015897:Comorbidity; D004827:Epilepsy / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D008881:Migraine Disorders / Q000175:diagnosis* / Q000453:epidemiology*