title: What proportion of stroke is not explained by classic risk factors?
abstract: Ischemic stroke is a complex entity with multiple etiologies and variable clinical manifestations. The most frequent cause of stroke is atherosclerosis of cerebral vasculature followed by cardioembolism. Two thirds of strokes are explained by identifiable risk factors. Age, hypertension, and nonvalvular atrial fibrillation are by far the most frequent and well documented ones. Approximately 5% of strokes are caused by conditions other than atherosclerosis or heart disease, i.e., cervical arteries dissections, nonatherosclerotic vasculopathies, infectious or systemic vasculitis, and collagen vascular diseases. In spite of a thorough diagnostic evaluation, 30% of strokes remain cryptogenic, i.e., no specific cause is identified and the classic risk factors are not present. Identification of unknown environmental or genetic risk factors should be the subject of further research.
authors.affiliation: Division of Neurology, Box 2900, Durham, NC 27710, USA. ccionita@yahoo.com
authors.forename: Catalina C
authors.initials: CC
authors.lastname: Ionita
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Xavier
authors.forename: Jawad F
authors.initials: JF
authors.lastname: Kirmani
authors.forename: Subasini
authors.initials: S
authors.lastname: Dash
authors.forename: Afshin A
authors.initials: AA
authors.lastname: Divani
authors.forename: Adnan I
authors.initials: AI
authors.lastname: Qureshi
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000437:Alcoholism / Q000453:epidemiology; D001281:Atrial Fibrillation / Q000453:epidemiology; D016893:Carotid Stenosis / Q000453:epidemiology; D048909:Diabetes Complications / Q000453:epidemiology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D011379:Prognosis; D012307:Risk Factors; D017678:Sex Distribution; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology*; D015996:Survival Rate; D014481:United States / Q000453:epidemiology