Risk factors for ischemic stroke subtypes: the Atherosclerosis Risk in Communities study.
OBJECTIVE
To evaluate risk factors for ischemic stroke by its subtypes may contribute to more effective prevention of ischemic stroke, but few prospective studies have characterized risk factors for specific subtypes of ischemic stroke.


METHODS
Between 1987 and 1989, 14,448 men and women aged 45 to 64 years and free of clinical stroke took part in the first examination of the Atherosclerosis Risk in Communities study. The incidence of stroke was ascertained from hospital surveillance records.


RESULTS
During an average follow-up of 13.4-years, 531 incident ischemic strokes occurred (105 lacunar, 326 nonlacunar, and 100 cardioembolic). Blacks had a 3-fold higher multivariate-adjusted risk ratio of lacunar stroke compared with whites. No racial difference in nonlacunar or cardioembolic strokes was found after adjusting for prevalent risk factors. In addition to traditional risk factors, nontraditional risk factors, such as waist-to-hip ratio, history of coronary heart disease, left ventricular hypertrophy, lipoprotein(a), and von Willebrand factor, were associated with increased risk for nonlacunar stroke, whereas lacunar stroke was related to only 1 nontraditional risk factor, white blood cell count. The population-attributable fraction (PAF) for hypertension was approximately 35% for all ischemic stroke subtypes. The respective PAFs for diabetes and current smoking were 26.3% and 22.0% for lacunar versus 11.3% and 11.4% for nonlacunar stroke. The PAF for elevated von Willebrand factor was greater than that for current smoking for cardioembolic stroke.


CONCLUSIONS
The impact of traditional and nontraditional risk factors other than hypertension on the incidence of ischemic stroke varied according to its subtype.
Ohira
Tetsuya
T
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, 1300 S 2nd St, Minneapolis, MN 55454-1015, USA.
Shahar
Eyal
E
Chambless
Lloyd E
LE
Rosamond
Wayne D
WD
Mosley
Thomas H
TH
Folsom
Aaron R
AR
D001741:Black or African American / Q000706:statistics & numerical data; D002545:Brain Ischemia / Q000145:classification / Q000453:epidemiology*; D015897:Comorbidity; D003327:Coronary Disease / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D004522:Educational Status; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D017379:Hypertrophy, Left Ventricular / Q000453:epidemiology; D015994:Incidence; D020766:Intracranial Embolism / Q000453:epidemiology; D007958:Leukocyte Count; D017270:Lipoprotein(a) / Q000032:analysis; D008297:Male; D008396:Maryland / Q000453:epidemiology; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D008922:Mississippi / Q000453:epidemiology; D015999:Multivariate Analysis; D009657:North Carolina / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D049629:Waist-Hip Ratio; D044465:White People / Q000706:statistics & numerical data; D014841:von Willebrand Factor / Q000032:analysis
D017270:Lipoprotein(a); D014841:von Willebrand Factor; D005340:Fibrinogen