title: Parental history of stroke predicts subclinical but not clinical stroke: the Atherosclerosis Risk in Communities Study.
abstract: OBJECTIVE
  An individual with a positive family history of a disease may be at increased risk for the disease. We sought to examine whether parental history of stroke is associated with subclinical or clinical stroke in the Atherosclerosis Risk in Communities (ARIC) Study, and whether any observed association is independent of established stroke risk factors.
  
  
  METHODS
  Parental history of stroke was determined by home interview at the baseline examination. Cerebral MRI was performed on individuals from 2 ARIC field centers. Subclinical cerebral infarct cases (n=202) were defined by the presence of cerebral infarcts >3 mm. The comparison group for the subclinical cases included all individuals participating in the MRI examination who were not identified as a subclinical case (n=1533). Incidence of clinical ischemic stroke was determined by following the ARIC cohort for potential cerebrovascular events. Two hundred sixty-one validated ischemic strokes were identified; 13 775 individuals from the ARIC cohort did not experience an ischemic event.
  
  
  RESULTS
  Parental history of stroke was significantly associated with subclinical stroke after adjusting for age, gender, and race (OR 1.67, 95% CI1.23 to 2.26) and after further adjustment for multiple stroke risk factors (OR1. 64, 95% CI1.20 to 2.24). Parental history of stroke was not a significant predictor of clinical stroke in either adjustment model.
  
  
  CONCLUSIONS
  The observed increased risk of subclinical stroke among individuals with a parental history of stroke is consistent with the expression of genetic susceptibility, a shared environment, or both in the etiology of stroke. This effect did not appear to be mediated by established stroke risk factors. Parental history of stroke does not confer an increased risk of clinical stroke in this sample of middle-aged Americans.
authors.affiliation: Human Genetics Center and Institute of Molecular Medicine, University of Texas-Houston Health Science Center, Houston, TX 77030, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Morrison
authors.forename: M
authors.initials: M
authors.lastname: Fornage
authors.forename: D
authors.initials: D
authors.lastname: Liao
authors.forename: E
authors.initials: E
authors.lastname: Boerwinkle
mesh_terms: D000367:Age Factors; D001921:Brain / Q000473:pathology; D020520:Brain Infarction / Q000175:diagnosis / Q000235:genetics*; D005006:Ethnicity; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D007407:Interviews as Topic; D008279:Magnetic Resonance Imaging; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D010290:Parents; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D014481:United States / Q000453:epidemiology