title: A study of twins and stroke.
abstract: OBJECTIVE
  Although there are strong genetic contributions to coronary artery disease, only a few studies have considered heritable influences on stroke.
  
  
  METHODS
  We investigated the role of genetic factors in stroke using the Twin Registry maintained by the National Academy of Sciences-National Research Council. The registry includes 15,948 male twin pairs born between 1917 and 1927. In 1985, 9,475 twins responded to a mailed questionnaire, which covered vascular risk factors, cardiac events, and stroke.
  
  
  RESULTS
  Analysis of twin pairs in which both responded to the questionnaire, and a question on stroke, indicated proband concordance rates of 17.7% for monozygotic pairs and 3.6% for dizygotic pairs (relative risk = 4.3; chi 2 = 4.94, df = 1; p less than 0.05).
  
  
  CONCLUSIONS
  This nearly fivefold increase in the prevalence of stroke among the monozygotic compared with the dizygotic twin pairs suggests that genetic factors are involved in the etiology of stroke. The twin study paradigm holds considerable promise for identifying both genetic and environmental influences on stroke.
authors.affiliation: Department of Neurology, Yale University School of Medicine, New Haven, Conn. 06510.
authors.forename: L M
authors.initials: LM
authors.lastname: Brass
authors.forename: J L
authors.initials: JL
authors.lastname: Isaacsohn
authors.forename: K R
authors.initials: KR
authors.lastname: Merikangas
authors.forename: C D
authors.initials: CD
authors.lastname: Robinette
mesh_terms: D002561:Cerebrovascular Disorders / Q000453:epidemiology* / Q000401:mortality; D015331:Cohort Studies; D004200:Diseases in Twins; D006801:Humans; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D016019:Survival Analysis; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic