title: Common Familial Effects on Ischemic Stroke and Myocardial Infarction: A Prospective Population-Based Cohort Study.
abstract: BACKGROUND
  Recent genome-wide association studies suggest some overlap of genetic determinants of ischemic stroke (IS) and myocardial infarction (MI). This study aimed to assess shared familial risk between IS and MI in a large, population-wide cohort study.
  
  
  METHODS
  Study participants free of IS and MI and their affected siblings were extracted from the Swedish Hospital Discharge and Cause of Death Registers between 1987 and 2007, forming an exposed sib-pair. They were matched by birth year of both siblings and calendar period to up to five unexposed sib-pairs. Stratified Cox regression analyses were used to assess familial risk of MI and IS in those exposed to having a sibling with IS (n = 31,659) and MI (n = 62,766), respectively, compared to unexposed (n = 143,728 and 265,974).
  
  
  RESULTS
  The overall risk of MI when exposed to having a sibling with IS was statistically significantly increased (RR, 1.44; 95% CI, 1.34-1.55, p < 0.001) to a similar extent as risk of IS when exposed to having a sibling with MI (RR, 1.41; 95% CI, 1.32-1.50, p < 0.001). The familial risks were similar in full siblings for both groups (RR for MI, 1.46; 95% CI, 1.35-1.58, p < 0.001; and RR for IS, 1.40; 95% CI, 1.30-1.40, p < 0.001) and half siblings (RR for MI, 1.29; 95% CI, 1.05-1.59, p < 0.001; and RR for IS, 1.38; 95% CI, 1.16-1.65, p < 0.001).
  
  
  CONCLUSIONS
  This large, population-wide study indicates that there is considerable overlap of familial risk between IS and MI.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden ; Saw Swee Hock School of Public Health, National University of Singapore , Singapore , Singapore.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kasiman
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundholm
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Sven
authors.initials: S
authors.lastname: Sandin
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Ninoa
authors.initials: N
authors.lastname: Malki
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Pär
authors.initials: P
authors.lastname: Sparén
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet , Stockholm , Sweden ; Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University , Uppsala , Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Ingelsson
keywords: coronary heart disease; epidemiology; family history; heritability; ischemic stroke