title: Ethnic differences in markers of thrombophilia: implications for the investigation of ischemic stroke in multiethnic populations: the South London Ethnicity and Stroke Study.
abstract: OBJECTIVE
  The role of hypercoagulable states in the pathogenesis of ischemic stroke in black subjects is not known, and data on normal reference ranges in black populations are lacking. This study estimated ethnic-specific reference ranges in a community population to determine the prevalence of thrombophilic states in a multiethnic stroke population.
  
  
  METHODS
  Free protein S, protein C, antithrombin III, activated protein C resistance, IgG anticardiolipin antibodies, and lupus anticoagulant were determined in 130 consecutive ischemic stroke cases < or =65 years of age (50 black Caribbeans, 30 black Africans, 50 whites) and 130 community controls.
  
  
  RESULTS
  Black African controls had significantly lower protein S (P<0.001) and protein C (P=0.049) and a trend toward lower antithrombin III (P=0.056) levels compared with white controls. Black Caribbean and African controls had higher diluted Russell's viper venom time ratios compared with whites (P=0.001, P<0.001). Using ethnic-specific reference ranges, 8 controls (6.3%) and 11 cases (8.5%) had thrombophilia abnormalities (odds ratio [OR], 1.39; 95% confidence interval [CI], 0.54 to 3.57; P=0.50). ORs were 0.96 (95% CI, 0.18 to 4.99; P=0.96) for whites, 1.57 (95% CI, 0.41 to 5.94; P=0.51) for black Caribbeans, and 2.07 (95% CI, 0.18 to 24.2; P=0.95) for black Africans.
  
  
  CONCLUSIONS
  Failure to account for ethnic differences in the normal reference ranges for thrombophilia markers may lead to inappropriate diagnosis and investigation of hypercoagulable states in black individuals. Protein S and protein C deficiencies and lupus anticoagulant may contribute to stroke risk in a minority of black cases, but they are unlikely to be major contributors to the excess stroke risk seen in young individuals of African and African-Caribbean descent.
authors.affiliation: Department of Clinical Neurosciences, St. George's Hospital Medical School, Cranmer Terrace, Tooting, London SW17 0RE, UK. pjerrard@sghms.ac.uk
authors.forename: Paula
authors.initials: P
authors.lastname: Jerrard-Dunne
authors.forename: Andrew
authors.initials: A
authors.lastname: Evans
authors.forename: Rory
authors.initials: R
authors.lastname: McGovern
authors.forename: Cother
authors.initials: C
authors.lastname: Hajat
authors.forename: Lalit
authors.initials: L
authors.lastname: Kalra
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Rudd
authors.forename: Charles D
authors.initials: CD
authors.lastname: Wolfe
authors.forename: Hugh S
authors.initials: HS
authors.lastname: Markus
mesh_terms: D000349:Africa / Q000208:ethnology; D015415:Biomarkers / Q000097:blood; D044383:Black People; D017691:Caribbean Region / Q000208:ethnology; D015897:Comorbidity; D005260:Female; D006801:Humans; D008131:London / Q000453:epidemiology; D016682:Lupus Coagulation Inhibitor / Q000097:blood; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011486:Protein C / Q000032:analysis; D017293:Protein S / Q000032:analysis; D012016:Reference Values; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D019851:Thrombophilia / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000208:ethnology*; D044465:White People
chemical_list: D015415:Biomarkers; D016682:Lupus Coagulation Inhibitor; D011486:Protein C; D017293:Protein S