Risk factors for venous thrombosis in the black population.
Risk factors for venous thrombo-embolism (VTE) in the black population are poorly characterized. Of 142 black cases tested a genetic cause was identified in only 9.1%: 4.2% had protein C deficiency, 2.8% protein S deficiency, 0.7% antithrombin deficiency and 1.4% were heterozygous for FV Leiden. We hypothesised that elevated factor VIII levels constitute a candidate risk factor for venous thrombosis in the black population. Factor VIII (FVIII:C) levels were determined in 100 black patients with VTE and 100 black controls in a case-control study. Of the patients 34% had a FVIII:C above 228 IU/dL (the 90th centile value in normal blacks) compared to 10% controls. Relative to those with FVIII:C below this value, odds ratio (OR) for risk of VTE was 4.64 (95% CI 2.02-10.85). When FVIII:C below 150 IU/dL was used as a comparator, OR was 11.1 (95% CI 4.29-29.43). There was evidence for a dose-response relationship. We propose that raised FVIII:C is a major risk factor for VTE in black subjects with prevalence and odds ratio exceeding those reported for white subjects.
Department of Haematological Medicine, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom.
Raj K
RK
Patel
Elizabeth
E
Ford
Jill
J
Thumpston
Roopen
R
Arya
D000328:Adult; D044383:Black People; D016022:Case-Control Studies; D005165:Factor V; D005169:Factor VIII / Q000032:analysis* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D020151:Protein C Deficiency; D018455:Protein S Deficiency; D012307:Risk Factors; D020246:Venous Thrombosis / Q000208:ethnology / Q000209:etiology*
C095381:factor V Leiden; D005165:Factor V; D005169:Factor VIII