Factor VIII:C, ABO blood groups, and black admixture in a Brazilian sample

The effects of ABO blood groups and black admixture on the level of factor VIII:C are studied in healthy adults from Salvador, Bahia, Brazil. A racially mixed sample of 125 males was selected as follows: 25 whites, 25 light mulattoes, 25 medium mulattoes, 25 dark mulattoes, and 25 blacks. Levels of both factor VIII:C and K-PTT followed normal distributions. O blood group subjects showed lower factor VIII:C levels (110.20 +/- 30.76%) than non-O blood group members (135.24 +/- 31.42%) (t123 = 4.47; p less than 0.0001) and higher K-PTT levels (37.69 +/- 4.57 s) than non-O blood group subjects (35.25 +/- 3.82 s) (t123 = 3.24; p less than 0.01). By holding ABO blood type constant, there is a significant racial effect (white) on lowering the factor VIII:C level within both blood group O (t43 = 2.23; p less than 0.05) and non-O (t36 = 3.44; p less than 0.002). There is no interaction effect of race and blood group (F = 0.19; p greater than 0.6) on the factor VIII:C levels.