Factor VIII (AHG) levels in 1016 regular blood donors. The effects of age, sex, and ABO blood groups.

Factor VIII (AHG) activity was assayed in the plasma specimens from 1016 regular and controlled blood donors. Age and ABO blood groups had highly significant effects on factor VIII concentrations, whereas the effect of sex was not significant. The median in the donors of blood group O rose from 87% at the age of 20 to 119% at the age of 60 years, and the median in blood groups A and B+AB of corresponding ages rose from 108 to 147%. An interaction effect of age and blood groups was present only at the 5% level of significance. The present data and the previous findings of others suggest the existence of an association between high factor VIII levels and thrombotic states.