Table 2.

Distribution of ABO blood group and Rh type among subjects from the NHS, HPFS, and US white population^*

ABO blood group	NHS (%)	HPFS (%)	Total study population (%)	US white population† (%)
O	43	43	43	45
A	36	37	36	40
AB	8	8	8	4
B	13	12	13	11
Rh negative	22	21	22	17
Rh positive	78	79	78	83

^*NHS = Nurses’ Health Study; HPFS = Health Professionals Follow-up Study.

^†Data from references (29,30).