BLACK WHITE DIFFERENCES IN LEUKOCYTE SUBPOPULATIONS IN MEN/

Background. Although counts of leukocytes differ substantially between blacks and whites, and are predictive of ischaemic heart disease (IHD ), racial differences in counts of leukocyte subpopulations have recei ved less attention. Methods. We examined black/white differences in le ukocyte subpopulations among 3467 white and 493 black 31-45 year-old-m en who had previously served in the US Army. Laboratory determinations were performed at a central location during 1985-1986. Results. Black men had an 840 cell/mu l (or 15%) lower mean total leukocyte count th an did white men, largely due to a 960 cell/mu l (or 25%) lower mean n eutrophil count, Although black men also had a 20% lower mean monocyte count (approximate to 70 cells/mu l) than did white men, their mean l ymphocyte count was 10% higher (approximate to 200 cells/mu l). Counts of various leukocyte subpopulations were associated with cigarette sm oking, haemoglobin levels, platelet counts, and several other characte ristics, but black/white differences in counts of neutrophils, lymphoc ytes, monocytes and other subpopulations could not be attributed to an y of the examined covariates. Conclusions. Despite the relatively low counts of leukocytes and neutrophils among black men, their lymphocyte counts are generally higher than those among white men. It is possibl e that black/white differences in counts of various cell types may inf luence race-specific rates of IHD, and future studies should attempt t o assess the importance of leukocyte subpopulations in the development of clinical disease.