The Effect of Age, Sex, Parity, Haemoglobin Level, and Oral Contraceptive Preparations on the Normal Leucocyte Count

In a study of the leucocyte counts of 408 male and 789 female blood donors aged 18–65, it was found that the male total leucocyte and differential counts did not vary significantly with age. In women the neutrophil and lymphocyte counts decreased significantly with increasing age, the fall in the neutrophils being pre‐dominantly a post‐menopausal occurrence, while the decrease in lymphocyte count was more evenly distributed and remained at a lower level than the male count throughout. In contrast, analysis confined to women not using oral contraceptives revealed a lower neutrophil count, and to a lesser extent lymphocyte count, in the youngest women. The increase in neutrophil count of women using the‘Pill’was independent of the length of time the‘Pill’had been taken. The reasons for the variations in leucocyte count with increasing age are discussed, with emphasis on the possible role of oestrogens in the control of the neutrophil count.