The effects of age, sex, and smoking on erythrocytes and leukocytes.

Coulter model S blood counts were related to the age, sex, and smoking habits of 1,000 clinic patients. It was found that (1) women have larger erythrocytes than men; (2) erythrocytes enlarge as people age; (3) smokers have larger erythroycytes than nonsmokers; (4) the mean leukocyte count is higher in smokers and increases in proportion to the intensity of smoking. The causes of these alterations are not known. The data indicate that the normal standards for blood cell counts should be adjusted for age, sex, and smoking habits.