Gender difference in theologic properties of blood and risk of cardiovascular diseases

According to official statistical data there is a significant difference be tween pre-menopausal women and age-matched men in morbidity and mortality f rom cardiac diseases and especially from myocardial infarction. There are s everal speculations regarding the nature of this phenomenon which have both supporting and refuting evidence. Our hypothesis was that due to regular physiologic bleeding, rheological pr operties of blood of pre-menopausal women are superior to those of men, and place such women at a lower risk of cardiovascular diseases than men in an y age group. We believe that this difference in hemorheological properties is due to the reduced concentration of red blood cells (RBCs) and due to gr eater population of younger and less population of older RBCs in female blo od. We studied mechanical properties of blood from 47 pre-menopausal women and 50 age-matched men. Compared to female blood, male blood had higher vis cosity and RBC aggregation and lower RBC deformability. Oxygen Delivery Ind ex, calculated as a ratio of hematocrit to blood viscosity, was found to be significantly lower in male blood. Decreased oxygen delivery along with in creased RBC aggregation and decreased RBC deformability may contribute to t he higher risk for the development of cardiovascular diseases. Regular bloo d donation may reduce hematocrit and blood viscosity, improve rheological p roperties of blood, and increase oxygen delivery in men.