Effects of age and sex on rheological properties of blood

Abstract

We have studied rheological properties of blood (viscosity, concentration of erythrocytes, erythrocyte sedimentation rate, prothrombin index, and fibrinogen and lipid concentration) in healthy men and women at the age of 1 to 75 years. We have found an increase in blood viscosity from childhood to adult age. Blood viscosity decreased in elderly men; but it progressively increased with age in women. Three age groups have been distinguished: (1) from infancy to childhood (3.6 ± 0.07 mPa s regardless of age); (2) from adolescence to the adult age (5.1 ± 0.06 mPa s in men and 4.3 ± 0.05 mPa s in women); (3) elderly and old age (4.7 ± 0.13 mPa s in men and 4.4 ± 0.09 mPa s in women). In adult subjects, blood viscosity values were significantly different in men and women (p < 0.001). There were also sex-related differences in determination coefficients of the relationship between blood viscosity and the concentration of erythrocytes (RM2 = 0.41, p < 0.001; RF2 = 0.35, p < 0.001) and viscosity and cholesterol level (RM2 = 0.47, p < 0.001; RF2 = 0.68, p < 0.001). The factor analysis has shown that blood viscosity depends on the concentration of erythrocytes by 28%, fibrinogen level by 23%, and cholesterol level by 20%.