Plasma and serum viscosity in Nigerian diabetics.

Relative plasma (RPV) and serum (RSV) viscosities were determined in 71 Nigerian diabetics, with and without hypertension, and compared with an age and sex matched normotensive non-diabetic control group. Viscosity was measured by a simple capillary viscometer. RPV and RSV were statistically significantly raised in diabetics compared with controls (p less than 0.001). RPV was 5.03% and RSV was 4.82% higher than non-diabetic values. There was no significant difference in either RPV or RSV due to sex. Also, no relation of RPV or RSV to age, duration of diabetes or type of treatment was identified. Plasma fibrinogen concentration correlated positively and significantly (r = 0.46; p less than 0.001) with RPV. However, whereas a significant rise was observed for total serum protein, albumin (p less than 0.001) and serum globulin concentrations (p less than 0.005), only the gamma-globulin fraction correlated significantly with RSV (r = 0.27; p less than 0.05). RPV was significantly raised in hypertensive diabetics compared with normotensive diabetics (p less than 0.02) but there was no significant difference in RSV of diabetics attributable to hypertension. Our findings show that fibrinogen predominantly contributes to the increased plasma viscosity while the gamma-globulin made the greatest contribution to serum viscosity in Nigerian diabetics. We suggest that abnormally raised plasma and serum viscosities, by contributing to disturbances in normal blood flow and metabolism, may play an essential role in the development of both micro-circulatory disorders and hypertension in some Nigerian diabetics.