Hyperviscosity and microproteinuria in central obesity: Relevance to cardiovascular risk

OBJECTIVES: To investigate the role of blood rheology changes in the occurrence of glomerular proteinuria in obese patients with central fat distribution. SUBJECTS: Fifty-nine obese out-patients (31 with central and 28 with peripheral body fat distribution) and 24 healthy subjects. MEASUREMENTS: Blood and plasma viscosity (Rotational viscometer CV100 HAAKE), erythrocyte deformability (whole-blood filtration time), fibrinogen (nephelometry), urinary excretion rates of albumin, IgG, transferrin and IgA (nephelometry). RESULTS: Higher blood viscosity (at low and high shear-rates), plasma viscosity, fibrinogen, erythrocyte aggregability and lower erythrocyte deformability were found in patients with central obesity than in patients with peripheral obesity (P<0.01) and in healthy subjects (P<0.001). Furthermore an increased urinary excretion rate of albumin (P<0.001), IgG (P<0.001), transferrin (P<0.01) and IgA (P<0.05) was found in patients with central obesity than in the other two groups. Blood hyperviscosity (at shear-rate 1 s(-1) and 1/200 ratio) significantly correlated with the amount of urinary excretion of proteins independently of the other clinical and metabolic variables. CONCLUSIONS: The data demonstrated haemorheologic disorders related to pathologic proteinuria in patients with central obesity. The interaction between these two components may increase the risk of widespread cardiovascular disease.