The effect of HDL cholesterol on blood and plasma viscosity in healthy subjects

OBJECTIVE: The influence of lipids on blood and plasma viscosity has not been fully elucidated. In this study we evaluated the contribution of HDL cholesterol to blood and plasma viscosity, in healthy subjects. METHODS: One hundred and forty-four (80 males and 64 females) subjects were enrolled among free-living participants to a cardiovascular disease screening. Exclusion criteria were: diabetes, elevated triglycerides, elevated LDL cholesterol, smoking and drug use. Blood lipids were measured by routine methods. Blood and plasma viscosity were measured by a cone-plate viscometer (Wells-Brookfield DV-III, Stoughton, U.S.A.). Subjects were divided in two groups: at low (<50 mg/dl) and high HDL cholesterol (>50 mg/dl). RESULTS: Blood and plasma viscosity were similar in subjects at low and high HDL cholesterol. In univariate analysis none of the lipid variables was significantly correlated with blood and/or plasma viscosity. In multivariate analysis only LDL cholesterol was marginally associated with blood viscosity. CONCLUSION: HDL cholesterol does not influence blood and plasma viscosity in healthy normolipidemic subjects. LDL cholesterol is marginally associated with blood viscosity.