title: Blood viscosity and aging.
abstract: The objective of this study was to evaluate the relationship of whole blood viscosity and its major determinants (plasma fibrinogen level, hematocrit, hemoglobin and blood cell count) to advancing age. A total of 249 subjects (mean age 49.9+/-21.5; range 19-102 years) were included in the study. They were divided into three groups, (A) <30 years of age, n, 58; (B) 30-60 years, n, 107; (C) >60 years, n, 84. Whole blood viscosity at two different rates of shear (450 and 45 s(-1)) was evaluated using a cone-plate digital viscosimeter. The hematological parameters (hematocrit, hemoglobin and blood cell count) were evaluated using an automatic Coulter Counter. Plasma fibrinogen concentration was measured by a clotting method. When both sexes are considered together, whole blood viscosity shows no significant difference among age groups. Plasma fibrinogen concentration significantly increases with age (P<0.001); hemoglobin, red blood cell count and platelet count, on contrary, are significantly lower in aged group. In the male sex, blood viscosity at higher shear rate (450 s(-1)) negatively correlates with advancing age (P<0.005). The age-related decrease of hematocrit value in the male sex accounts for this occurrence.
authors.affiliation: Department of Geriatric Medicine and Metabolic Diseases, II University of Naples, Policlinico Universitario, Piazza Miraglia 2, 80138, Naples, Italy
authors.initials: L
authors.lastname: Coppola
authors.initials: F
authors.lastname: Caserta
authors.lastname: De Lucia D
authors.initials: S
authors.lastname: Guastafierro
authors.initials: A
authors.lastname: Grassia
authors.initials: A
authors.lastname: Coppola
authors.initials: R
authors.lastname: Marfella
authors.initials: M
authors.lastname: Varricchio