Plasma viscosity and its biochemical predictors: associations with lifestyle factors in healthy middle-aged men

The association of lifestyle factors and biochemical variables with plasma viscosity was examined in a sample of middle-aged males of high social stat us. Analyses were performed on a subsample of men that had relevant rheolog ical and biochemical variables determined during a preventive medical asses sment conducted between 1992 and 1996. Among 622 subjects (64 smokers), mea sures of physical activity or predicted VO2max and adiposity (sum of subcut aneous skinfolds) were the lifestyle factors significantly associated with plasma viscosity (both P < 0.001). Among the biochemical variables, serum t otal protein and plasma fibrinogen concentrations accounted for most of the explained variability in plasma viscosity within subjects (combined adjust ed r(2) = 65.5%). Logarithm-transformed triglyceride, leukocyte count and s erum globulin together contributed an additional 3.0% of the variance in pl asma viscosity. Serum total protein, In triglycerides and leukocyte count d ecreased significantly across higher quartiles of predicted VO2max (all P < 0.0001), with trends towards lower fibrinogen and globulin concentrations (P = 0.054 and P = 0.050, respectively). Higher levels of adiposity were al so significantly associated with higher levels of serum total protein (Pi 0 .0001), globulin (P < 0.0001), fibrinogen (P < 0.01), leukocyte count (P < 0.05), and triglycerides (P < 0.0001). The association of lifestyle factors with the biochemical predictors of plasma viscosity may result directly fr om a pro-inflammatory state of adipose tissue origin and/or a larger plasma volume related to higher levels of cardiorespiratory fitness. Randomised c ontrolled trials of the effects of regular physical activity of different i ntensities on plasma viscosity, with reference to body composition, are now required. Blood Coagul Fibrinolysis 11:609-616 (C) 2000 Lippincott William s & Wilkins.