Are abdominal obesity and body mass index independent predictors of hemorheological parameters?

There is an association between obesity and rheological blood behavior [2, 4–7]. In this sense we have read with interest the recently published article by Brun et al. [1] in this journal. The authors evaluate, in a population of 430 subjects, the relationship between abdominal obesity and body mass index (BMI) with blood viscosity, and conclude that both anthropometric parameters are associated with increased blood viscosity but by different mechanisms, where the waist to hip ratio is a better predictor for blood viscosity than BMI. It is striking that in this study the authors do not indicate the variables included in the stepwise multivariate regression model, where plasma lipids, glucose and fibrinogen do not seem to have been included, being important from a rheological point of view. It seems that only the waist to hip ratio (WHR) and BMI were taken into account as predictors of blood viscosity. In order to clarify this issue and to know not only the relationship between the above mentioned anthropometric parameters with blood viscosity, but also with the rest of hemorheological variables (i.e. corrected blood viscosity at 45% hematocrit, plasma viscosity, erythrocyte aggregation and erythrocyte deformability), we analyzed the association of BMI and waist circumference with hemorheological parameters, and also with glucose, plasma lipids and fibrinogen in 395 healthy subjects (199 males/196 females, aged: 44.13± 12.61). We preferred to use waist circumference rather than WHR because it seems to be a stronger predictor of cardiovascular risk [3]. Anthropometric, lipidic, fibrinogen and hemorheological parameters were determined as previously [9]. A multivariate regression analysis was performed to explore the association of native blood viscosity, corrected blood viscosity, plasma viscosity, erythrocyte aggregation and erythrocyte deformability