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The association of hemorheological alterations with morbid obesity remains a question of debate. In order to ascertain whether morbid obese subjects show certain hemorheological alterations which might be involved in the higher thrombotic risk which characterizes these subjects, we determine glucose, plasma lipids, apolipoproteins, fibrinogen, hematocrit, blood viscosity (Brookfield DVIII viscosimeter), both at native and corrected hematocrit of 45%, plasma viscosity (Fresenius capillary viscosimeter), erythrocyte aggregation (Myrenne aggregometer), both at stasis and at 3 s(-1) at 45% hematocrit and erythrocyte indexes in 41 morbid obese subjects (32 female, 9 male aged 33+/-10 years), and in a well matched non-obese control group (40 female, 15 male, aged 32+/-10 years). Mean BMI in the morbid obese group was 44.9+/-6.7 kg/m2 vs 23.5+/-4.8 kg/m2 in the control group (p<0.001). Morbid obese subjects when compared with the control group showed a statistically higher glucose level (p<0.001), LDL-cholesterol (p=0.019), triglycerides (p<0.001), apoB (p=0.019), apoB/A1 (p<0.001), fibrinogen (p<0.001), erythrocyte aggregation (p<0.001), and a statistically lower HDL-cholesterol (p<0.001). No differences between both groups were observed regarding total-cholesterol, plasma viscosity, blood viscosity and hematocrit (p=0.109; p=0.690; p=0.510; p=0.950), respectively. After the adjustment for BMI, differences in glucose, LDL-cholesterol, triglycerides, apoB, apoB/A1, and erythrocyte aggregation did not reach the statistical significance, and differences in fibrinogen were borderline significant (p=0.051), showing a direct effect of BMI on the detected differences between obese and non-obese. Our results suggest that in morbid obese subjects the increased fibrinogen levels and the altered lipid profile associated with their higher BMI, could in addition to its known mechanisms on haemostasis, favour both venous and arterial thrombotic events by enhancing erythrocyte aggregation., (Copyright 2004 IOS Press)

Discrepant results have been published regarding modifications of rheological parameters in obese subjects after a low caloric diet (LCD). In order to ascertain whether a decrease in BMI associated to a LCD, is accompanied by changes in the hemorheological parameters, we determined in 41 morbid obese subjects (32 female, 9 male aged 33+/-10 years) BMI, glucose, plasmatic lipids and apolipoproteins, fibrinogen, blood viscosity (Brookfield viscosimeter), plasma viscosity (Fresenius capillary viscosimeter), erythrocyte aggregation (Myrenne aggregometer), hematocrit and erythrocyte indexes, before starting on a LCD and 1 and 3 months after. During the first month obese subjects received a very low caloric diet (VLCD) (Modifast) providing 458 kcal per day. The second and third month they received a LCD providing 1500 kcal/day for men and 1200 kcal/day for women. One month after starting on a VLCD, a statistical significant decrease in glucose (p<0.001), Total-cholesterol (p<0.001), LDL-cholesterol (p<0.001), triglycerides (p=0.012), apoB (p<0.001) and erythrocyte aggregation (p<0.001) were observed together with a concomitant decrease in BMI (p<0.001). The expected decrease in HDL-cholesterol associated with a low fat diet was also noted in these individuals. No changes in fibrinogen, hematocrit, blood viscosity or plasma viscosity were observed. At 3 months only a slight increase in BMI was observed regarding the one month period, glucose being the only parameter which remained statistically lower. All the other significant parameters returned to their basal values at 3 months. VLCD (Modifast) is associated to a significant decrease in BMI with the corresponding improvement in glucose, lipids and erythrocyte aggregation at one month. However a LCD alone does not produce a further decrease in weight and both lipids and erythrocyte aggregation return to the basal situation at three months., (Copyright 2004 IOS Press)