Haemorheological changes in obese adolescents after short-term diet

Along with other risk factors in coronary heart and cerebrovascular disease, obesity is frequently associated with the development of atherosclerosis, a disease in which the rheological characteristics of blood are important. We studied the influence of weight reduction on haemorheological parameters of 20 obese adolescents (10 female, 10 male; aged 12-17 years) without metabolic and/or cardiovascular diseases. The control group composed 39 health non-obese subjects (19 female, 20 male; aged 13-17 years). At the beginning of the study the mean (+/- s.d.) body mass indices (BMI) of the obese adolescents were 36.0 +/- 5.3 kg/m2 in males and 36.8 +/- 5.0 kg/m2 in females. This was significantly reduced (31.5 +/- 4.9 kg/m2 in males and 32.5 +/- 4.7 kg/m2 in females) after one month following a diet of 1000 kcal/day: 25% proteins, 26% lipids and 49% carbohydrates. Before dieting, plasma fibrinogen level, whole blood viscosity at low shear rates and plasma viscosity were significantly higher in obese patients than in normal subjects, while the microhaematocrit values of the two groups were not significantly different. After dieting, plasma viscosity, the plasma fibrinogen level and the mean erythrocyte aggregation index of the patients decreased significantly compared to basal values, while whole blood viscosity did not change. Our data seem to indicate that short-term diet improves the haemorheological pattern in obese adolescents, probably as a consequence of an important metabolic rearrangement.