Platelet aggregation, blood viscosity and serum lipids in hypertensive and obese children

A group of 35 patients (median age 15.5 years, range 8-17 years) with juvenile essential hypertension, 15 with body mass index (BMI kg/m(2)) < 25 and 20 with BMI > 25, as well as 35 age and sex matched controls (BMI < 25 n = 20; BMI > 25 n = 15) were investigated to study the role of hypertension and obesity, separately and in combination, on in vitro platelet aggregation, blood and plasma viscosity, plasma lipid concentrations and lipid peroxidation as well as nitric oxide (NO) production. Obese children (hypertensive and controls) had significantly higher concentrations of total cholesterol and triglycerides. The levels of high density lipoprotein (HDL)-cholesterol were lower in obese hypertensive children than their non-obese counterparts. There was a significant increase in platelet aggregation and a decrease in NO levels in hypertensive patients (obese and non-obese) reflecting a significant negative correlation (r=-0.553 and -0.530, n=35; P < 0.01, respectively). However, an increased tendency to aggregation was also evident in obese normotensive patients. A significant positive correlation was observed between the platelet aggregation and BMI (r=0.501, n=35; P < 0.01). Plasma free thiols were decreased in hypertensive children independent of their BMI. An increased lipid peroxidation and higher blood and plasma viscosity were found only in obese patients with hypertension. Multivariate analysis revealed significant interactions in the effects of obesity and hypertension on platelet aggregation and thiol oxidation. Conclusion: In obese children an increased platelet aggregation and oxidative insult contribute to the development of hypertension and to the promotion of vascular damage.